{
 "version": "2.2",
 "instance": {
  "bbplc-20251231.htm": {
   "nsprefix": "bbplc",
   "nsuri": "http://www.home.barclays/20251231",
   "dts": {
    "inline": {
     "local": [
      "bbplc-20251231.htm"
     ]
    },
    "schema": {
     "local": [
      "bbplc-20251231.xsd"
     ],
     "remote": [
      "http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd",
      "http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd",
      "http://www.xbrl.org/2003/xl-2003-12-31.xsd",
      "http://www.xbrl.org/2003/xlink-2003-12-31.xsd",
      "http://www.xbrl.org/2005/xbrldt-2005.xsd",
      "http://www.xbrl.org/2006/ref-2006-02-27.xsd",
      "http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd",
      "http://www.xbrl.org/lrr/role/net-2009-12-16.xsd",
      "http://www.xbrl.org/lrr/role/reference-2009-12-16.xsd",
      "https://www.xbrl.org/2020/extensible-enumerations-2.0.xsd",
      "https://www.xbrl.org/dtr/type/2020-01-21/types.xsd",
      "https://www.xbrl.org/dtr/type/2022-03-31/types.xsd",
      "https://www.xbrl.org/dtr/type/2024-01-31/types.xsd",
      "https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd",
      "https://xbrl.fasb.org/srt/2025/elts/srt-roles-2025.xsd",
      "https://xbrl.fasb.org/srt/2025/elts/srt-types-2025.xsd",
      "https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd",
      "https://xbrl.fasb.org/us-gaap/2025/elts/us-roles-2025.xsd",
      "https://xbrl.fasb.org/us-gaap/2025/elts/us-types-2025.xsd",
      "https://xbrl.ifrs.org/taxonomy/2025-03-27/full_ifrs/dimensions-ea/rol_ifrs_ea-dim_2025-03-27.xsd",
      "https://xbrl.ifrs.org/taxonomy/2025-03-27/full_ifrs/dimensions/rol_full_ifrs-dim_2025-03-27.xsd",
      "https://xbrl.ifrs.org/taxonomy/2025-03-27/full_ifrs/full_ifrs-cor_2025-03-27.xsd",
      "https://xbrl.sec.gov/country/2025/country-2025.xsd",
      "https://xbrl.sec.gov/currency/2025/currency-2025.xsd",
      "https://xbrl.sec.gov/cyd/2025/cyd-2025.xsd",
      "https://xbrl.sec.gov/cyd/2025/cyd-af-2025.xsd",
      "https://xbrl.sec.gov/cyd/2025/cyd-af-sub-2025.xsd",
      "https://xbrl.sec.gov/dei/2025/dei-2025.xsd",
      "https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd",
      "https://xbrl.sec.gov/ecd/2025/ecd-sub-2025.xsd",
      "https://xbrl.sec.gov/stpr/2025/stpr-2025.xsd"
     ]
    },
    "calculationLink": {
     "local": [
      "bbplc-20251231_cal.xml"
     ]
    },
    "definitionLink": {
     "local": [
      "bbplc-20251231_def.xml"
     ],
     "remote": [
      "https://xbrl.ifrs.org/taxonomy/2025-03-27/full_ifrs/dimensions-ea/dim_ifrs_ea_2025-03-27_role-995000.xml",
      "https://xbrl.ifrs.org/taxonomy/2025-03-27/full_ifrs/dimensions/dim_full_ifrs_2025-03-27_role-995000.xml"
     ]
    },
    "labelLink": {
     "local": [
      "bbplc-20251231_lab.xml"
     ]
    },
    "presentationLink": {
     "local": [
      "bbplc-20251231_pre.xml"
     ]
    }
   },
   "keyStandard": 647,
   "keyCustom": 256,
   "axisStandard": 73,
   "axisCustom": 5,
   "memberStandard": 174,
   "memberCustom": 337,
   "hidden": {
    "total": 9,
    "http://www.home.barclays/20251231": 5,
    "http://xbrl.sec.gov/dei/2025": 4
   },
   "contextCount": 6242,
   "entityCount": 1,
   "segmentCount": 559,
   "elementCount": 1893,
   "unitCount": 32,
   "baseTaxonomies": {
    "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full": 9771,
    "http://xbrl.sec.gov/dei/2025": 51,
    "http://xbrl.sec.gov/cyd/2025": 15,
    "http://xbrl.sec.gov/ecd/2025": 1
   },
   "report": {
    "R1": {
     "role": "http://www.home.barclays/role/Cover",
     "longName": "0000001 - Document - Cover",
     "shortName": "Cover",
     "isDefault": "true",
     "groupType": "document",
     "subGroupType": "",
     "menuCat": "Cover",
     "order": "1",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "dei:DocumentType",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "dei:DocumentType",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R2": {
     "role": "http://www.home.barclays/role/AuditInformation",
     "longName": "0000002 - Document - Audit Information",
     "shortName": "Audit Information",
     "isDefault": "false",
     "groupType": "document",
     "subGroupType": "",
     "menuCat": "Cover",
     "order": "2",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "dei:AuditorName",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "dei:AuditorName",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R3": {
     "role": "http://www.home.barclays/role/Consolidatedincomestatement",
     "longName": "9952151 - Statement - Consolidated income statement",
     "shortName": "Consolidated income statement",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "",
     "menuCat": "Statements",
     "order": "3",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:InterestRevenueCalculatedUsingEffectiveInterestMethod",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfNetInterestIncomeTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ShareOfProfitLossOfAssociatesAndJointVenturesAccountedForUsingEquityMethod",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R4": {
     "role": "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
     "longName": "9952153 - Statement - Consolidated statement of comprehensive income",
     "shortName": "Consolidated statement of comprehensive income",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "",
     "menuCat": "Statements",
     "order": "4",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ProfitLoss",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:OtherComprehensiveIncomeBeforeTaxExchangeDifferencesOnTranslation",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R5": {
     "role": "http://www.home.barclays/role/ConsolidatedstatementofcomprehensiveincomeParenthetical",
     "longName": "9952154 - Statement - Consolidated statement of comprehensive income (Parenthetical)",
     "shortName": "Consolidated statement of comprehensive income (Parenthetical)",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "parenthetical",
     "menuCat": "Statements",
     "order": "5",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ReclassificationAdjustmentsOnExchangeDifferencesOnTranslationNetOfTax",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "link:footnote",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ReclassificationAdjustmentsOnExchangeDifferencesOnTranslationNetOfTax",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "link:footnote",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R6": {
     "role": "http://www.home.barclays/role/Consolidatedbalancesheet",
     "longName": "9952155 - Statement - Consolidated balance sheet",
     "shortName": "Consolidated balance sheet",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "",
     "menuCat": "Statements",
     "order": "6",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:CashAndBankBalancesAtCentralBanks",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": null
    },
    "R7": {
     "role": "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
     "longName": "9952156 - Statement - Consolidated statement of changes in equity",
     "shortName": "Consolidated statement of changes in equity",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "",
     "menuCat": "Statements",
     "order": "7",
     "firstAnchor": {
      "contextRef": "c-4476",
      "name": "ifrs-full:Equity",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4451",
      "name": "ifrs-full:IncreaseDecreaseThroughOtherContributionsByOwners",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R8": {
     "role": "http://www.home.barclays/role/Consolidatedcashflowstatement",
     "longName": "9952157 - Statement - Consolidated cash flow statement",
     "shortName": "Consolidated cash flow statement",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "",
     "menuCat": "Statements",
     "order": "8",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ProfitLossBeforeTax",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:OtherInflowsOutflowsOfCashClassifiedAsInvestingActivities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R9": {
     "role": "http://www.home.barclays/role/ConsolidatedcashflowstatementParenthetical",
     "longName": "9952158 - Statement - Consolidated cash flow statement (Parenthetical)",
     "shortName": "Consolidated cash flow statement (Parenthetical)",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "parenthetical",
     "menuCat": "Statements",
     "order": "9",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:InterestReceivedClassifiedAsOperatingActivities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": null
    },
    "R10": {
     "role": "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
     "longName": "9952159 - Statement - Parent company accounts - balance sheet",
     "shortName": "Parent company accounts - balance sheet",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "parenthetical",
     "menuCat": "Statements",
     "order": "10",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:CashAndBankBalancesAtCentralBanks",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4480",
      "name": "ifrs-full:BankAcceptanceAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R11": {
     "role": "http://www.home.barclays/role/ParentcompanyaccountsbalancesheetParenthetical",
     "longName": "9952160 - Statement - Parent company accounts - balance sheet (Parenthetical)",
     "shortName": "Parent company accounts - balance sheet (Parenthetical)",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "parenthetical",
     "menuCat": "Statements",
     "order": "11",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ProfitLoss",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": null
    },
    "R12": {
     "role": "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity",
     "longName": "9952161 - Statement - Parent company accounts - Statement of changes in equity",
     "shortName": "Parent company accounts - Statement of changes in equity",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "parenthetical",
     "menuCat": "Statements",
     "order": "12",
     "firstAnchor": {
      "contextRef": "c-4476",
      "name": "ifrs-full:Equity",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4506",
      "name": "ifrs-full:Equity",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R13": {
     "role": "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequityParenthetical",
     "longName": "9952162 - Statement - Parent company accounts - Statement of changes in equity (Parenthetical)",
     "shortName": "Parent company accounts - Statement of changes in equity (Parenthetical)",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "parenthetical",
     "menuCat": "Statements",
     "order": "13",
     "firstAnchor": {
      "contextRef": "c-4480",
      "name": "ifrs-full:AmountsPayableRelatedPartyTransactions",
      "unitRef": "usd",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-9",
      "ancestors": [
       "span",
       "link:footnote",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": null
    },
    "R14": {
     "role": "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement",
     "longName": "9952163 - Statement - Parent company accounts - Cash flow statement",
     "shortName": "Parent company accounts - Cash flow statement",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "parenthetical",
     "menuCat": "Statements",
     "order": "14",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ProfitLossBeforeTax",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4488",
      "name": "ifrs-full:AdjustmentsForImpairmentLossesReversalOfImpairmentLossesRecognisedInProfitOrLossFinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R15": {
     "role": "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatementParenthetical",
     "longName": "9952164 - Statement - Parent company accounts - Cash flow statement (Parenthetical)",
     "shortName": "Parent company accounts - Cash flow statement (Parenthetical)",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "parenthetical",
     "menuCat": "Statements",
     "order": "15",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:InterestReceivedClassifiedAsOperatingActivities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4488",
      "name": "ifrs-full:InterestReceivedClassifiedAsOperatingActivities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R16": {
     "role": "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
     "longName": "9952165 - Statement - Parent company accounts - Income statement",
     "shortName": "Parent company accounts - Income statement",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "parenthetical",
     "menuCat": "Statements",
     "order": "16",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:InterestRevenueCalculatedUsingEffectiveInterestMethod",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfNetInterestIncomeTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4488",
      "name": "ifrs-full:InterestRevenueCalculatedUsingEffectiveInterestMethod",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R17": {
     "role": "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome",
     "longName": "9952166 - Statement - Parent company accounts - Statement of comprehensive income",
     "shortName": "Parent company accounts - Statement of comprehensive income",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "parenthetical",
     "menuCat": "Statements",
     "order": "17",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ProfitLoss",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4488",
      "name": "ifrs-full:GainsLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTax",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R18": {
     "role": "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincomeParenthetical",
     "longName": "9952168 - Statement - Parent company accounts - Statement of comprehensive income (Parenthetical)",
     "shortName": "Parent company accounts - Statement of comprehensive income (Parenthetical)",
     "isDefault": "false",
     "groupType": "statement",
     "subGroupType": "parenthetical",
     "menuCat": "Statements",
     "order": "18",
     "firstAnchor": {
      "contextRef": "c-4488",
      "name": "ifrs-full:DividendsPaidToEquityHoldersOfParentClassifiedAsFinancingActivities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4488",
      "name": "ifrs-full:DividendsPaidToEquityHoldersOfParentClassifiedAsFinancingActivities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R19": {
     "role": "http://www.home.barclays/role/RiskManagement",
     "longName": "9952169 - Disclosure - Risk Management",
     "shortName": "Risk Management",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "19",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfObjectivesPoliciesAndProcessesForManagingCapitalExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfObjectivesPoliciesAndProcessesForManagingCapitalExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R20": {
     "role": "http://www.home.barclays/role/Materialaccountingpolicies",
     "longName": "9952170 - Disclosure - Material accounting policies",
     "shortName": "Material accounting policies",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "20",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfMaterialAccountingPolicyInformationExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfMaterialAccountingPolicyInformationExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R21": {
     "role": "http://www.home.barclays/role/Segmentalreporting",
     "longName": "9952171 - Disclosure - Segmental reporting",
     "shortName": "Segmental reporting",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "21",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfEntitysReportableSegmentsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfEntitysReportableSegmentsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R22": {
     "role": "http://www.home.barclays/role/Netinterestincome",
     "longName": "9952172 - Disclosure - Net interest income",
     "shortName": "Net interest income",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "22",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfInterestIncomeExpenseExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfInterestIncomeExpenseExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R23": {
     "role": "http://www.home.barclays/role/Netfeeandcommissionincome",
     "longName": "9952173 - Disclosure - Net fee and commission income",
     "shortName": "Net fee and commission income",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "23",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFeeAndCommissionIncomeExpenseExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFeeAndCommissionIncomeExpenseExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R24": {
     "role": "http://www.home.barclays/role/Nettradingincome",
     "longName": "9952174 - Disclosure - Net trading income",
     "shortName": "Net trading income",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "24",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfTradingIncomeExpenseExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfTradingIncomeExpenseExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R25": {
     "role": "http://www.home.barclays/role/Netinvestmentexpenseincome",
     "longName": "9952175 - Disclosure - Net investment (expense)/income",
     "shortName": "Net investment (expense)/income",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "25",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinanceIncomeExpenseExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinanceIncomeExpenseExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R26": {
     "role": "http://www.home.barclays/role/Infrastructureadministrationandgeneralexpenses",
     "longName": "9952176 - Disclosure - Infrastructure, administration and general expenses",
     "shortName": "Infrastructure, administration and general expenses",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "26",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfExpensesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfExpensesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R27": {
     "role": "http://www.home.barclays/role/Creditimpairmentchargesreleases",
     "longName": "9952177 - Disclosure - Credit impairment charges/(releases)",
     "shortName": "Credit impairment charges/(releases)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "27",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfImpairmentOfAssetsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfImpairmentOfAssetsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R28": {
     "role": "http://www.home.barclays/role/Tax",
     "longName": "9952178 - Disclosure - Tax",
     "shortName": "Tax",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "28",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfIncomeTaxExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfIncomeTaxExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R29": {
     "role": "http://www.home.barclays/role/Dividendsonordinarysharesandpreferenceshares",
     "longName": "9952179 - Disclosure - Dividends on ordinary shares and preference shares",
     "shortName": "Dividends on ordinary shares and preference shares",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "29",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfDividendsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfDividendsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R30": {
     "role": "http://www.home.barclays/role/Tradingportfolio",
     "longName": "9952180 - Disclosure - Trading portfolio",
     "shortName": "Trading portfolio",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "30",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialInstrumentsHeldForTradingExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialInstrumentsHeldForTradingExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R31": {
     "role": "http://www.home.barclays/role/Financialassetsatfairvaluethroughtheincomestatement",
     "longName": "9952181 - Disclosure - Financial assets at fair value through the income statement",
     "shortName": "Financial assets at fair value through the income statement",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "31",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialInstrumentsAtFairValueThroughProfitOrLossExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialInstrumentsAtFairValueThroughProfitOrLossExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R32": {
     "role": "http://www.home.barclays/role/Derivativefinancialinstruments",
     "longName": "9952182 - Disclosure - Derivative financial instruments",
     "shortName": "Derivative financial instruments",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "32",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfDerivativeFinancialInstrumentsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfDerivativeFinancialInstrumentsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R33": {
     "role": "http://www.home.barclays/role/Financialassetsatfairvaluethroughothercomprehensiveincome",
     "longName": "9952183 - Disclosure - Financial assets at fair value through other comprehensive income",
     "shortName": "Financial assets at fair value through other comprehensive income",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "33",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialAssetsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialAssetsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R34": {
     "role": "http://www.home.barclays/role/Financialliabilitiesdesignatedatfairvalue",
     "longName": "9952184 - Disclosure - Financial liabilities designated at fair value",
     "shortName": "Financial liabilities designated at fair value",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "34",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialLiabilitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialLiabilitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R35": {
     "role": "http://www.home.barclays/role/Fairvalueoffinancialinstruments",
     "longName": "9952185 - Disclosure - Fair value of financial instruments",
     "shortName": "Fair value of financial instruments",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "35",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFairValueOfFinancialInstrumentsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFairValueOfFinancialInstrumentsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R36": {
     "role": "http://www.home.barclays/role/Offsettingfinancialassetsandfinancialliabilities",
     "longName": "9952186 - Disclosure - Offsetting financial assets and financial liabilities",
     "shortName": "Offsetting financial assets and financial liabilities",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "36",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R37": {
     "role": "http://www.home.barclays/role/Propertyplantandequipment",
     "longName": "9952187 - Disclosure - Property, plant and equipment",
     "shortName": "Property, plant and equipment",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "37",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfPropertyPlantAndEquipmentExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfPropertyPlantAndEquipmentExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R38": {
     "role": "http://www.home.barclays/role/Leases",
     "longName": "9952188 - Disclosure - Leases",
     "shortName": "Leases",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "38",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfLeasesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfLeasesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R39": {
     "role": "http://www.home.barclays/role/Goodwillandintangibleassets",
     "longName": "9952189 - Disclosure - Goodwill and intangible assets",
     "shortName": "Goodwill and intangible assets",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "39",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfIntangibleAssetsAndGoodwillExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfIntangibleAssetsAndGoodwillExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R40": {
     "role": "http://www.home.barclays/role/Otherliabilities",
     "longName": "9952190 - Disclosure - Other liabilities",
     "shortName": "Other liabilities",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "40",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfAccruedExpensesAndOtherLiabilitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfAccruedExpensesAndOtherLiabilitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R41": {
     "role": "http://www.home.barclays/role/Provisions",
     "longName": "9952191 - Disclosure - Provisions",
     "shortName": "Provisions",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "41",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfProvisionsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfProvisionsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R42": {
     "role": "http://www.home.barclays/role/Contingentliabilitiesandcommitments",
     "longName": "9952192 - Disclosure - Contingent liabilities and commitments",
     "shortName": "Contingent liabilities and commitments",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "42",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfCommitmentsAndContingentLiabilitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfCommitmentsAndContingentLiabilitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R43": {
     "role": "http://www.home.barclays/role/Legalcompetitionandregulatorymatters",
     "longName": "9952193 - Disclosure - Legal, competition and regulatory matters",
     "shortName": "Legal, competition and regulatory matters",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "43",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfCommitmentsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfCommitmentsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R44": {
     "role": "http://www.home.barclays/role/Subordinatedliabilities",
     "longName": "9952194 - Disclosure - Subordinated liabilities",
     "shortName": "Subordinated liabilities",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "44",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfSubordinatedLiabilitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfSubordinatedLiabilitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R45": {
     "role": "http://www.home.barclays/role/Ordinarysharespreferencesharesandotherequity",
     "longName": "9952195 - Disclosure - Ordinary shares, preference shares and other equity",
     "shortName": "Ordinary shares, preference shares and other equity",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "45",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfIssuedCapitalExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfIssuedCapitalExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R46": {
     "role": "http://www.home.barclays/role/Reserves",
     "longName": "9952196 - Disclosure - Reserves",
     "shortName": "Reserves",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "46",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfReservesAndOtherEquityInterestExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfReservesAndOtherEquityInterestExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R47": {
     "role": "http://www.home.barclays/role/Staffcosts",
     "longName": "9952197 - Disclosure - Staff costs",
     "shortName": "Staff costs",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "47",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfShortTermEmployeeBenefitsExplanatoryTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfShortTermEmployeeBenefitsExplanatoryTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R48": {
     "role": "http://www.home.barclays/role/Sharebasedpayments",
     "longName": "9952198 - Disclosure - Share-based payments",
     "shortName": "Share-based payments",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "48",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfSharebasedPaymentArrangementsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfSharebasedPaymentArrangementsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R49": {
     "role": "http://www.home.barclays/role/Retirementbenefits",
     "longName": "9952199 - Disclosure - Retirement benefits",
     "shortName": "Retirement benefits",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "49",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfEmployeeBenefitsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfEmployeeBenefitsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R50": {
     "role": "http://www.home.barclays/role/Principalsubsidiaries",
     "longName": "9952200 - Disclosure - Principal subsidiaries",
     "shortName": "Principal subsidiaries",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "50",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfSignificantInvestmentsInSubsidiariesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfSignificantInvestmentsInSubsidiariesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R51": {
     "role": "http://www.home.barclays/role/Structuredentities",
     "longName": "9952201 - Disclosure - Structured entities",
     "shortName": "Structured entities",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "51",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfInformationAboutInterestsInStructuredEntityExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfInformationAboutInterestsInStructuredEntityExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R52": {
     "role": "http://www.home.barclays/role/Investmentsinassociatesandjointventures",
     "longName": "9952202 - Disclosure - Investments in associates and joint ventures",
     "shortName": "Investments in associates and joint ventures",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "52",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfInvestmentsInAssociatesAndJointVenturesTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfInvestmentsInAssociatesAndJointVenturesTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R53": {
     "role": "http://www.home.barclays/role/Securitisations",
     "longName": "9952203 - Disclosure - Securitisations",
     "shortName": "Securitisations",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "53",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfTransfersOfFinancialAssetsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfTransfersOfFinancialAssetsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R54": {
     "role": "http://www.home.barclays/role/Assetspledgedcollateralreceivedandassetstransferred",
     "longName": "9952204 - Disclosure - Assets pledged, collateral received and assets transferred",
     "shortName": "Assets pledged, collateral received and assets transferred",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "54",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfCollateralExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfCollateralExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R55": {
     "role": "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremuneration",
     "longName": "9952205 - Disclosure - Related party transactions and Directors' remuneration",
     "shortName": "Related party transactions and Directors' remuneration",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "55",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfRelatedPartyExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfRelatedPartyExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R56": {
     "role": "http://www.home.barclays/role/AcquisitionandDisposalsofsubsidiaries",
     "longName": "9952206 - Disclosure - Acquisition and Disposals of subsidiaries",
     "shortName": "Acquisition and Disposals of subsidiaries",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "56",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfDisposalOfBusinessesAndDiscontinuedOperationsTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfDisposalOfBusinessesAndDiscontinuedOperationsTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R57": {
     "role": "http://www.home.barclays/role/Auditorsremuneration",
     "longName": "9952207 - Disclosure - Auditor's remuneration",
     "shortName": "Auditor's remuneration",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "57",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfAuditorsRemunerationExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfAuditorsRemunerationExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R58": {
     "role": "http://www.home.barclays/role/Assetsandliabilitiesincludedindisposalgroupclassifiedasheldforsale",
     "longName": "9952208 - Disclosure - Assets and liabilities included in disposal group classified as held for sale",
     "shortName": "Assets and liabilities included in disposal group classified as held for sale",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "58",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R59": {
     "role": "http://www.home.barclays/role/RelatedUndertaking",
     "longName": "9952209 - Disclosure - Related Undertaking",
     "shortName": "Related Undertaking",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "59",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfInterestsInOtherEntitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfInterestsInOtherEntitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R60": {
     "role": "http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc",
     "longName": "995447 - Disclosure - Insider Trading Policies and Procedures",
     "shortName": "Insider Trading Policies and Procedures",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "60",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ecd:InsiderTrdPoliciesProcAdoptedFlag",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ecd:InsiderTrdPoliciesProcAdoptedFlag",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R61": {
     "role": "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure",
     "longName": "995550 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure",
     "shortName": "Cybersecurity Risk Management and Strategy Disclosure",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "",
     "menuCat": "Notes",
     "order": "61",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "cyd:CybersecurityRiskManagementProcessesForAssessingIdentifyingAndManagingThreatsTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "cyd:CybersecurityRiskManagementProcessesForAssessingIdentifyingAndManagingThreatsTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R62": {
     "role": "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies",
     "longName": "9955511 - Disclosure - Material accounting policies (Policies)",
     "shortName": "Material accounting policies (Policies)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "policies",
     "menuCat": "Policies",
     "order": "62",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:StatementOfIFRSCompliance",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:StatementOfIFRSCompliance",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R63": {
     "role": "http://www.home.barclays/role/RiskManagementTables",
     "longName": "9955512 - Disclosure - Risk Management (Tables)",
     "shortName": "Risk Management (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "63",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:SummaryQuantitativeDataAboutEntitysExposureToRisk",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:SummaryQuantitativeDataAboutEntitysExposureToRisk",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R64": {
     "role": "http://www.home.barclays/role/SegmentalreportingTables",
     "longName": "9955513 - Disclosure - Segmental reporting (Tables)",
     "shortName": "Segmental reporting (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "64",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfOperatingSegmentsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfOperatingSegmentsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R65": {
     "role": "http://www.home.barclays/role/NetinterestincomeTables",
     "longName": "9955514 - Disclosure - Net interest income (Tables)",
     "shortName": "Net interest income (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "65",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfNetInterestIncomeTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfNetInterestIncomeTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R66": {
     "role": "http://www.home.barclays/role/NetfeeandcommissionincomeTables",
     "longName": "9955515 - Disclosure - Net fee and commission income (Tables)",
     "shortName": "Net fee and commission income (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "66",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R67": {
     "role": "http://www.home.barclays/role/NettradingincomeTables",
     "longName": "9955516 - Disclosure - Net trading income (Tables)",
     "shortName": "Net trading income (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "67",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfNetTradingIncomeTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfNetTradingIncomeTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R68": {
     "role": "http://www.home.barclays/role/NetinvestmentexpenseincomeTables",
     "longName": "9955517 - Disclosure - Net investment (expense)/income (Tables)",
     "shortName": "Net investment (expense)/income (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "68",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfNetInvestmentIncomeTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfNetInvestmentIncomeTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R69": {
     "role": "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesTables",
     "longName": "9955518 - Disclosure - Infrastructure, administration and general expenses (Tables)",
     "shortName": "Infrastructure, administration and general expenses (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "69",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfExpensesByNatureExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfExpensesByNatureExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R70": {
     "role": "http://www.home.barclays/role/CreditimpairmentchargesreleasesTables",
     "longName": "9955519 - Disclosure - Credit impairment charges/(releases) (Tables)",
     "shortName": "Credit impairment charges/(releases) (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "70",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfImpairmentLossAndReversalOfImpairmentLossExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfImpairmentLossAndReversalOfImpairmentLossExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R71": {
     "role": "http://www.home.barclays/role/TaxTables",
     "longName": "9955520 - Disclosure - Tax (Tables)",
     "shortName": "Tax (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "71",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfComponentsOfIncomeTaxTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfComponentsOfIncomeTaxTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R72": {
     "role": "http://www.home.barclays/role/TradingportfolioTables",
     "longName": "9955521 - Disclosure - Trading portfolio (Tables)",
     "shortName": "Trading portfolio (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "72",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialAssetsHeldForTradingExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialAssetsHeldForTradingExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R73": {
     "role": "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementTables",
     "longName": "9955522 - Disclosure - Financial assets at fair value through the income statement (Tables)",
     "shortName": "Financial assets at fair value through the income statement (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "73",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialInstrumentsDesignatedAtFairValueThroughProfitOrLossExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfCreditRiskExposureExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R74": {
     "role": "http://www.home.barclays/role/DerivativefinancialinstrumentsTables",
     "longName": "9955523 - Disclosure - Derivative financial instruments (Tables)",
     "shortName": "Derivative financial instruments (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "74",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfSummaryOfDerivativeAssetsAndLiabilitiesTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfSummaryOfDerivativeAssetsAndLiabilitiesTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R75": {
     "role": "http://www.home.barclays/role/FinancialassetsatfairvaluethroughothercomprehensiveincomeTables",
     "longName": "9955524 - Disclosure - Financial assets at fair value through other comprehensive income (Tables)",
     "shortName": "Financial assets at fair value through other comprehensive income (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "75",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfAnalysisOfOtherComprehensiveIncomeByItemExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfAnalysisOfOtherComprehensiveIncomeByItemExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R76": {
     "role": "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueTables",
     "longName": "9955525 - Disclosure - Financial liabilities designated at fair value (Tables)",
     "shortName": "Financial liabilities designated at fair value (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "76",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialInstrumentsDesignatedAtFairValueThroughProfitOrLossExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": null
    },
    "R77": {
     "role": "http://www.home.barclays/role/FairvalueoffinancialinstrumentsTables",
     "longName": "9955526 - Disclosure - Fair value of financial instruments (Tables)",
     "shortName": "Fair value of financial instruments (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "77",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFairValueMeasurementExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFairValueMeasurementExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R78": {
     "role": "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesTables",
     "longName": "9955527 - Disclosure - Offsetting financial assets and financial liabilities (Tables)",
     "shortName": "Offsetting financial assets and financial liabilities (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "78",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfOffsettingOfFinancialAssetsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "ifrs-full:DisclosureOfOffsettingOfFinancialLiabilitiesExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfOffsettingOfFinancialAssetsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "ifrs-full:DisclosureOfOffsettingOfFinancialLiabilitiesExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R79": {
     "role": "http://www.home.barclays/role/PropertyplantandequipmentTables",
     "longName": "9955528 - Disclosure - Property, plant and equipment (Tables)",
     "shortName": "Property, plant and equipment (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "79",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfDetailedInformationAboutPropertyPlantAndEquipmentExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfDetailedInformationAboutPropertyPlantAndEquipmentExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R80": {
     "role": "http://www.home.barclays/role/LeasesTables",
     "longName": "9955529 - Disclosure - Leases (Tables)",
     "shortName": "Leases (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "80",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfAdditionalInformationAboutLeasingActivitiesForLesseeExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfAdditionalInformationAboutLeasingActivitiesForLesseeExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R81": {
     "role": "http://www.home.barclays/role/GoodwillandintangibleassetsTables",
     "longName": "9955530 - Disclosure - Goodwill and intangible assets (Tables)",
     "shortName": "Goodwill and intangible assets (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "81",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfDetailedInformationAboutIntangibleAssetsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfDetailedInformationAboutIntangibleAssetsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R82": {
     "role": "http://www.home.barclays/role/OtherliabilitiesTables",
     "longName": "9955531 - Disclosure - Other liabilities (Tables)",
     "shortName": "Other liabilities (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "82",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfOtherLiabilitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfOtherLiabilitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R83": {
     "role": "http://www.home.barclays/role/ProvisionsTables",
     "longName": "9955532 - Disclosure - Provisions (Tables)",
     "shortName": "Provisions (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "83",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfOtherProvisionsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfOtherProvisionsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R84": {
     "role": "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsTables",
     "longName": "9955533 - Disclosure - Contingent liabilities and commitments (Tables)",
     "shortName": "Contingent liabilities and commitments (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "84",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfCommitmentsAndContingentLiabilitiesTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfCommitmentsAndContingentLiabilitiesTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R85": {
     "role": "http://www.home.barclays/role/SubordinatedliabilitiesTables",
     "longName": "9955534 - Disclosure - Subordinated liabilities (Tables)",
     "shortName": "Subordinated liabilities (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "85",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfDetailedInformationAboutBorrowingsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfDetailedInformationAboutBorrowingsExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R86": {
     "role": "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityTables",
     "longName": "9955535 - Disclosure - Ordinary shares, preference shares and other equity (Tables)",
     "shortName": "Ordinary shares, preference shares and other equity (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "86",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfClassesOfShareCapitalExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfClassesOfShareCapitalExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R87": {
     "role": "http://www.home.barclays/role/ReservesTables",
     "longName": "9955536 - Disclosure - Reserves (Tables)",
     "shortName": "Reserves (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "87",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfReservesWithinEquityTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfReservesWithinEquityTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R88": {
     "role": "http://www.home.barclays/role/StaffcostsTables",
     "longName": "9955537 - Disclosure - Staff costs (Tables)",
     "shortName": "Staff costs (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "88",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:ScheduleOfShortTermEmployeeBenefitsExplanatoryTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:ScheduleOfShortTermEmployeeBenefitsExplanatoryTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R89": {
     "role": "http://www.home.barclays/role/SharebasedpaymentsTables",
     "longName": "9955538 - Disclosure - Share-based payments (Tables)",
     "shortName": "Share-based payments (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "89",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R90": {
     "role": "http://www.home.barclays/role/RetirementbenefitsTables",
     "longName": "9955539 - Disclosure - Retirement benefits (Tables)",
     "shortName": "Retirement benefits (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "90",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:NetPensionCostTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:NetPensionCostTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R91": {
     "role": "http://www.home.barclays/role/PrincipalsubsidiariesTables",
     "longName": "9955540 - Disclosure - Principal subsidiaries (Tables)",
     "shortName": "Principal subsidiaries (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "91",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfInformationAboutConsolidatedStructuredEntitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfInformationAboutConsolidatedStructuredEntitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R92": {
     "role": "http://www.home.barclays/role/StructuredentitiesTables",
     "longName": "9955541 - Disclosure - Structured entities (Tables)",
     "shortName": "Structured entities (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "92",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfUnconsolidatedStructuredEntitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfUnconsolidatedStructuredEntitiesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R93": {
     "role": "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresTables",
     "longName": "9955542 - Disclosure - Investments in associates and joint ventures (Tables)",
     "shortName": "Investments in associates and joint ventures (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "93",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DetailedInformationAboutInvestmentsInAssociatesAndJointVenturesTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DetailedInformationAboutInvestmentsInAssociatesAndJointVenturesTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R94": {
     "role": "http://www.home.barclays/role/SecuritisationsTables",
     "longName": "9955543 - Disclosure - Securitisations (Tables)",
     "shortName": "Securitisations (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "94",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R95": {
     "role": "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredTables",
     "longName": "9955544 - Disclosure - Assets pledged, collateral received and assets transferred (Tables)",
     "shortName": "Assets pledged, collateral received and assets transferred (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "95",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfCarryingAmountOfTheAssetsPledgedAndAssetsTransferredAsSecurityAgainstLiabilitiesTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfCarryingAmountOfTheAssetsPledgedAndAssetsTransferredAsSecurityAgainstLiabilitiesTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R96": {
     "role": "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationTables",
     "longName": "9955545 - Disclosure - Related party transactions and Directors' remuneration (Tables)",
     "shortName": "Related party transactions and Directors' remuneration (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "96",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfGroupsFinancialStatementsByCategoryTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfGroupsFinancialStatementsByCategoryTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R97": {
     "role": "http://www.home.barclays/role/AuditorsremunerationTables",
     "longName": "9955546 - Disclosure - Auditor's remuneration (Tables)",
     "shortName": "Auditor's remuneration (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "97",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfDetailedInformationAboutAuditorsRemunerationTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfDetailedInformationAboutAuditorsRemunerationTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R98": {
     "role": "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleTables",
     "longName": "9955547 - Disclosure - Assets and liabilities included in disposal group classified as held for sale (Tables)",
     "shortName": "Assets and liabilities included in disposal group classified as held for sale (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "98",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:DisclosureOfAssetsAndLiabilitiesClassifiedAsHeldForSaleTableTextBlock",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": null
    },
    "R99": {
     "role": "http://www.home.barclays/role/RelatedUndertakingsTables",
     "longName": "9955548 - Disclosure - Related Undertakings (Tables)",
     "shortName": "Related Undertakings (Tables)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "tables",
     "menuCat": "Tables",
     "order": "99",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfInterestsInSubsidiariesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DisclosureOfInterestsInSubsidiariesExplanatory",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R100": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
     "longName": "9955549 - Disclosure - Risk Management - Disclosure of maximum exposure and effects of collateral and other credit enhancements (Details)",
     "shortName": "Risk Management - Disclosure of maximum exposure and effects of collateral and other credit enhancements (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "100",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-39",
      "name": "ifrs-full:NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ifrs-full:SummaryQuantitativeDataAboutEntitysExposureToRisk",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R101": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
     "longName": "9955550 - Disclosure - Risk Management - Disclosure of loans and advances at amortised cost by product (Details)",
     "shortName": "Risk Management - Disclosure of loans and advances at amortised cost by product (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "101",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-229",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R102": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
     "longName": "9955551 - Disclosure - Risk Management - Disclosure of movement in gross exposures and impairment allowance including reconciliation of ECL (Details)",
     "shortName": "Risk Management - Disclosure of movement in gross exposures and impairment allowance including reconciliation of ECL (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "102",
     "firstAnchor": {
      "contextRef": "c-1105",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-637",
      "name": "bbplc:IncreaseDecreaseThroughRecoveriesAndReimbursementsFinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R103": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
     "longName": "9955552 - Disclosure - Risk Management - Disclosure of movement in gross exposure for loan commitment and financial guarantees (Details)",
     "shortName": "Risk Management - Disclosure of movement in gross exposure for loan commitment and financial guarantees (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "103",
     "firstAnchor": {
      "contextRef": "c-700",
      "name": "ifrs-full:IncreaseDecreaseThroughTransfersExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-700",
      "name": "ifrs-full:IncreaseDecreaseThroughTransfersExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R104": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
     "longName": "9955553 - Disclosure - Risk Management - Disclosure of management adjustments to models for impairment and Economic uncertainty management adjustments by stage (Details)",
     "shortName": "Risk Management - Disclosure of management adjustments to models for impairment and Economic uncertainty management adjustments by stage (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "104",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1110",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-8",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R105": {
     "role": "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails",
     "longName": "9955554 - Disclosure - Risk Management - Economic uncertainty adjustments and Other adjustments (Details)",
     "shortName": "Risk Management - Economic uncertainty adjustments and Other adjustments (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "105",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": null
    },
    "R106": {
     "role": "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails",
     "longName": "9955555 - Disclosure - Risk Management - Measurement uncertainty and sensitivity analysis (Details)",
     "shortName": "Risk Management - Measurement uncertainty and sensitivity analysis (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "106",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "bbplc:TotalNumberOfEconomicScenariosToCalculateECLAsAPercentage",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "INF",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "bbplc:TotalNumberOfEconomicScenariosToCalculateECLAsAPercentage",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "INF",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R107": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
     "longName": "9955556 - Disclosure - Risk Management - Disclosure of macroeconomic variables used in the calculation of ECL and Scenario probability weighting (Details)",
     "shortName": "Risk Management - Disclosure of macroeconomic variables used in the calculation of ECL and Scenario probability weighting (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "107",
     "firstAnchor": {
      "contextRef": "c-1548",
      "name": "bbplc:ScenarioWeighting",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "3",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1548",
      "name": "bbplc:ScenarioWeighting",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "3",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R108": {
     "role": "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
     "longName": "9955557 - Disclosure - Risk Management - ECL under 100% weighted scenarios for modelled portfolios (Details)",
     "shortName": "Risk Management - ECL under 100% weighted scenarios for modelled portfolios (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "108",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:ExpectedCreditLossRate",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "INF",
      "ancestors": [
       "span",
       "ix:continuation",
       "ifrs-full:ExplanationOfInputsAssumptionsAndEstimationTechniquesUsedToApplyImpairmentRequirementsExplanatory",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1971",
      "name": "bbplc:WeightedExpectedCreditLossUpliftPercentage",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "3",
      "ancestors": [
       "span",
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R109": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
     "longName": "9955558 - Disclosure - Risk Management - Disclosure of ECL under 100% weighted scenarios for key modelled portfolios (Details)",
     "shortName": "Risk Management - Disclosure of ECL under 100% weighted scenarios for key modelled portfolios (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "109",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1956",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R110": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
     "longName": "9955559 - Disclosure - Risk Management - Disclosure of concentrations of credit risk by industry and geography (Details)",
     "shortName": "Risk Management - Disclosure of concentrations of credit risk by industry and geography (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "110",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-2308",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R111": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
     "longName": "9955560 - Disclosure - Risk Management - Disclosure of Balance Sheet credit quality (Details)",
     "shortName": "Risk Management - Disclosure of Balance Sheet credit quality (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "111",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:CashAndBankBalancesAtCentralBanks",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-2417",
      "name": "ifrs-full:CashAndBankBalancesAtCentralBanks",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "bbplc:DisclosureOfCreditQualityOfAssetsExposedToCreditRiskTextBlock",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R112": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
     "longName": "9955561 - Disclosure - Risk Management - Disclosure of analysis of credit risk profile by internal PD band for loans and advances at amortised cost, contingent liabilities and loan commitments (Details)",
     "shortName": "Risk Management - Disclosure of analysis of credit risk profile by internal PD band for loans and advances at amortised cost, contingent liabilities and loan commitments (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "112",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-3334",
      "name": "ifrs-full:ExpectedCreditLossRate",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "3",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R113": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
     "longName": "9955562 - Disclosure - Risk Management - Disclosure of assets held for sale (Details)",
     "shortName": "Risk Management - Disclosure of assets held for sale (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "113",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-3637",
      "name": "bbplc:ImpairmentAllowanceCoverageRatio",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "3",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R114": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
     "longName": "9955563 - Disclosure - Risk Management - Disclosure of management adjustments to models for impairment of assets held for sale (Details)",
     "shortName": "Risk Management - Disclosure of management adjustments to models for impairment of assets held for sale (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "114",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-3589",
      "name": "bbplc:ImpairmentAllowanceIncludingLoanCommitmentsAndFinancialGuaranteeContractsPercentage",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "3",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R115": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
     "longName": "9955564 - Disclosure - Risk Management - Disclosure of credit exposures by internal PD grade of assets held for sale (Details)",
     "shortName": "Risk Management - Disclosure of credit exposures by internal PD grade of assets held for sale (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "115",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-3589",
      "name": "ifrs-full:ExpectedCreditLossRate",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "3",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R116": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails",
     "longName": "9955565 - Disclosure - Risk Management - Disclosure of management Value at Risk (Details)",
     "shortName": "Risk Management - Disclosure of management Value at Risk (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "116",
     "firstAnchor": {
      "contextRef": "c-4392",
      "name": "ifrs-full:ValueAtRisk",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4392",
      "name": "ifrs-full:ValueAtRisk",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R117": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
     "longName": "9955566 - Disclosure - Risk Management - Disclosure of contractual maturity of financial assets and liabilities (Details)",
     "shortName": "Risk Management - Disclosure of contractual maturity of financial assets and liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "117",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:CashAndBankBalancesAtCentralBanks",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "bbplc:OtherAssetsIncludingAmountsHeldForSale",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R118": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails",
     "longName": "9955567 - Disclosure - Risk Management - Disclosure of contractual maturity of financial liabilities - undiscounted (Details)",
     "shortName": "Risk Management - Disclosure of contractual maturity of financial liabilities - undiscounted (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "118",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "bbplc:DepositsAtAmortisedCostUndiscountedCashFlows",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "bbplc:DepositsAtAmortisedCostUndiscountedCashFlows",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R119": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails",
     "longName": "9955568 - Disclosure - Risk Management - Disclosure of maturity analysis of off-balance sheet commitments given (Details)",
     "shortName": "Risk Management - Disclosure of maturity analysis of off-balance sheet commitments given (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "119",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:EstimatedFinancialEffectOfContingentLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:MaturityAnalysisOfOffBalanceSheetCommitmentsGivenTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:EstimatedFinancialEffectOfContingentLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:MaturityAnalysisOfOffBalanceSheetCommitmentsGivenTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R120": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails",
     "longName": "9955570 - Disclosure - Risk Management - Disclosure of functional currency of the operation (Details)",
     "shortName": "Risk Management - Disclosure of functional currency of the operation (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "120",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "bbplc:FinancialInstrumentWhichHedgeNetInvestmentsHedges",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-8",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "bbplc:FinancialInstrumentWhichHedgeNetInvestmentsHedges",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-8",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R121": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails",
     "longName": "9955571 - Disclosure - Risk Management - Disclosure of net interest income sensitivity (AEaR) by currency (Details)",
     "shortName": "Risk Management - Disclosure of net interest income sensitivity (AEaR) by currency (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "121",
     "firstAnchor": {
      "contextRef": "c-4435",
      "name": "ifrs-full:IncreaseDecreaseInProfitLossDueToReasonablyPossibleIncreaseInRiskExposureThatArisesFromContractsWithinScopeOfIFRS17",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4427",
      "name": "ifrs-full:IncreaseDecreaseInProfitLossDueToReasonablyPossibleIncreaseInRiskExposureThatArisesFromContractsWithinScopeOfIFRS17",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfSensitivityAnalysisToChangesInRiskExposuresThatAriseFromContractsWithinScopeOfIFRS17Explanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R122": {
     "role": "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails",
     "longName": "9955572 - Disclosure - Risk Management - Disclosure of analysis of equity sensitivity (Details)",
     "shortName": "Risk Management - Disclosure of analysis of equity sensitivity (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "122",
     "firstAnchor": {
      "contextRef": "c-4439",
      "name": "ifrs-full:IncreaseDecreaseInProfitLossDueToReasonablyPossibleIncreaseInRiskExposureThatArisesFromContractsWithinScopeOfIFRS17",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4439",
      "name": "ifrs-full:IncreaseDecreaseInProfitLossDueToReasonablyPossibleIncreaseInRiskExposureThatArisesFromContractsWithinScopeOfIFRS17",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R123": {
     "role": "http://www.home.barclays/role/SegmentalreportingNarrativeDetails",
     "longName": "9955573 - Disclosure - Segmental reporting - Narrative (Details)",
     "shortName": "Segmental reporting - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "123",
     "firstAnchor": {
      "contextRef": "c-4513",
      "name": "bbplc:CorporateClientTurnoverThreshold",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-5",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4513",
      "name": "bbplc:CorporateClientTurnoverThreshold",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-5",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R124": {
     "role": "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails",
     "longName": "9955574 - Disclosure - Segmental reporting - Disclosure of analysis of results by business (Details)",
     "shortName": "Segmental reporting - Disclosure of analysis of results by business (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "124",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:InterestRevenueExpense",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ifrs-full:DisclosureOfOperatingSegmentsExplanatory",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:OtherIncomeExpense",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ifrs-full:DisclosureOfOperatingSegmentsExplanatory",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R125": {
     "role": "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails",
     "longName": "9955575 - Disclosure - Segmental reporting - Disclosure of income by geographic region (Details)",
     "shortName": "Segmental reporting - Disclosure of income by geographic region (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "125",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:OperatingIncome",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4559",
      "name": "bbplc:OperatingIncome",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ifrs-full:DisclosureOfGeographicalAreasExplanatory",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R126": {
     "role": "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails",
     "longName": "9955576 - Disclosure - Net interest income - Summary of net interest income (Details)",
     "shortName": "Net interest income - Summary of net interest income (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "126",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:InterestIncomeOnCashAndBankBalancesAtCentralBanks",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfNetInterestIncomeTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:InterestIncomeOnCashAndBankBalancesAtCentralBanks",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfNetInterestIncomeTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R127": {
     "role": "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
     "longName": "9955577 - Disclosure - Net fee and commission income - Summary of total fees in scope of IFRS 15 Revenues from Contracts with Customers (Details)",
     "shortName": "Net fee and commission income - Summary of total fees in scope of IFRS 15 Revenues from Contracts with Customers (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "127",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:RevenueFromContractsWithCustomers",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:RevenueFromContractsWithCustomers",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R128": {
     "role": "http://www.home.barclays/role/NetfeeandcommissionincomeNarrativeDetails",
     "longName": "9955578 - Disclosure - Net fee and commission income - Narrative (Details)",
     "shortName": "Net fee and commission income - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "128",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:ContractAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:ContractAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R129": {
     "role": "http://www.home.barclays/role/NettradingincomeDetails",
     "longName": "9955579 - Disclosure - Net trading income (Details)",
     "shortName": "Net trading income (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "129",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:TradingIncomeExpense",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4679",
      "name": "ifrs-full:TradingIncomeExpense",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfNetTradingIncomeTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R130": {
     "role": "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails",
     "longName": "9955580 - Disclosure - Net investment (expense)/income (Details)",
     "shortName": "Net investment (expense)/income (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "130",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:GainsLossesOnFinancialAssetsAtFairValueThroughProfitOrLossMandatorilyMeasuredAtFairValue",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfNetInvestmentIncomeTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:GainsLossesOnFinancialAssetsAtFairValueThroughProfitOrLossMandatorilyMeasuredAtFairValue",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfNetInvestmentIncomeTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R131": {
     "role": "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails",
     "longName": "9955581 - Disclosure - Infrastructure, administration and general expenses (Details)",
     "shortName": "Infrastructure, administration and general expenses (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "131",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ChangesInPropertyPlantAndEquipment",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfExpensesByNatureExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ChangesInPropertyPlantAndEquipment",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfExpensesByNatureExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R132": {
     "role": "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
     "longName": "9955582 - Disclosure - Credit impairment charges/(releases) - Narrative (Details)",
     "shortName": "Credit impairment charges/(releases) - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "132",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssetsWrittenOffDuringReportingPeriodAndStillSubjectToEnforcementActivityContractualAmountOutstanding",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssetsWrittenOffDuringReportingPeriodAndStillSubjectToEnforcementActivityContractualAmountOutstanding",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R133": {
     "role": "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
     "longName": "9955583 - Disclosure - Credit impairment charges/(releases) - Disclosure of credit impairment charges and other provisions (Details)",
     "shortName": "Credit impairment charges/(releases) - Disclosure of credit impairment charges and other provisions (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "133",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ImpairmentLossRecognisedInProfitOrLoss",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfImpairmentLossAndReversalOfImpairmentLossExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ImpairmentLossRecognisedInProfitOrLoss",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfImpairmentLossAndReversalOfImpairmentLossExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R134": {
     "role": "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails",
     "longName": "9955584 - Disclosure - Tax - Disclosure of components of income tax (Details)",
     "shortName": "Tax - Disclosure of components of income tax (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "134",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:CurrentTaxExpenseIncome",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfComponentsOfIncomeTaxTableTextBlock",
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:CurrentTaxExpenseIncome",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfComponentsOfIncomeTaxTableTextBlock",
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R135": {
     "role": "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails",
     "longName": "9955585 - Disclosure - Tax - Disclosure of reconciliation between the actual tax charge and the corporate tax rate (Details)",
     "shortName": "Tax - Disclosure of reconciliation between the actual tax charge and the corporate tax rate (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "135",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ProfitLossBeforeTax",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:TaxExpenseIncomeAtApplicableTaxRate",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R136": {
     "role": "http://www.home.barclays/role/TaxNarrativeDetails",
     "longName": "9955586 - Disclosure - Tax - Narrative (Details)",
     "shortName": "Tax - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "136",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:AverageEffectiveTaxRate",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "3",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:CurrentTaxExpenseIncomeRelatedToPillarTwoIncomeTaxes",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R137": {
     "role": "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
     "longName": "9955587 - Disclosure - Tax - Disclosure of deferred tax assets and liabilities (Details)",
     "shortName": "Tax - Disclosure of deferred tax assets and liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "137",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:DeferredTaxAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:DeferredTaxLiabilityAsset",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R138": {
     "role": "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails",
     "longName": "9955588 - Disclosure - Tax - Disclosure of movements on deferred tax assets and liabilities during the year before offsetting (Details)",
     "shortName": "Tax - Disclosure of movements on deferred tax assets and liabilities during the year before offsetting (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "138",
     "firstAnchor": {
      "contextRef": "c-1105",
      "name": "bbplc:DeferredTaxAssetsBeforeOffsetting",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeDeferredTaxAssetLiability",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R139": {
     "role": "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails",
     "longName": "9955589 - Disclosure - Dividends on ordinary shares and preference shares (Details)",
     "shortName": "Dividends on ordinary shares and preference shares (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "139",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DividendsPaidOrdinaryShares",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:DividendsPaidOrdinarySharesPerShare",
      "unitRef": "gbpPerShare",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "2",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R140": {
     "role": "http://www.home.barclays/role/TradingportfolioDetails",
     "longName": "9955590 - Disclosure - Trading portfolio (Details)",
     "shortName": "Trading portfolio (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "140",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4812",
      "name": "ifrs-full:FinancialLiabilitiesAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfFinancialLiabilitiesHeldForTradingExplanatory",
       "ifrs-full:DisclosureOfFinancialAssetsHeldForTradingExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R141": {
     "role": "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails",
     "longName": "9955591 - Disclosure - Financial assets at fair value through the income statement - Disclosure of financial assets designated at fair value (Details)",
     "shortName": "Financial assets at fair value through the income statement - Disclosure of financial assets designated at fair value (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "141",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4820",
      "name": "ifrs-full:LoansAndAdvances",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfFinancialInstrumentsDesignatedAtFairValueThroughProfitOrLossExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R142": {
     "role": "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails",
     "longName": "9955592 - Disclosure - Financial assets at fair value through the income statement - Disclosure of credit risk of loans and advances designated at fair value and related credit derivatives (Details)",
     "shortName": "Financial assets at fair value through the income statement - Disclosure of credit risk of loans and advances designated at fair value and related credit derivatives (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "142",
     "firstAnchor": {
      "contextRef": "c-4824",
      "name": "ifrs-full:AmountByWhichFinancialAssetsRelatedCreditDerivativesOrSimilarInstrumentsMitigateMaximumExposureToCreditRisk",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4824",
      "name": "ifrs-full:AmountByWhichFinancialAssetsRelatedCreditDerivativesOrSimilarInstrumentsMitigateMaximumExposureToCreditRisk",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R143": {
     "role": "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails",
     "longName": "9955593 - Disclosure - Derivative financial instruments - Disclosure of total derivatives (Details)",
     "shortName": "Derivative financial instruments - Disclosure of total derivatives (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "143",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:NotionalAmount",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfSummaryOfDerivativeAssetsAndLiabilitiesTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": null
    },
    "R144": {
     "role": "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
     "longName": "9955594 - Disclosure - Derivative financial instruments - Disclosure of derivatives held for trading and risk management (Details)",
     "shortName": "Derivative financial instruments - Disclosure of derivatives held for trading and risk management (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "144",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:NotionalAmount",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfSummaryOfDerivativeAssetsAndLiabilitiesTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4927",
      "name": "ifrs-full:DerivativeFinancialAssetsHeldForHedging",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R145": {
     "role": "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
     "longName": "9955595 - Disclosure - Derivative financial instruments - Disclosure of hedged items in fair value hedges (Details)",
     "shortName": "Derivative financial instruments - Disclosure of hedged items in fair value hedges (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "145",
     "firstAnchor": {
      "contextRef": "c-4974",
      "name": "ifrs-full:HedgedItemAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ifrs-full:DisclosureOfDetailedInformationAboutHedgedItemsExplanatory",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4974",
      "name": "ifrs-full:HedgedItemAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ifrs-full:DisclosureOfDetailedInformationAboutHedgedItemsExplanatory",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R146": {
     "role": "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
     "longName": "9955596 - Disclosure - Derivative financial instruments - Disclosure of hedging instruments which are carried on the Group's balance sheet, cash flow and net investment hedging (Details)",
     "shortName": "Derivative financial instruments - Disclosure of hedging instruments which are carried on the Group's balance sheet, cash flow and net investment hedging (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "146",
     "firstAnchor": {
      "contextRef": "c-4974",
      "name": "ifrs-full:NominalAmountOfHedgingInstrument",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4983",
      "name": "ifrs-full:GainLossOnChangeInFairValueOfHedgingInstrumentUsedAsBasisForRecognisingHedgeIneffectiveness",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R147": {
     "role": "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
     "longName": "9955597 - Disclosure - Derivative financial instruments - Disclosure of expected notional values of current hedging instruments in future years (Details)",
     "shortName": "Derivative financial instruments - Disclosure of expected notional values of current hedging instruments in future years (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "147",
     "firstAnchor": {
      "contextRef": "c-4974",
      "name": "ifrs-full:NominalAmountOfHedgingInstrument",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5026",
      "name": "ifrs-full:NominalAmountOfHedgingInstrument",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R148": {
     "role": "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
     "longName": "9955598 - Disclosure - Derivative financial instruments - Narrative (Details)",
     "shortName": "Derivative financial instruments - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "148",
     "firstAnchor": {
      "contextRef": "c-5040",
      "name": "bbplc:NumberOfHedges",
      "unitRef": "hedge",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "0",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5040",
      "name": "bbplc:NumberOfHedges",
      "unitRef": "hedge",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "0",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R149": {
     "role": "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
     "longName": "9955599 - Disclosure - Derivative financial instruments - Disclosure of hedged items in cash flow hedges and hedges of net investments in foreign operations (Details)",
     "shortName": "Derivative financial instruments - Disclosure of hedged items in cash flow hedges and hedges of net investments in foreign operations (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "149",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:ReserveOfExchangeDifferencesOnTranslationContinuingHedges",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4751",
      "name": "ifrs-full:GainLossOnChangeInFairValueOfHedgedItemUsedAsBasisForRecognisingHedgeIneffectiveness",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R150": {
     "role": "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails",
     "longName": "9955600 - Disclosure - Derivative financial instruments - Disclosure of hedging instruments which are carried on the Group's balance sheet, fair value hedging (Details)",
     "shortName": "Derivative financial instruments - Disclosure of hedging instruments which are carried on the Group's balance sheet, fair value hedging (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "150",
     "firstAnchor": {
      "contextRef": "c-4760",
      "name": "ifrs-full:NominalAmountOfHedgingInstrument",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4760",
      "name": "ifrs-full:NominalAmountOfHedgingInstrument",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R151": {
     "role": "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails",
     "longName": "9955601 - Disclosure - Derivative financial instruments - Disclosure of effect on the income statement and OCI as a result of hedge accounting (Details)",
     "shortName": "Derivative financial instruments - Disclosure of effect on the income statement and OCI as a result of hedge accounting (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "151",
     "firstAnchor": {
      "contextRef": "c-5126",
      "name": "ifrs-full:ReclassificationAdjustmentsOnHedgesOfNetInvestmentsInForeignOperationsNetOfTax",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5126",
      "name": "ifrs-full:ReclassificationAdjustmentsOnHedgesOfNetInvestmentsInForeignOperationsNetOfTax",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R152": {
     "role": "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectonthereservesasaresultofhedgeaccountingDetails",
     "longName": "9955602 - Disclosure - Derivative financial instruments - Disclosure of effect on the reserves as a result of hedge accounting (Details)",
     "shortName": "Derivative financial instruments - Disclosure of effect on the reserves as a result of hedge accounting (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "152",
     "firstAnchor": {
      "contextRef": "c-1105",
      "name": "ifrs-full:ReserveOfCashFlowHedges",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:GainsLossesOnExchangeDifferencesOnCashFlowHedgesBeforeTax",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R153": {
     "role": "http://www.home.barclays/role/FinancialassetsatfairvaluethroughothercomprehensiveincomeDetails",
     "longName": "9955603 - Disclosure - Financial assets at fair value through other comprehensive income (Details)",
     "shortName": "Financial assets at fair value through other comprehensive income (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "153",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssetsAtFairValueThroughOtherComprehensiveIncome",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1052",
      "name": "ifrs-full:FinancialAssetsAtFairValueThroughOtherComprehensiveIncome",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfAnalysisOfOtherComprehensiveIncomeByItemExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R154": {
     "role": "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails",
     "longName": "9955604 - Disclosure - Financial liabilities designated at fair value - Disclosure of financial liabilities designated at fair value (Details)",
     "shortName": "Financial liabilities designated at fair value - Disclosure of financial liabilities designated at fair value (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "154",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:RepurchaseAgreementsAndCashCollateralOnSecuritiesLent",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5130",
      "name": "ifrs-full:DebtSecurities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R155": {
     "role": "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueNarrativeDetails",
     "longName": "9955605 - Disclosure - Financial liabilities designated at fair value - Narrative (Details)",
     "shortName": "Financial liabilities designated at fair value - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "155",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:AccumulatedChangesInFairValueOfFinancialLiabilityAttributableToChangesInCreditRiskOfLiability",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:AccumulatedChangesInFairValueOfFinancialLiabilityAttributableToChangesInCreditRiskOfLiability",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R156": {
     "role": "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails",
     "longName": "9955606 - Disclosure - Fair value of financial instruments - Narrative (Details)",
     "shortName": "Fair value of financial instruments - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "156",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-8",
      "ancestors": [
       "span",
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-8",
      "ancestors": [
       "span",
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R157": {
     "role": "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
     "longName": "9955607 - Disclosure - Fair value of financial instruments - Disclosure of assets and liabilities held at fair value disaggregated by valuation technique (Details)",
     "shortName": "Fair value of financial instruments - Disclosure of assets and liabilities held at fair value disaggregated by valuation technique (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "157",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4829",
      "name": "ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R158": {
     "role": "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
     "longName": "9955608 - Disclosure - Fair value of financial instruments - Disclosure of Level 3 assets and liabilities held at fair value disaggregated by product type (Details)",
     "shortName": "Fair value of financial instruments - Disclosure of Level 3 assets and liabilities held at fair value disaggregated by product type (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "158",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5146",
      "name": "ifrs-full:DerivativeFinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R159": {
     "role": "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
     "longName": "9955609 - Disclosure - Fair value of financial instruments - Disclosure of analysis of movements in Level 3 assets and liabilities (Details)",
     "shortName": "Fair value of financial instruments - Disclosure of analysis of movements in Level 3 assets and liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "159",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:TransfersIntoLevel3OfFairValueHierarchyAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-8",
      "ancestors": [
       "span",
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5228",
      "name": "ifrs-full:NetAssetsLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R160": {
     "role": "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
     "longName": "9955610 - Disclosure - Fair value of financial instruments - Disclosure of unrealised gains and losses on Level 3 financial assets and liabilities (Details)",
     "shortName": "Fair value of financial instruments - Disclosure of unrealised gains and losses on Level 3 financial assets and liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "160",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:TradingIncomeExpense",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5246",
      "name": "ifrs-full:TradingIncomeExpense",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R161": {
     "role": "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
     "longName": "9955611 - Disclosure - Fair value of financial instruments - Disclosure of significant unobservable inputs (Details)",
     "shortName": "Fair value of financial instruments - Disclosure of significant unobservable inputs (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "161",
     "firstAnchor": {
      "contextRef": "c-5294",
      "name": "bbplc:SignificantUnobservableInputsAssetsAndLiabilities",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "4",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5294",
      "name": "bbplc:SignificantUnobservableInputsAssetsAndLiabilities",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "4",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R162": {
     "role": "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
     "longName": "9955612 - Disclosure - Fair value of financial instruments - Disclosure of sensitivity analysis of valuations using unobservable inputs (Details)",
     "shortName": "Fair value of financial instruments - Disclosure of sensitivity analysis of valuations using unobservable inputs (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "162",
     "firstAnchor": {
      "contextRef": "c-5196",
      "name": "bbplc:IncreaseInFairValueMeasurementDueToChangeInMultipleUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsRecognisedInProfitOrLossAfterTaxAssetsLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5196",
      "name": "bbplc:IncreaseInFairValueMeasurementDueToChangeInMultipleUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsRecognisedInProfitOrLossAfterTaxAssetsLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R163": {
     "role": "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureoffairvalueadjustmentsDetails",
     "longName": "9955613 - Disclosure - Fair value of financial instruments - Disclosure of fair value adjustments (Details)",
     "shortName": "Fair value of financial instruments - Disclosure of fair value adjustments (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "163",
     "firstAnchor": {
      "contextRef": "c-5364",
      "name": "bbplc:AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountAssetsLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": null
    },
    "R164": {
     "role": "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
     "longName": "9955614 - Disclosure - Fair value of financial instruments - Disclosure of comparison of carrying amounts and fair values for assets and liabilities not held at fair value (Details)",
     "shortName": "Fair value of financial instruments - Disclosure of comparison of carrying amounts and fair values for assets and liabilities not held at fair value (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "164",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:DebtInstrumentsHeldAtAmortisedCost",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5387",
      "name": "ifrs-full:DebtInstrumentsHeldAtAmortisedCost",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R165": {
     "role": "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
     "longName": "9955615 - Disclosure - Offsetting financial assets and financial liabilities (Details)",
     "shortName": "Offsetting financial assets and financial liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "165",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:DerivativeFinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfOffsettingOfFinancialAssetsExplanatory",
       "ifrs-full:DisclosureOfOffsettingOfFinancialLiabilitiesExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "bbplc:SettlementsAssetsLiabilitiesOffsetAmounts",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R166": {
     "role": "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails",
     "longName": "9955616 - Disclosure - Property, plant and equipment - Disclosure of depreciation rates (Details)",
     "shortName": "Property, plant and equipment - Disclosure of depreciation rates (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "166",
     "firstAnchor": {
      "contextRef": "c-5420",
      "name": "ifrs-full:DepreciationRatePropertyPlantAndEquipment",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "INF",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5420",
      "name": "ifrs-full:DepreciationRatePropertyPlantAndEquipment",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "INF",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R167": {
     "role": "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails",
     "longName": "9955617 - Disclosure - Property, plant and equipment - Schedule of reconciliation of property, plant and equipment (Details)",
     "shortName": "Property, plant and equipment - Schedule of reconciliation of property, plant and equipment (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "167",
     "firstAnchor": {
      "contextRef": "c-1105",
      "name": "ifrs-full:PropertyPlantAndEquipmentIncludingRightofuseAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfReconciliationOfChangesInPropertyPlantAndEquipmentIncludingRightofuseAssetsExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5466",
      "name": "ifrs-full:PropertyPlantAndEquipmentIncludingRightofuseAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfReconciliationOfChangesInPropertyPlantAndEquipmentIncludingRightofuseAssetsExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R168": {
     "role": "http://www.home.barclays/role/PropertyplantandequipmentNarrativeDetails",
     "longName": "9955618 - Disclosure - Property, plant and equipment - Narrative (Details)",
     "shortName": "Property, plant and equipment - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "168",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:OtherOperatingIncomeExpense",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5486",
      "name": "ifrs-full:OtherOperatingIncomeExpense",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R169": {
     "role": "http://www.home.barclays/role/LeasesDisclosureofleaseliabilitiesDetails",
     "longName": "9955619 - Disclosure - Leases - Disclosure of lease liabilities (Details)",
     "shortName": "Leases - Disclosure of lease liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "169",
     "firstAnchor": {
      "contextRef": "c-1105",
      "name": "ifrs-full:LeaseLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfAdditionalInformationAboutLeasingActivitiesForLesseeExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4468",
      "name": "ifrs-full:LeaseLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfAdditionalInformationAboutLeasingActivitiesForLesseeExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R170": {
     "role": "http://www.home.barclays/role/LeasesDisclosureofmaturityanalysisofleaseliabilitiesDetails",
     "longName": "9955620 - Disclosure - Leases - Disclosure of maturity analysis of lease liabilities (Details)",
     "shortName": "Leases - Disclosure of maturity analysis of lease liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "170",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:GrossLeaseLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:GrossLeaseLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R171": {
     "role": "http://www.home.barclays/role/LeasesNarrativeDetails",
     "longName": "9955621 - Disclosure - Leases - Narrative (Details)",
     "shortName": "Leases - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "171",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:LeaseExtensionPeriod",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "bbplc:NumberOfLeasesWithVariableLeasePaymentTerms",
      "unitRef": "lease",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "INF",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R172": {
     "role": "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
     "longName": "9955622 - Disclosure - Goodwill and intangible assets - Disclosure of amortisation periods for goodwill and intangible assets (Details)",
     "shortName": "Goodwill and intangible assets - Disclosure of amortisation periods for goodwill and intangible assets (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "172",
     "firstAnchor": {
      "contextRef": "c-5502",
      "name": "ifrs-full:UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5502",
      "name": "ifrs-full:UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R173": {
     "role": "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
     "longName": "9955623 - Disclosure - Goodwill and intangible assets - Disclosure of reconciliation of changes in intangible assets and goodwill (Details)",
     "shortName": "Goodwill and intangible assets - Disclosure of reconciliation of changes in intangible assets and goodwill (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "173",
     "firstAnchor": {
      "contextRef": "c-1105",
      "name": "ifrs-full:IntangibleAssetsAndGoodwill",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5466",
      "name": "ifrs-full:IntangibleAssetsAndGoodwill",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R174": {
     "role": "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofgoodwillallocatedtobusinessoperationsaccordingtobusinesssegmentsDetails",
     "longName": "9955624 - Disclosure - Goodwill and intangible assets - Disclosure of goodwill allocated to business operations according to business segments (Details)",
     "shortName": "Goodwill and intangible assets - Disclosure of goodwill allocated to business operations according to business segments (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "174",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:Goodwill",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5573",
      "name": "ifrs-full:Goodwill",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R175": {
     "role": "http://www.home.barclays/role/GoodwillandintangibleassetsNarrativeDetails",
     "longName": "9955625 - Disclosure - Goodwill and intangible assets - Narrative (Details)",
     "shortName": "Goodwill and intangible assets - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "175",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:ImpairmentReviewValueInUseForecastPeriod",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:ImpairmentReviewValueInUseForecastPeriod",
      "unitRef": null,
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": null,
      "ancestors": [
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R176": {
     "role": "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails",
     "longName": "9955626 - Disclosure - Goodwill and intangible assets - Disclosure of the outcome the impairment review (Details)",
     "shortName": "Goodwill and intangible assets - Disclosure of the outcome the impairment review (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "176",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:Goodwill",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5583",
      "name": "bbplc:TangibleEquity",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesExplanatory",
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R177": {
     "role": "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails",
     "longName": "9955627 - Disclosure - Goodwill and intangible assets - Disclosure of sensitivity of the value in use to key judgements in the calculations (Details)",
     "shortName": "Goodwill and intangible assets - Disclosure of sensitivity of the value in use to key judgements in the calculations (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "177",
     "firstAnchor": {
      "contextRef": "c-5585",
      "name": "bbplc:IntangibleAssetsAndGoodwillSensitiveToChangesInKeyVariables",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5585",
      "name": "bbplc:IntangibleAssetsAndGoodwillSensitiveToChangesInKeyVariables",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R178": {
     "role": "http://www.home.barclays/role/OtherliabilitiesDetails",
     "longName": "9955628 - Disclosure - Other liabilities (Details)",
     "shortName": "Other liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "178",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:AccrualsAndDeferredIncomeIncludingContractLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfOtherLiabilitiesExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:AccrualsAndDeferredIncomeIncludingContractLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfOtherLiabilitiesExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R179": {
     "role": "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails",
     "longName": "9955629 - Disclosure - Provisions - Disclosure of movements in provisions (Details)",
     "shortName": "Provisions - Disclosure of movements in provisions (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "179",
     "firstAnchor": {
      "contextRef": "c-1105",
      "name": "ifrs-full:Provisions",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfOtherProvisionsExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5598",
      "name": "ifrs-full:Provisions",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfOtherProvisionsExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R180": {
     "role": "http://www.home.barclays/role/ProvisionsNarrativeDetails",
     "longName": "9955630 - Disclosure - Provisions - Narrative (Details)",
     "shortName": "Provisions - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "180",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:Provisions",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfOtherProvisionsExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5488",
      "name": "ifrs-full:ExpectedReimbursementOtherProvisions",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R181": {
     "role": "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails",
     "longName": "9955631 - Disclosure - Contingent liabilities and commitments - Summary of contingent liabilities and commitments (Details)",
     "shortName": "Contingent liabilities and commitments - Summary of contingent liabilities and commitments (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "181",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:NotionalAmount",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfSummaryOfDerivativeAssetsAndLiabilitiesTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5620",
      "name": "ifrs-full:NotionalAmount",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R182": {
     "role": "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsNarrativeDetails",
     "longName": "9955632 - Disclosure - Contingent liabilities and commitments - Narrative (Details)",
     "shortName": "Contingent liabilities and commitments - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "182",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:Provisions",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfOtherProvisionsExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": null
    },
    "R183": {
     "role": "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails",
     "longName": "9955633 - Disclosure - Legal, competition and regulatory matters (Details)",
     "shortName": "Legal, competition and regulatory matters (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "183",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:Provisions",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfOtherProvisionsExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5641",
      "name": "bbplc:NumberOfFinalDecisionsByTheUKFinancialOmbudsmanService",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "INF",
      "ancestors": [
       "span",
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R184": {
     "role": "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofsubordinatedliabilitiesDetails",
     "longName": "9955634 - Disclosure - Subordinated liabilities - Disclosure of subordinated liabilities (Details)",
     "shortName": "Subordinated liabilities - Disclosure of subordinated liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "184",
     "firstAnchor": {
      "contextRef": "c-1105",
      "name": "ifrs-full:SubordinatedLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfDetailedInformationAboutBorrowingsExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:RepaymentsOfBorrowingsClassifiedAsFinancingActivities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfDetailedInformationAboutBorrowingsExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R185": {
     "role": "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails",
     "longName": "9955635 - Disclosure - Subordinated liabilities - Narrative (Details)",
     "shortName": "Subordinated liabilities - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "185",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ProceedsFromIssueOfSubordinatedLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfDetailedInformationAboutBorrowingsExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5647",
      "name": "ifrs-full:ProceedsFromIssueOfSubordinatedLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R186": {
     "role": "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedanddatedsubordinatedliabilitiesDetails",
     "longName": "9955636 - Disclosure - Subordinated liabilities - Disclosure of undated and dated subordinated liabilities (Details)",
     "shortName": "Subordinated liabilities - Disclosure of undated and dated subordinated liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "186",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:UndatedSubordinatedLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": null
    },
    "R187": {
     "role": "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails",
     "longName": "9955637 - Disclosure - Subordinated liabilities - Disclosure of undated subordinated liabilities (Details)",
     "shortName": "Subordinated liabilities - Disclosure of undated subordinated liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "187",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:NotionalAmount",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfSummaryOfDerivativeAssetsAndLiabilitiesTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5653",
      "name": "ifrs-full:UndatedSubordinatedLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R188": {
     "role": "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
     "longName": "9955638 - Disclosure - Subordinated liabilities - Disclosure of dated subordinated liabilities (Details)",
     "shortName": "Subordinated liabilities - Disclosure of dated subordinated liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "188",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:NotionalAmount",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfSummaryOfDerivativeAssetsAndLiabilitiesTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5660",
      "name": "ifrs-full:DatedSubordinatedLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R189": {
     "role": "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails",
     "longName": "9955639 - Disclosure - Ordinary shares, preference shares and other equity - Disclosure of called up share capital, allotted and fully paid (Details)",
     "shortName": "Ordinary shares, preference shares and other equity - Disclosure of called up share capital, allotted and fully paid (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "189",
     "firstAnchor": {
      "contextRef": "c-1105",
      "name": "ifrs-full:Equity",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-4799",
      "name": "ifrs-full:ReductionOfIssuedCapital",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfClassesOfShareCapitalExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R190": {
     "role": "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
     "longName": "9955640 - Disclosure - Ordinary shares, preference shares and other equity - Narrative (Details)",
     "shortName": "Ordinary shares, preference shares and other equity - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "190",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ProceedsFromIssuingShares",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5739",
      "name": "ifrs-full:NumberOfSharesIssuedAndFullyPaid",
      "unitRef": "shares",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "INF",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R191": {
     "role": "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
     "longName": "9955641 - Disclosure - Ordinary shares, preference shares and other equity - Disclosure of AT1 equity instruments (Details)",
     "shortName": "Ordinary shares, preference shares and other equity - Disclosure of AT1 equity instruments (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "191",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:NotionalAmount",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfSummaryOfDerivativeAssetsAndLiabilitiesTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5786",
      "name": "ifrs-full:OtherEquityInterest",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfShareCapitalReservesAndOtherEquityInterestExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R192": {
     "role": "http://www.home.barclays/role/ReservesDetails",
     "longName": "9955642 - Disclosure - Reserves (Details)",
     "shortName": "Reserves (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "192",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:OtherReserves",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfReservesWithinEquityTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5788",
      "name": "ifrs-full:OtherReserves",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfReservesWithinEquityTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R193": {
     "role": "http://www.home.barclays/role/StaffcostsDetails",
     "longName": "9955643 - Disclosure - Staff costs (Details)",
     "shortName": "Staff costs (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "193",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:OtherLongtermBenefits",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:ScheduleOfShortTermEmployeeBenefitsExplanatoryTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:OtherLongtermBenefits",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:ScheduleOfShortTermEmployeeBenefitsExplanatoryTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R194": {
     "role": "http://www.home.barclays/role/SharebasedpaymentsDisclosureofsharebasedpaymentschemesDetails",
     "longName": "9955644 - Disclosure - Share-based payments - Disclosure of share-based payment schemes (Details)",
     "shortName": "Share-based payments - Disclosure of share-based payment schemes (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "194",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ExpenseFromEquitysettledSharebasedPaymentTransactionsInWhichGoodsOrServicesReceivedDidNotQualifyForRecognitionAsAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:ExpenseFromEquitysettledSharebasedPaymentTransactionsInWhichGoodsOrServicesReceivedDidNotQualifyForRecognitionAsAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R195": {
     "role": "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails",
     "longName": "9955645 - Disclosure - Share-based payments - Disclosure of share option and award plans (Details)",
     "shortName": "Share-based payments - Disclosure of share option and award plans (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "195",
     "firstAnchor": {
      "contextRef": "c-5818",
      "name": "ifrs-full:WeightedAverageFairValueAtMeasurementDateShareOptionsGranted",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "2",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5818",
      "name": "ifrs-full:WeightedAverageFairValueAtMeasurementDateShareOptionsGranted",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "2",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R196": {
     "role": "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails",
     "longName": "9955646 - Disclosure - Share-based payments - Narrative (Details)",
     "shortName": "Share-based payments - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "196",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:LiabilitiesFromSharebasedPaymentTransactions2011",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:LiabilitiesFromSharebasedPaymentTransactions2011",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R197": {
     "role": "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails",
     "longName": "9955647 - Disclosure - Share-based payments - Disclosure of movements in options and awards (Details)",
     "shortName": "Share-based payments - Disclosure of movements in options and awards (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "197",
     "firstAnchor": {
      "contextRef": "c-5819",
      "name": "ifrs-full:NumberOfOutstandingShareOptions",
      "unitRef": "shares",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-3",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5807",
      "name": "bbplc:NumberOfShareOptionsTransferredInShareBasedPaymentArrangementShares",
      "unitRef": "shares",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-3",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R198": {
     "role": "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
     "longName": "9955648 - Disclosure - Retirement benefits - Narrative (Details)",
     "shortName": "Retirement benefits - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "198",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:CurrentServiceCostNetDefinedBenefitLiabilityAsset",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:NumberOfLongevityReinsuranceContracts",
      "unitRef": "contract",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "INF",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R199": {
     "role": "http://www.home.barclays/role/RetirementbenefitsDisclosureofincomestatementchargeDetails",
     "longName": "9955649 - Disclosure - Retirement benefits - Disclosure of income statement charge (Details)",
     "shortName": "Retirement benefits - Disclosure of income statement charge (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "199",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:CurrentServiceCostNetDefinedBenefitLiabilityAsset",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:IncreaseDecreaseThroughOtherChangesNetDefinedBenefitLiabilityAsset",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R200": {
     "role": "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
     "longName": "9955650 - Disclosure - Retirement benefits - Disclosure of balance sheet reconciliation (Details)",
     "shortName": "Retirement benefits - Disclosure of balance sheet reconciliation (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "200",
     "firstAnchor": {
      "contextRef": "c-1105",
      "name": "ifrs-full:LiabilityAssetOfDefinedBenefitPlans",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfNetDefinedBenefitLiabilityAssetExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5841",
      "name": "ifrs-full:LiabilityAssetOfDefinedBenefitPlans",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfNetDefinedBenefitLiabilityAssetExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R201": {
     "role": "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
     "longName": "9955651 - Disclosure - Retirement benefits - Breakdown of the UKRF benefit obligation (Details)",
     "shortName": "Retirement benefits - Breakdown of the UKRF benefit obligation (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "201",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:LiabilityAssetOfDefinedBenefitPlans",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfNetDefinedBenefitLiabilityAssetExplanatory",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5879",
      "name": "ifrs-full:LiabilityAssetOfDefinedBenefitPlans",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R202": {
     "role": "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
     "longName": "9955652 - Disclosure - Retirement benefits - Disclosure of actuarial valuation of schemes (Details)",
     "shortName": "Retirement benefits - Disclosure of actuarial valuation of schemes (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "202",
     "firstAnchor": {
      "contextRef": "c-5886",
      "name": "ifrs-full:ActuarialAssumptionOfDiscountRates",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "4",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-5886",
      "name": "ifrs-full:ActuarialAssumptionOfDiscountRates",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "4",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R203": {
     "role": "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
     "longName": "9955653 - Disclosure - Retirement benefits - Disclosure of analysis of scheme assets (Details)",
     "shortName": "Retirement benefits - Disclosure of analysis of scheme assets (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "203",
     "firstAnchor": {
      "contextRef": "c-952",
      "name": "bbplc:TransfersOutOfLevel2Or3IntoLevel1FairValueHierarchyAssetsHeldAtEndOfReportingPeriod",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "bbplc:TransfersOutOfLevel1IntoLevel2Or3FairValueHierarchyAssetsHeldAtEndOfReportingPeriod",
       "span",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-952",
      "name": "bbplc:TransfersOutOfLevel2Or3IntoLevel1FairValueHierarchyAssetsHeldAtEndOfReportingPeriod",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "bbplc:TransfersOutOfLevel1IntoLevel2Or3FairValueHierarchyAssetsHeldAtEndOfReportingPeriod",
       "span",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R204": {
     "role": "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
     "longName": "9955654 - Disclosure - Principal subsidiaries - Narrative (Details)",
     "shortName": "Principal subsidiaries - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "204",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:InvestmentsInSubsidiariesReportedInSeparateFinancialStatementsIncreaseDecrease",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:InvestmentsInSubsidiariesReportedInSeparateFinancialStatementsIncreaseDecrease",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R205": {
     "role": "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails",
     "longName": "9955655 - Disclosure - Principal subsidiaries - Disclosure of principal subsidiaries (Details)",
     "shortName": "Principal subsidiaries - Disclosure of principal subsidiaries (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "205",
     "firstAnchor": {
      "contextRef": "c-6093",
      "name": "ifrs-full:ProportionOfVotingPowerHeldInSubsidiary",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "2",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6093",
      "name": "ifrs-full:ProportionOfVotingPowerHeldInSubsidiary",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "2",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R206": {
     "role": "http://www.home.barclays/role/StructuredentitiesNarrativeDetails",
     "longName": "9955656 - Disclosure - Structured entities - Narrative (Details)",
     "shortName": "Structured entities - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "206",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "bbplc:NumberOfStructuredEntities",
      "unitRef": "entity",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-3",
      "ancestors": [
       "span",
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "bbplc:NumberOfStructuredEntities",
      "unitRef": "entity",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-3",
      "ancestors": [
       "span",
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R207": {
     "role": "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails",
     "longName": "9955657 - Disclosure - Structured entities - Summary of interests in unconsolidated structured entities (Details)",
     "shortName": "Structured entities - Summary of interests in unconsolidated structured entities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "207",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6110",
      "name": "ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R208": {
     "role": "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails",
     "longName": "9955658 - Disclosure - Structured entities - Nature of interest (Details)",
     "shortName": "Structured entities - Nature of interest (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "208",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssetsAtFairValueThroughProfitOrLoss",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6109",
      "name": "bbplc:OffBalanceSheetNotionalAmountsOfAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R209": {
     "role": "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresDisclosureofinvestmentsinassociatesandjointventuresDetails",
     "longName": "9955659 - Disclosure - Investments in associates and joint ventures - Disclosure of investments in associates and joint ventures (Details)",
     "shortName": "Investments in associates and joint ventures - Disclosure of investments in associates and joint ventures (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "209",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:InvestmentsInAssociatesAccountedForUsingEquityMethod",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DetailedInformationAboutInvestmentsInAssociatesAndJointVenturesTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:InvestmentsInAssociatesAccountedForUsingEquityMethod",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DetailedInformationAboutInvestmentsInAssociatesAndJointVenturesTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R210": {
     "role": "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails",
     "longName": "9955660 - Disclosure - Investments in associates and joint ventures - Summarised financial information, equity accounted associates and joint ventures (Details)",
     "shortName": "Investments in associates and joint ventures - Summarised financial information, equity accounted associates and joint ventures (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "210",
     "firstAnchor": {
      "contextRef": "c-6130",
      "name": "ifrs-full:ShareOfProfitLossOfContinuingOperationsOfAssociatesAndJointVenturesAccountedForUsingEquityMethod",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6130",
      "name": "ifrs-full:ShareOfProfitLossOfContinuingOperationsOfAssociatesAndJointVenturesAccountedForUsingEquityMethod",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R211": {
     "role": "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails",
     "longName": "9955661 - Disclosure - Securitisations - Disclosure of transfers of financial assets that do not result in derecognition (Details)",
     "shortName": "Securitisations - Disclosure of transfers of financial assets that do not result in derecognition (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "211",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:AssetsThatEntityContinuesToRecognise",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6133",
      "name": "ifrs-full:AssetsThatEntityContinuesToRecognise",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R212": {
     "role": "http://www.home.barclays/role/SecuritisationsNarrativeDetails",
     "longName": "9955662 - Disclosure - Securitisations - Narrative (Details)",
     "shortName": "Securitisations - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "212",
     "firstAnchor": {
      "contextRef": "c-6139",
      "name": "ifrs-full:AssetsThatEntityContinuesToRecogniseToExtentOfContinuingInvolvement",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6139",
      "name": "ifrs-full:AssetsThatEntityContinuesToRecogniseToExtentOfContinuingInvolvement",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R213": {
     "role": "http://www.home.barclays/role/SecuritisationsDisclosureofcontinuinginvolvementinfinancialassetsthathavebeenderecognisedDetails",
     "longName": "9955663 - Disclosure - Securitisations - Disclosure of continuing involvement in financial assets that have been derecognised (Details)",
     "shortName": "Securitisations - Disclosure of continuing involvement in financial assets that have been derecognised (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "213",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:RecognisedAssetsRepresentingContinuingInvolvementInDerecognisedFinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:RecognisedAssetsRepresentingContinuingInvolvementInDerecognisedFinancialAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R214": {
     "role": "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcarryingamountoftheassetspledgedassecurityagainstliabilitiesDetails",
     "longName": "9955664 - Disclosure - Assets pledged, collateral received and assets transferred - Disclosure of carrying amount of the assets pledged as security against liabilities (Details)",
     "shortName": "Assets pledged, collateral received and assets transferred - Disclosure of carrying amount of the assets pledged as security against liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "214",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssetsPledgedAsCollateralForLiabilitiesOrContingentLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:FinancialAssetsPledgedAsCollateralForLiabilitiesOrContingentLiabilities",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R215": {
     "role": "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureoftransferredfinancialassetsandtheassociatedliabilitiesDetails",
     "longName": "9955665 - Disclosure - Assets pledged, collateral received and assets transferred - Disclosure of transferred financial assets and the associated liabilities (Details)",
     "shortName": "Assets pledged, collateral received and assets transferred - Disclosure of transferred financial assets and the associated liabilities (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "215",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:AssetsThatEntityContinuesToRecognise",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6159",
      "name": "ifrs-full:AssetsThatEntityContinuesToRecognise",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R216": {
     "role": "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails",
     "longName": "9955666 - Disclosure - Assets pledged, collateral received and assets transferred - Disclosure of recourse to transferred assets (Details)",
     "shortName": "Assets pledged, collateral received and assets transferred - Disclosure of recourse to transferred assets (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "216",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:AssetsThatEntityContinuesToRecognise",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6167",
      "name": "ifrs-full:AssetsThatEntityContinuesToRecognise",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R217": {
     "role": "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredNarrativeDetails",
     "longName": "9955667 - Disclosure - Assets pledged, collateral received and assets transferred - Narrative (Details)",
     "shortName": "Assets pledged, collateral received and assets transferred - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "217",
     "firstAnchor": {
      "contextRef": "c-6169",
      "name": "ifrs-full:LoansAndAdvances",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6169",
      "name": "ifrs-full:LoansAndAdvances",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R218": {
     "role": "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcollateralheldassecurityforassetsDetails",
     "longName": "9955668 - Disclosure - Assets pledged, collateral received and assets transferred - Disclosure of collateral held as security for assets (Details)",
     "shortName": "Assets pledged, collateral received and assets transferred - Disclosure of collateral held as security for assets (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "218",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:AssetsHeldAsCollateralPermittedToBeSoldOrRepledgedAtFairValue",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:AssetsHeldAsCollateralPermittedToBeSoldOrRepledgedAtFairValue",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R219": {
     "role": "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofamountsincludedintheGroupsfinancialstatementsbycategoryDetails",
     "longName": "9955669 - Disclosure - Related party transactions and Directors' remuneration - Disclosure of amounts included in the Group's financial statements by category (Details)",
     "shortName": "Related party transactions and Directors' remuneration - Disclosure of amounts included in the Group's financial statements by category (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "219",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "bbplc:OperatingIncome",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6171",
      "name": "bbplc:OperatingIncome",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R220": {
     "role": "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails",
     "longName": "9955670 - Disclosure - Related party transactions and Directors' remuneration - Narrative (Details)",
     "shortName": "Related party transactions and Directors' remuneration - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "220",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:PostemploymentBenefitExpenseDefinedBenefitPlans",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:ScheduleOfShortTermEmployeeBenefitsExplanatoryTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6173",
      "name": "bbplc:DerivativeTransactionsDuringPeriodRelatedPartyTransactions",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R221": {
     "role": "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofloansanddepositsoutstandingDetails",
     "longName": "9955671 - Disclosure - Related party transactions and Directors' remuneration - Disclosure of loans and deposits outstanding (Details)",
     "shortName": "Related party transactions and Directors' remuneration - Disclosure of loans and deposits outstanding (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "221",
     "firstAnchor": {
      "contextRef": "c-6191",
      "name": "ifrs-full:AmountsReceivableRelatedPartyTransactions",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-5",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6191",
      "name": "ifrs-full:AmountsReceivableRelatedPartyTransactions",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-5",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R222": {
     "role": "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails",
     "longName": "9955672 - Disclosure - Related party transactions and Directors' remuneration - Disclosure of remuneration of Directors and other Key Management Personnel (Details)",
     "shortName": "Related party transactions and Directors' remuneration - Disclosure of remuneration of Directors and other Key Management Personnel (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "222",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:KeyManagementPersonnelCompensationShorttermEmployeeBenefits",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-5",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesExplanatory",
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:KeyManagementPersonnelCompensationShorttermEmployeeBenefits",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-5",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ifrs-full:DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesExplanatory",
       "div",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R223": {
     "role": "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details",
     "longName": "9955673 - Disclosure - Related party transactions and Directors' remuneration - Disclosure required by the Companies Act 2006 (Details)",
     "shortName": "Related party transactions and Directors' remuneration - Disclosure required by the Companies Act 2006 (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "223",
     "firstAnchor": {
      "contextRef": "c-6193",
      "name": "bbplc:AggregateEmolumentsCompaniesAct2006",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-5",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6193",
      "name": "bbplc:AggregateEmolumentsCompaniesAct2006",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-5",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "div",
       "ix:continuation",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R224": {
     "role": "http://www.home.barclays/role/AcquisitionandDisposalsofsubsidiariesDetails",
     "longName": "9955674 - Disclosure - Acquisition and Disposals of subsidiaries (Details)",
     "shortName": "Acquisition and Disposals of subsidiaries (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "224",
     "firstAnchor": {
      "contextRef": "c-6214",
      "name": "ifrs-full:ConsiderationPaidReceived",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6214",
      "name": "ifrs-full:ConsiderationPaidReceived",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    },
    "R225": {
     "role": "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails",
     "longName": "9955675 - Disclosure - Auditor's remuneration - Disclosure of Auditor's remuneration (Details)",
     "shortName": "Auditor's remuneration - Disclosure of Auditor's remuneration (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "225",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:AuditorsRemunerationForAuditServices",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:AuditorsRemuneration",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R226": {
     "role": "http://www.home.barclays/role/AuditorsremunerationNarrativeDetails",
     "longName": "9955676 - Disclosure - Auditor's remuneration - Narrative (Details)",
     "shortName": "Auditor's remuneration - Narrative (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "226",
     "firstAnchor": {
      "contextRef": "c-1",
      "name": "ifrs-full:AuditorsRemunerationForAuditServices",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6227",
      "name": "ifrs-full:AuditorsRemunerationForAuditServices",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R227": {
     "role": "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails",
     "longName": "9955677 - Disclosure - Assets and liabilities included in disposal group classified as held for sale (Details)",
     "shortName": "Assets and liabilities included in disposal group classified as held for sale (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "227",
     "firstAnchor": {
      "contextRef": "c-8",
      "name": "ifrs-full:OtherAssets",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true
     },
     "uniqueAnchor": {
      "contextRef": "c-8",
      "name": "bbplc:NetAssetsLiabilitiesOrDisposalGroupsClassifiedAsHeldForSale",
      "unitRef": "gbp",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "-6",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "ix:continuation",
       "ix:continuation",
       "div",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "unique": true
     }
    },
    "R228": {
     "role": "http://www.home.barclays/role/RelatedUndertakingsDetails",
     "longName": "9955678 - Disclosure - Related Undertakings (Details)",
     "shortName": "Related Undertakings (Details)",
     "isDefault": "false",
     "groupType": "disclosure",
     "subGroupType": "details",
     "menuCat": "Details",
     "order": "228",
     "firstAnchor": {
      "contextRef": "c-6238",
      "name": "bbplc:ProportionOfOwnershipInterestHeldInSignificantInvestments",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "4",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfInterestsInOtherRelatedUndertakingsTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     },
     "uniqueAnchor": {
      "contextRef": "c-6238",
      "name": "bbplc:ProportionOfOwnershipInterestHeldInSignificantInvestments",
      "unitRef": "number",
      "xsiNil": "false",
      "lang": "en-US",
      "decimals": "4",
      "ancestors": [
       "span",
       "div",
       "div",
       "div",
       "td",
       "tr",
       "tbody",
       "table",
       "div",
       "div",
       "bbplc:DisclosureOfInterestsInOtherRelatedUndertakingsTableTextBlock",
       "div",
       "ix:continuation",
       "div",
       "div",
       "body",
       "html"
      ],
      "reportCount": 1,
      "baseRef": "bbplc-20251231.htm",
      "first": true,
      "unique": true
     }
    }
   },
   "tag": {
    "bbplc_A1125FixedRateResettingSubordinatedCallableNotesDue2031Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A1125FixedRateResettingSubordinatedCallableNotesDue2031Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "1.125% Fixed Rate Resetting Subordinated Callable Notes (EUR 1,000m)",
        "label": "1.125% Fixed Rate Resetting Subordinated Callable Notes, Due 2031 [Member]",
        "documentation": "1.125% Fixed Rate Resetting Subordinated Callable Notes, Due 2031"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A3.750FixedRateResettingSubordinatedCallableNotesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A3.750FixedRateResettingSubordinatedCallableNotesMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "3.750% Fixed Rate Resetting Subordinated Callable Notes",
        "label": "3.750% Fixed Rate Resetting Subordinated Callable Notes [Member]",
        "documentation": "3.750% Fixed Rate Resetting Subordinated Callable Notes"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A375ResettingSubordinatedCallableNotesDue2030Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A375ResettingSubordinatedCallableNotesDue2030Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "3.75% Fixed Rate Resetting Subordinated Callable Notes (SGD 200m)",
        "label": "3.75% Resetting Subordinated Callable Notes, Due 2030 [Member]",
        "documentation": "This member stands for the resetting Subordinated Notes, maturing in 2030 and denominated in Singapore, Dollars currency."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A3811FixedRateResettingSubordinatedCallableNotesDue2042Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A3811FixedRateResettingSubordinatedCallableNotesDue2042Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "3.811% Fixed Rate Resetting Subordinated Callable Notes (USD 1,000m)",
        "label": "3.811% Fixed Rate Resetting Subordinated Callable Notes, Due 2042 [Member]",
        "documentation": "3.811% Fixed Rate Resetting Subordinated Callable Notes, Due 2042"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A3MonthEuroInterbankOfferedRateMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A3MonthEuroInterbankOfferedRateMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "3-Month Euribor",
        "label": "3-Month Euro Interbank Offered Rate [Member]",
        "documentation": "3-Month Euro Interbank Offered Rate"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A3MonthLondonInterbankOfferedRateMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A3MonthLondonInterbankOfferedRateMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "3-Month LIBOR",
        "label": "3-Month London Interbank Offered Rate [Member]",
        "documentation": "3-Month London Interbank Offered Rate"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A4.616FixedRateResettingSubordinatedCallableNotesDue2037Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A4.616FixedRateResettingSubordinatedCallableNotesDue2037Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "4.616% Fixed Rate Resetting Subordinated Callable Notes (EUR 800m)",
        "label": "4.616% Fixed Rate Resetting Subordinated Callable Notes, Due 2037 [Member]",
        "documentation": "4.616% Fixed Rate Resetting Subordinated Callable Notes, Due 2037"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A4.650PerpetualSubordinatedContingentConvertibleSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A4.650PerpetualSubordinatedContingentConvertibleSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "4.650% Perpetual Subordinated Contingent Convertible Securities (SGD500m)",
        "label": "4.650% Perpetual Subordinated Contingent Convertible Securities [Member]",
        "documentation": "4.650% Perpetual Subordinated Contingent Convertible Securities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A4.75Euro100ParValueMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A4.75Euro100ParValueMember",
     "presentation": [
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Euro preference shares",
        "verboseLabel": "4.75% Euro preference shares",
        "label": "4.75% Euro 100 Par Value [Member]",
        "documentation": "This member stands for the 4.75% EURO 100 par value non-cumulative callable preference shares."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A4.836FixedRateSubordinatedNotesDue2028Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A4.836FixedRateSubordinatedNotesDue2028Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "4.836% Fixed Rate Subordinated Notes (USD 1,200m)",
        "label": "4.836% Fixed Rate Subordinated Notes, Due 2028 [Member]",
        "documentation": "This member stands for the Subordinated Notes, maturing in 2028 and denominated in United States of America, Dollars currency."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A4.973FixedRateResettingSubordinatedCallableNotesDue2036Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A4.973FixedRateResettingSubordinatedCallableNotesDue2036Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "4.973% Fixed Rate Resetting Subordinated Callable Notes (EUR 1,500m)",
        "label": "4.973% Fixed Rate Resetting Subordinated Callable Notes, Due 2036 [Member]",
        "documentation": "4.973% Fixed Rate Resetting Subordinated Callable Notes, Due 2036"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A4375PerpetualSubordinatedContingentConvertibleSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A4375PerpetualSubordinatedContingentConvertibleSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "4.375% Perpetual Subordinated Contingent Convertible Securities (USD1,500m)",
        "label": "4.375% Perpetual Subordinated Contingent Convertible Securities [Member]",
        "documentation": "4.375% Perpetual Subordinated Contingent Convertible Securities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A495FixedRateSubordinatedNotesDue2047Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A495FixedRateSubordinatedNotesDue2047Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "4.95% Fixed Rate Subordinated Notes (USD 1,250m)",
        "label": "4.95% Fixed Rate Subordinated Notes, Due 2047 [Member]",
        "documentation": "This member stands for the 4.95% Subordinated Notes, maturing in 2047 and denominated in United States of America, Dollars currency."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A5.400PerpetualSubordinatedContingentConvertibleSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A5.400PerpetualSubordinatedContingentConvertibleSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "5.400% Perpetual Subordinated Contingent Convertible Securities (SGD600m)",
        "label": "5.400% Perpetual Subordinated Contingent Convertible Securities [Member]",
        "documentation": "5.400% Perpetual Subordinated Contingent Convertible Securities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A503ReverseDualCurrencyUndatedSubordinatedLoanMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A503ReverseDualCurrencyUndatedSubordinatedLoanMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "5.03% Reverse Dual Currency Undated Subordinated Loan (JPY\u00a08,000m)",
        "label": "5.03% Reverse Dual Currency Undated Subordinated Loan [Member]",
        "documentation": "This member stands for the 5.03% Reverse Dual Currency Undated Subordinated Loan, with an initial call date of 2028 and denominated in Japan, Yen currency."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A5088FixedToFloatingRateSubordinatedCallableNotesDue2030Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A5088FixedToFloatingRateSubordinatedCallableNotesDue2030Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "5.088% Fixed-to-Floating Rate Subordinated Callable Notes (USD 1,300m)",
        "label": "5.088% Fixed-To-Floating Rate Subordinated Callable Notes, Due 2030 [Member]",
        "documentation": "This member stands for the 5.088% Callable Tier 2 Subordinated Notes."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A520FixedRateSubordinatedNotesDue2026Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A520FixedRateSubordinatedNotesDue2026Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "5.20% Fixed Rate Subordinated Notes (USD 1,367m)",
        "label": "5.20% Fixed Rate Subordinated Notes, Due 2026 [Member]",
        "documentation": "This member stands for the Subordinated Notes, maturing in 2026 and denominated in United States of America, Dollars currency."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A525FixedRateSubordinatedNotesDue2045Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A525FixedRateSubordinatedNotesDue2045Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "5.25% Fixed Rate Subordinated Notes (USD 827m)",
        "label": "5.25% Fixed Rate Subordinated Notes, Due 2045 [Member]",
        "documentation": "This member stands for the 5.25% Subordinated Notes, maturing in 2045 and denominated in United States of America, Dollars currency."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A5262FixedRateResettingSeniorCallableNotesDue2034Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A5262FixedRateResettingSeniorCallableNotesDue2034Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "5.262% Fixed Rate Resetting Subordinated Callable Notes (EUR 1,250m)",
        "label": "5.262% Fixed Rate Resetting Senior Callable Notes, Due 2034 [Member]",
        "documentation": "5.262% Fixed Rate Resetting Senior Callable Notes, Due 2034"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A54ReverseDualCurrencySubordinatedLoanDue2027Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A54ReverseDualCurrencySubordinatedLoanDue2027Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "5.4% Reverse Dual Currency Subordinated Loan (JPY 15,000m)",
        "label": "5.4% Reverse Dual Currency Subordinated Loan, Due 2027 [Member]",
        "documentation": "This member stands for the 5.4% Reverse Dual Currency Subordinated Loan (JPY 15,000m) maturing in 2027, denominated in Japan, Yen currency."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A575FixedRateSubordinatedNotesDue2026Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A575FixedRateSubordinatedNotesDue2026Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "5.75% Fixed Rate Subordinated Notes",
        "label": "5.75% Fixed Rate Subordinated Notes, Due 2026 [Member]",
        "documentation": "This member stands for the 5.75% Fixed Rate Subordinated Notes maturing in 2026."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A5ReverseDualCurrencySubordinatedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A5ReverseDualCurrencySubordinatedMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "5% Reverse Dual Currency Undated Subordinated Loan (JPY\u00a012,000m)",
        "label": "5% Reverse Dual Currency Subordinated [Member]",
        "documentation": "This member stands for the 5% Reverse Dual Currency Undated Subordinated Loan, with an initial call date of 2028 and denominated in Japan, Yen currency."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A6.125PerpetualSubordinatedContingentConvertibleSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A6.125PerpetualSubordinatedContingentConvertibleSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "6.125% Perpetual Subordinated Contingent Convertible Securities (EUR1,500m)",
        "label": "6.125% Perpetual Subordinated Contingent Convertible Securities [Member]",
        "documentation": "6.125% Perpetual Subordinated Contingent Convertible Securities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A6125PerpetualSubordinatedContingentConvertibleSecuritiesDue2025Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A6125PerpetualSubordinatedContingentConvertibleSecuritiesDue2025Member",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "6.125% Perpetual Subordinated Contingent Convertible Securities (USD1,500m)",
        "label": "6.125% Perpetual Subordinated Contingent Convertible Securities Due 2025 [Member]",
        "documentation": "This member stands for the 6.125% USD denominated currency, Fixed Rate Resetting Perpetual Subordinated Contingent Convertible Securities of the entity, with an initial call date of 2025."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A6125UndatedSubordinatedNotesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A6125UndatedSubordinatedNotesMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "6.125% Undated Subordinated Notes",
        "label": "6.125% Undated Subordinated Notes [Member]",
        "documentation": "This member stands for the 6.125% Undated Subordinated Notes, with an initial call date of 2027."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A6278USD100ParValueMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A6278USD100ParValueMember",
     "presentation": [
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "US Dollar preference shares",
        "terseLabel": "6.278% US preference shares",
        "label": "6.278% USD 100 Par Value [Member]",
        "documentation": "This member stands for the 6.278% US$100 par value non-cumulative callable preference shares."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A633SubordinatedNotesDue2032Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A633SubordinatedNotesDue2032Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "6.33% Subordinated Notes (GBP 50m)",
        "label": "6.33% Subordinated Notes, Due 2032 [Member]",
        "documentation": "This member stands for the 6.33% Subordinated Notes maturing in 2032."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A6375PerpetualSubordinatedContingentConvertibleSecuritiesDue2025Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A6375PerpetualSubordinatedContingentConvertibleSecuritiesDue2025Member",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "6.375% Perpetual Subordinated Contingent Convertible Securities",
        "label": "6.375% Perpetual Subordinated Contingent Convertible Securities Due 2025 [Member]",
        "documentation": "This member stands for the 6.375% GBP denominated currency, Fixed Rate Resetting Perpetual Subordinated Contingent Convertible Securities of the entity, with an initial call date of 2025."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A7.625PerpetualSubordinatedContingentConvertibleSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A7.625PerpetualSubordinatedContingentConvertibleSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "7.625% Perpetual Subordinated Contingent Convertible Securities (USD1,500m)",
        "label": "7.625% Perpetual Subordinated Contingent Convertible Securities [Member]",
        "documentation": "7.625% Perpetual Subordinated Contingent Convertible Securities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A7119FixedToFloatingRateSubordinatedCallableNotesDue2034Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A7119FixedToFloatingRateSubordinatedCallableNotesDue2034Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "7.119% Fixed-to-Floating Rate Subordinated Callable Notes (USD 860m)",
        "label": "7.119% Fixed-To-Floating Rate Subordinated Callable Notes Due 2034 [Member]",
        "documentation": "7.119% Fixed-To-Floating Rate Subordinated Callable Notes Due 2034"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A7125PerpetualSubordinatedContingentConvertibleSecuritiesDue2025Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A7125PerpetualSubordinatedContingentConvertibleSecuritiesDue2025Member",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "7.125% Perpetual Subordinated Contingent Convertible Securities",
        "label": "7.125% Perpetual Subordinated Contingent Convertible Securities Due 2025 [Member]",
        "documentation": "This member stands for the 7.125% GBP denominated currency, Fixed Rate Resetting Perpetual Subordinated Contingent Convertible Securities of the entity, with an initial call date of 2025"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A7300PerpetualSubordinatedContingentConvertibleSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A7300PerpetualSubordinatedContingentConvertibleSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "7.300% Perpetual Subordinated Contingent Convertible Securities (SGD400m)",
        "label": "7.300% Perpetual Subordinated Contingent Convertible Securities [Member]",
        "documentation": "7.300% Perpetual Subordinated Contingent Convertible Securities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A7437FixedRateResettingSeniorCallableNotesDue2033Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A7437FixedRateResettingSeniorCallableNotesDue2033Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "7.437% Fixed Rate Resetting Subordinated Callable Notes (USD 2,000m)",
        "label": "7.437% Fixed Rate Resetting Senior Callable Notes, Due 2033 [Member]",
        "documentation": "7.437% Fixed Rate Resetting Senior Callable Notes, Due 2033"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A8.407FixedRateResettingSubordinatedCallableLoanDue2032Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A8.407FixedRateResettingSubordinatedCallableLoanDue2032Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "8.407% Fixed Rate Resetting Subordinated Callable Loan (GBP 1,000m)",
        "label": "8.407% Fixed Rate Resetting Subordinated Callable Loan, Due 2032 [Member]",
        "documentation": "8.407% Fixed Rate Resetting Subordinated Callable Loan, Due 2032"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A8.500PerpetualSubordinatedContingentConvertibleSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A8.500PerpetualSubordinatedContingentConvertibleSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "8.500% Perpetual Subordinated Contingent Convertible Securities",
        "label": "8.500% Perpetual Subordinated Contingent Convertible Securities [Member]",
        "documentation": "8.500% Perpetual Subordinated Contingent Convertible Securities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A8000PerpetualSubordinatedContingentConvertibleSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A8000PerpetualSubordinatedContingentConvertibleSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "8.000% Perpetual Subordinated Contingent Convertible Securities (USD2,000m)",
        "label": "8.000% Perpetual Subordinated Contingent Convertible Securities [Member]",
        "documentation": "8.000% Perpetual Subordinated Contingent Convertible Securities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A8300PerpetualSubordinatedContingentConvertibleSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A8300PerpetualSubordinatedContingentConvertibleSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "8.300% Perpetual Subordinated Contingent Convertible Securities (SGD450m)",
        "label": "8.300% Perpetual Subordinated Contingent Convertible Securities [Member]",
        "documentation": "8.300% Perpetual Subordinated Contingent Convertible Securities (SGD 450m)"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A8875PerpetualSubordinatedContingentConvertibleSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A8875PerpetualSubordinatedContingentConvertibleSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "8.875% Perpetual Subordinated Contingent Convertible Securities",
        "label": "8.875% Perpetual Subordinated Contingent Convertible Securities [Member]",
        "documentation": "8.875% Perpetual Subordinated Contingent Convertible Securities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A9250PerpetualSubordinatedContingentConvertibleSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A9250PerpetualSubordinatedContingentConvertibleSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "9.250% Perpetual Subordinated Contingent Convertible Securities",
        "label": "9.250% Perpetual Subordinated Contingent Convertible Securities [Member]",
        "documentation": "9.250% Perpetual Subordinated Contingent Convertible Securities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_A9625PerpetualSubordinatedContingentConvertibleSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "A9625PerpetualSubordinatedContingentConvertibleSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "9.625% Perpetual Subordinated Contingent Convertible Securities (USD1,750m)",
        "label": "9.625% Perpetual Subordinated Contingent Convertible Securities [Member]",
        "documentation": "9.625% Perpetual Subordinated Contingent Convertible Securities"
       }
      }
     },
     "auth_ref": []
    },
    "currency_AUD": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/currency/2025",
     "localname": "AUD",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AUD",
        "label": "Australia, Dollars"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AccrualsAndDeferredIncomeIncludingContractLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AccrualsAndDeferredIncomeIncludingContractLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/OtherliabilitiesDetails": {
       "parentTag": "ifrs-full_OtherLiabilities",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OtherliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accruals and deferred income",
        "label": "Accruals and deferred income including contract liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of accruals and deferred income, including contract liabilities. [Refer: Accruals; Deferred income including contract liabilities]"
       }
      }
     },
     "auth_ref": [
      "r883",
      "r885"
     ]
    },
    "ifrs-full_AccrualsAndDeferredIncomeIncludingContractLiabilitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AccrualsAndDeferredIncomeIncludingContractLiabilitiesAbstract",
     "lang": {
      "en-us": {
       "role": {
        "label": "Accruals and deferred income including contract liabilities [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AccumulatedChangesInFairValueOfFinancialAssetsAttributableToChangesInCreditRiskOfFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AccumulatedChangesInFairValueOfFinancialAssetsAttributableToChangesInCreditRiskOfFinancialAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cumulative changes in fair value from inception",
        "label": "Accumulated increase (decrease) in fair value of financial assets designated as measured at fair value through profit or loss, attributable to changes in credit risk of financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The accumulated increase (decrease) in the fair value of financial assets designated as measured at fair value through profit or loss that is attributable to changes in the credit risk of the assets determined either: (a) as the amount of change in their fair value that is not attributable to changes in market conditions that gave rise to market risk; or (b) using an alternative method that the entity believes more faithfully represents the amount of change in its fair value that is attributable to changes in the credit risk of the asset. [Refer: Credit risk [member]; Market risk [member]; Increase (decrease) in fair value of financial assets designated as measured at fair value through profit or loss, attributable to changes in credit risk of financial assets]"
       }
      }
     },
     "auth_ref": [
      "r321"
     ]
    },
    "ifrs-full_AccumulatedChangesInFairValueOfFinancialLiabilityAttributableToChangesInCreditRiskOfLiability": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AccumulatedChangesInFairValueOfFinancialLiabilityAttributableToChangesInCreditRiskOfLiability",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cumulative own credit net loss recognised",
        "label": "Accumulated increase (decrease) in fair value of financial liability, attributable to changes in credit risk of liability"
       }
      },
      "en": {
       "role": {
        "documentation": "The accumulated increase (decrease) in the fair value of financial liabilities that is attributable to changes in the credit risk of the liabilities. [Refer: Credit risk [member]; Market risk [member]; Increase (decrease) in fair value of financial liability, attributable to changes in credit risk of liability]"
       }
      }
     },
     "auth_ref": [
      "r236",
      "r237",
      "r482",
      "r483"
     ]
    },
    "ifrs-full_AccumulatedDepreciationAmortisationAndImpairmentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AccumulatedDepreciationAmortisationAndImpairmentMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accumulated depreciation and impairment",
        "verboseLabel": "Accumulated amortisation and impairment",
        "label": "Accumulated depreciation, amortisation and impairment [member]"
       }
      }
     },
     "auth_ref": [
      "r14",
      "r17",
      "r101",
      "r113",
      "r116",
      "r400",
      "r450",
      "r455",
      "r458"
     ]
    },
    "ifrs-full_AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails": {
       "parentTag": "bbplc_AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountNet",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accumulated fair value hedge adjustment included in carrying amount",
        "label": "Accumulated fair value hedge adjustment on hedged item included in carrying amount, assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The accumulated amount of fair value hedge adjustment on a hedged item that is included in the carrying amount of the hedged item, recognised in the statement of financial position as an asset. [Refer: Hedged items [domain]]"
       }
      }
     },
     "auth_ref": [
      "r261",
      "r496"
     ]
    },
    "bbplc_AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountAssetsLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountAssetsLiabilities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureoffairvalueadjustmentsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fair value adjustments",
        "label": "Accumulated Fair Value Hedge Adjustment On Hedged Item Included In Carrying Amount, Assets (Liabilities)",
        "documentation": "The accumulated amount of fair value hedge adjustment on a hedged item that is included in the carrying amount of the hedged item, recognised in the statement of financial position as an asset or liability."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails": {
       "parentTag": "bbplc_AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountNet",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Accumulated fair value hedge adjustment included in carrying amount",
        "label": "Accumulated fair value hedge adjustment on hedged item included in carrying amount, liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The accumulated amount of fair value hedge adjustment on a hedged item that is included in the carrying amount of the hedged item, recognised in the statement of financial position as a liability. [Refer: Hedged items [domain]]"
       }
      }
     },
     "auth_ref": [
      "r261",
      "r496"
     ]
    },
    "bbplc_AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountNet": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AccumulatedFairValueHedgeAdjustmentOnHedgedItemIncludedInCarryingAmountNet",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Accumulated fair value hedge adjustment included in carrying amount, total",
        "label": "Accumulated Fair Value Hedge Adjustment On Hedged Item Included In Carrying Amount, Net",
        "documentation": "The accumulated amount of fair value hedge adjustment on a hedged item that is included in the carrying amount of the hedged item, recognised in the statement of financial position as an asset less liabilities. [Refer: Hedged items [member]]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails": {
       "parentTag": "bbplc_AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesNet",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accumulated fair value adjustment on items no longer in a hedge relationship",
        "label": "Accumulated fair value hedge adjustment remaining in statement of financial position for hedged item that ceased to be adjusted for hedging gains and losses, assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The accumulated amount of fair value hedge adjustment remaining in the statement of financial position for a hedged item that is a financial asset measured at amortised cost and has ceased to be adjusted for hedging gains and losses. [Refer: Financial assets at amortised cost; Hedged items [domain]]"
       }
      }
     },
     "auth_ref": [
      "r263"
     ]
    },
    "ifrs-full_AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails": {
       "parentTag": "bbplc_AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesNet",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Accumulated fair value adjustment on items no longer in a hedge relationship",
        "label": "Accumulated fair value hedge adjustment remaining in statement of financial position for hedged item that ceased to be adjusted for hedging gains and losses, liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The accumulated amount of fair value hedge adjustment remaining in the statement of financial position for a hedged item that is a financial liability measured at amortised cost and has ceased to be adjusted for hedging gains and losses. [Refer: Financial liabilities at amortised cost; Hedged items [domain]]"
       }
      }
     },
     "auth_ref": [
      "r263"
     ]
    },
    "bbplc_AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesNet": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AccumulatedFairValueHedgeAdjustmentRemainingInStatementOfFinancialPositionForHedgedItemThatCeasedToBeAdjustedForHedgingGainsAndLossesNet",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Accumulated fair value adjustment on items no longer in a hedge relationship, total",
        "label": "Accumulated Fair Value Hedge Adjustment Remaining In Statement Of Financial Position For Hedged Item That Ceased To Be Adjusted For Hedging Gains And Losses, Net",
        "documentation": "The accumulated amount of fair value hedge adjustment remaining in the statement of financial position for a hedged item that is a financial asset measured at amortised cost less liabilities and has ceased to be adjusted for hedging gains and losses. [Refer: Financial assets at amortised cost; Hedged items [member]]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AccumulatedImpairmentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AccumulatedImpairmentMember",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails",
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Accumulated impairment",
        "netLabel": "Impairment allowance",
        "terseLabel": "Accumulated impairment",
        "label": "Accumulated impairment [member]"
       }
      }
     },
     "auth_ref": [
      "r230",
      "r285",
      "r511",
      "r669",
      "r839",
      "r854",
      "r860",
      "r861"
     ]
    },
    "bbplc_ActiveMembersMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ActiveMembersMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Active members",
        "label": "Active Members [Member]",
        "documentation": "Active Members"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ActuarialAssumptionOfChangeInDiscountRateByFiftyBasisPointsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ActuarialAssumptionOfChangeInDiscountRateByFiftyBasisPointsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "0.5% change in discount rate per annum",
        "label": "Actuarial Assumption Of Change In Discount Rate By Fifty Basis Points [Member]",
        "documentation": "This member stands for Actuarial Assumption Of Change in Discount Rate by Fifty Basis Points."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ActuarialAssumptionOfChangeInDiscountRateByTwentyFiveBasisPointsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ActuarialAssumptionOfChangeInDiscountRateByTwentyFiveBasisPointsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "0.25% change in discount rate per annum",
        "label": "Actuarial Assumption Of Change In Discount Rate By Twenty Five Basis Points [Member]",
        "documentation": "This member stands for Actuarial Assumption Of Change in Discount Rate by Twenty Five Basis Points."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ActuarialAssumptionOfChangeInExpectedInflationRateByFiftyBasisPointsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ActuarialAssumptionOfChangeInExpectedInflationRateByFiftyBasisPointsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "0.5% change in RPI per annum",
        "label": "Actuarial Assumption Of Change In Expected Inflation Rate By Fifty Basis Points [Member]",
        "documentation": "This member stands for Actuarial Assumption Of Change In Expected Inflation Rate By Fifty Basis Points."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ActuarialAssumptionOfChangeInExpectedInflationRateByTwentyFiveBasisPointsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ActuarialAssumptionOfChangeInExpectedInflationRateByTwentyFiveBasisPointsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "0.25% change in RPI per annum",
        "label": "Actuarial Assumption Of Change In Expected Inflation Rate By Twenty Five Basis Points [Member]",
        "documentation": "This member stands for Actuarial Assumption Of Change In Expected Inflation Rate By Twenty Five Basis Points."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ActuarialAssumptionOfChangeInLifeExpectancyAfterRetirementMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ActuarialAssumptionOfChangeInLifeExpectancyAfterRetirementMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Change in life expectancy by one year",
        "label": "Actuarial Assumption Of Change In Life Expectancy After Retirement [Member]",
        "documentation": "This member stands for Actuarial Assumption Of Change In life expectancy by one year."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ActuarialAssumptionOfDiscountRates": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ActuarialAssumptionOfDiscountRates",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Discount rate",
        "label": "Actuarial assumption of discount rates"
       }
      },
      "en": {
       "role": {
        "documentation": "The discount rate used as the significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [domain]]"
       }
      }
     },
     "auth_ref": [
      "r846"
     ]
    },
    "ifrs-full_ActuarialAssumptionOfExpectedRatesOfInflation": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ActuarialAssumptionOfExpectedRatesOfInflation",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Inflation rate (RPI)",
        "label": "Actuarial assumption of expected rates of inflation"
       }
      },
      "en": {
       "role": {
        "documentation": "The expected rate of inflation that is used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [domain]; Defined benefit obligation, at present value; Actuarial assumptions [domain]]"
       }
      }
     },
     "auth_ref": [
      "r846"
     ]
    },
    "bbplc_ActuarialAssumptionOfKeyFinancialAssumptionsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ActuarialAssumptionOfKeyFinancialAssumptionsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Actuarial assumption of key financial assumptions",
        "label": "Actuarial Assumption Of Key Financial Assumptions [member]",
        "documentation": "This member stands for the key financial assumptions related to discount rate and inflation rate used as actuarial assumptions."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ActuarialAssumptionOfLifeExpectancyAfterRetirement": {
     "xbrltype": "durationItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ActuarialAssumptionOfLifeExpectancyAfterRetirement",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assumed life expectancy at 60",
        "label": "Actuarial Assumption Of Life Expectancy After Retirement",
        "documentation": "The life expectancy, expressed in years, after retirement used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [member]]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ActuarialAssumptionsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ActuarialAssumptionsAxis",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Actuarial assumptions [axis]",
        "label": "Actuarial assumptions [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r35"
     ]
    },
    "ifrs-full_ActuarialAssumptionsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ActuarialAssumptionsDomain",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Actuarial assumptions [domain]",
        "label": "Actuarial assumptions [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all actuarial assumptions. Actuarial assumptions are the entity\u2019s unbiased and mutually compatible best estimates of the demographic and financial variables that will determine the ultimate cost of providing post-employment benefits. It also represents the standard value for the 'Actuarial assumptions' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r35"
     ]
    },
    "ifrs-full_ActuarialGainsLossesArisingFromChangesInDemographicAssumptionsNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ActuarialGainsLossesArisingFromChangesInDemographicAssumptionsNetDefinedBenefitLiabilityAsset",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Remeasurement (loss)/gain - demographic",
        "label": "Decrease (increase) in net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in demographic assumptions"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in demographic assumptions that result in remeasurements of the net defined benefit liability (asset). Demographic assumptions deal with matters such as: (a) mortality; (b) rates of employee turnover, disability and early retirement; (c) the proportion of plan members with dependants who will be eligible for benefits; (d) the proportion of plan members who will select each form of payment option available under the plan terms; and (e) claim rates under medical plans. [Refer: Net defined benefit liability (asset)]"
       }
      }
     },
     "auth_ref": [
      "r26"
     ]
    },
    "ifrs-full_ActuarialGainsLossesArisingFromChangesInFinancialAssumptionsNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ActuarialGainsLossesArisingFromChangesInFinancialAssumptionsNetDefinedBenefitLiabilityAsset",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Remeasurement gain - financial",
        "label": "Decrease (increase) in net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in financial assumptions"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in financial assumptions that result in remeasurements of the net defined benefit liability (asset). Financial assumptions deal with items such as: (a) the discount rate; (b) benefit levels, excluding any cost of the benefits to be met by employees, and future salary; (c) in the case of medical benefits, future medical costs, including claim handling costs (ie the costs that will be incurred in processing and resolving claims, including legal and adjuster's fees); and (d) taxes payable by the plan on contributions relating to service before the reporting date or on benefits resulting from that service. [Refer: Net defined benefit liability (asset)]"
       }
      }
     },
     "auth_ref": [
      "r27"
     ]
    },
    "ifrs-full_ActuarialGainsLossesArisingFromExperienceAdjustmentsNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ActuarialGainsLossesArisingFromExperienceAdjustmentsNetDefinedBenefitLiabilityAsset",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Remeasurement loss - experience",
        "label": "Decrease (increase) in net defined benefit liability (asset) resulting from actuarial gains (losses) arising from experience adjustments"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from experience adjustments that result in remeasurements of the net defined benefit liability (asset). Experience adjustments deal with the effects of differences between the previous actuarial assumptions and what has actually occurred. [Refer: Net defined benefit liability (asset)]"
       }
      }
     },
     "auth_ref": [
      "r843"
     ]
    },
    "ecd_Additional402vDisclosureTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "Additional402vDisclosureTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Additional 402(v) Disclosure [Text Block]",
        "terseLabel": "Additional 402(v) Disclosure"
       }
      }
     },
     "auth_ref": [
      "r772"
     ]
    },
    "ifrs-full_AdditionalProvisionsOtherProvisions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdditionalProvisionsOtherProvisions",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Additions",
        "label": "Additional provisions, other provisions"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of additional other provisions made. [Refer: Other provisions]"
       }
      }
     },
     "auth_ref": [
      "r92",
      "r442"
     ]
    },
    "bbplc_AdditionalTier1SecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AdditionalTier1SecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT1 Securities",
        "verboseLabel": "AT1 equity instruments",
        "label": "Additional Tier 1 Securities [Member]",
        "documentation": "This member stands for Additional Tier one securities. They are perpetual securities with no fixed maturity and are structured to qualify as AT1 instruments under CRR as amended by CRR II. They are non-common equity securities that are eligible as AT1 capital."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_AdditionsIntangibleAssetsAndGoodwill": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AdditionsIntangibleAssetsAndGoodwill",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Additions",
        "label": "Additions, Intangible Assets And Goodwill",
        "documentation": "Additions, Intangible Assets And Goodwill"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AdditionsOtherThanThroughBusinessCombinationsPropertyPlantAndEquipmentIncludingRightofuseAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdditionsOtherThanThroughBusinessCombinationsPropertyPlantAndEquipmentIncludingRightofuseAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Additions",
        "label": "Additions other than through business combinations, property, plant and equipment including right-of-use assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of additions to property, plant and equipment including right-of-use assets other than those acquired through business combinations. [Refer: Total for all business combinations [member]; Property, plant and equipment including right-of-use assets]"
       }
      }
     },
     "auth_ref": [
      "r840"
     ]
    },
    "dei_AddressTypeDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "AddressTypeDomain",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Address Type [Domain]",
        "label": "Address Type [Domain]",
        "documentation": "An entity may have several addresses for different purposes and this domain represents all such types."
       }
      }
     },
     "auth_ref": []
    },
    "ecd_AdjToCompAmt": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AdjToCompAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Adjustment to Compensation Amount",
        "terseLabel": "Adjustment to Compensation, Amount"
       }
      }
     },
     "auth_ref": [
      "r785"
     ]
    },
    "ecd_AdjToCompAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AdjToCompAxis",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Adjustment to Compensation [Axis]",
        "terseLabel": "Adjustment to Compensation:"
       }
      }
     },
     "auth_ref": [
      "r785"
     ]
    },
    "ecd_AdjToNonPeoNeoCompFnTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AdjToNonPeoNeoCompFnTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Adjustment to Non-PEO NEO Compensation Footnote [Text Block]",
        "terseLabel": "Adjustment to Non-PEO NEO Compensation Footnote"
       }
      }
     },
     "auth_ref": [
      "r785"
     ]
    },
    "ecd_AdjToPeoCompFnTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AdjToPeoCompFnTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Adjustment To PEO Compensation, Footnote [Text Block]",
        "terseLabel": "Adjustment To PEO Compensation, Footnote"
       }
      }
     },
     "auth_ref": [
      "r785"
     ]
    },
    "bbplc_AdjustmentForNonCashItemsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AdjustmentForNonCashItemsAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Adjustment for non-cash items:",
        "label": "Adjustment For Non-Cash Items [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AdjustmentToMidmarketConsensusPriceMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentToMidmarketConsensusPriceMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Comparable price",
        "label": "Adjustment to mid-market consensus price, measurement input [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for an adjustment to mid-market consensus price, used as a measurement input."
       }
      }
     },
     "auth_ref": [
      "r645"
     ]
    },
    "ifrs-full_AdjustmentsForCurrentTaxOfPriorPeriod": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForCurrentTaxOfPriorPeriod",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails": {
       "parentTag": "ifrs-full_CurrentTaxExpenseIncomeAndAdjustmentsForCurrentTaxOfPriorPeriods",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Adjustments in respect of prior years",
        "label": "Adjustments for current tax of prior periods"
       }
      }
     },
     "auth_ref": [
      "r607",
      "r701"
     ]
    },
    "ifrs-full_AdjustmentsForDecreaseIncreaseInFinancialAssetsHeldForTrading": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForDecreaseIncreaseInFinancialAssetsHeldForTrading",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 13.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net (increase)/decrease in trading portfolio assets",
        "label": "Adjustments for decrease (increase) in financial assets held for trading"
       }
      },
      "en": {
       "role": {
        "documentation": "Adjustments for decrease (increase) in financial assets held for trading to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Financial assets; Financial assets at fair value through profit or loss, classified as held for trading; Profit (loss)]"
       }
      }
     },
     "auth_ref": [
      "r867"
     ]
    },
    "ifrs-full_AdjustmentsForDecreaseIncreaseInLoansAndAdvances": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForDecreaseIncreaseInLoansAndAdvances",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 19.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net (increase)/decrease in loans and advances at amortised cost",
        "verboseLabel": "Net (increase)/decrease in loans and advances at amortised cost",
        "label": "Adjustments for decrease (increase) in loans and advances"
       }
      },
      "en": {
       "role": {
        "documentation": "Adjustments for decrease (increase) in loans and advances to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Loans and advances; Profit (loss)]"
       }
      }
     },
     "auth_ref": [
      "r867"
     ]
    },
    "ifrs-full_AdjustmentsForDecreaseIncreaseInOtherAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForDecreaseIncreaseInOtherAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 16.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net increase in other assets",
        "verboseLabel": "Net (increase)/decrease in other assets",
        "label": "Adjustments for decrease (increase) in other assets"
       }
      },
      "en": {
       "role": {
        "documentation": "Adjustments for decrease (increase) in other assets to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Other assets; Profit (loss)]"
       }
      }
     },
     "auth_ref": [
      "r867"
     ]
    },
    "ifrs-full_AdjustmentsForDecreaseIncreaseInReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForDecreaseIncreaseInReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 8.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net (decrease)/increase in repurchase agreements and other similar secured borrowing",
        "label": "Adjustments for decrease (increase) in reverse repurchase agreements and cash collateral on securities borrowed"
       }
      },
      "en": {
       "role": {
        "documentation": "Adjustments for decrease (increase) in reverse repurchase agreements and cash collateral on securities borrowed to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Reverse repurchase agreements and cash collateral on securities borrowed; Profit (loss)]"
       }
      }
     },
     "auth_ref": [
      "r867"
     ]
    },
    "ifrs-full_AdjustmentsForDecreaseIncreaseInTradeAccountReceivable": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForDecreaseIncreaseInTradeAccountReceivable",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 7.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net decrease in cash collateral and settlement balances",
        "verboseLabel": "Net decrease in cash collateral and settlement balances",
        "label": "Adjustments for decrease (increase) in trade accounts receivable"
       }
      }
     },
     "auth_ref": [
      "r865"
     ]
    },
    "ifrs-full_AdjustmentsForDeferredTaxOfPriorPeriods": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForDeferredTaxOfPriorPeriods",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails": {
       "parentTag": "ifrs-full_DeferredTaxExpenseIncomeRecognisedInProfitOrLoss",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Adjustments in respect of prior years",
        "label": "Adjustments for deferred tax of prior periods"
       }
      }
     },
     "auth_ref": [
      "r835"
     ]
    },
    "ifrs-full_AdjustmentsForDepreciationAndAmortisationExpenseAndImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForDepreciationAndAmortisationExpenseAndImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Depreciation, amortisation and impairment of property, plant, equipment and intangibles",
        "label": "Adjustments for depreciation and amortisation expense and impairment loss (reversal of impairment loss) recognised in profit or loss"
       }
      }
     },
     "auth_ref": [
      "r867"
     ]
    },
    "ifrs-full_AdjustmentsForFairValueGainsLosses": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForFairValueGainsLosses",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 15.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net increase/(decrease) in financial assets and liabilities at fair value through the income statement",
        "label": "Adjustments for fair value losses (gains)"
       }
      }
     },
     "auth_ref": [
      "r866"
     ]
    },
    "ifrs-full_AdjustmentsForGainsLossesOnChangeInFairValueOfDerivatives": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForGainsLossesOnChangeInFairValueOfDerivatives",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": -1.0,
       "order": 12.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Net decrease/(increase) in derivative financial instruments",
        "negatedTerseLabel": "Net (increase)/decrease in derivative financial instruments",
        "label": "Adjustments for gains (losses) on change in fair value of derivatives"
       }
      },
      "en": {
       "role": {
        "documentation": "Adjustments for gains (losses) on changes in the fair value of derivatives to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: At fair value [member]; Derivatives [member]; Profit (loss)]"
       }
      }
     },
     "auth_ref": [
      "r867"
     ]
    },
    "ifrs-full_AdjustmentsForImpairmentLossesReversalOfImpairmentLossesRecognisedInProfitOrLossFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForImpairmentLossesReversalOfImpairmentLossesRecognisedInProfitOrLossFinancialAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Credit impairment charges",
        "terseLabel": "Credit impairment charges",
        "label": "Adjustments for impairment losses (reversal of impairment losses) recognised in profit or loss, financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "Adjustments for impairment losses (reversal of impairment losses) on financial assets recognised in profit or loss to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Adjustments for impairment loss (reversal of impairment loss) recognised in profit or loss]"
       }
      }
     },
     "auth_ref": [
      "r867"
     ]
    },
    "ifrs-full_AdjustmentsForIncreaseDecreaseInDebtInstrumentsIssued": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForIncreaseDecreaseInDebtInstrumentsIssued",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 10.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net increase/(decrease) in debt securities in issue",
        "verboseLabel": "Net increase/(decrease) in debt securities in issue",
        "label": "Adjustments for increase (decrease) in debt instruments issued"
       }
      },
      "en": {
       "role": {
        "documentation": "Adjustments for increase (decrease) in debt instruments issued to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Debt instruments issued; Profit (loss)]"
       }
      }
     },
     "auth_ref": [
      "r867"
     ]
    },
    "ifrs-full_AdjustmentsForIncreaseDecreaseInDeposits": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForIncreaseDecreaseInDeposits",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 9.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net increase in deposits at amortised cost",
        "label": "Adjustments for increase (decrease) in deposits"
       }
      },
      "en": {
       "role": {
        "documentation": "Adjustments for increase (decrease) in deposit liabilities to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Deposit liabilities; Profit (loss)]"
       }
      }
     },
     "auth_ref": [
      "r867"
     ]
    },
    "ifrs-full_AdjustmentsForIncreaseDecreaseInFinancialLiabilitiesHeldForTrading": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForIncreaseDecreaseInFinancialLiabilitiesHeldForTrading",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 14.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net increase/(decrease) in trading portfolio liabilities",
        "verboseLabel": "Net decrease in trading portfolio liabilities",
        "label": "Adjustments for increase (decrease) in financial liabilities held for trading"
       }
      },
      "en": {
       "role": {
        "documentation": "Adjustments for increase (decrease) in financial liabilities held for trading to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Financial liabilities; Financial liabilities at fair value through profit or loss that meet definition of held for trading; Profit (loss)]"
       }
      }
     },
     "auth_ref": [
      "r867"
     ]
    },
    "ifrs-full_AdjustmentsForIncreaseDecreaseInOtherLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForIncreaseDecreaseInOtherLiabilities",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 17.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net decrease in other liabilities",
        "verboseLabel": "Net decrease in other liabilities",
        "label": "Adjustments for increase (decrease) in other liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "Adjustments for increase (decrease) in other liabilities to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Other liabilities; Profit (loss)]"
       }
      }
     },
     "auth_ref": [
      "r867"
     ]
    },
    "ifrs-full_AdjustmentsForIncreaseDecreaseInRepurchaseAgreementsAndCashCollateralOnSecuritiesLent": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForIncreaseDecreaseInRepurchaseAgreementsAndCashCollateralOnSecuritiesLent",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 11.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Net increase in reverse repurchase agreements and other similar secured lending",
        "terseLabel": "Net (increase)/decrease in reverse repurchase agreements and other similar secured lending",
        "label": "Adjustments for increase (decrease) in repurchase agreements and cash collateral on securities lent"
       }
      },
      "en": {
       "role": {
        "documentation": "Adjustments for increase (decrease) in repurchase agreements and cash collateral on securities lent to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Repurchase agreements and cash collateral on securities lent; Profit (loss)]"
       }
      }
     },
     "auth_ref": [
      "r867"
     ]
    },
    "ifrs-full_AdjustmentsForLossesGainsOnDisposalOfNoncurrentAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForLossesGainsOnDisposalOfNoncurrentAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Net loss on disposal of investments and property, plant and equipment",
        "terseLabel": "Net (profit)/loss on disposal of investments and property, plant and equipment",
        "label": "Adjustments for losses (gains) on disposal of non-current assets"
       }
      }
     },
     "auth_ref": [
      "r862"
     ]
    },
    "ifrs-full_AdjustmentsForProvisions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForProvisions",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Provisions and pension charges",
        "verboseLabel": "Provisions and pensions charges/(credits)",
        "label": "Adjustments for provisions"
       }
      }
     },
     "auth_ref": [
      "r866"
     ]
    },
    "ifrs-full_AdjustmentsForReconcileProfitLossAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsForReconcileProfitLossAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation of profit before tax to net cash flows from operating activities:",
        "label": "Adjustments to reconcile profit (loss) [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_AdjustmentsInRespectOfPriorYears": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AdjustmentsInRespectOfPriorYears",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Adjustments in respect of prior years",
        "label": "Adjustments In Respect Of Prior Years",
        "documentation": "The adjustments of tax expense (income) recognised in the period for current and deferred tax of prior periods."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_AdjustmentsInRespectOfPriorYearsPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AdjustmentsInRespectOfPriorYearsPercentage",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Adjustments in respect of prior years, percentage",
        "label": "Adjustments In Respect Of Prior Years, Percentage",
        "documentation": "The tax rate effect of adjustments for current and deferred tax of prior periods, expressed as a percentage."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AdjustmentsToReconcileProfitLossAttributableToOwnersOfParentToNumeratorUsedInCalculatingBasicEarningsPerShare": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AdjustmentsToReconcileProfitLossAttributableToOwnersOfParentToNumeratorUsedInCalculatingBasicEarningsPerShare",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntity",
       "weight": -1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other equity instrument holders",
        "label": "Adjustments to reconcile profit (loss) attributable to owners of parent to numerator used in calculating basic earnings per share"
       }
      },
      "en": {
       "role": {
        "documentation": "The adjustment to reconcile profit (loss) attributable to the parent entity to the numerator used in calculating basic earnings per share. It represents the aggregate of the reconciliation amounts for all classes of instruments that affect basic earnings per share."
       }
      }
     },
     "auth_ref": [
      "r68"
     ]
    },
    "bbplc_AfricaAndMiddleEastMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AfricaAndMiddleEastMember",
     "presentation": [
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Africa and Middle East",
        "label": "Africa And Middle East [Member]",
        "documentation": "This member stands for Africa and the middle east."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AggregateDifferenceBetweenFairValueAtInitialRecognitionAndAmountDeterminedUsingValuationTechniqueYetToBeRecognised": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AggregateDifferenceBetweenFairValueAtInitialRecognitionAndAmountDeterminedUsingValuationTechniqueYetToBeRecognised",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Difference between initial FV and transaction price to be recognised in profit or loss",
        "label": "Aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss"
       }
      },
      "en": {
       "role": {
        "documentation": "The aggregate difference between the fair value at initial recognition and the transaction price for financial instruments that is yet to be recognised in profit or loss. [Refer: Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r275",
      "r504"
     ]
    },
    "bbplc_AggregateEmolumentsCompaniesAct2006": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AggregateEmolumentsCompaniesAct2006",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details": {
       "parentTag": "bbplc_DirectorsExpenseCompaniesAct2006",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Aggregate emoluments",
        "label": "Aggregate Emoluments Companies Act 2006",
        "documentation": "The amount of emoluments for directors is presented in accordance with the companies act 2006."
       }
      }
     },
     "auth_ref": []
    },
    "ecd_AggtChngPnsnValInSummryCompstnTblForAplblYrMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AggtChngPnsnValInSummryCompstnTblForAplblYrMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member]",
        "terseLabel": "Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table"
       }
      }
     },
     "auth_ref": [
      "r830"
     ]
    },
    "ecd_AggtErrCompAmt": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AggtErrCompAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Aggregate Erroneous Compensation Amount",
        "terseLabel": "Aggregate Erroneous Compensation Amount"
       }
      }
     },
     "auth_ref": [
      "r743",
      "r754",
      "r764",
      "r797"
     ]
    },
    "ecd_AggtErrCompNotYetDeterminedTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AggtErrCompNotYetDeterminedTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Aggregate Erroneous Compensation Not Yet Determined [Text Block]",
        "terseLabel": "Aggregate Erroneous Compensation Not Yet Determined"
       }
      }
     },
     "auth_ref": [
      "r746",
      "r757",
      "r767",
      "r800"
     ]
    },
    "ecd_AggtPnsnAdjsSvcCstMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AggtPnsnAdjsSvcCstMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Aggregate Pension Adjustments Service Cost [Member]",
        "terseLabel": "Aggregate Pension Adjustments Service Cost"
       }
      }
     },
     "auth_ref": [
      "r831"
     ]
    },
    "bbplc_AgricultureFoodAndForestProductsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AgricultureFoodAndForestProductsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Agriculture, Food and Forest Products",
        "label": "Agriculture, Food And Forest Products [Member]",
        "documentation": "Agriculture, Food And Forest Products"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_AllAdjToCompMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AllAdjToCompMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "All Adjustments to Compensation [Member]",
        "terseLabel": "All Adjustments to Compensation"
       }
      }
     },
     "auth_ref": [
      "r785"
     ]
    },
    "currency_AllCurrenciesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/currency/2025",
     "localname": "AllCurrenciesDomain",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "All Currencies [Domain]",
        "label": "All Currencies [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_AllExecutiveCategoriesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AllExecutiveCategoriesMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "All Executive Categories [Member]",
        "terseLabel": "All Executive Categories"
       }
      }
     },
     "auth_ref": [
      "r792"
     ]
    },
    "ecd_AllIndividualsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AllIndividualsMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure",
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure",
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements",
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "All Individuals [Member]",
        "terseLabel": "All Individuals"
       }
      }
     },
     "auth_ref": [
      "r747",
      "r758",
      "r768",
      "r792",
      "r801",
      "r805",
      "r813"
     ]
    },
    "ecd_AllTradingArrangementsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AllTradingArrangementsMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "All Trading Arrangements [Member]",
        "terseLabel": "All Trading Arrangements"
       }
      }
     },
     "auth_ref": [
      "r811"
     ]
    },
    "ifrs-full_AllowanceForCreditLossesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AllowanceForCreditLossesMember",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loan impairment allowance",
        "label": "Allowance for credit losses [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for an allowance account used to record impairments to financial assets due to credit losses."
       }
      }
     },
     "auth_ref": [
      "r836"
     ]
    },
    "dei_AmendmentFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "AmendmentFlag",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Amendment Flag",
        "label": "Amendment Flag",
        "documentation": "Boolean flag that is true when the XBRL content amends previously-filed or accepted submission."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_AmericanAirlinesPortfolioMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AmericanAirlinesPortfolioMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "American Airlines Portfolio",
        "label": "American Airlines Portfolio [Member]",
        "documentation": "American Airlines Portfolio"
       }
      }
     },
     "auth_ref": []
    },
    "srt_AmericasMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "AmericasMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Americas",
        "label": "Americas [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AmortisationAssetsRecognisedFromCostsIncurredToObtainOrFulfilContractsWithCustomers": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AmortisationAssetsRecognisedFromCostsIncurredToObtainOrFulfilContractsWithCustomers",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Amortisation, capitalised contract costs",
        "label": "Amortisation, assets recognised from costs incurred to obtain or fulfil contracts with customers"
       }
      }
     },
     "auth_ref": [
      "r186",
      "r362"
     ]
    },
    "ifrs-full_AmortisationIntangibleAssetsOtherThanGoodwill": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AmortisationIntangibleAssetsOtherThanGoodwill",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Amortisation charge",
        "label": "Amortisation, intangible assets other than goodwill"
       }
      }
     },
     "auth_ref": [
      "r102",
      "r451"
     ]
    },
    "ifrs-full_AmountByWhichFinancialAssetsRelatedCreditDerivativesOrSimilarInstrumentsMitigateMaximumExposureToCreditRisk": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AmountByWhichFinancialAssetsRelatedCreditDerivativesOrSimilarInstrumentsMitigateMaximumExposureToCreditRisk",
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Value mitigated by related credit derivatives, maximum exposure",
        "label": "Amount by which credit derivatives or similar instruments related to financial assets designated as measured at fair value through profit or loss mitigate maximum exposure to credit risk"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount by which credit derivatives or similar instruments related to financial assets designated as measured at fair value through profit or loss mitigate maximum exposure to credit risk. [Refer: Loans and receivables; Credit risk [member]; Derivatives [member]; Maximum exposure to credit risk; Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r320"
     ]
    },
    "ifrs-full_AmountByWhichUnitsRecoverableAmountExceedsItsCarryingAmount": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AmountByWhichUnitsRecoverableAmountExceedsItsCarryingAmount",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails": {
       "parentTag": "ifrs-full_RecoverableAmountOfAssetOrCashgeneratingUnit",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Value in use exceeding carrying value",
        "verboseLabel": "Value in use exceeding carrying value",
        "label": "Amount by which unit's recoverable amount exceeds its carrying amount"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount by which a cash-generating unit's (group of units') recoverable amount exceeds its carrying amount. [Refer: Carrying amount [member]; Total for all cash-generating units [member]]"
       }
      }
     },
     "auth_ref": [
      "r84",
      "r88"
     ]
    },
    "ifrs-full_AmountByWhichValueAssignedToKeyAssumptionMustChangeInOrderForUnitsRecoverableAmountToBeEqualToCarryingAmount": {
     "xbrltype": "decimalItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AmountByWhichValueAssignedToKeyAssumptionMustChangeInOrderForUnitsRecoverableAmountToBeEqualToCarryingAmount",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Change required to reduce headroom to zero",
        "label": "Amount by which value assigned to key assumption must change in order for unit's recoverable amount to be equal to carrying amount"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount by which value that has been assigned to a key assumption must change in order for a unit's recoverable amount to be equal to its carrying amount. [Refer: Carrying amount [member]]"
       }
      }
     },
     "auth_ref": [
      "r85",
      "r89"
     ]
    },
    "bbplc_AmountsNotSubjectToEnforceableNettingArrangements": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AmountsNotSubjectToEnforceableNettingArrangements",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": "ifrs-full_DerivativeFinancialLiabilities",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Amounts not subject to enforceable netting arrangements",
        "label": "Amounts Not Subject To Enforceable Netting Arrangements",
        "documentation": "The financial liabilities that are not subject to an enforceable master netting arrangement or similar agreement."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_AmountsPaidUnderLTIPsCompaniesAct2006": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AmountsPaidUnderLTIPsCompaniesAct2006",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details": {
       "parentTag": "bbplc_DirectorsExpenseCompaniesAct2006",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Amounts paid under LTIPs",
        "label": "Amounts Paid Under LTIPs Companies Act 2006",
        "documentation": "The amount paid under LTIPs for directors is presented in accordance with the companies act 2006."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AmountsPayableRelatedPartyTransactions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AmountsPayableRelatedPartyTransactions",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequityParenthetical",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofloansanddepositsoutstandingDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Amounts payable, related party transactions",
        "netLabel": "Deposits outstanding as at 31 December",
        "label": "Amounts payable, related party transactions"
       }
      },
      "en": {
       "role": {
        "documentation": "The amounts payable resulting from related party transactions. [Refer: Total for all related parties [member]]"
       }
      }
     },
     "auth_ref": [
      "r50",
      "r59",
      "r421"
     ]
    },
    "ifrs-full_AmountsReceivableRelatedPartyTransactions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AmountsReceivableRelatedPartyTransactions",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofloansanddepositsoutstandingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans outstanding as at 31 December",
        "label": "Amounts receivable, related party transactions"
       }
      },
      "en": {
       "role": {
        "documentation": "The amounts receivable resulting from related party transactions. [Refer: Total for all related parties [member]]"
       }
      }
     },
     "auth_ref": [
      "r50",
      "r59",
      "r421"
     ]
    },
    "ifrs-full_AmountsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssetsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AmountsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssetsAbstract",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Amounts subject to enforceable master netting arrangement or similar agreement not set off against financial assets [abstract]",
        "label": "Amounts subject to enforceable master netting arrangement or similar agreement not set off against financial assets [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AmountsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AmountsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilitiesAbstract",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Amounts subject to enforceable master netting arrangement or similar agreement not set off against financial liabilities [abstract]",
        "label": "Amounts subject to enforceable master netting arrangement or similar agreement not set off against financial liabilities [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AnalysisOfIncomeAndExpenseAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AnalysisOfIncomeAndExpenseAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Analysis of income and expense [abstract]",
        "label": "Analysis of income and expense [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ApplicableTaxRate": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ApplicableTaxRate",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "UK Corporation tax rate",
        "label": "Applicable tax rate"
       }
      },
      "en": {
       "role": {
        "documentation": "The applicable income tax rate."
       }
      }
     },
     "auth_ref": [
      "r5",
      "r393"
     ]
    },
    "srt_AsiaMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "AsiaMember",
     "presentation": [
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Asia",
        "label": "Asia [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_AssetBackedFundingProgrammesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AssetBackedFundingProgrammesMember",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Asset backed funding programmes",
        "label": "Asset Backed Funding Programmes [Member]",
        "documentation": "This member stands for asset-backed funding programmes that can readily be used to raise additional secured funding and are available to support future issuance."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AssetbackedFinancingsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetbackedFinancingsMember",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureofcontinuinginvolvementinfinancialassetsthathavebeenderecognisedDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Secured financing",
        "verboseLabel": "Asset backed securities",
        "label": "Asset-backed financings [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for asset-backed financings."
       }
      }
     },
     "auth_ref": [
      "r637"
     ]
    },
    "ifrs-full_Assets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "Assets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails": {
       "parentTag": "ifrs-full_MaximumExposureToLossFromInterestsInStructuredEntities",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      },
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofamountsincludedintheGroupsfinancialstatementsbycategoryDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails",
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total assets",
        "verboseLabel": "Total assets",
        "terseLabel": "Assets",
        "label": "Assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of a present economic resource controlled by the entity as a result of past events. Economic resource is a right that has the potential to produce economic benefits."
       }
      }
     },
     "auth_ref": [
      "r162",
      "r163",
      "r170",
      "r335",
      "r338",
      "r530",
      "r531",
      "r575"
     ]
    },
    "ifrs-full_AssetsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Assets",
        "terseLabel": "Assets",
        "label": "Assets [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AssetsAndLiabilitiesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsAndLiabilitiesAxis",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets and liabilities [axis]",
        "label": "Assets and liabilities [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r42",
      "r389",
      "r417",
      "r541",
      "r559"
     ]
    },
    "ifrs-full_AssetsAndLiabilitiesClassifiedAsHeldForSaleAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsAndLiabilitiesClassifiedAsHeldForSaleAxis",
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets and liabilities classified as held for sale [axis]",
        "label": "Assets and liabilities classified as held for sale [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r234"
     ]
    },
    "ifrs-full_AssetsAndLiabilitiesClassifiedAsHeldForSaleMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsAndLiabilitiesClassifiedAsHeldForSaleMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets and liabilities classified as held for sale",
        "verboseLabel": "Non-current assets/liabilities held for sale",
        "label": "Assets and liabilities classified as held for sale [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for assets and liabilities that are classified as held for sale. [Refer: Non-current assets held for sale [member]; Liabilities included in disposal groups classified as held for sale; Disposal groups classified as held for sale [member]]"
       }
      }
     },
     "auth_ref": [
      "r234"
     ]
    },
    "ifrs-full_AssetsAndLiabilitiesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsAndLiabilitiesDomain",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets and liabilities [domain]",
        "label": "Assets and liabilities [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for assets and liabilities. It also represents the standard value for the 'Assets and liabilities' axis if no other member is used. [Refer: Assets; Liabilities]"
       }
      }
     },
     "auth_ref": [
      "r42",
      "r389",
      "r417",
      "r541",
      "r559"
     ]
    },
    "ifrs-full_AssetsAndLiabilitiesNotClassifiedAsHeldForSaleMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsAndLiabilitiesNotClassifiedAsHeldForSaleMember",
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets and liabilities not classified as held for sale [member]",
        "label": "Assets and liabilities not classified as held for sale [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for assets and liabilities that are not classified as held for sale. It also represents the standard value for the 'Assets and liabilities classified as held for sale' axis if no other member is used. [Refer: Non-current assets held for sale [member]; Liabilities included in disposal groups classified as held for sale; Disposal groups classified as held for sale [member]]"
       }
      }
     },
     "auth_ref": [
      "r234"
     ]
    },
    "bbplc_AssetsByFunctionsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AssetsByFunctionsAxis",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets By Functions [Axis]",
        "label": "Assets By Functions [Axis]",
        "documentation": "Assets By Functions"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_AssetsByFunctionsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AssetsByFunctionsDomain",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets By Functions [Domain]",
        "label": "Assets By Functions [Domain]",
        "documentation": "Assets By Functions [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AssetsHeldAsCollateralPermittedToBeSoldOrRepledgedAtFairValue": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsHeldAsCollateralPermittedToBeSoldOrRepledgedAtFairValue",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcollateralheldassecurityforassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fair value of securities accepted as collateral",
        "label": "Collateral held permitted to be sold or repledged in absence of default by owner of collateral, at fair value"
       }
      },
      "en": {
       "role": {
        "documentation": "The fair value of collateral held that is permitted to be sold or repledged in the absence of default by the owner of the collateral. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r245"
     ]
    },
    "ifrs-full_AssetsLiabilitiesOfBenefitPlan": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsLiabilitiesOfBenefitPlan",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "lang": {
      "en": {
       "role": {
        "documentation": "The amount of assets of a retirement benefit plan less liabilities other than the actuarial present value of promised retirement benefits."
       }
      }
     },
     "auth_ref": [
      "r61"
     ]
    },
    "bbplc_AssetsPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AssetsPercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total assets, percentage",
        "label": "Assets, Percentage",
        "documentation": "The amount of resources, expressed as a percentage: (a) controlled by the entity as a result of past events; and (b) from which future economic benefits are expected to flow to the entity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_AssetsPledgedCollateralReceivedAndAssetsTransferredAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AssetsPledgedCollateralReceivedAndAssetsTransferredAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "38. Assets pledged, collateral received and assets transferred",
        "label": "Assets Pledged, Collateral Received And Assets Transferred [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AssetsRecognisedFromCostsToObtainOrFulfilContractsWithCustomers": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsRecognisedFromCostsToObtainOrFulfilContractsWithCustomers",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Capitalised contract costs",
        "label": "Assets recognised from costs to obtain or fulfil contracts with customers"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of assets recognised from the costs to obtain or fulfil contracts with customers. The costs to obtain a contract with a customer are the incremental costs of obtaining the contract that the entity would not have incurred if the contract had not been obtained. The costs to fulfil a contract with a customer are the costs that relate directly to a contract or to an anticipated contract that the entity can specifically identify."
       }
      }
     },
     "auth_ref": [
      "r185",
      "r361"
     ]
    },
    "ifrs-full_AssetsRecognisedInEntitysFinancialStatementsInRelationToStructuredEntities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsRecognisedInEntitysFinancialStatementsInRelationToStructuredEntities",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total assets of the entity",
        "label": "Assets recognised in entity's financial statements in relation to structured entities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of assets recognised in the entity's financial statements relating to its interests in structured entities. [Refer: Assets; Total for all unconsolidated structured entities [member]]"
       }
      }
     },
     "auth_ref": [
      "r145"
     ]
    },
    "ifrs-full_AssetsSoldOrRepledgedAsCollateralAtFairValue": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsSoldOrRepledgedAsCollateralAtFairValue",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcollateralheldassecurityforassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Of which fair value of securities re-pledged/transferred to others",
        "label": "Collateral sold or repledged in absence of default by owner of collateral, at fair value"
       }
      },
      "en": {
       "role": {
        "documentation": "The fair value of collateral sold or repledged that was permitted to be sold or repledged in the absence of default by the owner of the collateral. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r246"
     ]
    },
    "ifrs-full_AssetsThatEntityContinuesToRecognise": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsThatEntityContinuesToRecognise",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails",
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureoftransferredfinancialassetsandtheassociatedliabilitiesDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets, carrying amount",
        "verboseLabel": "Transferred assets",
        "label": "Assets that entity continues to recognise"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of transferred financial assets that the entity continues to recognise in full. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r301",
      "r520"
     ]
    },
    "ifrs-full_AssetsThatEntityContinuesToRecogniseToExtentOfContinuingInvolvement": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsThatEntityContinuesToRecogniseToExtentOfContinuingInvolvement",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets that entity continues to recognise to extent of continuing involvement",
        "label": "Assets that entity continues to recognise to extent of continuing involvement"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of transferred financial assets that the entity continues to recognise to the extent of its continuing involvement. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r302"
     ]
    },
    "ifrs-full_AssetsTransferredToStructuredEntitiesAtTimeOfTransfer": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssetsTransferredToStructuredEntitiesAtTimeOfTransfer",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets transferred to sponsored unconsolidated structured entities",
        "label": "Assets transferred to structured entities, at time of transfer"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount, at the time of transfer, of all assets transferred to structured entities. [Refer: Total for all unconsolidated structured entities [member]]"
       }
      }
     },
     "auth_ref": [
      "r144"
     ]
    },
    "ifrs-full_AssociatedLiabilitiesThatEntityContinuesToRecognise": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssociatedLiabilitiesThatEntityContinuesToRecognise",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails",
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureoftransferredfinancialassetsandtheassociatedliabilitiesDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Liabilities, carrying amount",
        "negatedLabel": "Associated liabilities",
        "label": "Associated liabilities that entity continues to recognise"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of liabilities associated with transferred financial assets that the entity continues to recognise in full. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r301",
      "r520"
     ]
    },
    "ifrs-full_AssociatesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AssociatesMember",
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofamountsincludedintheGroupsfinancialstatementsbycategoryDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Associates",
        "verboseLabel": "Other related parties",
        "label": "Total for all associates [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the entities over which the investor has significant influence."
       }
      }
     },
     "auth_ref": [
      "r55",
      "r65",
      "r67",
      "r159",
      "r425",
      "r524"
     ]
    },
    "bbplc_AssumptionForFutureInflationIncreaseDecrease": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AssumptionForFutureInflationIncreaseDecrease",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assumption for future inflation increase (decrease)",
        "label": "Assumption For Future Inflation Increase (Decrease)",
        "documentation": "Assumption For Future Inflation Increase (Decrease)"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_AssumptionForFutureMortalityImprovementsPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AssumptionForFutureMortalityImprovementsPercentage",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Future mortality improvement percentage",
        "label": "Assumption For Future Mortality Improvements, Percentage",
        "documentation": "Assumption For Future Mortality Improvements, Percentage"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AtFairValueMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AtFairValueMember",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "At fair value",
        "verboseLabel": "Carried at fair value",
        "label": "At fair value [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for measurement based on fair value. Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date."
       }
      }
     },
     "auth_ref": [
      "r111",
      "r115",
      "r142",
      "r162",
      "r457",
      "r527",
      "r530"
     ]
    },
    "bbplc_AuditFeeRelatingToPreviousYearMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AuditFeeRelatingToPreviousYearMember",
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Audit fee relating to previous year",
        "label": "Audit Fee Relating To Previous Year [Member]",
        "documentation": "Audit Fee Relating To Previous Year"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_AuditInformationAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AuditInformationAbstract",
     "lang": {
      "en-us": {
       "role": {
        "label": "Audit Information [Abstract]",
        "documentation": "Audit Information [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "dei_AuditorFirmId": {
     "xbrltype": "nonemptySequenceNumberItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "AuditorFirmId",
     "presentation": [
      "http://www.home.barclays/role/AuditInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Auditor Firm ID",
        "label": "Auditor Firm ID",
        "documentation": "PCAOB issued Audit Firm Identifier"
       }
      }
     },
     "auth_ref": [
      "r726",
      "r727",
      "r750"
     ]
    },
    "dei_AuditorLocation": {
     "xbrltype": "internationalNameItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "AuditorLocation",
     "presentation": [
      "http://www.home.barclays/role/AuditInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Auditor Location",
        "label": "Auditor Location"
       }
      }
     },
     "auth_ref": [
      "r726",
      "r727",
      "r750"
     ]
    },
    "dei_AuditorName": {
     "xbrltype": "internationalNameItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "AuditorName",
     "presentation": [
      "http://www.home.barclays/role/AuditInformation"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Auditor Name",
        "label": "Auditor Name"
       }
      }
     },
     "auth_ref": [
      "r726",
      "r727",
      "r750"
     ]
    },
    "ifrs-full_AuditorsRemuneration": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AuditorsRemuneration",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total Auditor's remuneration",
        "label": "Auditor's remuneration"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "ifrs-full_AuditorsRemunerationAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AuditorsRemunerationAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Auditor's remuneration [abstract]",
        "label": "Auditor's remuneration [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AuditorsRemunerationForAuditServices": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AuditorsRemunerationForAuditServices",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails": {
       "parentTag": "ifrs-full_AuditorsRemuneration",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails",
      "http://www.home.barclays/role/AuditorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Audit and audit related fees",
        "terseLabel": "Audit and audit related fees",
        "label": "Auditor's remuneration for audit services"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "ifrs-full_AuditorsRemunerationForOtherServices": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AuditorsRemunerationForOtherServices",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails": {
       "parentTag": "ifrs-full_AuditorsRemuneration",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails",
      "http://www.home.barclays/role/AuditorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Other services",
        "terseLabel": "Other services",
        "label": "Auditor's remuneration for other services"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "ifrs-full_AuditorsRemunerationForTaxServices": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AuditorsRemunerationForTaxServices",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Tax fees",
        "label": "Auditor's remuneration for tax services"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "ifrs-full_AverageEffectiveTaxRate": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AverageEffectiveTaxRate",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total tax charge, percentage",
        "terseLabel": "Effective tax rate",
        "label": "Average effective tax rate"
       }
      },
      "en": {
       "role": {
        "documentation": "The tax expense (income) divided by the accounting profit. [Refer: Accounting profit]"
       }
      }
     },
     "auth_ref": [
      "r5",
      "r393"
     ]
    },
    "bbplc_AverageForeignExchangeRateOfHedgingInstrument": {
     "xbrltype": "decimalItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AverageForeignExchangeRateOfHedgingInstrument",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Average foreign exchange rate of hedging instrument",
        "label": "Average Foreign Exchange Rate Of Hedging Instrument",
        "documentation": "Average Foreign Exchange Rate Of Hedging Instrument"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AverageNumberOfEmployees": {
     "xbrltype": "decimalItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AverageNumberOfEmployees",
     "presentation": [
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Average number of employees (headcount)",
        "label": "Average number of employees"
       }
      },
      "en": {
       "role": {
        "documentation": "The average number of personnel employed by the entity during a period."
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "bbplc_AverageNumberOfEmployeesFullTimeEquivalent": {
     "xbrltype": "decimalItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "AverageNumberOfEmployeesFullTimeEquivalent",
     "presentation": [
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Average number of employees (full time equivalent)",
        "label": "Average Number Of Employees, Full Time Equivalent",
        "documentation": "Average Number Of Employees, Full Time Equivalent"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_AverageRateOfHedgingInstrument": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "AverageRateOfHedgingInstrument",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Average rate of hedging instrument",
        "label": "Average rate of hedging instrument"
       }
      },
      "en": {
       "role": {
        "documentation": "The average rate of a hedging instrument. [Refer: Hedging instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r255"
     ]
    },
    "ecd_AwardExrcPrice": {
     "xbrltype": "perShareItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AwardExrcPrice",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Award Exercise Price",
        "terseLabel": "Exercise Price"
       }
      }
     },
     "auth_ref": [
      "r808"
     ]
    },
    "ecd_AwardGrantDateFairValue": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AwardGrantDateFairValue",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Award Grant Date Fair Value",
        "terseLabel": "Fair Value as of Grant Date"
       }
      }
     },
     "auth_ref": [
      "r809"
     ]
    },
    "ecd_AwardTmgDiscLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AwardTmgDiscLineItems",
     "lang": {
      "en-us": {
       "role": {
        "label": "Award Timing Disclosures [Line Items]",
        "terseLabel": "Award Timing Disclosures"
       }
      }
     },
     "auth_ref": [
      "r804"
     ]
    },
    "ecd_AwardTmgHowMnpiCnsdrdTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AwardTmgHowMnpiCnsdrdTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Award Timing, How MNPI Considered [Text Block]",
        "terseLabel": "Award Timing, How MNPI Considered"
       }
      }
     },
     "auth_ref": [
      "r804"
     ]
    },
    "ecd_AwardTmgMethodTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AwardTmgMethodTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Award Timing Method [Text Block]",
        "terseLabel": "Award Timing Method"
       }
      }
     },
     "auth_ref": [
      "r804"
     ]
    },
    "ecd_AwardTmgMnpiCnsdrdFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AwardTmgMnpiCnsdrdFlag",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Award Timing MNPI Considered [Flag]",
        "terseLabel": "Award Timing MNPI Considered"
       }
      }
     },
     "auth_ref": [
      "r804"
     ]
    },
    "ecd_AwardTmgMnpiDiscTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AwardTmgMnpiDiscTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Award Timing MNPI Disclosure [Text Block]",
        "terseLabel": "Award Timing MNPI Disclosure"
       }
      }
     },
     "auth_ref": [
      "r804"
     ]
    },
    "ecd_AwardTmgPredtrmndFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AwardTmgPredtrmndFlag",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Award Timing Predetermined [Flag]",
        "terseLabel": "Award Timing Predetermined"
       }
      }
     },
     "auth_ref": [
      "r804"
     ]
    },
    "us-gaap_AwardTypeAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/us-gaap/2025",
     "localname": "AwardTypeAxis",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Award Type [Axis]",
        "terseLabel": "Award Type"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_AwardUndrlygSecuritiesAmt": {
     "xbrltype": "decimalItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AwardUndrlygSecuritiesAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Award Underlying Securities Amount",
        "terseLabel": "Underlying Securities"
       }
      }
     },
     "auth_ref": [
      "r807"
     ]
    },
    "ecd_AwardsCloseToMnpiDiscIndName": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AwardsCloseToMnpiDiscIndName",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Awards Close in Time to MNPI Disclosures, Individual Name",
        "terseLabel": "Name"
       }
      }
     },
     "auth_ref": [
      "r806"
     ]
    },
    "ecd_AwardsCloseToMnpiDiscTable": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AwardsCloseToMnpiDiscTable",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Awards Close in Time to MNPI Disclosures [Table]",
        "terseLabel": "Awards Close in Time to MNPI Disclosures"
       }
      }
     },
     "auth_ref": [
      "r805"
     ]
    },
    "ecd_AwardsCloseToMnpiDiscTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "AwardsCloseToMnpiDiscTableTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Awards Close in Time to MNPI Disclosures [Table Text Block]",
        "terseLabel": "Awards Close in Time to MNPI Disclosures, Table"
       }
      }
     },
     "auth_ref": [
      "r805"
     ]
    },
    "bbplc_BXMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BXMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "BX",
        "label": "BX [Member]",
        "documentation": "BX"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_BankAcceptanceAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "BankAcceptanceAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialAssets",
       "weight": 1.0,
       "order": 7.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash collateral and settlement balances",
        "label": "Bank acceptance assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of bank acceptances recognised as assets."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_BankAcceptanceAssetsClassifiedAsCashEquivalents": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BankAcceptanceAssetsClassifiedAsCashEquivalents",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashAndCashEquivalents",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash collateral balances with central banks with original maturity of three months or less",
        "label": "Bank Acceptance Assets, Classified As Cash Equivalents",
        "documentation": "A classification of cash equivalents cash collateral and settlement balances with banks with original maturity less than three months. [Refer: Cash equivalents]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BankAcceptanceAssetsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BankAcceptanceAssetsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash collateral and settlement balances",
        "label": "Bank Acceptance Assets [Member]",
        "documentation": "Bank Acceptance Assets"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BankAcceptanceAssetsPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BankAcceptanceAssetsPercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash collateral and settlement balance, percentage",
        "label": "Bank Acceptance Assets, Percentage",
        "documentation": "The amount of cash collateral and settlement balance assets, expressed as a percentage."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_BankAcceptanceLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "BankAcceptanceLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialLiabilities",
       "weight": 1.0,
       "order": 10.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash collateral and settlement balances",
        "label": "Bank acceptance liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of bank acceptances recognised as liabilities."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_BankRateMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BankRateMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Bank rate",
        "label": "Bank Rate [Member]",
        "documentation": "This member stands for bank rate."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BanksMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BanksMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Banks",
        "label": "Banks [member]",
        "documentation": "This member stands for the bank counterparty."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysAlzinInvestmentsS.aR.l.Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysAlzinInvestmentsS.aR.l.Member",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Alzin Investments S.\u00e0 r.l.",
        "label": "Barclays Alzin Investments S.\u00e0 r.l. [Member]",
        "documentation": "Barclays Alzin Investments S.\u00e0 r.l."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysBankDelawareMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysBankDelawareMember",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Bank Delaware",
        "label": "Barclays Bank Delaware [member]",
        "documentation": "This member stands for subsidiary Barclays Bank Delaware."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysBankIrelandPlcMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysBankIrelandPlcMember",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Bank Ireland PLC",
        "label": "Barclays Bank Ireland PLC [member]",
        "documentation": "This member stands for the Barclays Bank Ireland PLC, the German business largely comprising Barclaycard and Business Banking customers."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysBankPlcMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysBankPlcMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Bank PLC",
        "label": "Barclays Bank PLC [member]",
        "documentation": "This member stands for the Barclays Bank PLC subsidiary."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysBankSectionPlanMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysBankSectionPlanMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Bank Section",
        "label": "Barclays Bank Section Plan [Member]",
        "documentation": "Barclays Bank Section Plan"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysBankUkPlcMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysBankUkPlcMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Bank UK PLC",
        "label": "Barclays Bank UK PLC [member]",
        "documentation": "A direct subsidiary of ultimate parent, Barclays PLC."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysBordangInvestmentsS.aR.l.Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysBordangInvestmentsS.aR.l.Member",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Bordang Investments S.\u00e0 r.l.",
        "label": "Barclays Bordang Investments S.\u00e0 r.l. [Member]",
        "documentation": "Barclays Bordang Investments S.\u00e0 r.l."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysCapitalAsiaLimitedBCALMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysCapitalAsiaLimitedBCALMember",
     "presentation": [
      "http://www.home.barclays/role/AcquisitionandDisposalsofsubsidiariesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Capital Asia Limited (BCAL)",
        "label": "Barclays Capital Asia Limited (BCAL) [Member]",
        "documentation": "Barclays Capital Asia Limited (BCAL)"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysCapitalIncMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysCapitalIncMember",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Capital Inc.",
        "label": "Barclays Capital Inc [member]",
        "documentation": "This member stands for Barclays Capital Inc."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysCapitalSecuritiesLimitedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysCapitalSecuritiesLimitedMember",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Capital Securities Limited",
        "label": "Barclays Capital Securities Limited [member]",
        "documentation": "This member stands for Barclays Capital Securities Limited."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysExecutionServicesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysExecutionServicesMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Execution Services",
        "label": "Barclays Execution Services [member]",
        "documentation": "Barclays Services Limited, the Group services company set up to provide services to Barclays UK and Barclays International to deliver operational continuity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysInternationalHoldingsLimitedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysInternationalHoldingsLimitedMember",
     "presentation": [
      "http://www.home.barclays/role/AcquisitionandDisposalsofsubsidiariesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays International Holdings Limited",
        "label": "Barclays International Holdings Limited [Member]",
        "documentation": "Barclays International Holdings Limited"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysInvestmentBankMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysInvestmentBankMember",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Investment Bank",
        "label": "Barclays Investment Bank [Member]",
        "documentation": "Barclays Investment Bank"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysInvestmentSolutionsLimitedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysInvestmentSolutionsLimitedMember",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Investment Solutions Limited",
        "label": "Barclays Investment Solutions Limited [Member]",
        "documentation": "Barclays Investment Solutions Limited"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysPensionSavingsPlanMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysPensionSavingsPlanMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "BPSP",
        "label": "Barclays Pension Savings Plan [member]",
        "documentation": "This member stands for a new UK pension scheme, the BPSP, was established to satisfy Auto Enrolment legislation."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysPrivateBankAndWealthManagementMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysPrivateBankAndWealthManagementMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofgoodwillallocatedtobusinessoperationsaccordingtobusinesssegmentsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails",
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Private Bank and Wealth Management",
        "verboseLabel": "Barclays Private Bank and Wealth Management",
        "label": "Barclays Private Bank And Wealth Management [Member]",
        "documentation": "Barclays Private Bank And Wealth Management"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysSecuredFundingLMLimitedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysSecuredFundingLMLimitedMember",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Secured Funding (LM) Limited",
        "label": "Barclays Secured Funding (LM) Limited [Member]",
        "documentation": "Barclays Secured Funding (LM) Limited"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysSecuredNotesFinanceLLPMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysSecuredNotesFinanceLLPMember",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Secured Notes Finance LLP",
        "label": "Barclays Secured Notes Finance LLP [Member]",
        "documentation": "Barclays Secured Notes Finance LLP"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysSecuritiesJapanLimitedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysSecuritiesJapanLimitedMember",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Securities Japan Limited",
        "label": "Barclays Securities Japan Limited [member]",
        "documentation": "This member stands for Barclays Securities Japan Limited."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysUKCorporateBankMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysUKCorporateBankMember",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails",
      "http://www.home.barclays/role/SegmentalreportingNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays UK Corporate Bank",
        "label": "Barclays UK Corporate Bank [Member]",
        "documentation": "Barclays UK Corporate Bank"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysUSConsumerBankMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysUSConsumerBankMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofgoodwillallocatedtobusinessoperationsaccordingtobusinesssegmentsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails",
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays US Consumer Bank",
        "label": "Barclays US Consumer Bank [Member]",
        "documentation": "Barclays US Consumer Bank"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysUkMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysUkMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "UK Banking Business",
        "label": "Barclays UK [member]",
        "documentation": "Barclays UK comprises our UK Personal Banking, UK Business Banking and Barclaycard Consumer UK businesses. These businesses are carried on by our UK ring-fenced bank (Barclays Bank UK PLC) and certain other entities within the Group."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BarclaysUsLlcMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BarclaysUsLlcMember",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays US LLC",
        "label": "Barclays US LLC [member]",
        "documentation": "The intermediate holding company established by Barclays in July 2016, which holds most of Barclays' subsidiaries and assets in the US."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BaselineMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BaselineMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Baseline",
        "label": "Baseline [member]",
        "documentation": "An external consensus forecast is assembled from key sources, including HM Treasury, Bloomberg and the Urban Land Institute."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BasisRiskMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BasisRiskMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Basis risk",
        "label": "Basis Risk [Member]",
        "documentation": "This member stands for the basis risk factor."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BdcFinanceLlcMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BdcFinanceLlcMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "BDC Finance LLC",
        "label": "BDC Finance LLC [Member]",
        "documentation": "BDC Finance L.L.C. (BDC) has filed a complaint against Barclays Bank PLC alleging breach of contract in connection with a portfolio of total return swaps governed by an ISDA Master Agreement (collectively, the Agreement)."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BondsCorporateAndOtherMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BondsCorporateAndOtherMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Bonds - corporate and other",
        "label": "Bonds - Corporate And Other [Member]",
        "documentation": "This member stands for Bonds - corporate and other debt instrument."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BondsFixedGovernmentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BondsFixedGovernmentMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Bonds - fixed government",
        "label": "Bonds Fixed Government [Member]",
        "documentation": "This member stands for Bonds - fixed government debt instrument."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BondsIndexLinkedGovernmentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BondsIndexLinkedGovernmentMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Bonds - index-linked government",
        "label": "Bonds Index Linked Government [Member]",
        "documentation": "This member stands for Bonds - index linked government debt instruments."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_BorrowingsByNameAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "BorrowingsByNameAxis",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Borrowings by name [axis]",
        "label": "Borrowings by name [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r875"
     ]
    },
    "ifrs-full_BorrowingsByNameDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "BorrowingsByNameDomain",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Borrowings by name [domain]",
        "label": "Borrowings by name [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all borrowings when disaggregated by name. It also represents the standard value for the 'Borrowings by name' axis if no other member is used. [Refer: Borrowings]"
       }
      }
     },
     "auth_ref": [
      "r875"
     ]
    },
    "bbplc_BorrowingsConversionRatioThresholdPercent": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BorrowingsConversionRatioThresholdPercent",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Conversion ratio threshold, percent",
        "label": "Borrowings, Conversion Ratio Threshold, Percent",
        "documentation": "Borrowings, Conversion Ratio Threshold, Percent"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_BorrowingsInterestRate": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "BorrowingsInterestRate",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Interest rate",
        "label": "Borrowings, interest rate"
       }
      },
      "en": {
       "role": {
        "documentation": "The interest rate on borrowings. [Refer: Borrowings]"
       }
      }
     },
     "auth_ref": [
      "r875"
     ]
    },
    "bbplc_BorrowingsWhichHedgeNetInvestmentsHedges": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BorrowingsWhichHedgeNetInvestmentsHedges",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails": {
       "parentTag": "bbplc_StructuralCurrencyExposureBeforeHedgingInstruments",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Borrowings which hedge the net investments",
        "label": "Borrowings Which Hedge Net Investments, Hedges",
        "documentation": "The amount of hedges classified as borrowings which hedge the net investments."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_BottomOfRangeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "BottomOfRangeMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsNarrativeDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails",
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Low",
        "verboseLabel": "Bottom of range",
        "netLabel": "Min",
        "label": "Bottom of range [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the bottom of a range."
       }
      }
     },
     "auth_ref": [
      "r127",
      "r177",
      "r202",
      "r222",
      "r386",
      "r649",
      "r651",
      "r875"
     ]
    },
    "bbplc_BrokerageCommissionsAndClientExecutionFeesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BrokerageCommissionsAndClientExecutionFeesMember",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Brokerage and execution",
        "label": "Brokerage Commissions And Client Execution Fees [Member]",
        "documentation": "This member stands for fees earned for executing client transactions with exchanges and over-the- counter markets and assisting clients in clearing transactions."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_BrokeredCertificatesOfDepositMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BrokeredCertificatesOfDepositMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Brokered certificates of deposit",
        "label": "Brokered Certificates Of Deposit [Member]",
        "documentation": "This member stands for structured and brokered certificates of deposit issued by the entity are insured up to $250,000 per depositor by the Federal Deposit Insurance Corporation (FDIC) in the US."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_BuildingsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "BuildingsMember",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Freehold buildings",
        "label": "Buildings [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a class of plant, property and equipment representing depreciable buildings and similar structures for use in operations. [Refer: Property, plant and equipment]"
       }
      }
     },
     "auth_ref": [
      "r838"
     ]
    },
    "bbplc_BusinessAndOtherServicesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "BusinessAndOtherServicesMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Business and other services",
        "label": "Business And Other Services [Member]",
        "documentation": "This member stands for the business and other services industry."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_BusinessCombinationsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "BusinessCombinationsAxis",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Business combinations [axis]",
        "label": "Business combinations [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r228",
      "r472"
     ]
    },
    "ifrs-full_BusinessCombinationsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "BusinessCombinationsDomain",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Business combinations [domain]",
        "label": "Business combinations [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the standard value for the 'Business combinations' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r228",
      "r231",
      "r472"
     ]
    },
    "dei_BusinessContactMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "BusinessContactMember",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Business Contact",
        "label": "Business Contact [Member]",
        "documentation": "Business contact for the entity"
       }
      }
     },
     "auth_ref": [
      "r727",
      "r750"
     ]
    },
    "currency_CAD": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/currency/2025",
     "localname": "CAD",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "CAD",
        "label": "Canada, Dollars"
       }
      }
     },
     "auth_ref": []
    },
    "currency_CHF": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/currency/2025",
     "localname": "CHF",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "CHF",
        "label": "Switzerland, Francs"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CalledUpShareCapitalAndSharePremium": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CalledUpShareCapitalAndSharePremium",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Equity",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Called up share capital and share premium",
        "label": "Called Up Share Capital And Share Premium",
        "documentation": "The amount of equity interest of an entity without share capital that the entity does not separately disclose in the same statement or note."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CapitalLossesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CapitalLossesMember",
     "presentation": [
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Capital losses",
        "label": "Capital Losses [Member]",
        "documentation": "This member stands for capital losses that have been received and are carried forward for use against future taxable profit."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CapitalRequirementsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CapitalRequirementsAxis",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcapitalresourcesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Capital requirements [axis]",
        "label": "Capital requirements [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r561"
     ]
    },
    "ifrs-full_CapitalRequirementsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CapitalRequirementsDomain",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcapitalresourcesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Capital requirements [domain]",
        "label": "Capital requirements [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for capital requirements that the entity is subject to. It also represents the standard value for the 'Capital requirements' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r561"
     ]
    },
    "ifrs-full_CapitalisationRateMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CapitalisationRateMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Allocated capital rate",
        "label": "Capitalisation rate, measurement input [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a capitalisation rate used as a measurement input."
       }
      }
     },
     "auth_ref": [
      "r639",
      "r651"
     ]
    },
    "bbplc_CardsUnsecuredLoansAndOtherPersonalLendingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CardsUnsecuredLoansAndOtherPersonalLendingMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cards, unsecured loans and other personal lending",
        "label": "Cards, Unsecured Loans And Other Personal Lending [Member]",
        "documentation": "This member stands for the cards, unsecured loans and other personal lending industry."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails",
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Carrying amount, accumulated depreciation, amortisation and impairment and gross carrying amount [axis]",
        "label": "Carrying amount, accumulated depreciation, amortisation and impairment and gross carrying amount [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r14",
      "r15",
      "r101",
      "r103",
      "r112",
      "r113",
      "r114",
      "r115",
      "r116",
      "r230",
      "r285",
      "r286",
      "r400",
      "r401",
      "r450",
      "r452",
      "r454",
      "r455",
      "r456",
      "r457",
      "r458",
      "r473",
      "r511",
      "r513"
     ]
    },
    "ifrs-full_CarryingAmountMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CarryingAmountMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails",
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Carrying amount [member]",
        "label": "Carrying amount [member]"
       }
      }
     },
     "auth_ref": [
      "r15",
      "r103",
      "r112",
      "r114",
      "r115",
      "r230",
      "r285",
      "r286",
      "r401",
      "r452",
      "r454",
      "r456",
      "r457",
      "r473",
      "r511",
      "r513"
     ]
    },
    "bbplc_Cash1Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "Cash1Member",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash",
        "label": "Cash1 [Member]",
        "documentation": "Cash1"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CashAndBankBalancesAtCentralBanks": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashAndBankBalancesAtCentralBanks",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashAndCashEquivalents",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialAssets",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash and balances at central banks",
        "label": "Cash and bank balances at central banks"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of cash and bank balances held at central banks."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_CashAndBankBalancesAtCentralBanksMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CashAndBankBalancesAtCentralBanksMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash and balances at central banks",
        "label": "Cash And Bank Balances At Central Banks [Member]",
        "documentation": "This member stands for cash and bank balances held at central banks."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CashAndBankBalancesAtCentralBanksPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CashAndBankBalancesAtCentralBanksPercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash and balances at central banks, percentage",
        "label": "Cash And Bank Balances At Central Banks, Percentage",
        "documentation": "The amount of cash and bank balances held at central banks, expressed as a percentage."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CashAndCashEquivalents": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashAndCashEquivalents",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "periodStartLabel": "Cash and cash equivalents at beginning of year",
        "periodEndLabel": "Cash and cash equivalents at end of year",
        "totalLabel": "Cash and cash equivalents at end of year",
        "label": "Cash and cash equivalents"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of cash on hand and demand deposits, along with short-term, highly liquid investments that are readily convertible to known amounts of cash and that are subject to an insignificant risk of changes in value. [Refer: Cash; Cash equivalents]"
       }
      }
     },
     "auth_ref": [
      "r128",
      "r149",
      "r387",
      "r569"
     ]
    },
    "bbplc_CashAndCashEquivalents1Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CashAndCashEquivalents1Member",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash And Cash Equivalents1",
        "label": "Cash And Cash Equivalents1 [Member]",
        "documentation": "This member stands for the cash and cash equivalents."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CashAndCashEquivalentsAmountContributedToFairValueOfPlanAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashAndCashEquivalentsAmountContributedToFairValueOfPlanAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails": {
       "parentTag": "ifrs-full_PlanAssetsAtFairValue",
       "weight": 1.0,
       "order": 8.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash and liquid assets",
        "label": "Cash and cash equivalents, amount contributed to fair value of plan assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount cash and cash equivalents contribute to the fair value of defined benefit plan assets. [Refer: Cash and cash equivalents; Plan assets, at fair value; Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r613"
     ]
    },
    "bbplc_CashAndCashEquivalentsCompriseAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CashAndCashEquivalentsCompriseAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash and cash equivalents comprise:",
        "label": "Cash And Cash Equivalents Comprise: [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CashAndCashEquivalentsNettingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CashAndCashEquivalentsNettingMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash and liquid assets",
        "label": "Cash And Cash Equivalents, Netting [Member]",
        "documentation": "This member stands for the cash and cash equivalents."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CashCollateralAndSettlementBalanceLiabilitiesUndiscounted": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CashCollateralAndSettlementBalanceLiabilitiesUndiscounted",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails": {
       "parentTag": "bbplc_TotalFinancialLiabilitiesUndiscounted",
       "weight": 1.0,
       "order": 8.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash collateral and settlement balances, undiscounted",
        "label": "Cash Collateral And Settlement Balance Liabilities, Undiscounted",
        "documentation": "The amount of contractual undiscounted cash flows in relation to cash collateral and settlement balance liabilities."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CashCollateralAndSettlementsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CashCollateralAndSettlementsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash collateral and settlements",
        "label": "Cash Collateral And Settlements [Member]",
        "documentation": "Cash Collateral And Settlements"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CashCollateralNettedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CashCollateralNettedMember",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash collateral netted",
        "label": "Cash Collateral Netted [Member]",
        "documentation": "This member stands for cash collateral netted."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CashCollateralPledgedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashCollateralPledgedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash collateral pledged",
        "label": "Cash collateral pledged subject to enforceable master netting arrangement or similar agreement not set off against financial liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of cash collateral pledged that is subject to an enforceable master netting arrangement or similar agreement and that is not set off against financial liabilities. [Refer: Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r659",
      "r692"
     ]
    },
    "ifrs-full_CashCollateralReceivedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashCollateralReceivedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssets",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails": {
       "parentTag": "bbplc_NetExposureToCreditRisk",
       "weight": -1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Cash collateral",
        "terseLabel": "Cash collateral",
        "label": "Cash collateral received subject to enforceable master netting arrangement or similar agreement not set off against financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of cash collateral received that is subject to an enforceable master netting arrangement or similar agreement and that is not set off against financial assets. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r659",
      "r692"
     ]
    },
    "ifrs-full_CashFlowHedgesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashFlowHedgesAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash flow hedging reserve",
        "label": "Cash flow hedges [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CashFlowHedgesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashFlowHedgesMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash flow hedges",
        "verboseLabel": "Cash flow",
        "label": "Cash flow hedges [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for hedges of the exposure to variability in cash flows that (a) are attributable to a particular risk associated with a recognised asset or liability (such as all or some future interest payments on variable rate debt) or a highly probable forecast transaction; and (b) could affect profit or loss. [Refer: Types of hedges [domain]]"
       }
      }
     },
     "auth_ref": [
      "r109",
      "r259",
      "r267",
      "r271",
      "r494",
      "r499",
      "r503"
     ]
    },
    "ifrs-full_CashFlowsFromLosingControlOfSubsidiariesOrOtherBusinessesClassifiedAsInvestingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashFlowsFromLosingControlOfSubsidiariesOrOtherBusinessesClassifiedAsInvestingActivities",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": 1.0,
       "order": 6.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disposal/(Acquisition) of subsidiaries and associates, net of cash disposed",
        "label": "Cash flows from losing control of subsidiaries or other businesses, classified as investing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The aggregate cash flows arising from losing control of subsidiaries or other businesses, classified as investing activities. [Refer: Total for all subsidiaries [member]]"
       }
      }
     },
     "auth_ref": [
      "r123"
     ]
    },
    "ifrs-full_CashFlowsFromUsedInFinancingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashFlowsFromUsedInFinancingActivities",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_IncreaseDecreaseInCashAndCashEquivalents",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Net cash from financing activities",
        "label": "Cash flows from (used in) financing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash flows from (used in) financing activities, which are activities that result in changes in the size and composition of the contributed equity and borrowings of the entity, from continuing and discontinued operations."
       }
      }
     },
     "auth_ref": [
      "r117",
      "r129"
     ]
    },
    "ifrs-full_CashFlowsFromUsedInFinancingActivitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashFlowsFromUsedInFinancingActivitiesAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash flows from (used in) financing activities",
        "label": "Cash flows from (used in) financing activities [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CashFlowsFromUsedInInvestingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashFlowsFromUsedInInvestingActivities",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_IncreaseDecreaseInCashAndCashEquivalents",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Net cash from investing activities",
        "label": "Cash flows from (used in) investing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash flows from (used in) investing activities, which are the acquisition and disposal of long-term assets and other investments not included in cash equivalents, from continuing and discontinued operations."
       }
      }
     },
     "auth_ref": [
      "r117",
      "r129"
     ]
    },
    "ifrs-full_CashFlowsFromUsedInInvestingActivitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashFlowsFromUsedInInvestingActivitiesAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash flows from (used in) investing activities",
        "label": "Cash flows from (used in) investing activities [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CashFlowsFromUsedInOperatingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashFlowsFromUsedInOperatingActivities",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_IncreaseDecreaseInCashAndCashEquivalents",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Net cash from operating activities",
        "label": "Cash flows from (used in) operating activities"
       }
      }
     },
     "auth_ref": [
      "r117",
      "r129"
     ]
    },
    "ifrs-full_CashFlowsFromUsedInOperatingActivitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashFlowsFromUsedInOperatingActivitiesAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash flows from (used in) operating activities",
        "label": "Cash flows from (used in) operating activities [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CashFlowsUsedInObtainingControlOfSubsidiariesOrOtherBusinessesClassifiedAsInvestingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashFlowsUsedInObtainingControlOfSubsidiariesOrOtherBusinessesClassifiedAsInvestingActivities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": -1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": -1.0,
       "order": 7.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Acquisition of business",
        "negatedTerseLabel": "Net increase in investment in subsidiaries",
        "label": "Cash flows used in obtaining control of subsidiaries or other businesses, classified as investing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The aggregate cash flows used in obtaining control of subsidiaries or other businesses, classified as investing activities. [Refer: Total for all subsidiaries [member]]"
       }
      }
     },
     "auth_ref": [
      "r123"
     ]
    },
    "ifrs-full_CashOutflowForLeases": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashOutflowForLeases",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofleaseliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Cash payments",
        "label": "Cash outflow for leases"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash outflow for leases."
       }
      }
     },
     "auth_ref": [
      "r192",
      "r365"
     ]
    },
    "ifrs-full_CashReceiptsFromRepaymentOfAdvancesAndLoansMadeToRelatedParties": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CashReceiptsFromRepaymentOfAdvancesAndLoansMadeToRelatedParties",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans issued during the year",
        "label": "Cash receipts from repayment of advances and loans made to related parties"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash inflow from repayment to the entity of loans and advances made to related parties. [Refer: Total for all related parties [member]]"
       }
      }
     },
     "auth_ref": [
      "r863"
     ]
    },
    "ifrs-full_CategoriesOfFinancialAssetsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CategoriesOfFinancialAssetsAbstract",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets",
        "label": "Categories of financial assets [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CategoriesOfFinancialAssetsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CategoriesOfFinancialAssetsAxis",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcarryingamountoftheassetspledgedassecurityagainstliabilitiesDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughothercomprehensiveincomeDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails",
      "http://www.home.barclays/role/NettradingincomeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails",
      "http://www.home.barclays/role/SecuritisationsNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Categories of financial assets [axis]",
        "label": "Categories of financial assets [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r319",
      "r481"
     ]
    },
    "ifrs-full_CategoriesOfFinancialAssetsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CategoriesOfFinancialAssetsDomain",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcarryingamountoftheassetspledgedassecurityagainstliabilitiesDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughothercomprehensiveincomeDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails",
      "http://www.home.barclays/role/NettradingincomeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails",
      "http://www.home.barclays/role/SecuritisationsNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Categories of financial assets [domain]",
        "label": "Categories of financial assets [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for aggregated categories of financial assets. It also represents the standard value for the 'Categories of financial assets' axis if no other member is used. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r319",
      "r481"
     ]
    },
    "ifrs-full_CategoriesOfFinancialLiabilitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CategoriesOfFinancialLiabilitiesAbstract",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial liabilities",
        "label": "Categories of financial liabilities [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CategoriesOfFinancialLiabilitiesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CategoriesOfFinancialLiabilitiesAxis",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/NettradingincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Categories of financial liabilities [axis]",
        "label": "Categories of financial liabilities [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r319",
      "r481"
     ]
    },
    "ifrs-full_CategoriesOfFinancialLiabilitiesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CategoriesOfFinancialLiabilitiesDomain",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/NettradingincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Categories of financial liabilities",
        "label": "Categories of financial liabilities [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for aggregated categories of financial liabilities. It also represents the standard value for the 'Categories of financial liabilities' axis if no other member is used. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r319",
      "r481"
     ]
    },
    "ifrs-full_CategoriesOfRelatedPartiesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CategoriesOfRelatedPartiesAxis",
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails",
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofamountsincludedintheGroupsfinancialstatementsbycategoryDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofloansanddepositsoutstandingDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Categories of related parties [axis]",
        "label": "Categories of related parties [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r58",
      "r428"
     ]
    },
    "ifrs-full_CategoriesOfRelatedPartiesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CategoriesOfRelatedPartiesDomain",
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails",
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofamountsincludedintheGroupsfinancialstatementsbycategoryDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofloansanddepositsoutstandingDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Categories of related parties [domain]",
        "label": "Categories of related parties [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the standard value for the 'Categories of related parties' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r58",
      "r428"
     ]
    },
    "bbplc_CertainCoreBankingPlatformsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CertainCoreBankingPlatformsMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Certain core banking platforms",
        "label": "Certain Core Banking Platforms [Member]",
        "documentation": "This member stands for certain core banking platforms, internally developed by the entity."
       }
      }
     },
     "auth_ref": []
    },
    "ecd_ChangedPeerGroupFnTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "ChangedPeerGroupFnTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Changed Peer Group, Footnote [Text Block]",
        "terseLabel": "Changed Peer Group, Footnote"
       }
      }
     },
     "auth_ref": [
      "r783"
     ]
    },
    "ifrs-full_ChangesInEquityAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ChangesInEquityAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Changes in equity [abstract]",
        "label": "Changes in equity [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ChangesInFairValueOfFinancialAssetsAttributableToChangesInCreditRiskOfFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ChangesInFairValueOfFinancialAssetsAttributableToChangesInCreditRiskOfFinancialAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Changes in fair value during the year ended",
        "label": "Increase (decrease) in fair value of financial assets designated as measured at fair value through profit or loss, attributable to changes in credit risk of financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in the fair value of a financial asset (or group of financial assets) designated as measured at fair value through profit or loss that is attributable to changes in the credit risk of that asset determined either: (a) as the amount of change in its fair value that is not attributable to changes in market conditions that give rise to market risk ; or (b) using an alternative method the entity believes more faithfully represents the amount of change in its fair value that is attributable to changes in the credit risk of the asset. [Refer: Credit risk [member]; Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r321"
     ]
    },
    "bbplc_ChangesInOperatingAssetsAndLiabilitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ChangesInOperatingAssetsAndLiabilitiesAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Changes in operating assets and liabilities",
        "label": "Changes In Operating Assets And Liabilities [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ChangesInOtherProvisions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ChangesInOtherProvisions",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net change in expected credit loss provision and other movements",
        "label": "Increase (decrease) in other provisions"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in other provisions. [Refer: Other provisions]"
       }
      }
     },
     "auth_ref": [
      "r95",
      "r445"
     ]
    },
    "ifrs-full_ChangesInPropertyPlantAndEquipment": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ChangesInPropertyPlantAndEquipment",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails": {
       "parentTag": "bbplc_InfrastructureCosts",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Property and equipment",
        "label": "Increase (decrease) in property, plant and equipment"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in property, plant and equipment. [Refer: Property, plant and equipment]"
       }
      }
     },
     "auth_ref": [
      "r15",
      "r401"
     ]
    },
    "ifrs-full_CharacteristicsOfDefinedBenefitPlansAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CharacteristicsOfDefinedBenefitPlansAxis",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Characteristics of defined benefit plans [axis]",
        "label": "Characteristics of defined benefit plans [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r611"
     ]
    },
    "ifrs-full_CharacteristicsOfDefinedBenefitPlansDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CharacteristicsOfDefinedBenefitPlansDomain",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Characteristics of defined benefit plans [domain]",
        "label": "Characteristics of defined benefit plans [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all defined benefit plans when disaggregated by characteristics of defined benefits plans. It also represents the standard value for the 'Characteristics of defined benefit plans' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r611"
     ]
    },
    "ecd_ChngInFrValAsOfVstngDtOfPrrYrEqtyAwrdsVstdInCvrdYrMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "ChngInFrValAsOfVstngDtOfPrrYrEqtyAwrdsVstdInCvrdYrMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member]",
        "terseLabel": "Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year"
       }
      }
     },
     "auth_ref": [
      "r780"
     ]
    },
    "ecd_ChngInFrValOfOutsdngAndUnvstdEqtyAwrdsGrntdInPrrYrsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "ChngInFrValOfOutsdngAndUnvstdEqtyAwrdsGrntdInPrrYrsMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member]",
        "terseLabel": "Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested"
       }
      }
     },
     "auth_ref": [
      "r778"
     ]
    },
    "dei_CityAreaCode": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "CityAreaCode",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "City Area Code",
        "label": "City Area Code",
        "documentation": "Area code of city"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CivilActionsInRespectOfTheUSAntiTerrorismActEDNYMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CivilActionsInRespectOfTheUSAntiTerrorismActEDNYMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Civil actions in respect of the US Anti-Terrorism Act - EDNY",
        "label": "Civil Actions In Respect Of The US Anti-Terrorism Act - EDNY [Member]",
        "documentation": "Civil complaints against Barclays Bank PLC and other banks allege engagement in a conspiracy and violation of the US Anti-Terrorism Act (ATA)."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CivilActionsInRespectOfTheUSAntiTerrorismActMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CivilActionsInRespectOfTheUSAntiTerrorismActMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Civil actions in respect of the US Anti-Terrorism Act",
        "label": "Civil Actions In Respect Of The US Anti-Terrorism Act [Member]",
        "documentation": "Civil complaints against Barclays Bank PLC and other banks allege engagement in a conspiracy and violation of the US Anti-Terrorism Act (ATA)."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CivilActionsInRespectOfTheUSAntiTerrorismActSDNYMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CivilActionsInRespectOfTheUSAntiTerrorismActSDNYMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Civil actions in respect of the US Anti-Terrorism Act - SDNY",
        "label": "Civil Actions In Respect Of The US Anti-Terrorism Act - SDNY [Member]",
        "documentation": "Civil Actions In Respect Of The US Anti-Terrorism Act - SDNY"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CivilActionsInRespectOfVRDOPrivatePlaintiffsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CivilActionsInRespectOfVRDOPrivatePlaintiffsMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Civil actions in respect of VRDO - private plaintiffs",
        "label": "Civil Actions In Respect Of VRDO - Private Plaintiffs [Member]",
        "documentation": "Civil Actions In Respect Of VRDO - Private Plaintiffs"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ClassesOfAssetsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfAssetsAxis",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughothercomprehensiveincomeDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of assets [axis]",
        "label": "Classes of assets [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r72",
      "r75",
      "r173",
      "r193",
      "r366",
      "r434",
      "r534"
     ]
    },
    "ifrs-full_ClassesOfAssetsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfAssetsDomain",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughothercomprehensiveincomeDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of assets [domain]",
        "label": "Classes of assets [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a present economic resource controlled by the entity as a result of past events. Economic resource is a right that has the potential to produce economic benefits. It also represents the standard value for the 'Classes of assets' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r72",
      "r173",
      "r193",
      "r366",
      "r434",
      "r534"
     ]
    },
    "ifrs-full_ClassesOfContingentLiabilitiesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfContingentLiabilitiesAxis",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails",
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of contingent liabilities [axis]",
        "label": "Classes of contingent liabilities [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r98",
      "r229",
      "r448"
     ]
    },
    "ifrs-full_ClassesOfContingentLiabilitiesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfContingentLiabilitiesDomain",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails",
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of contingent liabilities [domain]",
        "label": "Classes of contingent liabilities [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for possible obligations that arise from past events and whose existence will be confirmed only by the occurrence or non-occurrence of one or more uncertain future events not wholly within the control of the entity; or, present obligations that arise from past events but are not recognised because (a) it is probable that an outflow of resources embodying economic benefits will be required to settle the obligations; or (b) the amount of the obligations cannot be measured with sufficient reliability. It also represents the standard value for the 'Classes of contingent liabilities' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r99",
      "r229"
     ]
    },
    "ifrs-full_ClassesOfEmployeeBenefitsExpenseAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfEmployeeBenefitsExpenseAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of employee benefits expense [abstract]",
        "label": "Classes of employee benefits expense [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ClassesOfFinancialAssetsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfFinancialAssetsAxis",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails",
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of financial assets [axis]",
        "label": "Classes of financial assets [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r211",
      "r312",
      "r313",
      "r351",
      "r352",
      "r548"
     ]
    },
    "ifrs-full_ClassesOfFinancialAssetsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfFinancialAssetsDomain",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails",
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of financial assets [domain]",
        "label": "Classes of financial assets [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for aggregated classes of financial assets. It also represents the standard value for the 'Classes of financial assets' axis if no other member is used. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r211",
      "r312",
      "r313",
      "r351",
      "r352",
      "r548"
     ]
    },
    "ifrs-full_ClassesOfFinancialInstrumentsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfFinancialInstrumentsAxis",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredNarrativeDetails",
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails",
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/TradingportfolioDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of financial instruments [axis]",
        "label": "Classes of financial instruments [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r285",
      "r291",
      "r296",
      "r297",
      "r511",
      "r517"
     ]
    },
    "ifrs-full_ClassesOfFinancialInstrumentsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfFinancialInstrumentsDomain",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredNarrativeDetails",
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails",
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/TradingportfolioDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of financial instruments [domain]",
        "label": "Classes of financial instruments [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for aggregated classes of financial instruments. Financial instruments are contracts that give rise to a financial asset of one entity and a financial liability or equity instrument of another entity. It also represents the standard value for the 'Classes of financial instruments' axis if no other member is used. [Refer: Financial assets; Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r285",
      "r291",
      "r296",
      "r297",
      "r511",
      "r517"
     ]
    },
    "ifrs-full_ClassesOfFinancialLiabilitiesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfFinancialLiabilitiesAxis",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of financial liabilities [axis]",
        "label": "Classes of financial liabilities [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r312",
      "r313",
      "r351",
      "r352"
     ]
    },
    "ifrs-full_ClassesOfFinancialLiabilitiesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfFinancialLiabilitiesDomain",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of financial liabilities [domain]",
        "label": "Classes of financial liabilities [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for aggregated classes financial liabilities. It also represents the standard value for the 'Classes of financial liabilities' axis if no other member is used. [Refer: Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r312",
      "r313",
      "r351",
      "r352"
     ]
    },
    "ifrs-full_ClassesOfIntangibleAssetsAndGoodwillAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfIntangibleAssetsAndGoodwillAxis",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of intangible assets and goodwill [axis]",
        "label": "Classes of intangible assets and goodwill [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r858"
     ]
    },
    "ifrs-full_ClassesOfIntangibleAssetsAndGoodwillDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfIntangibleAssetsAndGoodwillDomain",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of intangible assets and goodwill [domain]",
        "label": "Classes of intangible assets and goodwill [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for intangible assets and goodwill. It also represents the standard value for the 'Classes of intangible assets and goodwill' axis if no other member is used. [Refer: Goodwill; Intangible assets other than goodwill]"
       }
      }
     },
     "auth_ref": [
      "r858"
     ]
    },
    "ifrs-full_ClassesOfLiabilitiesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfLiabilitiesAxis",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of liabilities [axis]",
        "label": "Classes of liabilities [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r173",
      "r534"
     ]
    },
    "ifrs-full_ClassesOfLiabilitiesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfLiabilitiesDomain",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of liabilities [domain]",
        "label": "Classes of liabilities [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a present obligation of the entity to transfer an economic resource as a result of past events. Economic resource is a right that has the potential to produce economic benefits. It also represents the standard value for the 'Classes of liabilities' axis if no other member is used. [Refer: Liabilities]"
       }
      }
     },
     "auth_ref": [
      "r173",
      "r534"
     ]
    },
    "ifrs-full_ClassesOfOtherProvisionsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfOtherProvisionsDomain",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsNarrativeDetails",
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails",
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails",
      "http://www.home.barclays/role/ProvisionsNarrativeDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of other provisions [domain]",
        "label": "Classes of other provisions [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for provisions other than provisions for employee benefits. It also represents the standard value for the 'Classes of other provisions' axis if no other member is used. [Refer: Provisions]"
       }
      }
     },
     "auth_ref": [
      "r95",
      "r445"
     ]
    },
    "ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfPropertyPlantAndEquipmentAxis",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentNarrativeDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of property, plant and equipment [axis]",
        "label": "Classes of property, plant and equipment [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r16",
      "r402"
     ]
    },
    "ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfPropertyPlantAndEquipmentDomain",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentNarrativeDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of property, plant and equipment [domain]",
        "label": "Classes of property, plant and equipment [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the standard value for the 'Classes of property, plant and equipment' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r16",
      "r402"
     ]
    },
    "ifrs-full_ClassesOfProvisionsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfProvisionsAxis",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsNarrativeDetails",
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails",
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails",
      "http://www.home.barclays/role/ProvisionsNarrativeDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of other provisions [axis]",
        "label": "Classes of other provisions [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r95",
      "r445"
     ]
    },
    "ifrs-full_ClassesOfShareCapitalAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfShareCapitalAxis",
     "presentation": [
      "http://www.home.barclays/role/Cover",
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of share capital [axis]",
        "label": "Classes of share capital [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r380",
      "r537",
      "r584"
     ]
    },
    "ifrs-full_ClassesOfShareCapitalDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ClassesOfShareCapitalDomain",
     "presentation": [
      "http://www.home.barclays/role/Cover",
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Classes of share capital [domain]",
        "label": "Classes of share capital [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for share capital of the entity. It also represents the standard value for the 'Classes of share capital' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r380",
      "r537",
      "r584"
     ]
    },
    "bbplc_ClearedByCentralCounterpartyMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ClearedByCentralCounterpartyMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Derivatives cleared by central counterparty",
        "label": "Cleared By Central Counterparty [Member]",
        "documentation": "This member stands for derivatives cleared by central counterparty."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CoBrandedCardPortfolioMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CoBrandedCardPortfolioMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Co-branded card portfolio",
        "label": "Co-Branded Card Portfolio [Member]",
        "documentation": "Co-Branded Card Portfolio"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_CoSelectedMeasureAmt": {
     "xbrltype": "decimalItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "CoSelectedMeasureAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Company Selected Measure Amount",
        "terseLabel": "Company Selected Measure Amount"
       }
      }
     },
     "auth_ref": [
      "r784"
     ]
    },
    "ecd_CoSelectedMeasureName": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "CoSelectedMeasureName",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Company Selected Measure Name",
        "terseLabel": "Company Selected Measure Name"
       }
      }
     },
     "auth_ref": [
      "r784"
     ]
    },
    "bbplc_CommercialMortgageBackedSecurityMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CommercialMortgageBackedSecurityMember",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureofcontinuinginvolvementinfinancialassetsthathavebeenderecognisedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Commercial mortgage backed securities",
        "label": "Commercial Mortgage Backed Security [Member]",
        "documentation": "This member stands for commerical mortgage backed securities held by the entity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CommercialPaperCPAndMediumTermNoteConduitsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CommercialPaperCPAndMediumTermNoteConduitsMember",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "CP's and medium-term note conduits",
        "label": "Commercial Paper (CP) And Medium-Term Note Conduits [Member]",
        "documentation": "This member stands for commercial paper and medium term loan conduits."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CommitmentsAndFinancialGuaranteeContractsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CommitmentsAndFinancialGuaranteeContractsMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Off-balance sheet loan commitments and financial guarantee contracts",
        "label": "Commitments And Financial Guarantee Contracts [Member]",
        "documentation": "Commitments And Financial Guarantee Contracts"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CommitmentsGiven": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CommitmentsGiven",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total off-balance sheet commitments given",
        "label": "Commitments Given",
        "documentation": "The amount of commitments given, including contingent liabilities, documentary credits and other short-term trade related transactions, and standby facilities, credit lines and other commitments."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CommitmentsMadeByEntityRelatedPartyTransactions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CommitmentsMadeByEntityRelatedPartyTransactions",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Commitments made by entity, related party transactions",
        "label": "Commitments made by entity, related party transactions"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of related-party commitments made by the entity to do something if a particular event occurs or does not occur in the future, including executory contracts (recognised and unrecognised). [Refer: Total for all related parties [member]]"
       }
      }
     },
     "auth_ref": [
      "r620"
     ]
    },
    "ifrs-full_CommitmentsMadeOnBehalfOfEntityRelatedPartyTransactions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CommitmentsMadeOnBehalfOfEntityRelatedPartyTransactions",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total value of guarantees entered into on behalf of Directors",
        "label": "Commitments made on behalf of entity, related party transactions"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of related-party commitments made on behalf of the entity to do something if a particular event occurs or does not occur in the future, including executory contracts (recognised and unrecognised). [Refer: Total for all related parties [member]]"
       }
      }
     },
     "auth_ref": [
      "r620"
     ]
    },
    "bbplc_CommoditiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CommoditiesMember",
     "presentation": [
      "http://www.home.barclays/role/TradingportfolioDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Commodities",
        "label": "Commodities [Member]",
        "documentation": "This member stands for commodities."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CommodityPriceRiskMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CommodityPriceRiskMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Commodity risk",
        "terseLabel": "Commodity derivatives",
        "label": "Commodity price risk [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a component of other price risk that represents the type of risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in commodity prices. [Refer: Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r670",
      "r690"
     ]
    },
    "ifrs-full_CommunicationAndNetworkEquipmentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CommunicationAndNetworkEquipmentMember",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Equipment installed in freehold and leasehold property",
        "verboseLabel": "Equipment",
        "label": "Communication and network equipment [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a class of property, plant and equipment representing communications and network equipment. [Refer: Property, plant and equipment]"
       }
      }
     },
     "auth_ref": [
      "r838"
     ]
    },
    "ecd_CompActuallyPaidVsCoSelectedMeasureTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "CompActuallyPaidVsCoSelectedMeasureTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Compensation Actually Paid vs. Company Selected Measure [Text Block]",
        "terseLabel": "Compensation Actually Paid vs. Company Selected Measure"
       }
      }
     },
     "auth_ref": [
      "r789"
     ]
    },
    "ecd_CompActuallyPaidVsNetIncomeTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "CompActuallyPaidVsNetIncomeTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Compensation Actually Paid vs. Net Income [Text Block]",
        "terseLabel": "Compensation Actually Paid vs. Net Income"
       }
      }
     },
     "auth_ref": [
      "r788"
     ]
    },
    "ecd_CompActuallyPaidVsOtherMeasureTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "CompActuallyPaidVsOtherMeasureTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Compensation Actually Paid vs. Other Measure [Text Block]",
        "terseLabel": "Compensation Actually Paid vs. Other Measure"
       }
      }
     },
     "auth_ref": [
      "r790"
     ]
    },
    "ecd_CompActuallyPaidVsTotalShareholderRtnTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "CompActuallyPaidVsTotalShareholderRtnTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Compensation Actually Paid vs. Total Shareholder Return [Text Block]",
        "terseLabel": "Compensation Actually Paid vs. Total Shareholder Return"
       }
      }
     },
     "auth_ref": [
      "r787"
     ]
    },
    "ifrs-full_ComponentsOfEquityAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ComponentsOfEquityAxis",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Components of equity [axis]",
        "label": "Components of equity [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r555"
     ]
    },
    "ifrs-full_ComponentsOfEquityDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ComponentsOfEquityDomain",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Components of equity [domain]",
        "label": "Components of equity [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the residual interest in the assets of the entity after deducting all its liabilities. It also represents the standard value for the 'Components of equity' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r555"
     ]
    },
    "ifrs-full_ComponentsOfOtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTaxAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ComponentsOfOtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTaxAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other comprehensive income/(loss) that may be recycled to profit or loss:",
        "label": "Components of other comprehensive income that will be reclassified to profit or loss, net of tax [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ComponentsOfOtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTaxAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ComponentsOfOtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTaxAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other comprehensive income/(loss) not recycled to profit or loss:",
        "label": "Components of other comprehensive income that will not be reclassified to profit or loss, net of tax [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ComprehensiveIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ComprehensiveIncome",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      },
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      },
      "http://www.home.barclays/role/ConsolidatedstatementofcomprehensiveincomeDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total comprehensive income for the year",
        "label": "Comprehensive income"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of change in equity resulting from transactions and other events, other than those changes resulting from transactions with owners in their capacity as owners."
       }
      }
     },
     "auth_ref": [
      "r131",
      "r133",
      "r147",
      "r430",
      "r460",
      "r550",
      "r589",
      "r635"
     ]
    },
    "ifrs-full_ComprehensiveIncomeAttributableToAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ComprehensiveIncomeAttributableToAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Attributable to:",
        "label": "Comprehensive income attributable to [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ComprehensiveIncomeAttributableToOwnersOfParent": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ComprehensiveIncomeAttributableToOwnersOfParent",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/ConsolidatedstatementofcomprehensiveincomeDetails": {
       "parentTag": "ifrs-full_ComprehensiveIncome",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Equity holders of the parent",
        "label": "Comprehensive income, attributable to owners of parent"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of comprehensive income attributable to owners of the parent. [Refer: Comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r550",
      "r591"
     ]
    },
    "ifrs-full_ComputerEquipmentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ComputerEquipmentMember",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Computers and similar equipment",
        "label": "Computer equipment [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a class of property, plant and equipment representing computer equipment. [Refer: Property, plant and equipment]"
       }
      }
     },
     "auth_ref": [
      "r838"
     ]
    },
    "ifrs-full_ComputerSoftwareMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ComputerSoftwareMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Software",
        "label": "Computer software [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a class of intangible assets representing computer software. [Refer: Intangible assets other than goodwill]"
       }
      }
     },
     "auth_ref": [
      "r626"
     ]
    },
    "srt_CondensedBalanceSheetStatementTable": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "CondensedBalanceSheetStatementTable",
     "presentation": [
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/ParentcompanyaccountsbalancesheetParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Condensed Balance Sheet Statement [Table]",
        "label": "Condensed Balance Sheet Statement [Table]"
       }
      }
     },
     "auth_ref": []
    },
    "srt_CondensedBalanceSheetStatementsCaptionsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "CondensedBalanceSheetStatementsCaptionsLineItems",
     "presentation": [
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/ParentcompanyaccountsbalancesheetParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Condensed Balance Sheet Statements, Captions [Line Items]",
        "label": "Condensed Balance Sheet Statements, Captions [Line Items]"
       }
      }
     },
     "auth_ref": []
    },
    "srt_CondensedCashFlowStatementTable": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "CondensedCashFlowStatementTable",
     "presentation": [
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatementParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Condensed Cash Flow Statement [Table]",
        "label": "Condensed Cash Flow Statement [Table]"
       }
      }
     },
     "auth_ref": []
    },
    "srt_CondensedCashFlowStatementsCaptionsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "CondensedCashFlowStatementsCaptionsLineItems",
     "presentation": [
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatementParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Condensed Cash Flow Statements, Captions [Line Items]",
        "label": "Condensed Cash Flow Statements, Captions [Line Items]"
       }
      }
     },
     "auth_ref": []
    },
    "srt_CondensedStatementOfComprehensiveIncomeTable": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "CondensedStatementOfComprehensiveIncomeTable",
     "presentation": [
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincomeParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Condensed Statement of Comprehensive Income [Table]",
        "label": "Condensed Statement of Comprehensive Income [Table]"
       }
      }
     },
     "auth_ref": []
    },
    "srt_CondensedStatementOfIncomeCaptionsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "CondensedStatementOfIncomeCaptionsLineItems",
     "presentation": [
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincomeParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Condensed Statement of Income Captions [Line Items]",
        "label": "Condensed Statement of Income Captions [Line Items]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ConsiderationPaidReceived": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ConsiderationPaidReceived",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/AcquisitionandDisposalsofsubsidiariesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Consideration received",
        "label": "Consideration paid (received)"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of consideration paid or received in respect of both obtaining and losing control of subsidiaries or other businesses. [Refer: Total for all subsidiaries [member]]"
       }
      }
     },
     "auth_ref": [
      "r124"
     ]
    },
    "srt_ConsolidatedEntitiesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "ConsolidatedEntitiesAxis",
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresDisclosureofinvestmentsinassociatesandjointventuresDetails",
      "http://www.home.barclays/role/LeasesNarrativeDetails",
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatementParenthetical",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequityParenthetical",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincomeParenthetical",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/ParentcompanyaccountsbalancesheetParenthetical",
      "http://www.home.barclays/role/ProvisionsNarrativeDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Consolidated Entities [Axis]",
        "label": "Consolidated Entities [Axis]"
       }
      }
     },
     "auth_ref": []
    },
    "srt_ConsolidatedEntitiesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "ConsolidatedEntitiesDomain",
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresDisclosureofinvestmentsinassociatesandjointventuresDetails",
      "http://www.home.barclays/role/LeasesNarrativeDetails",
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatementParenthetical",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequityParenthetical",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincomeParenthetical",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/ParentcompanyaccountsbalancesheetParenthetical",
      "http://www.home.barclays/role/ProvisionsNarrativeDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Consolidated Entities [Domain]",
        "label": "Consolidated Entities [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "srt_ConsolidationEliminationsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "ConsolidationEliminationsMember",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Bank Group owned, not consolidated entities",
        "label": "Consolidation, Eliminations [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "srt_ConsolidationItemsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "ConsolidationItemsAxis",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Consolidation Items [Axis]",
        "label": "Consolidation Items [Axis]"
       }
      }
     },
     "auth_ref": []
    },
    "srt_ConsolidationItemsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "ConsolidationItemsDomain",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Consolidation Items [Domain]",
        "label": "Consolidation Items [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ConsumerLoansMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ConsumerLoansMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Issued debt",
        "label": "Loans to consumers [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for loans that are made to individuals for personal use."
       }
      }
     },
     "auth_ref": [
      "r671",
      "r687",
      "r691"
     ]
    },
    "dei_ContactPersonnelName": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "ContactPersonnelName",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Contact Personnel Name",
        "label": "Contact Personnel Name",
        "documentation": "Name of contact personnel"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ContingentLiabilitiesAndFinancialGuaranteesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ContingentLiabilitiesAndFinancialGuaranteesMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Contingent liabilities",
        "label": "Contingent Liabilities And Financial Guarantees [Member]",
        "documentation": "Contingent Liabilities And Financial Guarantees"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ContinuingInvolvementInDerecognisedFinancialAssetsByTypeOfTransferAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ContinuingInvolvementInDerecognisedFinancialAssetsByTypeOfTransferAxis",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureofcontinuinginvolvementinfinancialassetsthathavebeenderecognisedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Continuing involvement in derecognised financial assets by type of transfer [axis]",
        "label": "Continuing involvement in derecognised financial assets by type of transfer [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r676"
     ]
    },
    "ifrs-full_ContinuingInvolvementInDerecognisedFinancialAssetsByTypeOfTransferDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ContinuingInvolvementInDerecognisedFinancialAssetsByTypeOfTransferDomain",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureofcontinuinginvolvementinfinancialassetsthathavebeenderecognisedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Continuing involvement in derecognised financial assets by type of transfer [domain]",
        "label": "Continuing involvement in derecognised financial assets by type of transfer [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all types of transfers of financial instruments. It also represents the standard value for the 'Continuing involvement in derecognised financial assets by type of transfer' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r676"
     ]
    },
    "ifrs-full_ContractAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ContractAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Contract assets",
        "label": "Contract assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of an entity\u2019s right to consideration in exchange for goods or services that the entity has transferred to a customer, when that right is conditioned on something other than the passage of time (for example, the entity\u2019s future performance)."
       }
      }
     },
     "auth_ref": [
      "r178",
      "r183",
      "r358"
     ]
    },
    "ifrs-full_ContractLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ContractLiabilities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Contract liabilities",
        "label": "Contract liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of an entity\u2019s obligation to transfer goods or services to a customer for which the entity has received consideration (or the amount is due) from the customer."
       }
      }
     },
     "auth_ref": [
      "r178",
      "r183",
      "r358"
     ]
    },
    "bbplc_ContractualBackstopLiquidityFacilitiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ContractualBackstopLiquidityFacilitiesMember",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Contractual backstop liquidity facilities",
        "label": "Contractual Backstop Liquidity Facilities [Member]",
        "documentation": "This member stands for contractual Backstop Liquidity Facilities that would be utilised to refinance the debt obligations of a customer in situations where such a customer is unable to rollover that debt in financial markets."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ContractualCarryingAmountDueOnMaturityMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ContractualCarryingAmountDueOnMaturityMember",
     "presentation": [
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Contractual amount due on maturity",
        "label": "Contractual Carrying Amount Due On Maturity [Member]",
        "documentation": "This member stands for the component contractually required to pay at maturity to the holder of the obligation."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ContributionsToPlanByEmployerNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ContributionsToPlanByEmployerNetDefinedBenefitLiabilityAsset",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Employer contribution",
        "label": "Decrease (increase) in net defined benefit liability (asset) resulting from resulting from contributions to plan by employer"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease (increase) in net defined benefit liability (asset) resulting from contributions to a defined benefit plan by the employer. [Refer: Net defined benefit liability (asset); Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r30"
     ]
    },
    "ifrs-full_ContributionsToPlanByPlanParticipantsNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ContributionsToPlanByPlanParticipantsNetDefinedBenefitLiabilityAsset",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Employee contributions",
        "label": "Decrease (increase) in net defined benefit liability (asset) resulting from contributions to plan by plan participants"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease (increase) in the net defined benefit liability (asset) resulting from contributions to a defined benefit plan by plan participants. [Refer: Net defined benefit liability (asset); Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r30"
     ]
    },
    "ifrs-full_ContributionsToPlanNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ContributionsToPlanNetDefinedBenefitLiabilityAsset",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Defined benefit contributions paid",
        "label": "Decrease (increase) in net defined benefit liability (asset) resulting from contributions to plan"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease (increase) in the net defined benefit liability (asset) resulting from contributions to a defined benefit plan. [Refer: Net defined benefit liability (asset); Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r30",
      "r410"
     ]
    },
    "bbplc_CorporateClientTurnoverThreshold": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CorporateClientTurnoverThreshold",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/SegmentalreportingNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Corporate client turnover threshold",
        "label": "Corporate Client Turnover Threshold",
        "documentation": "Corporate Client Turnover Threshold"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CorporateLoansMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CorporateLoansMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Corporate loans",
        "verboseLabel": "Corporate debt",
        "label": "Loans to corporate entities [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for loans made to corporate entities."
       }
      }
     },
     "auth_ref": [
      "r671",
      "r687",
      "r880"
     ]
    },
    "ifrs-full_CounterpartiesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CounterpartiesAxis",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Counterparties [axis]",
        "label": "Counterparties [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r325"
     ]
    },
    "ifrs-full_CounterpartiesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CounterpartiesDomain",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Counterparties [domain]",
        "label": "Counterparties [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the parties to the transaction other than the entity. It also represents the standard value for the 'Counterparties' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r325"
     ]
    },
    "srt_CounterpartyNameAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "CounterpartyNameAxis",
     "presentation": [
      "http://www.home.barclays/role/AcquisitionandDisposalsofsubsidiariesDetails",
      "http://www.home.barclays/role/AuditorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Counterparty Name [Axis]",
        "label": "Counterparty Name [Axis]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CountryOfDomicileMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CountryOfDomicileMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "United Kingdom",
        "terseLabel": "UK",
        "label": "Country of domicile [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the country in which the entity is registered and where it has its legal address or registered office."
       }
      }
     },
     "auth_ref": [
      "r343",
      "r344"
     ]
    },
    "bbplc_CouponsPaidOnOtherEquityInstruments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CouponsPaidOnOtherEquityInstruments",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other equity instruments coupons paid",
        "label": "Coupons Paid On Other Equity Instruments",
        "documentation": "The amount of increase (decrease) in equity through other equity instruments coupons paid."
       }
      }
     },
     "auth_ref": []
    },
    "dei_CoverAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "CoverAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cover [Abstract]",
        "label": "Cover [Abstract]",
        "documentation": "Cover page."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CreditCardsRetailMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CreditCardsRetailMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails",
      "http://www.home.barclays/role/SecuritisationsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Retail credit cards",
        "label": "Credit Cards, Retail [Member]",
        "documentation": "This member stands for a class of financial assets that represents credit cards, unsecured and other retail lending."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_CreditCardsUnsecuredLoansAndOtherRetailLendingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CreditCardsUnsecuredLoansAndOtherRetailLendingMember",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Credit cards, unsecured loans and other retail lending",
        "label": "Credit Cards, Unsecured Loans And Other Retail Lending [Member]",
        "documentation": "This member stands for a class of financial assets that represents credit cards, unsecured and other retail lending."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CreditImpairmentOfFinancialInstrumentsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CreditImpairmentOfFinancialInstrumentsAxis",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Credit impairment of financial instruments [axis]",
        "label": "Credit impairment of financial instruments [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r285",
      "r296",
      "r511",
      "r517"
     ]
    },
    "ifrs-full_CreditImpairmentOfFinancialInstrumentsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CreditImpairmentOfFinancialInstrumentsDomain",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Credit impairment of financial instruments [domain]",
        "label": "Credit impairment of financial instruments [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all statuses of credit impairment of financial instruments. A financial instrument is credit-impaired when one or more events that have a detrimental impact on the estimated future cash flows of that financial instrument have occurred. This member also represents the standard value for the 'Credit impairment of financial instruments' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r285",
      "r296",
      "r511",
      "r517"
     ]
    },
    "ifrs-full_CreditRiskMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CreditRiskMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Credit risk",
        "netLabel": "Weighted",
        "terseLabel": "Credit derivatives",
        "label": "Credit risk [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the risk that one party to a financial instrument will cause a financial loss for the other party by failing to discharge an obligation. [Refer: Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r203",
      "r204",
      "r205",
      "r661"
     ]
    },
    "ifrs-full_CreditSpreadMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CreditSpreadMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Credit spread",
        "label": "Credit spread, measurement input [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the credit spread used as a measurement input."
       }
      }
     },
     "auth_ref": [
      "r869"
     ]
    },
    "bbplc_CubeSolidusBVMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CubeSolidusBVMember",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cube Solidus B.V.",
        "label": "Cube Solidus BV [Member]",
        "documentation": "Cube Solidus BV"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CumulativeGainLossOnDisposalOfInvestmentsInEquityInstrumentsDesignatedAsMeasuredAtFairValueThroughOtherComprehensiveIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CumulativeGainLossOnDisposalOfInvestmentsInEquityInstrumentsDesignatedAsMeasuredAtFairValueThroughOtherComprehensiveIncome",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails": {
       "parentTag": "bbplc_NetInvestmentIncomeExpense",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net (losses)/gains from disposal of financial assets at fair value through other comprehensive income",
        "label": "Cumulative gain (loss) on disposal of investments in equity instruments designated at fair value through other comprehensive income"
       }
      },
      "en": {
       "role": {
        "documentation": "The cumulative gain (loss) on disposal of investments in equity instruments that the entity has designated at fair value through other comprehensive income. [Refer: At fair value [member]; Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r238"
     ]
    },
    "srt_CurrencyAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "CurrencyAxis",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Currency [Axis]",
        "label": "Currency [Axis]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CurrencyRiskMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CurrencyRiskMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Foreign exchange risk",
        "terseLabel": "Foreign exchange derivatives",
        "label": "Currency risk [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a type of market risk representing the risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in foreign exchange rates. [Refer: Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r203",
      "r204",
      "r205",
      "r207",
      "r328"
     ]
    },
    "ifrs-full_CurrentEstimateOfFutureCashOutflowsToBePaidToFulfilObligationMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CurrentEstimateOfFutureCashOutflowsToBePaidToFulfilObligationMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Inflation forwards",
        "label": "Current estimate of future cash outflows to be paid to fulfil obligation, measurement input [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the current estimate of future cash outflows to be paid to fulfil obligation, used as a measurement input."
       }
      }
     },
     "auth_ref": [
      "r646"
     ]
    },
    "dei_CurrentFiscalYearEndDate": {
     "xbrltype": "gMonthDayItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "CurrentFiscalYearEndDate",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Current Fiscal Year End Date",
        "label": "Current Fiscal Year End Date",
        "documentation": "End date of current fiscal year in the format --MM-DD."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CurrentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CurrentMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Not past due",
        "terseLabel": "2025",
        "label": "Current [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a current time band."
       }
      }
     },
     "auth_ref": [
      "r669",
      "r688"
     ]
    },
    "ifrs-full_CurrentServiceCostNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CurrentServiceCostNetDefinedBenefitLiabilityAsset",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofincomestatementchargeDetails": {
       "parentTag": "ifrs-full_IncreaseDecreaseInNetDefinedBenefitLiabilityAsset",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofincomestatementchargeDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Current service cost",
        "negatedTerseLabel": "Current service cost",
        "label": "Increase in net defined benefit liability (asset) resulting from current service cost"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in the net defined benefit liability (asset) resulting from employee service in the current period. [Refer: Net defined benefit liability (asset)]"
       }
      }
     },
     "auth_ref": [
      "r23",
      "r407"
     ]
    },
    "ifrs-full_CurrentTaxAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CurrentTaxAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 15.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Current tax assets",
        "label": "Current tax assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The excess of amount paid for current tax in respect of current and prior periods over the amount due for those periods. Current tax is the amount of income taxes payable (recoverable) in respect of the taxable profit (tax loss) for a period."
       }
      }
     },
     "auth_ref": [
      "r572"
     ]
    },
    "ifrs-full_CurrentTaxExpenseIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CurrentTaxExpenseIncome",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails": {
       "parentTag": "ifrs-full_CurrentTaxExpenseIncomeAndAdjustmentsForCurrentTaxOfPriorPeriods",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Current year",
        "label": "Current tax expense (income)"
       }
      }
     },
     "auth_ref": [
      "r606",
      "r700"
     ]
    },
    "ifrs-full_CurrentTaxExpenseIncomeAndAdjustmentsForCurrentTaxOfPriorPeriods": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CurrentTaxExpenseIncomeAndAdjustmentsForCurrentTaxOfPriorPeriods",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total",
        "label": "Current tax expense (income) and adjustments for current tax of prior periods"
       }
      }
     },
     "auth_ref": [
      "r835"
     ]
    },
    "ifrs-full_CurrentTaxExpenseIncomeAndAdjustmentsForCurrentTaxOfPriorPeriodsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CurrentTaxExpenseIncomeAndAdjustmentsForCurrentTaxOfPriorPeriodsAbstract",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Current tax charge/(credit)",
        "label": "Current tax expense (income) and adjustments for current tax of prior periods [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CurrentTaxExpenseIncomeRelatedToPillarTwoIncomeTaxes": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CurrentTaxExpenseIncomeRelatedToPillarTwoIncomeTaxes",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Additional taxes related to Pillar Two",
        "label": "Current tax expense (income), related to Pillar Two income taxes"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of current tax expense (income) related to Pillar Two income taxes."
       }
      }
     },
     "auth_ref": [
      "r11",
      "r398"
     ]
    },
    "ifrs-full_CurrentTaxLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CurrentTaxLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 10.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Current tax liabilities",
        "label": "Current tax liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of current tax for current and prior periods to the extent unpaid. Current tax is the amount of income taxes payable (recoverable) in respect of the taxable profit (tax loss) for a period."
       }
      }
     },
     "auth_ref": [
      "r572"
     ]
    },
    "ifrs-full_CurrentTaxRelatingToItemsChargedOrCreditedDirectlyToEquity": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CurrentTaxRelatingToItemsChargedOrCreditedDirectlyToEquity",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Tax relating to items credited directly to equity",
        "label": "Current tax relating to items credited (charged) directly to equity"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of current tax relating to particular items that are charged or credited directly to equity, for example: (a) an adjustment to the opening balance of retained earnings resulting from either a change in accounting policy that is applied retrospectively or the correction of an error; and (b) amounts arising on initial recognition of the equity component of a compound financial instrument. [Refer: Retained earnings; Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r2",
      "r391"
     ]
    },
    "bbplc_CustomerRedressMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "CustomerRedressMember",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Customer redress",
        "label": "Customer Redress [Member]",
        "documentation": "This member stands for a provision for customer redress provisions comprise the estimated cost of making redress payments to customers, clients and counterparties for losses or damages associated with inappropriate judgement in the execution of our business activities."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_CustomerrelatedIntangibleAssetsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "CustomerrelatedIntangibleAssetsMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Customer lists",
        "label": "Customer-related intangible assets [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a class of intangible assets representing assets related to customers. Such assets may include customer lists, order or production backlog, customer contracts and related customer relationships as well as non-contractual customer relationships."
       }
      }
     },
     "auth_ref": [
      "r859"
     ]
    },
    "cyd_CybersecurityRiskBoardCommitteeOrSubcommitteeResponsibleForOversightTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskBoardCommitteeOrSubcommitteeResponsibleForOversightTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]"
       }
      }
     },
     "auth_ref": [
      "r735",
      "r824"
     ]
    },
    "cyd_CybersecurityRiskBoardOfDirectorsOversightTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskBoardOfDirectorsOversightTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Board of Directors Oversight [Text Block]"
       }
      }
     },
     "auth_ref": [
      "r735",
      "r824"
     ]
    },
    "cyd_CybersecurityRiskManagementExpertiseOfManagementResponsibleTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskManagementExpertiseOfManagementResponsibleTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Management Expertise of Management Responsible [Text Block]"
       }
      }
     },
     "auth_ref": [
      "r737",
      "r826"
     ]
    },
    "cyd_CybersecurityRiskManagementPositionsOrCommitteesResponsibleFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskManagementPositionsOrCommitteesResponsibleFlag",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Management Positions or Committees Responsible [Flag]"
       }
      }
     },
     "auth_ref": [
      "r737",
      "r826"
     ]
    },
    "cyd_CybersecurityRiskManagementPositionsOrCommitteesResponsibleReportToBoardFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskManagementPositionsOrCommitteesResponsibleReportToBoardFlag",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]"
       }
      }
     },
     "auth_ref": [
      "r739",
      "r828"
     ]
    },
    "cyd_CybersecurityRiskManagementPositionsOrCommitteesResponsibleTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskManagementPositionsOrCommitteesResponsibleTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Management Positions or Committees Responsible [Text Block]"
       }
      }
     },
     "auth_ref": [
      "r737",
      "r826"
     ]
    },
    "cyd_CybersecurityRiskManagementProcessesForAssessingIdentifyingAndManagingThreatsTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskManagementProcessesForAssessingIdentifyingAndManagingThreatsTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]"
       }
      }
     },
     "auth_ref": [
      "r730",
      "r819"
     ]
    },
    "cyd_CybersecurityRiskManagementProcessesIntegratedFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskManagementProcessesIntegratedFlag",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Management Processes Integrated [Flag]"
       }
      }
     },
     "auth_ref": [
      "r731",
      "r820"
     ]
    },
    "cyd_CybersecurityRiskManagementProcessesIntegratedTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskManagementProcessesIntegratedTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Management Processes Integrated [Text Block]"
       }
      }
     },
     "auth_ref": [
      "r731",
      "r820"
     ]
    },
    "cyd_CybersecurityRiskManagementStrategyAndGovernanceAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskManagementStrategyAndGovernanceAbstract",
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Management, Strategy, and Governance [Abstract]"
       }
      }
     },
     "auth_ref": [
      "r729",
      "r818"
     ]
    },
    "cyd_CybersecurityRiskManagementStrategyAndGovernanceLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskManagementStrategyAndGovernanceLineItems",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Management, Strategy, and Governance [Line Items]"
       }
      }
     },
     "auth_ref": [
      "r729",
      "r818"
     ]
    },
    "cyd_CybersecurityRiskManagementStrategyAndGovernanceTable": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskManagementStrategyAndGovernanceTable",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Management, Strategy, and Governance [Table]"
       }
      }
     },
     "auth_ref": [
      "r729",
      "r818"
     ]
    },
    "cyd_CybersecurityRiskManagementThirdPartyEngagedFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskManagementThirdPartyEngagedFlag",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Management Third Party Engaged [Flag]"
       }
      }
     },
     "auth_ref": [
      "r732",
      "r821"
     ]
    },
    "cyd_CybersecurityRiskMateriallyAffectedOrReasonablyLikelyToMateriallyAffectRegistrantFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskMateriallyAffectedOrReasonablyLikelyToMateriallyAffectRegistrantFlag",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]"
       }
      }
     },
     "auth_ref": [
      "r734",
      "r823"
     ]
    },
    "cyd_CybersecurityRiskMateriallyAffectedOrReasonablyLikelyToMateriallyAffectRegistrantTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskMateriallyAffectedOrReasonablyLikelyToMateriallyAffectRegistrantTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Text Block]"
       }
      }
     },
     "auth_ref": [
      "r734",
      "r823"
     ]
    },
    "cyd_CybersecurityRiskProcessForInformingBoardCommitteeOrSubcommitteeResponsibleForOversightTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskProcessForInformingBoardCommitteeOrSubcommitteeResponsibleForOversightTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]"
       }
      }
     },
     "auth_ref": [
      "r735",
      "r824"
     ]
    },
    "cyd_CybersecurityRiskProcessForInformingManagementOrCommitteesResponsibleTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskProcessForInformingManagementOrCommitteesResponsibleTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]"
       }
      }
     },
     "auth_ref": [
      "r738",
      "r827"
     ]
    },
    "cyd_CybersecurityRiskRoleOfManagementTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskRoleOfManagementTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Role of Management [Text Block]"
       }
      }
     },
     "auth_ref": [
      "r736",
      "r825"
     ]
    },
    "cyd_CybersecurityRiskThirdPartyOversightAndIdentificationProcessesFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/cyd/2025",
     "localname": "CybersecurityRiskThirdPartyOversightAndIdentificationProcessesFlag",
     "presentation": [
      "http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]"
       }
      }
     },
     "auth_ref": [
      "r733",
      "r822"
     ]
    },
    "ifrs-full_DatedSubordinatedLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DatedSubordinatedLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedanddatedsubordinatedliabilitiesDetails": {
       "parentTag": "bbplc_SubordinatedLiabilitiesIncludingThoseDesignatedAtFairValue",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedanddatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Dated subordinated liabilities",
        "label": "Dated subordinated liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of subordinated liabilities that have a specified repayment date. [Refer: Subordinated liabilities]"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "bbplc_DatedSubordinatedLiabilitiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DatedSubordinatedLiabilitiesMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Dated subordinated liabilities",
        "label": "Dated Subordinated Liabilities [Member]",
        "documentation": "This member stands for the dated subordinated liabilities of the entity measured at amortised cost using the effective interest method under IFRS 9."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DebtInstrumentsAmountContributedToFairValueOfPlanAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DebtInstrumentsAmountContributedToFairValueOfPlanAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails": {
       "parentTag": "ifrs-full_PlanAssetsAtFairValue",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Bonds",
        "verboseLabel": "Debt instruments",
        "label": "Debt instruments, amount contributed to fair value of plan assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount instruments representing debt (rather than equity) contribute to the fair value of defined benefit plan assets. [Refer: Plan assets, at fair value; Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r615",
      "r703"
     ]
    },
    "ifrs-full_DebtInstrumentsHeld": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DebtInstrumentsHeld",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails": {
       "parentTag": "ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLoss",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Debt securities",
        "label": "Debt instruments held"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of instruments representing indebtedness, including instruments called debt securities, held by the entity."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_DebtInstrumentsHeldAtAmortisedCost": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DebtInstrumentsHeldAtAmortisedCost",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 4.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialAssets",
       "weight": 1.0,
       "order": 6.0
      },
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 6.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Debt securities at amortised cost",
        "terseLabel": "Debt instruments held at amortised cost",
        "label": "Debt instruments held at amortised cost"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of instruments representing indebtedness held by the entity at amortised cost. [Refer: Debt instruments held; Financial assets at amortised cost]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_DebtInstrumentsHeldAtAmortisedCostPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DebtInstrumentsHeldAtAmortisedCostPercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Debt securities at amortised cost, percentage",
        "label": "Debt Instruments Held At Amortised Cost, Percentage",
        "documentation": "Debt Instruments Held At Amortised Cost, Percentage"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DebtInstrumentsIssuedAtAmortisedCost": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DebtInstrumentsIssuedAtAmortisedCost",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 5.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialLiabilities",
       "weight": 1.0,
       "order": 9.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Debt securities in issue",
        "negatedLabel": "Debt securities in issue",
        "label": "Debt instruments issued at amortised cost"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of instruments issued by the entity that represent indebtedness at amortised cost. [Refer: Financial liabilities at amortised cost]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_DebtSecurities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DebtSecurities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails": {
       "parentTag": "ifrs-full_FinancialLiabilitiesAtFairValueThroughProfitOrLossDesignatedAsUponInitialRecognition",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Debt securities",
        "label": "Debt instruments issued"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of instruments issued by the entity that represent indebtedness."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_DebtSecuritiesInIssueUndiscountedCashFlows": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DebtSecuritiesInIssueUndiscountedCashFlows",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails": {
       "parentTag": "bbplc_TotalFinancialLiabilitiesUndiscounted",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Debt securities in issue, undiscounted",
        "label": "Debt Securities In Issue, Undiscounted Cash Flows",
        "documentation": "The amount of contractual undiscounted cash flows in relation to debt instruments issued."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DebtSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DebtSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughothercomprehensiveincomeDetails",
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails",
      "http://www.home.barclays/role/TradingportfolioDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Debt securities",
        "verboseLabel": "Debt securities at amortised cost",
        "netLabel": "Debt securities and other eligible bills",
        "label": "Debt securities [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for instruments held by the entity that represent indebtedness."
       }
      }
     },
     "auth_ref": [
      "r640",
      "r650"
     ]
    },
    "bbplc_DecreaseForEarlyTerminationOptionExpectedToBeExercisedGrossLeaseLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DecreaseForEarlyTerminationOptionExpectedToBeExercisedGrossLeaseLiabilities",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/LeasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash flow reduced for early termination option expected to be exercised",
        "label": "Decrease For Early Termination Option Expected To Be Exercised, Gross Lease Liabilities",
        "documentation": "Decrease For Early Termination Option Expected To Be Exercised, Gross Lease Liabilities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DecreaseInActuarialAssumptionDuration": {
     "xbrltype": "durationItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DecreaseInActuarialAssumptionDuration",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Decrease in actuarial assumption, duration",
        "label": "Decrease In Actuarial Assumption, Duration",
        "documentation": "Decrease In Actuarial Assumption, Duration"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DecreaseInFairValueMeasurementDueToChangeInMultipleUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsRecognisedInOCIAfterTaxAssetsLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DecreaseInFairValueMeasurementDueToChangeInMultipleUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsRecognisedInOCIAfterTaxAssetsLiabilities",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Unfavourable changes, Equity",
        "label": "Decrease In Fair Value Measurement Due To Change In Multiple Unobservable Inputs To Reflect Reasonably Possible Alternative Assumptions, Recognised In OCI, After Tax, Assets (Liabilities)",
        "documentation": "The amount of decrease in the fair value measurement of assets (liabilities), recognised in other comprehensive income after tax, due to a change in multiple unobservable inputs to reflect reasonably possible alternative assumptions. [Refer: Tax income (expense)]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DecreaseInFairValueMeasurementDueToChangeInMultipleUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsRecognisedInProfitOrLossAfterTaxAssetsLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DecreaseInFairValueMeasurementDueToChangeInMultipleUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsRecognisedInProfitOrLossAfterTaxAssetsLiabilities",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Unfavourable changes, Income Statement",
        "label": "Decrease In Fair Value Measurement Due To Change In Multiple Unobservable Inputs To Reflect Reasonably Possible Alternative Assumptions, Recognised In Profit Or Loss, After Tax, Assets (Liabilities)",
        "documentation": "The amount of decrease in the fair value measurement of assets (liabilities), recognised in profit or loss after tax, due to a change in multiple unobservable inputs to reflect reasonably possible alternative assumptions. [Refer: Tax income (expense)]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DecreaseInFairValueMeasurementDueToChangeInOneOrMoreUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsAssetsLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DecreaseInFairValueMeasurementDueToChangeInOneOrMoreUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsAssetsLiabilities",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Unfavorable changes",
        "label": "Decrease In Fair Value Measurement Due To Change In One Or More Unobservable Inputs To Reflect Reasonably Possible Alternative Assumptions, Assets (Liabilities)",
        "documentation": "The amount of decrease in the fair value measurement of assets and liabilities due to a change in one or more unobservable inputs to reflect reasonably possible alternative assumptions."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DecreaseThroughDerecognitionExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DecreaseThroughDerecognitionExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Limit management and final repayments",
        "label": "Decrease through derecognition, exposure to credit risk on loan commitments and financial guarantee contracts"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease in exposure to credit risk on loan commitments and financial guarantee contracts resulting from derecognition. [Refer: Exposure to credit risk on loan commitments and financial guarantee contracts]"
       }
      }
     },
     "auth_ref": [
      "r662",
      "r665",
      "r686",
      "r707",
      "r710"
     ]
    },
    "ifrs-full_DecreaseThroughDerecognitionFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DecreaseThroughDerecognitionFinancialAssets",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Disposals",
        "label": "Decrease through derecognition, financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease in financial assets resulting from derecognition. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r662",
      "r665",
      "r686",
      "r707",
      "r710"
     ]
    },
    "bbplc_DecreaseThroughDisposalExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DecreaseThroughDisposalExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Disposals",
        "label": "Decrease Through Disposal, Exposure to Credit Risk on Loan Commitments and Financial Guarantee Contracts",
        "documentation": "Decrease Through Disposal, Exposure to Credit Risk on Loan Commitments and Financial Guarantee Contracts"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DecreaseThroughFinalRepaymentsFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DecreaseThroughFinalRepaymentsFinancialAssets",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Final repayments",
        "label": "Decrease Through Final Repayments, Financial Assets",
        "documentation": "Decrease Through Final Repayments, Financial Assets"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DecreaseThroughRedemptionOfPreferenceShares": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DecreaseThroughRedemptionOfPreferenceShares",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Redemption of preference shares",
        "label": "Decrease Through Redemption of Preference Shares",
        "documentation": "Decrease Through Redemption of Preference Shares"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DecreaseThroughTransfersToAssetsHeldForSaleFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DecreaseThroughTransfersToAssetsHeldForSaleFinancialAssets",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Transfers to assets held for sale",
        "label": "Decrease Through Transfers To Assets Held For Sale, Financial Assets",
        "documentation": "Decrease Through Transfers To Assets Held For Sale, Financial Assets"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DecreaseThroughWriteoffFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DecreaseThroughWriteoffFinancialAssets",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Write-offs",
        "label": "Decrease through write-off, financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease in financial assets resulting from write-off. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r662",
      "r665",
      "r686",
      "r707",
      "r710"
     ]
    },
    "ifrs-full_DeductibleTemporaryDifferencesForWhichNoDeferredTaxAssetIsRecognised": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DeductibleTemporaryDifferencesForWhichNoDeferredTaxAssetIsRecognised",
     "presentation": [
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Deductible temporary differences for which no deferred tax asset is recognised",
        "label": "Deductible temporary differences for which no deferred tax asset is recognised"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of deductible temporary differences for which no deferred tax asset is recognised in the statement of financial position. [Refer: Temporary differences [member]]"
       }
      }
     },
     "auth_ref": [
      "r6",
      "r394"
     ]
    },
    "bbplc_DeferredMembersAfterworkMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DeferredMembersAfterworkMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Deferred members (Afterwork)",
        "label": "Deferred Members, Afterwork [Member]",
        "documentation": "Deferred Members, Afterwork"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DeferredMembersNonAfterworkMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DeferredMembersNonAfterworkMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Deferred members (Non-Afterwork)",
        "label": "Deferred Members, Non-Afterwork [Member]",
        "documentation": "Deferred Members, Non-Afterwork"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DeferredShareValuePlanShareValuePlanMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DeferredShareValuePlanShareValuePlanMember",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofsharebasedpaymentschemesDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Share Value Plan and Deferred Share Value Plan",
        "verboseLabel": "SVP and DSVP",
        "label": "Deferred Share Value Plan / Share Value Plan [Member]",
        "documentation": "This member stands for the deferred share value plan, which was introduced in February 2017 in addition to the Share Value Plan, which was introduced in March 2010 and approved by shareholders (for Executive Director participation and use of new issue shares) at the AGM in April 2011."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DeferredTaxAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DeferredTaxAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_DeferredTaxLiabilityAsset",
       "weight": -1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 16.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Deferred tax assets",
        "label": "Deferred tax assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amounts of income taxes recoverable in future periods in respect of: (a) deductible temporary differences; (b) the carryforward of unused tax losses; and (c) the carryforward of unused tax credits. [Refer: Temporary differences [member]; Unused tax credits [member]; Unused tax losses [member]]"
       }
      }
     },
     "auth_ref": [
      "r8",
      "r395",
      "r573",
      "r576"
     ]
    },
    "bbplc_DeferredTaxAssetsBeforeOffsetting": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DeferredTaxAssetsBeforeOffsetting",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails": {
       "parentTag": "bbplc_DeferredTaxLiabilityAssetBeforeOffsetting",
       "weight": -1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "periodStartLabel": "Assets, beginning balance",
        "periodEndLabel": "Assets, ending balance",
        "label": "Deferred Tax Assets, Before Offsetting",
        "documentation": "The amounts of income taxes recoverable in future periods in respect of: (a) deductible temporary differences; (b) the carryforward of unused tax losses; and (c) the carryforward of unused tax credits before offsetting asset and liability balances where there is a legal right to set-off and an intention to settle on a net basis."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DeferredTaxExpenseIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DeferredTaxExpenseIncome",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails": {
       "parentTag": "ifrs-full_DeferredTaxExpenseIncomeRecognisedInProfitOrLoss",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Current year",
        "label": "Deferred tax expense (income)"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of tax expense (income) relating to changes in deferred tax liabilities and deferred tax assets. [Refer: Deferred tax assets; Deferred tax liabilities]"
       }
      }
     },
     "auth_ref": [
      "r9",
      "r396"
     ]
    },
    "ifrs-full_DeferredTaxExpenseIncomeAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DeferredTaxExpenseIncomeAbstract",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Deferred tax charge",
        "label": "Deferred tax expense (income) [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DeferredTaxExpenseIncomeRecognisedInProfitOrLoss": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DeferredTaxExpenseIncomeRecognisedInProfitOrLoss",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total",
        "negatedLabel": "Income statement",
        "label": "Deferred tax expense (income) recognised in profit or loss"
       }
      }
     },
     "auth_ref": [
      "r9",
      "r396"
     ]
    },
    "ifrs-full_DeferredTaxLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DeferredTaxLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_DeferredTaxLiabilityAsset",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 11.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Deferred tax liabilities",
        "negatedLabel": "Deferred tax liability",
        "label": "Deferred tax liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amounts of income taxes payable in future periods in respect of taxable temporary differences. [Refer: Temporary differences [member]]"
       }
      }
     },
     "auth_ref": [
      "r8",
      "r395",
      "r573",
      "r576"
     ]
    },
    "bbplc_DeferredTaxLiabilitiesBeforeOffsetting": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DeferredTaxLiabilitiesBeforeOffsetting",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails": {
       "parentTag": "bbplc_DeferredTaxLiabilityAssetBeforeOffsetting",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedPeriodStartLabel": "Liabilities, beginning balance",
        "negatedPeriodEndLabel": "Liabilities, ending balance",
        "label": "Deferred Tax Liabilities, Before Offsetting",
        "documentation": "The amounts of income taxes payable in future periods in respect of taxable temporary differences before offsetting asset and liability balances where there is a legal right to set-off and an intention to settle on a net basis."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DeferredTaxLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DeferredTaxLiabilityAsset",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTotalLabel": "Net deferred tax",
        "label": "Deferred tax liability (asset)"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of deferred tax liabilities or assets. [Refer: Deferred tax liabilities; Deferred tax assets]"
       }
      }
     },
     "auth_ref": [
      "r8",
      "r395"
     ]
    },
    "bbplc_DeferredTaxLiabilityAssetBeforeOffsetting": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DeferredTaxLiabilityAssetBeforeOffsetting",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedPeriodStartLabel": "Assets (liabilities), beginning balance",
        "negatedPeriodEndLabel": "Assets (liabilities), ending balance",
        "label": "Deferred Tax Liability (Asset), Before Offsetting",
        "documentation": "The amount of deferred tax liabilities or assets before offsetting asset and liability balances where there is a legal right to set-off and an intention to settle on a net basis."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DefinedBenefitObligationAtPresentValue": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DefinedBenefitObligationAtPresentValue",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Defined benefit obligation, at present value",
        "label": "Defined benefit obligation, at present value"
       }
      },
      "en": {
       "role": {
        "documentation": "The present value, without deducting any plan assets, of expected future payments required to settle the obligation resulting from employee service in the current and prior periods. [Refer: Plan assets, at fair value]"
       }
      }
     },
     "auth_ref": [
      "r849"
     ]
    },
    "ifrs-full_DefinedBenefitPlansAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DefinedBenefitPlansAxis",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Defined benefit plans [axis]",
        "label": "Defined benefit plans [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r19",
      "r403"
     ]
    },
    "ifrs-full_DefinedBenefitPlansDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DefinedBenefitPlansDomain",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Defined benefit plans [domain]",
        "label": "Defined benefit plans [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for post-employment benefit plans other than defined contribution plans. Defined contribution plans are post-employment benefit plans under which an entity pays fixed contributions into a separate entity (a fund) and will have no legal or constructive obligation to pay further contributions if the fund does not hold sufficient assets to pay all employee benefits relating to employee service in the current and prior periods. It also represents the standard value for the 'Defined benefit plans' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r19",
      "r403"
     ]
    },
    "ifrs-full_DefinedBenefitPlansOtherThanMultiemployerPlansStatePlansAndPlansThatShareRisksBetweenEntitiesUnderCommonControlMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DefinedBenefitPlansOtherThanMultiemployerPlansStatePlansAndPlansThatShareRisksBetweenEntitiesUnderCommonControlMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "UKRF",
        "label": "Defined benefit plans other than multi-employer plans, state plans and plans that share risks between entities under common control [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for defined benefit plans other than multi-employer plans, state plans and plans that share risks between entities under common control. [Refer: Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r19",
      "r403"
     ]
    },
    "bbplc_DefinedContributionPlansMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DefinedContributionPlansMember",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Defined contribution schemes",
        "label": "Defined Contribution Plans [Member]",
        "documentation": "This members stands for post-employment benefit plans under which an entity pays fixed contributions into a separate entity (a fund) and will have no legal or constructive obligation to pay further contributions if the fund does not hold sufficient assets to pay all employee benefits relating to employee service in the current and prior periods."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DepositLiabilitiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DepositLiabilitiesMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Deposits at amortised cost from banks and customers",
        "label": "Deposit Liabilities [Member]",
        "documentation": "Deposit Liabilities"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DepositsAtAmortisedCost": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DepositsAtAmortisedCost",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialLiabilities",
       "weight": 1.0,
       "order": 6.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Deposits at amortised cost from bank and customers",
        "negatedTerseLabel": "Deposits at amortised cost",
        "label": "Deposits at amortised cost"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of deposit liabilities held by the entity at amortised cost. [Refer: Financial liabilities at amortised cost]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_DepositsAtAmortisedCostUndiscountedCashFlows": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DepositsAtAmortisedCostUndiscountedCashFlows",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails": {
       "parentTag": "bbplc_TotalFinancialLiabilitiesUndiscounted",
       "weight": 1.0,
       "order": 6.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Deposits at amortised cost from banks and customers, undiscounted",
        "label": "Deposits At Amortised Cost, Undiscounted Cash Flows",
        "documentation": "The amount of contractual undiscounted cash flows in relation to deposits from banks."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DepositsFromBanksAndCustomers": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DepositsFromBanksAndCustomers",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails": {
       "parentTag": "ifrs-full_FinancialLiabilitiesAtFairValueThroughProfitOrLossDesignatedAsUponInitialRecognition",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Deposits",
        "label": "Deposits",
        "documentation": "The amount of deposit liabilities from banks and customers held by the entity."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DepositsFromBanksAtAmortisedCost": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DepositsFromBanksAtAmortisedCost",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Deposits at amortised cost from banks",
        "label": "Deposits from banks at amortised cost"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of deposit liabilities from banks held by the entity at amortised cost. [Refer: Financial liabilities at amortised cost]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_DepositsFromCustomers": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DepositsFromCustomers",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails": {
       "parentTag": "ifrs-full_LiabilitiesIncludedInDisposalGroupsClassifiedAsHeldForSale",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Deposits from customers",
        "label": "Deposits from customers"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of deposit liabilities from customers held by the entity."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_DepositsFromCustomersAtAmortisedCost": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DepositsFromCustomersAtAmortisedCost",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Deposits at amortised cost from customers",
        "label": "Deposits from customers at amortised cost"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of deposit liabilities from customers held by the entity at amortised cost. [Refer: Financial liabilities at amortised cost]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_DepreciationAndAmortisationExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DepreciationAndAmortisationExpense",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails": {
       "parentTag": "bbplc_InfrastructureCosts",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Depreciation and amortisation",
        "label": "Depreciation and amortisation expense"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of depreciation and amortisation expense. Depreciation and amortisation are the systematic allocations of depreciable amounts of assets over their useful lives."
       }
      }
     },
     "auth_ref": [
      "r150",
      "r332",
      "r340",
      "r549",
      "r605",
      "r716"
     ]
    },
    "ifrs-full_DepreciationPropertyPlantAndEquipmentIncludingRightofuseAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DepreciationPropertyPlantAndEquipmentIncludingRightofuseAssets",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Depreciation charge",
        "label": "Depreciation, property, plant and equipment including right-of-use assets"
       }
      }
     },
     "auth_ref": [
      "r840"
     ]
    },
    "ifrs-full_DepreciationRatePropertyPlantAndEquipment": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DepreciationRatePropertyPlantAndEquipment",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Depreciation rate",
        "label": "Depreciation rate, property, plant and equipment"
       }
      },
      "en": {
       "role": {
        "documentation": "The depreciation rate used for property, plant and equipment. [Refer: Property, plant and equipment]"
       }
      }
     },
     "auth_ref": [
      "r13",
      "r399"
     ]
    },
    "bbplc_DerivativeCreditValuationAdjustmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DerivativeCreditValuationAdjustmentsMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureoffairvalueadjustmentsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Derivative credit valuation adjustments",
        "label": "Derivative Credit Valuation Adjustments [Member]",
        "documentation": "This member stands for derivative credit valuation adjustment for the impact on fair value of counterparty credit risk."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DerivativeDebitValuationAdjustmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DerivativeDebitValuationAdjustmentsMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureoffairvalueadjustmentsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Derivative debit valuation adjustments",
        "label": "Derivative Debit Valuation Adjustments [Member]",
        "documentation": "This member stands for derivative debit valuation adjustment for the impact on fair value of the entoty's own credit quality."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DerivativeFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DerivativeFinancialAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails": {
       "parentTag": "ifrs-full_FinancialAssetsAtFairValue",
       "weight": 1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 8.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 9.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialAssets",
       "weight": 1.0,
       "order": 11.0
      },
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      },
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Derivative\u00a0financial instruments",
        "totalLabel": "Derivative assets",
        "verboseLabel": "Derivative financial assets",
        "label": "Derivative financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial assets classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_DerivativeFinancialAssetsAndRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DerivativeFinancialAssetsAndRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total assets",
        "label": "Derivative Financial Assets And Repurchase Agreements And Cash Collateral On Securities Borrowed",
        "documentation": "Derivative Financial Assets And Repurchase Agreements And Cash Collateral On Securities Borrowed"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DerivativeFinancialAssetsHeldForHedging": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DerivativeFinancialAssetsHeldForHedging",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails": {
       "parentTag": "ifrs-full_DerivativeFinancialAssets",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Derivative assets held for held for risk management",
        "terseLabel": "Derivative financial assets held for hedging",
        "label": "Derivative financial assets held for hedging"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of derivative financial assets held for hedging. [Refer: Derivative financial assets]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_DerivativeFinancialAssetsHeldForTrading": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DerivativeFinancialAssetsHeldForTrading",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails": {
       "parentTag": "ifrs-full_DerivativeFinancialAssets",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Derivative assets held for trading",
        "label": "Derivative financial assets held for trading"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of derivative financial assets held for trading. [Refer: Derivative financial assets; Financial assets at fair value through profit or loss, classified as held for trading]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_DerivativeFinancialAssetsPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DerivativeFinancialAssetsPercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Derivative financial instruments, percentage",
        "label": "Derivative Financial Assets, Percentage",
        "documentation": "The amount of financial assets classified as derivative instruments, expressed as a percentage."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DerivativeFinancialLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DerivativeFinancialLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails": {
       "parentTag": "ifrs-full_FinancialLiabilitiesAtFairValue",
       "weight": 1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialLiabilities",
       "weight": 1.0,
       "order": 5.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 9.0
      },
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      },
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Derivative financial instruments",
        "negatedTotalLabel": "Derivative liabilities",
        "negatedTerseLabel": "Derivative financial liabilities",
        "label": "Derivative financial liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial liabilities classified as derivative instruments. [Refer: Financial assets; Derivatives [member]]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_DerivativeFinancialLiabilitiesAndRepurchaseAgreementsAndCashCollateralOnSecuritiesLent": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DerivativeFinancialLiabilitiesAndRepurchaseAgreementsAndCashCollateralOnSecuritiesLent",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTotalLabel": "Total liabilities",
        "label": "Derivative Financial Liabilities And Repurchase Agreements And Cash Collateral On Securities Lent",
        "documentation": "Derivative Financial Liabilities And Repurchase Agreements And Cash Collateral On Securities Lent"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DerivativeFinancialLiabilitiesHeldForHedging": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DerivativeFinancialLiabilitiesHeldForHedging",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails": {
       "parentTag": "ifrs-full_DerivativeFinancialLiabilities",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Derivative liabilities held for risk management",
        "label": "Derivative financial liabilities held for hedging"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of derivative financial liabilities held for hedging. [Refer: Derivative financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_DerivativeFinancialLiabilitiesHeldForTrading": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DerivativeFinancialLiabilitiesHeldForTrading",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails": {
       "parentTag": "ifrs-full_DerivativeFinancialLiabilities",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Derivative liabilities held for trading",
        "label": "Derivative financial liabilities held for trading"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of derivative financial liabilities held for trading. [Refer: Derivative financial liabilities; Financial liabilities at fair value through profit or loss that meet definition of held for trading]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_DerivativeFinancialLiabilitiesUndiscountedCashFlows": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DerivativeFinancialLiabilitiesUndiscountedCashFlows",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails": {
       "parentTag": "bbplc_TotalFinancialLiabilitiesUndiscounted",
       "weight": 1.0,
       "order": 9.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Derivative financial instruments, undiscounted",
        "label": "Derivative financial liabilities, undiscounted cash flows"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of contractual undiscounted cash flows in relation to derivative financial liabilities. [Refer: Derivative financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r299",
      "r519"
     ]
    },
    "bbplc_DerivativeTransactionsDuringPeriodRelatedPartyTransactions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DerivativeTransactionsDuringPeriodRelatedPartyTransactions",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Derivatives transacted",
        "label": "Derivative Transactions During Period Related Party Transactions",
        "documentation": "The amount of derivative transactions during the period for related party transactions."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DerivativesAmountContributedToFairValueOfPlanAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DerivativesAmountContributedToFairValueOfPlanAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails": {
       "parentTag": "ifrs-full_PlanAssetsAtFairValue",
       "weight": 1.0,
       "order": 6.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Derivatives",
        "label": "Derivatives, amount contributed to fair value of plan assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount derivatives contribute to the fair value of defined benefit plan assets. [Refer: Plan assets, at fair value; Defined benefit plans [domain]; Derivatives [member]]"
       }
      }
     },
     "auth_ref": [
      "r617"
     ]
    },
    "ifrs-full_DerivativesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DerivativesMember",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureoftransferredfinancialassetsandtheassociatedliabilitiesDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails",
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "netLabel": "Derivative financial instruments",
        "terseLabel": "Derivative financial instruments",
        "verboseLabel": "Net derivative financial instruments",
        "label": "Derivatives [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for financial instruments or other contracts within the scope of IFRS 9 with all three of the following characteristics: (a) Their value changes in response to the change in a specified interest rate, financial instrument price, commodity price, foreign exchange rate, index of prices or rates, credit rating or credit index, or other variable, provided in the case of a non-financial variable that the variable is not specific to a party to the contract (sometimes called the \u2018underlying\u2019); (b) They require no initial net investment or an initial net investment that is smaller than would be required for other types of contracts that would be expected to have a similar response to changes in market factors; (c) They are settled at a future date. [Refer: Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r640",
      "r650",
      "r671",
      "r691"
     ]
    },
    "bbplc_DerivativesNettingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DerivativesNettingMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net derivatives financial instruments",
        "label": "Derivatives, Netting [Member]",
        "documentation": "Derivatives, Netting"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DerivativesWhichHedgeTheNetInvestmentsHedges": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DerivativesWhichHedgeTheNetInvestmentsHedges",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails": {
       "parentTag": "bbplc_StructuralCurrencyExposureBeforeHedgingInstruments",
       "weight": -1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Derivatives which hedge the net investments",
        "label": "Derivatives Which Hedge The Net Investments, Hedges",
        "documentation": "The amount of hedges classified as derivatives which hedge the net investments."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DescriptionOfAccountingPolicyForBorrowingsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForBorrowingsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for subordinated liabilities",
        "label": "Description of accounting policy for borrowings [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for borrowings. [Refer: Borrowings]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForCashFlowsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForCashFlowsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash flow statement",
        "label": "Description of accounting policy for cash flows [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for cash flows."
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForCollateralExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForCollateralExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for assets pledged, collateral received and assets transferred",
        "label": "Description of accounting policy for collateral [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for collateral."
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForContingentLiabilitiesAndContingentAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForContingentLiabilitiesAndContingentAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for contingent liabilities",
        "label": "Description of accounting policy for contingent liabilities and contingent assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for contingent liabilities and contingent assets. [Refer: Classes of contingent liabilities [domain]; Description of nature of contingent assets]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForDerecognitionOfFinancialInstrumentsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForDerecognitionOfFinancialInstrumentsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for securitisations",
        "label": "Description of accounting policy for derecognition of financial instruments [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for the derecognition of financial instruments. [Refer: Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForDerivativeFinancialInstrumentsAndHedgingExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForDerivativeFinancialInstrumentsAndHedgingExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for derivatives",
        "label": "Description of accounting policy for derivative financial instruments and hedging [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for derivative financial instruments and hedging. [Refer: Classes of financial instruments [domain]; Derivatives [member]]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForDividendsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForDividendsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for net investment (expense)/income",
        "label": "Description of accounting policy for dividends [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for dividends. Dividends are distributions of profits to holders of equity investments in proportion to their holdings of a particular class of capital."
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForEmployeeBenefitsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForEmployeeBenefitsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for staff costs, pensions and post-retirement benefits",
        "label": "Description of accounting policy for employee benefits [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for employee benefits. Employee benefits are all forms of consideration given by an entity in exchange for services rendered by employees or for the termination of employment."
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForFairValueMeasurementExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForFairValueMeasurementExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for financial assets and liabilities - fair values",
        "label": "Description of accounting policy for fair value measurement [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for fair value measurement. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForFeeAndCommissionIncomeAndExpenseExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForFeeAndCommissionIncomeAndExpenseExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for net fee and commission income",
        "label": "Description of accounting policy for fee and commission income and expense [text block]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForFinancialAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForFinancialAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for financial assets at fair value through other comprehensive income",
        "label": "Description of accounting policy for financial assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for financial assets. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForFinancialGuaranteesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForFinancialGuaranteesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for purchased financial guarantee contracts",
        "label": "Description of accounting policy for financial guarantees [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for financial guarantees. [Refer: Guarantees [member]]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForFinancialInstrumentsAtFairValueThroughProfitOrLossExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForFinancialInstrumentsAtFairValueThroughProfitOrLossExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for financial instruments at fair value",
        "label": "Description of accounting policy for financial instruments at fair value through profit or loss [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for financial instruments at fair value through profit or loss. [Refer: At fair value [member]; Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForFinancialInstrumentsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForFinancialInstrumentsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets and liabilities",
        "label": "Description of accounting policy for financial instruments [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for financial instruments. [Refer: Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForFinancialLiabilitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForFinancialLiabilitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for financial liabilities at fair value through profit and loss",
        "label": "Description of accounting policy for financial liabilities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for financial liabilities. [Refer: Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForForeignCurrencyTranslationExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForForeignCurrencyTranslationExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Foreign currency translation",
        "label": "Description of accounting policy for foreign currency translation [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for foreign currency translation."
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForHedgingExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForHedgingExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for hedging",
        "label": "Description of accounting policy for hedging [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for hedging."
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForImpairmentOfFinancialAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForImpairmentOfFinancialAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for the impairment of financial assets",
        "label": "Description of accounting policy for impairment of financial assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for the impairment of financial assets. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForIncomeTaxExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForIncomeTaxExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for income taxes",
        "label": "Description of accounting policy for income tax [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for income tax."
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForIntangibleAssetsAndGoodwillExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForIntangibleAssetsAndGoodwillExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for goodwill and intangible assets",
        "label": "Description of accounting policy for intangible assets and goodwill [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for intangible assets and goodwill. [Refer: Intangible assets and goodwill]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForInterestIncomeAndExpenseExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForInterestIncomeAndExpenseExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for interest income and expenses",
        "label": "Description of accounting policy for interest income and expense [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for income and expense arising from interest."
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForIssuedCapitalExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForIssuedCapitalExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Issued debt and equity instruments",
        "label": "Description of accounting policy for issued capital [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for issued capital. [Refer: Issued capital]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForLeasesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForLeasesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for leases",
        "label": "Description of accounting policy for leases [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for leases. A lease is an agreement whereby the lessor conveys to the lessee in return for a payment or series of payments the right to use an asset for an agreed period of time."
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "bbplc_DescriptionOfAccountingPolicyForNewAndAmendedStandardsAndInterpretationsPolicyTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DescriptionOfAccountingPolicyForNewAndAmendedStandardsAndInterpretationsPolicyTextBlock",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "New and amended standards and interpretations",
        "label": "Description Of Accounting Policy For New And Amended Standards And Interpretations [Policy Text Block]",
        "documentation": "Description Of Accounting Policy For New And Amended Standards And Interpretations"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DescriptionOfAccountingPolicyForNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for non-current assets held for sale and associated liabilities",
        "label": "Description of accounting policy for non-current assets or disposal groups classified as held for sale [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for non-current assets or disposal groups classified as held for sale. [Refer: Non-current assets or disposal groups classified as held for sale]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForOffsettingOfFinancialInstrumentsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForOffsettingOfFinancialInstrumentsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for offsetting financial assets and financial liabilities",
        "label": "Description of accounting policy for offsetting of financial instruments [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for the offsetting of financial instruments. [Refer: Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForPropertyPlantAndEquipmentExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForPropertyPlantAndEquipmentExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for property, plant and equipment",
        "label": "Description of accounting policy for property, plant and equipment [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for property, plant and equipment. [Refer: Property, plant and equipment]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForProvisionsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForProvisionsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for provisions",
        "label": "Description of accounting policy for provisions [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for provisions. [Refer: Provisions]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForRepurchaseAndReverseRepurchaseAgreementsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForRepurchaseAndReverseRepurchaseAgreementsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for reverse repurchase and repurchase agreements including other similar lending and borrowing",
        "label": "Description of accounting policy for repurchase and reverse repurchase agreements [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for repurchase and reverse repurchase agreements."
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForSegmentReportingExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForSegmentReportingExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for segmental reporting",
        "label": "Description of accounting policy for segment reporting [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for segment reporting."
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForSharebasedPaymentTransactionsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForSharebasedPaymentTransactionsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for Share-based payments",
        "label": "Description of accounting policy for share-based payment transactions [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for transactions in which the entity: (a) receives goods or services from the supplier of those goods or services (including an employee) in a share-based payment arrangement; or (b) incurs an obligation to settle the transaction with the supplier in a share-based payment arrangement when another group entity receives those goods or services. [Refer: Types of share-based payment arrangements [domain]]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForSubsidiariesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForSubsidiariesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for investment in subsidiaries",
        "label": "Description of accounting policy for subsidiaries [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The description of the entity's material accounting policy information for subsidiaries. [Refer: Total for all subsidiaries [member]]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "ifrs-full_DescriptionOfAccountingPolicyForTradingIncomeAndExpenseExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfAccountingPolicyForTradingIncomeAndExpenseExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for net trading income",
        "label": "Description of accounting policy for trading income and expense [text block]"
       }
      }
     },
     "auth_ref": [
      "r881"
     ]
    },
    "bbplc_DescriptionOfAccountingPolicyForTradingPortfolioAssetsAndLiabilitiesPolicyTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DescriptionOfAccountingPolicyForTradingPortfolioAssetsAndLiabilitiesPolicyTextBlock",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Accounting for trading portfolio assets and liabilities",
        "label": "Description Of Accounting Policy For Trading Portfolio Assets And Liabilities [Policy Text Block]",
        "documentation": "The description of the entity's accounting policy for trading portfolio assets and liabilities."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DescriptionOfDiscountRatesUsedInCurrentEstimateOfValueInUse": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfDiscountRatesUsedInCurrentEstimateOfValueInUse",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Discount rate",
        "label": "Discount rate used in current estimate of value in use"
       }
      },
      "en": {
       "role": {
        "documentation": "The discount rate used in the current estimate of the present value of the future cash flows expected to be derived from an asset or cash-generating unit."
       }
      }
     },
     "auth_ref": [
      "r78"
     ]
    },
    "ifrs-full_DescriptionOfExpectedVolatilityShareOptionsGranted": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfExpectedVolatilityShareOptionsGranted",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Expected volatility",
        "label": "Expected volatility, share options granted"
       }
      },
      "en": {
       "role": {
        "documentation": "The expected volatility of the share price used to calculate the fair value of the share options granted. Expected volatility is a measure of the amount by which a price is expected to fluctuate during a period. The measure of volatility used in option pricing models is the annualised standard deviation of the continuously compounded rates of return on the share over a period of time."
       }
      }
     },
     "auth_ref": [
      "r224"
     ]
    },
    "ifrs-full_DescriptionOfGrowthRateUsedToExtrapolateCashFlowProjections": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfGrowthRateUsedToExtrapolateCashFlowProjections",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Growth rate",
        "label": "Growth rate used to extrapolate cash flow projections"
       }
      },
      "en": {
       "role": {
        "documentation": "The growth rate used to extrapolate cash flow projections beyond the period covered by the most recent budgets/forecasts for a cash-generating unit (group of units). [Refer: Total for all cash-generating units [member]]"
       }
      }
     },
     "auth_ref": [
      "r81",
      "r83",
      "r436",
      "r438"
     ]
    },
    "ifrs-full_DescriptionOfOptionLifeShareOptionsGranted": {
     "xbrltype": "decimalItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfOptionLifeShareOptionsGranted",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Contractual life",
        "label": "Option life, share options granted"
       }
      },
      "en": {
       "role": {
        "documentation": "The option life of share options granted."
       }
      }
     },
     "auth_ref": [
      "r224"
     ]
    },
    "ifrs-full_DescriptionOfRiskFreeInterestRateShareOptionsGranted": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DescriptionOfRiskFreeInterestRateShareOptionsGranted",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Risk free interest rates",
        "label": "Risk free interest rate, share options granted"
       }
      },
      "en": {
       "role": {
        "documentation": "The implied yield currently available on zero-coupon government issues of the country in whose currency the exercise price for share options granted is expressed, with a remaining term equal to the expected term of the option being valued (based on the option's remaining contractual life and taking into account the effects of expected early exercise). [Refer: Government [member]]"
       }
      }
     },
     "auth_ref": [
      "r224"
     ]
    },
    "ifrs-full_DesignatedFinancialLiabilitiesAtFairValueThroughProfitOrLossAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DesignatedFinancialLiabilitiesAtFairValueThroughProfitOrLossAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Designated financial liabilities at fair value through profit or loss [abstract]",
        "label": "Designated financial liabilities at fair value through profit or loss [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DetailedInformationAboutInvestmentsInAssociatesAndJointVenturesTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DetailedInformationAboutInvestmentsInAssociatesAndJointVenturesTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of investments in associates and joint ventures",
        "label": "Detailed Information About Investments In Associates And Joint Ventures [Table Text Block]",
        "documentation": "The disclosure of detailed information about investments in associates and joint ventures."
       }
      }
     },
     "auth_ref": []
    },
    "srt_DirectorMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "DirectorMember",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Director",
        "label": "Director [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DirectorsExpenseCompaniesAct2006": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DirectorsExpenseCompaniesAct2006",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total directors expense in accordance with companies act 2006",
        "label": "Directors Expense Companies Act 2006",
        "documentation": "The amount of directors expenses is presented in accordance with the companies act 2006."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfAccountingJudgementsAndEstimatesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfAccountingJudgementsAndEstimatesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Critical accounting estimates and judgements",
        "label": "Disclosure of accounting judgements and estimates [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of judgements that management has made in the process of applying the entity's accounting policies that have the most significant effect on amounts recognised in the financial statements along with information about the assumptions that the entity makes about the future, and other major sources of estimation uncertainty at the end of the reporting period, that have a significant risk of resulting in a material adjustment to the carrying amounts of assets and liabilities within the next year. [Refer: Carrying amount [member]]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfAccruedExpensesAndOtherLiabilitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfAccruedExpensesAndOtherLiabilitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Otherliabilities"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other liabilities",
        "label": "Disclosure of accrued expenses and other liabilities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of accrued expenses and other liabilities. [Refer: Accruals; Other liabilities]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfAdditionalInformationAboutLeasingActivitiesForLesseeExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfAdditionalInformationAboutLeasingActivitiesForLesseeExplanatory",
     "presentation": [
      "http://www.home.barclays/role/LeasesTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of lease liabilities and maturity analysis",
        "label": "Disclosure of additional information about leasing activities for lessee [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of additional information about leasing activities of a lessee."
       }
      }
     },
     "auth_ref": [
      "r195",
      "r368"
     ]
    },
    "ifrs-full_DisclosureOfAdditionalInformationExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfAdditionalInformationExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of management adjustments to models for impairment and Economic uncertainty management adjustments to models for impairment",
        "label": "Disclosure of additional information [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of additional information that is not presented elsewhere in the financial statements, but that is relevant to an understanding of them."
       }
      }
     },
     "auth_ref": [
      "r377",
      "r557"
     ]
    },
    "ifrs-full_DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of remuneration of Directors and other Key Management Personnel",
        "label": "Disclosure of amounts incurred by entity for provision of key management personnel services provided by separate management entities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of amounts incurred by the entity for provision of key management personnel services that are provided by separate management entities. [Refer: Key management personnel of entity or parent [member]; Separate management entities [domain]]"
       }
      }
     },
     "auth_ref": [
      "r52",
      "r420"
     ]
    },
    "bbplc_DisclosureOfAnalysisOfCreditExposuresUsingAnExternalCreditGradingSystemTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfAnalysisOfCreditExposuresUsingAnExternalCreditGradingSystemTextBlock",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of macroeconomic variables used in the calculation of ECL and Scenario probability weighting",
        "label": "Disclosure Of Analysis Of Credit Exposures Using An External Credit Grading System [Text Block]",
        "documentation": "Disclosure Of Analysis Of Credit Exposures Using An External Credit Grading System"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DisclosureOfAnalysisOfCreditRiskProfileContingentLiabilitiesAndLoanCommitmentsTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfAnalysisOfCreditRiskProfileContingentLiabilitiesAndLoanCommitmentsTextBlock",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of analysis of credit risk profile by internal PD band for loans and advances at amortised cost, contingent liabilities and loan commitments",
        "label": "Disclosure Of Analysis Of Credit Risk Profile, Contingent Liabilities And Loan Commitments [Text Block]",
        "documentation": "Disclosure Of Analysis Of Credit Risk Profile, Contingent Liabilities And Loan Commitments"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfAnalysisOfOtherComprehensiveIncomeByItemExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfAnalysisOfOtherComprehensiveIncomeByItemExplanatory",
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughothercomprehensiveincomeTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of detailed information about financial assets at fair value through other comprehensive income",
        "label": "Disclosure of analysis of other comprehensive income by item [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure of the analysis of other comprehensive income by item."
       }
      }
     },
     "auth_ref": [
      "r556"
     ]
    },
    "bbplc_DisclosureOfAssetsAndLiabilitiesClassifiedAsHeldForSaleLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfAssetsAndLiabilitiesClassifiedAsHeldForSaleLineItems",
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure Of Assets And Liabilities Classified As Held For Sale [Line Items]",
        "label": "Disclosure Of Assets And Liabilities Classified As Held For Sale [Line Items]",
        "documentation": "Disclosure Of Assets And Liabilities Classified As Held For Sale [Line Items]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DisclosureOfAssetsAndLiabilitiesClassifiedAsHeldForSaleTable": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfAssetsAndLiabilitiesClassifiedAsHeldForSaleTable",
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure Of Assets And Liabilities Classified As Held For Sale [Table]",
        "label": "Disclosure Of Assets And Liabilities Classified As Held For Sale [Table]",
        "documentation": "Disclosure Of Assets And Liabilities Classified As Held For Sale [Table]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DisclosureOfAssetsAndLiabilitiesClassifiedAsHeldForSaleTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfAssetsAndLiabilitiesClassifiedAsHeldForSaleTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleTables",
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Disclosure of loans and advances to customers classified as assets held for sale",
        "terseLabel": "Disclosure of assets and liabilities classified as held for sale",
        "label": "Disclosure Of Assets And Liabilities Classified As Held For Sale [Table Text Block]",
        "documentation": "The disclosure of assets and liabilities classified as held for sale."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfAuditorsRemunerationExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfAuditorsRemunerationExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Auditorsremuneration"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Auditor's remuneration",
        "label": "Disclosure of auditors' remuneration [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of compensation to the entity's auditors."
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfBasisOfConsolidationExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfBasisOfConsolidationExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Consolidation",
        "label": "Disclosure of basis of consolidation [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the basis used for consolidation."
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfBasisOfPreparationOfFinancialStatementsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfBasisOfPreparationOfFinancialStatementsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Basis of preparation",
        "label": "Disclosure of basis of preparation of financial statements [text block]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "bbplc_DisclosureOfCarryingAmountOfTheAssetsPledgedAndAssetsTransferredAsSecurityAgainstLiabilitiesTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfCarryingAmountOfTheAssetsPledgedAndAssetsTransferredAsSecurityAgainstLiabilitiesTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of assets pledged and assets transferred as security against liabilities",
        "label": "Disclosure Of Carrying Amount Of The Assets Pledged And Assets Transferred As Security Against Liabilities [Table Text Block]",
        "documentation": "The tabular disclosure of assets pledged and assets transferred as security against liabilities."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfClassesOfShareCapitalExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfClassesOfShareCapitalExplanatory",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of called up share capital, allotted and fully paid",
        "label": "Disclosure of classes of share capital [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of classes of share capital. [Refer: Classes of share capital [domain]]"
       }
      }
     },
     "auth_ref": [
      "r380",
      "r537",
      "r584"
     ]
    },
    "ifrs-full_DisclosureOfCollateralExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfCollateralExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Assetspledgedcollateralreceivedandassetstransferred"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets pledged, collateral received and assets transferred",
        "label": "Disclosure of collateral [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of assets and liabilities used as collateral."
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfCommitmentsAndContingentLiabilitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfCommitmentsAndContingentLiabilitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Contingentliabilitiesandcommitments"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Contingent liabilities and commitments",
        "label": "Disclosure of commitments and contingent liabilities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of commitments and contingent liabilities. [Refer: Classes of contingent liabilities [domain]]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "bbplc_DisclosureOfCommitmentsAndContingentLiabilitiesTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfCommitmentsAndContingentLiabilitiesTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Summary of contingent liabilities and commitments",
        "label": "Disclosure Of Commitments And Contingent Liabilities [Table Text Block]",
        "documentation": "The tabular disclosure of commitments and contingent liabilities of the entity."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfCommitmentsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfCommitmentsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Legalcompetitionandregulatorymatters"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Legal, competition and regulatory matters",
        "label": "Disclosure of commitments [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of commitments."
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "bbplc_DisclosureOfComponentsOfIncomeTaxTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfComponentsOfIncomeTaxTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/TaxTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of components of income tax",
        "label": "Disclosure Of Components Of Income Tax [Table Text Block]",
        "documentation": "The tabular disclosure of major components of income tax expense (income)."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfContingentLiabilitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfContingentLiabilitiesAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of contingent liabilities [abstract]",
        "label": "Disclosure of contingent liabilities [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfContingentLiabilitiesLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfContingentLiabilitiesLineItems",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsNarrativeDetails",
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails",
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of contingent liabilities [line items]",
        "label": "Disclosure of contingent liabilities [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfContingentLiabilitiesTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfContingentLiabilitiesTable",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsNarrativeDetails",
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails",
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of contingent liabilities [table]",
        "label": "Disclosure of contingent liabilities [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to contingent liabilities."
       }
      }
     },
     "auth_ref": [
      "r98",
      "r448"
     ]
    },
    "ifrs-full_DisclosureOfContinuingInvolvementInDerecognisedFinancialAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfContinuingInvolvementInDerecognisedFinancialAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of continuing involvement in financial assets that have been derecognised",
        "label": "Disclosure of continuing involvement in derecognised financial assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of continuing involvement in derecognised financial assets. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r308",
      "r311"
     ]
    },
    "ifrs-full_DisclosureOfContinuingInvolvementInDerecognisedFinancialAssetsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfContinuingInvolvementInDerecognisedFinancialAssetsLineItems",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureofcontinuinginvolvementinfinancialassetsthathavebeenderecognisedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of continuing involvement in derecognised financial assets [line items]",
        "label": "Disclosure of continuing involvement in derecognised financial assets [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfContinuingInvolvementInDerecognisedFinancialAssetsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfContinuingInvolvementInDerecognisedFinancialAssetsTable",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureofcontinuinginvolvementinfinancialassetsthathavebeenderecognisedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of continuing involvement in derecognised financial assets [table]",
        "label": "Disclosure of continuing involvement in derecognised financial assets [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to continuing involvement in derecognised financial assets."
       }
      }
     },
     "auth_ref": [
      "r308",
      "r311"
     ]
    },
    "bbplc_DisclosureOfCreditQualityOfAssetsExposedToCreditRiskTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfCreditQualityOfAssetsExposedToCreditRiskTextBlock",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of Balance Sheet credit quality",
        "label": "Disclosure of Credit Quality of Assets Exposed to Credit Risk [Text Block]",
        "documentation": "Disclosure of Credit Quality of Assets Exposed to Credit Risk"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfCreditRiskExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfCreditRiskExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of movement in gross exposure and impairment allowance including provisions for loan commitments and financial guarantees",
        "label": "Disclosure of credit risk [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of credit risk. [Refer: Credit risk [member]]"
       }
      }
     },
     "auth_ref": [
      "r327",
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfCreditRiskExposureAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfCreditRiskExposureAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of credit risk exposure [abstract]",
        "label": "Disclosure of credit risk exposure [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfCreditRiskExposureExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfCreditRiskExposureExplanatory",
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of credit risk of loans and advances designated at fair value and related credit derivatives",
        "label": "Disclosure of credit risk exposure [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the credit risk exposure. Credit risk exposure is the credit risk inherent in an entity\u2019s financial assets and commitments to extend credit."
       }
      }
     },
     "auth_ref": [
      "r296",
      "r517"
     ]
    },
    "ifrs-full_DisclosureOfDeferredTaxesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDeferredTaxesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/TaxTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of deferred tax assets and liabilities",
        "label": "Disclosure of deferred taxes [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of deferred taxes. [Refer: Deferred tax liabilities; Deferred tax assets]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfDefinedBenefitPlansAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDefinedBenefitPlansAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of defined benefit plans [abstract]",
        "label": "Disclosure of defined benefit plans [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfDerivativeFinancialInstrumentsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDerivativeFinancialInstrumentsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Derivativefinancialinstruments"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Derivative financial instruments",
        "label": "Disclosure of derivative financial instruments [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of derivative financial instruments. [Refer: Derivatives [member]]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "bbplc_DisclosureOfDetailedInformationAboutAuditorsRemunerationTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfDetailedInformationAboutAuditorsRemunerationTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of Auditor's remuneration",
        "label": "Disclosure Of Detailed Information About Auditors' Remuneration [Table Text Block]",
        "documentation": "The disclosure of detailed information about compensation to the entity's auditors."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDetailedInformationAboutBorrowingsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of subordinated liabilities",
        "label": "Disclosure of detailed information about borrowings [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of detailed information about borrowings. [Refer: Borrowings]"
       }
      }
     },
     "auth_ref": [
      "r875"
     ]
    },
    "ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDetailedInformationAboutBorrowingsLineItems",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of detailed information about borrowings [line items]",
        "label": "Disclosure of detailed information about borrowings [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDetailedInformationAboutBorrowingsTable",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of detailed information about borrowings [table]",
        "label": "Disclosure of detailed information about borrowings [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to details of borrowings."
       }
      }
     },
     "auth_ref": [
      "r875"
     ]
    },
    "ifrs-full_DisclosureOfDetailedInformationAboutHedgedItemsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDetailedInformationAboutHedgedItemsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of hedged items in fair value hedges and hedged items in cash flow hedges and hedges of net investments in foreign operations",
        "label": "Disclosure of detailed information about hedged items [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of detailed information about hedged items. [Refer: Hedged items [domain]]"
       }
      }
     },
     "auth_ref": [
      "r267",
      "r499"
     ]
    },
    "ifrs-full_DisclosureOfDetailedInformationAboutHedgedItemsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDetailedInformationAboutHedgedItemsLineItems",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of detailed information about hedged items [line items]",
        "label": "Disclosure of detailed information about hedged items [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfDetailedInformationAboutHedgedItemsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDetailedInformationAboutHedgedItemsTable",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of detailed information about hedged items [table]",
        "label": "Disclosure of detailed information about hedged items [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to details of hedged items."
       }
      }
     },
     "auth_ref": [
      "r267",
      "r499"
     ]
    },
    "ifrs-full_DisclosureOfDetailedInformationAboutHedgingInstrumentsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDetailedInformationAboutHedgingInstrumentsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of hedging instruments which are carried on the Group's balance sheet",
        "label": "Disclosure of detailed information about hedging instruments [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of detailed information about hedging instruments. [Refer: Hedging instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r259",
      "r494",
      "r506"
     ]
    },
    "ifrs-full_DisclosureOfDetailedInformationAboutHedgingInstrumentsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDetailedInformationAboutHedgingInstrumentsLineItems",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of detailed information about hedging instruments [line items]",
        "label": "Disclosure of detailed information about hedging instruments [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfDetailedInformationAboutHedgingInstrumentsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDetailedInformationAboutHedgingInstrumentsTable",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of detailed information about hedging instruments [table]",
        "label": "Disclosure of detailed information about hedging instruments [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to details of hedging instruments."
       }
      }
     },
     "auth_ref": [
      "r259",
      "r494"
     ]
    },
    "ifrs-full_DisclosureOfDetailedInformationAboutIntangibleAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDetailedInformationAboutIntangibleAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of amortisation periods for goodwill and intangible assets",
        "label": "Disclosure of detailed information about intangible assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of detailed information about intangible assets. [Refer: Intangible assets other than goodwill]"
       }
      }
     },
     "auth_ref": [
      "r104",
      "r453"
     ]
    },
    "ifrs-full_DisclosureOfDetailedInformationAboutPropertyPlantAndEquipmentExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDetailedInformationAboutPropertyPlantAndEquipmentExplanatory",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of depreciation rates",
        "label": "Disclosure of detailed information about property, plant and equipment [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of detailed information about property, plant and equipment. [Refer: Property, plant and equipment]"
       }
      }
     },
     "auth_ref": [
      "r16",
      "r402"
     ]
    },
    "ifrs-full_DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersExplanatory",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Summary of total fees in scope of IFRS 15 Revenues from Contracts with Customers",
        "label": "Disclosure of disaggregation of revenue from contracts with customers [text block]"
       }
      }
     },
     "auth_ref": [
      "r181",
      "r356"
     ]
    },
    "ifrs-full_DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of disaggregation of revenue from contracts with customers [line items]",
        "label": "Disclosure of disaggregation of revenue from contracts with customers [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of disaggregation of revenue from contracts with customers [table]",
        "label": "Disclosure of disaggregation of revenue from contracts with customers [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the disaggregation of revenue from contracts with customers."
       }
      }
     },
     "auth_ref": [
      "r181",
      "r356"
     ]
    },
    "bbplc_DisclosureOfDisposalOfBusinessesAndDiscontinuedOperationsTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfDisposalOfBusinessesAndDiscontinuedOperationsTextBlock",
     "presentation": [
      "http://www.home.barclays/role/AcquisitionandDisposalsofsubsidiaries"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Acquisition and Disposals of subsidiaries",
        "label": "Disclosure Of Disposal Of Businesses And Discontinued Operations [Text Block]",
        "documentation": "The entire disclosure on the disposal of business and discontinued operations."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfDividendsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfDividendsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Dividendsonordinarysharesandpreferenceshares"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Dividends on ordinary shares and preference shares",
        "label": "Disclosure of dividends [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of dividends. Dividends are distributions of profits to holders of equity investments in proportion to their holdings of a particular class of capital."
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfEffectOfChangesInForeignExchangeRatesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfEffectOfChangesInForeignExchangeRatesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of functional currency of the operation",
        "label": "Disclosure of effect of changes in foreign exchange rates [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure for the effect of changes in foreign exchange rates."
       }
      }
     },
     "auth_ref": [
      "r44"
     ]
    },
    "ifrs-full_DisclosureOfEmployeeBenefitsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfEmployeeBenefitsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Retirementbenefits"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Retirement benefits",
        "label": "Disclosure of employee benefits [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure for employee benefits."
       }
      }
     },
     "auth_ref": [
      "r39"
     ]
    },
    "ifrs-full_DisclosureOfEntitysReportableSegmentsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfEntitysReportableSegmentsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Segmentalreporting"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Segmental reporting",
        "label": "Disclosure of entity's operating segments [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure for operating segments."
       }
      }
     },
     "auth_ref": [
      "r346"
     ]
    },
    "ifrs-full_DisclosureOfExpensesByNatureExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfExpensesByNatureExplanatory",
     "presentation": [
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of infrastructure, administration and general expenses",
        "label": "Disclosure of expenses by nature [text block]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfExpensesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfExpensesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Infrastructureadministrationandgeneralexpenses"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Infrastructure, administration and general expenses",
        "label": "Disclosure of expenses [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of expenses."
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "bbplc_DisclosureOfFairValueAdjustmentsTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfFairValueAdjustmentsTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of fair value adjustments",
        "label": "Disclosure Of Fair Value Adjustments [Table Text Block]",
        "documentation": "The tabular disclosure of key balance sheet valuation adjustments."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfFairValueMeasurementExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFairValueMeasurementExplanatory",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of assets and liabilities held at fair value, disaggregated by valuation technique and by product type",
        "label": "Disclosure of fair value measurement [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure for fair value measurement."
       }
      }
     },
     "auth_ref": [
      "r176"
     ]
    },
    "ifrs-full_DisclosureOfFairValueMeasurementOfAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFairValueMeasurementOfAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of Level 3 assets",
        "label": "Disclosure of fair value measurement of assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the fair value measurement of assets."
       }
      }
     },
     "auth_ref": [
      "r173",
      "r534"
     ]
    },
    "ifrs-full_DisclosureOfFairValueMeasurementOfLiabilitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFairValueMeasurementOfLiabilitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of Level 3 liabilities",
        "label": "Disclosure of fair value measurement of liabilities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the fair value measurement of liabilities."
       }
      }
     },
     "auth_ref": [
      "r173",
      "r534"
     ]
    },
    "ifrs-full_DisclosureOfFairValueOfFinancialInstrumentsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFairValueOfFinancialInstrumentsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Fairvalueoffinancialinstruments"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fair value of financial instruments",
        "label": "Disclosure of fair value of financial instruments [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the fair value of financial instruments. [Refer: Classes of financial instruments [domain]; At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfFairValueOfPlanAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFairValueOfPlanAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of analysis of scheme assets",
        "label": "Disclosure of fair value of plan assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the fair value of defined benefit plan assets. [Refer: Plan assets [member]; Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r33",
      "r414"
     ]
    },
    "ifrs-full_DisclosureOfFairValueOfPlanAssetsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFairValueOfPlanAssetsLineItems",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of fair value of plan assets [line items]",
        "label": "Disclosure of fair value of plan assets [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfFairValueOfPlanAssetsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFairValueOfPlanAssetsTable",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of fair value of plan assets [table]",
        "label": "Disclosure of fair value of plan assets [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the fair value of defined benefit plan assets."
       }
      }
     },
     "auth_ref": [
      "r33",
      "r414"
     ]
    },
    "ifrs-full_DisclosureOfFeeAndCommissionIncomeExpenseExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFeeAndCommissionIncomeExpenseExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Netfeeandcommissionincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net fee and commission income",
        "label": "Disclosure of fee and commission income (expense) [text block]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfFinanceIncomeExpenseExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinanceIncomeExpenseExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Netinvestmentexpenseincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net investment (expense)/income",
        "label": "Disclosure of finance income (cost) [text block]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfFinancialAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Financialassetsatfairvaluethroughothercomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets at fair value through other comprehensive income",
        "label": "Disclosure of financial assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of financial assets. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r314",
      "r474"
     ]
    },
    "ifrs-full_DisclosureOfFinancialAssetsHeldForTradingExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialAssetsHeldForTradingExplanatory",
     "presentation": [
      "http://www.home.barclays/role/TradingportfolioTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of trading portfolio assets",
        "label": "Disclosure of financial assets held for trading [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of financial assets classified as held for trading. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfFinancialAssetsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialAssetsLineItems",
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughothercomprehensiveincomeDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of financial assets [line items]",
        "label": "Disclosure of financial assets [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfFinancialAssetsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialAssetsTable",
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughothercomprehensiveincomeDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of financial assets [table]",
        "label": "Disclosure of financial assets [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to financial assets."
       }
      }
     },
     "auth_ref": [
      "r314",
      "r474"
     ]
    },
    "ifrs-full_DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of transferred financial assets that are not derecognised in their entirety [abstract]",
        "label": "Disclosure of transferred financial assets that are not derecognised in their entirety [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionExplanatory",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of transfers of financial assets that do not result in derecognition",
        "label": "Disclosure of transferred financial assets that are not derecognised in their entirety [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of transferred financial assets that are not derecognised in their entirety. [Refer: Transferred financial assets that are not derecognised in their entirety [domain]]"
       }
      }
     },
     "auth_ref": [
      "r303",
      "r521"
     ]
    },
    "ifrs-full_DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionLineItems",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails",
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureoftransferredfinancialassetsandtheassociatedliabilitiesDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails",
      "http://www.home.barclays/role/SecuritisationsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of transferred financial assets that are not derecognised in their entirety [line items]",
        "label": "Disclosure of transferred financial assets that are not derecognised in their entirety [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialAssetsTransferredDuringPeriodWhichDoNotQualifyForDerecognitionTable",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails",
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureoftransferredfinancialassetsandtheassociatedliabilitiesDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails",
      "http://www.home.barclays/role/SecuritisationsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of transferred financial assets that are not derecognised in their entirety [table]",
        "label": "Disclosure of transferred financial assets that are not derecognised in their entirety [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to transferred financial assets that are not derecognised in their entirety."
       }
      }
     },
     "auth_ref": [
      "r303",
      "r521"
     ]
    },
    "ifrs-full_DisclosureOfFinancialInstrumentsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialInstrumentsAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of detailed information about financial instruments [abstract]",
        "label": "Disclosure of detailed information about financial instruments [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfFinancialInstrumentsAtFairValueThroughProfitOrLossExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialInstrumentsAtFairValueThroughProfitOrLossExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Financialassetsatfairvaluethroughtheincomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets at fair value through the income statement",
        "label": "Disclosure of financial instruments at fair value through profit or loss [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of financial instruments measured at fair value through profit or loss. [Refer: At fair value [member]; Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfFinancialInstrumentsDesignatedAtFairValueThroughProfitOrLossExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialInstrumentsDesignatedAtFairValueThroughProfitOrLossExplanatory",
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementTables",
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of financial assets designated at fair value",
        "verboseLabel": "Disclosure of financial liabilities designated at fair value",
        "label": "Disclosure of financial instruments designated at fair value through profit or loss [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of financial instruments designated at fair value through profit or loss. [Refer: At fair value [member]; Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfFinancialInstrumentsHeldForTradingExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialInstrumentsHeldForTradingExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Tradingportfolio"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Trading portfolio",
        "label": "Disclosure of financial instruments held for trading [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of financial instruments classified as held for trading. [Refer: Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfFinancialInstrumentsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialInstrumentsLineItems",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureoffairvalueadjustmentsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails",
      "http://www.home.barclays/role/NettradingincomeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/TradingportfolioDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of detailed information about financial instruments [line items]",
        "label": "Disclosure of detailed information about financial instruments [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfFinancialInstrumentsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialInstrumentsTable",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureoffairvalueadjustmentsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails",
      "http://www.home.barclays/role/NettradingincomeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TradingportfolioDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of detailed information about financial instruments [table]",
        "label": "Disclosure of detailed information about financial instruments [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to details of financial instruments."
       }
      }
     },
     "auth_ref": [
      "r276",
      "r291",
      "r314",
      "r474"
     ]
    },
    "ifrs-full_DisclosureOfFinancialLiabilitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialLiabilitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Financialliabilitiesdesignatedatfairvalue"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial liabilities designated at fair value",
        "label": "Disclosure of financial liabilities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of financial liabilities. [Refer: Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r314",
      "r474"
     ]
    },
    "ifrs-full_DisclosureOfFinancialLiabilitiesHeldForTradingExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialLiabilitiesHeldForTradingExplanatory",
     "presentation": [
      "http://www.home.barclays/role/TradingportfolioTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of trading portfolio liabilities",
        "label": "Disclosure of financial liabilities held for trading [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of financial liabilities classified as held for trading. [Refer: Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfFinancialLiabilitiesLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialLiabilitiesLineItems",
     "presentation": [
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of financial liabilities [line items]",
        "label": "Disclosure of financial liabilities [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfFinancialLiabilitiesTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialLiabilitiesTable",
     "presentation": [
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of financial liabilities [table]",
        "label": "Disclosure of financial liabilities [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to financial liabilities."
       }
      }
     },
     "auth_ref": [
      "r314",
      "r474"
     ]
    },
    "ifrs-full_DisclosureOfFinancialRiskManagementExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfFinancialRiskManagementExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of capital resources",
        "label": "Disclosure of financial risk management [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the entity's financial risk management practices and policies."
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfGeographicalAreasExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfGeographicalAreasExplanatory",
     "presentation": [
      "http://www.home.barclays/role/SegmentalreportingTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of income by geographic region",
        "label": "Disclosure of geographical areas [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of geographical information."
       }
      }
     },
     "auth_ref": [
      "r345"
     ]
    },
    "ifrs-full_DisclosureOfGeographicalAreasLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfGeographicalAreasLineItems",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of geographical areas [line items]",
        "label": "Disclosure of geographical areas [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfGeographicalAreasTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfGeographicalAreasTable",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of geographical areas [table]",
        "label": "Disclosure of geographical areas [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to geographical areas."
       }
      }
     },
     "auth_ref": [
      "r345"
     ]
    },
    "ifrs-full_DisclosureOfGoodwillExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfGoodwillExplanatory",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of goodwill allocated to business operations according to business segments",
        "label": "Disclosure of goodwill [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of goodwill. [Refer: Goodwill]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "bbplc_DisclosureOfGroupsFinancialStatementsByCategoryTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfGroupsFinancialStatementsByCategoryTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of amounts included in the Group's financial statements by category",
        "label": "Disclosure Of Groups Financial Statements By Category [Table Text Block]",
        "documentation": "The disclosure of group's financial statement by category and related party."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfImpairmentLossAndReversalOfImpairmentLossAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfImpairmentLossAndReversalOfImpairmentLossAbstract",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation of ECL movement to impairment (charge)/release for the period, Loans and advances at amortised cost",
        "label": "Disclosure of impairment loss and reversal of impairment loss [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfImpairmentLossAndReversalOfImpairmentLossExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfImpairmentLossAndReversalOfImpairmentLossExplanatory",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of credit impairment charges/ (releases)",
        "label": "Disclosure of impairment loss and reversal of impairment loss [text block]"
       }
      }
     },
     "auth_ref": [
      "r72",
      "r434"
     ]
    },
    "ifrs-full_DisclosureOfImpairmentLossAndReversalOfImpairmentLossLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfImpairmentLossAndReversalOfImpairmentLossLineItems",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of impairment loss and reversal of impairment loss [line items]",
        "label": "Disclosure of impairment loss and reversal of impairment loss [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfImpairmentLossAndReversalOfImpairmentLossTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfImpairmentLossAndReversalOfImpairmentLossTable",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of impairment loss and reversal of impairment loss [table]",
        "label": "Disclosure of impairment loss and reversal of impairment loss [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to impairment loss and the reversal of impairment loss."
       }
      }
     },
     "auth_ref": [
      "r72",
      "r434"
     ]
    },
    "ifrs-full_DisclosureOfImpairmentLossRecognisedOrReversedTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfImpairmentLossRecognisedOrReversedTable",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of impairment loss recognised or reversed for cash-generating unit [table]",
        "label": "Disclosure of impairment loss recognised or reversed for cash-generating unit [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to impairment loss recognised or reversed for a cash-generating unit."
       }
      }
     },
     "auth_ref": [
      "r75"
     ]
    },
    "ifrs-full_DisclosureOfImpairmentOfAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfImpairmentOfAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Creditimpairmentchargesreleases"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Credit impairment charges/(releases)",
        "label": "Disclosure of impairment of assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure for the impairment of assets."
       }
      }
     },
     "auth_ref": [
      "r91"
     ]
    },
    "ifrs-full_DisclosureOfIncomeTaxExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfIncomeTaxExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Tax"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Tax",
        "label": "Disclosure of income tax [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure for income taxes."
       }
      }
     },
     "auth_ref": [
      "r12"
     ]
    },
    "ifrs-full_DisclosureOfInformationAboutAmountsThatAffectedStatementOfComprehensiveIncomeAsResultOfHedgeAccountingExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationAboutAmountsThatAffectedStatementOfComprehensiveIncomeAsResultOfHedgeAccountingExplanatory",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of effect on the income statement, OCI, and reserves as a result of hedge accounting",
        "label": "Disclosure of information about amounts that affected statement of comprehensive income as result of hedge accounting [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of information about amounts that affected the statement of comprehensive income as a result of hedge accounting."
       }
      }
     },
     "auth_ref": [
      "r271",
      "r503"
     ]
    },
    "ifrs-full_DisclosureOfInformationAboutAmountsThatAffectedStatementOfComprehensiveIncomeAsResultOfHedgeAccountingLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationAboutAmountsThatAffectedStatementOfComprehensiveIncomeAsResultOfHedgeAccountingLineItems",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of information about amounts that affected statement of comprehensive income as result of hedge accounting [line items]",
        "label": "Disclosure of information about amounts that affected statement of comprehensive income as result of hedge accounting [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfInformationAboutAmountsThatAffectedStatementOfComprehensiveIncomeAsResultOfHedgeAccountingTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationAboutAmountsThatAffectedStatementOfComprehensiveIncomeAsResultOfHedgeAccountingTable",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of information about amounts that affected statement of comprehensive income as result of hedge accounting [table]",
        "label": "Disclosure of information about amounts that affected statement of comprehensive income as result of hedge accounting [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to amounts that affected the statement of comprehensive income as a result of hedge accounting."
       }
      }
     },
     "auth_ref": [
      "r271",
      "r503"
     ]
    },
    "ifrs-full_DisclosureOfInformationAboutConsolidatedStructuredEntitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationAboutConsolidatedStructuredEntitiesAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of information about consolidated structured entities [abstract]",
        "label": "Disclosure of information about consolidated structured entities [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfInformationAboutConsolidatedStructuredEntitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationAboutConsolidatedStructuredEntitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of principal subsidiaries",
        "label": "Disclosure of information about consolidated structured entities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of information about consolidated structured entities. [Refer: Total for all consolidated structured entities [member]]"
       }
      }
     },
     "auth_ref": [
      "r161"
     ]
    },
    "ifrs-full_DisclosureOfInformationAboutInterestsInStructuredEntityExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationAboutInterestsInStructuredEntityExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Structuredentities"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Structured entities",
        "label": "Disclosure of information about interests in structured entity [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of qualitative and quantitative information about the entity's interests in structured entities, including, but not limited to, the nature, purpose, size and activities of the structured entity and how the structured entity is financed."
       }
      }
     },
     "auth_ref": [
      "r143"
     ]
    },
    "ifrs-full_DisclosureOfInformationAboutTermsAndConditionsOfHedgingInstrumentsAndHowTheyAffectFutureCashFlowsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationAboutTermsAndConditionsOfHedgingInstrumentsAndHowTheyAffectFutureCashFlowsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of expected notional values of current hedging instruments in future years",
        "label": "Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of information about the terms and conditions of hedging instruments and how they affect future cash flows. [Refer: Hedging instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r253",
      "r355"
     ]
    },
    "ifrs-full_DisclosureOfInformationAboutTermsAndConditionsOfHedgingInstrumentsAndHowTheyAffectFutureCashFlowsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationAboutTermsAndConditionsOfHedgingInstrumentsAndHowTheyAffectFutureCashFlowsLineItems",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]",
        "label": "Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfInformationAboutTermsAndConditionsOfHedgingInstrumentsAndHowTheyAffectFutureCashFlowsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationAboutTermsAndConditionsOfHedgingInstrumentsAndHowTheyAffectFutureCashFlowsTable",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [table]",
        "label": "Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the terms and conditions of hedging instruments and how they affect future cash flows."
       }
      }
     },
     "auth_ref": [
      "r253"
     ]
    },
    "ifrs-full_DisclosureOfInformationAboutUnconsolidatedStructuredEntitiesControlledByInvestmentEntityTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationAboutUnconsolidatedStructuredEntitiesControlledByInvestmentEntityTable",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails",
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of information about unconsolidated structured entities controlled by investment entity [table]",
        "label": "Disclosure of information about unconsolidated structured entities controlled by investment entity [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to unconsolidated structured entities controlled by the investment entity."
       }
      }
     },
     "auth_ref": [
      "r138",
      "r526"
     ]
    },
    "ifrs-full_DisclosureOfInformationForEachMaterialImpairmentLossRecognisedOrReversedForIndividualAssetOrCashgeneratingUnitLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationForEachMaterialImpairmentLossRecognisedOrReversedForIndividualAssetOrCashgeneratingUnitLineItems",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]",
        "label": "Disclosure of information for impairment loss recognised or reversed for individual asset or cash-generating unit [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of sensitivity of the value in use to key judgements in the calculations",
        "label": "Disclosure of information for cash-generating units [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of information for cash-generating units. [Refer: Total for all cash-generating units [member]]"
       }
      }
     },
     "auth_ref": [
      "r86",
      "r439"
     ]
    },
    "ifrs-full_DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of information for cash-generating units [line items]",
        "label": "Disclosure of information for cash-generating units [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesTable",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of information for cash-generating units [table]",
        "label": "Disclosure of information for cash-generating units [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to cash-generating units."
       }
      }
     },
     "auth_ref": [
      "r86",
      "r439"
     ]
    },
    "ifrs-full_DisclosureOfIntangibleAssetsAndGoodwillExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfIntangibleAssetsAndGoodwillExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Goodwillandintangibleassets"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Goodwill and intangible assets",
        "label": "Disclosure of intangible assets and goodwill [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of intangible assets and goodwill. [Refer: Intangible assets and goodwill]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfIntangibleAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfIntangibleAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of reconciliation of changes in intangible assets and goodwill",
        "label": "Disclosure of intangible assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure for intangible assets."
       }
      }
     },
     "auth_ref": [
      "r105"
     ]
    },
    "ifrs-full_DisclosureOfInterestIncomeExpenseExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInterestIncomeExpenseExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Netinterestincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net interest income",
        "label": "Disclosure of interest income (expense) [text block]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfInterestsInOtherEntitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInterestsInOtherEntitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertaking"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Related Undertakings",
        "label": "Disclosure of interests in other entities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure for interests in other entities."
       }
      }
     },
     "auth_ref": [
      "r134"
     ]
    },
    "bbplc_DisclosureOfInterestsInOtherRelatedUndertakingsTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfInterestsInOtherRelatedUndertakingsTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of other related undertakings",
        "label": "Disclosure Of Interests In Other Related Undertakings [Table Text Block]",
        "documentation": "Disclosure Of Interests In Other Related Undertakings"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfInterestsInSubsidiariesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInterestsInSubsidiariesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of wholly owned subsidiaries",
        "label": "Disclosure of interests in subsidiaries [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of interests in subsidiaries. [Refer: Total for all subsidiaries [member]]"
       }
      }
     },
     "auth_ref": [
      "r139"
     ]
    },
    "ifrs-full_DisclosureOfInterestsInUnconsolidatedStructuredEntitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInterestsInUnconsolidatedStructuredEntitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of entities excluded from consolidation",
        "label": "Disclosure of interests in unconsolidated structured entities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of interests in structured entities that are not controlled by the entity (unconsolidated structured entities). [Refer: Total for all unconsolidated structured entities [member]]"
       }
      }
     },
     "auth_ref": [
      "r140"
     ]
    },
    "ifrs-full_DisclosureOfInternalCreditExposuresLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInternalCreditExposuresLineItems",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of internal credit grades [line items]",
        "label": "Disclosure of internal credit grades [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfInternalCreditExposuresTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfInternalCreditExposuresTable",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of internal credit grades [table]",
        "label": "Disclosure of internal credit grades [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to internal credit grades."
       }
      }
     },
     "auth_ref": [
      "r545",
      "r715"
     ]
    },
    "bbplc_DisclosureOfInvestmentsInAssociatesAndJointVenturesTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfInvestmentsInAssociatesAndJointVenturesTextBlock",
     "presentation": [
      "http://www.home.barclays/role/Investmentsinassociatesandjointventures"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Investments in associates and joint ventures",
        "label": "Disclosure Of Investments In Associates And Joint Ventures [Text Block]",
        "documentation": "The entire disclosure investments in associates and joint ventures."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfIssuedCapitalExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfIssuedCapitalExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Ordinarysharespreferencesharesandotherequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Ordinary shares, preference shares and other equity",
        "label": "Disclosure of issued capital [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of issued capital. [Refer: Issued capital]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfLeasesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfLeasesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Leases"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Leases",
        "label": "Disclosure of leases [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure for leases."
       }
      }
     },
     "auth_ref": [
      "r198",
      "r199"
     ]
    },
    "ifrs-full_DisclosureOfMaterialAccountingPolicyInformationExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfMaterialAccountingPolicyInformationExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Materialaccountingpolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Material accounting policies",
        "label": "Disclosure of material accounting policy information [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure of material accounting policy information applied by the entity."
       }
      }
     },
     "auth_ref": [
      "r388",
      "r540",
      "r558"
     ]
    },
    "ifrs-full_DisclosureOfMaturityAnalysisForFinancialAssetsHeldForManagingLiquidityRiskExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfMaturityAnalysisForFinancialAssetsHeldForManagingLiquidityRiskExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of contractual maturity of financial assets and liabilities",
        "label": "Disclosure of maturity analysis for financial assets held for managing liquidity risk [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of a maturity analysis for financial assets held for managing liquidity risk. [Refer: Financial assets; Liquidity risk [member]]"
       }
      }
     },
     "auth_ref": [
      "r322"
     ]
    },
    "ifrs-full_DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofmaturityanalysisofleaseliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of maturity analysis for non-derivative financial liabilities [line items]",
        "label": "Disclosure of maturity analysis for non-derivative financial liabilities [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesTable",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofmaturityanalysisofleaseliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of maturity analysis for non-derivative financial liabilities [table]",
        "label": "Disclosure of maturity analysis for non-derivative financial liabilities [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the maturity analysis for non-derivative financial liabilities."
       }
      }
     },
     "auth_ref": [
      "r298",
      "r518"
     ]
    },
    "ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of nature and extent of risks arising from financial instruments [abstract]",
        "label": "Disclosure of nature and extent of risks arising from financial instruments [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of nature and extent of risks arising from financial instruments [line items]",
        "label": "Disclosure of nature and extent of risks arising from financial instruments [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of nature and extent of risks arising from financial instruments [table]",
        "label": "Disclosure of nature and extent of risks arising from financial instruments [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the nature and extent of risks arising from financial instruments."
       }
      }
     },
     "auth_ref": [
      "r277",
      "r279"
     ]
    },
    "ifrs-full_DisclosureOfNetDefinedBenefitLiabilityAssetExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfNetDefinedBenefitLiabilityAssetExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Disclosure of balance sheet reconciliation",
        "label": "Disclosure of net defined benefit liability (asset) [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of a net defined benefit liability (asset). [Refer: Net defined benefit liability (asset)]"
       }
      }
     },
     "auth_ref": [
      "r22",
      "r406"
     ]
    },
    "ifrs-full_DisclosureOfNetDefinedBenefitLiabilityAssetLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfNetDefinedBenefitLiabilityAssetLineItems",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of net defined benefit liability (asset) [line items]",
        "label": "Disclosure of net defined benefit liability (asset) [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfNetDefinedBenefitLiabilityAssetTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfNetDefinedBenefitLiabilityAssetTable",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of net defined benefit liability (asset) [table]",
        "label": "Disclosure of net defined benefit liability (asset) [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the net defined benefit liability (asset)."
       }
      }
     },
     "auth_ref": [
      "r22",
      "r406"
     ]
    },
    "bbplc_DisclosureOfNetInterestIncomeTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfNetInterestIncomeTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/NetinterestincomeTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Summary of net interest income",
        "label": "Disclosure Of Net Interest Income [Table Text Block]",
        "documentation": "The disclosure of net interest income. [Refer: Interest income (expense)]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DisclosureOfNetInvestmentIncomeTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfNetInvestmentIncomeTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/NetinvestmentexpenseincomeTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of net investment (expense) / income",
        "label": "Disclosure Of Net Investment Income [Table Text Block]",
        "documentation": "The disclosure of net fee and commission income. [Refer: Fee and commission income (expense)]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DisclosureOfNetTradingIncomeTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfNetTradingIncomeTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/NettradingincomeTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of net trading income",
        "label": "Disclosure Of Net Trading Income [Table Text Block]",
        "documentation": "The disclosure of net trading income. [Refer: Trading income (expense)]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfNoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Assetsandliabilitiesincludedindisposalgroupclassifiedasheldforsale"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets and liabilities included in disposal group classified as held for sale",
        "label": "Disclosure of non-current assets or disposal groups classified as held for sale [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of non-current assets or disposal groups classified as held for sale. [Refer: Non-current assets or disposal groups classified as held for sale]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfNumberAndWeightedAverageExercisePricesOfShareOptionsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfNumberAndWeightedAverageExercisePricesOfShareOptionsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of movements in options and awards",
        "label": "Disclosure of number and weighted average exercise prices of share options [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the number and weighted average exercise prices of share options. [Refer: Weighted average [member]]"
       }
      }
     },
     "auth_ref": [
      "r220",
      "r468"
     ]
    },
    "ifrs-full_DisclosureOfObjectivesPoliciesAndProcessesForManagingCapitalAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfObjectivesPoliciesAndProcessesForManagingCapitalAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of objectives, policies and processes for managing capital [abstract]",
        "label": "Disclosure of objectives, policies and processes for managing capital [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfObjectivesPoliciesAndProcessesForManagingCapitalExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfObjectivesPoliciesAndProcessesForManagingCapitalExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RiskManagement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Risk Management",
        "label": "Disclosure of objectives, policies and processes for managing capital [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of information that enables users of financial statements to evaluate the entity's objectives, policies and processes for managing capital."
       }
      }
     },
     "auth_ref": [
      "r560"
     ]
    },
    "ifrs-full_DisclosureOfObjectivesPoliciesAndProcessesForManagingCapitalLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfObjectivesPoliciesAndProcessesForManagingCapitalLineItems",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcapitalresourcesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of objectives, policies and processes for managing capital [line items]",
        "label": "Disclosure of objectives, policies and processes for managing capital [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfObjectivesPoliciesAndProcessesForManagingCapitalTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfObjectivesPoliciesAndProcessesForManagingCapitalTable",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcapitalresourcesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of objectives, policies and processes for managing capital [table]",
        "label": "Disclosure of objectives, policies and processes for managing capital [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the objectives, policies and processes for managing capital."
       }
      }
     },
     "auth_ref": [
      "r561"
     ]
    },
    "ifrs-full_DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOffsettingOfFinancialAssetsAndFinancialLiabilitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Offsettingfinancialassetsandfinancialliabilities"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Offsetting financial assets and financial liabilities",
        "label": "Disclosure of offsetting of financial assets and financial liabilities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the offsetting of financial assets and financial liabilities. [Refer: Financial assets; Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r329"
     ]
    },
    "ifrs-full_DisclosureOfOffsettingOfFinancialAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOffsettingOfFinancialAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of offsetting of financial assets",
        "label": "Disclosure of offsetting of financial assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the offsetting of financial assets. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r243"
     ]
    },
    "ifrs-full_DisclosureOfOffsettingOfFinancialAssetsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOffsettingOfFinancialAssetsLineItems",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of offsetting of financial assets [line items]",
        "label": "Disclosure of offsetting of financial assets [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfOffsettingOfFinancialAssetsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOffsettingOfFinancialAssetsTable",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of offsetting of financial assets [table]",
        "label": "Disclosure of offsetting of financial assets [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the offsetting of financial assets."
       }
      }
     },
     "auth_ref": [
      "r243"
     ]
    },
    "ifrs-full_DisclosureOfOffsettingOfFinancialLiabilitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOffsettingOfFinancialLiabilitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of offsetting of financial liabilities",
        "label": "Disclosure of offsetting of financial liabilities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the offsetting of financial liabilities. [Refer: Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r243"
     ]
    },
    "ifrs-full_DisclosureOfOffsettingOfFinancialLiabilitiesLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOffsettingOfFinancialLiabilitiesLineItems",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcarryingamountoftheassetspledgedassecurityagainstliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of offsetting of financial liabilities [line items]",
        "label": "Disclosure of offsetting of financial liabilities [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfOffsettingOfFinancialLiabilitiesTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOffsettingOfFinancialLiabilitiesTable",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcarryingamountoftheassetspledgedassecurityagainstliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of offsetting of financial liabilities [table]",
        "label": "Disclosure of offsetting of financial liabilities [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the offsetting of financial liabilities."
       }
      }
     },
     "auth_ref": [
      "r243"
     ]
    },
    "ifrs-full_DisclosureOfOperatingSegmentsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOperatingSegmentsAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of operating segments [abstract]",
        "label": "Disclosure of operating segments [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfOperatingSegmentsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOperatingSegmentsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/SegmentalreportingTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of analysis of results by business",
        "label": "Disclosure of operating segments [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of operating segments. [Refer: Operating segments [member]]"
       }
      }
     },
     "auth_ref": [
      "r335"
     ]
    },
    "ifrs-full_DisclosureOfOperatingSegmentsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOperatingSegmentsLineItems",
     "presentation": [
      "http://www.home.barclays/role/AcquisitionandDisposalsofsubsidiariesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails",
      "http://www.home.barclays/role/SegmentalreportingNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of operating segments [line items]",
        "label": "Disclosure of operating segments [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfOperatingSegmentsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOperatingSegmentsTable",
     "presentation": [
      "http://www.home.barclays/role/AcquisitionandDisposalsofsubsidiariesDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofgoodwillallocatedtobusinessoperationsaccordingtobusinesssegmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails",
      "http://www.home.barclays/role/SegmentalreportingNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of operating segments [table]",
        "label": "Disclosure of operating segments [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to operating segments."
       }
      }
     },
     "auth_ref": [
      "r335"
     ]
    },
    "ifrs-full_DisclosureOfOtherLiabilitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOtherLiabilitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/OtherliabilitiesTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of other liabilities",
        "label": "Disclosure of other liabilities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of other liabilities. [Refer: Other liabilities]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfOtherProvisionsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOtherProvisionsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of movements in provisions",
        "label": "Disclosure of other provisions [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of other provisions. [Refer: Other provisions]"
       }
      }
     },
     "auth_ref": [
      "r95",
      "r445"
     ]
    },
    "ifrs-full_DisclosureOfOtherProvisionsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOtherProvisionsLineItems",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails",
      "http://www.home.barclays/role/ProvisionsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of other provisions [line items]",
        "label": "Disclosure of other provisions [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfOtherProvisionsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfOtherProvisionsTable",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails",
      "http://www.home.barclays/role/ProvisionsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of other provisions [table]",
        "label": "Disclosure of other provisions [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to other provisions."
       }
      }
     },
     "auth_ref": [
      "r95",
      "r445"
     ]
    },
    "ifrs-full_DisclosureOfProductsAndServicesLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfProductsAndServicesLineItems",
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails",
      "http://www.home.barclays/role/AuditorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of products and services [line items]",
        "label": "Disclosure of products and services [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfProductsAndServicesTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfProductsAndServicesTable",
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails",
      "http://www.home.barclays/role/AuditorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of products and services [table]",
        "label": "Disclosure of products and services [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the entity's products and services."
       }
      }
     },
     "auth_ref": [
      "r342"
     ]
    },
    "ifrs-full_DisclosureOfPropertyPlantAndEquipmentAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfPropertyPlantAndEquipmentAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of detailed information about property, plant and equipment [abstract]",
        "label": "Disclosure of detailed information about property, plant and equipment [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfPropertyPlantAndEquipmentExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfPropertyPlantAndEquipmentExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Propertyplantandequipment"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Property, plant and equipment",
        "label": "Disclosure of property, plant and equipment [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure for property, plant and equipment."
       }
      }
     },
     "auth_ref": [
      "r18"
     ]
    },
    "ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfPropertyPlantAndEquipmentLineItems",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentNarrativeDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of detailed information about property, plant and equipment [line items]",
        "label": "Disclosure of detailed information about property, plant and equipment [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfPropertyPlantAndEquipmentTable",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentNarrativeDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of detailed information about property, plant and equipment [table]",
        "label": "Disclosure of detailed information about property, plant and equipment [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to details of property, plant and equipment."
       }
      }
     },
     "auth_ref": [
      "r16",
      "r402"
     ]
    },
    "ifrs-full_DisclosureOfProvisionMatrixExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfProvisionMatrixExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of loans and advances at amortised cost by product",
        "label": "Disclosure of provision matrix [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the provision matrix."
       }
      }
     },
     "auth_ref": [
      "r669"
     ]
    },
    "ifrs-full_DisclosureOfProvisionsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfProvisionsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Provisions"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Provisions",
        "label": "Disclosure of provisions [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of provisions. [Refer: Provisions]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "bbplc_DisclosureOfReconciliationOfActualTaxRateToCorporateTaxRateTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfReconciliationOfActualTaxRateToCorporateTaxRateTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/TaxTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of reconciliation between the actual tax charge and the corporate tax rate",
        "label": "Disclosure Of Reconciliation Of Actual Tax Rate To Corporate Tax Rate [Table Text Block]",
        "documentation": "The tabular disclosure of the reconciliation of the actual tax charge and the tax charge that would result from applying the standard UK corporation tax rate to the entity's profit before tax."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillLineItems",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofgoodwillallocatedtobusinessoperationsaccordingtobusinesssegmentsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of reconciliation of changes in intangible assets and goodwill [line items]",
        "label": "Disclosure of reconciliation of changes in intangible assets and goodwill [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfReconciliationOfChangesInIntangibleAssetsAndGoodwillTable",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of reconciliation of changes in intangible assets and goodwill [table]",
        "label": "Disclosure of reconciliation of changes in intangible assets and goodwill [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the reconciliation of changes in intangible assets and goodwill."
       }
      }
     },
     "auth_ref": [
      "r858"
     ]
    },
    "ifrs-full_DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsLineItems",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]",
        "label": "Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfReconciliationOfChangesInLossAllowanceAndExplanationOfChangesInGrossCarryingAmountForFinancialInstrumentsTable",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [table]",
        "label": "Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the reconciliation of changes in the loss allowance and explanation of changes in the gross carrying amount for financial instruments."
       }
      }
     },
     "auth_ref": [
      "r285",
      "r286",
      "r511",
      "r513"
     ]
    },
    "ifrs-full_DisclosureOfReconciliationOfChangesInPropertyPlantAndEquipmentIncludingRightofuseAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfReconciliationOfChangesInPropertyPlantAndEquipmentIncludingRightofuseAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of reconciliation of changes in property, plant and equipment, including right-of-use assets",
        "label": "Disclosure of reconciliation of changes in property, plant and equipment, including right-of-use assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the reconciliation of changes in property, plant and equipment, including right-of-use assets."
       }
      }
     },
     "auth_ref": [
      "r840"
     ]
    },
    "ifrs-full_DisclosureOfRelatedPartyExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfRelatedPartyExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremuneration"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Related party transactions and Directors' remuneration",
        "label": "Disclosure of related party [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure for related parties."
       }
      }
     },
     "auth_ref": [
      "r60"
     ]
    },
    "ifrs-full_DisclosureOfReservesAndOtherEquityInterestExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfReservesAndOtherEquityInterestExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Reserves"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reserves",
        "label": "Disclosure of reserves within equity [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of reserves within equity. [Refer: Other reserves [member]]"
       }
      }
     },
     "auth_ref": [
      "r381",
      "r538",
      "r585"
     ]
    },
    "ifrs-full_DisclosureOfReservesWithinEquityAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfReservesWithinEquityAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of reserves within equity [abstract]",
        "label": "Disclosure of reserves within equity [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfReservesWithinEquityLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfReservesWithinEquityLineItems",
     "presentation": [
      "http://www.home.barclays/role/ReservesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of reserves within equity [line items]",
        "label": "Disclosure of reserves within equity [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfReservesWithinEquityTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfReservesWithinEquityTable",
     "presentation": [
      "http://www.home.barclays/role/ReservesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of reserves within equity [table]",
        "label": "Disclosure of reserves within equity [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to reserves within equity."
       }
      }
     },
     "auth_ref": [
      "r381",
      "r538",
      "r585"
     ]
    },
    "bbplc_DisclosureOfReservesWithinEquityTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfReservesWithinEquityTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/ReservesTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Disclosure of reserves within equity",
        "label": "Disclosure Of Reserves Within Equity [Table Text Block]",
        "documentation": "The tabular disclosure of other reserves within equity."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfRiskManagementStrategyRelatedToHedgeAccountingExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfRiskManagementStrategyRelatedToHedgeAccountingExplanatory",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of derivatives held for trading and risk management",
        "label": "Disclosure of risk management strategy related to hedge accounting [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of risk management strategy related to hedge accounting."
       }
      }
     },
     "auth_ref": [
      "r252",
      "r490",
      "r544"
     ]
    },
    "ifrs-full_DisclosureOfRiskManagementStrategyRelatedToHedgeAccountingLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfRiskManagementStrategyRelatedToHedgeAccountingLineItems",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of risk management strategy related to hedge accounting [line items]",
        "label": "Disclosure of risk management strategy related to hedge accounting [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfRiskManagementStrategyRelatedToHedgeAccountingTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfRiskManagementStrategyRelatedToHedgeAccountingTable",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of risk management strategy related to hedge accounting [table]",
        "label": "Disclosure of risk management strategy related to hedge accounting [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the risk management strategy in relation to hedge accounting."
       }
      }
     },
     "auth_ref": [
      "r252",
      "r490",
      "r544"
     ]
    },
    "ifrs-full_DisclosureOfSensitivityAnalysisForActuarialAssumptionsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSensitivityAnalysisForActuarialAssumptionsAbstract",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Sensitivity of key judgements",
        "label": "Disclosure of sensitivity analysis for actuarial assumptions [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfSensitivityAnalysisForActuarialAssumptionsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSensitivityAnalysisForActuarialAssumptionsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of actuarial valuation of schemes",
        "label": "Disclosure of sensitivity analysis for actuarial assumptions [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of a sensitivity analysis for significant actuarial assumptions used to determine the present value of a defined benefit obligation. [Refer: Actuarial assumptions [domain]; Defined benefit obligation, at present value]"
       }
      }
     },
     "auth_ref": [
      "r35"
     ]
    },
    "ifrs-full_DisclosureOfSensitivityAnalysisForActuarialAssumptionsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSensitivityAnalysisForActuarialAssumptionsLineItems",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of sensitivity analysis for actuarial assumptions [line items]",
        "label": "Disclosure of sensitivity analysis for actuarial assumptions [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfSensitivityAnalysisForActuarialAssumptionsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSensitivityAnalysisForActuarialAssumptionsTable",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of sensitivity analysis for actuarial assumptions [table]",
        "label": "Disclosure of sensitivity analysis for actuarial assumptions [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the sensitivity analysis for actuarial assumptions."
       }
      }
     },
     "auth_ref": [
      "r35"
     ]
    },
    "ifrs-full_DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of sensitivity analysis of valuations using unobservable inputs, assets",
        "label": "Disclosure of sensitivity analysis of fair value measurement to changes in unobservable inputs, assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the sensitivity analysis of fair value measurement of assets to changes in unobservable inputs."
       }
      }
     },
     "auth_ref": [
      "r172"
     ]
    },
    "ifrs-full_DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsLiabilitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsLiabilitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of sensitivity analysis of valuations using unobservable inputs, liabilities",
        "label": "Disclosure of sensitivity analysis of fair value measurement to changes in unobservable inputs, liabilities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the sensitivity analysis of the fair value measurement of liabilities to changes in unobservable inputs."
       }
      }
     },
     "auth_ref": [
      "r172"
     ]
    },
    "ifrs-full_DisclosureOfSensitivityAnalysisToChangesInRiskExposuresThatAriseFromContractsWithinScopeOfIFRS17Explanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSensitivityAnalysisToChangesInRiskExposuresThatAriseFromContractsWithinScopeOfIFRS17Explanatory",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of net interest income sensitivity (AEaR) by currency and analysis of equity sensitivity",
        "label": "Disclosure of sensitivity analysis to changes in risk variables that arise from contracts within scope of IFRS 17 [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the sensitivity analysis to changes in risk variables that arise from contracts within the scope of IFRS 17."
       }
      }
     },
     "auth_ref": [
      "r208"
     ]
    },
    "ifrs-full_DisclosureOfSensitivityAnalysisToChangesInRiskExposuresThatAriseFromContractsWithinScopeOfIFRS17LineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSensitivityAnalysisToChangesInRiskExposuresThatAriseFromContractsWithinScopeOfIFRS17LineItems",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of sensitivity analysis to changes in risk exposures that arise from contracts within scope of IFRS 17 [line items]",
        "label": "Disclosure of sensitivity analysis to changes in risk variables that arise from contracts within scope of IFRS 17 [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfSensitivityAnalysisToChangesInRiskExposuresThatAriseFromContractsWithinScopeOfIFRS17Table": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSensitivityAnalysisToChangesInRiskExposuresThatAriseFromContractsWithinScopeOfIFRS17Table",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of sensitivity analysis to changes in risk exposures that arise from contracts within scope of IFRS 17 [table]",
        "label": "Disclosure of sensitivity analysis to changes in risk variables that arise from contracts within scope of IFRS 17 [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to the sensitivity analysis to changes in risk variables that arise from contracts within the scope of IFRS 17."
       }
      }
     },
     "auth_ref": [
      "r208"
     ]
    },
    "ifrs-full_DisclosureOfShareCapitalReservesAndOtherEquityInterestExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfShareCapitalReservesAndOtherEquityInterestExplanatory",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of AT1 equity instruments",
        "label": "Disclosure of share capital, reserves and other equity interest [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure for share capital, reserves and other equity interest."
       }
      }
     },
     "auth_ref": [
      "r382",
      "r539",
      "r586"
     ]
    },
    "ifrs-full_DisclosureOfSharebasedPaymentArrangementsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSharebasedPaymentArrangementsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Sharebasedpayments"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Share-based payments",
        "label": "Disclosure of share-based payment arrangements [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The entire disclosure for share-based payment arrangements."
       }
      }
     },
     "auth_ref": [
      "r212"
     ]
    },
    "bbplc_DisclosureOfShortTermEmployeeBenefitsExplanatoryTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfShortTermEmployeeBenefitsExplanatoryTextBlock",
     "presentation": [
      "http://www.home.barclays/role/Staffcosts"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Staff costs",
        "label": "Disclosure Of Short-Term Employee Benefits Explanatory [Text Block]",
        "documentation": "The entire disclosure for short-term employee benefits."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfSignificantInvestmentsInAssociatesLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSignificantInvestmentsInAssociatesLineItems",
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresDisclosureofinvestmentsinassociatesandjointventuresDetails",
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of associates [line items]",
        "label": "Disclosure of associates [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfSignificantInvestmentsInAssociatesTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSignificantInvestmentsInAssociatesTable",
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresDisclosureofinvestmentsinassociatesandjointventuresDetails",
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of associates [table]",
        "label": "Disclosure of associates [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to associates."
       }
      }
     },
     "auth_ref": [
      "r65",
      "r67",
      "r159",
      "r524"
     ]
    },
    "ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSignificantInvestmentsInSubsidiariesAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of subsidiaries [abstract]",
        "label": "Disclosure of subsidiaries [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSignificantInvestmentsInSubsidiariesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Principalsubsidiaries"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Principal subsidiaries",
        "label": "Disclosure of subsidiaries [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of subsidiaries. [Refer: Total for all subsidiaries [member]]"
       }
      }
     },
     "auth_ref": [
      "r65",
      "r67",
      "r157",
      "r522"
     ]
    },
    "ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSignificantInvestmentsInSubsidiariesLineItems",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of subsidiaries [line items]",
        "label": "Disclosure of subsidiaries [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfSignificantInvestmentsInSubsidiariesTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSignificantInvestmentsInSubsidiariesTable",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of subsidiaries [table]",
        "label": "Disclosure of subsidiaries [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to subsidiaries."
       }
      }
     },
     "auth_ref": [
      "r65",
      "r67",
      "r157",
      "r522"
     ]
    },
    "ifrs-full_DisclosureOfSignificantUnobservableInputsUsedInFairValueMeasurementOfAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSignificantUnobservableInputsUsedInFairValueMeasurementOfAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of significant unobservable inputs, assets",
        "label": "Disclosure of significant unobservable inputs used in fair value measurement of assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of significant inputs for which market data are not available and that are developed using the best information available about the assumptions that market participants would use when measuring the fair value of assets."
       }
      }
     },
     "auth_ref": [
      "r165"
     ]
    },
    "ifrs-full_DisclosureOfSignificantUnobservableInputsUsedInFairValueMeasurementOfLiabilitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSignificantUnobservableInputsUsedInFairValueMeasurementOfLiabilitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of significant unobservable inputs, liabilities",
        "label": "Disclosure of significant unobservable inputs used in fair value measurement of liabilities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of significant inputs for which market data are not available and that are developed using the best information available about the assumptions that market participants would use when measuring the fair value of liabilities."
       }
      }
     },
     "auth_ref": [
      "r165"
     ]
    },
    "bbplc_DisclosureOfStockOptionsAndAwardPlanOfShareBasedPaymentArrangementTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfStockOptionsAndAwardPlanOfShareBasedPaymentArrangementTextBlock",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of share option and award plans",
        "label": "Disclosure Of Stock Options And Award Plan Of Share-Based Payment Arrangement [Text Block]",
        "documentation": "The disclosure of stock options and award plan of share-based payment arrangements."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfSubordinatedLiabilitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfSubordinatedLiabilitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Subordinatedliabilities"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Subordinated liabilities",
        "label": "Disclosure of subordinated liabilities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of subordinated liabilities. [Refer: Subordinated liabilities]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "bbplc_DisclosureOfSummaryOfDerivativeAssetsAndLiabilitiesTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfSummaryOfDerivativeAssetsAndLiabilitiesTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of total derivatives",
        "label": "Disclosure Of Summary Of Derivative Assets And Liabilities [Table Text Block]",
        "documentation": "The tabular disclosure summarizing derivative financial assets and liabilities of the entity."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/TaxTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of movements on deferred tax assets and liabilities during the year before offsetting",
        "label": "Disclosure of temporary difference, unused tax losses and unused tax credits [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of types of temporary differences, unused tax losses and unused tax credits. [Refer: Unused tax credits [member]; Unused tax losses [member]; Temporary differences [member]]"
       }
      }
     },
     "auth_ref": [
      "r10",
      "r397"
     ]
    },
    "ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails",
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of temporary difference, unused tax losses and unused tax credits [line items]",
        "label": "Disclosure of temporary difference, unused tax losses and unused tax credits [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails",
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of temporary difference, unused tax losses and unused tax credits [table]",
        "label": "Disclosure of temporary difference, unused tax losses and unused tax credits [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to temporary differences, unused tax losses and unused tax credits."
       }
      }
     },
     "auth_ref": [
      "r10",
      "r397"
     ]
    },
    "ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of terms and conditions of share-based payment arrangement [abstract]",
        "label": "Disclosure of terms and conditions of share-based payment arrangement [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementExplanatory",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of share-based payment schemes",
        "label": "Disclosure of terms and conditions of share-based payment arrangement [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of the general terms and conditions of share-based payment arrangements. [Refer: Types of share-based payment arrangements [domain]]"
       }
      }
     },
     "auth_ref": [
      "r223",
      "r469"
     ]
    },
    "ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofsharebasedpaymentschemesDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails",
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of terms and conditions of share-based payment arrangement [line items]",
        "label": "Disclosure of terms and conditions of share-based payment arrangement [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofsharebasedpaymentschemesDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails",
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of terms and conditions of share-based payment arrangement [table]",
        "label": "Disclosure of terms and conditions of share-based payment arrangement [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to terms and conditions of share-based payment arrangements."
       }
      }
     },
     "auth_ref": [
      "r223",
      "r469"
     ]
    },
    "ifrs-full_DisclosureOfTradingIncomeExpenseExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfTradingIncomeExpenseExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Nettradingincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net trading income",
        "label": "Disclosure of trading income (expense) [text block]"
       }
      }
     },
     "auth_ref": [
      "r876"
     ]
    },
    "ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfTransactionsBetweenRelatedPartiesAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of transactions between related parties [abstract]",
        "label": "Disclosure of transactions between related parties [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfTransactionsBetweenRelatedPartiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of loans and deposits outstanding",
        "label": "Disclosure of transactions between related parties [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of transactions between the entity and its related parties. [Refer: Total for all related parties [member]]"
       }
      }
     },
     "auth_ref": [
      "r51",
      "r422"
     ]
    },
    "ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfTransactionsBetweenRelatedPartiesLineItems",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofamountsincludedintheGroupsfinancialstatementsbycategoryDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofloansanddepositsoutstandingDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of transactions between related parties [line items]",
        "label": "Disclosure of transactions between related parties [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfTransactionsBetweenRelatedPartiesTable",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofamountsincludedintheGroupsfinancialstatementsbycategoryDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofloansanddepositsoutstandingDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of transactions between related parties [table]",
        "label": "Disclosure of transactions between related parties [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to transactions between related parties."
       }
      }
     },
     "auth_ref": [
      "r58",
      "r428"
     ]
    },
    "ifrs-full_DisclosureOfTransfersOfFinancialAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfTransfersOfFinancialAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/Securitisations"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Securitisations",
        "label": "Disclosure of transfers of financial assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of transfers of financial assets. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r330"
     ]
    },
    "ifrs-full_DisclosureOfUnconsolidatedStructuredEntitiesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfUnconsolidatedStructuredEntitiesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Summary of interests in unconsolidated structured entities and nature of interests",
        "label": "Disclosure of unconsolidated structured entities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of unconsolidated structured entities. [Refer: Total for all unconsolidated structured entities [member]]"
       }
      }
     },
     "auth_ref": [
      "r160",
      "r525"
     ]
    },
    "ifrs-full_DisclosureOfUnconsolidatedStructuredEntitiesLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfUnconsolidatedStructuredEntitiesLineItems",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredNarrativeDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails",
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of unconsolidated structured entities [line items]",
        "label": "Disclosure of unconsolidated structured entities [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisclosureOfUnconsolidatedStructuredEntitiesTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisclosureOfUnconsolidatedStructuredEntitiesTable",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of unconsolidated structured entities [table]",
        "label": "Disclosure of unconsolidated structured entities [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to unconsolidated structured entities."
       }
      }
     },
     "auth_ref": [
      "r160",
      "r525"
     ]
    },
    "bbplc_DisclosureOfUnrealisedGainsLossesRecognisedOnAssetsAndLiabilitiesTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureOfUnrealisedGainsLossesRecognisedOnAssetsAndLiabilitiesTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of unrealised gains and losses on Level 3 financial assets and liabilities",
        "label": "Disclosure Of Unrealised Gains (Losses) Recognised On Assets And Liabilities [Table Text Block]",
        "documentation": "The tabular disclosure of unrealised gains and losses recognised during the period on assets and liabilities held at period end."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DisclosureRequiredByCompaniesAct2006TableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisclosureRequiredByCompaniesAct2006TableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure required by the Companies Act 2006",
        "label": "Disclosure Required By Companies Act 2006 [Table Text Block]",
        "documentation": "The disclosure presents information regarding directors in accordance with companies act 2006."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DiscountRateMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DiscountRateMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Discount margin",
        "verboseLabel": "Discount rate",
        "label": "Discount rate, measurement input [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a discount rate used as a measurement input used in valuation techniques based on a present value calculation."
       }
      }
     },
     "auth_ref": [
      "r869"
     ]
    },
    "ifrs-full_DiscountedCashFlowMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DiscountedCashFlowMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Discounted cash flows",
        "label": "Discounted cash flow [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a specific valuation technique consistent with the income approach that involves analysing future cash flow amounts through the application of present value techniques and inputs (for example, weighted average cost of capital, long-term revenue growth rate, long-term pre-tax operating margin, discount for lack of marketability, control premium). [Refer: Income approach [member]; Weighted average [member]]"
       }
      }
     },
     "auth_ref": [
      "r641",
      "r651"
     ]
    },
    "ifrs-full_DisposalGroupsClassifiedAsHeldForSaleMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisposalGroupsClassifiedAsHeldForSaleMember",
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disposal groups classified as held for sale",
        "label": "Disposal groups classified as held for sale [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for groups of assets, which are to be disposed of together as a group in a single transaction, and the liabilities directly associated with those assets that will be transferred in the transaction."
       }
      }
     },
     "auth_ref": [
      "r235",
      "r871"
     ]
    },
    "ifrs-full_DisposalsIntangibleAssetsAndGoodwill": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisposalsIntangibleAssetsAndGoodwill",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Disposals",
        "label": "Disposals, intangible assets and goodwill"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease in intangible assets and goodwill resulting from disposals. [Refer: Intangible assets and goodwill]"
       }
      }
     },
     "auth_ref": [
      "r855"
     ]
    },
    "bbplc_DisposalsOfBusinessesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DisposalsOfBusinessesAbstract",
     "lang": {
      "en-us": {
       "role": {
        "label": "Disposals Of Businesses [Abstract]",
        "documentation": "Disposals Of Businesses"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DisposalsPropertyPlantAndEquipmentIncludingRightofuseAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DisposalsPropertyPlantAndEquipmentIncludingRightofuseAssets",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Disposals",
        "label": "Disposals, property, plant and equipment including right-of-use assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease in property, plant and equipment including right-of-use assets resulting from disposals. [Refer: Property, plant and equipment including right-of-use assets]"
       }
      }
     },
     "auth_ref": [
      "r840"
     ]
    },
    "bbplc_DividendsOnOrdinarySharesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DividendsOnOrdinarySharesAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "11. Dividends on ordinary shares",
        "label": "Dividends On Ordinary Shares [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DividendsPaidAndOtherCouponPaymentsOnEquityInstrumentsClassifiedAsFinancingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DividendsPaidAndOtherCouponPaymentsOnEquityInstrumentsClassifiedAsFinancingActivities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities",
       "weight": -1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Dividends paid and other coupon payments on equity instruments",
        "label": "Dividends Paid And Other Coupon Payments On Equity Instruments, Classified As Financing Activities",
        "documentation": "The cash outflow for dividends paid by the entity and issue costs on equity instruments, classified as financing activities."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_DividendsPaidOrdinaryShares": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DividendsPaidOrdinaryShares",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Dividends on ordinary shares",
        "negatedLabel": "Dividends on ordinary shares",
        "terseLabel": "Dividends paid, ordinary shares",
        "label": "Dividends paid, ordinary shares"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of dividends paid by the entity on ordinary shares. [Refer: Ordinary shares [member]]"
       }
      }
     },
     "auth_ref": [
      "r69",
      "r431"
     ]
    },
    "ifrs-full_DividendsPaidOrdinarySharesPerShare": {
     "xbrltype": "perShareItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DividendsPaidOrdinarySharesPerShare",
     "presentation": [
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Dividends paid on ordinary shares (in GBP per share)",
        "label": "Dividends paid, ordinary shares per share"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of dividends paid per ordinary share."
       }
      }
     },
     "auth_ref": [
      "r69",
      "r431"
     ]
    },
    "ifrs-full_DividendsPaidOtherShares": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DividendsPaidOtherShares",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Dividends on preference shares and other shareholders equity",
        "negatedLabel": "Dividends on preference shares and other shareholders equity",
        "terseLabel": "Dividends on preference shares and other shareholders equity",
        "label": "Dividends paid, other shares"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of dividends paid by the entity on shares other than ordinary shares. [Refer: Ordinary shares [member]]"
       }
      }
     },
     "auth_ref": [
      "r69",
      "r431"
     ]
    },
    "ifrs-full_DividendsPaidOtherSharesPerShare": {
     "xbrltype": "perShareItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DividendsPaidOtherSharesPerShare",
     "presentation": [
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Dividends paid on preference shares (in GBP per share)",
        "label": "Dividends paid, other shares per share"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of dividends paid per other share."
       }
      }
     },
     "auth_ref": [
      "r69",
      "r431"
     ]
    },
    "ifrs-full_DividendsPaidToEquityHoldersOfParentClassifiedAsFinancingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DividendsPaidToEquityHoldersOfParentClassifiedAsFinancingActivities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincomeParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Dividends paid to equity holders of parent, classified as financing activities",
        "label": "Dividends paid to equity holders of parent, classified as financing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash outflow for dividends paid to equity holders of the parent, classified as financing activities."
       }
      }
     },
     "auth_ref": [
      "r864"
     ]
    },
    "ifrs-full_DividendsProposedOrDeclaredBeforeFinancialStatementsAuthorisedForIssueButNotRecognisedAsDistributionToOwners": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DividendsProposedOrDeclaredBeforeFinancialStatementsAuthorisedForIssueButNotRecognisedAsDistributionToOwners",
     "presentation": [
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Dividends approved but not recognised",
        "label": "Dividends proposed or declared before financial statements authorised for issue but not recognised as distribution to owners"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of dividends proposed or declared after the reporting period but before financial statements are authorised for issue. Such dividends are not recognised as a liability at the end of the reporting period because no obligation exists at that time."
       }
      }
     },
     "auth_ref": [
      "r0",
      "r383",
      "r542",
      "r562"
     ]
    },
    "ifrs-full_DividendsReceivedClassifiedAsOperatingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DividendsReceivedClassifiedAsOperatingActivities",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatementParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Dividends received, classified as operating activities",
        "label": "Dividends received, classified as operating activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash inflow from dividends received, classified as operating activities. [Refer: Dividends received]"
       }
      }
     },
     "auth_ref": [
      "r121"
     ]
    },
    "ifrs-full_DividendsRecognisedAsDistributionsToOwnersOfParentRelatingToCurrentYear": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DividendsRecognisedAsDistributionsToOwnersOfParentRelatingToCurrentYear",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Dividends, interim",
        "label": "Dividends recognised as distributions to owners of parent, relating to current year"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of dividends relating to the current year, recognised as distributions to owners of the parent. [Refer: Parent [member]]"
       }
      }
     },
     "auth_ref": [
      "r879"
     ]
    },
    "ifrs-full_DividendsRecognisedAsDistributionsToOwnersOfParentRelatingToPriorYears": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "DividendsRecognisedAsDistributionsToOwnersOfParentRelatingToPriorYears",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Dividends paid, relating to prior years",
        "label": "Dividends recognised as distributions to owners of parent, relating to prior years"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of dividends relating to prior years, recognised as distributions to owners of the parent. [Refer: Parent [member]]"
       }
      }
     },
     "auth_ref": [
      "r879"
     ]
    },
    "dei_DocumentAccountingStandard": {
     "xbrltype": "accountingStandardItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "DocumentAccountingStandard",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Document Accounting Standard",
        "label": "Document Accounting Standard",
        "documentation": "The basis of accounting the registrant has used to prepare the financial statements included in this filing This can either be 'U.S. GAAP', 'International Financial Reporting Standards', or 'Other'."
       }
      }
     },
     "auth_ref": [
      "r727"
     ]
    },
    "dei_DocumentAnnualReport": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "DocumentAnnualReport",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Document Annual Report",
        "label": "Document Annual Report",
        "documentation": "Boolean flag that is true only for a form used as an annual report."
       }
      }
     },
     "auth_ref": [
      "r726",
      "r727",
      "r750"
     ]
    },
    "dei_DocumentFinStmtErrorCorrectionFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "DocumentFinStmtErrorCorrectionFlag",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Document Financial Statement Error Correction [Flag]",
        "label": "Document Financial Statement Error Correction [Flag]",
        "documentation": "Indicates whether any of the financial statement period in the filing include a restatement due to error correction."
       }
      }
     },
     "auth_ref": [
      "r726",
      "r727",
      "r750",
      "r793"
     ]
    },
    "dei_DocumentFiscalPeriodFocus": {
     "xbrltype": "fiscalPeriodItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "DocumentFiscalPeriodFocus",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Document Fiscal Period Focus",
        "label": "Document Fiscal Period Focus",
        "documentation": "Fiscal period values are FY, Q1, Q2, and Q3. 1st, 2nd and 3rd quarter 10-Q or 10-QT statements have value Q1, Q2, and Q3 respectively, with 10-K, 10-KT or other fiscal year statements having FY."
       }
      }
     },
     "auth_ref": []
    },
    "dei_DocumentFiscalYearFocus": {
     "xbrltype": "gYearItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "DocumentFiscalYearFocus",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Document Fiscal Year Focus",
        "label": "Document Fiscal Year Focus",
        "documentation": "This is focus fiscal year of the document report in YYYY format. For a 2006 annual report, which may also provide financial information from prior periods, fiscal 2006 should be given as the fiscal year focus. Example: 2006."
       }
      }
     },
     "auth_ref": []
    },
    "dei_DocumentPeriodEndDate": {
     "xbrltype": "dateItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "DocumentPeriodEndDate",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Document Period End Date",
        "label": "Document Period End Date",
        "documentation": "For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD."
       }
      }
     },
     "auth_ref": []
    },
    "dei_DocumentRegistrationStatement": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "DocumentRegistrationStatement",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Document Registration Statement",
        "label": "Document Registration Statement",
        "documentation": "Boolean flag that is true only for a form used as a registration statement."
       }
      }
     },
     "auth_ref": [
      "r722"
     ]
    },
    "dei_DocumentShellCompanyReport": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "DocumentShellCompanyReport",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Document Shell Company Report",
        "label": "Document Shell Company Report",
        "documentation": "Boolean flag that is true for a Shell Company Report pursuant to section 13 or 15(d) of the Exchange Act."
       }
      }
     },
     "auth_ref": [
      "r727"
     ]
    },
    "dei_DocumentTransitionReport": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "DocumentTransitionReport",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Document Transition Report",
        "label": "Document Transition Report",
        "documentation": "Boolean flag that is true only for a form used as a transition report."
       }
      }
     },
     "auth_ref": [
      "r771"
     ]
    },
    "dei_DocumentType": {
     "xbrltype": "submissionTypeItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "DocumentType",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Document Type",
        "label": "Document Type",
        "documentation": "The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DocumentaryCreditsAndOtherShortTermTradeRelatedTransactions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DocumentaryCreditsAndOtherShortTermTradeRelatedTransactions",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails": {
       "parentTag": "bbplc_CommitmentsGiven",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Documentary credits and other short-term trade related transactions",
        "label": "Documentary Credits And Other Short-Term Trade Related Transactions"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DocumentaryCreditsAndOtherShortTermTradeRelatedTransactionsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DocumentaryCreditsAndOtherShortTermTradeRelatedTransactionsMember",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Documentary credits and other short-term trade related transactions",
        "label": "Documentary Credits And Other Short-Term Trade Related Transactions [Member]",
        "documentation": "This member stands for documentary credits and other short-term trade related transactions."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DownsideOneMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DownsideOneMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Downside 1",
        "label": "Downside 1 [member]",
        "documentation": "The downside 1 scenario. The adverse scenarios are calibrated to a similar severity to internal stress tests, whilst also considering IFRS 9 specific sensitivities and non-linearity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DownsideScenarioMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DownsideScenarioMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Downside scenario",
        "label": "Downside Scenario [Member]",
        "documentation": "Downside Scenario"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DownsideTwoMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DownsideTwoMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Downside 2",
        "label": "Downside 2 [member]",
        "documentation": "The downside 2 scenario. The adverse scenarios are calibrated to a similar severity to internal stress tests, whilst also considering IFRS 9 specific sensitivities and non-linearity. Downside 2 is benchmarked to the Bank of England's annual cyclical scenarios and to the most severe scenario from Moody's inventory, but is not designed to be the same. The Downside 2 scenario represents a severe global recession with substantial falls in both UK and US GDP. Unemployment in both markets rises towards 9% and there are substantial falls in asset prices including housing."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_DurationOfExpectedBenefitsAreProjectedToBePaidOut": {
     "xbrltype": "durationItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "DurationOfExpectedBenefitsAreProjectedToBePaidOut",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Duration of expected benefits are projected to be paid out",
        "label": "Duration Of Expected Benefits Are Projected To Be Paid Out",
        "documentation": "The duration of expected benefits are projected to be paid out."
       }
      }
     },
     "auth_ref": []
    },
    "ecd_DvddsOrOthrErngsPdOnEqtyAwrdsNtOthrwsRflctdInTtlCompForCvrdYrMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "DvddsOrOthrErngsPdOnEqtyAwrdsNtOthrwsRflctdInTtlCompForCvrdYrMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member]",
        "terseLabel": "Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year"
       }
      }
     },
     "auth_ref": [
      "r782"
     ]
    },
    "bbplc_EBITDAMultipleMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "EBITDAMultipleMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "EBITDA multiple",
        "label": "EBITDA Multiple, Measurement Input [Member]",
        "documentation": "EBITDA Multiple, Measurement Input"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ECLEconomicScenarioAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ECLEconomicScenarioAxis",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "ECL Economic Scenario [Axis]",
        "label": "ECL Economic Scenario [Axis]",
        "documentation": "ECL Economic Scenario"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ECLEconomicScenarioDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ECLEconomicScenarioDomain",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "ECL Economic Scenario [Domain]",
        "label": "ECL Economic Scenario [Domain]",
        "documentation": "ECL Economic Scenario [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ECLFromAssetsClassifiedAsHeldForSaleAdjustmentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ECLFromAssetsClassifiedAsHeldForSaleAdjustmentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "ECL from held for sale assets (co-branded card portfolio)",
        "label": "ECL From Assets Classified As Held For Sale, Adjustment [Member]",
        "documentation": "ECL From Assets Classified As Held For Sale, Adjustment"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ECLFromBenchmarkedExposuresAndOthersMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ECLFromBenchmarkedExposuresAndOthersMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "ECL from benchmarked exposures and others",
        "label": "ECL From Benchmarked Exposures And Others [Member]",
        "documentation": "This member stands for expected credit losses from non-modelled and other management adjustments."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ECLFromDebtSecuritiesAtAmortisedCostMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ECLFromDebtSecuritiesAtAmortisedCostMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "ECL from debt securities at amortised cost",
        "label": "ECL From Debt Securities At Amortised Cost [Member]",
        "documentation": "ECL From Debt Securities At Amortised Cost"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ECLFromPostModelManagementAdjustmentsEconomicUncertaintyAdjustmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ECLFromPostModelManagementAdjustmentsEconomicUncertaintyAdjustmentsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "ECL from economic uncertainty adjustments",
        "label": "ECL From Post-Model Management Adjustments, Economic Uncertainty Adjustments [Member]",
        "documentation": "ECL From Post-Model Management Adjustments, Economic Uncertainty Adjustments"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ECLFromPostModelManagementAdjustmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ECLFromPostModelManagementAdjustmentsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "ECL from post model management adjustments",
        "label": "ECL From Post-Model Management Adjustments [Member]",
        "documentation": "ECL From Post-Model Management Adjustments"
       }
      }
     },
     "auth_ref": []
    },
    "currency_EUR": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/currency/2025",
     "localname": "EUR",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "netLabel": "EUR",
        "verboseLabel": "EUR foreign operations",
        "label": "Euro Member Countries, Euro"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_EconomicUncertaintyAdjustmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "EconomicUncertaintyAdjustmentsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Economic uncertainty adjustments",
        "label": "Economic Uncertainty Adjustments [Member]",
        "documentation": "Management has applied Covid-19 specific adjustments to modelled outputs to ensure the full potential impacts of stress are provided for. These adjustments address the temporary nature of ongoing government support, the uncertainty in relation to the timing of stress and the degree to which economic consensus has yet captured the range of economic uncertainty, particularly in the UK."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_EffectOfExchangeRateChangesOnCashAndCashEquivalents": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "EffectOfExchangeRateChangesOnCashAndCashEquivalents",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_IncreaseDecreaseInCashAndCashEquivalents",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Effect of exchange rates on cash and cash equivalents",
        "label": "Effect of exchange rate changes on cash and cash equivalents"
       }
      },
      "en": {
       "role": {
        "documentation": "The effect of exchange rate changes on cash and cash equivalents held or due in a foreign currency. [Refer: Cash and cash equivalents]"
       }
      }
     },
     "auth_ref": [
      "r119",
      "r120"
     ]
    },
    "ifrs-full_EliminationOfIntersegmentAmountsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "EliminationOfIntersegmentAmountsMember",
     "presentation": [
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Of which inter-segmental income/(expense)",
        "label": "Elimination of intersegment amounts [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the elimination of intersegment amounts in the reconciliations of total segment amounts to amounts recognised in the entity's financial statements."
       }
      }
     },
     "auth_ref": [
      "r695",
      "r696"
     ]
    },
    "bbplc_EmployeeBenefitAndOtherTrustsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "EmployeeBenefitAndOtherTrustsMember",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Employee benefit and other trusts",
        "label": "Employee Benefit And Other Trusts [Member]",
        "documentation": "This member stands employee benefits and trust funds."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_EmployeeBenefitsExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "EmployeeBenefitsExpense",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_OperatingExpense",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/StaffcostsDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Staff costs",
        "totalLabel": "Total staff costs",
        "label": "Employee benefits expense"
       }
      }
     },
     "auth_ref": [
      "r375",
      "r549",
      "r605",
      "r716"
     ]
    },
    "us-gaap_EmployeeStockOptionMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/us-gaap/2025",
     "localname": "EmployeeStockOptionMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Employee Stock Option [Member]",
        "terseLabel": "Employee Stock Option"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_EnergyAndWaterMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "EnergyAndWaterMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Energy and water",
        "label": "Energy And Water [Member]",
        "documentation": "This member stands for the energy and water industry."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressAddressLine1": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityAddressAddressLine1",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Address, Address Line One",
        "label": "Entity Address, Address Line One",
        "documentation": "Address Line 1 such as Attn, Building Name, Street Name"
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressCityOrTown": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityAddressCityOrTown",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Address, City or Town",
        "label": "Entity Address, City or Town",
        "documentation": "Name of the City or Town"
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressCountry": {
     "xbrltype": "countryCodeItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityAddressCountry",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Address, Country",
        "label": "Entity Address, Country",
        "documentation": "ISO 3166-1 alpha-2 country code."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressPostalZipCode": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityAddressPostalZipCode",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Address, Postal Zip Code",
        "label": "Entity Address, Postal Zip Code",
        "documentation": "Code for the postal or zip code"
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityAddressesAddressTypeAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityAddressesAddressTypeAxis",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Addresses, Address Type [Axis]",
        "label": "Entity Addresses, Address Type [Axis]",
        "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityCentralIndexKey": {
     "xbrltype": "centralIndexKeyItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityCentralIndexKey",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Central Index Key",
        "label": "Entity Central Index Key",
        "documentation": "A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK."
       }
      }
     },
     "auth_ref": [
      "r724"
     ]
    },
    "dei_EntityCommonStockSharesOutstanding": {
     "xbrltype": "sharesItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityCommonStockSharesOutstanding",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Common Stock, Shares Outstanding",
        "label": "Entity Common Stock, Shares Outstanding",
        "documentation": "Indicate number of shares or other units outstanding of each of registrant's classes of capital or common stock or other ownership interests, if and as stated on cover of related periodic report. Where multiple classes or units exist define each class/interest by adding class of stock items such as Common Class A [Member], Common Class B [Member] or Partnership Interest [Member] onto the Instrument [Domain] of the Entity Listings, Instrument."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityCurrentReportingStatus": {
     "xbrltype": "yesNoItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityCurrentReportingStatus",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Current Reporting Status",
        "label": "Entity Current Reporting Status",
        "documentation": "Indicate 'Yes' or 'No' whether registrants (1) have filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that registrants were required to file such reports), and (2) have been subject to such filing requirements for the past 90 days. This information should be based on the registrant's current or most recent filing containing the related disclosure."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityEmergingGrowthCompany": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityEmergingGrowthCompany",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Emerging Growth Company",
        "label": "Entity Emerging Growth Company",
        "documentation": "Indicate if registrant meets the emerging growth company criteria."
       }
      }
     },
     "auth_ref": [
      "r724"
     ]
    },
    "dei_EntityFileNumber": {
     "xbrltype": "fileNumberItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityFileNumber",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity File Number",
        "label": "Entity File Number",
        "documentation": "Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityFilerCategory": {
     "xbrltype": "filerCategoryItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityFilerCategory",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Filer Category",
        "label": "Entity Filer Category",
        "documentation": "Indicate whether the registrant is one of the following: Large Accelerated Filer, Accelerated Filer, Non-accelerated Filer. Definitions of these categories are stated in Rule 12b-2 of the Exchange Act. This information should be based on the registrant's current or most recent filing containing the related disclosure."
       }
      }
     },
     "auth_ref": [
      "r724"
     ]
    },
    "dei_EntityIncorporationStateCountryCode": {
     "xbrltype": "edgarStateCountryItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityIncorporationStateCountryCode",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Incorporation, State or Country Code",
        "label": "Entity Incorporation, State or Country Code",
        "documentation": "Two-character EDGAR code representing the state or country of incorporation."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityInteractiveDataCurrent": {
     "xbrltype": "yesNoItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityInteractiveDataCurrent",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Interactive Data Current",
        "label": "Entity Interactive Data Current",
        "documentation": "Boolean flag that is true when the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit such files)."
       }
      }
     },
     "auth_ref": [
      "r833"
     ]
    },
    "dei_EntityListingsLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityListingsLineItems",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Listings [Line Items]",
        "label": "Entity Listings [Line Items]",
        "documentation": "Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityListingsTable": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityListingsTable",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Listings [Table]",
        "label": "Entity Listings [Table]",
        "documentation": "Container for exchange listing information for an entity"
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityRegistrantName": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityRegistrantName",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Registrant Name",
        "label": "Entity Registrant Name",
        "documentation": "The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC."
       }
      }
     },
     "auth_ref": [
      "r724"
     ]
    },
    "dei_EntityShellCompany": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityShellCompany",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Shell Company",
        "label": "Entity Shell Company",
        "documentation": "Boolean flag that is true when the registrant is a shell company as defined in Rule 12b-2 of the Exchange Act."
       }
      }
     },
     "auth_ref": [
      "r724"
     ]
    },
    "dei_EntityVoluntaryFilers": {
     "xbrltype": "yesNoItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityVoluntaryFilers",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Voluntary Filers",
        "label": "Entity Voluntary Filers",
        "documentation": "Indicate 'Yes' or 'No' if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act."
       }
      }
     },
     "auth_ref": []
    },
    "dei_EntityWellKnownSeasonedIssuer": {
     "xbrltype": "yesNoItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "EntityWellKnownSeasonedIssuer",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Entity Well-known Seasoned Issuer",
        "label": "Entity Well-known Seasoned Issuer",
        "documentation": "Indicate 'Yes' or 'No' if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Is used on Form Type: 10-K, 10-Q, 8-K, 20-F, 6-K, 10-K/A, 10-Q/A, 20-F/A, 6-K/A, N-CSR, N-Q, N-1A."
       }
      }
     },
     "auth_ref": [
      "r834"
     ]
    },
    "ecd_EqtyAwrdsAdjFnTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "EqtyAwrdsAdjFnTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Equity Awards Adjustments, Footnote [Text Block]",
        "terseLabel": "Equity Awards Adjustments, Footnote"
       }
      }
     },
     "auth_ref": [
      "r776"
     ]
    },
    "ecd_EqtyAwrdsAdjsExclgValRprtdInSummryCompstnTblMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "EqtyAwrdsAdjsExclgValRprtdInSummryCompstnTblMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member]",
        "terseLabel": "Equity Awards Adjustments, Excluding Value Reported in Compensation Table"
       }
      }
     },
     "auth_ref": [
      "r829"
     ]
    },
    "ecd_EqtyAwrdsAdjsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "EqtyAwrdsAdjsMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Equity Awards Adjustments [Member]",
        "terseLabel": "Equity Awards Adjustments"
       }
      }
     },
     "auth_ref": [
      "r829"
     ]
    },
    "ecd_EqtyAwrdsInSummryCompstnTblForAplblYrMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "EqtyAwrdsInSummryCompstnTblForAplblYrMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member]",
        "terseLabel": "Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table"
       }
      }
     },
     "auth_ref": [
      "r829"
     ]
    },
    "bbplc_EquistoneFounderPartnerIIIL.P.Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "EquistoneFounderPartnerIIIL.P.Member",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Equistone Founder Partner III L.P.",
        "label": "Equistone Founder Partner III L.P. [Member]",
        "documentation": "Equistone Founder Partner III L.P."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_Equity": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "Equity",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_EquityAndLiabilities",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total equity",
        "periodStartLabel": "Beginning balance, equity",
        "periodEndLabel": "Ending balance, equity",
        "terseLabel": "Equity",
        "label": "Equity"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of residual interest in the assets of the entity after deducting all its liabilities."
       }
      }
     },
     "auth_ref": [
      "r130",
      "r132",
      "r162",
      "r163",
      "r170",
      "r429",
      "r459",
      "r530",
      "r531",
      "r543",
      "r575",
      "r581"
     ]
    },
    "ifrs-full_EquityAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "EquityAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Equity",
        "label": "Equity [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_EquityAndLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "EquityAndLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total liabilities and equity",
        "label": "Equity and liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of the entity's equity and liabilities. [Refer: Equity; Liabilities]"
       }
      }
     },
     "auth_ref": [
      "r575"
     ]
    },
    "ifrs-full_EquityInstrumentsAmountContributedToFairValueOfPlanAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "EquityInstrumentsAmountContributedToFairValueOfPlanAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails": {
       "parentTag": "ifrs-full_PlanAssetsAtFairValue",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Equity instruments",
        "verboseLabel": "Equities",
        "label": "Equity instruments, amount contributed to fair value of plan assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount instruments representing equity (rather than debt) contribute to the fair value of defined benefit plan assets. [Refer: Plan assets, at fair value; Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r614",
      "r702"
     ]
    },
    "ifrs-full_EquityInstrumentsHeld": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "EquityInstrumentsHeld",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails": {
       "parentTag": "ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLoss",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Equity securities",
        "label": "Equity instruments held"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of instruments held by the entity that provide evidence of a residual interest in the assets of another entity after deducting all of its liabilities."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_EquityInvestmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "EquityInvestmentsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Equities",
        "label": "Equity investments [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for investments in equity instruments."
       }
      }
     },
     "auth_ref": [
      "r671",
      "r691"
     ]
    },
    "srt_EquityMethodInvesteeNameDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "EquityMethodInvesteeNameDomain",
     "presentation": [
      "http://www.home.barclays/role/AcquisitionandDisposalsofsubsidiariesDetails",
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails",
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Investment, Name [Domain]",
        "label": "Investment, Name [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_EquityPriceRiskMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "EquityPriceRiskMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Equity risk",
        "terseLabel": "Equity and stock index derivatives",
        "netLabel": "Equity derivatives",
        "label": "Equity price risk [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a component of other price risk that represents the type of risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in equity prices. [Refer: Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r670",
      "r690"
     ]
    },
    "ecd_EquityValuationAssumptionDifferenceFnTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "EquityValuationAssumptionDifferenceFnTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Equity Valuation Assumption Difference, Footnote [Text Block]",
        "terseLabel": "Equity Valuation Assumption Difference, Footnote"
       }
      }
     },
     "auth_ref": [
      "r786"
     ]
    },
    "ecd_ErrCompAnalysisTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "ErrCompAnalysisTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Erroneous Compensation Analysis [Text Block]",
        "terseLabel": "Erroneous Compensation Analysis"
       }
      }
     },
     "auth_ref": [
      "r743",
      "r754",
      "r764",
      "r797"
     ]
    },
    "ecd_ErrCompRecoveryTable": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "ErrCompRecoveryTable",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Erroneously Awarded Compensation Recovery [Table]",
        "terseLabel": "Erroneously Awarded Compensation Recovery"
       }
      }
     },
     "auth_ref": [
      "r740",
      "r751",
      "r761",
      "r794"
     ]
    },
    "ifrs-full_EstimateOfContributionsExpectedToBePaidToPlan": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "EstimateOfContributionsExpectedToBePaidToPlan",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Estimate of contributions expected to be paid to plan for next annual reporting period",
        "label": "Estimate of contributions expected to be paid to plan for next annual reporting period"
       }
      },
      "en": {
       "role": {
        "documentation": "The estimate of the expected contributions to be made to a defined benefit plan for the next annual reporting period. [Refer: Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r36",
      "r38",
      "r415"
     ]
    },
    "ifrs-full_EstimatedFinancialEffectOfContingentLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "EstimatedFinancialEffectOfContingentLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails": {
       "parentTag": "bbplc_CommitmentsGiven",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Contingent liabilities and financial guarantees",
        "label": "Estimated financial effect of contingent liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of the estimated financial effect of contingent liabilities. [Refer: Classes of contingent liabilities [domain]]"
       }
      }
     },
     "auth_ref": [
      "r97",
      "r447"
     ]
    },
    "srt_EuropeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "EuropeMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Europe",
        "label": "Europe [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ExchangeDifferencesOnTranslationAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExchangeDifferencesOnTranslationAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Currency translation reserve",
        "label": "Exchange differences on translation [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ExchangeTradedDerivativesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ExchangeTradedDerivativesMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Exchange traded derivatives",
        "label": "Exchange Traded Derivatives [Member]",
        "documentation": "An exchange traded derivative is a financial contract that is listed and trades on a regulated exchange."
       }
      }
     },
     "auth_ref": []
    },
    "ecd_ExecutiveCategoryAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "ExecutiveCategoryAxis",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Executive Category [Axis]",
        "terseLabel": "Executive Category:"
       }
      }
     },
     "auth_ref": [
      "r792"
     ]
    },
    "bbplc_ExitPriceAdjustmentsDerivedFromMarketBidOfferSpreadsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ExitPriceAdjustmentsDerivedFromMarketBidOfferSpreadsMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureoffairvalueadjustmentsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Exit price adjustments derived from market bid-offer spreads",
        "label": "Exit Price Adjustments Derived From Market Bid-Offer Spreads [Member]",
        "documentation": "This member stands for exit price adjustments derived from market bid-offer spreads. The methodology for determining the bid-offer adjustment for a derivative portfolio involves calculating the net risk exposure by offsetting long and short positions by strike and term in accordance with the risk management and hedging strategy."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ExpectedCreditLossRate": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExpectedCreditLossRate",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Expected credit loss rate",
        "verboseLabel": "ECL coverage",
        "label": "Expected credit loss rate"
       }
      },
      "en": {
       "role": {
        "documentation": "The rate of expected credit losses, calculated as percentage of the gross carrying amount. Expected credit losses are the weighted average of credit losses with the respective risks of a default occurring as the weights."
       }
      }
     },
     "auth_ref": [
      "r669",
      "r688"
     ]
    },
    "ifrs-full_ExpectedCreditLossesCollectivelyAssessedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExpectedCreditLossesCollectivelyAssessedMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "ECL collectively assessed",
        "verboseLabel": "Total weighted model ECL",
        "label": "Expected credit losses collectively assessed [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for expected credit losses that are collectively assessed. [Refer: Method of assessment of expected credit losses [domain]]"
       }
      }
     },
     "auth_ref": [
      "r662",
      "r667",
      "r686",
      "r707",
      "r712"
     ]
    },
    "ifrs-full_ExpectedCreditLossesIndividuallyAssessedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExpectedCreditLossesIndividuallyAssessedMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "ECL from individually assessed impairments",
        "verboseLabel": "ECL from individually assessed exposures",
        "label": "Expected credit losses individually assessed [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for expected credit losses that are individually assessed. [Refer: Method of assessment of expected credit losses [domain]]"
       }
      }
     },
     "auth_ref": [
      "r662",
      "r667",
      "r686",
      "r707",
      "r712"
     ]
    },
    "bbplc_ExpectedCreditLossesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ExpectedCreditLossesMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "ECL",
        "label": "Expected Credit Losses [Member]",
        "documentation": "This member stands for the expected credit losses that result from default events on a financial instrument that are possible within the 12 months after the reporting date and all possible default events over the expected life of a financial instrument."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ExpectedDividendAsPercentageShareOptionsGranted": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExpectedDividendAsPercentageShareOptionsGranted",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Pure dividend yield rates",
        "label": "Expected dividend as percentage, share options granted"
       }
      },
      "en": {
       "role": {
        "documentation": "The percentage of an expected dividend used to calculate the fair value of share options granted."
       }
      }
     },
     "auth_ref": [
      "r224"
     ]
    },
    "ifrs-full_ExpectedReimbursementOtherProvisions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExpectedReimbursementOtherProvisions",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Expected reimbursement",
        "label": "Expected reimbursement, other provisions"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount expected to be reimbursed by another party on expenditures to settle other provisions. [Refer: Other provisions]"
       }
      }
     },
     "auth_ref": [
      "r96",
      "r446"
     ]
    },
    "ifrs-full_ExpenseByNatureAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExpenseByNatureAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Expenses by nature [abstract]",
        "label": "Expenses by nature [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ExpenseFromCashsettledSharebasedPaymentTransactionsInWhichGoodsOrServicesReceivedDidNotQualifyForRecognitionAsAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExpenseFromCashsettledSharebasedPaymentTransactionsInWhichGoodsOrServicesReceivedDidNotQualifyForRecognitionAsAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofsharebasedpaymentschemesDetails": {
       "parentTag": "ifrs-full_ExpenseFromSharebasedPaymentTransactionsInWhichGoodsOrServicesReceivedDidNotQualifyForRecognitionAsAssets",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofsharebasedpaymentschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash settled",
        "label": "Expense from cash-settled share-based payment transactions"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "ifrs-full_ExpenseFromEquitysettledSharebasedPaymentTransactionsInWhichGoodsOrServicesReceivedDidNotQualifyForRecognitionAsAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExpenseFromEquitysettledSharebasedPaymentTransactionsInWhichGoodsOrServicesReceivedDidNotQualifyForRecognitionAsAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofsharebasedpaymentschemesDetails": {
       "parentTag": "ifrs-full_ExpenseFromSharebasedPaymentTransactionsInWhichGoodsOrServicesReceivedDidNotQualifyForRecognitionAsAssets",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofsharebasedpaymentschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total equity settled",
        "label": "Expense from equity-settled share-based payment transactions"
       }
      }
     },
     "auth_ref": [
      "r226"
     ]
    },
    "ifrs-full_ExpenseFromSharebasedPaymentTransactionsInWhichGoodsOrServicesReceivedDidNotQualifyForRecognitionAsAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExpenseFromSharebasedPaymentTransactionsInWhichGoodsOrServicesReceivedDidNotQualifyForRecognitionAsAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofsharebasedpaymentschemesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofsharebasedpaymentschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total Share-based payments",
        "label": "Expense from share-based payment transactions"
       }
      }
     },
     "auth_ref": [
      "r226",
      "r470"
     ]
    },
    "ifrs-full_ExpenseOfRestructuringActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExpenseOfRestructuringActivities",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/StaffcostsDetails": {
       "parentTag": "bbplc_ResourcingCosts",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Redundancy and restructuring",
        "label": "Expense of restructuring activities"
       }
      }
     },
     "auth_ref": [
      "r602"
     ]
    },
    "ifrs-full_ExpenseRelatingToVariableLeasePaymentsNotIncludedInMeasurementOfLeaseLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExpenseRelatingToVariableLeasePaymentsNotIncludedInMeasurementOfLeaseLiabilities",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/LeasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Expense relating to variable lease payments not included in measurement of lease liabilities",
        "label": "Expense relating to variable lease payments not included in measurement of lease liabilities"
       }
      }
     },
     "auth_ref": [
      "r191",
      "r364"
     ]
    },
    "ifrs-full_ExplanationOfCreditRiskManagementPracticesAndHowTheyRelateToRecognitionAndMeasurementOfExpectedCreditLossesExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExplanationOfCreditRiskManagementPracticesAndHowTheyRelateToRecognitionAndMeasurementOfExpectedCreditLossesExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of concentrations of credit risk by industry and geography",
        "label": "Explanation of credit risk management practices and how they relate to recognition and measurement of expected credit losses [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The explanation of the credit risk management practices and how they relate to the recognition and measurement of expected credit losses."
       }
      }
     },
     "auth_ref": [
      "r280"
     ]
    },
    "ifrs-full_ExplanationOfInputsAssumptionsAndEstimationTechniquesUsedToApplyImpairmentRequirementsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExplanationOfInputsAssumptionsAndEstimationTechniquesUsedToApplyImpairmentRequirementsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of ECL under 100% weighted scenarios for key modelled portfolios",
        "label": "Explanation of inputs, assumptions and estimation techniques used to apply impairment requirements [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The explanation of the inputs, assumptions and estimation techniques used to apply the impairment requirements for financial instruments."
       }
      }
     },
     "auth_ref": [
      "r281",
      "r507"
     ]
    },
    "ifrs-full_ExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "periodStartLabel": "Opening/Beginning balance",
        "periodEndLabel": "Closing/Ending balance",
        "terseLabel": "Exposure to credit risk on loan commitments and financial guarantee contracts",
        "label": "Exposure to credit risk on loan commitments and financial guarantee contracts"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of the exposure to credit risk on loan commitments and financial guarantee contracts. [Refer: Loan commitments [member]; Financial guarantee contracts [member]; Credit risk [member]]"
       }
      }
     },
     "auth_ref": [
      "r285",
      "r286",
      "r296",
      "r511",
      "r513",
      "r517"
     ]
    },
    "bbplc_ExternalCustomersMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ExternalCustomersMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Bank PLC externally issued",
        "label": "External Customers [Member]",
        "documentation": "This member stands for external customers of the entity."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FairValueHedgesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FairValueHedgesMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fair value hedges",
        "label": "Fair value hedges [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for hedges of the exposure to changes in fair value of a recognised asset or liability or an unrecognised firm commitment, or an identified portion of such an asset, liability or firm commitment, that is attributable to a particular risk and could affect profit or loss. [Refer: Types of hedges [domain]]"
       }
      }
     },
     "auth_ref": [
      "r108",
      "r259",
      "r267",
      "r271",
      "r494",
      "r499",
      "r503"
     ]
    },
    "bbplc_FairValueMortgageLoansMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FairValueMortgageLoansMember",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Mortgage Loans",
        "label": "Fair Value Mortgage Loans [Member]",
        "documentation": "Fair Value Mortgage Loans"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FairValueOfAssetsRepresentingContinuingInvolvementInDerecognisedFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FairValueOfAssetsRepresentingContinuingInvolvementInDerecognisedFinancialAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureofcontinuinginvolvementinfinancialassetsthathavebeenderecognisedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fair value",
        "label": "Fair value of assets representing continuing involvement in derecognised financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The fair value of assets representing the entity's continuing involvement in derecognised financial assets. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r305"
     ]
    },
    "ifrs-full_FairValueOfAssociatedFinancialLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FairValueOfAssociatedFinancialLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails": {
       "parentTag": "ifrs-full_FairValueOfTransferredFinancialAssetsAssociatedFinancialLiabilitiesThatAreNotDerecognisedInTheirEntirety",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Liabilities, fair value",
        "negatedTerseLabel": "Associated liabilities, fair value",
        "label": "Fair value of associated financial liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The fair value of financial liabilities associated with transferred financial assets that are not derecognised in their entirety. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r300"
     ]
    },
    "ifrs-full_FairValueOfTransferredFinancialAssetsAssociatedFinancialLiabilitiesThatAreNotDerecognisedInTheirEntirety": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FairValueOfTransferredFinancialAssetsAssociatedFinancialLiabilitiesThatAreNotDerecognisedInTheirEntirety",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Net position",
        "label": "Fair value of transferred financial assets (associated financial liabilities) that are not derecognised in their entirety"
       }
      },
      "en": {
       "role": {
        "documentation": "The difference between the fair value of transferred financial assets that have not been derecognised in their entirety and their associated liabilities. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r300"
     ]
    },
    "ifrs-full_FairValueOfTransferredFinancialAssetsThatAreNotDerecognisedInTheirEntirety": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FairValueOfTransferredFinancialAssetsThatAreNotDerecognisedInTheirEntirety",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails": {
       "parentTag": "ifrs-full_FairValueOfTransferredFinancialAssetsAssociatedFinancialLiabilitiesThatAreNotDerecognisedInTheirEntirety",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets, fair value",
        "verboseLabel": "Transferred assets, fair value",
        "label": "Fair value of transferred financial assets that are not derecognised in their entirety"
       }
      },
      "en": {
       "role": {
        "documentation": "The fair value of transferred financial assets that are not derecognised in their entirety. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r300"
     ]
    },
    "bbplc_FederalFundsRateMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FederalFundsRateMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Federal funds rate",
        "label": "Federal Funds Rate [Member]",
        "documentation": "This member stands for Federal funds rate."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FeeAndCommissionExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FeeAndCommissionExpense",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_FeeAndCommissionIncomeExpense",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Fee and commission expense",
        "label": "Fee and commission expense"
       }
      }
     },
     "auth_ref": [
      "r887"
     ]
    },
    "ifrs-full_FeeAndCommissionIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FeeAndCommissionIncome",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_FeeAndCommissionIncomeExpense",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fee and commission income",
        "totalLabel": "Fee and commission income",
        "label": "Fee and commission income"
       }
      }
     },
     "auth_ref": [
      "r887"
     ]
    },
    "ifrs-full_FeeAndCommissionIncomeAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FeeAndCommissionIncomeAbstract",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fee and commission income [abstract]",
        "label": "Fee and commission income [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FeeAndCommissionIncomeExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FeeAndCommissionIncomeExpense",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "bbplc_OperatingIncome",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Net fee and commission income",
        "label": "Fee and commission income (expense)"
       }
      }
     },
     "auth_ref": [
      "r887"
     ]
    },
    "ifrs-full_FeeAndCommissionIncomeExpenseAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FeeAndCommissionIncomeExpenseAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fee and commission income (expense) [abstract]",
        "label": "Fee and commission income (expense) [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails",
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans and advances",
        "periodStartLabel": "Opening/Beginning balance",
        "periodEndLabel": "Closing/Ending balance",
        "negatedLabel": "Financial assets",
        "negatedTerseLabel": "Loans and advances",
        "verboseLabel": "Credit exposure",
        "totalLabel": "Total financial assets",
        "label": "Financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of assets that are: (a) cash; (b) an equity instrument of another entity; (c) a contractual right: (i) to receive cash or another financial asset from another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially favourable to the entity; or (d) a contract that will, or may be, settled in the entity\u2019s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to receive a variable number of the entity\u2019s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity\u2019s own equity instruments. For this purpose the entity\u2019s own equity instruments do not include puttable financial instruments classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity\u2019s own equity instruments. [Refer: Classes of financial instruments [domain]; Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r274",
      "r285",
      "r286",
      "r296",
      "r511",
      "r513",
      "r517",
      "r669"
     ]
    },
    "ifrs-full_FinancialAssetsAtAmortisedCostCategoryMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsAtAmortisedCostCategoryMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails",
      "http://www.home.barclays/role/SecuritisationsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Financial assets at amortised cost",
        "terseLabel": "Total loans\u00a0and\u00a0advances at amortised cost",
        "label": "Financial assets at amortised cost, category [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the financial assets at amortised cost category. [Refer: Financial assets at amortised cost]"
       }
      }
     },
     "auth_ref": [
      "r317",
      "r478"
     ]
    },
    "ifrs-full_FinancialAssetsAtAmortisedCostMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsAtAmortisedCostMember",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets at amortised cost",
        "label": "Financial assets at amortised cost, class [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the financial assets measured at amortised cost class. [Refer: Financial assets at amortised cost]"
       }
      }
     },
     "auth_ref": [
      "r323",
      "r353",
      "r489"
     ]
    },
    "ifrs-full_FinancialAssetsAtFairValue": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsAtFairValue",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total assets",
        "periodStartLabel": "Beginning balance, financial assets",
        "periodEndLabel": "Ending balance, financial assets",
        "label": "Financial assets, at fair value"
       }
      },
      "en": {
       "role": {
        "documentation": "The fair value of financial assets. [Refer: At fair value [member]; Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r274"
     ]
    },
    "ifrs-full_FinancialAssetsAtFairValueThroughOtherComprehensiveIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsAtFairValueThroughOtherComprehensiveIncome",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails": {
       "parentTag": "ifrs-full_FinancialAssetsAtFairValue",
       "weight": 1.0,
       "order": 4.0
      },
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 4.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 10.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialAssets",
       "weight": 1.0,
       "order": 10.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughothercomprehensiveincomeDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets at fair value through other comprehensive income",
        "label": "Financial assets at fair value through other comprehensive income"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial assets at fair value through other comprehensive income. [Refer: At fair value [member]; Financial assets; Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r318",
      "r480"
     ]
    },
    "ifrs-full_FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets at fair value through other comprehensive income [abstract]",
        "label": "Financial assets at fair value through other comprehensive income [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeCategoryMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsAtFairValueThroughOtherComprehensiveIncomeCategoryMember",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcarryingamountoftheassetspledgedassecurityagainstliabilitiesDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets at fair value through other comprehensive income",
        "verboseLabel": "Fair value through other comprehensive income",
        "label": "Financial assets at fair value through other comprehensive income, category [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the financial assets at fair value through other comprehensive income category. [Refer: Financial assets at fair value through other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r318",
      "r480"
     ]
    },
    "ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLoss": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsAtFairValueThroughProfitOrLoss",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails": {
       "parentTag": "ifrs-full_FinancialAssetsAtFairValue",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialAssets",
       "weight": 1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 7.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 8.0
      },
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Financial assets at fair value through the income statement",
        "netLabel": "Financial assets at fair value through the income statement",
        "totalLabel": "Financial assets at fair value through profit or loss",
        "terseLabel": "Total financial assets at fair value through the income statement",
        "label": "Financial assets at fair value through profit or loss"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial assets that are measured at fair value and for which gains (losses) are recognised in profit or loss. A financial asset shall be measured at fair value through profit or loss unless it is measured at amortised cost or at fair value through other comprehensive income. A gain (loss) on a financial asset measured at fair value shall be recognised in profit or loss unless it is part of a hedging relationship, it is an investment in an equity instrument for which the entity has elected to present gains and losses in other comprehensive income or it is a financial asset measured at fair value through other comprehensive income. [Refer: At fair value [member]; Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r315",
      "r475"
     ]
    },
    "ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLossAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsAtFairValueThroughProfitOrLossAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets at fair value through profit or loss [abstract]",
        "label": "Financial assets at fair value through profit or loss [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLossCategoryMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsAtFairValueThroughProfitOrLossCategoryMember",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcarryingamountoftheassetspledgedassecurityagainstliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total financial assets at fair value through the income statement",
        "verboseLabel": "Financial assets at fair value through the income statement",
        "netLabel": "Financial assets at FVTPL",
        "label": "Financial assets at fair value through profit or loss, category [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the financial assets at fair value through profit or loss category. [Refer: Financial assets at fair value through profit or loss]"
       }
      }
     },
     "auth_ref": [
      "r315",
      "r475"
     ]
    },
    "bbplc_FinancialAssetsAtFairValueThroughProfitOrLossCategoryOtherIncomeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialAssetsAtFairValueThroughProfitOrLossCategoryOtherIncomeMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets at fair value through profit or loss, category other income",
        "label": "Financial Assets At Fair Value Through Profit Or Loss, Category Other Income [Member]",
        "documentation": "This member stands for the financial assets at fair value through profit or loss category, located in other income. [Refer: Financial liabilities at fair value through profit or loss]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_FinancialAssetsAtFairValueThroughProfitOrLossCategoryTradingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialAssetsAtFairValueThroughProfitOrLossCategoryTradingMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets at fair value through profit or loss, category trading",
        "label": "Financial Assets At Fair Value Through Profit Or Loss, Category Trading [Member]",
        "documentation": "This member stands for the financial assets at fair value through profit or loss category, located in trading income. [Refer: Financial liabilities at fair value through profit or loss]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails": {
       "parentTag": "ifrs-full_FinancialAssetsAtFairValue",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialAssets",
       "weight": 1.0,
       "order": 5.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 6.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 7.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails",
      "http://www.home.barclays/role/TradingportfolioDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Trading portfolio assets",
        "terseLabel": "Trading portfolio assets",
        "label": "Financial assets at fair value through profit or loss, classified as held for trading"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial assets at fair value through profit or loss classified as held for trading. A financial asset is classified as held for trading if: (a) it is acquired principally for the purpose of selling it in the near term; (b) on initial recognition it is part of a portfolio of identified financial instruments that are managed together and for which there is evidence of a recent actual pattern of short-term profit-taking; or (c) it is a derivative (except for a derivative that is a financial guarantee contract or a designated and effective hedging instrument). [Refer: At fair value [member]; Financial assets at fair value through profit or loss, mandatorily measured at fair value]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTradingCategoryMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTradingCategoryMember",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcarryingamountoftheassetspledgedassecurityagainstliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/NettradingincomeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total trading portfolio assets",
        "verboseLabel": "Net gains on financial instruments held for trading",
        "netLabel": "Trading portfolio assets",
        "label": "Financial assets at fair value through profit or loss, classified as held for trading, category [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the financial assets at fair value through profit or loss classified as held for trading category. [Refer: Financial assets at fair value through profit or loss, classified as held for trading]"
       }
      }
     },
     "auth_ref": [
      "r546"
     ]
    },
    "bbplc_FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTradingPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialAssetsAtFairValueThroughProfitOrLossClassifiedAsHeldForTradingPercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Trading portfolio assets, percentage",
        "label": "Financial Assets At Fair Value Through Profit Or Loss, Classified As Held For Trading, Percentage",
        "documentation": "The amount of financial assets at fair value through profit or loss classified as held for trading, expressed as a percentage. A financial asset is classified as held for trading if: (a) it is acquired principally for the purpose of selling it in the near term; (b) on initial recognition it is part of a portfolio of identified financial instruments that are managed together and for which there is evidence of a recent actual pattern of short-term profit-taking; or (c) it is a derivative (except for a derivative that is a financial guarantee contract or a designated and effective hedging instrument). [Refer: At fair value [member]; Financial assets at fair value through profit or loss]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLossDesignatedUponInitialRecognitionCategoryMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsAtFairValueThroughProfitOrLossDesignatedUponInitialRecognitionCategoryMember",
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/NettradingincomeDetails",
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net gains on financial instruments designated at fair value",
        "verboseLabel": "Financial assets designated at fair value",
        "label": "Financial assets at fair value through profit or loss, designated upon initial recognition or subsequently, category [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the financial assets at fair value through profit or loss designated as such upon initial recognition or subsequently category. [Refer: Financial assets at fair value through profit or loss, designated upon initial recognition or subsequently]"
       }
      }
     },
     "auth_ref": [
      "r315"
     ]
    },
    "ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLossMandatorilyMeasuredAtFairValueCategoryMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsAtFairValueThroughProfitOrLossMandatorilyMeasuredAtFairValueCategoryMember",
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/NettradingincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net gains on financial instruments mandatorily at fair value",
        "verboseLabel": "Financial assets mandatorily at fair value",
        "label": "Financial assets at fair value through profit or loss, mandatorily measured at fair value, category [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the financial assets mandatorily measured at fair value through profit or loss category. [Refer: Financial assets at fair value through profit or loss, mandatorily measured at fair value]"
       }
      }
     },
     "auth_ref": [
      "r315"
     ]
    },
    "bbplc_FinancialAssetsAtFairValueThroughProfitOrLossPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialAssetsAtFairValueThroughProfitOrLossPercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets at fair value through the income statement, percentage",
        "label": "Financial Assets At Fair Value Through Profit Or Loss, Percentage",
        "documentation": "The amount of financial assets (expressed as a percentage) that are measured at fair value and for which gains (losses) are recognised in profit or loss. A financial asset shall be measured at fair value through profit or loss unless it is measured at amortised cost or at fair value through other comprehensive income. A gain (loss) on a financial asset measured at fair value shall be recognised in profit or loss unless it is part of a hedging relationship, it is an investment in an equity instrument for which the entity has elected to present gains and losses in other comprehensive income or it is a financial asset measured at fair value through other comprehensive income. [Refer: At fair value [member]; Financial assets]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 9.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets at fair value through other comprehensive income",
        "label": "Financial assets measured at fair value through other comprehensive income"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial assets that are measured at fair value through other comprehensive income. A financial asset shall be measured at fair value through other comprehensive income if both of the following conditions are met: (a) the financial asset is held within a business model whose objective is achieved by both collecting contractual cash flows and selling financial assets and (b) the contractual terms of the financial asset give rise on specified dates to cash flows that are solely payments of principal and interest on the principal amount outstanding. [Refer: At fair value [member]; Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r318",
      "r479"
     ]
    },
    "ifrs-full_FinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fair value through other comprehensive income reserve movement relating to debt securities",
        "label": "Financial assets measured at fair value through other comprehensive income [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeCategoryMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeCategoryMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial instruments at fair value through other comprehensive income",
        "label": "Financial assets measured at fair value through other comprehensive income, category [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the financial assets at fair value through other comprehensive income category. [Refer: Financial assets measured at fair value through other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r318",
      "r479"
     ]
    },
    "bbplc_FinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomePercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomePercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets measured at fair value through other comprehensive income, percentage",
        "label": "Financial Assets Measured At Fair Value Through Other Comprehensive Income, Percentage",
        "documentation": "The amount (expressed as a percentage) of financial assets that are measured at fair value through other comprehensive income. A financial asset shall be measured at fair value through other comprehensive income if both of the following conditions are met: (a) the financial asset is held within a business model whose objective is achieved by both collecting contractual cash flows and selling financial assets and (b) the contractual terms of the financial asset give rise on specified dates to cash flows that are solely payments of principal and interest on the principal amount outstanding. [Refer: At fair value [member]; Financial assets]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_FinancialAssetsNotSubjectToEnforceableMasterNettingArrangementOrSimilarAgreement": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialAssetsNotSubjectToEnforceableMasterNettingArrangementOrSimilarAgreement",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": "ifrs-full_ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Amounts not subject to enforceable netting arrangements",
        "label": "Financial Assets Not Subject To Enforceable Master Netting Arrangement Or Similar Agreement",
        "documentation": "The financial assets that are not subject to an enforceable master netting arrangement or similar agreement."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FinancialAssetsPledgedAsCollateralForLiabilitiesOrContingentLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsPledgedAsCollateralForLiabilitiesOrContingentLiabilities",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcarryingamountoftheassetspledgedassecurityagainstliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets pledged",
        "label": "Financial assets pledged as collateral for liabilities or contingent liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial assets that the entity has pledged as collateral for liabilities or contingent liabilities, including amounts that have been reclassified in accordance with paragraph 3.2.23(a) of IFRS 9. [Refer: Classes of contingent liabilities [domain]; Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r244",
      "r485"
     ]
    },
    "bbplc_FinancialAssetsSubjectToOffsettingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialAssetsSubjectToOffsettingMember",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total assets",
        "label": "Financial Assets Subject To Offsetting [Member]",
        "documentation": "Financial Assets Subject To Offsetting"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FinancialAssetsWhichDoNotQualifyForDerecognitionAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsWhichDoNotQualifyForDerecognitionAxis",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails",
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureoftransferredfinancialassetsandtheassociatedliabilitiesDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails",
      "http://www.home.barclays/role/SecuritisationsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Transferred financial assets that are not derecognised in their entirety [axis]",
        "label": "Transferred financial assets that are not derecognised in their entirety [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r303",
      "r521"
     ]
    },
    "ifrs-full_FinancialAssetsWhichDoNotQualifyForDerecognitionDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsWhichDoNotQualifyForDerecognitionDomain",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails",
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureoftransferredfinancialassetsandtheassociatedliabilitiesDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails",
      "http://www.home.barclays/role/SecuritisationsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Transferred financial assets that are not derecognised in their entirety [domain]",
        "verboseLabel": "Transferred financial assets that are not derecognised in their entirety [domain]",
        "label": "Transferred financial assets that are not derecognised in their entirety [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for transferred financial assets that are not derecognised in their entirety. It also represents the standard value for the 'Transferred financial assets that are not derecognised in their entirety' axis if no other member is used. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r303",
      "r521"
     ]
    },
    "ifrs-full_FinancialAssetsWithContractualCashFlowsModifiedDuringReportingPeriodWhileLossAllowanceMeasuredAtLifetimeExpectedCreditLossesAmortisedCostBeforeModification": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsWithContractualCashFlowsModifiedDuringReportingPeriodWhileLossAllowanceMeasuredAtLifetimeExpectedCreditLossesAmortisedCostBeforeModification",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Amortised cost before modification",
        "label": "Financial assets with contractual cash flows modified during reporting period while loss allowance measured at lifetime expected credit losses, amortised cost before modification"
       }
      },
      "en": {
       "role": {
        "documentation": "The amortised cost before the modification of financial assets for which the contractual cash flows have been modified during the reporting period while they had a loss allowance measured at an amount equal to lifetime expected credit losses. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r287"
     ]
    },
    "ifrs-full_FinancialAssetsWithContractualCashFlowsModifiedDuringReportingPeriodWhileLossAllowanceMeasuredAtLifetimeExpectedCreditLossesModificationGainLoss": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsWithContractualCashFlowsModifiedDuringReportingPeriodWhileLossAllowanceMeasuredAtLifetimeExpectedCreditLossesModificationGainLoss",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Net modification loss",
        "label": "Financial assets with contractual cash flows modified during reporting period while loss allowance measured at lifetime expected credit losses, modification gain (loss)"
       }
      },
      "en": {
       "role": {
        "documentation": "The net modification gain (loss) on financial assets for which the contractual cash flows have been modified during the reporting period while they had a loss allowance measured at an amount equal to lifetime expected credit losses. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r287"
     ]
    },
    "ifrs-full_FinancialAssetsWithModifiedContractualCashFlowsWhileLossAllowanceMeasuredAtLifetimeExpectedCreditLossesForWhichLossAllowanceChangedDuringReportingPeriodTo12monthExpectedCreditLossesGrossCarryingAmount": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsWithModifiedContractualCashFlowsWhileLossAllowanceMeasuredAtLifetimeExpectedCreditLossesForWhichLossAllowanceChangedDuringReportingPeriodTo12monthExpectedCreditLossesGrossCarryingAmount",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Carrying amount of financial assets for which loss allowance has changed to 12-month measurement",
        "label": "Financial assets with modified contractual cash flows while loss allowance measured at lifetime expected credit losses for which loss allowance changed during reporting period to 12-month expected credit losses, gross carrying amount"
       }
      },
      "en": {
       "role": {
        "documentation": "The gross carrying amount of financial assets that have been modified since initial recognition at a time when the loss allowance was measured at an amount equal to lifetime expected credit losses and for which the loss allowance has changed during the reporting period to an amount equal to 12-month expected credit losses. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r288"
     ]
    },
    "ifrs-full_FinancialAssetsWrittenOffDuringReportingPeriodAndStillSubjectToEnforcementActivityContractualAmountOutstanding": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialAssetsWrittenOffDuringReportingPeriodAndStillSubjectToEnforcementActivityContractualAmountOutstanding",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial assets written and subject to enforcement activity, contractual amount outstanding",
        "label": "Financial assets written off during reporting period and still subject to enforcement activity, contractual amount outstanding"
       }
      },
      "en": {
       "role": {
        "documentation": "The contractual amount outstanding on financial assets that were written off during the reporting period and are still subject to enforcement activity. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r292"
     ]
    },
    "bbplc_FinancialCollateralPledgedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialCollateralPledgedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements",
       "weight": -1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial collateral",
        "label": "Financial Collateral Pledged Subject To Enforceable Master Netting Arrangement Or Similar Agreement Not Set Off Against Financial Liabilities",
        "documentation": "The amount of financial collateral pledged that is subject to an enforceable master netting arrangement or similar agreement and that is not set off against financial liabilities. [Refer: Financial liabilities]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_FinancialCollateralReceivedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialCollateralReceivedSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssets",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements",
       "weight": -1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Financial collateral",
        "label": "Financial Collateral Received Subject To Enforceable Master Netting Arrangement Or Similar Agreement Not Set Off Against Financial Assets",
        "documentation": "The amount of financial collateral received that is subject to an enforceable master netting arrangement or similar agreement and that is not set off against financial assets. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FinancialForecastOfCashFlowsForCashgeneratingUnitMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialForecastOfCashFlowsForCashgeneratingUnitMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Cash flows",
        "label": "Financial forecast of cash inflows (outflows) for cash-generating unit, measurement input [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a financial forecast of cash flows for a cash-generating unit, used as a measurement input."
       }
      }
     },
     "auth_ref": [
      "r647"
     ]
    },
    "ifrs-full_FinancialGuaranteeContractsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialGuaranteeContractsMember",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial guarantee contracts",
        "verboseLabel": "Contingent liabilities and financial guarantees",
        "label": "Financial guarantee contracts [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for contracts that require the issuer to make specified payments to reimburse the holder for a loss it incurs because a specified debtor fails to make payment when due in accordance with the original or modified terms of a debt instrument."
       }
      }
     },
     "auth_ref": [
      "r296",
      "r326",
      "r512",
      "r517"
     ]
    },
    "bbplc_FinancialInstrumentWhichHedgeNetInvestmentsHedges": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialInstrumentWhichHedgeNetInvestmentsHedges",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial instrument which hedge net investments",
        "label": "Financial Instrument Which Hedge Net Investments, Hedges",
        "documentation": "Financial Instrument Which Hedge Net Investments, Hedges"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_FinancialInstrumentsAtAmortisedCostCategoryMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialInstrumentsAtAmortisedCostCategoryMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial instruments at amortised cost",
        "label": "Financial Instruments At Amortised Cost, Category [Member]",
        "documentation": "This member stands for the financial instruments carried at amortised cost category."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_FinancialInstrumentsAtFairValueCategoryMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialInstrumentsAtFairValueCategoryMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial instruments at fair value",
        "label": "Financial Instruments At Fair Value, Category [Member]",
        "documentation": "This member stands for the financial instruments measured at fair value."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FinancialInstrumentsCreditimpairedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialInstrumentsCreditimpairedMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Credit-impaired",
        "terseLabel": "Stage 3",
        "label": "Financial instruments credit-impaired [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for financial instruments that are credit-impaired. [Refer: Credit impairment of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r285",
      "r296",
      "r511",
      "r517"
     ]
    },
    "ifrs-full_FinancialInstrumentsNotCreditimpairedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialInstrumentsNotCreditimpairedMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Stage 2",
        "label": "Financial instruments not credit-impaired [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for financial instruments that are not credit-impaired. [Refer: Credit impairment of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r285",
      "r296",
      "r511",
      "r517"
     ]
    },
    "ifrs-full_FinancialInstrumentsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialInstrumentsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialAssets",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails": {
       "parentTag": "bbplc_NetExposureToCreditRisk",
       "weight": -1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Netting and set-off",
        "negatedLabel": "Financial instruments",
        "label": "Financial instruments subject to enforceable master netting arrangement or similar agreement not set off against financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial instruments subject to an enforceable master netting arrangement or similar agreement that are not set off against financial assets. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r658",
      "r692"
     ]
    },
    "ifrs-full_FinancialInstrumentsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialInstrumentsSubjectToEnforceableMasterNettingArrangementOrSimilarAgreementNotSetOffAgainstFinancialLiabilities",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial instruments",
        "label": "Financial instruments subject to enforceable master netting arrangement or similar agreement not set off against financial liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial instruments subject to an enforceable master netting arrangement or similar agreement that are not set off against financial liabilities. [Refer: Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r658",
      "r692"
     ]
    },
    "ifrs-full_FinancialLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total financial liabilities",
        "label": "Financial liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of liabilities that are: (a) a contractual obligation: (i) to deliver cash or another financial asset to another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially unfavourable to the entity; or (b) a contract that will, or may be, settled in the entity\u2019s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to deliver a variable number of the entity\u2019s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity\u2019s own equity instruments. For this purpose, rights, options or warrants to acquire a fixed number of the entity\u2019s own equity instruments for a fixed amount of any currency are equity instruments if the entity offers the rights, options or warrants pro rata to all of its existing owners of the same class of its own non-derivative equity instruments. Also, for those purposes the entity\u2019s own equity instruments do not include puttable financial instruments that are classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity\u2019s own equity instruments. As an exception, an instrument that meets the definition of a financial liability is classified as an equity instrument if it has all the features and meets the conditions in paragraphs 16A-16B or paragraphs 16C-16D of IAS 32. [Refer: Classes of financial instruments [domain]; Financial assets; Derivatives [member]]"
       }
      }
     },
     "auth_ref": [
      "r274"
     ]
    },
    "ifrs-full_FinancialLiabilitiesAtAmortisedCostMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialLiabilitiesAtAmortisedCostMember",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial liabilities at amortised cost",
        "label": "Financial liabilities at amortised cost, class [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the financial liabilities measured at amortised cost class. [Refer: Financial liabilities at amortised cost]"
       }
      }
     },
     "auth_ref": [
      "r323",
      "r353",
      "r489"
     ]
    },
    "ifrs-full_FinancialLiabilitiesAtFairValue": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialLiabilitiesAtFairValue",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTotalLabel": "Total liabilities",
        "negatedPeriodStartLabel": "Beginning balance, financial liabilities",
        "negatedPeriodEndLabel": "Ending balance, financial liabilities",
        "label": "Financial liabilities, at fair value"
       }
      },
      "en": {
       "role": {
        "documentation": "The fair value of financial liabilities. [Refer: At fair value [member]; Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r274"
     ]
    },
    "ifrs-full_FinancialLiabilitiesAtFairValueMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialLiabilitiesAtFairValueMember",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial liabilities at fair value",
        "label": "Financial liabilities at fair value, class [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the financial liabilities measured at fair value class. [Refer: Financial liabilities; At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r323"
     ]
    },
    "bbplc_FinancialLiabilitiesAtFairValueThroughProfitOrLossCategoryOtherIncomeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialLiabilitiesAtFairValueThroughProfitOrLossCategoryOtherIncomeMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial liabilities at fair value through profit or loss, category other income",
        "label": "Financial Liabilities At Fair Value Through Profit Or Loss, Category Other Income [Member]",
        "documentation": "This member stands for the financial liabilities at fair value through profit or loss category, located in other income. [Refer: Financial liabilities at fair value through profit or loss]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_FinancialLiabilitiesAtFairValueThroughProfitOrLossCategoryTradingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialLiabilitiesAtFairValueThroughProfitOrLossCategoryTradingMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial liabilities at fair value through profit or loss, category trading",
        "label": "Financial Liabilities At Fair Value Through Profit Or Loss, Category Trading [Member]",
        "documentation": "This member stands for the financial liabilities at fair value through profit or loss category, located in trading income. [Refer: Financial liabilities at fair value through profit or loss]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FinancialLiabilitiesAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialLiabilitiesAtFairValueThroughProfitOrLossClassifiedAsHeldForTrading",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails": {
       "parentTag": "ifrs-full_FinancialLiabilitiesAtFairValue",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 7.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialLiabilities",
       "weight": 1.0,
       "order": 8.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TradingportfolioDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Trading portfolio liabilities",
        "negatedLabel": "Trading Portfolio Liabilities",
        "label": "Financial liabilities at fair value through profit or loss that meet definition of held for trading"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial liabilities at fair value through profit or loss that meet the definition of held for trading. A financial liability is classified as held for trading if: (a) it is acquired or incurred principally for the purpose of selling or repurchasing it in the near term; (b) on initial recognition it is part of a portfolio of identified financial instruments that are managed together and for which there is evidence of a recent actual pattern of short-term profit-taking; or (c) it is a derivative (except for a derivative that is a financial guarantee contract or a designated and effective hedging instrument). [Refer: Financial liabilities at fair value through profit or loss]"
       }
      }
     },
     "auth_ref": [
      "r316",
      "r477"
     ]
    },
    "ifrs-full_FinancialLiabilitiesAtFairValueThroughProfitOrLossDesignatedAsUponInitialRecognition": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialLiabilitiesAtFairValueThroughProfitOrLossDesignatedAsUponInitialRecognition",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails": {
       "parentTag": "ifrs-full_FinancialLiabilitiesAtFairValue",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialLiabilities",
       "weight": 1.0,
       "order": 7.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 8.0
      },
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial liabilities designated at fair value",
        "totalLabel": "Financial liabilities designated at fair value",
        "negatedLabel": "Financial liabilities designated at fair value",
        "label": "Financial liabilities at fair value through profit or loss, designated upon initial recognition or subsequently"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial liabilities at fair value through profit or loss that were designated as such upon initial recognition or subsequently. [Refer: At fair value [member]; Financial liabilities at fair value through profit or loss]"
       }
      }
     },
     "auth_ref": [
      "r316",
      "r476"
     ]
    },
    "ifrs-full_FinancialLiabilitiesAtFairValueThroughProfitOrLossDesignatedUponInitialRecognitionCategoryMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialLiabilitiesAtFairValueThroughProfitOrLossDesignatedUponInitialRecognitionCategoryMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/NettradingincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Liabilities designated at fair value",
        "verboseLabel": "Financial liabilities designated at fair value",
        "label": "Financial liabilities at fair value through profit or loss, designated upon initial recognition or subsequently, category [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the financial liabilities at fair value through profit or loss designated as such upon initial recognition or subsequently category. [Refer: Financial liabilities at fair value through profit or loss, designated upon initial recognition or subsequently]"
       }
      }
     },
     "auth_ref": [
      "r316",
      "r476"
     ]
    },
    "bbplc_FinancialLiabilitiesAtFairValueThroughProfitOrLossDesignatedUponInitialRecognitionOrSubsequentlyUndiscountedCashFlows": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialLiabilitiesAtFairValueThroughProfitOrLossDesignatedUponInitialRecognitionOrSubsequentlyUndiscountedCashFlows",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails": {
       "parentTag": "bbplc_TotalFinancialLiabilitiesUndiscounted",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial liabilities designated at fair value, undiscounted",
        "label": "Financial Liabilities At Fair Value Through Profit Or Loss, Designated Upon Initial Recognition Or Subsequently, Undiscounted Cash Flows",
        "documentation": "The amount of contractual undiscounted cash flows in relation to financial liabilities at fair value through profit or loss, designated upon initial recognition or subsequently."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FinancialLiabilitiesAtFairValueThroughProfitOrLossThatMeetDefinitionOfHeldForTradingCategoryMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FinancialLiabilitiesAtFairValueThroughProfitOrLossThatMeetDefinitionOfHeldForTradingCategoryMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/NettradingincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Liabilities held for trading",
        "terseLabel": "Trading portfolio liabilities",
        "label": "Financial liabilities at fair value through profit or loss that meet definition of held for trading, category [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the financial liabilities at fair value through profit or loss that meet the definition of held for trading category. [Refer: Financial liabilities at fair value through profit or loss that meet definition of held for trading]"
       }
      }
     },
     "auth_ref": [
      "r316",
      "r477"
     ]
    },
    "bbplc_FinancialLiabilitiesAtFairValueThroughProfitOrLossThatMeetDefinitionOfHeldForTradingUndiscountedCashFlows": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialLiabilitiesAtFairValueThroughProfitOrLossThatMeetDefinitionOfHeldForTradingUndiscountedCashFlows",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails": {
       "parentTag": "bbplc_TotalFinancialLiabilitiesUndiscounted",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Trading portfolio liabilities, undiscounted",
        "label": "Financial Liabilities At Fair Value Through Profit Or Loss That Meet Definition Of Held For Trading, Undiscounted Cash Flows",
        "documentation": "The amount of contractual undiscounted cash flows in relation to financial liabilities at fair value through profit or loss that meet definition of held for trading."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_FinancialLiabilitiesSubjectToOffsettingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialLiabilitiesSubjectToOffsettingMember",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total liabilities",
        "label": "Financial Liabilities Subject To Offsetting [Member]",
        "documentation": "Financial Liabilities Subject To Offsetting"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_FinancialStatementLocationAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialStatementLocationAxis",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial statement location [Axis]",
        "label": "Financial Statement Location [Axis]",
        "documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_FinancialStatementLocationMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FinancialStatementLocationMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Financial statement location [Member]",
        "label": "Financial Statement Location [Member]",
        "documentation": "This member stands for the financial statement location. It also represents the standard value for the 'Financial statement location' axis if no other member is used."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_FiveYearAveragesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FiveYearAveragesMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "5-year averages",
        "label": "Five Year Averages [Member]",
        "documentation": "Average basis represents the average quarterly value of variables in the 20 quarter period with GDP and HPI based on yearly average and quarterly CAGRs respectively."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_FixedAssetTimingDifferencesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FixedAssetTimingDifferencesMember",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fixed asset timing differences",
        "label": "Fixed Asset Timing Differences [Member]",
        "documentation": "This member stands for fixed asset timing differences."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FixedInterestRateMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FixedInterestRateMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fixed interest rate",
        "label": "Fixed interest rate [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a fixed interest rate. [Refer: Interest rate risk [member]]"
       }
      }
     },
     "auth_ref": [
      "r873"
     ]
    },
    "bbplc_FixedRateResettingPerpetualSubordinatedContingentConvertibleSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FixedRateResettingPerpetualSubordinatedContingentConvertibleSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fixed rate resetting contingent convertible securities",
        "label": "Fixed Rate Resetting Perpetual Subordinated Contingent Convertible Securities [member]",
        "documentation": "This member stands for the Fixed Rate Resetting Perpetual Subordinated Contingent Convertible Securities of the entity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_FixedToFloatingInterestRateMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FixedToFloatingInterestRateMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fixed-to-Floating Interest Rate",
        "label": "Fixed-To-Floating Interest Rate [Member]",
        "documentation": "This member stands for the conversion of interest rates from fixed to floating interest rate."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_FixturesAndFittingsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FixturesAndFittingsMember",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fixtures and fittings and other equipment",
        "label": "Fixtures and fittings [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a class of property, plant and equipment representing fixtures and fittings that are not permanently attached to real property. [Refer: Property, plant and equipment]"
       }
      }
     },
     "auth_ref": [
      "r609"
     ]
    },
    "ifrs-full_FloatingInterestRateMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "FloatingInterestRateMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Floating interest rate",
        "label": "Floating interest rate [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a non-fixed interest rate. [Refer: Interest rate risk [member]]"
       }
      }
     },
     "auth_ref": [
      "r873"
     ]
    },
    "ifrs-full_ForeignCountriesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ForeignCountriesMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Foreign countries",
        "label": "Foreign countries [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for countries outside the entity's country of domicile. [Refer: Country of domicile [member]]"
       }
      }
     },
     "auth_ref": [
      "r343",
      "r344"
     ]
    },
    "bbplc_ForeignCurrencyNetInvestmentsHedgedItem": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ForeignCurrencyNetInvestmentsHedgedItem",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails": {
       "parentTag": "bbplc_StructuralCurrencyExposureBeforeHedgingInstruments",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Foreign currency net investments",
        "label": "Foreign Currency Net Investments, Hedged Item",
        "documentation": "The amount of foreign currency net investments."
       }
      }
     },
     "auth_ref": []
    },
    "ecd_ForgoneRecoveryDueToDisqualificationOfTaxBenefitsAmt": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "ForgoneRecoveryDueToDisqualificationOfTaxBenefitsAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Forgone Recovery due to Disqualification of Tax Benefits, Amount",
        "terseLabel": "Forgone Recovery due to Disqualification of Tax Benefits, Amount"
       }
      }
     },
     "auth_ref": [
      "r747",
      "r758",
      "r768",
      "r801"
     ]
    },
    "ecd_ForgoneRecoveryDueToExpenseOfEnforcementAmt": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "ForgoneRecoveryDueToExpenseOfEnforcementAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Forgone Recovery due to Expense of Enforcement, Amount",
        "terseLabel": "Forgone Recovery due to Expense of Enforcement, Amount"
       }
      }
     },
     "auth_ref": [
      "r747",
      "r758",
      "r768",
      "r801"
     ]
    },
    "ecd_ForgoneRecoveryDueToViolationOfHomeCountryLawAmt": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "ForgoneRecoveryDueToViolationOfHomeCountryLawAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Forgone Recovery due to Violation of Home Country Law, Amount",
        "terseLabel": "Forgone Recovery due to Violation of Home Country Law, Amount"
       }
      }
     },
     "auth_ref": [
      "r747",
      "r758",
      "r768",
      "r801"
     ]
    },
    "ecd_ForgoneRecoveryExplanationOfImpracticabilityTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "ForgoneRecoveryExplanationOfImpracticabilityTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Forgone Recovery, Explanation of Impracticability [Text Block]",
        "terseLabel": "Forgone Recovery, Explanation of Impracticability"
       }
      }
     },
     "auth_ref": [
      "r747",
      "r758",
      "r768",
      "r801"
     ]
    },
    "ecd_ForgoneRecoveryIndName": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "ForgoneRecoveryIndName",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Forgone Recovery, Individual Name",
        "terseLabel": "Name"
       }
      }
     },
     "auth_ref": [
      "r747",
      "r758",
      "r768",
      "r801"
     ]
    },
    "ecd_FrValAsOfPrrYrEndOfEqtyAwrdsGrntdInPrrYrsFldVstngCondsDrngCvrdYrMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "FrValAsOfPrrYrEndOfEqtyAwrdsGrntdInPrrYrsFldVstngCondsDrngCvrdYrMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member]",
        "terseLabel": "Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year"
       }
      }
     },
     "auth_ref": [
      "r781"
     ]
    },
    "bbplc_FullyLoadedCommonEquityTierOneCapitalMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "FullyLoadedCommonEquityTierOneCapitalMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcapitalresourcesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "CET1 capital",
        "label": "Fully Loaded Common Equity Tier One Capital [Member]",
        "documentation": "This member stands for the fully loaded CRD IV CET1 ratio. It is a measure of the capital strength and resilience of the entity."
       }
      }
     },
     "auth_ref": []
    },
    "country_GB": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/country/2025",
     "localname": "GB",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "UK",
        "terseLabel": "United Kingdom",
        "label": "UNITED KINGDOM"
       }
      }
     },
     "auth_ref": []
    },
    "currency_GBP": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/currency/2025",
     "localname": "GBP",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "GBP",
        "verboseLabel": "GBP",
        "label": "United Kingdom, Pounds"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_GainLossArisingFromDerecognitionOfFinancialAssetsMeasuredAtAmortisedCost": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainLossArisingFromDerecognitionOfFinancialAssetsMeasuredAtAmortisedCost",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails": {
       "parentTag": "bbplc_NetInvestmentIncomeExpense",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net losses from disposals of financial assets and liabilities measured at amortised cost",
        "label": "Gain (loss) arising from derecognition of financial assets measured at amortised cost"
       }
      },
      "en": {
       "role": {
        "documentation": "The gain (loss) arising from the derecognition of financial assets measured at amortised cost. [Refer: Financial assets at amortised cost]"
       }
      }
     },
     "auth_ref": [
      "r594"
     ]
    },
    "ifrs-full_GainLossOfDerecognisedFinancialAssetsAtDateOfTransfer": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainLossOfDerecognisedFinancialAssetsAtDateOfTransfer",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureofcontinuinginvolvementinfinancialassetsthathavebeenderecognisedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Gain from continuing involvement, cumulative to 31 December",
        "label": "Gain (loss) of derecognised financial assets at date of transfer"
       }
      },
      "en": {
       "role": {
        "documentation": "The gain (loss) recognised on derecognised financial assets as of the date of the transfer of the assets. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r309"
     ]
    },
    "ifrs-full_GainLossOfDerecognisedFinancialAssetsRepresentingGreatestTransferActivity": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainLossOfDerecognisedFinancialAssetsRepresentingGreatestTransferActivity",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureofcontinuinginvolvementinfinancialassetsthathavebeenderecognisedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Gain from continuing involvement, for the year ended",
        "label": "Gain (loss) from transfer activity during period representing greatest transfer activity"
       }
      },
      "en": {
       "role": {
        "documentation": "The gain (loss) recognised from the transfer of financial assets during the part of the reporting period within which the greatest transfer activity took place when the total amount of proceeds from the transfer activity (that qualifies for derecognition) is not evenly distributed throughout the reporting period. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r310"
     ]
    },
    "ifrs-full_GainLossOnChangeInFairValueOfHedgedItemUsedAsBasisForRecognisingHedgeIneffectiveness": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainLossOnChangeInFairValueOfHedgedItemUsedAsBasisForRecognisingHedgeIneffectiveness",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Change in fair value used as a basis to determine ineffectiveness",
        "label": "Gain (loss) on change in fair value of hedged item used as basis for recognising hedge ineffectiveness"
       }
      },
      "en": {
       "role": {
        "documentation": "The gain (loss) on the change in fair value of the hedged item used as a basis for recognising hedge ineffectiveness. Hedge ineffectiveness is the extent to which the changes in the fair value or the cash flows of the hedging instrument are greater or less than those on the hedged item."
       }
      }
     },
     "auth_ref": [
      "r262",
      "r264",
      "r497",
      "r498"
     ]
    },
    "ifrs-full_GainLossOnChangeInFairValueOfHedgingInstrumentUsedAsBasisForRecognisingHedgeIneffectiveness": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainLossOnChangeInFairValueOfHedgingInstrumentUsedAsBasisForRecognisingHedgeIneffectiveness",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Change in fair value used as a basis to determine ineffectiveness",
        "label": "Gain (loss) on change in fair value of hedging instrument used as basis for recognising hedge ineffectiveness"
       }
      },
      "en": {
       "role": {
        "documentation": "The gain (loss) on the change in fair value of the hedging instrument used as a basis for recognising hedge ineffectiveness. Hedge ineffectiveness is the extent to which the changes in the fair value or the cash flows of the hedging instrument are greater or less than those on the hedged item."
       }
      }
     },
     "auth_ref": [
      "r257",
      "r492"
     ]
    },
    "ifrs-full_GainLossOnHedgeIneffectivenessRecognisedInOtherComprehensiveIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainLossOnHedgeIneffectivenessRecognisedInOtherComprehensiveIncome",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Hedging gains or losses recognised in other comprehensive income",
        "label": "Gain (loss) on hedge ineffectiveness recognised in other comprehensive income"
       }
      }
     },
     "auth_ref": [
      "r268",
      "r500"
     ]
    },
    "ifrs-full_GainLossOnHedgeIneffectivenessRecognisedInProfitOrLoss": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainLossOnHedgeIneffectivenessRecognisedInProfitOrLoss",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Hedge ineffectiveness recognised in the income statement",
        "label": "Gain (loss) on hedge ineffectiveness recognised in profit or loss"
       }
      }
     },
     "auth_ref": [
      "r268",
      "r269",
      "r500",
      "r501"
     ]
    },
    "ifrs-full_GainLossRecognisedOnMeasurementToFairValueLessCostsToSellOrOnDisposalOfAssetsOrDisposalGroupsConstitutingDiscontinuedOperation": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainLossRecognisedOnMeasurementToFairValueLessCostsToSellOrOnDisposalOfAssetsOrDisposalGroupsConstitutingDiscontinuedOperation",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "bbplc_ProfitLossFromOperatingActivitiesBeforeImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
       "weight": 1.0,
       "order": 4.0
      },
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement": {
       "parentTag": "bbplc_ProfitLossFromOperatingActivitiesBeforeImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loss on disposal of subsidiaries, associates and joint ventures",
        "verboseLabel": "Profit on disposal of subsidiaries, associates and joint ventures",
        "label": "Gain (loss) recognised on measurement to fair value less costs to sell or on disposal of assets or disposal groups constituting discontinued operation"
       }
      }
     },
     "auth_ref": [
      "r233"
     ]
    },
    "ifrs-full_GainOnRecoveryOfLoansAndAdvancesPreviouslyWrittenOff": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainOnRecoveryOfLoansAndAdvancesPreviouslyWrittenOff",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Post write-off recoveries",
        "verboseLabel": "Gain on recovery of loans and advances previously written off",
        "label": "Gain on recovery of loans and advances previously written off"
       }
      }
     },
     "auth_ref": [
      "r887"
     ]
    },
    "ifrs-full_GainsLossesArisingFromSettlementsNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainsLossesArisingFromSettlementsNetDefinedBenefitLiabilityAsset",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Settlements",
        "label": "Decrease (increase) in net defined benefit liability (asset) resulting from gains (losses) arising from settlements"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease (increase) in the net defined benefit liability (asset) resulting from settlements. Settlements are transactions that eliminate all further legal or constructive obligations for part or all of the benefits provided under a defined benefit plan, other than a payment of benefits to, or on behalf of, employees that is set out in the terms of the plan and included in the actuarial assumptions. [Refer: Net defined benefit liability (asset); Defined benefit plans [domain]; Actuarial assumptions [domain]]"
       }
      }
     },
     "auth_ref": [
      "r28"
     ]
    },
    "ifrs-full_GainsLossesOnCashFlowHedgesBeforeTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainsLossesOnCashFlowHedgesBeforeTax",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": 1.0,
       "order": 7.0
      },
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": 1.0,
       "order": 8.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net gains/(losses) from changes in fair value",
        "verboseLabel": "Net gains/(losses) from changes in fair value",
        "label": "Gains (losses) on cash flow hedges, before tax"
       }
      },
      "en": {
       "role": {
        "documentation": "The gains (losses) recognised in other comprehensive income on cash flow hedges, before tax, before reclassification adjustments. [Refer: Cash flow hedges [member]]"
       }
      }
     },
     "auth_ref": [
      "r599"
     ]
    },
    "bbplc_GainsLossesOnCashFlowHedgesExcludingExchangeDifferencesBeforeTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "GainsLossesOnCashFlowHedgesExcludingExchangeDifferencesBeforeTax",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectonthereservesasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Hedging (losses)/gains for the year",
        "label": "Gains (Losses) On Cash Flow Hedges Excluding Exchange Differences, Before Tax",
        "documentation": "Gains (Losses) On Cash Flow Hedges Excluding Exchange Differences, Before Tax"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_GainsLossesOnDisposalsOfInvestments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainsLossesOnDisposalsOfInvestments",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/AcquisitionandDisposalsofsubsidiariesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Gains (losses) on disposals of investments",
        "label": "Gains (losses) on disposals of investments"
       }
      },
      "en": {
       "role": {
        "documentation": "The gains (losses) on disposals of investments."
       }
      }
     },
     "auth_ref": [
      "r603"
     ]
    },
    "bbplc_GainsLossesOnExchangeDifferencesOnCashFlowHedgesBeforeTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "GainsLossesOnExchangeDifferencesOnCashFlowHedgesBeforeTax",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectonthereservesasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Currency translation movements",
        "label": "Gains (Losses) On Exchange Differences On Cash Flow Hedges, Before Tax",
        "documentation": "Gains (Losses) On Exchange Differences On Cash Flow Hedges, Before Tax"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_GainsLossesOnExchangeDifferencesOnTranslationBeforeTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainsLossesOnExchangeDifferencesOnTranslationBeforeTax",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectonthereservesasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Currency translation movements",
        "label": "Gains (losses) on exchange differences on translation of foreign operations, before tax"
       }
      },
      "en": {
       "role": {
        "documentation": "The gains (losses) recognised in other comprehensive income on exchange differences on the translation of financial statements of foreign operations, before tax, before reclassification adjustments. [Refer: Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r599"
     ]
    },
    "ifrs-full_GainsLossesOnFinancialAssetsAtFairValueThroughProfitOrLossMandatorilyMeasuredAtFairValue": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainsLossesOnFinancialAssetsAtFairValueThroughProfitOrLossMandatorilyMeasuredAtFairValue",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails": {
       "parentTag": "bbplc_NetInvestmentIncomeExpense",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net gains from financial assets mandatorily at fair value",
        "label": "Gains (losses) on financial assets at fair value through profit or loss, mandatorily measured at fair value"
       }
      }
     },
     "auth_ref": [
      "r247"
     ]
    },
    "ifrs-full_GainsLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainsLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTax",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net gains/(losses) from changes in fair value",
        "verboseLabel": "Net gains/(losses) from changes in fair value",
        "label": "Gains (losses) on financial assets measured at fair value through other comprehensive income, before tax"
       }
      },
      "en": {
       "role": {
        "documentation": "The gains (losses) recognised in other comprehensive income on financial assets measured at fair value through other comprehensive income applying paragraph 4.1.2A of IFRS 9, before tax, before reclassification adjustments. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r249",
      "r487",
      "r599"
     ]
    },
    "ifrs-full_GainsLossesOnFinancialInstrumentsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainsLossesOnFinancialInstrumentsAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Gains (losses) on financial instruments [abstract]",
        "label": "Gains (losses) on financial instruments [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_GainsLossesOnHedgesOfNetInvestmentsInForeignOperationsBeforeTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainsLossesOnHedgesOfNetInvestmentsInForeignOperationsBeforeTax",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectonthereservesasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Hedging (losses)/gains for the year",
        "label": "Gains (losses) on hedges of net investments in foreign operations, before tax"
       }
      },
      "en": {
       "role": {
        "documentation": "The gains (losses) recognised in other comprehensive income on hedges of net investments in foreign operations, before tax, before reclassification adjustments. [Refer: Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r106",
      "r349",
      "r599"
     ]
    },
    "ifrs-full_GainsLossesRecognisedInOtherComprehensiveIncomeFairValueMeasurementAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainsLossesRecognisedInOtherComprehensiveIncomeFairValueMeasurementAssets",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total gains or losses recognised in OCI, assets",
        "label": "Gains (losses) recognised in other comprehensive income including exchange differences, fair value measurement, assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The gains (losses) including exchange differences recognised in other comprehensive income on the fair value measurement of assets. [Refer: At fair value [member]; Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r167",
      "r533"
     ]
    },
    "ifrs-full_GainsLossesRecognisedInOtherComprehensiveIncomeFairValueMeasurementLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainsLossesRecognisedInOtherComprehensiveIncomeFairValueMeasurementLiabilities",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total gains or losses recognised in OCI, liabilities",
        "label": "Gains (losses) recognised in other comprehensive income including exchange differences, fair value measurement, liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The gains (losses) including exchange differences recognised in other comprehensive income on the fair value measurement of liabilities. [Refer: At fair value [member]; Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r167",
      "r533"
     ]
    },
    "bbplc_GainsLossesRecognisedInOtherComprehensiveIncomeIncludingExchangeDifferencesFairValueMeasurementAssetsLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "GainsLossesRecognisedInOtherComprehensiveIncomeIncludingExchangeDifferencesFairValueMeasurementAssetsLiabilities",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Gains (losses) recognised in other comprehensive income, fair value measurement, assets (liabilities) net",
        "label": "Gains (Losses) Recognised In Other Comprehensive Income Including Exchange Differences, Fair Value Measurement, Assets (Liabilities)",
        "documentation": "The gains (losses) recognised in other comprehensive income on the fair value measurement of assets and liabilities. [Refer: At fair value [member]; Other comprehensive income]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_GainsLossesRecognisedInProfitOrLossAttributableToChangeInUnrealisedGainsOrLossesForAssetsHeldAtEndOfPeriodFairValueMeasurement": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainsLossesRecognisedInProfitOrLossAttributableToChangeInUnrealisedGainsOrLossesForAssetsHeldAtEndOfPeriodFairValueMeasurement",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total",
        "label": "Gains (losses) recognised in profit or loss attributable to change in unrealised gains or losses for assets held at end of period, fair value measurement"
       }
      },
      "en": {
       "role": {
        "documentation": "The gains (losses) recognised in profit or loss for assets measured at fair value that are attributable to the change in unrealised gains or losses relating to those assets held at the end of the reporting period. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r171"
     ]
    },
    "ifrs-full_GainsLossesRecognisedInProfitOrLossFairValueMeasurementAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainsLossesRecognisedInProfitOrLossFairValueMeasurementAssets",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total gains and losses in the period recognised in the income statement, assets",
        "label": "Gains (losses) recognised in profit or loss including exchange differences, fair value measurement, assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The gains (losses) including exchange differences recognised in profit or loss on the fair value measurement of assets. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r166",
      "r532"
     ]
    },
    "bbplc_GainsLossesRecognisedInProfitOrLossFairValueMeasurementAssetsLiabilitiesNet": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "GainsLossesRecognisedInProfitOrLossFairValueMeasurementAssetsLiabilitiesNet",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Gains (losses) recognised in profit or loss, fair value measurement, assets (liabilities) net",
        "label": "Gains (Losses) Recognised In Profit Or Loss, Fair Value Measurement, Assets (Liabilities) Net",
        "documentation": "The gains (losses) recognised in profit or loss on the fair value measurement of assets and liabilities. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_GainsLossesRecognisedInProfitOrLossFairValueMeasurementLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GainsLossesRecognisedInProfitOrLossFairValueMeasurementLiabilities",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total gains and losses in the period recognised in the income statement, liabilities",
        "label": "Gains (losses) recognised in profit or loss including exchange differences, fair value measurement, liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The gains (losses) including exchange differences recognised in profit or loss on the fair value measurement of liabilities. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r166",
      "r532"
     ]
    },
    "bbplc_GeneralMotorsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "GeneralMotorsMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "General Motors",
        "label": "General Motors [Member]",
        "documentation": "General Motors"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_GeographicalAreasAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GeographicalAreasAxis",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails",
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails",
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Geographical areas [axis]",
        "label": "Geographical areas [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r345",
      "r610",
      "r653",
      "r656",
      "r698"
     ]
    },
    "ifrs-full_GeographicalAreasDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GeographicalAreasDomain",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails",
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails",
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Geographical areas [domain]",
        "label": "Geographical areas [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for aggregated geographical areas. It also represents the standard value for the 'Geographical areas' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r345",
      "r610",
      "r653",
      "r656",
      "r698"
     ]
    },
    "bbplc_GermanConsumerFinancePortfolioMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "GermanConsumerFinancePortfolioMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "German Consumer Finance portfolio",
        "label": "German Consumer Finance Portfolio [Member]",
        "documentation": "German Consumer Finance Portfolio"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_Goodwill": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "Goodwill",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails": {
       "parentTag": "ifrs-full_IntangibleAssetsAndGoodwill",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofgoodwillallocatedtobusinessoperationsaccordingtobusinesssegmentsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Goodwill",
        "label": "Goodwill"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of assets representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognised. [Refer: Total for all business combinations [member]]"
       }
      }
     },
     "auth_ref": [
      "r80",
      "r87",
      "r230",
      "r435",
      "r440",
      "r473",
      "r566"
     ]
    },
    "ifrs-full_GoodwillMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GoodwillMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Goodwill",
        "label": "Goodwill [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for goodwill. [Refer: Goodwill]"
       }
      }
     },
     "auth_ref": [
      "r621",
      "r705"
     ]
    },
    "bbplc_GovernmentAndCentralBankMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "GovernmentAndCentralBankMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Government and central bank",
        "label": "Government And Central Bank [Member]",
        "documentation": "This member stands for the government and central bank industry."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_GovernmentAndGovernmentSponsoredDebtMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "GovernmentAndGovernmentSponsoredDebtMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Government and Government sponsored debt",
        "label": "Government And Government Sponsored Debt [Member]",
        "documentation": "Government And Government Sponsored Debt"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_GreaterThan30DaysPastDueMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "GreaterThan30DaysPastDueMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Greater than 30 days past due",
        "label": "Greater Than 30 Days Past Due [Member]",
        "documentation": "This member stands for a time band of later than one month."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_GrossCarryingAmountMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GrossCarryingAmountMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Gross exposure",
        "netLabel": "Carrying amount",
        "verboseLabel": "Cost",
        "label": "Gross carrying amount [member]"
       }
      }
     },
     "auth_ref": [
      "r14",
      "r101",
      "r113",
      "r116",
      "r230",
      "r286",
      "r296",
      "r400",
      "r450",
      "r455",
      "r458",
      "r513",
      "r517",
      "r669"
     ]
    },
    "bbplc_GrossDomesticProductEconomicVariableMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "GrossDomesticProductEconomicVariableMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "GDP",
        "label": "Gross Domestic Product, Economic Variable [Member]",
        "documentation": "This member stands for Gross Domestic Product, a key historic macroeconomic core variable. The GDP is compared against the forecast paths of the probability weights for each scenario, demonstrating the highest annual growth in the Upside scenarios; 5 year average in Baseline; lowest annual growth in Downside scenarios."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_GrossFinancialAssetsSetOffAgainstFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GrossFinancialAssetsSetOffAgainstFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Amounts offset",
        "label": "Gross financial assets set off against financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial assets set off against financial liabilities when an entity: (a) currently has a legally enforceable right to set off the recognised amounts; and (b) intends either to settle on a net basis, or to realise the asset and settle the liability simultaneously. [Refer: Financial assets; Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r240",
      "r484"
     ]
    },
    "ifrs-full_GrossFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GrossFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Gross amounts",
        "label": "Gross financial assets subject to offsetting, enforceable master netting arrangements or similar agreements"
       }
      },
      "en": {
       "role": {
        "documentation": "The gross amount of recognised financial assets that are subject either to offsetting or to an enforceable master netting arrangement or similar agreement. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r239"
     ]
    },
    "ifrs-full_GrossFinancialLiabilitiesSetOffAgainstFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GrossFinancialLiabilitiesSetOffAgainstFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Amounts offset",
        "label": "Gross financial liabilities set off against financial assets subject to offsetting, enforceable master netting arrangements or similar agreements"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial liabilities set off against financial assets when an entity: (a) currently has a legally enforceable right to set off the recognised amounts; and (b) intends either to settle on a net basis or to realise the asset and settle the liability simultaneously. [Refer: Financial assets; Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r240",
      "r484"
     ]
    },
    "ifrs-full_GrossFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GrossFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Gross amounts",
        "label": "Gross financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements"
       }
      },
      "en": {
       "role": {
        "documentation": "The gross amount of recognised financial liabilities that are subject either to offsetting or to an enforceable master netting arrangement or similar agreement. [Refer: Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r239"
     ]
    },
    "ifrs-full_GrossLeaseLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "GrossLeaseLiabilities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofmaturityanalysisofleaseliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total undiscounted lease liabilities",
        "label": "Gross lease liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of contractual undiscounted cash flows in relation to lease liabilities before deducting finance charges. [Refer: Lease liabilities]"
       }
      }
     },
     "auth_ref": [
      "r194",
      "r367",
      "r675"
     ]
    },
    "bbplc_GrowthRateMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "GrowthRateMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Terminal growth rate",
        "label": "Growth Rate, Measurement Input [Member]",
        "documentation": "Growth Rate, Measurement Input"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_GuaranteesAndLettersOfCreditPledgedAsCollateralSecurityMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "GuaranteesAndLettersOfCreditPledgedAsCollateralSecurityMember",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Guarantees and letters of credit pledged as collateral security",
        "label": "Guarantees And Letters Of Credit Pledged As Collateral Security [Member]",
        "documentation": "This member stands for guarantees and letters of credit pledged as collateral security."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_HMRevenueAndCustomsHMRCAssessmentsConcerningUKValueAddedTaxMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "HMRevenueAndCustomsHMRCAssessmentsConcerningUKValueAddedTaxMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "HMRC assessments concerning UK VAT",
        "label": "HM Revenue And Customs (HMRC) Assessments Concerning UK Value Added Tax [Member]",
        "documentation": "In March 2018 HMRC issued notices that have the effect of removing certain overseas subsidiaries that have operations in the UK from Barclays UK VAT group, in which group supplies between members are generally free from VAT."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_HedgeFundInvestmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "HedgeFundInvestmentsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Hedge funds",
        "label": "Hedge fund investments [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for investments in hedge funds."
       }
      }
     },
     "auth_ref": [
      "r640",
      "r650"
     ]
    },
    "bbplc_HedgeFundsAmountContributedToFairValueOfPlanAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "HedgeFundsAmountContributedToFairValueOfPlanAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails": {
       "parentTag": "ifrs-full_PlanAssetsAtFairValue",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Hedge funds",
        "label": "Hedge Funds, Amount Contributed To Fair Value Of Plan Assets",
        "documentation": "Hedge Funds, Amount Contributed To Fair Value Of Plan Assets"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_HedgedAssetsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "HedgedAssetsMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Hedged assets",
        "label": "Hedged Assets [Member]",
        "documentation": "The hedged item, recognised as an asset."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_HedgedItemAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "HedgedItemAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails": {
       "parentTag": "bbplc_HedgedItemsNet",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Carrying amount, hedged assets",
        "label": "Hedged item, assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of a hedged item, recognised as an asset. [Refer: Hedged items [domain]]"
       }
      }
     },
     "auth_ref": [
      "r260",
      "r495"
     ]
    },
    "ifrs-full_HedgedItemLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "HedgedItemLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails": {
       "parentTag": "bbplc_HedgedItemsNet",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Carrying amount, hedged liabilities",
        "label": "Hedged item, liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of a hedged item, recognised as a liability. [Refer: Hedged items [domain]]"
       }
      }
     },
     "auth_ref": [
      "r260",
      "r495"
     ]
    },
    "ifrs-full_HedgedItemsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "HedgedItemsAxis",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Hedged items [axis]",
        "label": "Hedged items [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r267",
      "r499"
     ]
    },
    "ifrs-full_HedgedItemsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "HedgedItemsDomain",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Hedged items [domain]",
        "label": "Hedged items [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for hedged items. A hedged item can be a recognised asset or liability, an unrecognised firm commitment, a forecast transaction or a net investment in a foreign operation. The hedged item can be: (a) a single item; or (b) a group of items (subject to paragraphs 6.6.1\u20136.6.6 and B6.6.1\u2013B6.6.16 of IFRS 9). A hedged item can also be a component of such an item or group of items (see paragraphs 6.3.7 and B6.3.7\u2013B6.3.25 of IFRS 9). This member also represents the standard value for the 'Hedged items' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r267",
      "r499"
     ]
    },
    "bbplc_HedgedItemsNet": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "HedgedItemsNet",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total hedged items",
        "label": "Hedged Items, Net",
        "documentation": "The amount of a hedged item, recognised as an assets less liabilities. [Refer: Hedged items [member]]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_HedgedLiabilitiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "HedgedLiabilitiesMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Hedged liabilities",
        "label": "Hedged Liabilities [Member]",
        "documentation": "The hedged item, recognised as a liability. [Refer: Hedged items [member]]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_HedgesOfNetInvestmentInForeignOperationsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "HedgesOfNetInvestmentInForeignOperationsMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Hedges of net investments",
        "terseLabel": "Hedge of net investment in foreign operations",
        "netLabel": "Net investment",
        "label": "Hedges of net investment in foreign operations [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for hedges of the entity's monetary items that are receivable from or payable to a foreign operation, for which settlement is neither planned nor likely to occur in the foreseeable future. A foreign operation is an entity that is a subsidiary, associate, joint venture or branch of a reporting entity, the activities of which are based or conducted in a country or currency other than those of the reporting entity."
       }
      }
     },
     "auth_ref": [
      "r110",
      "r259",
      "r267",
      "r271",
      "r494",
      "r499",
      "r503"
     ]
    },
    "ifrs-full_HedgingInstrumentAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "HedgingInstrumentAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Hedging instrument, assets",
        "label": "Hedging instrument, assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of a hedging instrument, recognised as an asset. [Refer: Hedging instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r256",
      "r491"
     ]
    },
    "ifrs-full_HedgingInstrumentLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "HedgingInstrumentLiabilities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Hedging instrument, liabilities",
        "label": "Hedging instrument, liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of a hedging instrument, recognised as a liability. [Refer: Hedging instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r256",
      "r491"
     ]
    },
    "ifrs-full_HedgingInstrumentsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "HedgingInstrumentsAxis",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Hedging instruments [axis]",
        "label": "Hedging instruments [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r253",
      "r259",
      "r494"
     ]
    },
    "ifrs-full_HedgingInstrumentsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "HedgingInstrumentsDomain",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Hedging instruments [domain]",
        "label": "Hedging instruments [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for hedging instruments. A hedging instrument can be a designated: (a) derivative measured at fair value through profit or loss, except for some written options (see paragraph B6.2.4 of IFRS 9); (b) non-derivative financial asset or non-derivative financial liability measured at fair value through profit or loss, unless it is a financial liability designated as at fair value through profit or loss for which the amount of its change in fair value that is attributable to changes in the credit risk of that liability is presented in other comprehensive income in accordance with paragraph 5.7.7 of IFRS 9. For a hedge of foreign currency risk, the foreign currency risk component of a non-derivative financial asset or a non-derivative financial liability may be designated as a hedging instrument provided that it is not an investment in an equity instrument for which an entity has elected to present changes in fair value in other comprehensive income in accordance with paragraph 5.7.5 of IFRS 9. This member also represents the standard value for the 'Hedging instruments' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r253",
      "r259",
      "r494"
     ]
    },
    "bbplc_HeldForRiskManagementMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "HeldForRiskManagementMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Held for risk management",
        "label": "Held For Risk Management [Member]",
        "documentation": "This member stands for derivatives held for risk management by th entity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_HeldForTradingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "HeldForTradingMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Held for trading",
        "label": "Held For Trading [Member]",
        "documentation": "This member stands for financial instruments categorized as held for trading."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_HigherRiskBMinusAndBelowMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "HigherRiskBMinusAndBelowMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Higher Risk",
        "label": "Higher Risk (B Minus And below) [Member]",
        "documentation": "This member stands for the Higher risk internal credit grade. There is concern over the obligors ability to make payments when due. However, these have not yet converted to actual delinquency. There may also be doubts over the value of collateral or security provided. However, the borrower or counterparty is continuing to make payments when due and is expected to settle all outstanding amounts of principal and interest."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_HighestPaidDirectorMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "HighestPaidDirectorMember",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Highest paid director",
        "label": "Highest Paid Director [Member]",
        "documentation": "This member stands for the highest paid director."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_HistoricalVolatilityForSharesMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "HistoricalVolatilityForSharesMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Equity volatility",
        "label": "Historical volatility for shares, measurement input [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the historical volatility for shares used as a measurement input."
       }
      }
     },
     "auth_ref": [
      "r644"
     ]
    },
    "bbplc_HoldingPeriodMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "HoldingPeriodMember",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Holding period",
        "label": "Holding Period [Member]",
        "documentation": "Holding Period"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_HomeLoansMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "HomeLoansMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Home Loans",
        "label": "Home Loans [Member]",
        "documentation": "Home Loans"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_HousePriceIndexEconomicCoreVariableMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "HousePriceIndexEconomicCoreVariableMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "HPI",
        "label": "House Price Index, Economic Core Variable [Member]",
        "documentation": "This member stands for the House Price Index, a key historic macroeconomic core variable. The House Price Index is compared against the forecast paths of the probability weights for each scenario, demonstrating 5 year cumulative growth in Upside scenarios; 5 year average in Baseline; cumulative fall (peak-to-trough) in Downside scenarios."
       }
      }
     },
     "auth_ref": []
    },
    "currency_INR": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/currency/2025",
     "localname": "INR",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "INR",
        "label": "India, Rupees"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IPathBloombergCommodityIndexTotalReturnSMETNMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IPathBloombergCommodityIndexTotalReturnSMETNMember",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "iPath\u00ae\u00a0Bloomberg Commodity Index Total ReturnSM\u00a0ETN",
        "label": "iPath\u00ae\u00a0Bloomberg Commodity Index Total ReturnSM\u00a0ETN [Member]",
        "documentation": "iPath\u00ae\u00a0Bloomberg Commodity Index Total ReturnSM\u00a0ETN"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IPathSelectMLPETNMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IPathSelectMLPETNMember",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "iPath\u00ae Select MLP ETN",
        "label": "iPath\u00ae Select MLP ETN [Member]",
        "documentation": "iPath\u00ae Select MLP ETN"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IPathSeriesBCarbonETNMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IPathSeriesBCarbonETNMember",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "iPath\u00ae\u00a0Series B Carbon ETN",
        "label": "iPath\u00ae\u00a0Series B Carbon ETN [Member]",
        "documentation": "iPath\u00ae\u00a0Series B Carbon ETN"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IPathSeriesBSP500VIXMidTermFuturesTMETNsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IPathSeriesBSP500VIXMidTermFuturesTMETNsMember",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "iPath\u00ae\u00a0Series B S&amp;P 500 VIX\u00a0Mid-Term\u00a0FuturesTM\u00a0ETNs",
        "label": "iPath\u00ae\u00a0Series B S&amp;P 500 VIX\u00a0Mid-Term\u00a0FuturesTM\u00a0ETNs [Member]",
        "documentation": "iPath\u00ae\u00a0Series B S&amp;P 500 VIX\u00a0Mid-Term\u00a0FuturesTM\u00a0ETNs"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IPathSeriesBSP500VIXShortTermFuturesTMETNsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IPathSeriesBSP500VIXShortTermFuturesTMETNsMember",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "iPath\u00ae\u00a0Series B S&amp;P 500 VIX Short-Term FuturesTM\u00a0ETNs",
        "label": "iPath\u00ae\u00a0Series B S&amp;P 500 VIX Short-Term FuturesTM\u00a0ETNs [Member]",
        "documentation": "iPath\u00ae\u00a0Series B S&amp;P 500 VIX Short-Term FuturesTM\u00a0ETNs"
       }
      }
     },
     "auth_ref": []
    },
    "country_IT": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/country/2025",
     "localname": "IT",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Italy",
        "label": "ITALY"
       }
      }
     },
     "auth_ref": []
    },
    "dei_IcfrAuditorAttestationFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "IcfrAuditorAttestationFlag",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "ICFR Auditor Attestation Flag",
        "label": "ICFR Auditor Attestation Flag"
       }
      }
     },
     "auth_ref": [
      "r726",
      "r727",
      "r750"
     ]
    },
    "bbplc_ImpairmentAllowanceCoverageRatio": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ImpairmentAllowanceCoverageRatio",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Coverage ratio",
        "label": "Impairment Allowance Coverage Ratio",
        "documentation": "The impairment allowances as a percentage of Credit Risk Loan balances. The impairment allowance is the aggregate of the identified and unidentified impairment (UI) balances."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ImpairmentAllowanceIncludingLoanCommitmentsAndFinancialGuaranteeContractsPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ImpairmentAllowanceIncludingLoanCommitmentsAndFinancialGuaranteeContractsPercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Proportion of Management adjustments to total impairment allowance",
        "label": "Impairment Allowance Including Loan Commitments And Financial Guarantee Contracts, Percentage",
        "documentation": "The amount total impairment allowance, including off-balance sheet loan commitments and financial guarantee contracts, expressed as a percentage."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ImpairmentAllowanceTotalMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ImpairmentAllowanceTotalMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total impairment allowance",
        "label": "Impairment Allowance, Total [Member]",
        "documentation": "Impairment Allowance, Total"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ImpairmentLossAssetsRecognisedFromCostsIncurredToObtainOrFulfilContractsWithCustomers": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ImpairmentLossAssetsRecognisedFromCostsIncurredToObtainOrFulfilContractsWithCustomers",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Impairment loss, assets recognised from costs incurred to obtain or fulfil contracts with customers",
        "label": "Impairment loss, assets recognised from costs incurred to obtain or fulfil contracts with customers"
       }
      }
     },
     "auth_ref": [
      "r186",
      "r362"
     ]
    },
    "ifrs-full_ImpairmentLossOnReceivablesOrContractAssetsArisingFromContractsWithCustomers": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ImpairmentLossOnReceivablesOrContractAssetsArisingFromContractsWithCustomers",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Impairment loss, capitalised contract costs",
        "label": "Impairment loss on receivables or contract assets arising from contracts with customers"
       }
      }
     },
     "auth_ref": [
      "r180",
      "r359"
     ]
    },
    "ifrs-full_ImpairmentLossRecognisedInProfitOrLoss": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ImpairmentLossRecognisedInProfitOrLoss",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails": {
       "parentTag": "ifrs-full_ImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Impairment charges /(releases)",
        "label": "Impairment loss recognised in profit or loss"
       }
      }
     },
     "auth_ref": [
      "r70",
      "r73",
      "r432"
     ]
    },
    "ifrs-full_ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsAndGoodwill": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsAndGoodwill",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Impairment charge",
        "label": "Impairment loss recognised in profit or loss, intangible assets and goodwill"
       }
      }
     },
     "auth_ref": [
      "r856"
     ]
    },
    "bbplc_ImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipmentAndIntangibleAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipmentAndIntangibleAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails": {
       "parentTag": "bbplc_InfrastructureCosts",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Impairment of property, equipment and intangible assets",
        "label": "Impairment Loss Recognised in Profit Or Loss, Property Plant And Equipment And Intangible Assets",
        "documentation": "Impairment Loss Recognised in Profit Or Loss, Property Plant And Equipment And Intangible Assets"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipmentIncludingRightofuseAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ImpairmentLossRecognisedInProfitOrLossPropertyPlantAndEquipmentIncludingRightofuseAssets",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Impairment charge",
        "label": "Impairment loss recognised in profit or loss, property, plant and equipment including right-of-use assets"
       }
      }
     },
     "auth_ref": [
      "r840"
     ]
    },
    "ifrs-full_ImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_ProfitLossBeforeTax",
       "weight": -1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Credit impairment charges",
        "terseLabel": "Total credit impairment charge for the year",
        "negatedLabel": "Credit impairment (charges)/releases",
        "totalLabel": "Total credit impairment charges /(releases)",
        "label": "Impairment loss (reversal of impairment loss) recognised in profit or loss"
       }
      }
     },
     "auth_ref": [
      "r376",
      "r605"
     ]
    },
    "ifrs-full_ImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLossLoansAndAdvances": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLossLoansAndAdvances",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net write-offs",
        "label": "Impairment loss (reversal of impairment loss) recognised in profit or loss, loans and advances"
       }
      }
     },
     "auth_ref": [
      "r887"
     ]
    },
    "bbplc_ImpairmentRecognisedInInvestmentsInSubsidiaries": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ImpairmentRecognisedInInvestmentsInSubsidiaries",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement": {
       "parentTag": "bbplc_ProfitLossFromOperatingActivitiesBeforeImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
       "weight": -1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 20.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Impairment of Investments in subsidiaries",
        "negatedTerseLabel": "Impairment of investments in subsidiaries",
        "label": "Impairment Recognised In Investments In Subsidiaries",
        "documentation": "Impairment Recognised In Investments In Subsidiaries"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ImpairmentReviewValueInUseForecastPeriod": {
     "xbrltype": "durationItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ImpairmentReviewValueInUseForecastPeriod",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "VIU forecast period",
        "label": "Impairment Review, Value In Use, Forecast Period",
        "documentation": "Impairment Review, Value In Use, Forecast Period"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IncomeFromIndividualCountriesWhichRepresentMoreThan5OfTotalIncomeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncomeFromIndividualCountriesWhichRepresentMoreThan5OfTotalIncomeMember",
     "presentation": [
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Income from individual countries which represent more than 5% of total income",
        "label": "Income From Individual Countries Which Represent More Than 5% Of Total Income [Member]",
        "documentation": "This member stands for individual country locations individually representing more than five percent of total income."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncomeStatementAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncomeStatementAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Profit or loss [abstract]",
        "label": "Profit or loss [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncomeTaxExpenseContinuingOperations": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncomeTaxExpenseContinuingOperations",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_ProfitLoss",
       "weight": -1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      },
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/TaxDisclosureofcomponentsofincometaxDetails",
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Taxation",
        "totalLabel": "Tax charge",
        "label": "Tax expense (income)"
       }
      }
     },
     "auth_ref": [
      "r1",
      "r4",
      "r5",
      "r62",
      "r152",
      "r334",
      "r390",
      "r392",
      "r393",
      "r596"
     ]
    },
    "ifrs-full_IncomeTaxRelatingToCashFlowHedgesOfOtherComprehensiveIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncomeTaxRelatingToCashFlowHedgesOfOtherComprehensiveIncome",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 9.0
      },
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 10.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectonthereservesasaresultofhedgeaccountingDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Tax",
        "label": "Income tax relating to cash flow hedges included in other comprehensive income"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of income tax relating to amounts recognised in other comprehensive income in relation to cash flow hedges. [Refer: Cash flow hedges [member]; Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r3",
      "r597"
     ]
    },
    "bbplc_IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeDeferredTaxAssetLiability": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeDeferredTaxAssetLiability",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other comprehensive income and reserves",
        "label": "Income Tax Relating To Components Of Other Comprehensive Income, Deferred Tax Asset (Liability)",
        "documentation": "The amount of deferred iasset (liabiltity) relating to amounts recognised in other comprehensive income and reserves. [Refer: Other comprehensive income]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLoss": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLoss",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Tax",
        "label": "Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of income tax relating to amounts recognised in other comprehensive income that will not be reclassified to profit or loss. [Refer: Income tax relating to components of other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r600"
     ]
    },
    "ifrs-full_IncomeTaxRelatingToExchangeDifferencesOnTranslationOfOtherComprehensiveIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncomeTaxRelatingToExchangeDifferencesOnTranslationOfOtherComprehensiveIncome",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectonthereservesasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Tax",
        "label": "Income tax relating to exchange differences on translation of foreign operations included in other comprehensive income"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of income tax relating to amounts recognised in other comprehensive income in relation to exchange differences on the translation of financial statements of foreign operations. [Refer: Other comprehensive income; Reserve of exchange differences on translation]"
       }
      }
     },
     "auth_ref": [
      "r3",
      "r597"
     ]
    },
    "ifrs-full_IncomeTaxRelatingToFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncomeTaxRelatingToFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 6.0
      },
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 7.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Tax",
        "label": "Income tax relating to financial assets measured at fair value through other comprehensive income included in other comprehensive income"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of income tax relating to amounts recognised in other comprehensive income in relation to financial assets measured at fair value through other comprehensive income applying paragraph 4.1.2A of IFRS 9. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r3",
      "r597"
     ]
    },
    "ifrs-full_IncomeTaxesPaidRefundClassifiedAsOperatingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncomeTaxesPaidRefundClassifiedAsOperatingActivities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": -1.0,
       "order": 18.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedNetLabel": "Corporate income tax paid",
        "negatedTerseLabel": "Corporate income tax",
        "label": "Income taxes paid (refund), classified as operating activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash flows from income taxes paid or refunded, classified as operating activities. [Refer: Income taxes paid (refund)]"
       }
      }
     },
     "auth_ref": [
      "r122",
      "r627"
     ]
    },
    "ifrs-full_IncreaseDecreaseInCashAndCashEquivalents": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseInCashAndCashEquivalents",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Net increase/(decrease) in cash and cash equivalents",
        "label": "Increase (decrease) in cash and cash equivalents after effect of exchange rate changes"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in cash and cash equivalents after the effect of exchange rate changes on cash and cash equivalents held in foreign currencies. [Refer: Cash and cash equivalents; Effect of exchange rate changes on cash and cash equivalents]"
       }
      }
     },
     "auth_ref": [
      "r128",
      "r387"
     ]
    },
    "ifrs-full_IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleDecreaseInActuarialAssumption": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleDecreaseInActuarialAssumption",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "(Decrease)/Increase in defined benefit obligation",
        "label": "Increase (decrease) in defined benefit obligation due to reasonably possible decrease in actuarial assumption"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in a defined benefit obligation that would have been caused by a decrease in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [domain]]"
       }
      }
     },
     "auth_ref": [
      "r34"
     ]
    },
    "ifrs-full_IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleIncreaseInActuarialAssumption": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseInDefinedBenefitObligationDueToReasonablyPossibleIncreaseInActuarialAssumption",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "(Decrease)/Increase in defined benefit obligation",
        "label": "Increase (decrease) in defined benefit obligation due to reasonably possible increase in actuarial assumption"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in a defined benefit obligation that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [domain]]"
       }
      }
     },
     "auth_ref": [
      "r34"
     ]
    },
    "bbplc_IncreaseDecreaseInDerivativeFairValueAdjustments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseInDerivativeFairValueAdjustments",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Increase (decrease) in derivative value due to adjustments",
        "label": "Increase (Decrease) In Derivative Fair Value Adjustments",
        "documentation": "The increase (decrease) in fair value adjustments of derivatives during the period."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IncreaseDecreaseInDrawdownsRepaymentsRiskParameterChangesAndOtherMovementsExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseInDrawdownsRepaymentsRiskParameterChangesAndOtherMovementsExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Net drawdowns, repayments, net re-measurement and movement due to exposure and risk parameter changes",
        "label": "Increase (Decrease) In Drawdowns, Repayments, Risk Parameter Changes And Other Movements, Exposure To Credit Risk On Loan Commitments And Financial Guarantee Contracts",
        "documentation": "The increase (decrease) in financial assets resulting from drawdowns, repayments, changes in models or risk parameters, and other movements, including the effect of moving between Stages 2 and 3 on expected credit losses."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncreaseDecreaseInEquityDueToReasonablyPossibleDecreaseInRiskExposureThatArisesFromContractsWithinScopeOfIFRS17": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseInEquityDueToReasonablyPossibleDecreaseInRiskExposureThatArisesFromContractsWithinScopeOfIFRS17",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Increase (decrease) in equity for the year due to reasonable possible decrease",
        "label": "Increase (decrease) in equity due to reasonably possible decrease in risk variable that arises from contracts within scope of IFRS 17"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in equity that would have been caused by a reasonably possible decrease in the risk variable that arises from contracts within the scope of IFRS 17."
       }
      }
     },
     "auth_ref": [
      "r206",
      "r207"
     ]
    },
    "bbplc_IncreaseDecreaseInEquityDueToReasonablyPossibleDecreaseInRiskVariableAsAPercentageOfTotalEquity": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseInEquityDueToReasonablyPossibleDecreaseInRiskVariableAsAPercentageOfTotalEquity",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Increase (decrease) in equity for the year due to reasonable possible decrease, percentage",
        "label": "Increase (Decrease) In Equity Due To Reasonably Possible Decrease In Risk Variable As A Percentage Of Total Equity",
        "documentation": "Increase (Decrease) In Equity Due To Reasonably Possible Decrease In Risk Variable As A Percentage Of Total Equity"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncreaseDecreaseInEquityDueToReasonablyPossibleIncreaseInRiskExposureThatArisesFromContractsWithinScopeOfIFRS17": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseInEquityDueToReasonablyPossibleIncreaseInRiskExposureThatArisesFromContractsWithinScopeOfIFRS17",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Increase (decrease) in equity for the year due to reasonable possible increase",
        "label": "Increase (decrease) in equity due to reasonably possible increase in risk variable that arises from contracts within scope of IFRS 17"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in equity that would have been caused by a reasonably possible increase in the risk variable that arises from contracts within the scope of IFRS 17."
       }
      }
     },
     "auth_ref": [
      "r206",
      "r207"
     ]
    },
    "bbplc_IncreaseDecreaseInEquityDueToReasonablyPossibleIncreaseInRiskVariableAsAPercentageOfTotalEquity": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseInEquityDueToReasonablyPossibleIncreaseInRiskVariableAsAPercentageOfTotalEquity",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Increase (decrease) in equity for the year due to reasonable possible increase, percentage",
        "label": "Increase (Decrease) In Equity Due To Reasonably Possible Increase In Risk Variable As A Percentage Of Total Equity",
        "documentation": "Increase (Decrease) In Equity Due To Reasonably Possible Increase In Risk Variable As A Percentage Of Total Equity"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncreaseDecreaseInExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContractsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseInExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContractsAbstract",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loan commitments and financial guarantee contracts",
        "label": "Increase (decrease) in exposure to credit risk on loan commitments and financial guarantee contracts [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncreaseDecreaseInFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseInFinancialAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "ECL movement",
        "label": "Increase (decrease) in financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in financial assets. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r285",
      "r286",
      "r511",
      "r513"
     ]
    },
    "ifrs-full_IncreaseDecreaseInFinancialAssetsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseInFinancialAssetsAbstract",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans and advances at amortised cost",
        "label": "Increase (decrease) in financial assets [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IncreaseDecreaseInFinancialInstrumentsWhichHedgeNetInvestmentsHedges": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseInFinancialInstrumentsWhichHedgeNetInvestmentsHedges",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Decrease in financial instruments which hedge net investments",
        "label": "Increase (Decrease) In Financial Instruments Which Hedge Net Investments, Hedges",
        "documentation": "The increase (decrease) in financial instruments which hedge net investments."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IncreaseDecreaseInForeignCurrencyNetInvestmentsHedgedItem": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseInForeignCurrencyNetInvestmentsHedgedItem",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Increase (decrease) in foreign currency net investments",
        "label": "Increase (Decrease) In Foreign Currency Net Investments, Hedged Item",
        "documentation": "The increase (decrease) in foreign currency net investments, hedged item."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IncreaseDecreaseInInputsAssumptionsAndEstimationTechniquesUsedToDetermineExpectedCreditLossesProbability": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseInInputsAssumptionsAndEstimationTechniquesUsedToDetermineExpectedCreditLossesProbability",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Changes in inputs, assumptions and estimation techniques used for ECL, probability",
        "label": "Increase (Decrease) In Inputs, Assumptions And Estimation Techniques Used To Determine Expected Credit Losses, Probability",
        "documentation": "Increase (Decrease) In Inputs, Assumptions And Estimation Techniques Used To Determine Expected Credit Losses, Probability"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncreaseDecreaseInNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseInNetDefinedBenefitLiabilityAsset",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofincomestatementchargeDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofincomestatementchargeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total",
        "label": "Increase (decrease) in net defined benefit liability (asset)"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in the net defined benefit liability (asset). [Refer: Net defined benefit liability (asset)]"
       }
      }
     },
     "auth_ref": [
      "r32",
      "r412"
     ]
    },
    "bbplc_IncreaseDecreaseInNetDefinedBenefitLiabilityAssetResultingFromTransferToASeparatePensionPlan": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseInNetDefinedBenefitLiabilityAssetResultingFromTransferToASeparatePensionPlan",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Increase (decrease) in net defined benefit liability (asset) resulting from transfer to a separate pension plan",
        "label": "Increase (Decrease) In Net Defined Benefit Liability Asset Resulting From Transfer To A Separate Pension Plan",
        "documentation": "Increase (Decrease) In Net Defined Benefit Liability Asset Resulting From Transfer To A Separate Pension Plan"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IncreaseDecreaseInNetDefinedBenefitLiabilityAssetsResultingFromCurtailmentsOrSettlements": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseInNetDefinedBenefitLiabilityAssetsResultingFromCurtailmentsOrSettlements",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofincomestatementchargeDetails": {
       "parentTag": "ifrs-full_IncreaseDecreaseInNetDefinedBenefitLiabilityAsset",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofincomestatementchargeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Curtailments or Settlements",
        "negatedTerseLabel": "Curtailments or settlements",
        "label": "Increase (Decrease) In Net Defined Benefit Liability (Assets) Resulting From Curtailments Or Settlements",
        "documentation": "Increase (Decrease) In Net Defined Benefit Liability (Assets) Resulting From Curtailments Or Settlements"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncreaseDecreaseInProfitLossDueToReasonablyPossibleDecreaseInRiskExposureThatArisesFromContractsWithinScopeOfIFRS17": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseInProfitLossDueToReasonablyPossibleDecreaseInRiskExposureThatArisesFromContractsWithinScopeOfIFRS17",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Increase (decrease) in profit for the year due to reasonably possible decrease",
        "label": "Increase (decrease) in profit (loss) due to reasonably possible decrease in risk variable that arises from contracts within scope of IFRS 17"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in profit (loss) that would have been caused by a reasonably possible decrease in the risk variable that arises from contracts within the scope of IFRS 17."
       }
      }
     },
     "auth_ref": [
      "r206",
      "r207"
     ]
    },
    "bbplc_IncreaseDecreaseInProfitLossDueToReasonablyPossibleDecreaseInRiskVariableAsAPercentageOfNetProfitAfterTax": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseInProfitLossDueToReasonablyPossibleDecreaseInRiskVariableAsAPercentageOfNetProfitAfterTax",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Increase (decrease) in profit for the year due to reasonable possibly decrease, percentage",
        "label": "Increase (Decrease) In Profit (Loss) Due To Reasonably Possible Decrease In Risk Variable As A Percentage Of Net Profit After Tax",
        "documentation": "Increase (Decrease) In Profit (Loss) Due To Reasonably Possible Decrease In Risk Variable As A Percentage Of Net Profit After Tax"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncreaseDecreaseInProfitLossDueToReasonablyPossibleIncreaseInRiskExposureThatArisesFromContractsWithinScopeOfIFRS17": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseInProfitLossDueToReasonablyPossibleIncreaseInRiskExposureThatArisesFromContractsWithinScopeOfIFRS17",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Increase (decrease) in profit for the year due to reasonable possibly increase",
        "label": "Increase (decrease) in profit (loss) due to reasonably possible increase in risk variable that arises from contracts within scope of IFRS 17"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in profit (loss) that would have been caused by a reasonably possible increase in the risk variable that arises from contracts within the scope of IFRS 17."
       }
      }
     },
     "auth_ref": [
      "r206",
      "r207"
     ]
    },
    "bbplc_IncreaseDecreaseInProfitLossDueToReasonablyPossibleIncreaseInRiskVariableAsAPercentageOfNetProfitAfterTax": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseInProfitLossDueToReasonablyPossibleIncreaseInRiskVariableAsAPercentageOfNetProfitAfterTax",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Increase (decrease) in profit for the year due to reasonable possibly increase, percentage",
        "label": "Increase (Decrease) In Profit (Loss) Due To Reasonably Possible Increase In Risk Variable As A Percentage Of Net Profit After Tax",
        "documentation": "Increase (Decrease) In Profit (Loss) Due To Reasonably Possible Increase In Risk Variable As A Percentage Of Net Profit After Tax"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IncreaseDecreaseInStructuralCurrencyExposuresNetOfHedgingInstruments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseInStructuralCurrencyExposuresNetOfHedgingInstruments",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Decrease in structural currency exposures, net of hedging instruments",
        "label": "Increase (Decrease) In Structural Currency Exposures, Net Of Hedging Instruments",
        "documentation": "The increase (decrease) in structural currency exposures, net of hedging instruments during the period."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncreaseDecreaseThroughAmountsRecognisedInProfitOrLossAggregateDifferenceBetweenFairValueAtInitialRecognitionAndAmountDeterminedUsingValuationTechniqueYetToBeRecognised": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughAmountsRecognisedInProfitOrLossAggregateDifferenceBetweenFairValueAtInitialRecognitionAndAmountDeterminedUsingValuationTechniqueYetToBeRecognised",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Difference between initial FV and transaction price to be recognised in profit or loss, amortisation and releases",
        "label": "Increase (decrease) through amounts recognised in profit or loss, aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in the aggregate difference between the fair value at initial recognition and the transaction price of financial instruments yet to be recognised in profit or loss resulting from amounts recognised in profit or loss. [Refer: Aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss; Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r660",
      "r685",
      "r706"
     ]
    },
    "bbplc_IncreaseDecreaseThroughAssetsHeldForSaleMovementsFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseThroughAssetsHeldForSaleMovementsFinancialAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "ECL charge on assets held for sale",
        "label": "Increase (Decrease) Through Assets Held For Sale Movements, Financial Assets",
        "documentation": "Increase (Decrease) Through Assets Held For Sale Movements, Financial Assets"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncreaseDecreaseThroughChangesInForeignExchangeRatesNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughChangesInForeignExchangeRatesNetDefinedBenefitLiabilityAsset",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Exchange and other movements",
        "label": "Increase (decrease) in net defined benefit liability (asset) resulting from changes in foreign exchange rates, net defined benefit liability (asset)"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in the net defined benefit liability (asset) resulting from changes in foreign exchange rates. [Refer: Net defined benefit liability (asset)]"
       }
      }
     },
     "auth_ref": [
      "r29"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughChangesInModelsOrRiskParametersFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughChangesInModelsOrRiskParametersFinancialAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Refinements to models used for calculation",
        "label": "Increase (decrease) through changes in models or risk parameters, financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in financial assets resulting from changes in models or risk parameters. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r662",
      "r686",
      "r707"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughEffectOfChangesInForeignExchangeRatesLiabilitiesArisingFromFinancingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughEffectOfChangesInForeignExchangeRatesLiabilitiesArisingFromFinancingActivities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofleaseliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Exchange and other movements",
        "label": "Increase (decrease) through effect of changes in foreign exchange rates, liabilities arising from financing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in liabilities arising from financing activities resulting from the effect of changes in foreign exchange rates. [Refer: Liabilities arising from financing activities]"
       }
      }
     },
     "auth_ref": [
      "r126",
      "r385"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughExerciseOfOptions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughExerciseOfOptions",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Vesting of Barclays PLC shares under share-based payment schemes",
        "label": "Increase (decrease) through exercise of options, equity"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in equity resulting from the exercise of options."
       }
      }
     },
     "auth_ref": [
      "r879"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughForeignExchangeAndOtherMovementsFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughForeignExchangeAndOtherMovementsFinancialAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Total exchange and other adjustments",
        "label": "Increase (decrease) through foreign exchange and other movements, financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in financial assets resulting from foreign exchange and other movements. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r662",
      "r686",
      "r707"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughModificationOfContractualCashFlowsFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughModificationOfContractualCashFlowsFinancialAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net drawdowns, repayments, net re-measurement and movements due to exposure and risk parameter changes",
        "label": "Increase (decrease) through modification of contractual cash flows, financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in financial assets resulting from the modification of contractual cash flows. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r664",
      "r709"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughNetExchangeDifferencesDeferredTaxLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughNetExchangeDifferencesDeferredTaxLiabilityAsset",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Other movements",
        "label": "Increase (decrease) through net exchange differences, deferred tax liability (asset)"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in deferred tax liability (asset) resulting from the net exchange differences arising when the financial statements are translated from the functional currency into a different presentation currency, including the translation of a foreign operation into the presentation currency of the reporting entity. [Refer: Deferred tax liability (asset)]"
       }
      }
     },
     "auth_ref": [
      "r837"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughNetExchangeDifferencesIntangibleAssetsAndGoodwill": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughNetExchangeDifferencesIntangibleAssetsAndGoodwill",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Exchange and other movements",
        "label": "Increase (decrease) through net exchange differences, intangible assets and goodwill"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in intangible assets and goodwill resulting from the net exchange differences arising when the financial statements are translated from the functional currency into a different presentation currency, including the translation of a foreign operation into the presentation currency of the reporting entity. [Refer: Intangible assets and goodwill]"
       }
      }
     },
     "auth_ref": [
      "r857"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughNetExchangeDifferencesOtherProvisions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughNetExchangeDifferencesOtherProvisions",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Exchange and other movements",
        "label": "Increase (decrease) through net exchange differences, other provisions"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in other provisions resulting from foreign currency exchange rate changes on provisions measured in a currency different from the entity's presentation currency. [Refer: Other provisions]"
       }
      }
     },
     "auth_ref": [
      "r853"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughNetExchangeDifferencesPropertyPlantAndEquipmentIncludingRightofuseAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughNetExchangeDifferencesPropertyPlantAndEquipmentIncludingRightofuseAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Exchange and other movements",
        "label": "Increase (decrease) through net exchange differences, property, plant and equipment including right-of-use assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in property, plant and equipment including right-of-use assets resulting from net exchange differences arising on the translation of the financial statements from the functional currency into a different presentation currency, including the translation of a foreign operation into the presentation currency of the reporting entity. [Refer: Property, plant and equipment including right-of-use assets]"
       }
      }
     },
     "auth_ref": [
      "r840"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughNewTransactionsAggregateDifferenceBetweenFairValueAtInitialRecognitionAndAmountDeterminedUsingValuationTechniqueYetToBeRecognised": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughNewTransactionsAggregateDifferenceBetweenFairValueAtInitialRecognitionAndAmountDeterminedUsingValuationTechniqueYetToBeRecognised",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Difference between initial FV and transaction price to be recognised in profit or loss, additions",
        "label": "Increase (decrease) through new transactions, aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in the aggregate difference between the fair value at initial recognition and the transaction price of financial instruments yet to be recognised in profit or loss resulting from new transactions. [Refer: Aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss; Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r660",
      "r685",
      "r706"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughObtainingOrLosingControlOfSubsidiariesOrOtherBusinessesLiabilitiesArisingFromFinancingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughObtainingOrLosingControlOfSubsidiariesOrOtherBusinessesLiabilitiesArisingFromFinancingActivities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofleaseliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Disposals",
        "label": "Increase (decrease) through obtaining or losing control of subsidiaries or other businesses, liabilities arising from financing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in liabilities arising from financing activities resulting from obtaining or losing control of subsidiaries or other businesses. [Refer: Liabilities arising from financing activities; Total for all subsidiaries [member]]"
       }
      }
     },
     "auth_ref": [
      "r125",
      "r384"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughOtherChangesNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughOtherChangesNetDefinedBenefitLiabilityAsset",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofincomestatementchargeDetails": {
       "parentTag": "ifrs-full_IncreaseDecreaseInNetDefinedBenefitLiabilityAsset",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofincomestatementchargeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other movements",
        "label": "Increase (decrease) in net defined benefit liability (asset) resulting from other changes"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in the net defined benefit liability (asset) resulting from changes that the entity does not separately disclose in the same statement or note. [Refer: Net defined benefit liability (asset)]"
       }
      }
     },
     "auth_ref": [
      "r844"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughOtherContributionsByOwners": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughOtherContributionsByOwners",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net equity impact on inter Barclays PLC Group transfers",
        "label": "Increase through other contributions by owners, equity"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase in equity through other contributions by owners that the entity does not separately disclose in the same statement or note."
       }
      }
     },
     "auth_ref": [
      "r553"
     ]
    },
    "bbplc_IncreaseDecreaseThroughRecoveriesAndReimbursementsFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseDecreaseThroughRecoveriesAndReimbursementsFinancialAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Recoveries and reimbursements",
        "label": "Increase (Decrease) Through Recoveries And Reimbursements, Financial Assets",
        "documentation": "Increase (Decrease) Through Recoveries And Reimbursements, Financial Assets"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughSharebasedPaymentTransactions",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Employee settled Barclays PLC share schemes",
        "label": "Increase (decrease) through share-based payment transactions, equity"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in equity resulting from share-based payment transactions. [Refer: Equity]"
       }
      }
     },
     "auth_ref": [
      "r553"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughTransfersAndOtherChangesEquity": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other reserve movements",
        "label": "Increase (decrease) through other changes, equity"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in equity resulting from changes that the entity does not separately disclose in the same statement or note. [Refer: Equity]"
       }
      }
     },
     "auth_ref": [
      "r554"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughTransfersExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughTransfersExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net transfers between stages",
        "label": "Increase (decrease) through transfers, exposure to credit risk on loan commitments and financial guarantee contracts"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in exposure to credit risk on loan commitments and financial guarantee contracts resulting from transfers. [Refer: Exposure to credit risk on loan commitments and financial guarantee contracts]"
       }
      }
     },
     "auth_ref": [
      "r662",
      "r666",
      "r686",
      "r707",
      "r711"
     ]
    },
    "ifrs-full_IncreaseDecreaseThroughTransfersFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseDecreaseThroughTransfersFinancialAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Transfers",
        "label": "Increase (decrease) through transfers, financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase (decrease) in financial assets resulting from transfers. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r662",
      "r666",
      "r686",
      "r707",
      "r711"
     ]
    },
    "bbplc_IncreaseForExtensionOptionExpectedToBeExercisedGrossLeaseLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseForExtensionOptionExpectedToBeExercisedGrossLeaseLiabilities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/LeasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash flow increased for early extension option expected to be exercised",
        "label": "Increase For Extension Option Expected To Be Exercised, Gross Lease Liabilities",
        "documentation": "Increase For Extension Option Expected To Be Exercised, Gross Lease Liabilities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IncreaseInActuarialAssumptionDuration": {
     "xbrltype": "durationItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseInActuarialAssumptionDuration",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Increase in actuarial assumption, duration",
        "label": "Increase In Actuarial Assumption, Duration",
        "documentation": "Increase In Actuarial Assumption, Duration"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IncreaseInFairValueMeasurementDueToChangeInMultipleUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsRecognisedInOCIAfterTaxAssetsLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseInFairValueMeasurementDueToChangeInMultipleUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsRecognisedInOCIAfterTaxAssetsLiabilities",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Favourable changes, Equity",
        "label": "Increase In Fair Value Measurement Due To Change In Multiple Unobservable Inputs To Reflect Reasonably Possible Alternative Assumptions, Recognised In OCI, After Tax, Assets (Liabilities)",
        "documentation": "The amount of increase in the fair value measurement of assets (liabilities), recognised in other comprehensive income after tax, due to a change in multiple unobservable inputs to reflect reasonably possible alternative assumptions. [Refer: Tax income (expense)]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IncreaseInFairValueMeasurementDueToChangeInMultipleUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsRecognisedInProfitOrLossAfterTaxAssetsLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseInFairValueMeasurementDueToChangeInMultipleUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsRecognisedInProfitOrLossAfterTaxAssetsLiabilities",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Favorable changes, Income statement",
        "label": "Increase In Fair Value Measurement Due To Change In Multiple Unobservable Inputs To Reflect Reasonably Possible Alternative Assumptions, Recognised In Profit Or Loss, After Tax, Assets (Liabilities)",
        "documentation": "The amount of increase in the fair value measurement of assets (liabilities), recognised in profit or loss after tax, due to a change in multiple unobservable inputs to reflect reasonably possible alternative assumptions. [Refer: Tax income (expense)]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IncreaseInFairValueMeasurementDueToChangeInOneOrMoreUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsAssetsLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IncreaseInFairValueMeasurementDueToChangeInOneOrMoreUnobservableInputsToReflectReasonablyPossibleAlternativeAssumptionsAssetsLiabilities",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Favorable changes",
        "label": "Increase In Fair Value Measurement Due To Change In One Or More Unobservable Inputs To Reflect Reasonably Possible Alternative Assumptions, Assets (Liabilities)",
        "documentation": "The amount of increase in the fair value measurement of assets and liabilities due to a change in one or more unobservable inputs to reflect reasonably possible alternative assumptions."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IncreaseThroughNewLeasesLiabilitiesArisingFromFinancingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseThroughNewLeasesLiabilitiesArisingFromFinancingActivities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofleaseliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "New leases",
        "label": "Increase through new leases, liabilities arising from financing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase in liabilities arising from financing activities resulting from new leases. [Refer: Liabilities arising from financing activities]"
       }
      }
     },
     "auth_ref": [
      "r631",
      "r633"
     ]
    },
    "ifrs-full_IncreaseThroughOriginationOrPurchaseExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseThroughOriginationOrPurchaseExposureToCreditRiskOnLoanCommitmentsAndFinancialGuaranteeContracts",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Business activity in the year",
        "label": "Increase through origination or purchase, exposure to credit risk on loan commitments and financial guarantee contracts"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase in exposure to credit risk on loan commitments and financial guarantee contracts resulting from origination or purchase. [Refer: Exposure to credit risk on loan commitments and financial guarantee contracts]"
       }
      }
     },
     "auth_ref": [
      "r662",
      "r663",
      "r686",
      "r707",
      "r708"
     ]
    },
    "ifrs-full_IncreaseThroughOriginationOrPurchaseFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IncreaseThroughOriginationOrPurchaseFinancialAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Business activity in the year",
        "label": "Increase through origination or purchase, financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase in financial assets resulting from origination or purchase. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r662",
      "r663",
      "r686",
      "r707",
      "r708"
     ]
    },
    "bbplc_IndefinitelyMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IndefinitelyMember",
     "presentation": [
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Indefinitely",
        "label": "Indefinitely [member]",
        "documentation": "This member stands for indefinite carryforward."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IndependentDirectorMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IndependentDirectorMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Independent director",
        "label": "Independent Director [Member]",
        "documentation": "Independent Director"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IndividualAssetsOrCashgeneratingUnitsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IndividualAssetsOrCashgeneratingUnitsAxis",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Individual assets or cash-generating units [axis]",
        "label": "Individual assets or cash-generating units [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r79"
     ]
    },
    "ifrs-full_IndividualAssetsOrCashgeneratingUnitsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IndividualAssetsOrCashgeneratingUnitsDomain",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Individual assets or cash-generating units [domain]",
        "label": "Individual assets or cash-generating units [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the standard value for the 'Individual assets or cash-generating units' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r79"
     ]
    },
    "ifrs-full_IndividualAssetsOrCashgeneratingUnitsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IndividualAssetsOrCashgeneratingUnitsMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total",
        "label": "Total for all individual assets or cash-generating units [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for individual assets or cash-generating units. [Refer: Total for all cash-generating units [member]]"
       }
      }
     },
     "auth_ref": [
      "r79"
     ]
    },
    "ifrs-full_IndividualAssetsOrCashgeneratingUnitsWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IndividualAssetsOrCashgeneratingUnitsWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesAxis",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash-generating units [axis]",
        "label": "Cash-generating units [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r86",
      "r439"
     ]
    },
    "ifrs-full_IndividualAssetsOrCashgeneratingUnitsWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IndividualAssetsOrCashgeneratingUnitsWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesDomain",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash-generating units [domain]",
        "label": "Cash-generating units [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the standard value for the 'Cash-generating units' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r86",
      "r90",
      "r439",
      "r441"
     ]
    },
    "ifrs-full_IndividualAssetsOrCashgeneratingUnitsWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IndividualAssetsOrCashgeneratingUnitsWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total for all cash-generating units",
        "label": "Total for all cash-generating units [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the smallest identifiable group of assets that generates cash inflows that are largely independent of the cash inflows from other assets or groups of assets."
       }
      }
     },
     "auth_ref": [
      "r86",
      "r439"
     ]
    },
    "ecd_IndividualAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "IndividualAxis",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure",
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure",
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements",
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Individual [Axis]",
        "terseLabel": "Individual:"
       }
      }
     },
     "auth_ref": [
      "r747",
      "r758",
      "r768",
      "r792",
      "r801",
      "r805",
      "r813"
     ]
    },
    "bbplc_InflationRiskMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "InflationRiskMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Inflation risk",
        "label": "Inflation Risk [Member]",
        "documentation": "This member stands for the inflation risk factor."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_InformationAboutCollateralHeldAsSecurityAndOtherCreditEnhancementsForCreditimpairedFinancialAssetsExplanatory": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InformationAboutCollateralHeldAsSecurityAndOtherCreditEnhancementsForCreditimpairedFinancialAssetsExplanatory",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of collateral held as security for assets",
        "label": "Information about collateral held as security and other credit enhancements for credit-impaired financial assets [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of information about the collateral held as security and other credit enhancements (for example, quantification of the extent to which collateral and other credit enhancements mitigate credit risk) for financial assets that are credit-impaired at the reporting date."
       }
      }
     },
     "auth_ref": [
      "r290"
     ]
    },
    "bbplc_InfrastructureAdministrationAndGeneralExpenses": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "InfrastructureAdministrationAndGeneralExpenses",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total infrastructure, administration and general expenses",
        "label": "Infrastructure, Administration And General Expenses",
        "documentation": "Infrastructure, Administration And General Expenses"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_InfrastructureAmountContributedToFairValueOfPlanAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "InfrastructureAmountContributedToFairValueOfPlanAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails": {
       "parentTag": "ifrs-full_PlanAssetsAtFairValue",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Infrastructure",
        "label": "Infrastructure, Amount Contributed To Fair Value Of Plan Assets",
        "documentation": "The amount of infrastructure contributed to the fair value of defined benefit plan assets."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_InfrastructureCosts": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "InfrastructureCosts",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails": {
       "parentTag": "bbplc_InfrastructureAdministrationAndGeneralExpenses",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_OperatingExpense",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Infrastructure costs",
        "totalLabel": "Total infrastructure costs",
        "label": "Infrastructure Costs",
        "documentation": "The amount of infrastructure costs incurred by the entity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_InfrastructureCostsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "InfrastructureCostsAbstract",
     "presentation": [
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Infrastructure costs",
        "label": "Infrastructure Costs [Abstract]",
        "documentation": "Infrastructure Costs"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_InputsAssumptionsAndEstimationTechniquesUsedToDetermineExpectedCreditLossesProbability": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "InputsAssumptionsAndEstimationTechniquesUsedToDetermineExpectedCreditLossesProbability",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Inputs, assumptions and estimation techniques used for ECL, probability",
        "label": "Inputs, Assumptions And Estimation Techniques Used To Determine Expected Credit Losses, Probability",
        "documentation": "Inputs, Assumptions And Estimation Techniques Used To Determine Expected Credit Losses, Probability"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_InsiderTradingArrLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "InsiderTradingArrLineItems",
     "lang": {
      "en-us": {
       "role": {
        "label": "Insider Trading Arrangements [Line Items]",
        "terseLabel": "Insider Trading Arrangements:"
       }
      }
     },
     "auth_ref": [
      "r811"
     ]
    },
    "ecd_InsiderTradingPoliciesProcLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "InsiderTradingPoliciesProcLineItems",
     "lang": {
      "en-us": {
       "role": {
        "label": "Insider Trading Policies and Procedures [Line Items]",
        "terseLabel": "Insider Trading Policies and Procedures:"
       }
      }
     },
     "auth_ref": [
      "r728",
      "r817"
     ]
    },
    "ecd_InsiderTrdPoliciesProcAdoptedFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "InsiderTrdPoliciesProcAdoptedFlag",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Insider Trading Policies and Procedures Adopted [Flag]",
        "terseLabel": "Insider Trading Policies and Procedures Adopted"
       }
      }
     },
     "auth_ref": [
      "r728",
      "r817"
     ]
    },
    "ecd_InsiderTrdPoliciesProcNotAdoptedTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "InsiderTrdPoliciesProcNotAdoptedTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Insider Trading Policies and Procedures Not Adopted [Text Block]",
        "terseLabel": "Insider Trading Policies and Procedures Not Adopted"
       }
      }
     },
     "auth_ref": [
      "r728",
      "r817"
     ]
    },
    "ifrs-full_IntangibleAssetsAndGoodwill": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IntangibleAssetsAndGoodwill",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails": {
       "parentTag": "ifrs-full_RecoverableAmountOfAssetOrCashgeneratingUnit",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 13.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Goodwill and intangible assets",
        "periodStartLabel": "Intangible assets and goodwill, beginning of period",
        "periodEndLabel": "Intangible assets and goodwill, end of period",
        "totalLabel": "Carrying value",
        "label": "Intangible assets and goodwill"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of intangible assets and goodwill held by the entity. [Refer: Goodwill; Intangible assets other than goodwill]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_IntangibleAssetsAndGoodwillAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IntangibleAssetsAndGoodwillAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Intangible assets and goodwill [abstract]",
        "label": "Intangible assets and goodwill [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IntangibleAssetsAndGoodwillSensitiveToChangesInKeyVariables": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IntangibleAssetsAndGoodwillSensitiveToChangesInKeyVariables",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Carrying value",
        "label": "Intangible Assets And Goodwill, Sensitive To Changes In Key Variables",
        "documentation": "Intangible Assets And Goodwill, Sensitive To Changes In Key Variables"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IntangibleAssetsOtherThanGoodwill": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IntangibleAssetsOtherThanGoodwill",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails": {
       "parentTag": "ifrs-full_NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSale",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails": {
       "parentTag": "ifrs-full_IntangibleAssetsAndGoodwill",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Intangible assets",
        "label": "Intangible assets other than goodwill"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of identifiable non-monetary assets without physical substance. This amount does not include goodwill. [Refer: Goodwill]"
       }
      }
     },
     "auth_ref": [
      "r103",
      "r452",
      "r566"
     ]
    },
    "bbplc_IntelligentProcessingSolutionsLimitedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IntelligentProcessingSolutionsLimitedMember",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Intelligent Processing Solutions Limited",
        "label": "Intelligent Processing Solutions Limited [Member]",
        "documentation": "Intelligent Processing Solutions Limited"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_InterestExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestExpense",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_InterestRevenueExpense",
       "weight": -1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Interest and similar expense",
        "negatedTotalLabel": "Interest and similar expense",
        "label": "Interest expense"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of expense arising from interest."
       }
      }
     },
     "auth_ref": [
      "r151",
      "r331",
      "r340"
     ]
    },
    "ifrs-full_InterestExpenseIncomeNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestExpenseIncomeNetDefinedBenefitLiabilityAsset",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofincomestatementchargeDetails": {
       "parentTag": "ifrs-full_IncreaseDecreaseInNetDefinedBenefitLiabilityAsset",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofincomestatementchargeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net finance income",
        "negatedTerseLabel": "Interest costs or income on scheme liabilities or assets",
        "label": "Increase (decrease) in net defined benefit liability (asset) resulting from interest expense (income)"
       }
      }
     },
     "auth_ref": [
      "r24",
      "r408"
     ]
    },
    "ifrs-full_InterestExpenseOnBorrowings": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestExpenseOnBorrowings",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails": {
       "parentTag": "ifrs-full_InterestExpense",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Subordinated liabilities",
        "label": "Interest expense on borrowings"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "bbplc_InterestExpenseOnCashCollateral": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "InterestExpenseOnCashCollateral",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails": {
       "parentTag": "ifrs-full_InterestExpense",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Cash collateral",
        "label": "Interest Expense On Cash Collateral",
        "documentation": "Interest Expense On Cash Collateral"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_InterestExpenseOnDebtInstrumentsIssued": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestExpenseOnDebtInstrumentsIssued",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails": {
       "parentTag": "ifrs-full_InterestExpense",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Debt securities in issue",
        "label": "Interest expense on debt instruments issued"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "bbplc_InterestExpenseOnDepositsAtAmortisedCost": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "InterestExpenseOnDepositsAtAmortisedCost",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails": {
       "parentTag": "ifrs-full_InterestExpense",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Deposits at amortised cost from banks and customers",
        "label": "Interest Expense On Deposits At Amortised Cost",
        "documentation": "The amount of interest expense on deposits at amortised cost."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_InterestExpenseOnLeaseLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestExpenseOnLeaseLiabilities",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofleaseliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Interest expense",
        "label": "Interest expense on lease liabilities"
       }
      }
     },
     "auth_ref": [
      "r190",
      "r363"
     ]
    },
    "ifrs-full_InterestExpenseOnOtherFinancialLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestExpenseOnOtherFinancialLiabilities",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails": {
       "parentTag": "ifrs-full_InterestExpense",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Other",
        "label": "Interest expense on other financial liabilities"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "bbplc_InterestIncome1Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "InterestIncome1Member",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Recycled to net interest income",
        "label": "Interest Income1 [Member]",
        "documentation": "This member stands for the amount of income arising from interest."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_InterestIncomeForCashCollateral": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "InterestIncomeForCashCollateral",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails": {
       "parentTag": "ifrs-full_InterestRevenueCalculatedUsingEffectiveInterestMethod",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash collateral",
        "label": "Interest Income For Cash Collateral",
        "documentation": "Interest Income For Cash Collateral"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_InterestIncomeForFinancialAssetsMeasuredAtAmortisedCost": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestIncomeForFinancialAssetsMeasuredAtAmortisedCost",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails": {
       "parentTag": "ifrs-full_InterestRevenueCalculatedUsingEffectiveInterestMethod",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans and advances at amortised cost to banks and customers",
        "label": "Interest revenue for financial assets measured at amortised cost"
       }
      }
     },
     "auth_ref": [
      "r250",
      "r488"
     ]
    },
    "ifrs-full_InterestIncomeOnCashAndBankBalancesAtCentralBanks": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestIncomeOnCashAndBankBalancesAtCentralBanks",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails": {
       "parentTag": "ifrs-full_InterestRevenueCalculatedUsingEffectiveInterestMethod",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash and balances at central banks",
        "label": "Interest income on cash and bank balances at central banks"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "ifrs-full_InterestIncomeOnOtherFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestIncomeOnOtherFinancialAssets",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails": {
       "parentTag": "ifrs-full_InterestRevenueCalculatedUsingEffectiveInterestMethod",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other",
        "label": "Interest income on other financial assets"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "ifrs-full_InterestPaidClassifiedAsFinancingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestPaidClassifiedAsFinancingActivities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequityParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Interest paid, classified as financing activities",
        "label": "Interest paid, classified as financing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash outflow for interest paid, classified as financing activities."
       }
      }
     },
     "auth_ref": [
      "r121"
     ]
    },
    "ifrs-full_InterestPaidClassifiedAsOperatingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestPaidClassifiedAsOperatingActivities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/ConsolidatedcashflowstatementParenthetical",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatementParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Interest paid, classified as operating activities",
        "label": "Interest paid, classified as operating activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash outflow for interest paid, classified as operating activities."
       }
      }
     },
     "auth_ref": [
      "r121"
     ]
    },
    "ifrs-full_InterestRateBenchmarksAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestRateBenchmarksAxis",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Interest rate benchmarks [axis]",
        "label": "Interest rate benchmarks [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r273"
     ]
    },
    "ifrs-full_InterestRateBenchmarksDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestRateBenchmarksDomain",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Interest rate benchmarks [domain]",
        "label": "Interest rate benchmarks [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all interest rate benchmarks. It also represents the standard value for the 'Interest rate benchmarks' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r273"
     ]
    },
    "ifrs-full_InterestRateMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestRateMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Interest rate volatility",
        "label": "Interest rate, measurement input [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for an interest rate used as a measurement input."
       }
      }
     },
     "auth_ref": [
      "r643"
     ]
    },
    "ifrs-full_InterestRateRiskMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestRateRiskMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Interest rate risk",
        "verboseLabel": "Interest rate derivatives",
        "label": "Interest rate risk [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the type of risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in market interest rates. [Refer: Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r203",
      "r204",
      "r205",
      "r207",
      "r328"
     ]
    },
    "bbplc_InterestRateSwapAndCreditDefaultSwapUSCivilActionsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "InterestRateSwapAndCreditDefaultSwapUSCivilActionsMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Interest Rate Swap and Credit Default Swap US Civil Actions",
        "label": "Interest Rate Swap And Credit Default Swap US Civil Actions [Member]",
        "documentation": "Interest Rate Swap And Credit Default Swap US Civil Actions"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_InterestReceivedClassifiedAsOperatingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestReceivedClassifiedAsOperatingActivities",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/ConsolidatedcashflowstatementParenthetical",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatementParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Interest received, classified as operating activities",
        "label": "Interest received, classified as operating activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash inflow from interest received, classified as operating activities."
       }
      }
     },
     "auth_ref": [
      "r121"
     ]
    },
    "ifrs-full_InterestRevenueCalculatedUsingEffectiveInterestMethod": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestRevenueCalculatedUsingEffectiveInterestMethod",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_InterestRevenueExpense",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Interest and similar income",
        "totalLabel": "Interest and similar income",
        "label": "Interest revenue calculated using effective interest method"
       }
      }
     },
     "auth_ref": [
      "r592",
      "r593"
     ]
    },
    "ifrs-full_InterestRevenueExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestRevenueExpense",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails": {
       "parentTag": "bbplc_OperatingIncome",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "bbplc_OperatingIncome",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Net interest income",
        "terseLabel": "Net interest income",
        "label": "Interest income (expense)"
       }
      }
     },
     "auth_ref": [
      "r335",
      "r340",
      "r887"
     ]
    },
    "ifrs-full_InterestRevenueForFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InterestRevenueForFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails": {
       "parentTag": "ifrs-full_InterestRevenueCalculatedUsingEffectiveInterestMethod",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fair value through other comprehensive income",
        "label": "Interest revenue for financial assets measured at fair value through other comprehensive income"
       }
      }
     },
     "auth_ref": [
      "r250",
      "r488"
     ]
    },
    "bbplc_InterestsInOtherEntitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "InterestsInOtherEntitiesAbstract",
     "lang": {
      "en-us": {
       "role": {
        "label": "Interests In Other Entities [Abstract]",
        "documentation": "Interests In Other Entities [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_InternalCreditGradesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InternalCreditGradesAxis",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Internal credit grades [axis]",
        "label": "Internal credit grades [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r668",
      "r687",
      "r713"
     ]
    },
    "ifrs-full_InternalCreditGradesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InternalCreditGradesDomain",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Internal credit grades [domain]",
        "label": "Internal credit grades [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the standard value for the 'Internal credit grades' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r668",
      "r687",
      "r713"
     ]
    },
    "ifrs-full_InternalCreditGradesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InternalCreditGradesMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total for all internal credit grades",
        "label": "Total for all internal credit grades [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for credit grades that have been developed by the entity itself."
       }
      }
     },
     "auth_ref": [
      "r668",
      "r687",
      "r713"
     ]
    },
    "ifrs-full_InternallyGeneratedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InternallyGeneratedMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Internally generated",
        "label": "Internally generated [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for items that have been internally generated by the entity."
       }
      }
     },
     "auth_ref": [
      "r104",
      "r453"
     ]
    },
    "ifrs-full_InvestmentAccountedForUsingEquityMethod": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InvestmentAccountedForUsingEquityMethod",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 11.0
      },
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresDisclosureofinvestmentsinassociatesandjointventuresDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresDisclosureofinvestmentsinassociatesandjointventuresDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Investments in associates and joint ventures",
        "terseLabel": "Investments in associates and joint ventures",
        "totalLabel": "Total investments accounted for using equity method",
        "label": "Investments accounted for using equity method"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of investments accounted for using the equity method. The equity method is a method of accounting whereby the investment is initially recognised at cost and adjusted thereafter for the post-acquisition change in the investor's share of net assets of the investee. The investor's profit or loss includes its share of the profit or loss of the investee. The investor's other comprehensive income includes its share of the other comprehensive income of the investee. [Refer: At cost [member]]"
       }
      }
     },
     "auth_ref": [
      "r156",
      "r336",
      "r529",
      "r568"
     ]
    },
    "ifrs-full_InvestmentFundsAmountContributedToFairValueOfPlanAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InvestmentFundsAmountContributedToFairValueOfPlanAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails": {
       "parentTag": "ifrs-full_PlanAssetsAtFairValue",
       "weight": 1.0,
       "order": 9.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Mixed investment funds",
        "label": "Investment funds, amount contributed to fair value of plan assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount investment funds contribute to the fair value of defined benefit plan assets. [Refer: Plan assets, at fair value; Defined benefit plans [domain]; Investment funds [member]]"
       }
      }
     },
     "auth_ref": [
      "r618"
     ]
    },
    "ifrs-full_InvestmentFundsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InvestmentFundsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Mixed investment funds",
        "label": "Investment funds [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for investment funds."
       }
      }
     },
     "auth_ref": [
      "r638"
     ]
    },
    "ifrs-full_InvestmentProperty": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InvestmentProperty",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails": {
       "parentTag": "ifrs-full_FinancialAssetsAtFairValue",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Investment property",
        "label": "Investment property"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of property (land or a building - or part of a building - or both) held (by the owner or by the lessee as a right-of-use asset) to earn rentals or for capital appreciation or both, rather than for: (a) use in the production or supply of goods or services or for administrative purposes; or (b) sale in the ordinary course of business."
       }
      }
     },
     "auth_ref": [
      "r112",
      "r114",
      "r454",
      "r456",
      "r565"
     ]
    },
    "ifrs-full_InvestmentPropertyMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InvestmentPropertyMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentNarrativeDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Investment property",
        "netLabel": "Property",
        "label": "Investment property [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for investment property. [Refer: Investment property]"
       }
      }
     },
     "auth_ref": [
      "r640",
      "r650"
     ]
    },
    "ifrs-full_InvestmentsInAssociatesAccountedForUsingEquityMethod": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InvestmentsInAssociatesAccountedForUsingEquityMethod",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresDisclosureofinvestmentsinassociatesandjointventuresDetails": {
       "parentTag": "ifrs-full_InvestmentAccountedForUsingEquityMethod",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresDisclosureofinvestmentsinassociatesandjointventuresDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Investments in associates accounted for using equity method",
        "label": "Investments in associates accounted for using equity method"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of investments in associates accounted for using the equity method. [Refer: Total for all associates [member]; Investments accounted for using equity method]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_InvestmentsInJointVenturesAccountedForUsingEquityMethod": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InvestmentsInJointVenturesAccountedForUsingEquityMethod",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresDisclosureofinvestmentsinassociatesandjointventuresDetails": {
       "parentTag": "ifrs-full_InvestmentAccountedForUsingEquityMethod",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresDisclosureofinvestmentsinassociatesandjointventuresDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Investments in joint ventures accounted for using equity method",
        "label": "Investments in joint ventures accounted for using equity method"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of investments in joint ventures accounted for using the equity method. [Refer: Total for all joint ventures [member]; Investments accounted for using equity method]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_InvestmentsInSubsidiaries": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InvestmentsInSubsidiaries",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 12.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Investment in subsidiaries",
        "label": "Investments in subsidiaries reported in separate financial statements"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of investments in subsidiaries in an entity's separate financial statements. [Refer: Total for all subsidiaries [member]]"
       }
      }
     },
     "auth_ref": [
      "r63"
     ]
    },
    "ifrs-full_InvestmentsInSubsidiariesJointVenturesAndAssociatesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "InvestmentsInSubsidiariesJointVenturesAndAssociatesAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Investments in subsidiaries, joint ventures and associates [abstract]",
        "label": "Investments in subsidiaries, joint ventures and associates reported in separate financial statements [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_InvestmentsInSubsidiariesReportedInSeparateFinancialStatementsIncreaseDecrease": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "InvestmentsInSubsidiariesReportedInSeparateFinancialStatementsIncreaseDecrease",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Increase (decrease) in investment in subsidiaries",
        "label": "Investments In Subsidiaries Reported In Separate Financial Statements, Increase (Decrease)",
        "documentation": "Investments in subsidiaries reported in separate financial statements, Increase (Decrease)"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IssuanceCostsOfConvertibleInstruments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IssuanceCostsOfConvertibleInstruments",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Issuance costs",
        "label": "Issuance Costs Of Convertible Instruments",
        "documentation": "Issuance Costs Of Convertible Instruments"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_IssueAndRedemptionOfOtherEquityInstruments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IssueAndRedemptionOfOtherEquityInstruments",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Issue and redemption of other equity instruments",
        "label": "Issue And Redemption Of Other Equity Instruments",
        "documentation": "The increase (decrease) in equity resulting from the issue and exchange of other equity instruments. [Refer: Equity]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IssueOfConvertibleInstruments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IssueOfConvertibleInstruments",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "AT1 securities issuance",
        "label": "Issue of convertible instruments"
       }
      },
      "en": {
       "role": {
        "documentation": "The change in equity resulting from the issuing of convertible instruments."
       }
      }
     },
     "auth_ref": [
      "r879"
     ]
    },
    "bbplc_IssuedCapitalAndSharePremiumMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IssuedCapitalAndSharePremiumMember",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Called up share capital and share premium",
        "label": "Issued Capital And Share Premium [Member]",
        "documentation": "This member stands for the issued capital including the amount received or receivable from issuance of the entity shares in excess of nominal value."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IssuedCapitalMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IssuedCapitalMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Share capital",
        "label": "Issued capital [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a component of equity representing issued capital."
       }
      }
     },
     "auth_ref": [
      "r555"
     ]
    },
    "bbplc_IssuedDebtMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IssuedDebtMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Issued debt",
        "label": "Issued Debt [Member]",
        "documentation": "Issued Debt"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IssuesFairValueMeasurementAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IssuesFairValueMeasurementAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Issues, fair value measurement, assets",
        "label": "Issues, fair value measurement, assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase in the fair value measurement of assets resulting from issues of those assets. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r168"
     ]
    },
    "bbplc_IssuesFairValueMeasurementAssetsLiabilitiesNet": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "IssuesFairValueMeasurementAssetsLiabilitiesNet",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Issues, fair value measurement, assets (liabilities) net",
        "label": "Issues, Fair Value Measurement, Assets (Liabilities), Net",
        "documentation": "The increase in fair value measurement of assets and liabilities resulting from issues of those assets and liabilities. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_IssuesFairValueMeasurementLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "IssuesFairValueMeasurementLiabilities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Issues, fair value measurement, liabilities",
        "label": "Issues, fair value measurement, liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase in fair value measurement of liabilities resulting from issues of those liabilities. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r168"
     ]
    },
    "bbplc_ItalianRetailMarketPortfolioMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ItalianRetailMarketPortfolioMember",
     "presentation": [
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Italian retail market portfolio",
        "label": "Italian Retail Market Portfolio [Member]",
        "documentation": "Italian Retail Market Portfolio"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ItemsInCourseOfTransmissionToOtherBanks": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ItemsInCourseOfTransmissionToOtherBanks",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/OtherliabilitiesDetails": {
       "parentTag": "ifrs-full_OtherLiabilities",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OtherliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Items in the course of collection due to other banks",
        "label": "Items in course of transmission to other banks"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of items that have been transmitted to but not yet received and processed by other banks."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "currency_JPY": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/currency/2025",
     "localname": "JPY",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "netLabel": "JPY",
        "terseLabel": "Japan, Yen",
        "verboseLabel": "JPY",
        "label": "Japan, Yen"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_JointVenturesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "JointVenturesAxis",
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Joint ventures [axis]",
        "label": "Joint ventures [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r65",
      "r67",
      "r158",
      "r523"
     ]
    },
    "ifrs-full_JointVenturesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "JointVenturesDomain",
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Joint ventures [domain]",
        "label": "Joint ventures [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the standard value for the 'Joint ventures' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r65",
      "r67",
      "r158",
      "r523"
     ]
    },
    "ifrs-full_JointVenturesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "JointVenturesMember",
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Joint ventures",
        "label": "Total for all joint ventures [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for joint arrangements whereby the parties that have joint control of the arrangement have rights to the net assets of the arrangement."
       }
      }
     },
     "auth_ref": [
      "r65",
      "r67",
      "r158",
      "r523"
     ]
    },
    "bbplc_KPMGMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "KPMGMember",
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "KPMG",
        "label": "KPMG [Member]",
        "documentation": "This member stands for the principal auditor Klynveld Peat Marwick Goerdeler."
       }
      }
     },
     "auth_ref": []
    },
    "country_KR": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/country/2025",
     "localname": "KR",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Korea, Republic of",
        "label": "KOREA, REPUBLIC OF"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_KeyManagementPersonnelCompensation": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "KeyManagementPersonnelCompensation",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total remuneration awarded",
        "label": "Key management personnel compensation"
       }
      }
     },
     "auth_ref": [
      "r49",
      "r419"
     ]
    },
    "bbplc_KeyManagementPersonnelCompensationCostsRecognisedForAccountingPurposes": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "KeyManagementPersonnelCompensationCostsRecognisedForAccountingPurposes",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails": {
       "parentTag": "ifrs-full_KeyManagementPersonnelCompensation",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Costs recognised for accounting purposes",
        "label": "Key Management Personnel Compensation Costs Recognised For Accounting Purposes",
        "documentation": "The amount of compensation to key management personnel in the form of costs recognised for accounting purposes"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_KeyManagementPersonnelCompensationOtherLongTermBenefitsDifferenceBetweenAwardsGrantedAndCostsRecognised": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "KeyManagementPersonnelCompensationOtherLongTermBenefitsDifferenceBetweenAwardsGrantedAndCostsRecognised",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails": {
       "parentTag": "ifrs-full_KeyManagementPersonnelCompensation",
       "weight": -1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Other long-term benefits \u2013 difference between awards granted and costs recognised",
        "label": "Key Management Personnel Compensation Other Long-Term Benefits Difference Between Awards Granted And Costs Recognised",
        "documentation": "The amount of compensation to key management personnel in the form of Other long-term benefits - difference between awards granted and costs recognised"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_KeyManagementPersonnelCompensationOtherLongtermBenefits": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "KeyManagementPersonnelCompensationOtherLongtermBenefits",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails": {
       "parentTag": "bbplc_KeyManagementPersonnelCompensationCostsRecognisedForAccountingPurposes",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other long-term benefits",
        "label": "Key management personnel compensation, other long-term employee benefits"
       }
      }
     },
     "auth_ref": [
      "r47"
     ]
    },
    "ifrs-full_KeyManagementPersonnelCompensationPostemploymentBenefits": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "KeyManagementPersonnelCompensationPostemploymentBenefits",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails": {
       "parentTag": "bbplc_KeyManagementPersonnelCompensationCostsRecognisedForAccountingPurposes",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Pension costs",
        "label": "Key management personnel compensation, post-employment benefits"
       }
      }
     },
     "auth_ref": [
      "r46"
     ]
    },
    "bbplc_KeyManagementPersonnelCompensationSecurityChargesEmoluments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "KeyManagementPersonnelCompensationSecurityChargesEmoluments",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails": {
       "parentTag": "bbplc_KeyManagementPersonnelCompensationCostsRecognisedForAccountingPurposes",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Employer social security charges on emoluments",
        "label": "Key Management Personnel Compensation Security Charges Emoluments",
        "documentation": "The amount of compensation to key management personnel in the form of employer social security charges on emoluments."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_KeyManagementPersonnelCompensationSecurityChargesEmolumentsAwarded": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "KeyManagementPersonnelCompensationSecurityChargesEmolumentsAwarded",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails": {
       "parentTag": "ifrs-full_KeyManagementPersonnelCompensation",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Employer social security charges on emoluments",
        "label": "Key Management Personnel Compensation Security Charges Emoluments, Awarded",
        "documentation": "The amount of compensation to key management personnel in the form of employer social security charges awarded on emoluments."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_KeyManagementPersonnelCompensationShareBasedPaymentsDifferenceBetweenAwardsGrantedAndCostsRecognised": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "KeyManagementPersonnelCompensationShareBasedPaymentsDifferenceBetweenAwardsGrantedAndCostsRecognised",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails": {
       "parentTag": "ifrs-full_KeyManagementPersonnelCompensation",
       "weight": -1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Share-based payments \u2013 difference between awards granted and costs recognised",
        "label": "Key Management Personnel Compensation Share-Based Payments Difference Between Awards Granted And Costs Recognised",
        "documentation": "The amount of compensation to key management personnel in the form of Share-based payments - difference between awards granted and costs recognised"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_KeyManagementPersonnelCompensationSharebasedPayment": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "KeyManagementPersonnelCompensationSharebasedPayment",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails": {
       "parentTag": "bbplc_KeyManagementPersonnelCompensationCostsRecognisedForAccountingPurposes",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Share-based payments",
        "label": "Key management personnel compensation, share-based payment"
       }
      }
     },
     "auth_ref": [
      "r48"
     ]
    },
    "ifrs-full_KeyManagementPersonnelCompensationShorttermEmployeeBenefits": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "KeyManagementPersonnelCompensationShorttermEmployeeBenefits",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails": {
       "parentTag": "bbplc_KeyManagementPersonnelCompensationCostsRecognisedForAccountingPurposes",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofremunerationofDirectorsandotherKeyManagementPersonnelDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Salaries and other short-term benefits",
        "label": "Key management personnel compensation, short-term employee benefits"
       }
      }
     },
     "auth_ref": [
      "r45"
     ]
    },
    "ifrs-full_KeyManagementPersonnelOfEntityOrParentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "KeyManagementPersonnelOfEntityOrParentMember",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofloansanddepositsoutstandingDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Key management personnel and connected persons",
        "label": "Key management personnel of entity or parent [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for those persons having authority and responsibility for planning, directing and controlling the activities of the entity, directly or indirectly, including any director (whether executive or otherwise) of that entity."
       }
      }
     },
     "auth_ref": [
      "r56",
      "r426"
     ]
    },
    "country_LU": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/country/2025",
     "localname": "LU",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Luxembourg",
        "label": "LUXEMBOURG"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LandAndBuildingsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LandAndBuildingsMember",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Property",
        "label": "Land and buildings [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a class of property, plant and equipment representing land and depreciable buildings and similar structures for use in operations. [Refer: Buildings; Land; Property, plant and equipment]"
       }
      }
     },
     "auth_ref": [
      "r608"
     ]
    },
    "bbplc_LaterThanElevenYearsAndNotLaterThanTwentyYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LaterThanElevenYearsAndNotLaterThanTwentyYearsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "In years 11 to 20",
        "label": "Later Than Eleven Years And Not Later Than Twenty Years [Member]",
        "documentation": "This member stands for a time band of later than eleven years and not later than twenty years."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LaterThanFiveYearsAndNotLaterThanSixYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LaterThanFiveYearsAndNotLaterThanSixYearsMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "2030",
        "label": "Later Than Five Years And Not Later Than Six Years [Member]",
        "documentation": "This member stands for a time band of later than five years and not later than six years."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LaterThanFiveYearsAndNotLaterThanTenYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LaterThanFiveYearsAndNotLaterThanTenYearsMember",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofmaturityanalysisofleaseliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Five to ten years",
        "label": "Later than five years and not later than ten years [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of later than five years and not later than ten years."
       }
      }
     },
     "auth_ref": [
      "r674",
      "r689",
      "r880"
     ]
    },
    "ifrs-full_LaterThanFiveYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LaterThanFiveYearsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Over five years",
        "label": "Later than five years [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of later than five years."
       }
      }
     },
     "auth_ref": [
      "r196",
      "r197",
      "r210",
      "r370",
      "r373",
      "r674",
      "r683",
      "r689"
     ]
    },
    "ifrs-full_LaterThanFourYearsAndNotLaterThanFiveYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LaterThanFourYearsAndNotLaterThanFiveYearsMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/LeasesDisclosureofmaturityanalysisofleaseliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Four to five years",
        "terseLabel": "2029",
        "label": "Later than four years and not later than five years [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of later than four years and not later than five years."
       }
      }
     },
     "auth_ref": [
      "r196",
      "r197",
      "r210",
      "r674",
      "r689",
      "r880"
     ]
    },
    "ifrs-full_LaterThanOneMonthAndNotLaterThanThreeMonthsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LaterThanOneMonthAndNotLaterThanThreeMonthsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Over one month but not more than three months",
        "label": "Later than one month and not later than three months [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of later than one month and not later than three months."
       }
      }
     },
     "auth_ref": [
      "r673",
      "r678",
      "r689"
     ]
    },
    "ifrs-full_LaterThanOneYearAndNotLaterThanThreeYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LaterThanOneYearAndNotLaterThanThreeYearsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Over one year but not more than three years",
        "label": "Later than one year and not later than three years [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of later than one year and not later than three years."
       }
      }
     },
     "auth_ref": [
      "r674",
      "r681",
      "r689"
     ]
    },
    "ifrs-full_LaterThanOneYearAndNotLaterThanTwoYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LaterThanOneYearAndNotLaterThanTwoYearsMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/LeasesDisclosureofmaturityanalysisofleaseliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "One to two years",
        "terseLabel": "2026",
        "label": "Later than one year and not later than two years [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of later than one year and not later than two years."
       }
      }
     },
     "auth_ref": [
      "r196",
      "r197",
      "r210",
      "r674",
      "r689",
      "r880"
     ]
    },
    "ifrs-full_LaterThanOneYearMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LaterThanOneYearMember",
     "presentation": [
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "After more than 12 months",
        "label": "Later than one year [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of later than one year."
       }
      }
     },
     "auth_ref": [
      "r578"
     ]
    },
    "ifrs-full_LaterThanSixMonthsAndNotLaterThanOneYearMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LaterThanSixMonthsAndNotLaterThanOneYearMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Over six months but not more than one year",
        "label": "Later than six months and not later than one year [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of later than six months and not later than one year."
       }
      }
     },
     "auth_ref": [
      "r674",
      "r680",
      "r689"
     ]
    },
    "bbplc_LaterThanSixYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LaterThanSixYearsMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "2031 and later",
        "label": "Later Than Six Years [member]",
        "documentation": "This member stands for a time band of later than six years."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LaterThanTenYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LaterThanTenYearsMember",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofmaturityanalysisofleaseliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Greater than ten years",
        "label": "Later than ten years [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of later than ten years."
       }
      }
     },
     "auth_ref": [
      "r674",
      "r689",
      "r880"
     ]
    },
    "ifrs-full_LaterThanThreeMonthsAndNotLaterThanSixMonthsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LaterThanThreeMonthsAndNotLaterThanSixMonthsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Over three months but not more than six months",
        "label": "Later than three months and not later than six months [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of later than three months and not later than six months."
       }
      }
     },
     "auth_ref": [
      "r674",
      "r679",
      "r689"
     ]
    },
    "ifrs-full_LaterThanThreeYearsAndNotLaterThanFiveYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LaterThanThreeYearsAndNotLaterThanFiveYearsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Over three years but not more than five years",
        "label": "Later than three years and not later than five years [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of later than three years and not later than five years."
       }
      }
     },
     "auth_ref": [
      "r674",
      "r682",
      "r689"
     ]
    },
    "ifrs-full_LaterThanThreeYearsAndNotLaterThanFourYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LaterThanThreeYearsAndNotLaterThanFourYearsMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/LeasesDisclosureofmaturityanalysisofleaseliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Three to four years",
        "terseLabel": "2028",
        "label": "Later than three years and not later than four years [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of later than three years and not later than four years."
       }
      }
     },
     "auth_ref": [
      "r196",
      "r197",
      "r210",
      "r674",
      "r689",
      "r880"
     ]
    },
    "bbplc_LaterThanTwentyYearsAndNotLaterThanThirtyYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LaterThanTwentyYearsAndNotLaterThanThirtyYearsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "In years 20 to 30",
        "label": "Later Than Twenty Years And Not Later Than Thirty Years [Member]",
        "documentation": "This member stands for a time band of later than twenty years and not later than thirty years."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LaterThanTwoYearsAndNotLaterThanThreeYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LaterThanTwoYearsAndNotLaterThanThreeYearsMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/LeasesDisclosureofmaturityanalysisofleaseliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Two to three years",
        "terseLabel": "2027",
        "label": "Later than two years and not later than three years [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of later than two years and not later than three years."
       }
      }
     },
     "auth_ref": [
      "r196",
      "r197",
      "r210",
      "r674",
      "r689",
      "r880"
     ]
    },
    "bbplc_LeaseExtensionPeriod": {
     "xbrltype": "durationItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LeaseExtensionPeriod",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofleaseliabilitiesDetails",
      "http://www.home.barclays/role/LeasesNarrativeDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Lease, extension period",
        "label": "Lease, Extension Period",
        "documentation": "Lease, Extension Period"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LeaseLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LeaseLiabilities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofleaseliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "periodStartLabel": "Lease liabilities, beginning balance",
        "periodEndLabel": "Lease liabilities, ending balance",
        "label": "Lease liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of liabilities related to the entity's leases. Lease is a contract, or part of a contract, that conveys the right to use an underlying asset for a period of time in exchange for consideration."
       }
      }
     },
     "auth_ref": [
      "r189"
     ]
    },
    "ifrs-full_LeaseLiabilitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LeaseLiabilitiesAbstract",
     "lang": {
      "en-us": {
       "role": {
        "label": "Lease liabilities [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LeaseholdImprovementsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LeaseholdImprovementsMember",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Costs of adaptation of freehold and leasehold property",
        "label": "Leasehold improvements [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a class of property, plant and equipment representing improvements to assets held under a lease agreement."
       }
      }
     },
     "auth_ref": [
      "r838"
     ]
    },
    "bbplc_LeasesLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LeasesLineItems",
     "presentation": [
      "http://www.home.barclays/role/LeasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Leases [Line Items]",
        "label": "Leases [Line Items]",
        "documentation": "Leases [Line Items]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LeasesTable": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LeasesTable",
     "presentation": [
      "http://www.home.barclays/role/LeasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Leases [Table]",
        "label": "Leases [Table]",
        "documentation": "Leases [Table]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LegalProceedingsProvisionAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LegalProceedingsProvisionAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Legal proceedings provision [abstract]",
        "label": "Legal proceedings provision [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LegalProceedingsProvisionMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LegalProceedingsProvisionMember",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Legal, competition and regulatory matters",
        "label": "Legal proceedings provision [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a provision for legal proceedings. [Refer: Classes of other provisions [domain]]"
       }
      }
     },
     "auth_ref": [
      "r624",
      "r625"
     ]
    },
    "ifrs-full_Level1OfFairValueHierarchyMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "Level1OfFairValueHierarchyMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Level 1",
        "verboseLabel": "Quoted",
        "label": "Level 1 of fair value hierarchy [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a category of the fair value hierarchy where inputs to the valuation techniques are quoted prices (unadjusted) in active markets for identical assets or liabilities that the entity can access at the measurement date."
       }
      }
     },
     "auth_ref": [
      "r33",
      "r77",
      "r82",
      "r163",
      "r437",
      "r531"
     ]
    },
    "ifrs-full_Level2And3OfFairValueHierarchyMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "Level2And3OfFairValueHierarchyMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Unquoted",
        "label": "Level 2 and 3 of fair value hierarchy [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for combined Level 2 and Level 3 categories of the fair value hierarchy. [Refer: Level 2 of fair value hierarchy [member]; Level 3 of fair value hierarchy [member]]"
       }
      }
     },
     "auth_ref": [
      "r33"
     ]
    },
    "ifrs-full_Level2OfFairValueHierarchyMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "Level2OfFairValueHierarchyMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Level 2",
        "label": "Level 2 of fair value hierarchy [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a category of the fair value hierarchy where inputs to the valuation techniques are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly."
       }
      }
     },
     "auth_ref": [
      "r77",
      "r82",
      "r163",
      "r437",
      "r531"
     ]
    },
    "ifrs-full_Level3OfFairValueHierarchyMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "Level3OfFairValueHierarchyMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureoffairvalueadjustmentsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Level 3",
        "terseLabel": "Level 3",
        "label": "Level 3 of fair value hierarchy [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a category of the fair value hierarchy where inputs to the valuation techniques are unobservable inputs for the asset or liability. Unobservable inputs are inputs for which market data are not available and that are developed using the best information available about the assumptions that the market participants would use when pricing the asset or liability."
       }
      }
     },
     "auth_ref": [
      "r77",
      "r82",
      "r163",
      "r437",
      "r531"
     ]
    },
    "ifrs-full_LevelsOfFairValueHierarchyAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LevelsOfFairValueHierarchyAxis",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureoffairvalueadjustmentsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Levels of fair value hierarchy [axis]",
        "label": "Levels of fair value hierarchy [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r33",
      "r163",
      "r531"
     ]
    },
    "ifrs-full_LevelsOfFairValueHierarchyDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LevelsOfFairValueHierarchyDomain",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureoffairvalueadjustmentsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Levels of fair value hierarchy [domain]",
        "label": "Levels of fair value hierarchy [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all levels of the fair value hierarchy. It also represents the standard value for the 'Levels of fair value hierarchy' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r33",
      "r163",
      "r531"
     ]
    },
    "ifrs-full_Liabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "Liabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_EquityAndLiabilities",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofamountsincludedintheGroupsfinancialstatementsbycategoryDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total liabilities",
        "verboseLabel": "Total liabilities",
        "terseLabel": "Liabilities",
        "label": "Liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of a present obligation of the entity to transfer an economic resource as a result of past events. Economic resource is a right that has the potential to produce economic benefits."
       }
      }
     },
     "auth_ref": [
      "r162",
      "r163",
      "r170",
      "r335",
      "r339",
      "r530",
      "r531",
      "r575"
     ]
    },
    "ifrs-full_LiabilitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LiabilitiesAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Liabilities",
        "verboseLabel": "Liabilities",
        "label": "Liabilities [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LiabilitiesFromSharebasedPaymentTransactions2011": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LiabilitiesFromSharebasedPaymentTransactions2011",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total liability arising from cash-settled share-based payments transactions",
        "label": "Liabilities from share-based payment transactions"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of liabilities arising from share-based payment transactions. Share-based payment transactions are transactions in which the entity: (a) receives goods or services from the supplier of those goods or services (including an employee) in a share-based payment arrangement; or (b) incurs an obligation to settle the transaction with the supplier in a share-based payment arrangement when another group entity receives those goods or services. [Refer: Types of share-based payment arrangements [domain]]"
       }
      }
     },
     "auth_ref": [
      "r227",
      "r471"
     ]
    },
    "ifrs-full_LiabilitiesIncludedInDisposalGroupsClassifiedAsHeldForSale": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LiabilitiesIncludedInDisposalGroupsClassifiedAsHeldForSale",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails": {
       "parentTag": "bbplc_NetAssetsLiabilitiesOrDisposalGroupsClassifiedAsHeldForSale",
       "weight": -1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialLiabilities",
       "weight": 1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 14.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails",
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Liabilities included in disposal group classified as held for sale",
        "negatedTerseLabel": "Liabilities included in disposal groups classified as held for sale",
        "totalLabel": "Total liabilities classified as held for sale",
        "label": "Liabilities included in disposal groups classified as held for sale"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of liabilities included in disposal groups classified as held for sale. [Refer: Liabilities; Disposal groups classified as held for sale [member]]"
       }
      }
     },
     "auth_ref": [
      "r234",
      "r574"
     ]
    },
    "bbplc_LiabilitiesIncludedInDisposalGroupsClassifiedAsHeldForSaleUndiscountedCashFlows": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LiabilitiesIncludedInDisposalGroupsClassifiedAsHeldForSaleUndiscountedCashFlows",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails": {
       "parentTag": "bbplc_TotalFinancialLiabilitiesUndiscounted",
       "weight": 1.0,
       "order": 7.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Liabilities included in disposal groups classified as held for sale, undiscounted",
        "label": "Liabilities Included in Disposal Groups Classified as Held For Sale, Undiscounted Cash Flows",
        "documentation": "Liabilities Included in Disposal Groups Classified as Held For Sale, Undiscounted Cash Flows"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LiabilitiesMeasuredAtFairValueAndIssuedWithInseparableThirdpartyCreditEnhancementAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LiabilitiesMeasuredAtFairValueAndIssuedWithInseparableThirdpartyCreditEnhancementAxis",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Liabilities measured at fair value and issued with inseparable third-party credit enhancement [axis]",
        "label": "Liabilities measured at fair value and issued with inseparable third-party credit enhancement [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r175"
     ]
    },
    "ifrs-full_LiabilitiesMeasuredAtFairValueAndIssuedWithInseparableThirdpartyCreditEnhancementDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LiabilitiesMeasuredAtFairValueAndIssuedWithInseparableThirdpartyCreditEnhancementDomain",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Liabilities measured at fair value and issued with inseparable third-party credit enhancement [domain]",
        "label": "Liabilities measured at fair value and issued with inseparable third-party credit enhancement [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for liabilities measured at fair value and issued with inseparable third-party credit enhancement. It also represents the standard value for the 'Liabilities measured at fair value and issued with inseparable third-party credit enhancement' axis if no other member is used. [Refer: Liabilities; At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r175"
     ]
    },
    "ifrs-full_LiabilityAssetOfDefinedBenefitPlans": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LiabilityAssetOfDefinedBenefitPlans",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedPeriodStartLabel": "Net defined benefit liability (asset), beginning of period",
        "negatedPeriodEndLabel": "Net defined benefit liability (asset), end of period",
        "terseLabel": "Net defined benefit liability (asset)",
        "label": "Net defined benefit liability (asset)"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of deficit or surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r22",
      "r406"
     ]
    },
    "bbplc_LicencesAndOtherMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LicencesAndOtherMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Licences and other",
        "label": "Licences And Other [Member]",
        "documentation": "This member stands for a class of intangible assets representing the right to use certain intangible assets owned by another entity, including other."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LifeExpectancyAt60ForCurrentPensionersFemalesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LifeExpectancyAt60ForCurrentPensionersFemalesMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Life expectancy at 60 for current pensioners, females",
        "label": "Life Expectancy At 60 For Current Pensioners, Females [Member]",
        "documentation": "This member stands for life expectancy of females at 60 for current pensioners, used as actuarial assumptions."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LifeExpectancyAt60ForCurrentPensionersMalesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LifeExpectancyAt60ForCurrentPensionersMalesMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Life expectancy at 60 for current pensioners, males",
        "label": "Life Expectancy At 60 For Current Pensioners, Males [Member]",
        "documentation": "This member stands for life expectancy of males at 60 for current pensioners, used as actuarial assumptions."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LifeExpectancyAt60ForFuturePensionersAt40YearsFemalesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LifeExpectancyAt60ForFuturePensionersAt40YearsFemalesMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Life expectancy at 40 for future pensioners at 40 years, females",
        "label": "Life Expectancy At 60 For Future Pensioners At 40 Years, Females [Member]",
        "documentation": "This member stands for life expectancy of females at 60 for future pensioners currently aged 40, used as actuarial assumptions."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LifeExpectancyAt60ForFuturePensionersAt40YearsMalesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LifeExpectancyAt60ForFuturePensionersAt40YearsMalesMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Life expectancy at 40 for future pensioners at 40 years, males",
        "label": "Life Expectancy At 60 For Future Pensioners At 40 Years, Males [Member]",
        "documentation": "This member stands for life expectancy of males at 60 for future pensioners currently aged 40, used as actuarial assumptions."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LifeExpectancyAt60ForRemainingPopulationOfTheMembershipMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LifeExpectancyAt60ForRemainingPopulationOfTheMembershipMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Life Expectancy At 60 For Remaining Population Of The Membership",
        "label": "Life Expectancy At 60 For Remaining Population Of The Membership [Member]",
        "documentation": "Life Expectancy At 60 For Remaining Population Of The Membership"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LifeExpectancyPercentageOfPopulationOfTheMembership": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LifeExpectancyPercentageOfPopulationOfTheMembership",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Mortality assumption, percentage",
        "label": "Life Expectancy, Percentage Of Population Of The Membership",
        "documentation": "Life Expectancy, Percentage Of Population Of The Membership"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LifetimeExpectedCreditLossesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LifetimeExpectedCreditLossesMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Lifetime expected credit losses",
        "label": "Lifetime expected credit losses [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the expected credit losses that result from all possible default events over the expected life of a financial instrument. [Refer: Type of measurement of expected credit losses [domain]]"
       }
      }
     },
     "auth_ref": [
      "r284",
      "r295",
      "r510",
      "r516"
     ]
    },
    "bbplc_LiquidatingDistributionsSubjectToTheRankingOfReserveCapitalInstruments": {
     "xbrltype": "perShareItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LiquidatingDistributionsSubjectToTheRankingOfReserveCapitalInstruments",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Liquidating distributions subject to the ranking of reserve capital instruments (EUR/ USD per share)",
        "label": "Liquidating Distributions Subject To The Ranking Of Reserve Capital Instruments",
        "documentation": "The amount of liquidating distributions per share, subject to the ranking of reserve capital instruments, entitled to holders of preference shares are entitled to receive. This includes an amount equal to the accrued dividend for the then current dividend period to the date of the commencement of the winding-up or other such return of capital. If a dividend is not paid in full on any preference shares on any dividend payment date, then a dividend restriction shall apply. This dividend restriction will mean that neither the entity nor the parent company may (a) declare or pay a dividend (other than payment by the parent company of a final dividend declared by its shareholders prior to the relevant dividend payment date, or a dividend paid by Barclays Bank PLC to Barclays PLC or to a wholly owned subsidiary) on any of their respective ordinary shares, other preference shares or other share capital or (b) redeem, purchase, reduce or otherwise acquire any of their respective share capital, other than shares of the entity held by the parent company or a wholly owned subsidiary, until the earlier of: (1) the date on which the entity next declares and pays in full a preference dividend; and (2) the date on or by which all the preference shares are redeemed in full or purchased by the entity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LitigationSettlementsApprovedValue": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LitigationSettlementsApprovedValue",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Litigation settlements approved",
        "label": "Litigation Settlements Approved, Value",
        "documentation": "The amount of litigation settlements approved or agreed upon."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LoanAssetsReclassifiedToBonds": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LoanAssetsReclassifiedToBonds",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reclassification of loan asset",
        "label": "Loan Assets Reclassified To Bonds",
        "documentation": "Loan Assets Reclassified To Bonds"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LoanCommitmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LoanCommitmentsMember",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "netLabel": "Loan commitments",
        "verboseLabel": "Loan liabilities",
        "terseLabel": "Commitments",
        "label": "Loan commitments [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for firm commitments to provide credit under pre-specified terms and conditions."
       }
      }
     },
     "auth_ref": [
      "r296",
      "r326",
      "r512",
      "r517"
     ]
    },
    "bbplc_LoanSpreadMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LoanSpreadMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loan spread",
        "label": "Loan Spread, Measurement Input [Member]",
        "documentation": "Loan Spread, Measurement Input"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LoansAndAdvances": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LoansAndAdvances",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails": {
       "parentTag": "ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLoss",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredNarrativeDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans and advances",
        "label": "Loans and advances"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of loans and advances the entity has made."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_LoansAndAdvancesAndDebtSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LoansAndAdvancesAndDebtSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans and advances at amortised cost",
        "label": "Loans And Advances And Debt Securities [Member]",
        "documentation": "Loans And Advances And Debt Securities"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LoansAndAdvancesAtAmortisedCost": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LoansAndAdvancesAtAmortisedCost",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 5.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialAssets",
       "weight": 1.0,
       "order": 9.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans and advances at amortised cost",
        "verboseLabel": "Loans and advances at amortised cost to banks and customers",
        "label": "Loans and advances at amortised cost"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of loans and advances the entity has made at amortised cost. [Refer: Loans and advances; Financial assets at amortised cost]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_LoansAndAdvancesAtAmortisedCostIncludingDebtSecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LoansAndAdvancesAtAmortisedCostIncludingDebtSecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total loans and advances at amortised cost including debt securities",
        "label": "Loans And Advances At Amortised Cost, Including Debt Securities [Member]",
        "documentation": "Loans And Advances At Amortised Cost, Including Debt Securities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LoansAndAdvancesAtAmortisedCostPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LoansAndAdvancesAtAmortisedCostPercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans and advances at amortised cost, percentage",
        "label": "Loans And Advances At Amortised Cost, Percentage",
        "documentation": "The amount loans and advances at amortised cost, expressed as a percentage."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LoansAndAdvancesDebtSecuritiesAndLoanCommitmentsAndFinancialGuaranteeContractsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LoansAndAdvancesDebtSecuritiesAndLoanCommitmentsAndFinancialGuaranteeContractsMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total loans and advances at amortised cost and Off-balance sheet loan commitments and financial guarantee contracts",
        "label": "Loans And Advances, Debt Securities And Loan Commitments And Financial Guarantee Contracts [Member]",
        "documentation": "Loans And Advances, Debt Securities And Loan Commitments And Financial Guarantee Contracts"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LoansAndAdvancesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LoansAndAdvancesMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans and advances",
        "label": "Loans And Advances [Member]",
        "documentation": "Loans And Advances"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LoansAndAdvancesToBanksAtAmortisedCost": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LoansAndAdvancesToBanksAtAmortisedCost",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans and advances at amortised cost to banks",
        "label": "Loans and advances to banks at amortised cost"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of loans and advances the entity has made to banks at amortised cost. [Refer: Loans and advances to banks; Financial assets at amortised cost]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_LoansAndAdvancesToCustomers": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LoansAndAdvancesToCustomers",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails": {
       "parentTag": "ifrs-full_NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSale",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Loans and advances to customers",
        "label": "Loans and advances to customers"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of loans and advances the entity has made to customers."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_LoansAndAdvancesToCustomersAtAmortisedCost": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LoansAndAdvancesToCustomersAtAmortisedCost",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans and advances at amortised cost to customers",
        "label": "Loans and advances to customers at amortised cost"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of loans and advances the entity has made to customers at amortised cost. [Refer: Loans and advances to customers; Financial assets at amortised cost]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_LoansAndReceivablesCategoryMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LoansAndReceivablesCategoryMember",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcarryingamountoftheassetspledgedassecurityagainstliabilitiesDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughothercomprehensiveincomeDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails",
      "http://www.home.barclays/role/NetinterestincomeSummaryofnetinterestincomeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans and advances at amortised cost",
        "verboseLabel": "Loans and advances",
        "label": "Loans and receivables, category [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the loans and receivables category of financial assets. [Refer: Loans and receivables]"
       }
      }
     },
     "auth_ref": [
      "r547"
     ]
    },
    "ifrs-full_LoansToGovernmentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LoansToGovernmentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Government and Government sponsored debt",
        "label": "Loans to government [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for loans made to government."
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "dei_LocalPhoneNumber": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "LocalPhoneNumber",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Local Phone Number",
        "label": "Local Phone Number",
        "documentation": "Local phone number for entity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LongevityReinsuranceContractsPercentageOfCurrentPensionerLiabilitiesCovered": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LongevityReinsuranceContractsPercentageOfCurrentPensionerLiabilitiesCovered",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Percentage of current pensioner liabilities covered",
        "label": "Longevity Reinsurance Contracts, Percentage Of Current Pensioner Liabilities Covered",
        "documentation": "Longevity Reinsurance Contracts, Percentage Of Current Pensioner Liabilities Covered"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LongevityReinuranceContratNettingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LongevityReinuranceContratNettingMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Longevity reinsurance contracts",
        "label": "Longevity Reinurance Contrat, Netting [Member]",
        "documentation": "Longevity Reinurance Contrat, Netting"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LossContingencyDamagesSoughtClaimedAmountsValue": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LossContingencyDamagesSoughtClaimedAmountsValue",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Damages sought",
        "label": "Loss Contingency, Damages Sought, Claimed Amounts, Value",
        "documentation": "The monetary value of the award the plaintiff seeks in the legal matter, in addition to any interest, costs, and punitive damages."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_LossInCurrentOrPriorYearMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "LossInCurrentOrPriorYearMember",
     "presentation": [
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loss in current or prior year",
        "label": "Loss In Current Or Prior Year [Member]",
        "documentation": "This member stands for loss suffered in either the current or prior year."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_LossesOnLitigationSettlements": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "LossesOnLitigationSettlements",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails": {
       "parentTag": "ifrs-full_OperatingExpense",
       "weight": 1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_OperatingExpense",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Litigation and conduct",
        "label": "Losses on litigation settlements"
       }
      }
     },
     "auth_ref": [
      "r604"
     ]
    },
    "ifrs-full_MajorComponentsOfTaxExpenseIncomeAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MajorComponentsOfTaxExpenseIncomeAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Major components of tax expense (income) [abstract]",
        "label": "Major components of tax expense (income) [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "srt_MajorCustomersAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "MajorCustomersAxis",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Customer [Axis]",
        "label": "Customer [Axis]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ManagementAdjustmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ManagementAdjustmentsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Management adjustments",
        "label": "Management Adjustments [Member]",
        "documentation": "Management Adjustments"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ManagementAndAdvisoryServicesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ManagementAndAdvisoryServicesMember",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Advisory",
        "label": "Management And Advisory Services [Member]",
        "documentation": "This member stands for fees from asset management services and advisory services related to mergers, acquisitions and financial restructuring."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ManagementValueAtRiskTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ManagementValueAtRiskTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of management Value at Risk",
        "label": "Management Value At Risk [Table Text Block]",
        "documentation": "The tabular disclosure of the daily average, maximum and minimum values of management value at risk."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_MandatoryReserveDepositsAtCentralBanks": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MandatoryReserveDepositsAtCentralBanks",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/ConsolidatedcashflowstatementParenthetical",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatementParenthetical",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Balances with banks and other regulatory authorities",
        "label": "Mandatory reserve deposits at central banks"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of reserve that is kept in deposit at a central bank to fulfil regulatory reserve requirements."
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "bbplc_ManufacturingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ManufacturingMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Manufacturing",
        "label": "Manufacturing [member]",
        "documentation": "This member stands for the manufacturing industry."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_MarketComparablePricesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MarketComparablePricesMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Comparable pricing",
        "label": "Market comparable prices [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a specific valuation technique consistent with the market approach that involves analysing inputs from comparable prices (for example, price per square metre) in the current market. [Refer: Market approach [member]]"
       }
      }
     },
     "auth_ref": [
      "r648",
      "r651"
     ]
    },
    "bbplc_MaterialsAndBuildingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "MaterialsAndBuildingMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Materials and Building",
        "label": "Materials And Building [Member]",
        "documentation": "Materials And Building"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_MaturityAnalysisForNonderivativeFinancialLiabilities": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MaturityAnalysisForNonderivativeFinancialLiabilities",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of contractual maturity of financial liabilities - undiscounted",
        "label": "Disclosure of maturity analysis for non-derivative financial liabilities [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of a maturity analysis for non-derivative financial liabilities (including issued financial guarantee contracts) that shows the remaining contractual maturities. [Refer: Derivative financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r298",
      "r518"
     ]
    },
    "bbplc_MaturityAnalysisOfOffBalanceSheetCommitmentsGivenTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "MaturityAnalysisOfOffBalanceSheetCommitmentsGivenTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of maturity analysis of off-balance sheet commitments given",
        "label": "Maturity Analysis Of Off-Balance Sheet Commitments Given [Table Text Block]",
        "documentation": "The tabular disclosure of the maturity split of the off balance sheet commitments given at the balance sheet date. The amounts disclosed in the table are the undiscounted cash flows (i.e. nominal values) on the basis of earliest opportunity at which they are available."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_MaturityAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MaturityAxis",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/LeasesDisclosureofmaturityanalysisofleaseliabilitiesDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ProvisionsNarrativeDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Maturity [axis]",
        "label": "Maturity [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r184",
      "r196",
      "r197",
      "r200",
      "r201",
      "r202",
      "r210",
      "r254",
      "r307",
      "r354",
      "r360",
      "r371",
      "r374",
      "r505",
      "r579",
      "r619",
      "r674"
     ]
    },
    "ifrs-full_MaturityDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MaturityDomain",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/LeasesDisclosureofmaturityanalysisofleaseliabilitiesDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ProvisionsNarrativeDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Maturity [domain]",
        "label": "Maturity [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for aggregated time bands. It also represents the standard value for the 'Maturity' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r184",
      "r196",
      "r197",
      "r200",
      "r201",
      "r202",
      "r210",
      "r254",
      "r354",
      "r360",
      "r371",
      "r374",
      "r505",
      "r579",
      "r619",
      "r674",
      "r684"
     ]
    },
    "bbplc_MaturityPeriod": {
     "xbrltype": "durationItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "MaturityPeriod",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Maturity period",
        "label": "Maturity Period",
        "documentation": "Maturity Period"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_MaximumExposureToCreditRisk": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MaximumExposureToCreditRisk",
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans and advances designated at fair value, attributable to credit risk, maximum exposure",
        "label": "Maximum exposure to credit risk"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount that best represents the maximum exposure to credit risk without taking into account any collateral held or other credit enhancements (for example, netting agreements that do not qualify for offset in accordance with IAS 32). [Refer: Credit risk [member]]"
       }
      }
     },
     "auth_ref": [
      "r289"
     ]
    },
    "ifrs-full_MaximumExposureToLossFromContinuingInvolvement": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MaximumExposureToLossFromContinuingInvolvement",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureofcontinuinginvolvementinfinancialassetsthathavebeenderecognisedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Maximum exposure to loss",
        "label": "Maximum exposure to loss from continuing involvement"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount that best represents the entity's maximum exposure to loss from its continuing involvement in derecognised financial assets."
       }
      }
     },
     "auth_ref": [
      "r306"
     ]
    },
    "ifrs-full_MaximumExposureToLossFromInterestsInStructuredEntities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MaximumExposureToLossFromInterestsInStructuredEntities",
     "calculation": {
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Maximum exposure to loss",
        "label": "Maximum exposure to loss from interests in structured entities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount that best represents the entity's maximum exposure to loss from its interests in structured entities. [Refer: Total for all unconsolidated structured entities [member]]"
       }
      }
     },
     "auth_ref": [
      "r146"
     ]
    },
    "bbplc_MaximumFundingDeficitSecuredByCollateralPool": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "MaximumFundingDeficitSecuredByCollateralPool",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Maximum funding deficit secured by collateral pool",
        "label": "Maximum Funding Deficit Secured By Collateral Pool",
        "documentation": "The maximum funding deficit by which collateral pool has been put in place to provide security."
       }
      }
     },
     "auth_ref": []
    },
    "srt_MaximumMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "MaximumMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Maximum",
        "label": "Maximum [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_MeasureAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "MeasureAxis",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Measure [Axis]",
        "terseLabel": "Measure:"
       }
      }
     },
     "auth_ref": [
      "r784"
     ]
    },
    "ecd_MeasureName": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "MeasureName",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Measure Name",
        "terseLabel": "Name"
       }
      }
     },
     "auth_ref": [
      "r784"
     ]
    },
    "ifrs-full_MeasurementAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MeasurementAxis",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Measurement [axis]",
        "label": "Measurement [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r111",
      "r115",
      "r162",
      "r457",
      "r530"
     ]
    },
    "ifrs-full_MeasurementDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MeasurementDomain",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofassetsandliabilitiesheldatfairvaluedisaggregatedbyvaluationtechniqueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Measurement [domain]",
        "label": "Measurement [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all types of measurement. It also represents the standard value for the 'Measurement' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r111",
      "r115",
      "r162",
      "r457",
      "r530"
     ]
    },
    "bbplc_MemberNominatedDirectorMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "MemberNominatedDirectorMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Member nominated director",
        "label": "Member Nominated Director [Member]",
        "documentation": "Member Nominated Director"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_MethodOfAssessmentOfExpectedCreditLossesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MethodOfAssessmentOfExpectedCreditLossesAxis",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails",
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Method of assessment of expected credit losses [axis]",
        "label": "Method of assessment of expected credit losses [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r662",
      "r667",
      "r686",
      "r707",
      "r712"
     ]
    },
    "ifrs-full_MethodOfAssessmentOfExpectedCreditLossesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MethodOfAssessmentOfExpectedCreditLossesDomain",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails",
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Method of assessment of expected credit losses [domain]",
        "label": "Method of assessment of expected credit losses [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all methods of assessment of expected credit losses. Expected credit losses are the weighted average of credit losses with the respective risks of a default occurring as the weights. This member also represents the standard value for the 'Method of assessment of expected credit losses' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r662",
      "r667",
      "r686",
      "r707",
      "r712"
     ]
    },
    "ifrs-full_MethodsOfGenerationAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MethodsOfGenerationAxis",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Methods of generation [axis]",
        "label": "Methods of generation [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r104",
      "r453"
     ]
    },
    "ifrs-full_MethodsOfGenerationDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MethodsOfGenerationDomain",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Methods of generation [domain]",
        "label": "Methods of generation [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all methods of generation. It also represents the standard value for the 'Methods of generation' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r104",
      "r453"
     ]
    },
    "srt_MinimumMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "MinimumMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Minimum",
        "label": "Minimum [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_MiningAndQuarryingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "MiningAndQuarryingMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Mining and Quarrying",
        "label": "Mining And Quarrying [Member]",
        "documentation": "Mining And Quarrying"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_MiscellaneousOtherOperatingExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MiscellaneousOtherOperatingExpense",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails": {
       "parentTag": "ifrs-full_SellingGeneralAndAdministrativeExpense",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other administration and general expenses",
        "label": "Miscellaneous other operating expense"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "ifrs-full_MiscellaneousOtherProvisionsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MiscellaneousOtherProvisionsMember",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Sundry provisions",
        "label": "Miscellaneous other provisions [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for miscellaneous other provisions. [Refer: Classes of other provisions [domain]]"
       }
      }
     },
     "auth_ref": [
      "r95",
      "r445"
     ]
    },
    "ecd_MnpiDiscTimedForCompValFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "MnpiDiscTimedForCompValFlag",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "MNPI Disclosure Timed for Compensation Value [Flag]",
        "terseLabel": "MNPI Disclosure Timed for Compensation Value"
       }
      }
     },
     "auth_ref": [
      "r804"
     ]
    },
    "ifrs-full_MortgagesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "MortgagesMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Retail mortgages",
        "label": "Mortgages [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a class of financial assets that represents loans to finance the purchase of assets where the asset acts as collateral to secure the loan."
       }
      }
     },
     "auth_ref": [
      "r671",
      "r686",
      "r691"
     ]
    },
    "bbplc_MotorFinanceCommissionArrangementsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "MotorFinanceCommissionArrangementsMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Motor finance commission arrangements",
        "label": "Motor Finance Commission Arrangements [Member]",
        "documentation": "Motor Finance Commission Arrangements"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_MtrlTermsOfTrdArrTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "MtrlTermsOfTrdArrTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Material Terms of Trading Arrangement [Text Block]",
        "terseLabel": "Material Terms of Trading Arrangement"
       }
      }
     },
     "auth_ref": [
      "r812"
     ]
    },
    "bbplc_MultiPeriodExcessEBITDAMethodMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "MultiPeriodExcessEBITDAMethodMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Multi-Period Excess EBITDA Method",
        "label": "Multi-Period Excess EBITDA Method [Member]",
        "documentation": "Multi-Period Excess EBITDA Method"
       }
      }
     },
     "auth_ref": []
    },
    "country_NL": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/country/2025",
     "localname": "NL",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Netherlands",
        "label": "NETHERLANDS"
       }
      }
     },
     "auth_ref": []
    },
    "currency_NOK": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/currency/2025",
     "localname": "NOK",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "NOK",
        "label": "Norway, Krone"
       }
      }
     },
     "auth_ref": []
    },
    "srt_NameOfMajorCustomerDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "NameOfMajorCustomerDomain",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Customer [Domain]",
        "label": "Customer [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_NamedExecutiveOfficersFnTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "NamedExecutiveOfficersFnTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Named Executive Officers, Footnote [Text Block]",
        "terseLabel": "Named Executive Officers, Footnote"
       }
      }
     },
     "auth_ref": [
      "r785"
     ]
    },
    "ifrs-full_NetAssetsLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NetAssetsLiabilities",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "periodStartLabel": "Beginning balance, Assets (liabilities) net",
        "periodEndLabel": "Ending balance, Assets (liabilities) net",
        "label": "Assets (liabilities)"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of assets less the amount of liabilities."
       }
      }
     },
     "auth_ref": [
      "r634",
      "r880"
     ]
    },
    "ifrs-full_NetAssetsLiabilitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NetAssetsLiabilitiesAbstract",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets (liabilities)",
        "label": "Net assets (liabilities) [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NetAssetsLiabilitiesAtFairValueThroughProfitOrLossCategoryOtherIncomeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NetAssetsLiabilitiesAtFairValueThroughProfitOrLossCategoryOtherIncomeMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net assets (liabilities) at fair value through profit or loss, category other income",
        "label": "Net Assets (Liabilities) At Fair Value Through Profit Or Loss, Category Other Income [Member]",
        "documentation": "This member stands for the net assets (liabilities) at fair value through profit or loss category, located in other income. [Refer: Financial liabilities at fair value through profit or loss]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NetAssetsLiabilitiesAtFairValueThroughProfitOrLossCategoryTradingIncomeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NetAssetsLiabilitiesAtFairValueThroughProfitOrLossCategoryTradingIncomeMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net assets (liabilities) at fair value through profit or loss, category trading income",
        "label": "Net Assets (Liabilities) At Fair Value Through Profit Or Loss, Category Trading Income [Member]",
        "documentation": "This member stands for the net assets (liabilities) at fair value through profit or loss category, located in trading income. [Refer: Financial liabilities at fair value through profit or loss]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NetAssetsLiabilitiesOrDisposalGroupsClassifiedAsHeldForSale": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NetAssetsLiabilitiesOrDisposalGroupsClassifiedAsHeldForSale",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Net assets classified as held for sale",
        "label": "Net Assets (Liabilities) Or Disposal Groups Classified As Held For Sale",
        "documentation": "Net Assets (Liabilities) Or Disposal Groups Classified As Held For Sale"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_NetDefinedBenefitLiabilityAssetAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NetDefinedBenefitLiabilityAssetAxis",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net defined benefit liability (asset) [axis]",
        "label": "Net defined benefit liability (asset) [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r22",
      "r406"
     ]
    },
    "ifrs-full_NetDefinedBenefitLiabilityAssetDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NetDefinedBenefitLiabilityAssetDomain",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net defined benefit liability (asset) [domain]",
        "label": "Net defined benefit liability (asset) [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the net defined benefit liability (asset). It also represents the standard value for the 'Net defined benefit liability (asset)' axis if no other member is used. [Refer: Net defined benefit liability (asset)]"
       }
      }
     },
     "auth_ref": [
      "r22",
      "r406"
     ]
    },
    "bbplc_NetExposureToCreditRisk": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NetExposureToCreditRisk",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Exposure net of risk mitigation",
        "label": "Net Exposure To Credit Risk",
        "documentation": "The net amount of exposure to credit risk."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails": {
       "parentTag": "bbplc_NetExposureToCreditRisk",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Maximum exposure",
        "totalLabel": "Net amount",
        "label": "Net financial assets subject to offsetting, enforceable master netting arrangements or similar agreements"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount remaining after deducting the amounts subject to an enforceable master netting arrangement or similar agreement that were not set off against financial assets, from the net amount of financial assets subject to offsetting or subject to an enforceable master netting arrangement or similar agreement presented in the statement of financial position."
       }
      }
     },
     "auth_ref": [
      "r242"
     ]
    },
    "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsAbstract",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net financial assets subject to offsetting, enforceable master netting arrangements or similar agreements [abstract]",
        "label": "Net financial assets subject to offsetting, enforceable master netting arrangements or similar agreements [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NetFinancialAssetsSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": "ifrs-full_ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Net amounts reported on the balance sheet",
        "label": "Net financial assets subject to offsetting, enforceable master netting arrangements or similar agreements in statement of financial position"
       }
      },
      "en": {
       "role": {
        "documentation": "The net amount of financial assets that are subject either to offsetting or to an enforceable master netting arrangement or similar agreement, presented in the statement of financial position. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r241"
     ]
    },
    "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreements",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTotalLabel": "Net amount",
        "label": "Net financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount remaining after deducting the amounts subject to an enforceable master netting arrangement or similar agreement that were not set off against financial liabilities, from the net amount of financial liabilities subject to offsetting or subject to an enforceable master netting arrangement or similar agreement presented in the statement of financial position."
       }
      }
     },
     "auth_ref": [
      "r242"
     ]
    },
    "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPosition",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": "ifrs-full_DerivativeFinancialLiabilities",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTotalLabel": "Net amounts reported on the balance sheet",
        "label": "Net financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements in statement of financial position"
       }
      },
      "en": {
       "role": {
        "documentation": "The net amount of financial liabilities that are subject either to offsetting or to an enforceable master netting arrangement or similar agreement, presented in the statement of financial position. [Refer: Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r241"
     ]
    },
    "ifrs-full_NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPositionAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NetFinancialLiabilitiesSubjectToOffsettingEnforceableMasterNettingArrangementsOrSimilarAgreementsInStatementOfFinancialPositionAbstract",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements in statement of financial position [abstract]",
        "label": "Net financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements in statement of financial position [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "us-gaap_NetIncomeLoss": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://fasb.org/us-gaap/2025",
     "localname": "NetIncomeLoss",
     "crdr": "credit",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Net Income (Loss)",
        "terseLabel": "Net Income (Loss)"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NetInvestmentIncomeExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NetInvestmentIncomeExpense",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "bbplc_OperatingIncome",
       "weight": 1.0,
       "order": 4.0
      },
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Net investment (expense)/income",
        "totalLabel": "Net investment (expense)/income",
        "label": "Net Investment Income (Expense)",
        "documentation": "The amount of income or (expense) arising from investments."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NetPensionCostTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NetPensionCostTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Disclosure of income statement charge",
        "label": "Net Pension Cost [Table Text Block]",
        "documentation": "The disclosure of net pension cost."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_NetworkInfrastructureMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NetworkInfrastructureMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Infrastructure",
        "label": "Network infrastructure [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a class of property, plant and equipment representing network infrastructure. [Refer: Property, plant and equipment]"
       }
      }
     },
     "auth_ref": [
      "r838"
     ]
    },
    "ifrs-full_NominalAmountOfHedgingInstrument": {
     "xbrltype": "decimalItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NominalAmountOfHedgingInstrument",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Nominal amount",
        "verboseLabel": "Notional amount",
        "label": "Nominal amount of hedging instrument"
       }
      },
      "en": {
       "role": {
        "documentation": "The nominal amount of a hedging instrument. [Refer: Hedging instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r254",
      "r258",
      "r493"
     ]
    },
    "bbplc_NonAssetBackedLoansMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NonAssetBackedLoansMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans",
        "label": "Non-Asset-Backed Loans [Member]",
        "documentation": "\"This member stands for fixed rate loans, primarily the ESHLA portfolio, which are valued using models that discount expected future cash flows.\""
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NonCashCollateralReceivedSubjectToEnforceableMasterNettingArrangementsOrSimilarAgreementNotSetOffAgainstFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NonCashCollateralReceivedSubjectToEnforceableMasterNettingArrangementsOrSimilarAgreementNotSetOffAgainstFinancialAssets",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails": {
       "parentTag": "bbplc_NetExposureToCreditRisk",
       "weight": -1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Non-cash collateral",
        "terseLabel": "Non-cash collateral",
        "label": "Non-Cash Collateral Received Subject To Enforceable Master Netting Arrangements Or Similar Agreement Not Set Off Against Financial Assets",
        "documentation": "The amount of non-cash collateral received that is subject to an enforceable master netting arrangement or similar agreement and that is not set off against financial assets. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSalePercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NonCurrentAssetsOrDisposalGroupsClassifiedAsHeldForSalePercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets held for sale, percentage",
        "label": "Non-Current Assets or Disposal Groups Classified as Held For Sale, Percentage",
        "documentation": "Non-Current Assets or Disposal Groups Classified as Held For Sale, Percentage"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_NonGaapMeasureDescriptionTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "NonGaapMeasureDescriptionTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Non-GAAP Measure Description [Text Block]",
        "terseLabel": "Non-GAAP Measure Description"
       }
      }
     },
     "auth_ref": [
      "r784"
     ]
    },
    "ecd_NonNeosMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "NonNeosMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Non-NEOs [Member]",
        "terseLabel": "Non-NEOs"
       }
      }
     },
     "auth_ref": [
      "r747",
      "r758",
      "r768",
      "r792",
      "r801"
     ]
    },
    "ecd_NonPeoNeoAvgCompActuallyPaidAmt": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "NonPeoNeoAvgCompActuallyPaidAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Non-PEO NEO Average Compensation Actually Paid Amount",
        "terseLabel": "Non-PEO NEO Average Compensation Actually Paid Amount"
       }
      }
     },
     "auth_ref": [
      "r775"
     ]
    },
    "ecd_NonPeoNeoAvgTotalCompAmt": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "NonPeoNeoAvgTotalCompAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Non-PEO NEO Average Total Compensation Amount",
        "terseLabel": "Non-PEO NEO Average Total Compensation Amount"
       }
      }
     },
     "auth_ref": [
      "r774"
     ]
    },
    "ecd_NonPeoNeoMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "NonPeoNeoMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Non-PEO NEO [Member]",
        "terseLabel": "Non-PEO NEO"
       }
      }
     },
     "auth_ref": [
      "r792"
     ]
    },
    "bbplc_NonRecurringItemsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NonRecurringItemsAbstract",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-recurring items:",
        "label": "Non-Recurring Items [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NonRecurringItemsPercentagesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NonRecurringItemsPercentagesAbstract",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-recurring items, percentages",
        "label": "Non-Recurring Items, Percentages [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_NonRule10b51ArrAdoptedFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "NonRule10b51ArrAdoptedFlag",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Non-Rule 10b5-1 Arrangement Adopted [Flag]",
        "terseLabel": "Non-Rule 10b5-1 Arrangement Adopted"
       }
      }
     },
     "auth_ref": [
      "r812"
     ]
    },
    "ecd_NonRule10b51ArrTrmntdFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "NonRule10b51ArrTrmntdFlag",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Non-Rule 10b5-1 Arrangement Terminated [Flag]",
        "terseLabel": "Non-Rule 10b5-1 Arrangement Terminated"
       }
      }
     },
     "auth_ref": [
      "r812"
     ]
    },
    "ifrs-full_NoncashAssetsPledgedAsCollateralForWhichTransfereeHasRightByContractOrCustomToSellOrRepledgeCollateral": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NoncashAssetsPledgedAsCollateralForWhichTransfereeHasRightByContractOrCustomToSellOrRepledgeCollateral",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-cash collateral pledged",
        "label": "Non-cash assets pledged as collateral for which transferee has right by contract or custom to sell or repledge collateral"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of non-cash collateral assets (such as debt or equity instruments) provided to a transferee, for which the transferee has the right by contract or custom to sell or repledge the collateral."
       }
      }
     },
     "auth_ref": [
      "r347"
     ]
    },
    "ifrs-full_NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSale": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSale",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails": {
       "parentTag": "bbplc_NetAssetsLiabilitiesOrDisposalGroupsClassifiedAsHeldForSale",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialAssets",
       "weight": 1.0,
       "order": 8.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 11.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 18.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails",
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets included in disposal group classified as held for sale",
        "verboseLabel": "Assets held for sale",
        "totalLabel": "Total assets classified as held for sale",
        "label": "Non-current assets or disposal groups classified as held for sale"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of non-current assets or disposal groups classified as held for sale. [Refer: Disposal groups classified as held for sale [member]]"
       }
      }
     },
     "auth_ref": [
      "r234"
     ]
    },
    "ifrs-full_NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets held for sale",
        "label": "Non-current assets or disposal groups classified as held for sale [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for non-current assets or disposal groups classified as held for sale. [Refer: Disposal groups classified as held for sale [member]; Non-current assets held for sale [member]]"
       }
      }
     },
     "auth_ref": [
      "r852"
     ]
    },
    "ifrs-full_NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleOrAsHeldForDistributionToOwnersAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleOrAsHeldForDistributionToOwnersAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-current assets or disposal groups classified as held for sale or as held for distribution to owners [abstract]",
        "label": "Non-current assets or disposal groups classified as held for sale or as held for distribution to owners [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_NotInternallyGeneratedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NotInternallyGeneratedMember",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other",
        "label": "Not internally generated [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for items that have not been internally generated by the entity."
       }
      }
     },
     "auth_ref": [
      "r104",
      "r453"
     ]
    },
    "ifrs-full_NotLaterThanOneMonthMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NotLaterThanOneMonthMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Not more than one month",
        "label": "Not later than one month [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of not later than one month."
       }
      }
     },
     "auth_ref": [
      "r672",
      "r677",
      "r689"
     ]
    },
    "ifrs-full_NotLaterThanOneYearMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NotLaterThanOneYearMember",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofmaturityanalysisofleaseliabilitiesDetails",
      "http://www.home.barclays/role/ProvisionsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Not more than one year",
        "label": "Not later than one year [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of not later than one year."
       }
      }
     },
     "auth_ref": [
      "r196",
      "r197",
      "r210",
      "r369",
      "r372",
      "r577",
      "r674",
      "r689"
     ]
    },
    "bbplc_NotLaterThanTenYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NotLaterThanTenYearsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Within 10 years",
        "label": "Not Later Than Ten Years [Member]",
        "documentation": "This member stands for a time band of not later than ten years."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_NotLaterThanThreeMonthsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NotLaterThanThreeMonthsMember",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Not later than three months",
        "label": "Not later than three months [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a time band of not later than three months."
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "ifrs-full_NotMeasuredAtFairValueInStatementOfFinancialPositionButForWhichFairValueIsDisclosedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NotMeasuredAtFairValueInStatementOfFinancialPositionButForWhichFairValueIsDisclosedMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Not held at fair value",
        "label": "Not measured at fair value in statement of financial position but for which fair value is disclosed [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for items not measured at fair value in the statement of financial position but for which fair value is disclosed. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r174"
     ]
    },
    "ifrs-full_NotionalAmount": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NotionalAmount",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureoftotalderivativesDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Notional contract amount",
        "label": "Notional amount"
       }
      },
      "en": {
       "role": {
        "documentation": "The nominal or face amount of a financial instrument, used to calculate payments made on that instrument."
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "bbplc_NumberOfArbitrationRequestsReceived": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfArbitrationRequestsReceived",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of arbitration requests received",
        "label": "Number Of Arbitration Requests Received",
        "documentation": "Number Of Arbitration Requests Received"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfClaimsPendingResolution": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfClaimsPendingResolution",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of claims pending resolution",
        "label": "Number Of Claims Pending Resolution",
        "documentation": "Number of claims pending resolution"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfConvertibleInstrumentsIssued": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfConvertibleInstrumentsIssued",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of convertible instruments issued",
        "label": "Number Of Convertible Instruments Issued",
        "documentation": "The number of convertible instruments issued during the period."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfConvertibleInstrumentsRedeemed": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfConvertibleInstrumentsRedeemed",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of convertible instruments redeemed",
        "label": "Number Of Convertible Instruments Redeemed",
        "documentation": "The number of convertible instruments redeemed during the period."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfDirectorsOnTrusteeBoard": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfDirectorsOnTrusteeBoard",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of directors on trustee board",
        "label": "Number Of Directors On Trustee Board",
        "documentation": "Number Of Directors On Trustee Board"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_NumberOfEmployees": {
     "xbrltype": "decimalItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NumberOfEmployees",
     "presentation": [
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of employees (full time equivalent)",
        "label": "Number of employees"
       }
      },
      "en": {
       "role": {
        "documentation": "The number of personnel employed by the entity at a date."
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "bbplc_NumberOfFinalDecisionsByTheUKFinancialOmbudsmanService": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfFinalDecisionsByTheUKFinancialOmbudsmanService",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of final decisions by the UK FCO",
        "label": "Number Of Final Decisions By The UK Financial Ombudsman Service",
        "documentation": "Number Of Final Decisions By The UK Financial Ombudsman Service"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfHedges": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfHedges",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of hedges",
        "label": "Number Of Hedges",
        "documentation": "The number of hedges for which the average rate is applied."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfInitialLawsuitsAmended": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfInitialLawsuitsAmended",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of initial lawsuit amended",
        "label": "Number Of Initial Lawsuits Amended",
        "documentation": "Number Of Initial Lawsuit Amended"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfInitialLawsuitsCurrentlyStayed": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfInitialLawsuitsCurrentlyStayed",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of initial lawsuits currently stayed",
        "label": "Number Of Initial Lawsuits Currently Stayed",
        "documentation": "Number Of Initial Lawsuits Currently Stayed"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfInterimDividendsPaid": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfInterimDividendsPaid",
     "presentation": [
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of interim dividends paid",
        "label": "Number Of Interim Dividends Paid",
        "documentation": "Number Of Interim Dividends Paid"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfLawsuitsConsolidatedIntoASeparateLawsuit": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfLawsuitsConsolidatedIntoASeparateLawsuit",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of lawsuits consolidated into a separate lawsuit",
        "label": "Number Of Lawsuits Consolidated Into A Separate Lawsuit",
        "documentation": "Number Of Lawsuits Consolidated Into A Separate Lawsuit"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfLawsuitsDismissed": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfLawsuitsDismissed",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of lawsuits dismissed",
        "label": "Number Of Lawsuits Dismissed",
        "documentation": "Number Of Lawsuits Dismissed"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfLawsuitsSubjectToAppeal": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfLawsuitsSubjectToAppeal",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of lawsuits subject to appeal",
        "label": "Number Of Lawsuits Subject To Appeal",
        "documentation": "Number Of Lawsuits Subject To Appeal"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfLawsuitsWithSpecifiedDamagesSought": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfLawsuitsWithSpecifiedDamagesSought",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of lawsuits with specified damages sought",
        "label": "Number Of Lawsuits With Specified Damages Sought",
        "documentation": "The number of lawsuits with damages sought specified."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfLeases": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfLeases",
     "presentation": [
      "http://www.home.barclays/role/LeasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of leases",
        "label": "Number Of Leases",
        "documentation": "The number of leases held by the entity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfLeasesWithVariableLeasePaymentTerms": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfLeasesWithVariableLeasePaymentTerms",
     "presentation": [
      "http://www.home.barclays/role/LeasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of leases with variable lease payment terms",
        "label": "Number Of Leases With Variable Lease Payment Terms",
        "documentation": "The number of leases with variable lease payment terms based on market based pricing adjustments."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfLongevityReinsuranceContracts": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfLongevityReinsuranceContracts",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of longevity reinsurance contracts",
        "label": "Number Of Longevity Reinsurance Contracts",
        "documentation": "Number Of Longevity Reinsurance Contracts"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_NumberOfOutstandingShareOptions": {
     "xbrltype": "decimalItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NumberOfOutstandingShareOptions",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of options/awards outstanding (in shares)",
        "periodStartLabel": "Outstanding at beginning of year/acquisition date (in shares)",
        "periodEndLabel": "Outstanding at end of year (in shares)",
        "label": "Number of share options outstanding in share-based payment arrangement"
       }
      },
      "en": {
       "role": {
        "documentation": "The number of share options outstanding in a share-based payment arrangement."
       }
      }
     },
     "auth_ref": [
      "r213",
      "r218",
      "r222",
      "r461",
      "r466"
     ]
    },
    "bbplc_NumberOfPlaintiffs": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfPlaintiffs",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of plaintiffs",
        "label": "Number Of Plaintiffs",
        "documentation": "Number Of Plaintiffs"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_NumberOfSeparateLawsuits": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfSeparateLawsuits",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of separate lawsuit",
        "label": "Number Of Separate Lawsuits",
        "documentation": "Number Of Separate Lawsuits"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_NumberOfShareOptionsExercisableInSharebasedPaymentArrangement": {
     "xbrltype": "decimalItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NumberOfShareOptionsExercisableInSharebasedPaymentArrangement",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails",
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of options exercisable (in shares)",
        "label": "Number of share options exercisable in share-based payment arrangement"
       }
      },
      "en": {
       "role": {
        "documentation": "The number of share options exercisable in a share-based payment arrangement."
       }
      }
     },
     "auth_ref": [
      "r219",
      "r467"
     ]
    },
    "ifrs-full_NumberOfShareOptionsExercisedInSharebasedPaymentArrangement": {
     "xbrltype": "decimalItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NumberOfShareOptionsExercisedInSharebasedPaymentArrangement",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Exercised/released in the year (in shares)",
        "label": "Number of share options exercised in share-based payment arrangement"
       }
      },
      "en": {
       "role": {
        "documentation": "The number of share options exercised in a share-based payment arrangement."
       }
      }
     },
     "auth_ref": [
      "r216",
      "r464"
     ]
    },
    "ifrs-full_NumberOfShareOptionsExpiredInSharebasedPaymentArrangement": {
     "xbrltype": "decimalItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NumberOfShareOptionsExpiredInSharebasedPaymentArrangement",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Less: expired in the year (in shares)",
        "label": "Number of share options expired in share-based payment arrangement"
       }
      },
      "en": {
       "role": {
        "documentation": "The number of share options expired in a share-based payment arrangement."
       }
      }
     },
     "auth_ref": [
      "r217",
      "r465"
     ]
    },
    "ifrs-full_NumberOfShareOptionsForfeitedInSharebasedPaymentArrangement": {
     "xbrltype": "decimalItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NumberOfShareOptionsForfeitedInSharebasedPaymentArrangement",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Less: forfeited in the year (in shares)",
        "label": "Number of share options forfeited in share-based payment arrangement"
       }
      },
      "en": {
       "role": {
        "documentation": "The number of share options forfeited in a share-based payment arrangement."
       }
      }
     },
     "auth_ref": [
      "r215",
      "r463"
     ]
    },
    "ifrs-full_NumberOfShareOptionsGrantedInSharebasedPaymentArrangement": {
     "xbrltype": "decimalItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NumberOfShareOptionsGrantedInSharebasedPaymentArrangement",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Granted in the year (in shares)",
        "label": "Number of share options granted in share-based payment arrangement"
       }
      },
      "en": {
       "role": {
        "documentation": "The number of share options granted in a share-based payment arrangement."
       }
      }
     },
     "auth_ref": [
      "r214",
      "r462"
     ]
    },
    "bbplc_NumberOfShareOptionsTransferredInShareBasedPaymentArrangementShares": {
     "xbrltype": "sharesItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfShareOptionsTransferredInShareBasedPaymentArrangementShares",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Transfers within the year (in shares)",
        "label": "Number Of Share Options Transferred In Share-Based Payment Arrangement, Shares",
        "documentation": "The number of share options transferred in a share-based payment arrangement."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_NumberOfSharesIssuedAndFullyPaid": {
     "xbrltype": "sharesItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "NumberOfSharesIssuedAndFullyPaid",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of shares issued and fully paid (in shares)",
        "label": "Number of shares issued and fully paid"
       }
      },
      "en": {
       "role": {
        "documentation": "The number of shares issued by the entity, for which full payment has been received."
       }
      }
     },
     "auth_ref": [
      "r378",
      "r535",
      "r582"
     ]
    },
    "bbplc_NumberOfStructuredEntities": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "NumberOfStructuredEntities",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of structured entities",
        "label": "Number Of Structured Entities",
        "documentation": "Number Of Structured Entities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OTCDerivativesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OTCDerivativesMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "OTC derivatives",
        "label": "OTC Derivatives [Member]",
        "documentation": "This member stands for over the counter traded derivatives."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OffBalanceSheetLoanCommitmentsAndFinancialGuaranteeContractsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OffBalanceSheetLoanCommitmentsAndFinancialGuaranteeContractsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Off-balance sheet",
        "netLabel": "Loan commitments and financial guarantees",
        "label": "Off-Balance Sheet Loan Commitments And Financial Guarantee Contracts [Member]",
        "documentation": "This member stands for off balance sheet loan commitments and financial guarantee contracts."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OffBalanceSheetNotionalAmountsOfAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OffBalanceSheetNotionalAmountsOfAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails": {
       "parentTag": "ifrs-full_MaximumExposureToLossFromInterestsInStructuredEntities",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total off-balance sheet notional amounts",
        "label": "Off-Balance Sheet Notional Amounts Of Assets",
        "documentation": "Total notional amounts of assets that do not appear on the balance sheet the entity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OffsettingFinancialAssetsAndFinancialLiabilitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OffsettingFinancialAssetsAndFinancialLiabilitiesAbstract",
     "lang": {
      "en-us": {
       "role": {
        "label": "Offsetting Financial Assets And Financial Liabilities [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OnBalanceSheetAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OnBalanceSheetAbstract",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "On-balance sheet, values",
        "label": "On-Balance Sheet [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OnBalanceSheetAssetsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OnBalanceSheetAssetsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "On-balance sheet",
        "label": "On-Balance Sheet Assets [Member]",
        "documentation": "This member stands for the on-balance sheet assets of the entity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OnBalanceSheetPercentageAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OnBalanceSheetPercentageAbstract",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "On-balance sheet, percentage",
        "label": "On-Balance Sheet, Percentage [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OnDemandMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OnDemandMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Callable",
        "label": "On demand [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for an on demand time band."
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "ifrs-full_OneYearBeforeReportingYearMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OneYearBeforeReportingYearMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "One year before reporting year",
        "label": "One year before reporting year [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a year that ended one year before the end of the reporting year."
       }
      }
     },
     "auth_ref": [
      "r209"
     ]
    },
    "ifrs-full_OnerousContractsProvisionMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OnerousContractsProvisionMember",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Onerous contracts",
        "label": "Onerous contracts provision [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a provision for onerous contracts. [Refer: Onerous contracts provision]"
       }
      }
     },
     "auth_ref": [
      "r622"
     ]
    },
    "ifrs-full_OperatingExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OperatingExpense",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "bbplc_ProfitLossFromOperatingActivitiesBeforeImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
       "weight": -1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement": {
       "parentTag": "bbplc_ProfitLossFromOperatingActivitiesBeforeImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
       "weight": -1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofamountsincludedintheGroupsfinancialstatementsbycategoryDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTotalLabel": "Operating expenses",
        "negatedLabel": "Operating expenses",
        "label": "Operating expense"
       }
      }
     },
     "auth_ref": [
      "r887"
     ]
    },
    "bbplc_OperatingExpensesExcludingRegulatoryLeviesLitigationAndConduct": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OperatingExpensesExcludingRegulatoryLeviesLitigationAndConduct",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails": {
       "parentTag": "ifrs-full_OperatingExpense",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Operating costs",
        "label": "Operating Expenses Excluding Regulatory Levies, Litigation And Conduct",
        "documentation": "Operating Expenses Excluding Regulatory Levies, Litigation And Conduct"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OperatingIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OperatingIncome",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "bbplc_ProfitLossFromOperatingActivitiesBeforeImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement": {
       "parentTag": "bbplc_ProfitLossFromOperatingActivitiesBeforeImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofamountsincludedintheGroupsfinancialstatementsbycategoryDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total income",
        "terseLabel": "Operating Income",
        "label": "Operating Income",
        "documentation": "Operating Income"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OperatingSegmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OperatingSegmentsMember",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Operating segments",
        "label": "Operating segments [member]"
       }
      }
     },
     "auth_ref": [
      "r341"
     ]
    },
    "ifrs-full_OptionPricingModelMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OptionPricingModelMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Option model",
        "label": "Option pricing model [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a specific valuation technique consistent with the income approach that involves analysing future amounts with option pricing models, such as the Black-Scholes-Merton formula or a binominal model (ie a lattice model), that incorporate present value techniques and reflect both the time value and intrinsic value of an option. [Refer: Income approach [member]]"
       }
      }
     },
     "auth_ref": [
      "r642",
      "r651"
     ]
    },
    "ifrs-full_OrdinarySharesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OrdinarySharesMember",
     "presentation": [
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Ordinary share capital",
        "label": "Ordinary shares [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for equity instruments that are subordinate to all other classes of equity instruments."
       }
      }
     },
     "auth_ref": [
      "r886"
     ]
    },
    "bbplc_OriginatedAndSoldToThirdPartiesByAcquiredSubsidiaryMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OriginatedAndSoldToThirdPartiesByAcquiredSubsidiaryMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Originated and sold to third parties by acquired subsidiary",
        "label": "Originated And Sold To Third Parties By Acquired Subsidiary [Member]",
        "documentation": "This member stands for sales of loans originated and sold to third parties by mortgage originator affiliates of an entity that the Group acquired in 2007 (Acquired Subsidiary)."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherAdjustmentsForNoncashItems": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherAdjustmentsForNoncashItems",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 6.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other non-cash movements including exchange rate movements",
        "label": "Other adjustments for non-cash items"
       }
      }
     },
     "auth_ref": [
      "r866"
     ]
    },
    "bbplc_OtherAdjustmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherAdjustmentsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other adjustments",
        "label": "Other Adjustments [Member]",
        "documentation": "ECL correction made to models appearing overly sensitive to the Federal Tax Receipts variable, in addition to a number of updates informed by business as usual model monitoring."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails": {
       "parentTag": "ifrs-full_NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSale",
       "weight": 1.0,
       "order": 4.0
      },
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 8.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 19.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails",
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other assets",
        "label": "Other assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of assets that the entity does not separately disclose in the same statement or note."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_OtherAssetsAmountContributedToFairValueOfPlanAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherAssetsAmountContributedToFairValueOfPlanAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails": {
       "parentTag": "ifrs-full_PlanAssetsAtFairValue",
       "weight": 1.0,
       "order": 10.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other",
        "label": "Other assets, amount contributed to fair value of plan assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount other types of assets not separately disclosed contribute to the fair value of defined benefit plan assets. [Refer: Plan assets, at fair value; Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r413",
      "r845"
     ]
    },
    "bbplc_OtherAssetsIncludingAmountsHeldForSale": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherAssetsIncludingAmountsHeldForSale",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other assets",
        "label": "Other Assets, Including Amounts Held For Sale",
        "documentation": "The amount of of assets that the entity does not separately disclose in the same statement or note including, non-current assets or disposal groups classified as held for sale or as held for distribution to owners. [Refer: Non-current assets or disposal groups classified as held for distribution to owners; Non-current assets or disposal groups classified as held for sale]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherAssetsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherAssetsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other assets",
        "label": "Other assets [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for assets that the entity does not separately disclose in the same statement or note."
       }
      }
     },
     "auth_ref": [
      "r654",
      "r699"
     ]
    },
    "bbplc_OtherAuditRelatedFeesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherAuditRelatedFeesMember",
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails",
      "http://www.home.barclays/role/AuditorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other audit related fees",
        "label": "Other Audit Related Fees [Member]",
        "documentation": "This member stands for other audit related fees."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherAuditorServicesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherAuditorServicesMember",
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other services",
        "label": "Other Auditor Services [Member]",
        "documentation": "This member stands for other auditor services."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherComprehensiveIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherComprehensiveIncome",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_ComprehensiveIncome",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_GainsLossesRecognisedInProfitOrLossAttributableToChangeInUnrealisedGainsOrLossesForAssetsHeldAtEndOfPeriodFairValueMeasurement",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Other comprehensive income/(loss) for the year",
        "terseLabel": "Other comprehensive income",
        "label": "Other comprehensive income"
       }
      }
     },
     "auth_ref": [
      "r148",
      "r552",
      "r588",
      "r598"
     ]
    },
    "ifrs-full_OtherComprehensiveIncomeBeforeTaxChangeInFairValueOfFinancialLiabilityAttributableToChangeInCreditRiskOfLiability": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherComprehensiveIncomeBeforeTaxChangeInFairValueOfFinancialLiabilityAttributableToChangeInCreditRiskOfLiability",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Own credit",
        "label": "Other comprehensive income, before tax, change in fair value of financial liability attributable to change in credit risk of liability"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of other comprehensive income, before tax, related to change in the fair value of financial liability attributable to change in the credit risk of the liability. [Refer: Other comprehensive income, before tax; Credit risk [member]]"
       }
      }
     },
     "auth_ref": [
      "r580",
      "r599"
     ]
    },
    "ifrs-full_OtherComprehensiveIncomeBeforeTaxExchangeDifferencesOnTranslation": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherComprehensiveIncomeBeforeTaxExchangeDifferencesOnTranslation",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Currency translation differences",
        "label": "Other comprehensive income, before tax, exchange differences on translation of foreign operations"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of other comprehensive income, before tax, after reclassification adjustments, related to exchange differences on translation of financial statements of foreign operations. [Refer: Other comprehensive income, before tax]"
       }
      }
     },
     "auth_ref": [
      "r580",
      "r599"
     ]
    },
    "ifrs-full_OtherComprehensiveIncomeBeforeTaxGainsLossesFromInvestmentsInEquityInstruments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherComprehensiveIncomeBeforeTaxGainsLossesFromInvestmentsInEquityInstruments",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "auth_ref": [
      "r248",
      "r486",
      "r580",
      "r599"
     ]
    },
    "ifrs-full_OtherComprehensiveIncomeBeforeTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherComprehensiveIncomeBeforeTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Retirement benefit remeasurements",
        "label": "Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of other comprehensive income, before tax, related to gains (losses) on remeasurements of defined benefit plans, which comprise actuarial gains and losses; the return on plan assets, excluding amounts included in net interest on the net defined benefit liability (asset); and any change in the effect of the asset ceiling, excluding amounts included in net interest on the net defined benefit liability (asset). [Refer: Other comprehensive income; Defined benefit plans [domain]; Plan assets [member]; Net defined benefit liability (asset)] [Contrast: Decrease (increase) in net defined benefit liability (asset) resulting from gain (loss) on remeasurement in other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r580",
      "r599",
      "r841"
     ]
    },
    "ifrs-full_OtherComprehensiveIncomeNetOfTaxCashFlowHedges": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherComprehensiveIncomeNetOfTaxCashFlowHedges",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity": {
       "parentTag": "ifrs-full_ComprehensiveIncome",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash flow hedges",
        "label": "Other comprehensive income, net of tax, cash flow hedges"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of other comprehensive income, net of tax, after reclassification adjustments, related to cash flow hedges. [Refer: Cash flow hedges [member]; Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r580",
      "r598"
     ]
    },
    "ifrs-full_OtherComprehensiveIncomeNetOfTaxChangeInFairValueOfFinancialLiabilityAttributableToChangeInCreditRiskOfLiability": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherComprehensiveIncomeNetOfTaxChangeInFairValueOfFinancialLiabilityAttributableToChangeInCreditRiskOfLiability",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity": {
       "parentTag": "ifrs-full_ComprehensiveIncome",
       "weight": 1.0,
       "order": 6.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Own credit reserve",
        "label": "Other comprehensive income, net of tax, change in fair value of financial liability attributable to change in credit risk of liability"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of other comprehensive income, net of tax, related to changes in the fair value of financial liabilities attributable to the changes in the credit risk of those liabilities. [Refer: Other comprehensive income; Credit risk [member]; Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r580",
      "r598"
     ]
    },
    "ifrs-full_OtherComprehensiveIncomeNetOfTaxExchangeDifferencesOnTranslation": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherComprehensiveIncomeNetOfTaxExchangeDifferencesOnTranslation",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity": {
       "parentTag": "ifrs-full_ComprehensiveIncome",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Currency translation movements",
        "verboseLabel": "Currency translation differences",
        "label": "Other comprehensive income, net of tax, exchange differences on translation of foreign operations"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of other comprehensive income, net of tax, after reclassification adjustments, related to exchange differences when financial statements of foreign operations are translated. [Refer: Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r580",
      "r598"
     ]
    },
    "ifrs-full_OtherComprehensiveIncomeNetOfTaxFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherComprehensiveIncomeNetOfTaxFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncome",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity": {
       "parentTag": "ifrs-full_ComprehensiveIncome",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fair value through other comprehensive income reserve",
        "label": "Other comprehensive income, net of tax, financial assets measured at fair value through other comprehensive income"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of other comprehensive income, net of tax, after reclassification adjustments, related to financial assets measured at fair value through other comprehensive income applying paragraph 4.1.2A of IFRS 9. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r580",
      "r598"
     ]
    },
    "ifrs-full_OtherComprehensiveIncomeNetOfTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherComprehensiveIncomeNetOfTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity": {
       "parentTag": "ifrs-full_ComprehensiveIncome",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Retirement benefit remeasurement",
        "verboseLabel": "Retirement benefit remeasurement",
        "label": "Other comprehensive income, net of tax, gains (losses) on remeasurements of defined benefit plans"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of other comprehensive income, net of tax, related to gains (losses) on remeasurements of defined benefit plans, which comprise actuarial gains and losses; the return on plan assets, excluding amounts included in net interest on the net defined benefit liability (asset); and any change in the effect of the asset ceiling, excluding amounts included in net interest on the net defined benefit liability (asset). [Refer: Other comprehensive income; Defined benefit plans [domain]; Plan assets [member]; Net defined benefit liability (asset)] [Contrast: Decrease (increase) in net defined benefit liability (asset) resulting from gain (loss) on remeasurement in other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r580",
      "r598",
      "r841"
     ]
    },
    "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncome",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Other comprehensive income/(loss) that may be recycled to profit or loss",
        "label": "Other comprehensive income that will be reclassified to profit or loss, net of tax"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of other comprehensive income that will be reclassified to profit or loss, net of tax. [Refer: Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r720",
      "r721"
     ]
    },
    "ifrs-full_OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncome",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Other comprehensive income/(loss) not recycled to profit or loss",
        "label": "Other comprehensive income that will not be reclassified to profit or loss, net of tax"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of other comprehensive income that will not be reclassified to profit or loss, net of tax. [Refer: Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r720",
      "r721"
     ]
    },
    "srt_OtherCurrencyMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "OtherCurrencyMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "netLabel": "Other",
        "terseLabel": "Other currencies",
        "verboseLabel": "Other foreign operations",
        "label": "Other Currency [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherEmployeeExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherEmployeeExpense",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/StaffcostsDetails": {
       "parentTag": "bbplc_StaffCompensationCosts",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other compensation costs",
        "label": "Other employee expense"
       }
      }
     },
     "auth_ref": [
      "r848"
     ]
    },
    "ifrs-full_OtherEquityInterest": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherEquityInterest",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Equity",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other equity instruments",
        "verboseLabel": "Total AT1 equity instruments",
        "label": "Other equity interest"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of equity interest of an entity without share capital that the entity does not separately disclose in the same statement or note."
       }
      }
     },
     "auth_ref": [
      "r714",
      "r719"
     ]
    },
    "ifrs-full_OtherEquityInterestMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherEquityInterestMember",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other equity instruments",
        "label": "Other equity interest [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for equity interest of an entity without share capital that the entity does not separately disclose in the same statement or note."
       }
      }
     },
     "auth_ref": [
      "r555"
     ]
    },
    "ifrs-full_OtherFeeAndCommissionIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherFeeAndCommissionIncome",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails": {
       "parentTag": "ifrs-full_FeeAndCommissionIncome",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other non-contract fee income",
        "label": "Other fee and commission income"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "bbplc_OtherFeesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherFeesMember",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other",
        "label": "Other Fees [Member]",
        "documentation": "This member stands for fees in scope of IFRS 15 not specifically covered by the above categories"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherFinancialAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialAssets",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails": {
       "parentTag": "ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLoss",
       "weight": 1.0,
       "order": 5.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 10.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Other assets",
        "terseLabel": "Other financial assets",
        "label": "Other financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial assets that the entity does not separately disclose in the same statement or note. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r567"
     ]
    },
    "bbplc_OtherFinancialAssetsAndLiabilitiesGroupOneMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherFinancialAssetsAndLiabilitiesGroupOneMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other products",
        "label": "Other Financial Assets And Liabilities Group One [Member]",
        "documentation": "This member stands for commercial real estate loans, asset backed loans, funds and fund-linked products, issued debt, government sponsored debt and investment property."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherFinancialAssetsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherFinancialAssetsMember",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails",
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureoftransferredfinancialassetsandtheassociatedliabilitiesDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Other financial assets",
        "terseLabel": "Other financial assets measured at amortised cost",
        "netLabel": "Other",
        "label": "Other, Financial Assets [Member]",
        "documentation": "This member stands a class of financial assets that are categorised as other."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherFinancialAssetsPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherFinancialAssetsPercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other assets, percentage",
        "label": "Other Financial Assets, Percentage",
        "documentation": "The amount of financial assets that the entity does not separately disclose in the same statement or note, expressed as a percentage."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherFinancialAssetsSubjectToImpairmentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherFinancialAssetsSubjectToImpairmentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other financial assets subject to impairment",
        "verboseLabel": "Other financial assets",
        "label": "Other Financial Assets Subject To Impairment [Member]",
        "documentation": "This member stands for other financial assets subject to impairment, which includes cash collateral and settlement balances, financial assets at fair value through other comprehensive income, accrued income and sundry debtors."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherFinancialInstitutionsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherFinancialInstitutionsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other Financial Institutions",
        "label": "Other Financial Institutions [Member]",
        "documentation": "This member stands for other financial institutions."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherFinancialInstrumentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherFinancialInstrumentsMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other products",
        "label": "Other Financial Instruments [Member]",
        "documentation": "Other Financial Instruments"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherFinancialLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherFinancialLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialLiabilities",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other financial liabilities",
        "label": "Other financial liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of financial liabilities that the entity does not separately disclose in the same statement or note. [Refer: Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r571"
     ]
    },
    "bbplc_OtherFinancialLiabilitiesUndiscountedCashFlows": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherFinancialLiabilitiesUndiscountedCashFlows",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails": {
       "parentTag": "bbplc_TotalFinancialLiabilitiesUndiscounted",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other financial liabilities, undiscounted",
        "label": "Other Financial Liabilities, Undiscounted Cash Flows",
        "documentation": "The amount of contractual undiscounted cash flows in relation to other financial liabilities."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherGainsLosses": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherGainsLosses",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Other net (expenses) income",
        "label": "Other gains (losses)"
       }
      }
     },
     "auth_ref": [
      "r877",
      "r878"
     ]
    },
    "bbplc_OtherIncome1Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherIncome1Member",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Recycled to other income",
        "label": "Other Income1 [Member]",
        "documentation": "This member stands for the amount of operating income that the entity does not separately disclose in the same statement or note."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherIncomeExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherIncomeExpense",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails": {
       "parentTag": "bbplc_OperatingIncome",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-interest income",
        "label": "Other Income (Expense)",
        "documentation": "Other Income (Expense)"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherInflowsOutflowsOfCashClassifiedAsInvestingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherInflowsOutflowsOfCashClassifiedAsInvestingActivities",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": 1.0,
       "order": 7.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other cash flows associated with investing activities",
        "label": "Other inflows (outflows) of cash, classified as investing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "Inflows (outflows) of cash, classified as investing activities, that the entity does not separately disclose in the same statement or note."
       }
      }
     },
     "auth_ref": [
      "r118"
     ]
    },
    "bbplc_OtherInterestsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherInterestsMember",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other interests",
        "verboseLabel": "Total",
        "label": "Other Interests [Member]",
        "documentation": "This member stands for other interests."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherInvestmentIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherInvestmentIncome",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails": {
       "parentTag": "bbplc_NetInvestmentIncomeExpense",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Net losses on other investments",
        "label": "Other Investment Income",
        "documentation": "The amount of investment income that the entity does not separately disclose in the same statement or note."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherInvestmentProgramMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherInvestmentProgramMember",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other",
        "label": "Other Investment Program [Member]",
        "documentation": "This member stands for other investment programs."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails": {
       "parentTag": "ifrs-full_LiabilitiesIncludedInDisposalGroupsClassifiedAsHeldForSale",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 15.0
      },
      "http://www.home.barclays/role/OtherliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails",
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/OtherliabilitiesDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other liabilities",
        "totalLabel": "Other liabilities",
        "label": "Other liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of liabilities that the entity does not separately disclose in the same statement or note."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_OtherLiabilitiesIncludingAmountsHeldForSale": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherLiabilitiesIncludingAmountsHeldForSale",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other liabilities",
        "label": "Other Liabilities, Including Amounts Held For Sale",
        "documentation": "The amount of liabilities that the entity does not separately disclose in the same statement or note, including assets including The amount of liabilities included in disposal groups classified as held for sale. [Refer: Liabilities; Disposal groups classified as held for sale [member]]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherLongtermBenefits": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherLongtermBenefits",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/StaffcostsDetails": {
       "parentTag": "bbplc_StaffCompensationCosts",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Performance costs",
        "label": "Other long-term employee benefits"
       }
      }
     },
     "auth_ref": [
      "r847"
     ]
    },
    "bbplc_OtherNonQuotedAssetsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherNonQuotedAssetsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other",
        "label": "Other Non-Quoted Assets [Member]",
        "documentation": "This member stands for other assets held predominantly non-quoted and not separately disclosed."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherOperatingIncomeExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherOperatingIncomeExpense",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_GainsLossesRecognisedInProfitOrLossAttributableToChangeInUnrealisedGainsOrLossesForAssetsHeldAtEndOfPeriodFairValueMeasurement",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "bbplc_OperatingIncome",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/PropertyplantandequipmentNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other income",
        "label": "Other operating income (expense)"
       }
      }
     },
     "auth_ref": [
      "r887"
     ]
    },
    "ifrs-full_OtherPayables": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherPayables",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/OtherliabilitiesDetails": {
       "parentTag": "ifrs-full_OtherLiabilities",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OtherliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Other creditors",
        "label": "Other payables"
       }
      },
      "en": {
       "role": {
        "documentation": "Amounts payable that the entity does not separately disclose in the same statement or note."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_OtherPensionSchemesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherPensionSchemesMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other",
        "label": "Other Pension Schemes [Member]",
        "documentation": "This member stands for a number of smaller pension and long-term employee benefits and post-retirement healthcare plans globally."
       }
      }
     },
     "auth_ref": []
    },
    "ecd_OtherPerfMeasureAmt": {
     "xbrltype": "decimalItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "OtherPerfMeasureAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Other Performance Measure, Amount",
        "terseLabel": "Other Performance Measure, Amount"
       }
      }
     },
     "auth_ref": [
      "r784"
     ]
    },
    "ifrs-full_OtherPriceRiskMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherPriceRiskMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Inflation risk",
        "label": "Other price risk [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a type of market risk representing the risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in market prices (other than those arising from interest rate risk or currency risk), whether those changes are caused by factors specific to the individual financial instrument or its issuer, or by factors affecting all similar financial instruments traded in the market. [Refer: Currency risk [member]; Interest rate risk [member]; Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r203",
      "r204",
      "r205",
      "r207",
      "r328"
     ]
    },
    "bbplc_OtherProceedingsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherProceedingsMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other proceedings",
        "label": "Other Proceedings [Member]",
        "documentation": "Other Proceedings"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherRegionsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherRegionsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Others",
        "label": "Other Regions [Member]",
        "documentation": "Other Regions"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherRelatedPartiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherRelatedPartiesMember",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofamountsincludedintheGroupsfinancialstatementsbycategoryDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fellow subsidiaries",
        "label": "Other related parties [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for related parties that the entity does not separately disclose in the same statement or note. [Refer: Total for all related parties [member]]"
       }
      }
     },
     "auth_ref": [
      "r57",
      "r427"
     ]
    },
    "bbplc_OtherRepaymentsProceedsOfBorrowingsClassifiedAsFinancingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherRepaymentsProceedsOfBorrowingsClassifiedAsFinancingActivities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Other",
        "label": "Other Repayments (Proceeds) Of Borrowings Classified As Financing Activities",
        "documentation": "The cash inflow from and outflow to settle other borrowings, classified as financing activities."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherReserves": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherReserves",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Equity",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/ReservesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other reserves",
        "verboseLabel": "Total",
        "label": "Other reserves"
       }
      },
      "en": {
       "role": {
        "documentation": "A component of equity representing reserves within equity, not including retained earnings. [Refer: Retained earnings]"
       }
      }
     },
     "auth_ref": [
      "r714",
      "r719"
     ]
    },
    "bbplc_OtherReservesAndOtherShareholdersEquityMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherReservesAndOtherShareholdersEquityMember",
     "presentation": [
      "http://www.home.barclays/role/ReservesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other reserves",
        "label": "Other Reserves And Other Shareholders Equity [Member]",
        "documentation": "This member stands for a component of equity representing other reserves within equity and other shareholders equity, not including retained earnings."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherReservesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherReservesMember",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other reserves",
        "label": "Other reserves [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a component of equity representing reserves within equity, not including retained earnings. [Refer: Retained earnings]"
       }
      }
     },
     "auth_ref": [
      "r381",
      "r555"
     ]
    },
    "bbplc_OtherResourcingCosts": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherResourcingCosts",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/StaffcostsDetails": {
       "parentTag": "bbplc_ResourcingCosts",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other",
        "label": "Other Resourcing Costs",
        "documentation": "The amount of costs relating to resourcing, classified as other."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherResourcingCostsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherResourcingCostsAbstract",
     "presentation": [
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other resourcing costs",
        "label": "Other Resourcing Costs [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherRetailMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherRetailMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Retail other",
        "label": "Other, Retail [Member]",
        "documentation": "Other, Retail"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherSchemesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherSchemesMember",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofsharebasedpaymentschemesDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Others",
        "label": "Other Schemes [Member]",
        "documentation": "The member represents other schemes, included are Sharesave (both UK and overseas), Sharepurchase (both UK and overseas), the Barclays' Long Term Incentive Plan, and the Share Incentive Award."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_OtherSubsidiariesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OtherSubsidiariesMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other subsidiaries",
        "verboseLabel": "Other (outside the UK and US tax groups)",
        "label": "Other Subsidiaries [Member]",
        "documentation": "This member stands for other subsidiaries within the group."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_OtherTaxEffectsForReconciliationBetweenAccountingProfitAndTaxExpenseIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherTaxEffectsForReconciliationBetweenAccountingProfitAndTaxExpenseIncome",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 9.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Banking surcharge and other items",
        "label": "Other tax effects for reconciliation between accounting profit and tax expense (income)"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that the entity does not separately disclose in the same statement or note. [Refer: Accounting profit; Applicable tax rate]"
       }
      }
     },
     "auth_ref": [
      "r4",
      "r392"
     ]
    },
    "ifrs-full_OtherTaxRateEffectsForReconciliationBetweenAccountingProfitAndTaxExpenseIncome": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherTaxRateEffectsForReconciliationBetweenAccountingProfitAndTaxExpenseIncome",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": 1.0,
       "order": 9.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Banking surcharge and other items, percentage",
        "label": "Other tax rate effects for reconciliation between accounting profit and tax expense (income)"
       }
      },
      "en": {
       "role": {
        "documentation": "Tax rate effects, in aggregate, on the reconciliation between the average effective tax rate and the applicable tax rate that the entity does not separately disclose in the reconciliation. [Refer: Average effective tax rate; Applicable tax rate]"
       }
      }
     },
     "auth_ref": [
      "r5",
      "r393"
     ]
    },
    "ifrs-full_OtherTemporaryDifferencesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OtherTemporaryDifferencesMember",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other temporary differences",
        "label": "Other temporary differences [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for temporary differences that the entity does not separately disclose in the same statement or note. [Refer: Temporary differences [member]]"
       }
      }
     },
     "auth_ref": [
      "r836"
     ]
    },
    "bbplc_OutsourcingCosts": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OutsourcingCosts",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/StaffcostsDetails": {
       "parentTag": "bbplc_ResourcingCosts",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Outsourcing",
        "label": "Outsourcing Costs",
        "documentation": "The amount of costs relating to outsourcing costs."
       }
      }
     },
     "auth_ref": []
    },
    "ecd_OutstandingAggtErrCompAmt": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "OutstandingAggtErrCompAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Outstanding Aggregate Erroneous Compensation Amount",
        "terseLabel": "Outstanding Aggregate Erroneous Compensation Amount"
       }
      }
     },
     "auth_ref": [
      "r745",
      "r756",
      "r766",
      "r799"
     ]
    },
    "ifrs-full_OutstandingCommitmentsMadeByEntityRelatedPartyTransactions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "OutstandingCommitmentsMadeByEntityRelatedPartyTransactions",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total commitments outstanding",
        "label": "Outstanding commitments made by entity, related party transactions"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of outstanding commitments made by the entity in related party transactions. [Refer: Total for all related parties [member]]"
       }
      }
     },
     "auth_ref": [
      "r50",
      "r421"
     ]
    },
    "ecd_OutstandingRecoveryCompAmt": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "OutstandingRecoveryCompAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Outstanding Recovery Compensation Amount",
        "terseLabel": "Compensation Amount"
       }
      }
     },
     "auth_ref": [
      "r748",
      "r759",
      "r769",
      "r802"
     ]
    },
    "ecd_OutstandingRecoveryIndName": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "OutstandingRecoveryIndName",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Outstanding Recovery, Individual Name",
        "terseLabel": "Name"
       }
      }
     },
     "auth_ref": [
      "r748",
      "r759",
      "r769",
      "r802"
     ]
    },
    "bbplc_OwnCreditMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "OwnCreditMember",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Own credit",
        "label": "Own Credit [Member]",
        "documentation": "Own Credit"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_PRATransitionalRegulatoryCapital": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PRATransitionalRegulatoryCapital",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcapitalresourcesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total regulatory capital",
        "label": "PRA Transitional Regulatory Capital",
        "documentation": "The amount of PRA (a subsidiary of the Bank of England) transitional regulatory capital required of the entity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_PRATransitionalTierOneCapitalMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PRATransitionalTierOneCapitalMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcapitalresourcesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "T1 capital",
        "label": "PRA Transitional Tier One Capital [Member]",
        "documentation": "This member stands for the PRA (a subsidiary of the Bank of England) transitional tier 1 regulatory capital on the entity."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ParValuePerShare": {
     "xbrltype": "perShareItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ParValuePerShare",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Par value (in GBP/ USD per share)",
        "label": "Par value per share"
       }
      },
      "en": {
       "role": {
        "documentation": "The nominal value per share."
       }
      }
     },
     "auth_ref": [
      "r379",
      "r536",
      "r583"
     ]
    },
    "srt_ParentCompanyMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "ParentCompanyMember",
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresDisclosureofinvestmentsinassociatesandjointventuresDetails",
      "http://www.home.barclays/role/LeasesNarrativeDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatementParenthetical",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequityParenthetical",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincomeParenthetical",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/ParentcompanyaccountsbalancesheetParenthetical",
      "http://www.home.barclays/role/ProvisionsNarrativeDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Bank PLC",
        "verboseLabel": "UK Tax Group",
        "label": "Parent Company [Member]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ParentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ParentMember",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofamountsincludedintheGroupsfinancialstatementsbycategoryDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays PLC",
        "verboseLabel": "Parent",
        "label": "Parent [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for an entity that controls one or more entities."
       }
      }
     },
     "auth_ref": [
      "r53",
      "r423"
     ]
    },
    "ifrs-full_PastDueStatusAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PastDueStatusAxis",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Past due status [axis]",
        "label": "Past due status [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r669"
     ]
    },
    "ifrs-full_PastDueStatusDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PastDueStatusDomain",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Past due status [domain]",
        "label": "Past due status [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all past-due statuses. It also represents the standard value for the 'Past due status' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r669"
     ]
    },
    "ecd_PayVsPerformanceDisclosureLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "PayVsPerformanceDisclosureLineItems",
     "lang": {
      "en-us": {
       "role": {
        "label": "Pay vs Performance Disclosure [Line Items]",
        "terseLabel": "Pay vs Performance Disclosure"
       }
      }
     },
     "auth_ref": [
      "r773"
     ]
    },
    "bbplc_PaymentsForVestingOfSharesUnderEmployeeShareSchemes": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PaymentsForVestingOfSharesUnderEmployeeShareSchemes",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities",
       "weight": -1.0,
       "order": 6.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Vesting of employee share schemes",
        "negatedTerseLabel": "Vesting of shares under employee share schemes",
        "label": "Payments For Vesting Of Shares Under Employee Share Schemes",
        "documentation": "The cash outflow for the vesting of shares under employee share schemes."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_PaymentsFromPlanNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PaymentsFromPlanNetDefinedBenefitLiabilityAsset",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Benefits paid",
        "label": "Decrease (increase) in net defined benefit liability (asset) resulting from payments from plan"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease (increase) in the net defined benefit liability (asset) resulting from payments from the plan. [Refer: Net defined benefit liability (asset)]"
       }
      }
     },
     "auth_ref": [
      "r31",
      "r411"
     ]
    },
    "ifrs-full_PaymentsToAcquireOrRedeemEntitysShares": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PaymentsToAcquireOrRedeemEntitysShares",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities",
       "weight": -1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Repurchase of shares and other equity instruments",
        "label": "Payments to acquire or redeem entity's shares"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash outflow to acquire or redeem entity's shares."
       }
      }
     },
     "auth_ref": [
      "r629"
     ]
    },
    "ecd_PeerGroupIssuersFnTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "PeerGroupIssuersFnTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Peer Group Issuers, Footnote [Text Block]",
        "terseLabel": "Peer Group Issuers, Footnote"
       }
      }
     },
     "auth_ref": [
      "r783"
     ]
    },
    "ecd_PeerGroupTotalShareholderRtnAmt": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "PeerGroupTotalShareholderRtnAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Peer Group Total Shareholder Return Amount",
        "terseLabel": "Peer Group Total Shareholder Return Amount"
       }
      }
     },
     "auth_ref": [
      "r783"
     ]
    },
    "ifrs-full_PensionDefinedBenefitPlansMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PensionDefinedBenefitPlansMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Pension defined benefit plans",
        "label": "Pension defined benefit plans [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for pension defined benefit plans. [Refer: Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r842"
     ]
    },
    "bbplc_PensionFundsUnitTrustsAndInvestmentFundsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PensionFundsUnitTrustsAndInvestmentFundsMember",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosureofamountsincludedintheGroupsfinancialstatementsbycategoryDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Pension funds",
        "label": "Pension Funds, Unit Trusts, And Investment Funds [Member]",
        "documentation": "This member stands for pension funds, unit trusts, and investment funds entities."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_PensionersAndDependentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PensionersAndDependentsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Pensioners and Dependents",
        "label": "Pensioners And Dependents [Member]",
        "documentation": "Pensioners And Dependents"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_PeoActuallyPaidCompAmt": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "PeoActuallyPaidCompAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "PEO Actually Paid Compensation Amount",
        "terseLabel": "PEO Actually Paid Compensation Amount"
       }
      }
     },
     "auth_ref": [
      "r775"
     ]
    },
    "ecd_PeoMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "PeoMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "PEO [Member]",
        "terseLabel": "PEO"
       }
      }
     },
     "auth_ref": [
      "r792"
     ]
    },
    "ecd_PeoName": {
     "xbrltype": "normalizedStringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "PeoName",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "PEO Name",
        "terseLabel": "PEO Name"
       }
      }
     },
     "auth_ref": [
      "r785"
     ]
    },
    "ecd_PeoTotalCompAmt": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "PeoTotalCompAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "PEO Total Compensation Amount",
        "terseLabel": "PEO Total Compensation Amount"
       }
      }
     },
     "auth_ref": [
      "r774"
     ]
    },
    "bbplc_PercentageOfBenefitsAreExpectedToBePaid": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PercentageOfBenefitsAreExpectedToBePaid",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Percentage of benefits are expected to be paid",
        "label": "Percentage Of Benefits Are Expected To Be Paid",
        "documentation": "The percentage of benefits are expected to be paid."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_PercentageOfFairValueOfSchemeAssets": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PercentageOfFairValueOfSchemeAssets",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "% of total fair value of scheme assets",
        "label": "Percentage Of Fair Value Of Scheme Assets",
        "documentation": "The percentage of fair value of scheme assets."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_PercentageOfFairValueOfSchemeAssetsInvestedInLiabilities": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PercentageOfFairValueOfSchemeAssetsInvestedInLiabilities",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Percentage of fair value of scheme assets invested in liability driven investment strategies",
        "label": "Percentage Of Fair Value Of Scheme Assets Invested In Liabilities",
        "documentation": "Percentage of fair value of scheme assets invested in liability driven investment strategies."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_PercentageOfFundingDeficitSecuredByCollateralPool": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PercentageOfFundingDeficitSecuredByCollateralPool",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Percentage of funding deficit secured by collateral pool",
        "label": "Percentage Of Funding Deficit Secured By Collateral Pool",
        "documentation": "The percentage of funding deficit by which collateral pool has been put in place to provide security as it increases or decreases over time, and associated deficit recovery contributions."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_PercentageOfIssuedShareCapital": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PercentageOfIssuedShareCapital",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Percentage of issued share capital",
        "label": "Percentage Of Issued Share Capital",
        "documentation": "The amount issued share capital, expressed as a percentage."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_PercentageOfLongevityRiskForCurrentPensionersReinsured": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PercentageOfLongevityRiskForCurrentPensionersReinsured",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Percentage of longevity risk for current pensioners reinsured",
        "label": "Percentage of Longevity Risk for Current Pensioners Reinsured",
        "documentation": "Percentage of Longevity Risk for Current Pensioners Reinsured"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_PercentageOfReasonablyPossibleDecreaseInActuarialAssumption": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PercentageOfReasonablyPossibleDecreaseInActuarialAssumption",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Percentage of reasonably possible decrease in actuarial assumption",
        "label": "Percentage of reasonably possible decrease in actuarial assumption"
       }
      },
      "en": {
       "role": {
        "documentation": "The reasonably possible percentage of the decrease in the actuarial assumption used to determine the present value of defined benefit obligation. [Refer: Actuarial assumptions [domain]]"
       }
      }
     },
     "auth_ref": [
      "r34"
     ]
    },
    "ifrs-full_PercentageOfReasonablyPossibleIncreaseInActuarialAssumption": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PercentageOfReasonablyPossibleIncreaseInActuarialAssumption",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Percentage of reasonably possible increase in actuarial assumption",
        "label": "Percentage of reasonably possible increase in actuarial assumption"
       }
      },
      "en": {
       "role": {
        "documentation": "The reasonably possible percentage of the increase in the actuarial assumption used to determine the present value of defined benefit obligation. [Refer: Actuarial assumptions [domain]]"
       }
      }
     },
     "auth_ref": [
      "r34"
     ]
    },
    "bbplc_PerformanceGuaranteesAcceptancesAndEndorsementsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PerformanceGuaranteesAcceptancesAndEndorsementsMember",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Performance guarantees, acceptances and endorsements",
        "label": "Performance Guarantees, Acceptances And Endorsements [Member]",
        "documentation": "This member stands for performance guarantees, acceptances and endorsements."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_PersonalLoansMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PersonalLoansMember",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Personal Loans",
        "label": "Personal Loans [Member]",
        "documentation": "Personal Loans"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_PlanAssetsAtFairValue": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PlanAssetsAtFairValue",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Fair value of scheme assets",
        "label": "Plan assets, at fair value"
       }
      },
      "en": {
       "role": {
        "documentation": "The fair value of defined benefit plan assets. Plan assets comprise assets held by a long-term employee benefit fund and qualifying insurance policies. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r849"
     ]
    },
    "ifrs-full_PlanAssetsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PlanAssetsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fair value of plan assets",
        "label": "Plan assets [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for defined benefit plan assets. Plan assets comprise: (a) assets held by a long-term employee benefit fund; and (b) qualifying insurance policies."
       }
      }
     },
     "auth_ref": [
      "r20",
      "r404"
     ]
    },
    "ecd_PnsnAdjsPrrSvcCstMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "PnsnAdjsPrrSvcCstMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Pension Adjustments Prior Service Cost [Member]",
        "terseLabel": "Pension Adjustments Prior Service Cost"
       }
      }
     },
     "auth_ref": [
      "r776"
     ]
    },
    "ecd_PnsnAdjsSvcCstMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "PnsnAdjsSvcCstMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Pension Adjustments Service Cost [Member]",
        "terseLabel": "Pension Adjustments Service Cost"
       }
      }
     },
     "auth_ref": [
      "r832"
     ]
    },
    "ecd_PnsnBnftsAdjFnTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "PnsnBnftsAdjFnTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Pension Benefits Adjustments, Footnote [Text Block]",
        "terseLabel": "Pension Benefits Adjustments, Footnote"
       }
      }
     },
     "auth_ref": [
      "r775"
     ]
    },
    "bbplc_PooledCashFundsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PooledCashFundsMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Pooled cash funds",
        "label": "Pooled Cash Funds [Member]",
        "documentation": "Pooled Cash Funds"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_PostModelAdjustmentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PostModelAdjustmentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementEconomicuncertaintyadjustmentsandOtheradjustmentsDetails",
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Post-model adjustment",
        "label": "Post Model Adjustment [Member]",
        "documentation": "Post Model Adjustment"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_PostemploymentBenefitExpenseDefinedBenefitPlans": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PostemploymentBenefitExpenseDefinedBenefitPlans",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/StaffcostsDetails": {
       "parentTag": "bbplc_StaffCompensationCosts",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails",
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Retirement benefits",
        "terseLabel": "Accruing benefits under defined benefit scheme",
        "label": "Post-employment benefit expense in profit or loss, defined benefit plans"
       }
      }
     },
     "auth_ref": [
      "r841",
      "r848"
     ]
    },
    "ifrs-full_PostemploymentMedicalDefinedBenefitPlansMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PostemploymentMedicalDefinedBenefitPlansMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Post-employment medical defined benefit plans",
        "label": "Post-employment medical defined benefit plans [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for post-employment medical defined benefit plans. [Refer: Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r611"
     ]
    },
    "bbplc_PreManagementAdjustmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PreManagementAdjustmentsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Impairment allowance pre management adjustments",
        "label": "Pre-Management Adjustments [Member]",
        "documentation": "Pre-Management Adjustments"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_PreferenceSharesAdjustmentToInterestRateBasis": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PreferenceSharesAdjustmentToInterestRateBasis",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Adjustment to interest rate basis",
        "label": "Preference Shares, Adjustment To Interest Rate Basis",
        "documentation": "Preference Shares, Adjustment To Interest Rate Basis"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_PreferenceSharesInterestRate": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PreferenceSharesInterestRate",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Preference shares interest rate",
        "label": "Preference Shares, Interest Rate",
        "documentation": "Preference Shares, Interest Rate"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_PreferenceSharesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PreferenceSharesMember",
     "presentation": [
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Preference share capital",
        "label": "Preference shares [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for equity instruments that are senior in some aspects to ordinary shares, but subordinate to debt instruments in terms of claim. [Refer: Ordinary shares [member]]"
       }
      }
     },
     "auth_ref": [
      "r886"
     ]
    },
    "bbplc_PreferenceSharesPrincipalOutstanding": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PreferenceSharesPrincipalOutstanding",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Preference shares, principal outstanding",
        "label": "Preference Shares, Principal Outstanding",
        "documentation": "Preference Shares, Principal Outstanding"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_PresentValueOfDefinedBenefitObligationMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PresentValueOfDefinedBenefitObligationMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Retirement benefit obligations",
        "verboseLabel": "Defined benefit obligations",
        "label": "Present value of defined benefit obligation [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the present value of a defined benefit obligation. The present value of a defined benefit obligation is the present value, without deducting any plan assets, of expected future payments required to settle the obligation resulting from employee service in the current and prior periods."
       }
      }
     },
     "auth_ref": [
      "r21",
      "r405"
     ]
    },
    "bbplc_PrivateEquityInvestmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PrivateEquityInvestmentsMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Private equity investments",
        "verboseLabel": "Private equities",
        "label": "Private Equity Investments [Member]",
        "documentation": "This member stands for private equity investments."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ProbabilityOfDefaultAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProbabilityOfDefaultAxis",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Probability of default [axis]",
        "label": "Probability of default [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r668",
      "r687",
      "r713"
     ]
    },
    "ifrs-full_ProbabilityOfDefaultDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProbabilityOfDefaultDomain",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Probability of default [domain]",
        "label": "Probability of default [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the standard value for the 'Probability of default' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r668",
      "r687",
      "r713"
     ]
    },
    "bbplc_ProbabilityOfDefaultElevenPointThreeFiveToOneHundredPercentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProbabilityOfDefaultElevenPointThreeFiveToOneHundredPercentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "11.35% to 100%",
        "label": "Probability Of Default Eleven Point Three Five To One Hundred Percent [Member]",
        "documentation": "This member stands for internal measures on wholesale and retail lending with a default grade betweeen 20 and 22. A probability of default between 11.35% and 100%."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ProbabilityOfDefaultForeignExchangeMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProbabilityOfDefaultForeignExchangeMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "FX - IR correlation",
        "label": "Probability Of Default Foreign Exchange, Measurement Input [Member]",
        "documentation": "This member stands for the probability of default on foreign exchange used as a measurement input."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ProbabilityOfDefaultMeasurementInputCorrelationMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProbabilityOfDefaultMeasurementInputCorrelationMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Inflation - Inflation correlation",
        "label": "Probability Of Default, Measurement Input, Correlation [Member]",
        "documentation": "Probability Of Default, Measurement Input, Correlation"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ProbabilityOfDefaultMeasurementInputInflationCorrelationMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProbabilityOfDefaultMeasurementInputInflationCorrelationMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "IR - Inflation correlation",
        "label": "Probability Of Default, Measurement Input, Inflation Correlation [Member]",
        "documentation": "Probability Of Default, Measurement Input, Inflation Correlation"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ProbabilityOfDefaultMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProbabilityOfDefaultMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "IR - IR correlation",
        "label": "Probability of default, measurement input [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the probability of default used as a measurement input."
       }
      }
     },
     "auth_ref": [
      "r639",
      "r651"
     ]
    },
    "bbplc_ProbabilityOfDefaultOneHundredPercentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProbabilityOfDefaultOneHundredPercentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "100%",
        "label": "Probability Of Default One Hundred Percent [Member]",
        "documentation": "This member stands for internal measures on wholesale and retail lending with a default grade of 22. A probability of default of 100%."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ProbabilityOfDefaultPointOneFiveToPointThreePercentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProbabilityOfDefaultPointOneFiveToPointThreePercentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "0.15 to 0.30%",
        "label": "Probability Of Default Point One Five To Point Three Percent [Member]",
        "documentation": "This member stands for internal measures on wholesale retail lending with a default grade betweeen 6 and 8. A probability of default between 0.15% and 0.30%."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ProbabilityOfDefaultPointSixtyToElevenPointThreeFivePercentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProbabilityOfDefaultPointSixtyToElevenPointThreeFivePercentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "0.60 to 11.35%",
        "label": "Probability Of Default Point Sixty To Eleven Point Three Five Percent [Member]",
        "documentation": "This member stands for internal measures on wholesale and retail lending with a default grade betweeen 12 and 19. A probability of default between 0.60% and 11.35%."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ProbabilityOfDefaultPointSixtyToTwoPointOneFivePercentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProbabilityOfDefaultPointSixtyToTwoPointOneFivePercentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "0.60 to 2.15%",
        "label": "Probability Of Default Point Sixty To Two Point One Five Percent [Member]",
        "documentation": "This member stands for internal measures on wholesale retail lending with a default grade betweeen 12 and 14. A probability of default between 0.60% and 2.15%."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ProbabilityOfDefaultPointThreeToPointSixPercentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProbabilityOfDefaultPointThreeToPointSixPercentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "0.30 to 0.60%",
        "label": "Probability Of Default Point Three To Point Six Percent [Member]",
        "documentation": "This member stands for internal measures on wholesale retail lending with a default grade betweeen 9 and 11. A probability of default between 0.30% and 0.60%."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ProbabilityOfDefaultPointZeroFiveToPointOneFivePercentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProbabilityOfDefaultPointZeroFiveToPointOneFivePercentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "0.05 to 0.15%",
        "label": "Probability Of Default Point Zero Five To Point One Five Percent [Member]",
        "documentation": "This member stands for internal measures on wholesale retail lending with a default grade betweeen 4 and 5. A probability of default between 0.05% and 0.15%."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ProbabilityOfDefaultTwoPointOneFiveToElevenPointThreeFivePercentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProbabilityOfDefaultTwoPointOneFiveToElevenPointThreeFivePercentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "2.15 to 11.35%",
        "label": "Probability Of Default Two Point One Five To Eleven Point Three Five Percent [Member]",
        "documentation": "This member stands for internal measures on wholesale retail lending with a default grade betweeen 15 and 19. A probability of default between 2.15% and 11.35%."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ProbabilityOfDefaultZeroToPointSixtyPercentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProbabilityOfDefaultZeroToPointSixtyPercentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "0.0 to 0.60%",
        "label": "Probability Of Default Zero To Point Sixty Percent [Member]",
        "documentation": "This member stands for internal measures on wholesale and retail lending with a default grade betweeen 1 and 11. A probability of default between 0.0% and .60%."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ProbabilityOfDefaultZeroToPointZeroFivePercentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProbabilityOfDefaultZeroToPointZeroFivePercentMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "0.0 to 0.05%",
        "label": "Probability Of Default Zero To Point Zero Five Percent [Member]",
        "documentation": "This member stands for internal measures on wholesale retail lending with a default grade betweeen 1 and 3. A probability of default between 0.0% and .05%."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ProceedsFromIssueOfSubordinatedLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProceedsFromIssueOfSubordinatedLiabilities",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Issuance of subordinated liabilities",
        "verboseLabel": "Issuances",
        "label": "Proceeds from issue of subordinated liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash inflow from the issuing of subordinated liabilities. [Refer: Subordinated liabilities]"
       }
      }
     },
     "auth_ref": [
      "r864"
     ]
    },
    "ifrs-full_ProceedsFromIssuingShares": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProceedsFromIssuingShares",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Issue of shares and other equity instruments",
        "terseLabel": "Proceeds from issuing shares",
        "label": "Proceeds from issuing shares"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash inflow from issuing shares."
       }
      }
     },
     "auth_ref": [
      "r628"
     ]
    },
    "ifrs-full_ProceedsFromSalesOrMaturityOfFinancialAssetsMeasuredAtAmortisedCostClassifiedAsInvestingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProceedsFromSalesOrMaturityOfFinancialAssetsMeasuredAtAmortisedCostClassifiedAsInvestingActivities",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Proceeds from redemption or sale of debt securities at amortised cost",
        "label": "Proceeds from sales or maturity of financial assets measured at amortised cost, classified as investing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash inflow from sales or maturity of financial assets measured at amortised cost, classified as investing activities."
       }
      }
     },
     "auth_ref": [
      "r863"
     ]
    },
    "ifrs-full_ProceedsFromSalesOrMaturityOfFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeClassifiedAsInvestingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProceedsFromSalesOrMaturityOfFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeClassifiedAsInvestingActivities",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": 1.0,
       "order": 4.0
      },
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Proceeds from sale or redemption of financial assets at fair value through other comprehensive income",
        "label": "Proceeds from sales or maturity of financial assets measured at fair value through other comprehensive income, classified as investing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash inflow from sales or maturity of financial assets measured at fair value through other comprehensive income, classified as investing activities."
       }
      }
     },
     "auth_ref": [
      "r863"
     ]
    },
    "srt_ProductOrServiceAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "ProductOrServiceAxis",
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails",
      "http://www.home.barclays/role/AuditorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Product and Service [Axis]",
        "label": "Product and Service [Axis]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ProductsAndServicesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProductsAndServicesAxis",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Products and services [axis]",
        "label": "Products and services [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r342",
      "r652",
      "r697"
     ]
    },
    "srt_ProductsAndServicesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "ProductsAndServicesDomain",
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails",
      "http://www.home.barclays/role/AuditorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Product and Service [Domain]",
        "label": "Product and Service [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ProductsAndServicesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProductsAndServicesDomain",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Products and services [domain]",
        "label": "Products and services [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the entity's products and services. It also represents the standard value for the 'Products and services' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r342",
      "r652",
      "r697"
     ]
    },
    "ifrs-full_ProfessionalFeesExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProfessionalFeesExpense",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails": {
       "parentTag": "ifrs-full_SellingGeneralAndAdministrativeExpense",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Consultancy, legal and professional fees",
        "label": "Professional fees expense"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "ifrs-full_ProfitLoss": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProfitLoss",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity": {
       "parentTag": "ifrs-full_ComprehensiveIncome",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_ComprehensiveIncome",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      },
      "http://www.home.barclays/role/ConsolidatedincomestatementAlternativeCalculation": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsbalancesheetParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Profit after tax",
        "terseLabel": "Profit after tax",
        "label": "Profit (loss)"
       }
      },
      "en": {
       "role": {
        "documentation": "The total of income less expenses from continuing and discontinued operations, excluding the components of other comprehensive income. [Refer: Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r131",
      "r133",
      "r335",
      "r337",
      "r430",
      "r460",
      "r551",
      "r587",
      "r635",
      "r655"
     ]
    },
    "ifrs-full_ProfitLossAttributableToAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProfitLossAttributableToAbstract",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Attributable to:",
        "label": "Profit (loss), attributable to [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntity": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntity",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Equity holders of the parent",
        "label": "Profit (loss), attributable to ordinary equity holders of parent entity, used in calculating basic earnings per share"
       }
      },
      "en": {
       "role": {
        "documentation": "The profit (loss) attributable to ordinary equity holders of the parent entity. [Refer: Profit (loss)]"
       }
      }
     },
     "auth_ref": [
      "r68"
     ]
    },
    "ifrs-full_ProfitLossAttributableToOwnersOfParent": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProfitLossAttributableToOwnersOfParent",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/ConsolidatedincomestatementAlternativeCalculation": {
       "parentTag": "ifrs-full_ProfitLoss",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_ProfitLossAttributableToOrdinaryEquityHoldersOfParentEntity",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total equity holders of the parent",
        "label": "Profit (loss), attributable to owners of parent"
       }
      },
      "en": {
       "role": {
        "documentation": "The profit (loss) from continuing and discontinued operations attributable to owners of the parent. [Refer: Profit (loss)]"
       }
      }
     },
     "auth_ref": [
      "r590"
     ]
    },
    "ifrs-full_ProfitLossBeforeTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProfitLossBeforeTax",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_ProfitLoss",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInOperatingActivities",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails",
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Profit/(loss) before tax",
        "verboseLabel": "Profit before tax",
        "terseLabel": "Profit before tax from continuing operations",
        "label": "Profit (loss) before tax"
       }
      }
     },
     "auth_ref": [
      "r232",
      "r693",
      "r694",
      "r716",
      "r717"
     ]
    },
    "bbplc_ProfitLossFromOperatingActivitiesBeforeImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProfitLossFromOperatingActivitiesBeforeImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_ProfitLossBeforeTax",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Profit before Impairment",
        "label": "Profit (Loss) From Operating Activities Before Impairment Loss (Reversal Of Impairment Loss) Recognised In Profit Or Loss",
        "documentation": "The profit (loss) from operating activities of the entity, before impairment loss (reversal of impairment loss) recognised in profit or loss."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_PropertyAmountContributedToFairValueOfPlanAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PropertyAmountContributedToFairValueOfPlanAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails": {
       "parentTag": "ifrs-full_PlanAssetsAtFairValue",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Property",
        "label": "Real estate, amount contributed to fair value of plan assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount real estate contributes to the fair value of defined benefit plan assets. [Refer: Plan assets, at fair value; Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r616",
      "r704"
     ]
    },
    "ifrs-full_PropertyPlantAndEquipment": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PropertyPlantAndEquipment",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails": {
       "parentTag": "ifrs-full_NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSale",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Property, plant and equipment",
        "label": "Property, plant and equipment"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of tangible assets that: (a) are held for use in the production or supply of goods or services, for rental to others, or for administrative purposes; and (b) are expected to be used during more than one period. Note that right-of-use assets are not included. [Contrast: Property, plant and equipment including right-of-use assets]"
       }
      }
     },
     "auth_ref": [
      "r15",
      "r401",
      "r564"
     ]
    },
    "ifrs-full_PropertyPlantAndEquipmentIncludingRightofuseAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PropertyPlantAndEquipmentIncludingRightofuseAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 14.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Property, plant and equipment",
        "periodStartLabel": "Beginning balance, Property, plant and equipment",
        "periodEndLabel": "Ending balance, Property, plant and equipment",
        "label": "Property, plant and equipment including right-of-use assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of property, plant and equipment including right-of-use assets whose underlying assets would be presented as property, plant and equipment if they were owned. [Refer: Property, plant and equipment; Right-of-use assets]"
       }
      }
     },
     "auth_ref": [
      "r188",
      "r840",
      "r882"
     ]
    },
    "ifrs-full_PropertyPlantAndEquipmentIncludingRightofuseAssetsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PropertyPlantAndEquipmentIncludingRightofuseAssetsAxis",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Property, plant and equipment including right-of-use assets [axis]",
        "label": "Property, plant and equipment including right-of-use assets [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r840"
     ]
    },
    "ifrs-full_PropertyPlantAndEquipmentIncludingRightofuseAssetsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PropertyPlantAndEquipmentIncludingRightofuseAssetsDomain",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Property, plant and equipment including right-of-use assets [domain]",
        "label": "Property, plant and equipment including right-of-use assets [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a class of asset representing property, plant and equipment including right-of-use assets whose underlying assets would be presented as property, plant and equipment if they were owned. [Refer: Property, plant and equipment including right-of-use assets]"
       }
      }
     },
     "auth_ref": [
      "r840"
     ]
    },
    "ifrs-full_PropertyPlantAndEquipmentMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PropertyPlantAndEquipmentMember",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Property, plant and equipment",
        "label": "Property, plant and equipment [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for property, plant and equipment. [Refer: Property, plant and equipment]"
       }
      }
     },
     "auth_ref": [
      "r16",
      "r402",
      "r621",
      "r654",
      "r699",
      "r705"
     ]
    },
    "bbplc_ProportionOfOwnershipInterestHeldInSignificantInvestments": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProportionOfOwnershipInterestHeldInSignificantInvestments",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Proportion of ownership interest held in significant investments",
        "label": "Proportion Of Ownership Interest Held In Significant Investments",
        "documentation": "Proportion Of Ownership Interest Held In Significant Investments"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ProportionOfOwnershipInterestInAssociate": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProportionOfOwnershipInterestInAssociate",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Proportion of ownership interest in associate",
        "label": "Proportion of ownership interest in associate"
       }
      },
      "en": {
       "role": {
        "documentation": "The proportion of ownership interest in an associate attributable to the entity. [Refer: Total for all associates [member]]"
       }
      }
     },
     "auth_ref": [
      "r64",
      "r66",
      "r141"
     ]
    },
    "ifrs-full_ProportionOfOwnershipInterestInSubsidiary": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProportionOfOwnershipInterestInSubsidiary",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Proportion of ownership interest in subsidiary",
        "label": "Proportion of ownership interest in subsidiary"
       }
      },
      "en": {
       "role": {
        "documentation": "The proportion of ownership interest in a subsidiary attributable to the entity. [Refer: Total for all subsidiaries [member]]"
       }
      }
     },
     "auth_ref": [
      "r64",
      "r66",
      "r137"
     ]
    },
    "ifrs-full_ProportionOfOwnershipInterestsHeldByNoncontrollingInterests": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProportionOfOwnershipInterestsHeldByNoncontrollingInterests",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-controlling interests - proportion of ownership interests",
        "label": "Proportion of ownership interests held by non-controlling interests"
       }
      },
      "en": {
       "role": {
        "documentation": "The proportion of ownership interests in a subsidiary held by non-controlling interests. [Refer: Total for all subsidiaries [member]; Non-controlling interests]"
       }
      }
     },
     "auth_ref": [
      "r135"
     ]
    },
    "ifrs-full_ProportionOfVotingPowerHeldInSubsidiary": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProportionOfVotingPowerHeldInSubsidiary",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Proportion of voting rights held in subsidiary",
        "verboseLabel": "Percentage of voting rights held",
        "label": "Proportion of voting rights held in subsidiary"
       }
      },
      "en": {
       "role": {
        "documentation": "The proportion of the voting rights in a subsidiary held by the entity. [Refer: Total for all subsidiaries [member]]"
       }
      }
     },
     "auth_ref": [
      "r64",
      "r66",
      "r137"
     ]
    },
    "ifrs-full_ProportionOfVotingRightsHeldByNoncontrollingInterests": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProportionOfVotingRightsHeldByNoncontrollingInterests",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-controlling interests - proportion of voting interests",
        "label": "Proportion of voting rights held by non-controlling interests"
       }
      },
      "en": {
       "role": {
        "documentation": "The proportion of the voting rights in a subsidiary held by non-controlling interests. [Refer: Total for all subsidiaries [member]; Non-controlling interests]"
       }
      }
     },
     "auth_ref": [
      "r136"
     ]
    },
    "ifrs-full_ProvisionForCreditCommitmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProvisionForCreditCommitmentsMember",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsNarrativeDetails",
      "http://www.home.barclays/role/ProvisionsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Expected credit losses held against contingent liabilities and commitments",
        "label": "Provision for credit commitments [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a provision for credit commitments entered into by the entity. [Refer: Classes of other provisions [domain]]"
       }
      }
     },
     "auth_ref": [
      "r853"
     ]
    },
    "ifrs-full_ProvisionUsedOtherProvisions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProvisionUsedOtherProvisions",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Amounts utilised",
        "label": "Provision used, other provisions"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount used (ie incurred and charged against the provision) for other provisions. [Refer: Other provisions]"
       }
      }
     },
     "auth_ref": [
      "r93",
      "r443"
     ]
    },
    "ifrs-full_Provisions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "Provisions",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails": {
       "parentTag": "ifrs-full_LiabilitiesIncludedInDisposalGroupsClassifiedAsHeldForSale",
       "weight": 1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 13.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/AssetsandliabilitiesincludedindisposalgroupclassifiedasheldforsaleDetails",
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsNarrativeDetails",
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails",
      "http://www.home.barclays/role/ProvisionsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Provisions",
        "periodStartLabel": "Provisions, beginning balance",
        "periodEndLabel": "Provisions, ending balance",
        "label": "Provisions"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of liabilities of uncertain timing or amount, including provisions for employee benefits."
       }
      }
     },
     "auth_ref": [
      "r570"
     ]
    },
    "ifrs-full_ProvisionsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ProvisionsAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Provisions [abstract]",
        "label": "Provisions [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ProvisionsOtherThanUndrawnContractuallyCommittedFacilitiesAndGuaranteesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ProvisionsOtherThanUndrawnContractuallyCommittedFacilitiesAndGuaranteesMember",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Provisions other than undrawn contractually committed facilities and guarantees",
        "label": "Provisions Other Than Undrawn Contractually Committed Facilities And Guarantees [Member]",
        "documentation": "Provisions Other Than Undrawn Contractually Committed Facilities And Guarantees"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_PurchaseOfFinancialAssetsMeasuredAtAmortisedCostClassifiedAsInvestingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PurchaseOfFinancialAssetsMeasuredAtAmortisedCostClassifiedAsInvestingActivities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": -1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": -1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Purchase of debt securities at amortised cost",
        "label": "Purchase of financial assets measured at amortised cost, classified as investing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash outflow for the purchase of financial assets measured at amortised cost, classified as investing activities."
       }
      }
     },
     "auth_ref": [
      "r863"
     ]
    },
    "ifrs-full_PurchaseOfFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeClassifiedAsInvestingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PurchaseOfFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeClassifiedAsInvestingActivities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": -1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": -1.0,
       "order": 6.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Purchase of financial assets at fair value through other comprehensive income",
        "label": "Purchase of financial assets measured at fair value through other comprehensive income, classified as investing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash outflow for the purchase of financial assets measured at fair value through other comprehensive income, classified as investing activities."
       }
      }
     },
     "auth_ref": [
      "r863"
     ]
    },
    "ifrs-full_PurchaseOfPropertyPlantAndEquipmentIntangibleAssetsOtherThanGoodwillInvestmentPropertyAndOtherNoncurrentAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PurchaseOfPropertyPlantAndEquipmentIntangibleAssetsOtherThanGoodwillInvestmentPropertyAndOtherNoncurrentAssets",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": -1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInInvestingActivities",
       "weight": -1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Purchase of property, plant and equipment and investment in intangibles",
        "label": "Purchase of property, plant and equipment, intangible assets other than goodwill, investment property and other non-current assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash outflow for the purchase of property, plant and equipment, intangible assets other than goodwill, investment property and other non-current assets. [Refer: Intangible assets other than goodwill; Investment property; Other non-current assets; Property, plant and equipment]"
       }
      }
     },
     "auth_ref": [
      "r863"
     ]
    },
    "ifrs-full_PurchasesFairValueMeasurementAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PurchasesFairValueMeasurementAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Purchases, fair value measurement, assets",
        "label": "Purchases, fair value measurement, assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase in the fair value measurement of assets resulting from purchases of those assets. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r168"
     ]
    },
    "bbplc_PurchasesFairValueMeasurementAssetsLiabilitiesNet": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "PurchasesFairValueMeasurementAssetsLiabilitiesNet",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Purchases, fair value measurement, assets (liabilities) net",
        "label": "Purchases, Fair Value Measurement, Assets (Liabilities) Net",
        "documentation": "The increase in the fair value measurement of assets and liabilities resulting from purchases of those assets and liabilities. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_PurchasesFairValueMeasurementLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "PurchasesFairValueMeasurementLiabilities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Purchases, fair value measurement, liabilities",
        "label": "Purchases, fair value measurement, liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The increase in the fair value measurement of liabilities resulting from purchases of those liabilities. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r168"
     ]
    },
    "ecd_PvpTable": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "PvpTable",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Pay vs Performance Disclosure [Table]",
        "terseLabel": "Pay vs Performance Disclosure"
       }
      }
     },
     "auth_ref": [
      "r773"
     ]
    },
    "ecd_PvpTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "PvpTableTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Pay vs Performance [Table Text Block]",
        "terseLabel": "Pay vs Performance Disclosure, Table"
       }
      }
     },
     "auth_ref": [
      "r773"
     ]
    },
    "ifrs-full_QualifyingInsurancePoliciesAmountContributedToFairValueOfPlanAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "QualifyingInsurancePoliciesAmountContributedToFairValueOfPlanAssets",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails": {
       "parentTag": "ifrs-full_PlanAssetsAtFairValue",
       "weight": 1.0,
       "order": 7.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Longevity reinsurance contracts",
        "label": "Qualifying insurance policies, amount contributed to fair value of plan assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount qualifying insurance policies contribute to the fair value of defined benefit plan assets. [Refer: Plan assets, at fair value; Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r845",
      "r850"
     ]
    },
    "ifrs-full_RangeAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RangeAxis",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsNarrativeDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails",
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Range [axis]",
        "label": "Range [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r127",
      "r177",
      "r202",
      "r222",
      "r386",
      "r649",
      "r651",
      "r875"
     ]
    },
    "srt_RangeAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "RangeAxis",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Statistical Measurement [Axis]",
        "label": "Statistical Measurement [Axis]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_RangeDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RangeDomain",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsNarrativeDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails",
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Range [domain]",
        "label": "Range [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for aggregate ranges. It also represents the standard value for the 'Range' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r127",
      "r177",
      "r202",
      "r222",
      "r386",
      "r649",
      "r651",
      "r875"
     ]
    },
    "srt_RangeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "RangeMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Statistical Measurement [Domain]",
        "label": "Statistical Measurement [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReceivablesPayablesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReceivablesPayablesMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Receivables/payables",
        "label": "Receivables (Payables) [Member]",
        "documentation": "Receivables (Payables)"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ReclassificationAdjustmentsOnCashFlowHedgesBeforeTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReclassificationAdjustmentsOnCashFlowHedgesBeforeTax",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 8.0
      },
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 9.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectonthereservesasaresultofhedgeaccountingDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Net (gains)/losses transferred to net profit",
        "negatedLabel": "Net (losses)/gains transferred to net profit",
        "negatedNetLabel": "Amounts reclassified in relation to cash flows affecting profit or loss",
        "label": "Reclassification adjustments on cash flow hedges, before tax"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of reclassification adjustments related to cash flow hedges, before tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Cash flow hedges [member]; Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r601"
     ]
    },
    "ifrs-full_ReclassificationAdjustmentsOnCashFlowHedgesForWhichHedgedFutureCashFlowsAreNoLongerExpectedToOccurNetOfTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReclassificationAdjustmentsOnCashFlowHedgesForWhichHedgedFutureCashFlowsAreNoLongerExpectedToOccurNetOfTax",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Amount recycled from OCI due to sale of investment, or cash flows no longer expected to occur, cash flow hedges",
        "label": "Reclassification adjustments on cash flow hedges for which hedged future cash flows are no longer expected to occur, net of tax"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of reclassification adjustments on cash flow hedges for which the hedged future cash flows are no longer expected to occur, net of tax. [Refer: Reclassification adjustments on cash flow hedges, net of tax]"
       }
      }
     },
     "auth_ref": [
      "r270",
      "r272",
      "r502"
     ]
    },
    "ifrs-full_ReclassificationAdjustmentsOnCashFlowHedgesForWhichHedgedItemAffectedProfitOrLossNetOfTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReclassificationAdjustmentsOnCashFlowHedgesForWhichHedgedItemAffectedProfitOrLossNetOfTax",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Amount recycled from OCI due to hedged item affecting income statement, cash flow hedges",
        "label": "Reclassification adjustments on cash flow hedges for which hedged item affected profit or loss, net of tax"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of reclassification adjustments on cash flow hedges for which the hedged item affected profit or loss, net of tax. [Refer: Reclassification adjustments on cash flow hedges, net of tax]"
       }
      }
     },
     "auth_ref": [
      "r270",
      "r272",
      "r502"
     ]
    },
    "ifrs-full_ReclassificationAdjustmentsOnExchangeDifferencesOnTranslationNetOfTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReclassificationAdjustmentsOnExchangeDifferencesOnTranslationNetOfTax",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/ConsolidatedstatementofcomprehensiveincomeParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Gain (loss) on recycling of currency translation differences",
        "label": "Reclassification adjustments on exchange differences on translation of foreign operations, net of tax"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of reclassification adjustments related to exchange differences when the financial statements of foreign operations are translated, net of tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r40",
      "r601"
     ]
    },
    "bbplc_ReclassificationAdjustmentsOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTaxDueToFairValueHedging": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReclassificationAdjustmentsOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTaxDueToFairValueHedging",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 5.0
      },
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 6.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Net gains/(losses) due to fair value hedging",
        "negatedLabel": "Net gains/(losses) due to fair value hedging",
        "label": "Reclassification Adjustments On Financial Assets Measured At Fair Value Through Other Comprehensive Income, Before Tax, Due To Fair Value Hedging",
        "documentation": "The amount of reclassification adjustments due to impairment of financial assets measured at fair value through other comprehensive income, before tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReclassificationAdjustmentsOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTaxDueToImpairment": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReclassificationAdjustmentsOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTaxDueToImpairment",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 4.0
      },
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Net (gains)/losses related to (releases of) impairment",
        "negatedLabel": "Net (gains)/losses relating to (release of) impairment",
        "label": "Reclassification Adjustments On Financial Assets Measured At Fair Value Through Other Comprehensive Income, Before Tax, Due To Impairment",
        "documentation": "The amount of reclassification adjustments due to impairment of financial assets measured at fair value through other comprehensive income, before tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReclassificationAdjustmentsOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTaxOnDisposal": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReclassificationAdjustmentsOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeBeforeTaxOnDisposal",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome": {
       "parentTag": "ifrs-full_OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
       "weight": -1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofcomprehensiveincome",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofcomprehensiveincome"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Net losses/(gains) transferred to net profit on disposal",
        "negatedLabel": "Net losses/(gains) transferred to net profit on disposal",
        "label": "Reclassification Adjustments On Financial Assets Measured At Fair Value Through Other Comprehensive Income, Before Tax, On Disposal",
        "documentation": "The amount of reclassification adjustments due to disposal of financial assets measured at fair value through other comprehensive income, before tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ReclassificationAdjustmentsOnHedgesOfNetInvestmentsInForeignOperationsBeforeTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReclassificationAdjustmentsOnHedgesOfNetInvestmentsInForeignOperationsBeforeTax",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectonthereservesasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Amounts reclassified in relation to cash flows affecting profit or loss",
        "label": "Reclassification adjustments on hedges of net investments in foreign operations, before tax"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of reclassification adjustments related to hedges of net investments in foreign operations, before tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r107",
      "r350",
      "r601"
     ]
    },
    "bbplc_ReclassificationAdjustmentsOnHedgesOfNetInvestmentsInForeignOperationsForWhichHedgedFutureCashFlowsAreNoLongerExpectedToOccurNetOfTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReclassificationAdjustmentsOnHedgesOfNetInvestmentsInForeignOperationsForWhichHedgedFutureCashFlowsAreNoLongerExpectedToOccurNetOfTax",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Amount recycled from OCI due to sale of investment, or cash flows no longer expected to occur, hedges of net investments in foreign operations",
        "label": "Reclassification Adjustments On Hedges Of Net Investments In Foreign Operations For Which Hedged Future Cash Flows Are No Longer Expected To Occur, Net Of Tax",
        "documentation": "The amount of reclassification adjustments on hedges of net investments in foreign operations for which the hedged future cash flows are no longer expected to occur, net of tax."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ReclassificationAdjustmentsOnHedgesOfNetInvestmentsInForeignOperationsNetOfTax": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReclassificationAdjustmentsOnHedgesOfNetInvestmentsInForeignOperationsNetOfTax",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Amount recycled from OCI due to hedged item affecting income statement, hedges of net investments in foreign operations",
        "label": "Reclassification adjustments on hedges of net investments in foreign operations, net of tax"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of reclassification adjustments related to hedges of net investments in foreign operations, net of tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r107",
      "r270",
      "r272",
      "r350",
      "r502",
      "r601"
     ]
    },
    "ifrs-full_RecognisedAssetsDefinedBenefitPlan": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RecognisedAssetsDefinedBenefitPlan",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails": {
       "parentTag": "ifrs-full_LiabilityAssetOfDefinedBenefitPlans",
       "weight": -1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 17.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Retirement benefit assets",
        "terseLabel": "Retirement benefit assets",
        "label": "Net defined benefit asset"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_RecognisedAssetsRepresentingContinuingInvolvementInDerecognisedFinancialAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RecognisedAssetsRepresentingContinuingInvolvementInDerecognisedFinancialAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureofcontinuinginvolvementinfinancialassetsthathavebeenderecognisedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Carrying amount",
        "label": "Recognised assets representing continuing involvement in derecognised financial assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of assets recognised in the statement of financial position representing the entity's continuing involvement in derecognised financial assets."
       }
      }
     },
     "auth_ref": [
      "r304"
     ]
    },
    "ifrs-full_RecognisedLiabilitiesDefinedBenefitPlan": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RecognisedLiabilitiesDefinedBenefitPlan",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails": {
       "parentTag": "ifrs-full_LiabilityAssetOfDefinedBenefitPlans",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 12.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Retirement benefit liabilities",
        "negatedTerseLabel": "Retirement benefit liabilities",
        "label": "Net defined benefit liability"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of deficit in a defined benefit plan. [Refer: Defined benefit plans [domain]]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_ReconciliationOfChangesInDeferredTaxLiabilityAssetAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReconciliationOfChangesInDeferredTaxLiabilityAssetAbstract",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation of changes in deferred tax liability (asset) [abstract]",
        "label": "Reconciliation of changes in deferred tax liability (asset) [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ReconciliationOfChangesInFairValueMeasurementAssetsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReconciliationOfChangesInFairValueMeasurementAssetsAbstract",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation of changes in fair value measurement, assets [abstract]",
        "label": "Reconciliation of changes in fair value measurement, assets [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReconciliationOfChangesInFairValueMeasurementAssetsLiabilitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReconciliationOfChangesInFairValueMeasurementAssetsLiabilitiesAbstract",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation of changes in fair value measurement, assets (liabilities)",
        "label": "Reconciliation Of Changes In Fair Value Measurement, Assets (Liabilities) [Abstract]",
        "documentation": "Reconciliation Of Changes In Fair Value Measurement, Assets (Liabilities)"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ReconciliationOfChangesInFairValueMeasurementLiabilitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReconciliationOfChangesInFairValueMeasurementLiabilitiesAbstract",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation of changes in fair value measurement, liabilities [abstract]",
        "label": "Reconciliation of changes in fair value measurement, liabilities [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ReconciliationOfChangesInIntangibleAssetsAndGoodwillAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReconciliationOfChangesInIntangibleAssetsAndGoodwillAbstract",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofreconciliationofchangesinintangibleassetsandgoodwillDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation of changes in intangible assets and goodwill [abstract]",
        "label": "Reconciliation of changes in intangible assets and goodwill [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ReconciliationOfChangesInNetAssetsAvailableForBenefitsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReconciliationOfChangesInNetAssetsAvailableForBenefitsAbstract",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation of changes in net assets available for benefits [abstract]",
        "label": "Reconciliation of changes in net assets available for benefits [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ReconciliationOfChangesInOtherProvisionsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReconciliationOfChangesInOtherProvisionsAbstract",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation of changes in other provisions [abstract]",
        "label": "Reconciliation of changes in other provisions [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ReconciliationOfChangesInPropertyPlantAndEquipmentAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReconciliationOfChangesInPropertyPlantAndEquipmentAbstract",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation of changes in property, plant and equipment [abstract]",
        "label": "Reconciliation of changes in property, plant and equipment [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReconciliationOfCurrencyTranslationReserveRollForward": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReconciliationOfCurrencyTranslationReserveRollForward",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectonthereservesasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Currency translation reserve",
        "label": "Reconciliation Of Currency Translation Reserve [Roll Forward]",
        "documentation": "Reconciliation Of Currency Translation Reserve"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReconciliationOfEquityInstrumentsRollForward": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReconciliationOfEquityInstrumentsRollForward",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation of equity instruments [Roll Forward]",
        "label": "Reconciliation Of Equity Instruments [Roll Forward]",
        "documentation": "Reconciliation Of Equity Instruments"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReconciliationOfHedgingReserveAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReconciliationOfHedgingReserveAbstract",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectonthereservesasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash flow hedging reserve",
        "label": "Reconciliation Of Hedging Reserve [Abstract]",
        "documentation": "Reconciliation Of Hedging Reserve"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReconciliationOfLeaseLiabilitiesRollForward": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReconciliationOfLeaseLiabilitiesRollForward",
     "presentation": [
      "http://www.home.barclays/role/LeasesDisclosureofleaseliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation Of Lease Liabilities [Roll Forward]",
        "label": "Reconciliation Of Lease Liabilities [Roll Forward]",
        "documentation": "Reconciliation Of Lease Liabilities"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReconciliationOfOptionsAndAwardPlansRollForward": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReconciliationOfOptionsAndAwardPlansRollForward",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation of options and award plans [Roll Forward]",
        "label": "Reconciliation Of Options And Award Plans [Roll Forward]",
        "documentation": "Reconciliation Of Options And Award Plans"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReconciliationOfSharePriceOfOptionsAndAwardPlansRollForward": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReconciliationOfSharePriceOfOptionsAndAwardPlansRollForward",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reconciliation of share price of options and award plans [Roll Forward]",
        "label": "Reconciliation Of Share Price Of Options And Award Plans [Roll Forward]",
        "documentation": "Reconciliation Of Share Price Of Options And Award Plans"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_RecoverableAmountOfAssetOrCashgeneratingUnit": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RecoverableAmountOfAssetOrCashgeneratingUnit",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Value in use",
        "terseLabel": "Value in use",
        "label": "Recoverable amount of asset or cash-generating unit"
       }
      },
      "en": {
       "role": {
        "documentation": "The higher of an asset\u2019s (or cash-generating unit\u2019s) fair value less costs of disposal and its value in use. [Refer: Total for all cash-generating units [member]]"
       }
      }
     },
     "auth_ref": [
      "r76"
     ]
    },
    "ecd_RecoveryOfErrCompDisclosureLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "RecoveryOfErrCompDisclosureLineItems",
     "lang": {
      "en-us": {
       "role": {
        "label": "Recovery of Erroneously Awarded Compensation Disclosure [Line Items]",
        "terseLabel": "Recovery of Erroneously Awarded Compensation Disclosure"
       }
      }
     },
     "auth_ref": [
      "r740",
      "r751",
      "r761",
      "r794"
     ]
    },
    "ifrs-full_RecurringFairValueMeasurementMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RecurringFairValueMeasurementMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Recurring fair value measurement",
        "label": "Recurring fair value measurement [member]"
       }
      }
     },
     "auth_ref": [
      "r162",
      "r530"
     ]
    },
    "bbplc_RecurringItemsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "RecurringItemsAbstract",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Recurring items:",
        "label": "Recurring Items [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_RecurringItemsPercentagesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "RecurringItemsPercentagesAbstract",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Recurring items, percentages",
        "label": "Recurring Items, Percentages [Abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ReductionOfIssuedCapital": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReductionOfIssuedCapital",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "AT1 securities redemption",
        "label": "Reduction of issued capital"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease in equity resulting from a reduction in issued capital. [Refer: Issued capital]"
       }
      }
     },
     "auth_ref": [
      "r879"
     ]
    },
    "ifrs-full_RentDeferredIncome": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RentDeferredIncome",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/OtherliabilitiesDetails": {
       "parentTag": "ifrs-full_OtherLiabilities",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/OtherliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Lease liabilities (refer to Note 19)",
        "label": "Rent deferred income"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of deferred income arising on rental activity. [Refer: Deferred income other than contract liabilities]"
       }
      }
     },
     "auth_ref": [
      "r885"
     ]
    },
    "ifrs-full_RepaymentsOfBorrowingsClassifiedAsFinancingActivities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RepaymentsOfBorrowingsClassifiedAsFinancingActivities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Redemptions",
        "label": "Repayments of borrowings, classified as financing activities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash outflow to settle borrowings, classified as financing activities. [Refer: Borrowings]"
       }
      }
     },
     "auth_ref": [
      "r630"
     ]
    },
    "ifrs-full_RepaymentsOfSubordinatedLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RepaymentsOfSubordinatedLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashFlowsFromUsedInFinancingActivities",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Redemption of subordinated liabilities",
        "terseLabel": "Redemption of subordinated debt",
        "label": "Repayments of subordinated liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The cash outflow for repayments of subordinated liabilities. [Refer: Subordinated liabilities]"
       }
      }
     },
     "auth_ref": [
      "r864"
     ]
    },
    "bbplc_RepoRateShareOptionsGranted": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "RepoRateShareOptionsGranted",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Repo rates",
        "label": "Repo Rate, Share Options Granted",
        "documentation": "Repo Rate, Share Options Granted"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_RepoSpreadMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "RepoSpreadMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Repo spread",
        "label": "Repo Spread, Measurement Input [Member]",
        "documentation": "Repo Spread"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReposMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReposMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Repurchase agreements",
        "label": "Repos [Member]",
        "documentation": "Repos"
       }
      }
     },
     "auth_ref": []
    },
    "srt_RepurchaseAgreementCounterpartyNameDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "RepurchaseAgreementCounterpartyNameDomain",
     "presentation": [
      "http://www.home.barclays/role/AcquisitionandDisposalsofsubsidiariesDetails",
      "http://www.home.barclays/role/AuditorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Counterparty Name [Domain]",
        "label": "Counterparty Name [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_RepurchaseAgreementsAndCashCollateralOnSecuritiesLent": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RepurchaseAgreementsAndCashCollateralOnSecuritiesLent",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialLiabilities",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails": {
       "parentTag": "ifrs-full_FinancialLiabilitiesAtFairValueThroughProfitOrLossDesignatedAsUponInitialRecognition",
       "weight": 1.0,
       "order": 3.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 4.0
      },
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Repurchase agreements and other similar secured borrowing at amortised cost",
        "verboseLabel": "Repurchase agreements and other similar secured borrowing",
        "negatedLabel": "Repurchase agreements and other similar secured borrowing",
        "totalLabel": "Repurchase agreements and other similar secured borrowing",
        "label": "Repurchase agreements and cash collateral on securities lent"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of instruments sold with the intent to reacquire in repurchase agreements and cash collateral on securities lent."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_RepurchaseAgreementsAndOtherSimilarSecuredBorrowingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "RepurchaseAgreementsAndOtherSimilarSecuredBorrowingMember",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Repurchase agreements and other similar secured borrowing",
        "label": "Repurchase Agreements And Other Similar Secured Borrowing [Member]",
        "documentation": "This member stands for instruments sold with the intent to reacquire in repurchase agreements and on similar securities lent."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_RepurchaseAgreementsAndOtherSimilarSecuredLending": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "RepurchaseAgreementsAndOtherSimilarSecuredLending",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails": {
       "parentTag": "bbplc_TotalFinancialLiabilitiesUndiscounted",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Repurchase agreements and other similar secured borrowing, undiscounted",
        "label": "Repurchase Agreements And Other Similar Secured Lending",
        "documentation": "The amount of contractual undiscounted cash flows in relation to repurchase agreements and other similar secured lending."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_RepurchaseAndReverseRepurchaseAgreementsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "RepurchaseAndReverseRepurchaseAgreementsMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reverse repurchase and repurchase agreements",
        "label": "Repurchase And Reverse Repurchase Agreements [Member]",
        "documentation": "Repurchase And Reverse Repurchase Agreements"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ReserveOfCashFlowHedges": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReserveOfCashFlowHedges",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectonthereservesasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "periodStartLabel": "Reserve of cash flow hedges, beginning of period",
        "periodEndLabel": "Reserve of cash flow hedges, end of period",
        "label": "Reserve of cash flow hedges"
       }
      },
      "en": {
       "role": {
        "documentation": "A component of equity representing the accumulated portion of gain (loss) on a hedging instrument that is determined to be an effective hedge for cash flow hedges. [Refer: Cash flow hedges [member]]"
       }
      }
     },
     "auth_ref": [
      "r348",
      "r884"
     ]
    },
    "ifrs-full_ReserveOfCashFlowHedgesContinuingHedges": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReserveOfCashFlowHedgesContinuingHedges",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Balance in cash flow hedging reserve for continuing hedges",
        "label": "Reserve of cash flow hedges, continuing hedges"
       }
      },
      "en": {
       "role": {
        "documentation": "A component of equity representing the reserve of cash flow hedges in relation to continuing hedges. [Refer: Reserve of cash flow hedges]"
       }
      }
     },
     "auth_ref": [
      "r265"
     ]
    },
    "ifrs-full_ReserveOfCashFlowHedgesHedgingRelationshipsForWhichHedgeAccountingIsNoLongerApplied": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReserveOfCashFlowHedgesHedgingRelationshipsForWhichHedgeAccountingIsNoLongerApplied",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Balances remaining in cash flow hedging reserve for which hedge accounting is no longer applied",
        "label": "Reserve of cash flow hedges, hedging relationships for which hedge accounting is no longer applied"
       }
      },
      "en": {
       "role": {
        "documentation": "A component of equity representing the reserve of cash flow hedges in relation to hedging relationships for which hedge accounting is no longer applied. [Refer: Reserve of cash flow hedges]"
       }
      }
     },
     "auth_ref": [
      "r266"
     ]
    },
    "ifrs-full_ReserveOfCashFlowHedgesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReserveOfCashFlowHedgesMember",
     "presentation": [
      "http://www.home.barclays/role/ReservesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash flow hedging reserve",
        "label": "Reserve of cash flow hedges [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a component of equity representing the accumulated portion of gain (loss) on a hedging instrument that is determined to be an effective hedge for cash flow hedges. [Refer: Cash flow hedges [member]]"
       }
      }
     },
     "auth_ref": [
      "r348",
      "r718"
     ]
    },
    "ifrs-full_ReserveOfChangeInFairValueOfFinancialLiabilityAttributableToChangeInCreditRiskOfLiabilityMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReserveOfChangeInFairValueOfFinancialLiabilityAttributableToChangeInCreditRiskOfLiabilityMember",
     "presentation": [
      "http://www.home.barclays/role/ReservesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Own credit reserve",
        "label": "Reserve of change in fair value of financial liability attributable to change in credit risk of liability [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a component of equity representing the accumulated change in fair value of financial liabilities attributable to change in the credit risk of the liabilities. [Refer: Credit risk [member]; Financial liabilities]"
       }
      }
     },
     "auth_ref": [
      "r718"
     ]
    },
    "ifrs-full_ReserveOfExchangeDifferencesOnTranslationContinuingHedges": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReserveOfExchangeDifferencesOnTranslationContinuingHedges",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectonthereservesasaresultofhedgeaccountingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Balance in currency translation reserve for continuing hedges",
        "periodStartLabel": "Currency translation reserve, beginning of period",
        "periodEndLabel": "Currency translation reserve, end of period",
        "label": "Reserve of exchange differences on translation, continuing hedges"
       }
      },
      "en": {
       "role": {
        "documentation": "A component of equity representing the reserve of exchange differences on translation in relation to continuing hedges. [Refer: Reserve of exchange differences on translation]"
       }
      }
     },
     "auth_ref": [
      "r265"
     ]
    },
    "ifrs-full_ReserveOfExchangeDifferencesOnTranslationHedgingRelationshipsForWhichHedgeAccountingIsNoLongerApplied": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReserveOfExchangeDifferencesOnTranslationHedgingRelationshipsForWhichHedgeAccountingIsNoLongerApplied",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Balances remaining in currency translation reserve for which hedge accounting is no longer applied",
        "label": "Reserve of exchange differences on translation, hedging relationships for which hedge accounting is no longer applied"
       }
      },
      "en": {
       "role": {
        "documentation": "A component of equity representing the reserve of exchange differences on translation in relation to hedging relationships for which hedge accounting is no longer applied. [Refer: Reserve of exchange differences on translation]"
       }
      }
     },
     "auth_ref": [
      "r266"
     ]
    },
    "ifrs-full_ReserveOfExchangeDifferencesOnTranslationMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReserveOfExchangeDifferencesOnTranslationMember",
     "presentation": [
      "http://www.home.barclays/role/ReservesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Currency translation reserve",
        "label": "Reserve of exchange differences on translation [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a component of equity representing accumulated exchange differences on the translation of financial statements recognised in other comprehensive income. [Refer: Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r41",
      "r416",
      "r718"
     ]
    },
    "ifrs-full_ReserveOfGainsAndLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReserveOfGainsAndLossesOnFinancialAssetsMeasuredAtFairValueThroughOtherComprehensiveIncomeMember",
     "presentation": [
      "http://www.home.barclays/role/ReservesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fair value through other comprehensive income reserve",
        "label": "Reserve of gains and losses on financial assets measured at fair value through other comprehensive income [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a component of equity representing the accumulated gains and losses on financial assets measured at fair value through other comprehensive income. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r718"
     ]
    },
    "ifrs-full_ReservesWithinEquityAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReservesWithinEquityAxis",
     "presentation": [
      "http://www.home.barclays/role/ReservesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reserves within equity [axis]",
        "label": "Reserves within equity [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r381",
      "r538",
      "r585"
     ]
    },
    "ifrs-full_ReservesWithinEquityDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReservesWithinEquityDomain",
     "presentation": [
      "http://www.home.barclays/role/ReservesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Reserves within equity [domain]",
        "label": "Reserves within equity [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the standard value for the 'Reserves within equity' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r381",
      "r538",
      "r585"
     ]
    },
    "bbplc_ResidentialMortgageBackedSecurities1Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ResidentialMortgageBackedSecurities1Member",
     "presentation": [
      "http://www.home.barclays/role/SecuritisationsDisclosureofcontinuinginvolvementinfinancialassetsthathavebeenderecognisedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Residential mortgage backed securities",
        "label": "Residential Mortgage Backed Securities1 [Member]",
        "documentation": "This member represents the Residential Mortgage Backed Securities."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ResourcingCosts": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ResourcingCosts",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/StaffcostsDetails": {
       "parentTag": "ifrs-full_EmployeeBenefitsExpense",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total other resourcing costs",
        "label": "Resourcing Costs",
        "documentation": "The amount of costs relating to outsourcing, redundancy and restructuring costs, and other temporary staff costs."
       }
      }
     },
     "auth_ref": []
    },
    "ecd_RestatementDateAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "RestatementDateAxis",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Restatement Determination Date [Axis]",
        "terseLabel": "Restatement Determination Date:"
       }
      }
     },
     "auth_ref": [
      "r741",
      "r752",
      "r762",
      "r795"
     ]
    },
    "ecd_RestatementDeterminationDate": {
     "xbrltype": "dateItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "RestatementDeterminationDate",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Restatement Determination Date",
        "terseLabel": "Restatement Determination Date"
       }
      }
     },
     "auth_ref": [
      "r742",
      "r753",
      "r763",
      "r796"
     ]
    },
    "ecd_RestatementDoesNotRequireRecoveryTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "RestatementDoesNotRequireRecoveryTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Restatement Does Not Require Recovery [Text Block]",
        "terseLabel": "Restatement does not require Recovery"
       }
      }
     },
     "auth_ref": [
      "r749",
      "r760",
      "r770",
      "r803"
     ]
    },
    "ifrs-full_RestructuringProvisionMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RestructuringProvisionMember",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails",
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Redundancy and restructuring",
        "label": "Restructuring provision [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a provision for restructuring, such as the sale or termination of a line of business; closure of business locations in a country or region or relocation of activities from one country or region to another; changes in management structure; and fundamental reorganisations that have a material effect on the nature and focus of the entity's operations. [Refer: Classes of other provisions [domain]]"
       }
      }
     },
     "auth_ref": [
      "r623"
     ]
    },
    "bbplc_RetailPortfoliosMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "RetailPortfoliosMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Retail portfolios",
        "label": "Retail Portfolios [member]",
        "documentation": "This member stands for the retail portfolios of the entity."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_RetainedEarnings": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RetainedEarnings",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Equity",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Retained earnings",
        "label": "Retained earnings"
       }
      },
      "en": {
       "role": {
        "documentation": "A component of equity representing the entity's cumulative undistributed earnings or deficit."
       }
      }
     },
     "auth_ref": [
      "r714",
      "r719",
      "r721"
     ]
    },
    "ifrs-full_RetainedEarningsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RetainedEarningsMember",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Retained earnings",
        "label": "Retained earnings [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a component of equity representing an entity's cumulative undistributed earnings or deficit."
       }
      }
     },
     "auth_ref": [
      "r555",
      "r718"
     ]
    },
    "ifrs-full_ReturnOnPlanAssetsNetDefinedBenefitLiabilityAsset": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReturnOnPlanAssetsNetDefinedBenefitLiabilityAsset",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Remeasurement - return on scheme assets less than discount rate",
        "label": "Decrease (increase) in net defined benefit liability (asset) resulting from return on plan assets excluding interest income or expense"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease (increase) in the net defined benefit liability (asset) resulting from the return on plan assets, excluding amounts included in interest income or expense. The return on plan assets is interest, dividends and other revenue derived from the plan assets, together with realised and unrealised gains or losses on the plan assets, less any costs of managing plan assets and less any tax payable by the plan itself, other than tax included in the actuarial assumptions used to measure the present value of the defined benefit obligation. [Refer: Plan assets [member]; Net defined benefit liability (asset); Actuarial assumptions [domain]; Increase (decrease) in net defined benefit liability (asset) resulting from interest expense (income)]"
       }
      }
     },
     "auth_ref": [
      "r25",
      "r409"
     ]
    },
    "ifrs-full_RevenueFromContractsWithCustomers": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RevenueFromContractsWithCustomers",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails": {
       "parentTag": "ifrs-full_FeeAndCommissionIncome",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total revenue from contracts with customers",
        "label": "Revenue from contracts with customers"
       }
      }
     },
     "auth_ref": [
      "r179",
      "r181",
      "r356"
     ]
    },
    "ifrs-full_RevenueFromDividends": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RevenueFromDividends",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails": {
       "parentTag": "bbplc_NetInvestmentIncomeExpense",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Dividend Income",
        "label": "Dividend income"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "ifrs-full_RevenueMultipleMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RevenueMultipleMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Equity - equity correlation",
        "label": "Revenue multiple, measurement input [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for a revenue multiple used as a measurement input."
       }
      }
     },
     "auth_ref": [
      "r639",
      "r651"
     ]
    },
    "ifrs-full_ReversalOfImpairmentLossRecognisedInProfitOrLoss": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReversalOfImpairmentLossRecognisedInProfitOrLoss",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails": {
       "parentTag": "ifrs-full_ImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Recoveries and reimbursements",
        "label": "Reversal of impairment loss recognised in profit or loss"
       }
      }
     },
     "auth_ref": [
      "r71",
      "r74",
      "r433"
     ]
    },
    "ifrs-full_ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowed",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialAssets",
       "weight": 1.0,
       "order": 4.0
      },
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails": {
       "parentTag": "ifrs-full_FinancialAssetsAtFairValueThroughProfitOrLoss",
       "weight": 1.0,
       "order": 4.0
      },
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 5.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 6.0
      },
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails": {
       "parentTag": "ifrs-full_Assets",
       "weight": 1.0,
       "order": 7.0
      },
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureoffinancialassetsdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Reverse repurchase agreements and other similar secured lending at amortised cost",
        "terseLabel": "Reverse repurchase agreements and other similar secured lending",
        "totalLabel": "Reverse repurchase agreements and other similar secured lending",
        "label": "Reverse repurchase agreements and cash collateral on securities borrowed"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of instruments purchased for resale in reverse repurchase agreements and cash collateral on securities borrowed. [Refer: Repurchase agreements and cash collateral on securities lent]"
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "bbplc_ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowedPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReverseRepurchaseAgreementsAndCashCollateralOnSecuritiesBorrowedPercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reverse repurchase agreements and other similar secured lending, percentage",
        "label": "Reverse Repurchase Agreements And Cash Collateral On Securities Borrowed, Percentage",
        "documentation": "The amount of instruments purchased for resale in reverse repurchase agreements and cash collateral on securities borrowed, expressed as a percentage."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReverseRepurchaseAgreementsAndOtherSimilarSecuredLendingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReverseRepurchaseAgreementsAndOtherSimilarSecuredLendingMember",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reverse repurchase agreements and other similar secured lending",
        "label": "Reverse Repurchase Agreements And Other Similar Secured Lending [Member]",
        "documentation": "This member stands for repurchase agreements and other similar secured lending."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReverseRepurchaseAgreementsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReverseRepurchaseAgreementsMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reverse repurchase agreements",
        "label": "Reverse Repurchase Agreements [Member]",
        "documentation": "This member stands for reverse repurchase agreements."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ReverseRepurchaseAndRepurchaseAgreementsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ReverseRepurchaseAndRepurchaseAgreementsMember",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureoftransferredfinancialassetsandtheassociatedliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Reverse repurchase and repurchase agreements",
        "verboseLabel": "Repurchase agreements",
        "label": "Reverse Repurchase And Repurchase Agreements [Member]",
        "documentation": "This member stands for securities purchased under resale agreements, securities sold under repurchase agreements, and other similar secured lending agreements."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_RightofuseAssetsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RightofuseAssetsMember",
     "presentation": [
      "http://www.home.barclays/role/PropertyplantandequipmentScheduleofreconciliationofpropertyplantandequipmentDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Right of use assets",
        "label": "Right-of-use assets [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for right-of-use assets. [Refer: Right-of-use assets]"
       }
      }
     },
     "auth_ref": [
      "r187"
     ]
    },
    "ifrs-full_RiskDiversificationEffectMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RiskDiversificationEffectMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Diversification effect",
        "label": "Risk diversification effect [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the effect of the diversification of risks arising from financial instruments. [Refer: Classes of financial instruments [domain]]"
       }
      }
     },
     "auth_ref": [
      "r872"
     ]
    },
    "ifrs-full_RiskExposuresAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RiskExposuresAxis",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Risk variables [axis]",
        "label": "Risk variables [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r208"
     ]
    },
    "ifrs-full_RiskExposuresDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "RiskExposuresDomain",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Risk variables [domain]",
        "label": "Risk variables [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the risk variables. It also represents the standard value for the 'Risk variables' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r208"
     ]
    },
    "bbplc_RiskWeightedAssets1": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "RiskWeightedAssets1",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcapitalresourcesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total risk weighted assets (RWAs)",
        "label": "Risk Weighted Assets1",
        "documentation": "The risk weighted assets of the entity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_RmbsRepurchaseRequestsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "RmbsRepurchaseRequestsMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "RMBS repurchase requests",
        "label": "RMBS Repurchase Requests [Member]",
        "documentation": "This member stands for various US residential mortgage-backed securities loan-level representations and warranties (R&amp;Ws)."
       }
      }
     },
     "auth_ref": []
    },
    "ecd_Rule10b51ArrAdoptedFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "Rule10b51ArrAdoptedFlag",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Rule 10b5-1 Arrangement Adopted [Flag]",
        "terseLabel": "Rule 10b5-1 Arrangement Adopted"
       }
      }
     },
     "auth_ref": [
      "r812"
     ]
    },
    "ecd_Rule10b51ArrTrmntdFlag": {
     "xbrltype": "booleanItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "Rule10b51ArrTrmntdFlag",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Rule 10b5-1 Arrangement Terminated [Flag]",
        "terseLabel": "Rule 10b5-1 Arrangement Terminated"
       }
      }
     },
     "auth_ref": [
      "r812"
     ]
    },
    "ifrs-full_SalesAndMarketingExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SalesAndMarketingExpense",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails": {
       "parentTag": "ifrs-full_SellingGeneralAndAdministrativeExpense",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Marketing and advertising",
        "label": "Sales and marketing expense"
       }
      }
     },
     "auth_ref": [
      "r887"
     ]
    },
    "ifrs-full_SalesFairValueMeasurementAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SalesFairValueMeasurementAssets",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Sales, fair value measurement, assets",
        "label": "Sales, fair value measurement, assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease in the fair value measurement of assets resulting from sales. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r168"
     ]
    },
    "bbplc_SalesFairValueMeasurementAssetsLiabilitiesNet": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SalesFairValueMeasurementAssetsLiabilitiesNet",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Sales, fair value measurement, assets (liabilities) net",
        "label": "Sales, Fair Value Measurement, Assets (Liabilities) Net",
        "documentation": "The decrease in the fair value measurement of assets and liabilities resulting from sales of those assets and liabilities. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_SalesFairValueMeasurementLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SalesFairValueMeasurementLiabilities",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Sales, fair value measurement, liabilities",
        "label": "Sales, fair value measurement, liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease in the fair value measurement of liabilities resulting from sales. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r168"
     ]
    },
    "bbplc_SatisfactoryBBPlusToBMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SatisfactoryBBPlusToBMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Satisfactory",
        "label": "Satisfactory BB Plus To B [Member]",
        "documentation": "This member stands for the satisfactory internal credit grade. While there is a high likelihood that the asset will be recovered and therefore, of no cause for concern to the Group, the asset may not be collateralised, or may relate to unsecured retail facilities. At the lower end of this grade there are customers that are being more carefully monitored, for example, corporate customers which are indicating some evidence of deterioration, mortgages with a high loan to value, and unsecured retail loans operating outside normal product guidelines."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ScenarioWeighting": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ScenarioWeighting",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Scenario probability weighting",
        "label": "Scenario Weighting",
        "documentation": "The scenario probability weighting, expressed as a percentage and normalised to equate to 100%. The methodology works such that the baseline (reflecting current consensus outlook) has the highest weight and the weights of adverse and favourable scenarios depend on the deviation from the baseline; the further from the baseline, the smaller the weight."
       }
      }
     },
     "auth_ref": []
    },
    "srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis",
     "presentation": [
      "http://www.home.barclays/role/AcquisitionandDisposalsofsubsidiariesDetails",
      "http://www.home.barclays/role/NetinvestmentexpenseincomeDetails",
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Investment, Name [Axis]",
        "label": "Investment, Name [Axis]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ScheduleOfShortTermEmployeeBenefitsExplanatoryTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ScheduleOfShortTermEmployeeBenefitsExplanatoryTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/StaffcostsTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of staff costs",
        "label": "Schedule Of Short-Term Employee Benefits Explanatory [Table Text Block]",
        "documentation": "The tabular disclosure of short-term employee benefits."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SchemeAsAPercentageOfTotalRetirementBenefitObligations": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SchemeAsAPercentageOfTotalRetirementBenefitObligations",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Scheme as a percentage of total retirement benefit obligations",
        "label": "Scheme As A Percentage Of Total Retirement Benefit Obligations",
        "documentation": "The scheme as a percentage of total retirement benefit obligations."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_Section75ContributionPlanMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "Section75ContributionPlanMember",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Section 75 Contribution Plan",
        "label": "Section 75 Contribution Plan [Member]",
        "documentation": "Section 75 Contribution Plan"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SecuritiesAssetBackedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SecuritiesAssetBackedMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Asset backed securities",
        "label": "Securities, Asset Backed [Member]",
        "documentation": "Securities, Asset Backed"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SecuritiesAssetsBackedMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SecuritiesAssetsBackedMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Asset backed securities",
        "label": "Securities, Assets Backed [Member]",
        "documentation": "Securities, Assets Backed"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_SecuritiesLendingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SecuritiesLendingMember",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureoftransferredfinancialassetsandtheassociatedliabilitiesDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails",
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Lending",
        "verboseLabel": "Securities lending arrangements",
        "label": "Securities lending [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the lending of securities in which the lender transfers securities in exchange for collateral provided by the borrower."
       }
      }
     },
     "auth_ref": [
      "r676",
      "r691"
     ]
    },
    "ifrs-full_SecuritisationVehiclesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SecuritisationVehiclesMember",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails",
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Securitisation vehicles",
        "verboseLabel": "Multi-seller conduit programme",
        "label": "Securitisation vehicles [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for vehicles used for the process of securitisation, whereby individual assets are pooled together and sold to a special purpose vehicle that issues debt instruments backed by the pool of assets."
       }
      }
     },
     "auth_ref": [
      "r636"
     ]
    },
    "dei_Security12bTitle": {
     "xbrltype": "securityTitleItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "Security12bTitle",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Title of 12(b) Security",
        "label": "Title of 12(b) Security",
        "documentation": "Title of a 12(b) registered security."
       }
      }
     },
     "auth_ref": [
      "r723"
     ]
    },
    "dei_SecurityExchangeName": {
     "xbrltype": "edgarExchangeCodeItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "SecurityExchangeName",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Security Exchange Name",
        "label": "Security Exchange Name",
        "documentation": "Name of the Exchange on which a security is registered."
       }
      }
     },
     "auth_ref": [
      "r725"
     ]
    },
    "ifrs-full_SegmentConsolidationItemsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SegmentConsolidationItemsAxis",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Segment consolidation items [axis]",
        "label": "Segment consolidation items [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r335"
     ]
    },
    "ifrs-full_SegmentConsolidationItemsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SegmentConsolidationItemsDomain",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Segment consolidation items [domain]",
        "label": "Segment consolidation items [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the standard value for the 'Segment consolidation items' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r341"
     ]
    },
    "ifrs-full_SegmentsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SegmentsAxis",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofgoodwillallocatedtobusinessoperationsaccordingtobusinesssegmentsDetails",
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails",
      "http://www.home.barclays/role/SegmentalreportingNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Segments [axis]",
        "label": "Segments [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r75",
      "r182",
      "r335",
      "r357",
      "r612",
      "r657"
     ]
    },
    "ifrs-full_SegmentsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SegmentsDomain",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofgoodwillallocatedtobusinessoperationsaccordingtobusinesssegmentsDetails",
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails",
      "http://www.home.barclays/role/SegmentalreportingNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Segments [domain]",
        "label": "Segments [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all segments of an entity. It also represents the standard value for the 'Segments' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r75",
      "r182",
      "r341",
      "r357",
      "r612",
      "r657"
     ]
    },
    "ifrs-full_SellingGeneralAndAdministrativeExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SellingGeneralAndAdministrativeExpense",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails": {
       "parentTag": "bbplc_InfrastructureAdministrationAndGeneralExpenses",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_OperatingExpense",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Administration and general expenses",
        "totalLabel": "Total administration and general expenses",
        "label": "Selling, general and administrative expense"
       }
      }
     },
     "auth_ref": [
      "r887"
     ]
    },
    "ifrs-full_SellingGeneralAndAdministrativeExpenseAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SellingGeneralAndAdministrativeExpenseAbstract",
     "presentation": [
      "http://www.home.barclays/role/InfrastructureadministrationandgeneralexpensesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Administration and general expenses",
        "label": "Selling, general and administrative expense [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SensitivityAnalysisForImpairmentReasonablyPossible100BpsChangeInDiscountRateAmount": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SensitivityAnalysisForImpairmentReasonablyPossible100BpsChangeInDiscountRateAmount",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "100bps increase in the discount rate",
        "label": "Sensitivity Analysis For Impairment, Reasonably Possible 100Bps Change In Discount Rate, Amount",
        "documentation": "Sensitivity Analysis For Impairment, Reasonably Possible 100Bps Change In Discount Rate, Amount"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SensitivityAnalysisForImpairmentReasonablyPossible100BpsChangeInTerminalGrowthRateAmount": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SensitivityAnalysisForImpairmentReasonablyPossible100BpsChangeInTerminalGrowthRateAmount",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "100bps decrease in terminal growth rate",
        "label": "Sensitivity Analysis For Impairment, Reasonably Possible 100Bps Change In Terminal Growth Rate, Amount",
        "documentation": "Sensitivity Analysis For Impairment, Reasonably Possible 100Bps Change In Terminal Growth Rate, Amount"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SensitivityAnalysisForImpairmentReasonablyPossible10ChangeInForecastedCashFlowsAmount": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SensitivityAnalysisForImpairmentReasonablyPossible10ChangeInForecastedCashFlowsAmount",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "10% reduction in forecasted cash flows",
        "label": "Sensitivity Analysis For Impairment, Reasonably Possible 10% Change In Forecasted Cash Flows, Amount",
        "documentation": "Sensitivity Analysis For Impairment, Reasonably Possible 10% Change In Forecasted Cash Flows, Amount"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SensitivityAnalysisForImpairmentReasonablyPossible50BpsChangeInCapitalRateAmount": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SensitivityAnalysisForImpairmentReasonablyPossible50BpsChangeInCapitalRateAmount",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "50bps increase to allocated capital rate",
        "label": "Sensitivity Analysis For Impairment, Reasonably Possible 50Bps Change In Capital Rate, Amount",
        "documentation": "Sensitivity Analysis For Impairment, Reasonably Possible 50Bps Change In Capital Rate, Amount"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SettlementsAssetsLiabilitiesOffsetAmounts": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SettlementsAssetsLiabilitiesOffsetAmounts",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Settlements assets liabilities offset amounts",
        "label": "Settlements Assets Liabilities Offset Amounts",
        "documentation": "The amount of settlements assets and liabilities offset."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_SettlementsFairValueMeasurementAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SettlementsFairValueMeasurementAssets",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Settlements, fair value measurement, assets",
        "label": "Settlements, fair value measurement, assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease in the fair value measurement of assets resulting from settlements. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r168"
     ]
    },
    "bbplc_SettlementsFairValueMeasurementAssetsLiabilitiesNet": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SettlementsFairValueMeasurementAssetsLiabilitiesNet",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Settlements, fair value measurement, assets (liabilities) net",
        "label": "Settlements, Fair Value Measurement, Assets (Liabilities) Net",
        "documentation": "The decrease in the fair value measurement of assets and liabilities resulting from settlements of those assets and liabilities. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_SettlementsFairValueMeasurementLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SettlementsFairValueMeasurementLiabilities",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Settlements, fair value measurement, liabilities",
        "label": "Settlements, fair value measurement, liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The decrease in the fair value measurement of liabilities resulting from settlements. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r168"
     ]
    },
    "bbplc_ShareBasedCompensationAndDeferredCompensationMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ShareBasedCompensationAndDeferredCompensationMember",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Share based payments and deferred compensation",
        "label": "Share-Based Compensation And Deferred Compensation [Member]",
        "documentation": "This member stands for share-based compensation arrangements and deferred compensation."
       }
      }
     },
     "auth_ref": []
    },
    "us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/us-gaap/2025",
     "localname": "ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "All Award Types",
        "terseLabel": "All Award Types"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ShareBasedPaymentVestingPeriod": {
     "xbrltype": "durationItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ShareBasedPaymentVestingPeriod",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Vesting period",
        "label": "Share-Based Payment, Vesting Period",
        "documentation": "Share-Based Payment, Vesting Period"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ShareOfOtherComprehensiveIncomeOfAssociatesAndJointVenturesAccountedForUsingEquityMethod": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ShareOfOtherComprehensiveIncomeOfAssociatesAndJointVenturesAccountedForUsingEquityMethod",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails": {
       "parentTag": "ifrs-full_ShareOfTotalComprehensiveIncomeOfAssociatesAndJointVenturesAccountedForUsingEquityMethod",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Other comprehensive income",
        "label": "Share of other comprehensive income of associates and joint ventures accounted for using equity method, net of tax"
       }
      },
      "en": {
       "role": {
        "documentation": "The entity's share of the other comprehensive income of associates and joint ventures accounted for using the equity method, net of tax. [Refer: Total for all associates [member]; Investments accounted for using equity method; Total for all joint ventures [member]; Other comprehensive income]"
       }
      }
     },
     "auth_ref": [
      "r154",
      "r598"
     ]
    },
    "ifrs-full_ShareOfProfitLossOfAssociatesAndJointVenturesAccountedForUsingEquityMethod": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ShareOfProfitLossOfAssociatesAndJointVenturesAccountedForUsingEquityMethod",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "bbplc_ProfitLossFromOperatingActivitiesBeforeImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Share of post-tax results of associates and joint ventures",
        "label": "Share of profit (loss) of associates and joint ventures accounted for using equity method"
       }
      }
     },
     "auth_ref": [
      "r333",
      "r340",
      "r595"
     ]
    },
    "ifrs-full_ShareOfProfitLossOfContinuingOperationsOfAssociatesAndJointVenturesAccountedForUsingEquityMethod": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ShareOfProfitLossOfContinuingOperationsOfAssociatesAndJointVenturesAccountedForUsingEquityMethod",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails": {
       "parentTag": "ifrs-full_ShareOfTotalComprehensiveIncomeOfAssociatesAndJointVenturesAccountedForUsingEquityMethod",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "(Loss)/Profit from continuing operations",
        "label": "Share of profit (loss) from continuing operations of associates and joint ventures accounted for using equity method"
       }
      }
     },
     "auth_ref": [
      "r153",
      "r528"
     ]
    },
    "ifrs-full_ShareOfTotalComprehensiveIncomeOfAssociatesAndJointVenturesAccountedForUsingEquityMethod": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ShareOfTotalComprehensiveIncomeOfAssociatesAndJointVenturesAccountedForUsingEquityMethod",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total comprehensive (loss)/income from continuing operations",
        "label": "Share of total comprehensive income of associates and joint ventures accounted for using equity method"
       }
      },
      "en": {
       "role": {
        "documentation": "The entity's share of the total comprehensive income of associates and joint ventures accounted for using the equity method. [Refer: Total for all associates [member]; Total for all joint ventures [member]; Investments accounted for using equity method]"
       }
      }
     },
     "auth_ref": [
      "r155"
     ]
    },
    "bbplc_ShareValuePlanDeferredShareValuePlanMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ShareValuePlanDeferredShareValuePlanMember",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Share Value Plan / Deferred Share Value Plan",
        "label": "Share Value Plan / Deferred Share Value Plan [Member]",
        "documentation": "This member stands for the deferred share value plan, which was introduced in February 2017 in addition to the Share Value Plan, which was introduced in March 2010 and approved by shareholders (for Executive Director participation and use of new issue shares) at the AGM in April 2011."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ShareValuePlanMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ShareValuePlanMember",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Share Value Plan",
        "label": "Share Value Plan [Member]",
        "documentation": "Share Value Plan"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SharesaveMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SharesaveMember",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails",
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Sharesave",
        "label": "Sharesave [member]",
        "documentation": "This member stands for the Sharesave share-based payment scheme, a principal component of Other Schemes."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ShortTermTradedInterestsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ShortTermTradedInterestsMember",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Short-term traded interests",
        "label": "Short-Term Traded Interests [Member]",
        "documentation": "This member stands for group buying and selling interests in structured entities as part of its trading activities."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ShorttermDepositsClassifiedAsCashEquivalents": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ShorttermDepositsClassifiedAsCashEquivalents",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashAndCashEquivalents",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Loans and advances to banks with original maturity of three months or less",
        "label": "Short-term deposits, classified as cash equivalents"
       }
      },
      "en": {
       "role": {
        "documentation": "A classification of cash equivalents representing short-term deposits. [Refer: Cash equivalents]"
       }
      }
     },
     "auth_ref": [
      "r868"
     ]
    },
    "ifrs-full_ShorttermEmployeeBenefitsExpenseAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ShorttermEmployeeBenefitsExpenseAbstract",
     "presentation": [
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Compensation costs",
        "label": "Short-term employee benefits expense [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_ShorttermInvestmentsClassifiedAsCashEquivalents": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ShorttermInvestmentsClassifiedAsCashEquivalents",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/Consolidatedcashflowstatement": {
       "parentTag": "ifrs-full_CashAndCashEquivalents",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedcashflowstatement",
      "http://www.home.barclays/role/ParentcompanyaccountsCashflowstatement"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Treasury and other eligible bills with original maturity of three months or less",
        "label": "Short-term investments, classified as cash equivalents"
       }
      },
      "en": {
       "role": {
        "documentation": "A classification of cash equivalents representing short-term investments. [Refer: Cash equivalents]"
       }
      }
     },
     "auth_ref": [
      "r868"
     ]
    },
    "ifrs-full_SignificantInvestmentsInAssociatesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SignificantInvestmentsInAssociatesAxis",
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails",
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Associates [axis]",
        "label": "Associates [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r65",
      "r67",
      "r159",
      "r524"
     ]
    },
    "ifrs-full_SignificantInvestmentsInAssociatesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SignificantInvestmentsInAssociatesDomain",
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresSummarisedfinancialinformationequityaccountedassociatesandjointventuresDetails",
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Associates [domain]",
        "label": "Associates [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the standard value for the 'Associates' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r65",
      "r67",
      "r159",
      "r524"
     ]
    },
    "ifrs-full_SignificantInvestmentsInSubsidiariesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SignificantInvestmentsInSubsidiariesAxis",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Subsidiaries [axis]",
        "label": "Subsidiaries [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r65",
      "r67",
      "r157",
      "r522"
     ]
    },
    "ifrs-full_SignificantInvestmentsInSubsidiariesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SignificantInvestmentsInSubsidiariesDomain",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesDisclosureofprincipalsubsidiariesDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Subsidiaries [domain]",
        "label": "Subsidiaries [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the standard value for the 'Subsidiaries' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r65",
      "r67",
      "r157",
      "r522"
     ]
    },
    "bbplc_SignificantUnobservableInputsAssetsAndLiabilities": {
     "xbrltype": "decimalItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SignificantUnobservableInputsAssetsAndLiabilities",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Significant unobservable inputs, assets and liabilities",
        "label": "Significant Unobservable Inputs, Assets And Liabilities",
        "documentation": "The value of significant unobservable input used in the measurement of the fair value of assets and liabilities."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_SocialSecurityContributions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SocialSecurityContributions",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/StaffcostsDetails": {
       "parentTag": "bbplc_StaffCompensationCosts",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Social security costs",
        "label": "Social security contributions"
       }
      }
     },
     "auth_ref": [
      "r851"
     ]
    },
    "bbplc_SpecificBasesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SpecificBasesMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Specific bases",
        "label": "Specific Bases [Member]",
        "documentation": "This member stands for macroeconomic variables used in the calculation of ECL based on specific bases."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SpreadRiskMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SpreadRiskMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Spread risk",
        "label": "Spread Risk [Member]",
        "documentation": "This member stands for the spread risk factor."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_StaffCompensationCosts": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "StaffCompensationCosts",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/StaffcostsDetails": {
       "parentTag": "ifrs-full_EmployeeBenefitsExpense",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total compensation costs",
        "label": "Staff Compensation Costs",
        "documentation": "The amount of costs relating to staff compensation."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_StandbyFacilitiesCreditLinesAndOtherCommitments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "StandbyFacilitiesCreditLinesAndOtherCommitments",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails": {
       "parentTag": "bbplc_CommitmentsGiven",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmaturityanalysisofoffbalancesheetcommitmentsgivenDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Standby facilities, credit lines and other commitments",
        "label": "Standby Facilities, Credit Lines And Other Commitments",
        "documentation": "The amount of standby facilities, credit lines and other commitments including forward starting reverse repurchase agreements."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_StandbyFacilitiesCreditLinesAndOtherCommitmentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "StandbyFacilitiesCreditLinesAndOtherCommitmentsMember",
     "presentation": [
      "http://www.home.barclays/role/ContingentliabilitiesandcommitmentsSummaryofcontingentliabilitiesandcommitmentsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Standby facilities, credit lines and other commitments",
        "label": "Standby Facilities, Credit Lines And Other Commitments [Member]",
        "documentation": "This member stands for standby facilities, credit lines and other commitments including forward starting reverse repurchase agreements."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_StatementOfCashFlowsAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "StatementOfCashFlowsAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Statement of cash flows [abstract]",
        "label": "Statement of cash flows [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_StatementOfChangesInEquityAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "StatementOfChangesInEquityAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Statement of changes in equity [abstract]",
        "label": "Statement of changes in equity [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_StatementOfChangesInEquityLineItems": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "StatementOfChangesInEquityLineItems",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequityParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Statement of changes in equity [line items]",
        "label": "Statement of changes in equity [line items]"
       }
      },
      "en": {
       "role": {
        "documentation": "Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_StatementOfChangesInEquityTable": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "StatementOfChangesInEquityTable",
     "presentation": [
      "http://www.home.barclays/role/Consolidatedstatementofchangesinequity",
      "http://www.home.barclays/role/DividendsonordinarysharesandpreferencesharesDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofcalledupsharecapitalallottedandfullypaidDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequity",
      "http://www.home.barclays/role/ParentcompanyaccountsStatementofchangesinequityParenthetical"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Statement of changes in equity [table]",
        "label": "Statement of changes in equity [table]"
       }
      },
      "en": {
       "role": {
        "documentation": "Schedule disclosing information related to changes in equity."
       }
      }
     },
     "auth_ref": [
      "r555"
     ]
    },
    "ifrs-full_StatementOfComprehensiveIncomeAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "StatementOfComprehensiveIncomeAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Statement of comprehensive income [abstract]",
        "label": "Statement of comprehensive income [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_StatementOfFinancialPositionAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "StatementOfFinancialPositionAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Statement of financial position [abstract]",
        "label": "Statement of financial position [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_StatementOfIFRSCompliance": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "StatementOfIFRSCompliance",
     "presentation": [
      "http://www.home.barclays/role/MaterialaccountingpoliciesPolicies"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Compliance with International Financial Reporting Standards",
        "label": "Statement of IFRS compliance [text block]"
       }
      }
     },
     "auth_ref": [
      "r563"
     ]
    },
    "bbplc_Sterling1000PreferenceSharesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "Sterling1000PreferenceSharesMember",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "GBP1 preference shares",
        "label": "Sterling 1,000 Preference Shares [Member]",
        "documentation": "This member stands fot the one thousand sterling cumulative callable preference shares."
       }
      }
     },
     "auth_ref": []
    },
    "ecd_StkPrcOrTsrEstimationMethodTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "StkPrcOrTsrEstimationMethodTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/ErrCompDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Stock Price or TSR Estimation Method [Text Block]",
        "terseLabel": "Stock Price or TSR Estimation Method"
       }
      }
     },
     "auth_ref": [
      "r744",
      "r755",
      "r765",
      "r798"
     ]
    },
    "us-gaap_StockAppreciationRightsSARSMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/us-gaap/2025",
     "localname": "StockAppreciationRightsSARSMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Stock Appreciation Rights (SARs) [Member]",
        "terseLabel": "Stock Appreciation Rights (SARs)"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_StressHorizonPeriodECL": {
     "xbrltype": "durationItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "StressHorizonPeriodECL",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Stress horizon period, ECL",
        "label": "Stress Horizon Period, ECL",
        "documentation": "Stress Horizon Period, ECL"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_StrongIncludingInvestmentGradeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "StrongIncludingInvestmentGradeMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Strong",
        "label": "Strong (Including Investment Grade) [Member]",
        "documentation": "This member stands for the strong internal credit grade including investment grade. There is a very high likelihood of the asset being recovered in full."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_StructuralCurrencyExposureBeforeHedgingInstruments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "StructuralCurrencyExposureBeforeHedgingInstruments",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails": {
       "parentTag": "bbplc_StructuralCurrencyExposureNetOfHedgingInstruments",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Structural currency exposures pre- economic hedges",
        "label": "Structural Currency Exposure, Before Hedging Instruments",
        "documentation": "The amount of structural currency exposures which are before economic hedges."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_StructuralCurrencyExposureNetOfHedgingInstruments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "StructuralCurrencyExposureNetOfHedgingInstruments",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Remaining structural currency exposures",
        "label": "Structural Currency Exposure, Net Of Hedging Instruments",
        "documentation": "The amount of structural currency exposures net of hedging instruments."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_StructuralCurrencyExposureOtherEquityInstruments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "StructuralCurrencyExposureOtherEquityInstruments",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails": {
       "parentTag": "bbplc_StructuralCurrencyExposureNetOfHedgingInstruments",
       "weight": -1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Other Equity instruments",
        "label": "Structural Currency Exposure, Other Equity Instruments",
        "documentation": "Structural Currency Exposure, Other Equity Instruments"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SubordinatedFloatingRateNotesDue2040Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SubordinatedFloatingRateNotesDue2040Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Subordinated Floating Rate Notes (EUR 68m)",
        "label": "Subordinated Floating Rate Notes, Due 2040 [Member]",
        "documentation": "This member stands for the Subordinated Floating Rate Notes (EUR 68m) maturing in 2040, denominated in Euro currency."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SubordinatedFloatingRateNotesDue2047Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SubordinatedFloatingRateNotesDue2047Member",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Floating Rate Subordinated Notes (USD 456m)",
        "label": "Subordinated Floating Rate Notes, Due 2047 [Member]",
        "documentation": "This member stands for the Subordinated Notes, maturing in 2047 and denominated in United States of America, Dollars currency."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_SubordinatedLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SubordinatedLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_FinancialLiabilities",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails": {
       "parentTag": "ifrs-full_FinancialLiabilitiesAtFairValueThroughProfitOrLossDesignatedAsUponInitialRecognition",
       "weight": 1.0,
       "order": 4.0
      },
      "http://www.home.barclays/role/Consolidatedbalancesheet": {
       "parentTag": "ifrs-full_Liabilities",
       "weight": 1.0,
       "order": 6.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedbalancesheet",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofcomparisonofcarryingamountsandfairvaluesforassetsandliabilitiesnotheldatfairvalueDetails",
      "http://www.home.barclays/role/FinancialliabilitiesdesignatedatfairvalueDisclosureoffinancialliabilitiesdesignatedatfairvalueDetails",
      "http://www.home.barclays/role/Parentcompanyaccountsbalancesheet",
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Subordinated liabilities",
        "verboseLabel": "Subordinated debt",
        "negatedLabel": "Subordinated liabilities",
        "periodStartLabel": "Subordinated liabilities, opening balance",
        "periodEndLabel": "Subordinated liabilities, closing balance",
        "label": "Subordinated liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of liabilities that are subordinate to other liabilities with respect to claims."
       }
      }
     },
     "auth_ref": [
      "r883"
     ]
    },
    "ifrs-full_SubordinatedLiabilitiesAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SubordinatedLiabilitiesAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Subordinated liabilities [abstract]",
        "label": "Subordinated liabilities [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SubordinatedLiabilitiesIncludingThoseDesignatedAtFairValue": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SubordinatedLiabilitiesIncludingThoseDesignatedAtFairValue",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedanddatedsubordinatedliabilitiesDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedanddatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total subordinated liabilities",
        "totalLabel": "Total subordinated liabilities",
        "label": "Subordinated Liabilities, Including Those Designated At Fair Value",
        "documentation": "Subordinated Liabilities, Including Those Designated At Fair Value"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SubordinatedLiabilitiesLoansIssuedIntraGroupFromBarclaysPLCMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SubordinatedLiabilitiesLoansIssuedIntraGroupFromBarclaysPLCMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Bank PLC loans issued intra-group to Barclays PLC",
        "label": "Subordinated Liabilities, Loans Issued Intra-Group From Barclays PLC [Member]",
        "documentation": "This member stands for subordinated liabilities, loans issued intra-group by parent, Barclays Bank PLC to ultimate parent of group, Barclays PLC."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SubordinatedLiabilitiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SubordinatedLiabilitiesMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Subordinated liabilities",
        "label": "Subordinated Liabilities [Member]",
        "documentation": "This member stands for the subordinated debt is measured at amortised cost using the effective interest method under IFRS 9."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SubordinatedLiabilitiesUndiscountedCashFlows": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SubordinatedLiabilitiesUndiscountedCashFlows",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails": {
       "parentTag": "bbplc_TotalFinancialLiabilitiesUndiscounted",
       "weight": 1.0,
       "order": 10.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Subordinated liabilities, undiscounted",
        "label": "Subordinated Liabilities, Undiscounted Cash Flows",
        "documentation": "The amount of contractual undiscounted cash flows in relation to subordinated liabilities."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_SubsequentToDecember152034Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SubsequentToDecember152034Member",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Subsequent to December 15, 2034",
        "label": "Subsequent To December 15, 2034 [Member]",
        "documentation": "Subsequent To December 15, 2034"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_SubsidiariesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SubsidiariesMember",
     "presentation": [
      "http://www.home.barclays/role/AuditorsremunerationDisclosureofAuditorsremunerationDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total for all subsidiaries",
        "label": "Total for all subsidiaries [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for entities that are controlled by another entity."
       }
      }
     },
     "auth_ref": [
      "r54",
      "r65",
      "r67",
      "r157",
      "r424",
      "r522"
     ]
    },
    "bbplc_SummarisedFinancialInformationAssociatesAndJointVenturesTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SummarisedFinancialInformationAssociatesAndJointVenturesTableTextBlock",
     "presentation": [
      "http://www.home.barclays/role/InvestmentsinassociatesandjointventuresTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Summarised financial information, equity accounted associates and joint ventures",
        "label": "Summarised Financial Information Associates And Joint Ventures [Table Text Block]",
        "documentation": "The disclosure of detailed information on equity accounted associates and joint ventures."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_SummaryQuantitativeDataAboutEntitysExposureToRisk": {
     "xbrltype": "textBlockItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SummaryQuantitativeDataAboutEntitysExposureToRisk",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementTables"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Disclosure of maximum exposure and effects of collateral and other credit enhancements",
        "label": "Summary quantitative data about entity's exposure to risk [text block]"
       }
      },
      "en": {
       "role": {
        "documentation": "The disclosure of summary quantitative data about the entity's exposure to risks arising from financial instruments. This disclosure shall be based on the information provided internally to key management personnel of the entity, for example, the entity\u2019s board of directors or chief executive officer. [Refer: Classes of financial instruments [domain]; Key management personnel of entity or parent [member]]"
       }
      }
     },
     "auth_ref": [
      "r278"
     ]
    },
    "bbplc_SurchargeRateUKBanking": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "SurchargeRateUKBanking",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "UK banking surcharge rate (%)",
        "label": "Surcharge Rate, UK Banking",
        "documentation": "Surcharge Rate, UK Banking"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_SurplusDeficitInPlan": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "SurplusDeficitInPlan",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofbalancesheetreconciliationDetails",
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Surplus in plan",
        "totalLabel": "Net surplus",
        "label": "Surplus (deficit) in plan"
       }
      },
      "en": {
       "role": {
        "documentation": "The fair value of any plan assets, less the present value of the defined benefit obligation. [Refer: Plan assets [member]]"
       }
      }
     },
     "auth_ref": [
      "r849"
     ]
    },
    "ecd_TabularListTableTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "TabularListTableTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Tabular List [Table Text Block]",
        "terseLabel": "Tabular List, Table"
       }
      }
     },
     "auth_ref": [
      "r791"
     ]
    },
    "bbplc_TangibleEquity": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TangibleEquity",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails": {
       "parentTag": "ifrs-full_IntangibleAssetsAndGoodwill",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureoftheoutcometheimpairmentreviewDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Tangible equity",
        "label": "Tangible Equity",
        "documentation": "Tangible Equity"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TaxEffectFromChangeInTaxRate": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TaxEffectFromChangeInTaxRate",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 10.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Tax relief on payments made under AT1 instruments",
        "label": "Tax effect from change in tax rate"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to changes in the tax rate. [Refer: Accounting profit]"
       }
      }
     },
     "auth_ref": [
      "r4",
      "r392"
     ]
    },
    "bbplc_TaxEffectNonDeductibleImpairmentsAndLossesOnDivestments": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxEffectNonDeductibleImpairmentsAndLossesOnDivestments",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 14.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-deductible impairments and losses on divestments",
        "label": "Tax Effect Non-Deductible Impairments And Losses On Divestments",
        "documentation": "Tax Effect Non-Deductible Impairments And Losses On Divestments"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TaxEffectNonDeductibleProvisionsForInvestigationsAndLitigation": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxEffectNonDeductibleProvisionsForInvestigationsAndLitigation",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 13.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-deductible provisions for investigations and litigation",
        "label": "Tax Effect Non-Deductible Provisions For Investigations And Litigation",
        "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to non-deductible provisions for investigations and litigation. [Refer: Accounting profit]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TaxEffectNonDeductibleProvisionsForUKCustomerRedress": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxEffectNonDeductibleProvisionsForUKCustomerRedress",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 12.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-deductible provisions for UK customer redress",
        "label": "Tax Effect Non-Deductible Provisions For UK Customer Redress",
        "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to non-deductible provisionsfor UK customer redress. . [Refer: Accounting profit]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TaxEffectOfChangesInRecognitionOfDeferredTaxAndUnrecognisedTaxLossesAndUK": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxEffectOfChangesInRecognitionOfDeferredTaxAndUnrecognisedTaxLossesAndUK",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Changes in recognition of deferred tax and effect of unrecognised tax losses",
        "label": "Tax Effect Of Changes in Recognition of Deferred Tax and Unrecognised Tax Losses And UK",
        "documentation": "Tax Effect Of Changes in Recognition of Deferred Tax and Unrecognised Tax Losses And UK"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TaxEffectOfExpenseNotDeductibleInDeterminingTaxableProfitTaxLoss": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TaxEffectOfExpenseNotDeductibleInDeterminingTaxableProfitTaxLoss",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 7.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-deductible expenses",
        "label": "Tax effect of expense not deductible in determining taxable profit (tax loss)"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to expenses not deductible in determining taxable profit (tax loss). [Refer: Accounting profit]"
       }
      }
     },
     "auth_ref": [
      "r4",
      "r392"
     ]
    },
    "ifrs-full_TaxEffectOfForeignTaxRates": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TaxEffectOfForeignTaxRates",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Impact of profits/losses earned in territories with different statutory rates to the UK (weighted average tax rate is 23.5% (2024: 23%, 2023: 23.6%))",
        "label": "Tax effect of foreign tax rates"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to foreign tax rates. [Refer: Accounting profit]"
       }
      }
     },
     "auth_ref": [
      "r4",
      "r392"
     ]
    },
    "bbplc_TaxEffectOfNonCreditableTaxesIncludingWithholdingTaxes": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxEffectOfNonCreditableTaxesIncludingWithholdingTaxes",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-creditable taxes including withholding taxes",
        "label": "Tax Effect Of Non-Creditable Taxes Including Withholding Taxes",
        "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to non-creditable expenses including withholding taxes. [Refer: Accounting profit]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TaxEffectOfRevenuesExemptFromTaxation2011": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TaxEffectOfRevenuesExemptFromTaxation2011",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": -1.0,
       "order": 8.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Non-taxable gains and income",
        "label": "Tax effect of revenues exempt from taxation"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to revenues that are exempt from taxation. [Refer: Accounting profit]"
       }
      }
     },
     "auth_ref": [
      "r4",
      "r392"
     ]
    },
    "bbplc_TaxEffectOfTaxCreditInflationLinkedGovernmentBondsHoldings": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxEffectOfTaxCreditInflationLinkedGovernmentBondsHoldings",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": -1.0,
       "order": 11.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Tax relief on holdings of inflation-linked government bonds",
        "label": "Tax Effect Of Tax Credit, Inflation Linked Government Bonds Holdings",
        "documentation": "Tax Effect Of Tax Credit, Inflation Linked Government Bonds Holdings"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TaxEffectOfUKBankLevyBeingNonDeductible": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxEffectOfUKBankLevyBeingNonDeductible",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 6.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Impact of UK bank levy being non-deductible",
        "label": "Tax Effect Of UK Bank Levy Being Non-Deductible",
        "documentation": "The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to the United Kingdom Bank levy being non-deductible. The BRRD requires EU member states to establish a pre-funded resolution financing arrangement with funding equal to 1% of covered deposits by 31 December 2024 to cover the costs of bank resolutions. Where the amount of such pre-funding is insufficient, the BRRD requires that EU member states raise subsequent contributions. The UK government raises both pre-funded and subsequent contributions that would be required were the pre-funded contributions not to cover costs or other expenses incurred by use of the resolution funds by way of a tax on the balance sheets of banks."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TaxExpenseIncomeAtApplicableTaxRate": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TaxExpenseIncomeAtApplicableTaxRate",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_IncomeTaxExpenseContinuingOperations",
       "weight": 1.0,
       "order": 1.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Tax charge based on the applicable UK corporation tax rate of 25% (2024: 25%, 2023: 23.5%)",
        "label": "Tax expense (income) at applicable tax rate"
       }
      },
      "en": {
       "role": {
        "documentation": "The product of the accounting profit multiplied by the applicable tax rate(s). [Refer: Accounting profit; Applicable tax rate]"
       }
      }
     },
     "auth_ref": [
      "r4",
      "r392"
     ]
    },
    "ifrs-full_TaxRateEffectFromChangeInTaxRate": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TaxRateEffectFromChangeInTaxRate",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": 1.0,
       "order": 10.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Tax relief on payments made under AT1 instruments, percentage",
        "label": "Tax rate effect from change in tax rate"
       }
      },
      "en": {
       "role": {
        "documentation": "The tax rate effect on the reconciliation between the average effective tax rate and the applicable tax rate resulting from a change in tax rate. [Refer: Average effective tax rate; Applicable tax rate]"
       }
      }
     },
     "auth_ref": [
      "r5",
      "r393"
     ]
    },
    "bbplc_TaxRateEffectNonDeductibleImpairmentsAndLossesOnDivestments": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxRateEffectNonDeductibleImpairmentsAndLossesOnDivestments",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": 1.0,
       "order": 14.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-deductible impairments and losses on divestments, percentage",
        "label": "Tax Rate Effect Non-Deductible Impairments And Losses On Divestments",
        "documentation": "Tax Rate Effect Non-Deductible Impairments And Losses On Divestments"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TaxRateEffectNonDeductibleProvisionsForInvestigationsAndLitigation": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxRateEffectNonDeductibleProvisionsForInvestigationsAndLitigation",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": 1.0,
       "order": 13.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-deductible provisions for investigations and litigation, percentage",
        "label": "Tax Rate Effect Non-Deductible Provisions For Investigations And Litigation",
        "documentation": "The tax rate effect on the reconciliation between the average effective tax rate and the applicable tax rate resulting from non-deductible provisions for investigations and litigation. [Refer: Average effective tax rate; Applicable tax rate]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TaxRateEffectNonDeductibleProvisionsForUKCustomerRedress": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxRateEffectNonDeductibleProvisionsForUKCustomerRedress",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": 1.0,
       "order": 12.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-deductible provisions for UK customer redress, percentage",
        "label": "Tax Rate Effect Non-Deductible Provisions For UK Customer Redress",
        "documentation": "The tax rate effect on the reconciliation between the average effective tax rate and the applicable tax rate resulting from non-deductible provisionsfor UK customer redress. [Refer: Average effective tax rate; Applicable tax rate]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TaxRateEffectOfChangesInRecognitionOfDeferredTaxAndUnrecognisedTaxLossesAndUK": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxRateEffectOfChangesInRecognitionOfDeferredTaxAndUnrecognisedTaxLossesAndUK",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": 1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Changes in recognition of deferred tax and effect of unrecognised tax losses, percentage",
        "label": "Tax Rate Effect Of Changes in Recognition of Deferred Tax and Unrecognised Tax Losses And UK",
        "documentation": "Tax Rate Effect Of Changes in Recognition of Deferred Tax and Unrecognised Tax Losses And UK"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TaxRateEffectOfExpenseNotDeductibleInDeterminingTaxableProfitTaxLoss": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TaxRateEffectOfExpenseNotDeductibleInDeterminingTaxableProfitTaxLoss",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": 1.0,
       "order": 7.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-deductible expenses, percentage",
        "label": "Tax rate effect of expense not deductible in determining taxable profit (tax loss)"
       }
      },
      "en": {
       "role": {
        "documentation": "The tax rate effect on the reconciliation between the average effective tax rate and the applicable tax rate resulting from the expenses not deductible in determining taxable profit. [Refer: Average effective tax rate; Applicable tax rate]"
       }
      }
     },
     "auth_ref": [
      "r5",
      "r393"
     ]
    },
    "ifrs-full_TaxRateEffectOfForeignTaxRates": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TaxRateEffectOfForeignTaxRates",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Tax rate impact of profits/losses earned in territories with different statutory rates to the UK",
        "label": "Tax rate effect of foreign tax rates"
       }
      },
      "en": {
       "role": {
        "documentation": "The tax rate effect on the reconciliation between the average effective tax rate and the applicable tax rate resulting from the application of foreign tax rates. [Refer: Average effective tax rate; Applicable tax rate]"
       }
      }
     },
     "auth_ref": [
      "r5",
      "r393"
     ]
    },
    "bbplc_TaxRateEffectOfNonCreditableTaxesIncludingWithholdingTaxes": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxRateEffectOfNonCreditableTaxesIncludingWithholdingTaxes",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Non-creditable taxes including withholding taxes, percentage",
        "label": "Tax Rate Effect Of Non-Creditable Taxes Including Withholding Taxes",
        "documentation": "The tax rate effect on the reconciliation between the average effective tax rate and the applicable tax rate resulting from the United Kingdom Bank levy being non-deductible. [Refer: Average effective tax rate; Applicable tax rate]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TaxRateEffectOfRevenuesExemptFromTaxation": {
     "xbrltype": "percentItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TaxRateEffectOfRevenuesExemptFromTaxation",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": -1.0,
       "order": 8.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Non-taxable gains and income, percentage",
        "label": "Tax rate effect of revenues exempt from taxation"
       }
      },
      "en": {
       "role": {
        "documentation": "The tax rate effect on the reconciliation between the average effective tax rate and the applicable tax rate resulting from revenue that is exempt from taxation. [Refer: Average effective tax rate; Applicable tax rate]"
       }
      }
     },
     "auth_ref": [
      "r5",
      "r393"
     ]
    },
    "bbplc_TaxRateEffectOfTaxCreditInflationLinkedGovernmentBondsHoldings": {
     "xbrltype": "pureItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxRateEffectOfTaxCreditInflationLinkedGovernmentBondsHoldings",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": -1.0,
       "order": 11.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Tax relief on holdings of inflation-linked government bonds, percentage",
        "label": "Tax Rate Effect Of Tax Credit, Inflation Linked Government Bonds Holdings",
        "documentation": "Tax Rate Effect Of Tax Credit, Inflation Linked Government Bonds Holdings"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TaxRateEffectOfUKBankLevyBeingNonDeductible": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TaxRateEffectOfUKBankLevyBeingNonDeductible",
     "calculation": {
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails": {
       "parentTag": "ifrs-full_AverageEffectiveTaxRate",
       "weight": 1.0,
       "order": 6.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Impact of UK bank levy being non-deductible, percentage",
        "label": "Tax Rate Effect Of UK Bank Levy Being Non-Deductible",
        "documentation": "The tax rate effect on the reconciliation between the average effective tax rate and the applicable tax rate resulting from the United Kingdom Bank levy being non-deductible. The BRRD requires EU member states to establish a pre-funded resolution financing arrangement with funding equal to 1% of covered deposits by 31 December 2024 to cover the costs of bank resolutions. Where the amount of such pre-funding is insufficient, the BRRD requires that EU member states raise subsequent contributions. The UK government raises both pre-funded and subsequent contributions that would be required were the pre-funded contributions not to cover costs or other expenses incurred by use of the resolution funds by way of a tax on the balance sheets of banks."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TemporaryDifferenceMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TemporaryDifferenceMember",
     "presentation": [
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Temporary differences",
        "label": "Temporary differences [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for differences between the carrying amount of an asset or liability in the statement of financial position and its tax base. Temporary differences may be either: (a) taxable temporary differences; or (b) deductible temporary differences. [Refer: Carrying amount [member]]"
       }
      }
     },
     "auth_ref": [
      "r10",
      "r397"
     ]
    },
    "ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Temporary difference, unused tax losses and unused tax credits [axis]",
        "label": "Temporary difference, unused tax losses and unused tax credits [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r10",
      "r397"
     ]
    },
    "ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Temporary difference, unused tax losses and unused tax credits [domain]",
        "label": "Temporary difference, unused tax losses and unused tax credits [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for temporary differences, unused tax losses and unused tax credits. It also represents the standard value for the 'Temporary difference, unused tax losses and unused tax credits' axis if no other member is used. [Refer: Temporary differences [member]; Unused tax credits [member]; Unused tax losses [member]]"
       }
      }
     },
     "auth_ref": [
      "r10",
      "r397"
     ]
    },
    "ifrs-full_TemporaryDifferencesAssociatedWithInvestmentsInSubsidiariesBranchesAndAssociatesAndInterestsInJointVentures": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TemporaryDifferencesAssociatedWithInvestmentsInSubsidiariesBranchesAndAssociatesAndInterestsInJointVentures",
     "presentation": [
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Temporary differences associated with investments in related entities for which deferred tax liabilities have not been recognised",
        "label": "Temporary differences associated with investments in subsidiaries, branches and associates and interests in joint arrangements for which deferred tax liabilities have not been recognised"
       }
      },
      "en": {
       "role": {
        "documentation": "The aggregate amount of temporary differences associated with investments in subsidiaries, branches and associates and interests in joint arrangements, for which deferred tax liabilities have not been recognised as a result of satisfying both of the following conditions: (a) the parent, investor, joint venturer or joint operator is able to control the timing of the reversal of the temporary difference; and (b) it is probable that the temporary difference will not reverse in the foreseeable future. [Refer: Total for all associates [member]; Total for all subsidiaries [member]; Temporary differences [member]; Investments in subsidiaries reported in separate financial statements]"
       }
      }
     },
     "auth_ref": [
      "r7"
     ]
    },
    "bbplc_TemporaryStaffCosts": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TemporaryStaffCosts",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/StaffcostsDetails": {
       "parentTag": "bbplc_ResourcingCosts",
       "weight": 1.0,
       "order": 3.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Temporary staff costs",
        "label": "Temporary Staff Costs",
        "documentation": "The amount of costs relating to temporary staff costs."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TermAtWhichScenarioConvergesToSteadyState": {
     "xbrltype": "durationItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TermAtWhichScenarioConvergesToSteadyState",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Term at which scenario converges to steady state",
        "label": "Term At Which Scenario Converges To Steady State",
        "documentation": "The term all five scenarios of model to calculate expected credit losses converge to a steady state."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ThirdPartiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ThirdPartiesMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Third parties",
        "label": "Third Parties [Member]",
        "documentation": "This member stands for third parties."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_ThroughDecember152034Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "ThroughDecember152034Member",
     "presentation": [
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Through December 15, 2034",
        "label": "Through December 15, 2034 [Member]",
        "documentation": "Through December 15, 2034"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TierTwoCapitalInstrumentsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TierTwoCapitalInstrumentsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcapitalresourcesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Total regulatory capital",
        "label": "Tier Two Capital Instruments [member]",
        "documentation": "This member stands for the tier 2 (T2) captial instruments of the entity."
       }
      }
     },
     "auth_ref": []
    },
    "srt_TitleOfIndividualAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "TitleOfIndividualAxis",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Title and Position [Axis]",
        "label": "Title and Position [Axis]"
       }
      }
     },
     "auth_ref": []
    },
    "srt_TitleOfIndividualWithRelationshipToEntityDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://fasb.org/srt/2025",
     "localname": "TitleOfIndividualWithRelationshipToEntityDomain",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Title and Position [Domain]",
        "label": "Title and Position [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TopOfRangeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TopOfRangeMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsNarrativeDetails",
      "http://www.home.barclays/role/PropertyplantandequipmentDisclosureofdepreciationratesDetails",
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofactuarialvaluationofschemesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails",
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "High",
        "verboseLabel": "Top of range",
        "netLabel": "Max",
        "label": "Top of range [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for top of a range."
       }
      }
     },
     "auth_ref": [
      "r127",
      "r177",
      "r202",
      "r222",
      "r386",
      "r649",
      "r651",
      "r875"
     ]
    },
    "bbplc_TotalFinancialLiabilitiesUndiscounted": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TotalFinancialLiabilitiesUndiscounted",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails": {
       "parentTag": null,
       "weight": null,
       "order": null,
       "root": true
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofcontractualmaturityoffinancialliabilitiesundiscountedDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "totalLabel": "Total financial liabilities, undiscounted cash flows",
        "label": "Total Financial Liabilities, Undiscounted",
        "documentation": "The amount of contractual undiscounted cash flows in relation to financial liabilities."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TotalNumberOfEconomicScenariosToCalculateECL": {
     "xbrltype": "integerItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TotalNumberOfEconomicScenariosToCalculateECL",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of economic scenarios",
        "label": "Total Number Of Economic Scenarios To Calculate ECL",
        "documentation": "Total Number Of Economic Scenarios To Calculate ECL"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TotalNumberOfEconomicScenariosToCalculateECLAsAPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TotalNumberOfEconomicScenariosToCalculateECLAsAPercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Number of economic scenarios, percentage",
        "label": "Total Number Of Economic Scenarios To Calculate ECL, As A Percentage",
        "documentation": "Total Number Of Economic Scenarios To Calculate ECL, As A Percentage"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_TotalShareholderRtnAmt": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "TotalShareholderRtnAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Total Shareholder Return Amount",
        "terseLabel": "Total Shareholder Return Amount"
       }
      }
     },
     "auth_ref": [
      "r783"
     ]
    },
    "ecd_TotalShareholderRtnVsPeerGroupTextBlock": {
     "xbrltype": "textBlockItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "TotalShareholderRtnVsPeerGroupTextBlock",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Total Shareholder Return Vs Peer Group [Text Block]",
        "terseLabel": "Total Shareholder Return Vs Peer Group"
       }
      }
     },
     "auth_ref": [
      "r790"
     ]
    },
    "ifrs-full_TradeReceivablesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TradeReceivablesMember",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofcarryingamountoftheassetspledgedassecurityagainstliabilitiesDetails",
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesDisclosureofcreditimpairmentchargesandotherprovisionsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Trade receivables",
        "terseLabel": "Cash collateral",
        "label": "Trade receivables [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for trade receivables. [Refer: Trade receivables]"
       }
      }
     },
     "auth_ref": [
      "r283",
      "r294",
      "r509",
      "r515",
      "r669",
      "r880"
     ]
    },
    "bbplc_TradedDerivativesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TradedDerivativesMember",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Traded derivatives",
        "label": "Traded Derivatives [Member]",
        "documentation": "This member stands for the traded derivatives within structured entities."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TradedLoansMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TradedLoansMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofBalanceSheetcreditqualityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/TradingportfolioDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Traded loans",
        "label": "Traded Loans [Member]",
        "documentation": "This member stands for traded loans."
       }
      }
     },
     "auth_ref": []
    },
    "ecd_TradingArrAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "TradingArrAxis",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Trading Arrangement [Axis]",
        "terseLabel": "Trading Arrangement:"
       }
      }
     },
     "auth_ref": [
      "r811"
     ]
    },
    "ecd_TradingArrByIndTable": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "TradingArrByIndTable",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Trading Arrangements, by Individual [Table]",
        "terseLabel": "Trading Arrangements, by Individual"
       }
      }
     },
     "auth_ref": [
      "r813"
     ]
    },
    "ifrs-full_TradingEquitySecuritiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TradingEquitySecuritiesMember",
     "presentation": [
      "http://www.home.barclays/role/TradingportfolioDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Equity securities",
        "label": "Trading equity securities [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for equity instruments that (a) are acquired or incurred principally for the purpose of selling or repurchasing it in the near term; or (b) on initial recognition are part of a portfolio of identified financial instruments that are managed together and for which there is evidence of a recent actual pattern of short-term profit-taking."
       }
      }
     },
     "auth_ref": [
      "r640",
      "r650"
     ]
    },
    "ifrs-full_TradingIncomeExpense": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TradingIncomeExpense",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails": {
       "parentTag": "ifrs-full_GainsLossesRecognisedInProfitOrLossAttributableToChangeInUnrealisedGainsOrLossesForAssetsHeldAtEndOfPeriodFairValueMeasurement",
       "weight": 1.0,
       "order": 1.0
      },
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "bbplc_OperatingIncome",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofunrealisedgainsandlossesonLevel3financialassetsandliabilitiesDetails",
      "http://www.home.barclays/role/NettradingincomeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net trading income",
        "verboseLabel": "Trading income",
        "label": "Trading income (expense)"
       }
      }
     },
     "auth_ref": [
      "r887"
     ]
    },
    "ifrs-full_TradingIncomeExpenseAbstract": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TradingIncomeExpenseAbstract",
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Trading income (expense) [abstract]",
        "label": "Trading income (expense) [abstract]"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TradingIncomeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TradingIncomeMember",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Recycled to net trading income",
        "label": "Trading Income [Member]",
        "documentation": "Trading Income"
       }
      }
     },
     "auth_ref": []
    },
    "dei_TradingSymbol": {
     "xbrltype": "tradingSymbolItemType",
     "nsuri": "http://xbrl.sec.gov/dei/2025",
     "localname": "TradingSymbol",
     "presentation": [
      "http://www.home.barclays/role/Cover"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Trading Symbol",
        "label": "Trading Symbol",
        "documentation": "Trading symbol of an instrument as listed on an exchange."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TransactionalBankingServicesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TransactionalBankingServicesMember",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Transactional",
        "label": "Transactional Banking Services [Member]",
        "documentation": "This member stands for fees fees from service charges on deposit account, cash management services and transactional processing fees. These fees include such items as ATM fees, wire transfer fees, balance transfer fees, overdraft or late fees and foreign exchange fees, among others."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TransfersExposureToCreditRisk": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TransfersExposureToCreditRisk",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails": {
       "parentTag": "bbplc_NetExposureToCreditRisk",
       "weight": -1.0,
       "order": 5.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Risk transfer",
        "label": "Transfers Exposure To Credit Risk",
        "documentation": "The amount of transfers for exposure to credit risk."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TransfersFromStage1ToStage2Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TransfersFromStage1ToStage2Member",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Transfers from Stage 1 to Stage 2",
        "label": "Transfers From Stage 1 To Stage 2 [Member]",
        "documentation": "This member stands for the transfers of financial assets from stage 1 to stage 2."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TransfersFromStage2ToStage1Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TransfersFromStage2ToStage1Member",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Transfers from Stage 2 to Stage 1",
        "label": "Transfers From Stage 2 To Stage 1 [Member]",
        "documentation": "This member stands for the transfers of financial assets from stage 2 to stage 1"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TransfersFromStage3Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TransfersFromStage3Member",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Transfers from Stage 3",
        "label": "Transfers From Stage 3 [Member]",
        "documentation": "This member stands for the transfers of financial assets from stage 3 credit impaired."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TransfersIntoLevel3OfFairValueHierarchyAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TransfersIntoLevel3OfFairValueHierarchyAssets",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets transferred into level 3",
        "label": "Transfers into Level 3 of fair value hierarchy, assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of transfers of assets into Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]]"
       }
      }
     },
     "auth_ref": [
      "r169"
     ]
    },
    "bbplc_TransfersIntoLevel3OfFairValueHierarchyAssetsLiabilitiesNet": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TransfersIntoLevel3OfFairValueHierarchyAssetsLiabilitiesNet",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Transfers into Level 3 of fair value hierarchy, assets (liabilities) net",
        "label": "Transfers Into Level 3 Of Fair Value Hierarchy, Assets (Liabilities) Net",
        "documentation": "The amount of transfers of assets less liabilities into Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TransfersIntoLevel3OfFairValueHierarchyLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TransfersIntoLevel3OfFairValueHierarchyLiabilities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Liabilities transferred into level 3",
        "negatedLabel": "Transfers into Level 3 of fair value hierarchy, liabilities",
        "label": "Transfers into Level 3 of fair value hierarchy, liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of transfers of liabilities into Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]]"
       }
      }
     },
     "auth_ref": [
      "r169"
     ]
    },
    "bbplc_TransfersOutOfLevel1IntoLevel2Or3FairValueHierarchyAssetsHeldAtEndOfReportingPeriod": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TransfersOutOfLevel1IntoLevel2Or3FairValueHierarchyAssetsHeldAtEndOfReportingPeriod",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets re-classification from quoted to unquoted",
        "label": "Transfers Out Of Level 1 Into Level 2 Or 3 Fair Value Hierarchy, Assets Held At End Of Reporting Period",
        "documentation": "Transfers Out Of Level 1 Into Level 2 Or 3 Fair Value Hierarchy, Assets Held At End Of Reporting Period"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyAssets",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Asset transfers from level 2 to level 1",
        "label": "Transfers out of Level 2 into Level 1 of fair value hierarchy, assets held at end of reporting period"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of transfers out of Level 2 and into Level 1 of the fair value hierarchy of assets held at the end of the reporting period. [Refer: Level 1 of fair value hierarchy [member]; Level 2 of fair value hierarchy [member]]"
       }
      }
     },
     "auth_ref": [
      "r164"
     ]
    },
    "ifrs-full_TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TransfersOutOfLevel2IntoLevel1OfFairValueHierarchyLiabilities",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "Liability transfers from level 2 to level 1",
        "label": "Transfers out of Level 2 into Level 1 of fair value hierarchy, liabilities held at end of reporting period"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of transfers out of Level 2 and into Level 1 of the fair value hierarchy of liabilities held at the end of the reporting period. [Refer: Level 1 of fair value hierarchy [member]; Level 2 of fair value hierarchy [member]]"
       }
      }
     },
     "auth_ref": [
      "r164"
     ]
    },
    "bbplc_TransfersOutOfLevel2Or3IntoLevel1FairValueHierarchyAssetsHeldAtEndOfReportingPeriod": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TransfersOutOfLevel2Or3IntoLevel1FairValueHierarchyAssetsHeldAtEndOfReportingPeriod",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsDisclosureofanalysisofschemeassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Assets re-classification from unquoted to quoted",
        "label": "Transfers Out Of Level 2 Or 3 Into Level 1 Fair Value Hierarchy, Assets Held At End Of Reporting Period",
        "documentation": "Transfers Out Of Level 2 Or 3 Into Level 1 Fair Value Hierarchy, Assets Held At End Of Reporting Period"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TransfersOutOfLevel3OfFairValueHierarchyAssets": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TransfersOutOfLevel3OfFairValueHierarchyAssets",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Transfers out of Level 3 of fair value hierarchy, assets",
        "label": "Transfers out of Level 3 of fair value hierarchy, assets"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of transfers of assets out of Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]]"
       }
      }
     },
     "auth_ref": [
      "r169"
     ]
    },
    "bbplc_TransfersOutOfLevel3OfFairValueHierarchyAssetsLiabilitiesNet": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TransfersOutOfLevel3OfFairValueHierarchyAssetsLiabilitiesNet",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Transfers out of Level 3 of fair value hierarchy, assets (liabilities) net",
        "label": "Transfers Out Of Level 3 Of Fair Value Hierarchy, Assets (Liabilities) Net",
        "documentation": "The amount of transfers of assets less liabilities out of Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TransfersOutOfLevel3OfFairValueHierarchyLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TransfersOutOfLevel3OfFairValueHierarchyLiabilities",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofanalysisofmovementsinLevel3assetsandliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Transfers out of Level 3 of fair value hierarchy, liabilities",
        "label": "Transfers out of Level 3 of fair value hierarchy, liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of transfers of liabilities out of Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]]"
       }
      }
     },
     "auth_ref": [
      "r169"
     ]
    },
    "bbplc_TransfersOutOfTheFundAndContributionRefunds": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TransfersOutOfTheFundAndContributionRefunds",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Transfers out of the fund and contribution refunds",
        "label": "Transfers Out Of The Fund And Contribution Refunds",
        "documentation": "Transfers out of the fund and contribution refunds pertaining to defined pension plans."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TransfersToStage3Member": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TransfersToStage3Member",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Transfers to Stage 3",
        "label": "Transfers To Stage 3 [Member]",
        "documentation": "This member stands for the transfers of financial assets to stage 3 credit impaired."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TransportAndStorageMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TransportAndStorageMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Transport and storage",
        "label": "Transport And storage [Member]",
        "documentation": "Transport And storage"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_TrdArrAdoptionDate": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "TrdArrAdoptionDate",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Trading Arrangement Adoption Date",
        "terseLabel": "Adoption Date"
       }
      }
     },
     "auth_ref": [
      "r814"
     ]
    },
    "ecd_TrdArrDuration": {
     "xbrltype": "durationItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "TrdArrDuration",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Trading Arrangement Duration",
        "terseLabel": "Arrangement Duration"
       }
      }
     },
     "auth_ref": [
      "r815"
     ]
    },
    "ecd_TrdArrExpirationDate": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "TrdArrExpirationDate",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Trading Arrangement Expiration Date",
        "terseLabel": "Expiration Date"
       }
      }
     },
     "auth_ref": [
      "r815"
     ]
    },
    "ecd_TrdArrIndName": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "TrdArrIndName",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Trading Arrangement, Individual Name",
        "terseLabel": "Name"
       }
      }
     },
     "auth_ref": [
      "r813"
     ]
    },
    "ecd_TrdArrIndTitle": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "TrdArrIndTitle",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Trading Arrangement, Individual Title",
        "terseLabel": "Title"
       }
      }
     },
     "auth_ref": [
      "r813"
     ]
    },
    "ecd_TrdArrSecuritiesAggAvailAmt": {
     "xbrltype": "sharesItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "TrdArrSecuritiesAggAvailAmt",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Trading Arrangement, Securities Aggregate Available Amount",
        "terseLabel": "Aggregate Available"
       }
      }
     },
     "auth_ref": [
      "r816"
     ]
    },
    "ecd_TrdArrTerminationDate": {
     "xbrltype": "stringItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "TrdArrTerminationDate",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Trading Arrangement Termination Date",
        "terseLabel": "Termination Date"
       }
      }
     },
     "auth_ref": [
      "r814"
     ]
    },
    "ifrs-full_TwelvemonthExpectedCreditLossesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TwelvemonthExpectedCreditLossesMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Stage 1",
        "label": "12-month expected credit losses [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the portion of lifetime expected credit losses that represent the expected credit losses that result from default events on a financial instrument that are possible within the 12 months after the reporting date. [Refer: Type of measurement of expected credit losses [domain]; Lifetime expected credit losses [member]]"
       }
      }
     },
     "auth_ref": [
      "r282",
      "r293",
      "r508",
      "r514"
     ]
    },
    "bbplc_TwentyFiveBasisPointsSensitivityAnalysisCashFlowHedgeReserveMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TwentyFiveBasisPointsSensitivityAnalysisCashFlowHedgeReserveMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Cash flow hedge reserve",
        "label": "Twenty-Five Basis Points, Sensitivity Analysis, Cash Flow Hedge Reserve [Member]",
        "documentation": "Twenty-Five Basis Points, Sensitivity Analysis, Cash Flow Hedge Reserve"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TwentyFiveBasisPointsSensitivityAnalysisFairValueThroughOtherComprehensiveIncomeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TwentyFiveBasisPointsSensitivityAnalysisFairValueThroughOtherComprehensiveIncomeMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Fair value through other comprehensive income reserve",
        "label": "Twenty-Five Basis Points, Sensitivity Analysis, Fair Value Through Other Comprehensive Income [Member]",
        "documentation": "Twenty-Five Basis Points, Sensitivity Analysis, Fair Value Through Other Comprehensive Income"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TwentyFiveBasisPointsSensitivityAnalysisMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TwentyFiveBasisPointsSensitivityAnalysisMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "+/- 25bps",
        "label": "Twenty-Five Basis Points, Sensitivity Analysis [Member]",
        "documentation": "This member stands for the twenty-five basis point movement in rates."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TwentyFiveBasisPointsSensitivityAnalysisNetInterestIncomeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TwentyFiveBasisPointsSensitivityAnalysisNetInterestIncomeMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Net interest income",
        "label": "Twenty-Five Basis Points, Sensitivity Analysis, Net Interest Income [Member]",
        "documentation": "Twenty-Five Basis Points, Sensitivity Analysis, Net Interest Income"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TwentyFiveBasisPointsSensitivityAnalysisProfitLossMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TwentyFiveBasisPointsSensitivityAnalysisProfitLossMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Effect on profit for the year (per above)",
        "label": "Twenty-Five Basis Points, Sensitivity Analysis, Profit (Loss) [Member]",
        "documentation": "Twenty-Five Basis Points, Sensitivity Analysis, Profit (Loss)"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TwentyFiveBasisPointsSensitivityAnalysisTaxationEffectsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TwentyFiveBasisPointsSensitivityAnalysisTaxationEffectsMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Taxation effects on the above",
        "label": "Twenty-Five Basis Points, Sensitivity Analysis, Taxation Effects [Member]",
        "documentation": "Twenty-Five Basis Points, Sensitivity Analysis, Taxation Effects"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TypeOfMeasurementOfExpectedCreditLossesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypeOfMeasurementOfExpectedCreditLossesAxis",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Type of measurement of expected credit losses [axis]",
        "label": "Type of measurement of expected credit losses [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r285",
      "r296",
      "r511",
      "r517"
     ]
    },
    "ifrs-full_TypeOfMeasurementOfExpectedCreditLossesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypeOfMeasurementOfExpectedCreditLossesDomain",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofcreditriskprofilebyinternalPDbandforloansandadvancesatamortisedcostcontingentliabilitiesandloancommitmentsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofcreditexposuresbyinternalPDgradeofassetsheldforsaleDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofloansandadvancesatamortisedcostbyproductDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementadjustmentstomodelsforimpairmentandEconomicuncertaintymanagementadjustmentsbystageDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposureforloancommitmentandfinancialguaranteesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Type of measurement of expected credit losses [domain]",
        "label": "Type of measurement of expected credit losses [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all types of measurement of expected credit losses. Expected credit losses are the weighted average of credit losses with the respective risks of a default occurring as the weights. This member also represents the standard value for the 'Type of measurement of expected credit losses' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r285",
      "r296",
      "r511",
      "r517"
     ]
    },
    "bbplc_TypeOfUKRFObligationAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TypeOfUKRFObligationAxis",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Type Of UKRF Obligation [Axis]",
        "label": "Type Of UKRF Obligation [Axis]",
        "documentation": "Type Of UKRF Obligation"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_TypeOfUKRFObligationDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "TypeOfUKRFObligationDomain",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsBreakdownoftheUKRFbenefitobligationDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Type Of UKRF Obligation [Domain]",
        "label": "Type Of UKRF Obligation [Domain]",
        "documentation": "Type Of UKRF Obligation [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_TypesOfFinancialAssetsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypesOfFinancialAssetsAxis",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Types of financial assets [axis]",
        "label": "Types of financial assets [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r324",
      "r325"
     ]
    },
    "ifrs-full_TypesOfFinancialAssetsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypesOfFinancialAssetsDomain",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Types of financial assets [domain]",
        "label": "Types of financial assets [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for aggregated types of financial assets. It also represents the standard value for the 'Types of financial assets' axis if no other member is used. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r324",
      "r325"
     ]
    },
    "ifrs-full_TypesOfFinancialLiabilitiesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypesOfFinancialLiabilitiesAxis",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Types of financial liabilities [axis]",
        "label": "Types of financial liabilities [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r324",
      "r325"
     ]
    },
    "ifrs-full_TypesOfFinancialLiabilitiesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypesOfFinancialLiabilitiesDomain",
     "presentation": [
      "http://www.home.barclays/role/OffsettingfinancialassetsandfinancialliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Types of financial liabilities [domain]",
        "label": "Types of financial liabilities [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for aggregated types of financial liabilities. It also represents the standard value for the 'Types of financial liabilities' axis if no other member is used. [Refer: Financial assets]"
       }
      }
     },
     "auth_ref": [
      "r324",
      "r325"
     ]
    },
    "ifrs-full_TypesOfHedgesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypesOfHedgesAxis",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Types of hedges [axis]",
        "label": "Types of hedges [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r259",
      "r267",
      "r271",
      "r494",
      "r499",
      "r503"
     ]
    },
    "ifrs-full_TypesOfHedgesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypesOfHedgesDomain",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Types of hedges [domain]",
        "label": "Types of hedges [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all types of hedges. It also represents the standard value for the 'Types of hedges' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r259",
      "r267",
      "r271",
      "r494",
      "r499",
      "r503"
     ]
    },
    "ifrs-full_TypesOfInterestRatesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypesOfInterestRatesAxis",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Types of interest rates [axis]",
        "label": "Types of interest rates [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r873"
     ]
    },
    "ifrs-full_TypesOfInterestRatesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypesOfInterestRatesDomain",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/OrdinarysharespreferencesharesandotherequityDisclosureofAT1equityinstrumentsDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Types of interest rates [domain]",
        "label": "Types of interest rates [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all types of interest rates. It also represents the standard value for the 'Types of interest rates' axis if no other member is used. [Refer: Interest rate risk [member]]"
       }
      }
     },
     "auth_ref": [
      "r873"
     ]
    },
    "ifrs-full_TypesOfRisksAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypesOfRisksAxis",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Types of risks [axis]",
        "label": "Types of risks [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r43",
      "r203",
      "r204",
      "r205",
      "r208",
      "r251",
      "r277",
      "r279",
      "r418"
     ]
    },
    "ifrs-full_TypesOfRisksDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypesOfRisksDomain",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofderivativesheldfortradingandriskmanagementDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofeffectontheincomestatementandOCIasaresultofhedgeaccountingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofexpectednotionalvaluesofcurrenthedginginstrumentsinfutureyearsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsinfairvaluehedgesDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetcashflowandnetinvestmenthedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedginginstrumentswhicharecarriedontheGroupsbalancesheetfairvaluehedgingDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofLevel3assetsandliabilitiesheldatfairvaluedisaggregatedbyproducttypeDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsensitivityanalysisofvaluationsusingunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FinancialassetsatfairvaluethroughtheincomestatementDisclosureofcreditriskofloansandadvancesdesignatedatfairvalueandrelatedcreditderivativesDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofanalysisofequitysensitivityDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmaximumexposureandeffectsofcollateralandothercreditenhancementsDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails",
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Types of risks [domain]",
        "label": "Types of risks [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all types of risks. It also represents the standard value for the 'Types of risks' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r43",
      "r203",
      "r204",
      "r205",
      "r208",
      "r251",
      "r277",
      "r279",
      "r418"
     ]
    },
    "ifrs-full_TypesOfSharebasedPaymentArrangementsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypesOfSharebasedPaymentArrangementsAxis",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofsharebasedpaymentschemesDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails",
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Types of share-based payment arrangements [axis]",
        "label": "Types of share-based payment arrangements [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r223",
      "r469"
     ]
    },
    "ifrs-full_TypesOfSharebasedPaymentArrangementsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "TypesOfSharebasedPaymentArrangementsDomain",
     "presentation": [
      "http://www.home.barclays/role/RelatedpartytransactionsandDirectorsremunerationDisclosurerequiredbytheCompaniesAct2006Details",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofsharebasedpaymentschemesDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails",
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails",
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Types of share-based payment arrangements [domain]",
        "label": "Types of share-based payment arrangements [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for an agreement between the entity or another group entity or any shareholder of the group entity and another party (including an employee) that entitles the other party to receive (a) cash or other assets of the entity for amounts that are based on the price (or value) of equity instruments (including shares or share options) of the entity or another group entity; or (b) equity instruments (including shares or share options) of the entity or another group entity, provided that the specified vesting conditions, if any, are met. It also represents the standard value for the 'Types of share-based payment arrangements' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r223",
      "r469"
     ]
    },
    "bbplc_UKRegulatoryLevies": {
     "xbrltype": "monetaryItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "UKRegulatoryLevies",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails": {
       "parentTag": "ifrs-full_OperatingExpense",
       "weight": 1.0,
       "order": 2.0
      },
      "http://www.home.barclays/role/Consolidatedincomestatement": {
       "parentTag": "ifrs-full_OperatingExpense",
       "weight": 1.0,
       "order": 4.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/Consolidatedincomestatement",
      "http://www.home.barclays/role/ParentcompanyaccountsIncomestatement",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedTerseLabel": "UK regulatory levies",
        "label": "UK Regulatory Levies",
        "documentation": "UK Regulatory Levies"
       }
      }
     },
     "auth_ref": []
    },
    "country_US": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/country/2025",
     "localname": "US",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmovementingrossexposuresandimpairmentallowanceincludingreconciliationofECLDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofincomebygeographicregionDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "United States",
        "verboseLabel": "United States",
        "label": "UNITED STATES"
       }
      }
     },
     "auth_ref": []
    },
    "currency_USD": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/currency/2025",
     "localname": "USD",
     "presentation": [
      "http://www.home.barclays/role/DerivativefinancialinstrumentsDisclosureofhedgeditemsincashflowhedgesandhedgesofnetinvestmentsinforeignoperationsDetails",
      "http://www.home.barclays/role/DerivativefinancialinstrumentsNarrativeDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureoffunctionalcurrencyoftheoperationDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofnetinterestincomesensitivityAEaRbycurrencyDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "netLabel": "USD",
        "terseLabel": "United States of America, Dollars",
        "verboseLabel": "USD foreign operations",
        "label": "United States of America, Dollars"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_USDFloatingRateNotesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "USDFloatingRateNotesMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "USD Floating Rate Notes",
        "label": "USD Floating Rate Notes [Member]",
        "documentation": "USD Floating Rate Notes"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_USDLIBORActionsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "USDLIBORActionsMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "USD LIBOR Actions",
        "label": "USD LIBOR Actions [Member]",
        "documentation": "USD LIBOR Actions"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_USIntermediateHoldingCompanyTaxGroupMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "USIntermediateHoldingCompanyTaxGroupMember",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "US Intermediate Holding Company Tax Group (\"IHC Tax Group\")",
        "label": "US Intermediate Holding Company Tax Group [Member]",
        "documentation": "This member stands for the Intermediate Holding company."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_USResidentialAndCommercialMortgageRelatedActivityAndLitigationMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "USResidentialAndCommercialMortgageRelatedActivityAndLitigationMember",
     "presentation": [
      "http://www.home.barclays/role/LegalcompetitionandregulatorymattersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "US residential and commercial mortgage-related activity and litigation",
        "label": "US Residential And Commercial Mortgage-Related Activity And Litigation [Member]",
        "documentation": "Various investigations and civil litigation relating to secondary market trading of US residential mortgage-backed securities (RMBS) and US commercial mortgage-backed securities (CMBS)."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_UnallocatedAmountsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "UnallocatedAmountsMember",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails",
      "http://www.home.barclays/role/SegmentalreportingDisclosureofanalysisofresultsbybusinessDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Head Office",
        "label": "Unallocated amounts [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for items that have not been allocated to operating segments."
       }
      }
     },
     "auth_ref": [
      "r695",
      "r696"
     ]
    },
    "bbplc_UncollateralisedDerivativeFundingMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "UncollateralisedDerivativeFundingMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureoffairvalueadjustmentsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Uncollateralised derivative funding",
        "label": "Uncollateralised Derivative Funding [Member]",
        "documentation": "This member stands for uncollateralised derivative funding. This funding fair value adjustment accounts for the impact of incorporating the cost of funding into the valuation of uncollateralised and partially collateralised derivative portfolios and collateralised derivatives where the terms of the agreement do not allow the rehypothecation of collateral received."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_UnconsolidatedStructuredEntitiesAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "UnconsolidatedStructuredEntitiesAxis",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails",
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Unconsolidated structured entities [axis]",
        "label": "Unconsolidated structured entities [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r160",
      "r525"
     ]
    },
    "ifrs-full_UnconsolidatedStructuredEntitiesDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "UnconsolidatedStructuredEntitiesDomain",
     "presentation": [
      "http://www.home.barclays/role/AssetspledgedcollateralreceivedandassetstransferredDisclosureofrecoursetotransferredassetsDetails",
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/SecuritisationsDisclosureoftransfersoffinancialassetsthatdonotresultinderecognitionDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails",
      "http://www.home.barclays/role/StructuredentitiesNatureofinterestDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Unconsolidated structured entities [domain]",
        "label": "Unconsolidated structured entities [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for the standard value for the 'Unconsolidated structured entities' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r160",
      "r525"
     ]
    },
    "ifrs-full_UnconsolidatedStructuredEntitiesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "UnconsolidatedStructuredEntitiesMember",
     "presentation": [
      "http://www.home.barclays/role/PrincipalsubsidiariesNarrativeDetails",
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails",
      "http://www.home.barclays/role/StructuredentitiesSummaryofinterestsinunconsolidatedstructuredentitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Unconsolidated structured entities",
        "terseLabel": "Total",
        "label": "Total for all unconsolidated structured entities [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for unconsolidated structured entities. A structured entity is an entity that has been designed so that voting or similar rights are not the dominant factor in deciding who controls the entity, such as when any voting rights relate to administrative tasks only and the relevant activities are directed by means of contractual arrangements. [Refer: Consolidated [member]]"
       }
      }
     },
     "auth_ref": [
      "r160",
      "r525"
     ]
    },
    "ifrs-full_UndatedSubordinatedLiabilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "UndatedSubordinatedLiabilities",
     "crdr": "credit",
     "calculation": {
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedanddatedsubordinatedliabilitiesDetails": {
       "parentTag": "bbplc_SubordinatedLiabilitiesIncludingThoseDesignatedAtFairValue",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedanddatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofundatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Undated subordinated liabilities",
        "label": "Undated subordinated liabilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of subordinated liabilities that do not have a specified repayment date. [Refer: Subordinated liabilities]"
       }
      }
     },
     "auth_ref": [
      "r880"
     ]
    },
    "bbplc_UnderwritingSyndicationAndCommitmentFeesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "UnderwritingSyndicationAndCommitmentFeesMember",
     "presentation": [
      "http://www.home.barclays/role/NetfeeandcommissionincomeSummaryoftotalfeesinscopeofIFRS15RevenuesfromContractswithCustomersDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Underwriting and syndication",
        "label": "Underwriting, Syndication And Commitment Fees [Member]",
        "documentation": "This member stands for fees which are earned for the distribution of client equity or debt securities, which includes a commitment to purchase such securities if they are not sold to third parties. Syndication and commitment fees include the arrangement and administration of a loan syndication, which includes a commitment to provide the loan if it is not sold to third parties."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_UndrawnBorrowingFacilities": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "UndrawnBorrowingFacilities",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/StructuredentitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Undrawn borrowing facilities",
        "label": "Undrawn borrowing facilities"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of undrawn borrowing facilities that may be available for future operating activities and to settle capital commitments. [Refer: Capital commitments]"
       }
      }
     },
     "auth_ref": [
      "r632"
     ]
    },
    "bbplc_UndrawnContractuallyCommittedFacilitiesAndGuaranteesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "UndrawnContractuallyCommittedFacilitiesAndGuaranteesMember",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Undrawn contractually committed facilities and guarantees",
        "label": "Undrawn Contractually Committed Facilities And Guarantees [Member]",
        "documentation": "This member stands for provisions are made if it is probable that a facility will be drawn and the resulting asset is expected to have a realisable value that is less than the amount advanced."
       }
      }
     },
     "auth_ref": []
    },
    "ecd_UndrlygSecurityMktPriceChngPct": {
     "xbrltype": "pureItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "UndrlygSecurityMktPriceChngPct",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Underlying Security Market Price Change, Percent",
        "terseLabel": "Underlying Security Market Price Change"
       }
      }
     },
     "auth_ref": [
      "r810"
     ]
    },
    "bbplc_UnemploymentEconomicCoreVariableMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "UnemploymentEconomicCoreVariableMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Unemployment",
        "label": "Unemployment, Economic Core Variable [Member]",
        "documentation": "This member stands for unemployment, a key historic macroeconomic core variable. The unemployment is compared against the forecast paths of the probability weights for each scenario, demonstrating the lowest point in the Upside scenarios; 5 year average in Baseline; highest point in Downside scenarios."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_UnitedStatesBranchTaxGroupMemberMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "UnitedStatesBranchTaxGroupMemberMember",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofdeferredtaxassetsandliabilitiesDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Barclays Bank PLC's US Branch Tax Group",
        "label": "United States Branch Tax Group Member [Member]",
        "documentation": "United States Branch Tax Group Member"
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_UnobservableInputsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "UnobservableInputsAxis",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Unobservable inputs [axis]",
        "label": "Unobservable inputs [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r165",
      "r870"
     ]
    },
    "ifrs-full_UnobservableInputsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "UnobservableInputsDomain",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofsensitivityofthevalueinusetokeyjudgementsinthecalculationsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Unobservable inputs [domain]",
        "label": "Unobservable inputs [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for all the unobservable inputs. It also represents the standard value for the 'Unobservable inputs' axis if no other member is used."
       }
      }
     },
     "auth_ref": [
      "r165",
      "r870"
     ]
    },
    "ifrs-full_UnusedProvisionReversedOtherProvisions": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "UnusedProvisionReversedOtherProvisions",
     "crdr": "debit",
     "presentation": [
      "http://www.home.barclays/role/ProvisionsDisclosureofmovementsinprovisionsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "negatedLabel": "Unused amounts reversed",
        "label": "Unused provision reversed, other provisions"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount reversed for unused other provisions. [Refer: Other provisions]"
       }
      }
     },
     "auth_ref": [
      "r94",
      "r444"
     ]
    },
    "ifrs-full_UnusedTaxCreditsForWhichNoDeferredTaxAssetRecognised": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "UnusedTaxCreditsForWhichNoDeferredTaxAssetRecognised",
     "presentation": [
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Unused tax credits for which no deferred tax asset recognised",
        "label": "Unused tax credits for which no deferred tax asset recognised"
       }
      },
      "en": {
       "role": {
        "documentation": "The amount of unused tax credits for which no deferred tax asset is recognised in the statement of financial position. [Refer: Unused tax credits [member]]"
       }
      }
     },
     "auth_ref": [
      "r6",
      "r394"
     ]
    },
    "ifrs-full_UnusedTaxLossesMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "UnusedTaxLossesMember",
     "presentation": [
      "http://www.home.barclays/role/TaxDisclosureofmovementsondeferredtaxassetsandliabilitiesduringtheyearbeforeoffsettingDetails",
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Unused tax losses",
        "terseLabel": "Tax losses carried forward",
        "label": "Unused tax losses [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for tax losses that have been incurred and are carried forward for use against future taxable profit."
       }
      }
     },
     "auth_ref": [
      "r10",
      "r397"
     ]
    },
    "bbplc_UpsideOneMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "UpsideOneMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Upside 1",
        "label": "Upside 1 [member]",
        "documentation": "The upside 1 scenario. The favourable scenarios are calibrated to be symmetric to the adverse scenarios, subject to a ceiling calibrated to relevant recent favourable benchmark scenarios."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_UpsideScenarioMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "UpsideScenarioMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementMeasurementuncertaintyandsensitivityanalysisDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Upside scenario",
        "label": "Upside Scenario [Member]",
        "documentation": "Upside Scenario"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_UpsideTwoMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "UpsideTwoMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofECLunder100weightedscenariosforkeymodelledportfoliosDetails",
      "http://www.home.barclays/role/RiskManagementDisclosureofmacroeconomicvariablesusedinthecalculationofECLandScenarioprobabilityweightingDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Upside 2",
        "label": "Upside 2 [member]",
        "documentation": "The upside 2 scenario. The favourable scenarios are calibrated to be symmetric to the adverse scenarios, subject to a ceiling calibrated to relevant recent favourable benchmark scenarios."
       }
      }
     },
     "auth_ref": []
    },
    "ifrs-full_UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill": {
     "xbrltype": "durationItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill",
     "presentation": [
      "http://www.home.barclays/role/GoodwillandintangibleassetsDisclosureofamortisationperiodsforgoodwillandintangibleassetsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Amortisation period",
        "label": "Useful life measured as period of time, intangible assets other than goodwill"
       }
      },
      "en": {
       "role": {
        "documentation": "The useful life, measured as period of time, used for intangible assets other than goodwill. [Refer: Intangible assets other than goodwill]"
       }
      }
     },
     "auth_ref": [
      "r100",
      "r449"
     ]
    },
    "ifrs-full_ValuationTechniquesUsedInFairValueMeasurementAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ValuationTechniquesUsedInFairValueMeasurementAxis",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureoffairvalueadjustmentsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Valuation techniques used in fair value measurement [axis]",
        "label": "Valuation techniques used in fair value measurement [axis]"
       }
      },
      "en": {
       "role": {
        "documentation": "The axis of a table defines the relationship between the members in the table and the line items or concepts that complete the table."
       }
      }
     },
     "auth_ref": [
      "r165"
     ]
    },
    "ifrs-full_ValuationTechniquesUsedInFairValueMeasurementDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ValuationTechniquesUsedInFairValueMeasurementDomain",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureoffairvalueadjustmentsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails",
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Valuation techniques used in fair value measurement [domain]",
        "label": "Valuation techniques used in fair value measurement [domain]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for valuation techniques used by the entity to measure fair value. It also represents the standard value for the 'Valuation techniques used in fair value measurement' axis if no other member is used. [Refer: At fair value [member]]"
       }
      }
     },
     "auth_ref": [
      "r165"
     ]
    },
    "ifrs-full_ValueAtRisk": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "ValueAtRisk",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Value at risk",
        "label": "Value at risk"
       }
      },
      "en": {
       "role": {
        "documentation": "The measure of a potential loss exposure as a result of future market movements, based on a specified confidence interval and measurement horizon."
       }
      }
     },
     "auth_ref": [
      "r874"
     ]
    },
    "bbplc_VariousSubordinatedLoansMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "VariousSubordinatedLoansMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails",
      "http://www.home.barclays/role/SubordinatedliabilitiesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Various subordinated loans",
        "label": "Various Subordinated Loans [Member]",
        "documentation": "This member stands for various subordinated intra-group loans."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_VariousZeroCouponLoansMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "VariousZeroCouponLoansMember",
     "presentation": [
      "http://www.home.barclays/role/SubordinatedliabilitiesDisclosureofdatedsubordinatedliabilitiesDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Various Zero Coupon Callable Loans",
        "label": "Various Zero Coupon Loans [Member]",
        "documentation": "This member stands for the Zero coupon loans held by the entity due 2050."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_VestingPeriodFourMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "VestingPeriodFourMember",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Vesting period four",
        "label": "Vesting Period Four [Member]",
        "documentation": "Vesting Period Four"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_VestingPeriodOneMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "VestingPeriodOneMember",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Vesting period one",
        "label": "Vesting Period One [Member]",
        "documentation": "Vesting Period One"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_VestingPeriodThreeMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "VestingPeriodThreeMember",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Vesting period three",
        "label": "Vesting Period Three [Member]",
        "documentation": "Vesting Period Three"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_VestingPeriodTwoMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "VestingPeriodTwoMember",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Vesting period two",
        "label": "Vesting Period Two [Member]",
        "documentation": "Vesting Period Two"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_VestingPeriodsAxis": {
     "xbrltype": "stringItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "VestingPeriodsAxis",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Vesting, Periods [Axis]",
        "label": "Vesting, Periods [Axis]",
        "documentation": "Vesting, Periods"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_VestingPeriodsDomain": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "VestingPeriodsDomain",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Vesting, Periods [Domain]",
        "label": "Vesting, Periods [Domain]",
        "documentation": "Vesting, Periods [Domain]"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_VstngDtFrValOfEqtyAwrdsGrntdAndVstdInCvrdYrMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "VstngDtFrValOfEqtyAwrdsGrntdAndVstdInCvrdYrMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member]",
        "terseLabel": "Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year"
       }
      }
     },
     "auth_ref": [
      "r779"
     ]
    },
    "ifrs-full_WagesAndSalaries": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "WagesAndSalaries",
     "crdr": "debit",
     "calculation": {
      "http://www.home.barclays/role/StaffcostsDetails": {
       "parentTag": "bbplc_StaffCompensationCosts",
       "weight": 1.0,
       "order": 2.0
      }
     },
     "presentation": [
      "http://www.home.barclays/role/StaffcostsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Salaries",
        "label": "Wages and salaries"
       }
      }
     },
     "auth_ref": [
      "r851"
     ]
    },
    "ifrs-full_WeightedAverageDurationOfDefinedBenefitObligation2019": {
     "xbrltype": "durationItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "WeightedAverageDurationOfDefinedBenefitObligation2019",
     "presentation": [
      "http://www.home.barclays/role/RetirementbenefitsNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Weighted average duration of the benefit payments reflected in defined benefit obligation, UKRF",
        "label": "Weighted average duration of defined benefit obligation"
       }
      },
      "en": {
       "role": {
        "documentation": "The weighted average duration of a defined benefit obligation. [Refer: Weighted average [member]]"
       }
      }
     },
     "auth_ref": [
      "r37"
     ]
    },
    "ifrs-full_WeightedAverageExercisePriceOfShareOptionsExercisedInSharebasedPaymentArrangement2019": {
     "xbrltype": "perShareItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "WeightedAverageExercisePriceOfShareOptionsExercisedInSharebasedPaymentArrangement2019",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Exercised/released in the year, weighted average exercise price (in GBP per share)",
        "label": "Weighted average exercise price of share options exercised in share-based payment arrangement"
       }
      },
      "en": {
       "role": {
        "documentation": "The weighted average exercise price of share options exercised in a share-based payment arrangement. [Refer: Weighted average [member]]"
       }
      }
     },
     "auth_ref": [
      "r216",
      "r464"
     ]
    },
    "ifrs-full_WeightedAverageExercisePriceOfShareOptionsExpiredInSharebasedPaymentArrangement2019": {
     "xbrltype": "perShareItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "WeightedAverageExercisePriceOfShareOptionsExpiredInSharebasedPaymentArrangement2019",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Less: expired in the year, weighted average exercise price (in GBP per share)",
        "label": "Weighted average exercise price of share options expired in share-based payment arrangement"
       }
      },
      "en": {
       "role": {
        "documentation": "The weighted average exercise price of share options expired in a share-based payment arrangement. [Refer: Weighted average [member]]"
       }
      }
     },
     "auth_ref": [
      "r217",
      "r465"
     ]
    },
    "ifrs-full_WeightedAverageExercisePriceOfShareOptionsForfeitedInSharebasedPaymentArrangement2019": {
     "xbrltype": "perShareItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "WeightedAverageExercisePriceOfShareOptionsForfeitedInSharebasedPaymentArrangement2019",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Less: forfeited in the year, weighted average exercise price (in GBP per share)",
        "label": "Weighted average exercise price of share options forfeited in share-based payment arrangement"
       }
      },
      "en": {
       "role": {
        "documentation": "The weighted average exercise price of share options forfeited in a share-based payment arrangement. [Refer: Weighted average [member]]"
       }
      }
     },
     "auth_ref": [
      "r215",
      "r463"
     ]
    },
    "ifrs-full_WeightedAverageExercisePriceOfShareOptionsGrantedInSharebasedPaymentArrangement2019": {
     "xbrltype": "perShareItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "WeightedAverageExercisePriceOfShareOptionsGrantedInSharebasedPaymentArrangement2019",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Granted in the year, weighted average exercise price (in GBP per share)",
        "label": "Weighted average exercise price of share options granted in share-based payment arrangement"
       }
      },
      "en": {
       "role": {
        "documentation": "The weighted average exercise price of share options granted in a share-based payment arrangement. [Refer: Weighted average [member]]"
       }
      }
     },
     "auth_ref": [
      "r214",
      "r462"
     ]
    },
    "ifrs-full_WeightedAverageExercisePriceOfShareOptionsOutstandingInSharebasedPaymentArrangement2019": {
     "xbrltype": "perShareItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "WeightedAverageExercisePriceOfShareOptionsOutstandingInSharebasedPaymentArrangement2019",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails",
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Weighted average share price at exercise/release during year (in GBP per share)",
        "periodStartLabel": "Outstanding at beginning of year, weighted average exercise price (in GBP per share)",
        "periodEndLabel": "Outstanding at end of year, weighted average exercise price (in GBP per share)",
        "label": "Weighted average exercise price of share options outstanding in share-based payment arrangement"
       }
      },
      "en": {
       "role": {
        "documentation": "The weighted average exercise price of share options outstanding in a share-based payment arrangement. [Refer: Weighted average [member]]"
       }
      }
     },
     "auth_ref": [
      "r213",
      "r218",
      "r461",
      "r466"
     ]
    },
    "ifrs-full_WeightedAverageFairValueAtMeasurementDateShareOptionsGranted": {
     "xbrltype": "monetaryItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "WeightedAverageFairValueAtMeasurementDateShareOptionsGranted",
     "crdr": "credit",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Weighted average fair value per award granted in year",
        "label": "Weighted average fair value at measurement date, share options granted"
       }
      },
      "en": {
       "role": {
        "documentation": "The weighted average fair value of share options granted during the period at the measurement date. [Refer: Weighted average [member]]"
       }
      }
     },
     "auth_ref": [
      "r225"
     ]
    },
    "ifrs-full_WeightedAverageMember": {
     "xbrltype": "domainItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "WeightedAverageMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofmanagementValueatRiskDetails",
      "http://www.home.barclays/role/TaxDisclosureofreconciliationbetweentheactualtaxchargeandthecorporatetaxrateDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "verboseLabel": "Average",
        "terseLabel": "Weighted average",
        "label": "Weighted average [member]"
       }
      },
      "en": {
       "role": {
        "documentation": "This member stands for an average in which each quantity to be averaged is assigned a weight that determines the relative effect of each quantity on the average."
       }
      }
     },
     "auth_ref": [
      "r177",
      "r202",
      "r649",
      "r651",
      "r875"
     ]
    },
    "ifrs-full_WeightedAverageRemainingContractualLifeOfOutstandingShareOptions2019": {
     "xbrltype": "durationItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "WeightedAverageRemainingContractualLifeOfOutstandingShareOptions2019",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofshareoptionandawardplansDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Weighted average remaining contractual life",
        "label": "Weighted average remaining contractual life of outstanding share options"
       }
      },
      "en": {
       "role": {
        "documentation": "The weighted average remaining contractual life of outstanding share options. [Refer: Weighted average [member]]"
       }
      }
     },
     "auth_ref": [
      "r222"
     ]
    },
    "ifrs-full_WeightedAverageSharePrice2019": {
     "xbrltype": "perShareItemType",
     "nsuri": "https://xbrl.ifrs.org/taxonomy/2025-03-27/ifrs-full",
     "localname": "WeightedAverageSharePrice2019",
     "presentation": [
      "http://www.home.barclays/role/SharebasedpaymentsDisclosureofmovementsinoptionsandawardsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Exercisable, weighted average exercise price (in GBP per share)",
        "label": "Weighted average share price"
       }
      },
      "en": {
       "role": {
        "documentation": "The weighted average share price. [Refer: Weighted average [member]]"
       }
      }
     },
     "auth_ref": [
      "r221"
     ]
    },
    "bbplc_WeightedExpectedCreditLossUpliftPercentage": {
     "xbrltype": "percentItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "WeightedExpectedCreditLossUpliftPercentage",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementECLunder100weightedscenariosformodelledportfoliosDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Weighted expected credit loss, uplift percentage",
        "label": "Weighted Expected Credit Loss, Uplift Percentage",
        "documentation": "The amount (expressed as a percentage) of weighted expected credit lossuplift from the baseline expected credit loss."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_WholesaleAndRetailDistributionAndLeisureMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "WholesaleAndRetailDistributionAndLeisureMember",
     "presentation": [
      "http://www.home.barclays/role/RiskManagementDisclosureofconcentrationsofcreditriskbyindustryandgeographyDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Wholesale and retail distribution and leisure",
        "label": "Wholesale And Retail Distribution And Leisure [Member]",
        "documentation": "This member stands for the wholesale and retail distribution and leisure industry."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_WholesalePortfoliosMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "WholesalePortfoliosMember",
     "presentation": [
      "http://www.home.barclays/role/CreditimpairmentchargesreleasesNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Wholesale portfolios",
        "label": "Wholesale Portfolios [member]",
        "documentation": "This member stands for the wholesale portfolios of the entity."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_WithinElevenToTwentyYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "WithinElevenToTwentyYearsMember",
     "presentation": [
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Within eleven to twenty years",
        "label": "Within Eleven To Twenty Years [Member]",
        "documentation": "This member stands for expiration of carryforward within 11 to 20 years."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_WithinFiveYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "WithinFiveYearsMember",
     "presentation": [
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Within five years",
        "label": "Within Five Years [Member]",
        "documentation": "This member stands for expiration of carryforward within 5 years."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_WithinSixToTenYearsMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "WithinSixToTenYearsMember",
     "presentation": [
      "http://www.home.barclays/role/TaxNarrativeDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Within six to ten years",
        "label": "Within Six To Ten Years [Member]",
        "documentation": "This member stands for expiration of carryforward within 6 to 10 years."
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_WooriBCPegasusSecuritizationSpecialtyCo.LtdMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "WooriBCPegasusSecuritizationSpecialtyCo.LtdMember",
     "presentation": [
      "http://www.home.barclays/role/RelatedUndertakingsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Woori BC Pegasus Securitization Specialty Co. Ltd",
        "label": "Woori BC Pegasus Securitization Specialty Co. Ltd [Member]",
        "documentation": "Woori BC Pegasus Securitization Specialty Co. Ltd"
       }
      }
     },
     "auth_ref": []
    },
    "bbplc_YieldMeasurementInputMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://www.home.barclays/20251231",
     "localname": "YieldMeasurementInputMember",
     "presentation": [
      "http://www.home.barclays/role/FairvalueoffinancialinstrumentsDisclosureofsignificantunobservableinputsDetails"
     ],
     "lang": {
      "en-us": {
       "role": {
        "terseLabel": "Yield",
        "label": "Yield, Measurement Input [Member]",
        "documentation": "Yield, Measurement Input"
       }
      }
     },
     "auth_ref": []
    },
    "ecd_YrEndFrValOfEqtyAwrdsGrntdInCvrdYrOutsdngAndUnvstdMember": {
     "xbrltype": "domainItemType",
     "nsuri": "http://xbrl.sec.gov/ecd/2025",
     "localname": "YrEndFrValOfEqtyAwrdsGrntdInCvrdYrOutsdngAndUnvstdMember",
     "presentation": [
      "http://xbrl.sec.gov/ecd/role/PvpDisclosure"
     ],
     "lang": {
      "en-us": {
       "role": {
        "label": "Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member]",
        "terseLabel": "Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested"
       }
      }
     },
     "auth_ref": [
      "r777"
     ]
    }
   }
  }
 },
 "std_ref": {
  "r0": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "10",
   "IssueDate": "2025-01-01",
   "Paragraph": "13",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=10&code=ifrs-tx-2025-en-r&anchor=para_13&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r1": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "79",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_79&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r2": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "81",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_81_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r3": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "81",
   "Subparagraph": "ab",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_81_ab&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r4": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "81",
   "Subparagraph": "c",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_81_c_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r5": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "81",
   "Subparagraph": "c",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_81_c_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r6": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "81",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_81_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r7": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "81",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_81_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r8": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "81",
   "Subparagraph": "g",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_81_g_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r9": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "81",
   "Subparagraph": "g",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_81_g_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r10": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "81",
   "Subparagraph": "g",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_81_g&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r11": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "88B",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_88B&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r12": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Section": "Disclosure",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IAS12_g79-88_TI",
   "URIDate": "2025-03-27"
  },
  "r13": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "73",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=16&code=ifrs-tx-2025-en-r&anchor=para_73_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r14": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "73",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=16&code=ifrs-tx-2025-en-r&anchor=para_73_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r15": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "73",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=16&code=ifrs-tx-2025-en-r&anchor=para_73_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r16": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "73",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=16&code=ifrs-tx-2025-en-r&anchor=para_73&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r17": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "75",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=16&code=ifrs-tx-2025-en-r&anchor=para_75_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r18": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Section": "Disclosure",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=16&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IAS16_g73-79_TI",
   "URIDate": "2025-03-27"
  },
  "r19": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "138",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_138&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r20": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "140",
   "Subparagraph": "a",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_140_a_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r21": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "140",
   "Subparagraph": "a",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_140_a_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r22": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "140",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_140_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r23": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "141",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_141_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r24": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "141",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_141_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r25": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "141",
   "Subparagraph": "c",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_141_c_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r26": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "141",
   "Subparagraph": "c",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_141_c_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r27": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "141",
   "Subparagraph": "c",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_141_c_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r28": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "141",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_141_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r29": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "141",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_141_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r30": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "141",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_141_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r31": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "141",
   "Subparagraph": "g",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_141_g&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r32": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "141",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_141&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r33": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "142",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_142&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r34": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "145",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_145_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r35": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "145",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_145&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r36": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "147",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_147_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r37": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "147",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_147_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r38": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "148",
   "Subparagraph": "d",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_148_d_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r39": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Section": "Scope",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IAS19_g2-7_TI",
   "URIDate": "2025-03-27"
  },
  "r40": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "21",
   "IssueDate": "2025-01-01",
   "Paragraph": "48",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=21&code=ifrs-tx-2025-en-r&anchor=para_48&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r41": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "21",
   "IssueDate": "2025-01-01",
   "Paragraph": "52",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=21&code=ifrs-tx-2025-en-r&anchor=para_52_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r42": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "21",
   "IssueDate": "2025-01-01",
   "Paragraph": "A19",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=21&code=ifrs-tx-2025-en-r&anchor=para_A19_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r43": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "21",
   "IssueDate": "2025-01-01",
   "Paragraph": "A19",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=21&code=ifrs-tx-2025-en-r&anchor=para_A19_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r44": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "21",
   "IssueDate": "2025-01-01",
   "Section": "Disclosure",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=21&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IAS21_g51-57_TI",
   "URIDate": "2025-03-27"
  },
  "r45": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "17",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_17_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r46": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "17",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_17_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r47": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "17",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_17_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r48": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "17",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_17_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r49": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "17",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_17&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r50": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "18",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_18_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r51": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "18",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_18&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r52": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "18A",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_18A&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r53": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "19",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_19_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r54": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "19",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_19_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r55": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "19",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_19_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r56": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "19",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_19_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r57": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "19",
   "Subparagraph": "g",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_19_g&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r58": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "19",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_19&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r59": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "20",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_20&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r60": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Section": "Disclosures",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IAS24_g13-24_TI",
   "URIDate": "2025-03-27"
  },
  "r61": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "26",
   "IssueDate": "2025-01-01",
   "Paragraph": "35",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=26&code=ifrs-tx-2025-en-r&anchor=para_35_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r62": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "26",
   "IssueDate": "2025-01-01",
   "Paragraph": "35",
   "Subparagraph": "b",
   "Clause": "viii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=26&code=ifrs-tx-2025-en-r&anchor=para_35_b_viii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r63": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "27",
   "IssueDate": "2025-01-01",
   "Paragraph": "10",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=27&code=ifrs-tx-2025-en-r&anchor=para_10&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r64": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "27",
   "IssueDate": "2025-01-01",
   "Paragraph": "16",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=27&code=ifrs-tx-2025-en-r&anchor=para_16_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r65": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "27",
   "IssueDate": "2025-01-01",
   "Paragraph": "16",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=27&code=ifrs-tx-2025-en-r&anchor=para_16_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r66": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "27",
   "IssueDate": "2025-01-01",
   "Paragraph": "17",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=27&code=ifrs-tx-2025-en-r&anchor=para_17_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r67": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "27",
   "IssueDate": "2025-01-01",
   "Paragraph": "17",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=27&code=ifrs-tx-2025-en-r&anchor=para_17_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r68": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "33",
   "IssueDate": "2025-01-01",
   "Paragraph": "70",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=33&code=ifrs-tx-2025-en-r&anchor=para_70_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r69": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "34",
   "IssueDate": "2025-01-01",
   "Paragraph": "16A",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=34&code=ifrs-tx-2025-en-r&anchor=para_16A_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r70": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "126",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_126_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r71": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "126",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_126_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r72": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "126",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_126&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r73": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "129",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_129_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r74": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "129",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_129_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r75": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "130",
   "Subparagraph": "d",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_130_d_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r76": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "130",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_130_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r77": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "130",
   "Subparagraph": "f",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_130_f_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r78": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "130",
   "Subparagraph": "g",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_130_g&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r79": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "130",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_130&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r80": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "134",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_134_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r81": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "134",
   "Subparagraph": "d",
   "Clause": "iv",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_134_d_iv&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r82": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "134",
   "Subparagraph": "e",
   "Clause": "iiA",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_134_e_iiA&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r83": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "134",
   "Subparagraph": "e",
   "Clause": "iv",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_134_e_iv&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r84": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "134",
   "Subparagraph": "f",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_134_f_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r85": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "134",
   "Subparagraph": "f",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_134_f_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r86": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "134",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_134&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r87": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "135",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_135_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r88": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "135",
   "Subparagraph": "e",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_135_e_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r89": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "135",
   "Subparagraph": "e",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_135_e_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r90": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "135",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_135&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r91": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Section": "Disclosure",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IAS36_g126-137_TI",
   "URIDate": "2025-03-27"
  },
  "r92": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "37",
   "IssueDate": "2025-01-01",
   "Paragraph": "84",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&anchor=para_84_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r93": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "37",
   "IssueDate": "2025-01-01",
   "Paragraph": "84",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&anchor=para_84_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r94": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "37",
   "IssueDate": "2025-01-01",
   "Paragraph": "84",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&anchor=para_84_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r95": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "37",
   "IssueDate": "2025-01-01",
   "Paragraph": "84",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&anchor=para_84&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r96": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "37",
   "IssueDate": "2025-01-01",
   "Paragraph": "85",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&anchor=para_85_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r97": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "37",
   "IssueDate": "2025-01-01",
   "Paragraph": "86",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&anchor=para_86_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r98": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "37",
   "IssueDate": "2025-01-01",
   "Paragraph": "86",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&anchor=para_86&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r99": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "37",
   "IssueDate": "2025-01-01",
   "Paragraph": "88",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&anchor=para_88&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r100": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "38",
   "IssueDate": "2025-01-01",
   "Paragraph": "118",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2025-en-r&anchor=para_118_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r101": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "38",
   "IssueDate": "2025-01-01",
   "Paragraph": "118",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2025-en-r&anchor=para_118_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r102": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "38",
   "IssueDate": "2025-01-01",
   "Paragraph": "118",
   "Subparagraph": "e",
   "Clause": "vi",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2025-en-r&anchor=para_118_e_vi&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r103": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "38",
   "IssueDate": "2025-01-01",
   "Paragraph": "118",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2025-en-r&anchor=para_118_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r104": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "38",
   "IssueDate": "2025-01-01",
   "Paragraph": "118",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2025-en-r&anchor=para_118&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r105": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "38",
   "IssueDate": "2025-01-01",
   "Section": "Disclosure",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IAS38_g118-128_TI",
   "URIDate": "2025-03-27"
  },
  "r106": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "39",
   "IssueDate": "2025-01-01",
   "Paragraph": "102",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=39&code=ifrs-tx-2025-en-r&anchor=para_102_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r107": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "39",
   "IssueDate": "2025-01-01",
   "Paragraph": "102",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=39&code=ifrs-tx-2025-en-r&anchor=para_102&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r108": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "39",
   "IssueDate": "2025-01-01",
   "Paragraph": "86",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=39&code=ifrs-tx-2025-en-r&anchor=para_86_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r109": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "39",
   "IssueDate": "2025-01-01",
   "Paragraph": "86",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=39&code=ifrs-tx-2025-en-r&anchor=para_86_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r110": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "39",
   "IssueDate": "2025-01-01",
   "Paragraph": "86",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=39&code=ifrs-tx-2025-en-r&anchor=para_86_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r111": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "40",
   "IssueDate": "2025-01-01",
   "Paragraph": "32A",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=40&code=ifrs-tx-2025-en-r&anchor=para_32A&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r112": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "40",
   "IssueDate": "2025-01-01",
   "Paragraph": "76",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=40&code=ifrs-tx-2025-en-r&anchor=para_76&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r113": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "40",
   "IssueDate": "2025-01-01",
   "Paragraph": "79",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=40&code=ifrs-tx-2025-en-r&anchor=para_79_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r114": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "40",
   "IssueDate": "2025-01-01",
   "Paragraph": "79",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=40&code=ifrs-tx-2025-en-r&anchor=para_79_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r115": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "41",
   "IssueDate": "2025-01-01",
   "Paragraph": "50",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=41&code=ifrs-tx-2025-en-r&anchor=para_50&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r116": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "41",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=41&code=ifrs-tx-2025-en-r&anchor=para_54_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r117": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "10",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_10&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r118": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "21",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_21&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r119": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "25",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_25&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r120": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "28",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_28&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r121": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "31",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_31&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r122": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r123": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "39",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_39&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r124": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "40",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_40_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r125": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "44B",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_44B_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r126": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "44B",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_44B_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r127": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "44H",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_44H_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r128": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_45&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r129": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "50",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_50_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r130": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "24",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2025-en-r&anchor=para_24_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r131": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "24",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2025-en-r&anchor=para_24_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r132": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "32",
   "Subparagraph": "a",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2025-en-r&anchor=para_32_a_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r133": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "32",
   "Subparagraph": "a",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2025-en-r&anchor=para_32_a_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r134": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "1",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_1&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r135": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "12",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_12_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r136": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "12",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_12_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r137": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "19B",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_19B_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r138": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "19F",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_19F&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r139": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "2",
   "Subparagraph": "b",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_2_b_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r140": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "2",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_2_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r141": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "21",
   "Subparagraph": "a",
   "Clause": "iv",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_21_a_iv&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r142": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "21",
   "Subparagraph": "b",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_21_b_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r143": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "26",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_26&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r144": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "27",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_27_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r145": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "29",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_29_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r146": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "29",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_29_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r147": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B12",
   "Subparagraph": "b",
   "Clause": "ix",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B12_b_ix&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r148": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B12",
   "Subparagraph": "b",
   "Clause": "viii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B12_b_viii&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r149": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B13",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B13_a&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r150": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B13",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B13_d&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r151": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B13",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B13_f&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r152": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B13",
   "Subparagraph": "g",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B13_g&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r153": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B16",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B16_a&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r154": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B16",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B16_c&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r155": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B16",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B16_d&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r156": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B16",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B16&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r157": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B4",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B4_a&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r158": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B4",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B4_b&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r159": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B4",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B4_d&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r160": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B4",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B4_e&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r161": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Section": "Nature of the risks associated with an entity's interests in consolidated structured entities",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IFRS12_g14-17_TI",
   "URIDate": "2025-03-27"
  },
  "r162": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r163": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r164": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r165": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r166": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "e",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_e_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r167": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "e",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_e_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r168": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "e",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_e_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r169": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "e",
   "Clause": "iv",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_e_iv&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r170": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r171": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r172": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "h",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_h&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r173": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r174": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "97",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_97&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r175": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "98",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_98&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r176": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Section": "Disclosure",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IFRS13_g91-99_TI",
   "URIDate": "2025-03-27"
  },
  "r177": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "14",
   "IssueDate": "2025-01-01",
   "Paragraph": "33",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=14&code=ifrs-tx-2025-en-r&anchor=para_33_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r178": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "15",
   "IssueDate": "2025-01-01",
   "Paragraph": "105",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2025-en-r&anchor=para_105&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r179": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "15",
   "IssueDate": "2025-01-01",
   "Paragraph": "113",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2025-en-r&anchor=para_113_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r180": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "15",
   "IssueDate": "2025-01-01",
   "Paragraph": "113",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2025-en-r&anchor=para_113_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r181": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "15",
   "IssueDate": "2025-01-01",
   "Paragraph": "114",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2025-en-r&anchor=para_114&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r182": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "15",
   "IssueDate": "2025-01-01",
   "Paragraph": "115",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2025-en-r&anchor=para_115&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r183": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "15",
   "IssueDate": "2025-01-01",
   "Paragraph": "116",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2025-en-r&anchor=para_116_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r184": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "15",
   "IssueDate": "2025-01-01",
   "Paragraph": "120",
   "Subparagraph": "b",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2025-en-r&anchor=para_120_b_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r185": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "15",
   "IssueDate": "2025-01-01",
   "Paragraph": "128",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2025-en-r&anchor=para_128_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r186": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "15",
   "IssueDate": "2025-01-01",
   "Paragraph": "128",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2025-en-r&anchor=para_128_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r187": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "33",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&anchor=para_33&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r188": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "47",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&anchor=para_47_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r189": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "47",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&anchor=para_47_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r190": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "53",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&anchor=para_53_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r191": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "53",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&anchor=para_53_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r192": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "53",
   "Subparagraph": "g",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&anchor=para_53_g&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r193": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "53",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&anchor=para_53&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r194": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "58",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&anchor=para_58&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r195": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "59",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&anchor=para_59&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r196": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "94",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&anchor=para_94&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r197": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "97",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&anchor=para_97&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r198": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Section": "Disclosure",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IFRS16_g51-60_TI",
   "URIDate": "2025-03-27"
  },
  "r199": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Section": "Presentation",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IFRS16_g47-50_TI",
   "URIDate": "2025-03-27"
  },
  "r200": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "109",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_109&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r201": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "109A",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_109A&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r202": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "120",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_120&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r203": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "124",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_124&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r204": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "125",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_125&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r205": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "127",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_127&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r206": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "128",
   "Subparagraph": "a",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_128_a_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r207": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "128",
   "Subparagraph": "a",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_128_a_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r208": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "128",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_128_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r209": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "130",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_130&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r210": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "132",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_132_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r211": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "C32",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_C32&doctype=Appendix&subtype=C",
   "URIDate": "2025-03-27"
  },
  "r212": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "44",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_44&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r213": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "Subparagraph": "b",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_b_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r214": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "Subparagraph": "b",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_b_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r215": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r216": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "Subparagraph": "b",
   "Clause": "iv",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_b_iv&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r217": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "Subparagraph": "b",
   "Clause": "v",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_b_v&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r218": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "Subparagraph": "b",
   "Clause": "vi",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_b_vi&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r219": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "Subparagraph": "b",
   "Clause": "vii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_b_vii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r220": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r221": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r222": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r223": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_45&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r224": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "47",
   "Subparagraph": "a",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_47_a_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r225": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "47",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_47_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r226": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "51",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_51_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r227": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "2",
   "IssueDate": "2025-01-01",
   "Paragraph": "51",
   "Subparagraph": "b",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2025-en-r&anchor=para_51_b_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r228": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "3",
   "IssueDate": "2025-01-01",
   "Paragraph": "B64",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2025-en-r&anchor=para_B64&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r229": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "3",
   "IssueDate": "2025-01-01",
   "Paragraph": "B67",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2025-en-r&anchor=para_B67_c&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r230": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "3",
   "IssueDate": "2025-01-01",
   "Paragraph": "B67",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2025-en-r&anchor=para_B67_d&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r231": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "3",
   "IssueDate": "2025-01-01",
   "Paragraph": "B67",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=3&code=ifrs-tx-2025-en-r&anchor=para_B67&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r232": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "5",
   "IssueDate": "2025-01-01",
   "Paragraph": "33",
   "Subparagraph": "b",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2025-en-r&anchor=para_33_b_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r233": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "5",
   "IssueDate": "2025-01-01",
   "Paragraph": "33",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2025-en-r&anchor=para_33_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r234": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "5",
   "IssueDate": "2025-01-01",
   "Paragraph": "38",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2025-en-r&anchor=para_38&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r235": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "5",
   "IssueDate": "2025-01-01",
   "Section": "Presentation and disclosure",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IFRS05_g30-42_TI",
   "URIDate": "2025-03-27"
  },
  "r236": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "10",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_10_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r237": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "10A",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_10A_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r238": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "11B",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_11B_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r239": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "13C",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_13C_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r240": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "13C",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_13C_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r241": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "13C",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_13C_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r242": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "13C",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_13C_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r243": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "13C",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_13C&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r244": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "14",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_14_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r245": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "15",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_15_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r246": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "15",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_15_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r247": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "20",
   "Subparagraph": "a",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_20_a_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r248": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "20",
   "Subparagraph": "a",
   "Clause": "vii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_20_a_vii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r249": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "20",
   "Subparagraph": "a",
   "Clause": "viii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_20_a_viii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r250": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "20",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_20_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r251": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "21C",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_21C&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r252": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "22A",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_22A&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r253": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "23A",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_23A&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r254": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "23B",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_23B_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r255": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "23B",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_23B_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r256": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24A",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24A_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r257": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24A",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24A_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r258": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24A",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24A_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r259": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24A",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24A&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r260": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24B",
   "Subparagraph": "a",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24B_a_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r261": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24B",
   "Subparagraph": "a",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24B_a_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r262": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24B",
   "Subparagraph": "a",
   "Clause": "iv",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24B_a_iv&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r263": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24B",
   "Subparagraph": "a",
   "Clause": "v",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24B_a_v&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r264": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24B",
   "Subparagraph": "b",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24B_b_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r265": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24B",
   "Subparagraph": "b",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24B_b_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r266": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24B",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24B_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r267": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24B",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24B&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r268": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24C",
   "Subparagraph": "a",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24C_a_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r269": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24C",
   "Subparagraph": "b",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24C_b_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r270": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24C",
   "Subparagraph": "b",
   "Clause": "iv",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24C_b_iv&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r271": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24C",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24C&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r272": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24E",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24E_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r273": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "24J",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_24J_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r274": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "25",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_25&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r275": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "28",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_28_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r276": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "31",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_31&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r277": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "33",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_33&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r278": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "34",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_34_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r279": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "34",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_34&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r280": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35F",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35F&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r281": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35G",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35G&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r282": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35H",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35H_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r283": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35H",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35H_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r284": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35H",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35H_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r285": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35H",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35H&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r286": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35I",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35I&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r287": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35J",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35J_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r288": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35J",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35J_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r289": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35K",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35K_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r290": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35K",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35K_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r291": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35K",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35K&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r292": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35L",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35L&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r293": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35M",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35M_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r294": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35M",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35M_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r295": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35M",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35M_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r296": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35M",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35M&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r297": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "36",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_36&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r298": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "39",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_39_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r299": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "39",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_39_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r300": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "42D",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_42D_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r301": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "42D",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_42D_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r302": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "42D",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_42D_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r303": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "42D",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_42D&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r304": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "42E",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_42E_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r305": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "42E",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_42E_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r306": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "42E",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_42E_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r307": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "42E",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_42E_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r308": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "42E",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_42E&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r309": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "42G",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_42G_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r310": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "42G",
   "Subparagraph": "c",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_42G_c_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r311": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "42G",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_42G&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r312": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "42I",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_42I&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r313": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "6",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_6&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r314": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "7",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_7&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r315": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "8",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_8_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r316": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "8",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_8_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r317": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "8",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_8_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r318": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "8",
   "Subparagraph": "h",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_8_h&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r319": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "8",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_8&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r320": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "9",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_9_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r321": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "9",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_9_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r322": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B11E",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B11E&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r323": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B2",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B2_a&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r324": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B51",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B51&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r325": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B52",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B52&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r326": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B8E",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B8E&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r327": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Section": "Credit risk",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IFRS07_g35A-38_TI",
   "URIDate": "2025-03-27"
  },
  "r328": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Section": "Defined terms",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&doctype=Appendix&subtype=A&dita_xref=IFRS07_APPA_TI",
   "URIDate": "2025-03-27"
  },
  "r329": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Section": "Offsetting financial assets and financial liabilities",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IFRS07_g13A-13F_TI",
   "URIDate": "2025-03-27"
  },
  "r330": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Section": "Transfers of financial assets",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IFRS07_g42A-42S_TI",
   "URIDate": "2025-03-27"
  },
  "r331": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "23",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_23_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r332": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "23",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_23_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r333": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "23",
   "Subparagraph": "g",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_23_g&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r334": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "23",
   "Subparagraph": "h",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_23_h&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r335": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "23",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_23&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r336": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "24",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_24_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r337": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "28",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_28_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r338": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "28",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_28_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r339": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "28",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_28_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r340": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "28",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_28_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r341": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "28",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_28&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r342": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "32",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_32&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r343": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "33",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_33_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r344": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "33",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_33_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r345": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "33",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_33&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r346": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Section": "Disclosure",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&doctype=Standard&dita_xref=IFRS08_g20-24_TI",
   "URIDate": "2025-03-27"
  },
  "r347": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "9",
   "IssueDate": "2025-01-01",
   "Paragraph": "3.2.23",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=9&code=ifrs-tx-2025-en-r&anchor=para_3.2.23_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r348": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "9",
   "IssueDate": "2025-01-01",
   "Paragraph": "6.5.11",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=9&code=ifrs-tx-2025-en-r&anchor=para_6.5.11&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r349": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "9",
   "IssueDate": "2025-01-01",
   "Paragraph": "6.5.13",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=9&code=ifrs-tx-2025-en-r&anchor=para_6.5.13_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r350": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "9",
   "IssueDate": "2025-01-01",
   "Paragraph": "6.5.14",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=9&code=ifrs-tx-2025-en-r&anchor=para_6.5.14&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r351": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "9",
   "IssueDate": "2025-01-01",
   "Paragraph": "7.2.34",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=9&code=ifrs-tx-2025-en-r&anchor=para_7.2.34&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r352": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Name": "IFRS",
   "Number": "9",
   "IssueDate": "2025-01-01",
   "Paragraph": "7.2.42",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=9&code=ifrs-tx-2025-en-r&anchor=para_7.2.42&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r353": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2026-01-01",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "20B",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_20B&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r354": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2026-01-01",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "30A",
   "Subparagraph": "b",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_30A_b_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r355": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2026-01-01",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "30B",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_30B&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r356": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "103",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_103&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r357": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "104",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_104&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r358": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "105",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_105_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r359": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "106",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_106&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r360": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "108",
   "Subparagraph": "b",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_108_b_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r361": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "113",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_113_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r362": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "113",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_113_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r363": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "115",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_115_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r364": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "115",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_115_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r365": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "115",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_115_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r366": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "115",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_115&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r367": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "119",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_119&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r368": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "120",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_120&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r369": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "122",
   "Subparagraph": "a",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_122_a_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r370": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "122",
   "Subparagraph": "a",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_122_a_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r371": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "122",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_122_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r372": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "124",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_124_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r373": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "124",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_124_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r374": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "124",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_124&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r375": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "133",
   "Subparagraph": "a",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_133_a_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r376": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "133",
   "Subparagraph": "a",
   "Clause": "iv",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_133_a_iv&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r377": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "139",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_139_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r378": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "160",
   "Subparagraph": "a",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_160_a_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r379": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "160",
   "Subparagraph": "a",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_160_a_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r380": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "160",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_160_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r381": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "160",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_160_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r382": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "160",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_160&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r383": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "162",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_162_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r384": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "166",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_166_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r385": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "166",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_166_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r386": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "168",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_168_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r387": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "169",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_169&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r388": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "176",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_176&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r389": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "182",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_182&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r390": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "192",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_192&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r391": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "194",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_194_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r392": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "194",
   "Subparagraph": "c",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_194_c_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r393": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "194",
   "Subparagraph": "c",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_194_c_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r394": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "194",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_194_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r395": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "194",
   "Subparagraph": "f",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_194_f_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r396": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "194",
   "Subparagraph": "f",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_194_f_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r397": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "194",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_194_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r398": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "197",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_197&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r399": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "200",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_200_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r400": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "200",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_200_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r401": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "200",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_200_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r402": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "200",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_200&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r403": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "204",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_204&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r404": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "206",
   "Subparagraph": "a",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_206_a_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r405": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "206",
   "Subparagraph": "a",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_206_a_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r406": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "206",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_206_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r407": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "207",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_207_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r408": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "207",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_207_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r409": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "207",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_207_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r410": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "207",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_207_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r411": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "207",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_207_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r412": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "207",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_207&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r413": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "208",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_208_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r414": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "208",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_208&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r415": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "211",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_211_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r416": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "218",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_218_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r417": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "223",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_223_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r418": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "223",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_223_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r419": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "227",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_227&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r420": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "229",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_229&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r421": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "230",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_230_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r422": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "230",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_230&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r423": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "231",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_231_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r424": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "231",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_231_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r425": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "231",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_231_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r426": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "231",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_231_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r427": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "231",
   "Subparagraph": "g",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_231_g&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r428": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "231",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_231&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r429": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "24",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_24_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r430": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "24",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_24_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r431": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "246",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_246_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r432": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "250",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_250_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r433": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "250",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_250_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r434": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "250",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_250&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r435": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "254",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_254_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r436": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "254",
   "Subparagraph": "d",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_254_d_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r437": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "254",
   "Subparagraph": "e",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_254_e_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r438": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "254",
   "Subparagraph": "f",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_254_f_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r439": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "254",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_254&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r440": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "255",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_255_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r441": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "255",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_255&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r442": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "257",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_257_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r443": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "257",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_257_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r444": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "257",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_257_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r445": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "257",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_257&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r446": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "258",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_258_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r447": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "259",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_259_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r448": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "259",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_259&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r449": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "263",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_263_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r450": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "263",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_263_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r451": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "263",
   "Subparagraph": "e",
   "Clause": "vi",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_263_e_vi&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r452": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "263",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_263_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r453": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "263",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_263&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r454": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "269",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_269&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r455": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "271",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_271_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r456": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "271",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_271_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r457": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "273",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_273&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r458": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "274",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_274_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r459": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "28",
   "Subparagraph": "a",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_28_a_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r460": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "28",
   "Subparagraph": "a",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_28_a_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r461": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "31",
   "Subparagraph": "b",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r462": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "31",
   "Subparagraph": "b",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r463": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "31",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r464": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "31",
   "Subparagraph": "b",
   "Clause": "iv",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_iv&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r465": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "31",
   "Subparagraph": "b",
   "Clause": "v",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_v&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r466": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "31",
   "Subparagraph": "b",
   "Clause": "vi",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_vi&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r467": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "31",
   "Subparagraph": "b",
   "Clause": "vii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b_vii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r468": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "31",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r469": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "31",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_31&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r470": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "34",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_34_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r471": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "34",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_34_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r472": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "35",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_35&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r473": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "37",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_37&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r474": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "43",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_43&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r475": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "44",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_44_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r476": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "44",
   "Subparagraph": "b",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_44_b_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r477": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "44",
   "Subparagraph": "b",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_44_b_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r478": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "44",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_44_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r479": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "44",
   "Subparagraph": "e",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_44_e_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r480": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "44",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_44_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r481": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "44",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_44&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r482": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_45_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r483": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "46",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_46_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r484": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "49",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_49&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r485": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "51",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_51_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r486": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "56",
   "Subparagraph": "a",
   "Clause": "iv",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_56_a_iv&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r487": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "56",
   "Subparagraph": "a",
   "Clause": "v",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_56_a_v&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r488": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "56",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_56_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r489": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "56A",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_56A&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r490": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "58",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_58&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r491": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "60",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_60_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r492": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "60",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_60_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r493": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "60",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_60_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r494": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "60",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_60&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r495": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "61",
   "Subparagraph": "a",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_61_a_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r496": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "61",
   "Subparagraph": "a",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_61_a_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r497": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "61",
   "Subparagraph": "a",
   "Clause": "iv",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_61_a_iv&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r498": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "61",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_61_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r499": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "61",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_61&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r500": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "62",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_62_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r501": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "62",
   "Subparagraph": "b",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_62_b_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r502": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "62",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_62_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r503": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "62",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_62&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r504": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "64",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_64_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r505": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "64A",
   "Subparagraph": "b",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_64A_b_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r506": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "64B",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_64B&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r507": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "65",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_65&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r508": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "66",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_66_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r509": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "66",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_66_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r510": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "66",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_66_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r511": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "66",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_66&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r512": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "67",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_67&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r513": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "70",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_70&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r514": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "71",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_71_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r515": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "71",
   "Subparagraph": "b",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_71_b_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r516": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "71",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_71_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r517": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "71",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_71&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r518": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "72",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_72_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r519": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "72",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_72_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r520": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "73",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_73_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r521": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "73",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_73&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r522": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "75",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_75_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r523": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "75",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_75_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r524": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "75",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_75_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r525": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "75",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_75_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r526": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "87",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_87&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r527": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "88",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_88_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r528": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "89",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_89_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r529": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "89",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_89&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r530": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "95",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_95_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r531": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "95",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_95_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r532": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "95",
   "Subparagraph": "d",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_95_d_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r533": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "95",
   "Subparagraph": "d",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_95_d_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r534": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "95",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_95&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r535": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "B10",
   "Subparagraph": "a",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_B10_a_ii&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r536": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "B10",
   "Subparagraph": "a",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_B10_a_iii&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r537": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "B10",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_B10_a&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r538": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "B10",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r539": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "B10",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_B10&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r540": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "B13",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_B13&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r541": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "B15",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_B15&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r542": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "B17",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_B17_a&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r543": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "B9",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_B9_f&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r544": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expired 2023-01-01",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "22",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_22&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r545": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expired 2023-01-01",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "36",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_36_c&doctype=Standard&book=b",
   "URIDate": "2025-03-27"
  },
  "r546": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expired 2023-01-01",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "8",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_8_a&doctype=Standard&book=b",
   "URIDate": "2025-03-27"
  },
  "r547": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expired 2023-01-01",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "8",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_8_c&doctype=Standard&book=b",
   "URIDate": "2025-03-27"
  },
  "r548": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2026-01-01",
   "Name": "IFRS",
   "Number": "9",
   "IssueDate": "2025-01-01",
   "Paragraph": "7.2.49",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=9&code=ifrs-tx-2025-en-r&anchor=para_7.2.49&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r549": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "104",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_104&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r550": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "106",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_106_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r551": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "106",
   "Subparagraph": "d",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_106_d_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r552": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "106",
   "Subparagraph": "d",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_106_d_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r553": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "106",
   "Subparagraph": "d",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_106_d_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r554": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "106",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_106_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r555": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "106",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_106&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r556": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "106A",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_106A&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r557": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "112",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_112_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r558": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "117",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_117&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r559": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "125",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_125&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r560": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "134",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_134&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r561": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "136",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_136&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r562": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "137",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_137_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r563": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "16",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_16&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r564": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r565": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r566": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r567": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r568": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r569": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r570": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "l",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_l&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r571": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "m",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_m&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r572": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "n",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_n&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r573": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "o",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_o&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r574": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "p",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_p&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r575": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "55",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_55&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r576": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "56",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_56&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r577": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "61",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_61_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r578": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "61",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_61_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r579": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "61",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_61&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r580": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "7",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_7&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r581": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "78",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_78_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r582": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "79",
   "Subparagraph": "a",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_79_a_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r583": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "79",
   "Subparagraph": "a",
   "Clause": "iii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_79_a_iii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r584": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "79",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_79_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r585": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "79",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_79_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r586": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "79",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_79&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r587": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "81A",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_81A_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r588": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "81A",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_81A_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r589": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "81A",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_81A_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r590": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "81B",
   "Subparagraph": "a",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_81B_a_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r591": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "81B",
   "Subparagraph": "b",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_81B_b_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r592": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "82",
   "Subparagraph": "a",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_82_a_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r593": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "82",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_82_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r594": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "82",
   "Subparagraph": "aa",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_82_aa&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r595": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "82",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_82_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r596": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "82",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_82_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r597": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "90",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_90&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r598": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "91",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_91_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r599": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "91",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_91_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r600": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "91",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_91&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r601": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "92",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_92&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r602": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "98",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_98_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r603": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "98",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_98_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r604": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "98",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_98_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r605": {
   "role": "http://www.xbrl.org/2003/role/disclosureRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "99",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_99&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r606": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "80",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_80_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r607": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "80",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_80_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r608": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "37",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=16&code=ifrs-tx-2025-en-r&anchor=para_37_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r609": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "37",
   "Subparagraph": "g",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=16&code=ifrs-tx-2025-en-r&anchor=para_37_g&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r610": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "138",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_138_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r611": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "138",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_138_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r612": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "138",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_138_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r613": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "142",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_142_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r614": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "142",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_142_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r615": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "142",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_142_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r616": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "142",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_142_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r617": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "142",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_142_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r618": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "142",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_142_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r619": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "147",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_147_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r620": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "24",
   "IssueDate": "2025-01-01",
   "Paragraph": "21",
   "Subparagraph": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=24&code=ifrs-tx-2025-en-r&anchor=para_21_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r621": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "127",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_127&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r622": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "37",
   "IssueDate": "2025-01-01",
   "Paragraph": "66",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&anchor=para_66&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r623": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "37",
   "IssueDate": "2025-01-01",
   "Paragraph": "70",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&anchor=para_70&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r624": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "37",
   "IssueDate": "2025-01-01",
   "Paragraph": "87",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&anchor=para_87&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r625": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "37",
   "IssueDate": "2025-01-01",
   "Section": "Example 10 A court case",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&doctype=Illustrative%20Examples&dita_xref=IAS37_IE_C_ex10_TI",
   "URIDate": "2025-03-27"
  },
  "r626": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "38",
   "IssueDate": "2025-01-01",
   "Paragraph": "119",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2025-en-r&anchor=para_119_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r627": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "14",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_14_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r628": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "17",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_17_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r629": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "17",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_17_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r630": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "17",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_17_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r631": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "44B",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_44B&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r632": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "50",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_50_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r633": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Section": "A Statement of cash flows for an entity other than a financial institution",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&doctype=Illustrative%20Examples&dita_xref=IAS07_IE_A_TI",
   "URIDate": "2025-03-27"
  },
  "r634": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "IG63",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2025-en-r&anchor=para_IG63&doctype=Implementation%20Guidance",
   "URIDate": "2025-03-27"
  },
  "r635": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B10",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r636": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B23",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B23_a&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r637": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B23",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B23_b&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r638": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "B23",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2025-en-r&anchor=para_B23_c&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r639": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r640": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "94",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_94&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r641": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "B11",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_B11_a&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r642": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "B11",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_B11_b&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r643": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "B36",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_B36_a&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r644": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "B36",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_B36_b&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r645": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "B36",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_B36_c&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r646": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "B36",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_B36_d&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r647": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "B36",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_B36_e&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r648": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "B5",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_B5&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r649": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "B6",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_B6&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r650": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "IE60",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_IE60&doctype=Illustrative%20Examples",
   "URIDate": "2025-03-27"
  },
  "r651": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "IE63",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_IE63&doctype=Illustrative%20Examples",
   "URIDate": "2025-03-27"
  },
  "r652": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "15",
   "IssueDate": "2025-01-01",
   "Paragraph": "B89",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2025-en-r&anchor=para_B89_a&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r653": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "15",
   "IssueDate": "2025-01-01",
   "Paragraph": "B89",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=15&code=ifrs-tx-2025-en-r&anchor=para_B89_b&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r654": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "53",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2025-en-r&anchor=para_53&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r655": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "113",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_113_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r656": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "96",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_96_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r657": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "17",
   "IssueDate": "2025-01-01",
   "Paragraph": "96",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_96_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r658": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "13C",
   "Subparagraph": "d",
   "Clause": "i",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_13C_d_i&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r659": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "13C",
   "Subparagraph": "d",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_13C_d_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r660": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "28",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_28_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r661": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "32",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_32&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r662": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35H",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35H&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r663": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35I",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35I_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r664": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35I",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35I_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r665": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35I",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35I_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r666": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35I",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35I_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r667": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35I",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35I&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r668": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35M",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35M&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r669": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "35N",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_35N&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r670": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "40",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_40_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r671": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "6",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_6&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r672": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B11",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B11_a&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r673": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B11",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B11_b&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r674": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B11",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B11&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r675": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B11D",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B11D_a&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r676": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B33",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B33&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r677": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B35",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B35_a&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r678": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B35",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B35_b&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r679": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B35",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B35_c&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r680": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B35",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B35_d&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r681": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B35",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B35_e&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r682": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B35",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B35_f&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r683": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B35",
   "Subparagraph": "g",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B35_g&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r684": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "B35",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_B35&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r685": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "IG14",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_IG14&doctype=Implementation%20Guidance",
   "URIDate": "2025-03-27"
  },
  "r686": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "IG20B",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_IG20B&doctype=Implementation%20Guidance",
   "URIDate": "2025-03-27"
  },
  "r687": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "IG20C",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_IG20C&doctype=Implementation%20Guidance",
   "URIDate": "2025-03-27"
  },
  "r688": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "IG20D",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_IG20D&doctype=Implementation%20Guidance",
   "URIDate": "2025-03-27"
  },
  "r689": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "IG31A",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_IG31A&doctype=Implementation%20Guidance",
   "URIDate": "2025-03-27"
  },
  "r690": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "IG32",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_IG32&doctype=Implementation%20Guidance",
   "URIDate": "2025-03-27"
  },
  "r691": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "IG40B",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_IG40B&doctype=Implementation%20Guidance",
   "URIDate": "2025-03-27"
  },
  "r692": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "IG40D",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_IG40D&doctype=Implementation%20Guidance",
   "URIDate": "2025-03-27"
  },
  "r693": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "23",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_23&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r694": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "28",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_28_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r695": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "28",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_28&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r696": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Name": "IFRS",
   "Number": "8",
   "IssueDate": "2025-01-01",
   "Paragraph": "IG4",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2025-en-r&anchor=para_IG4&doctype=Implementation%20Guidance",
   "URIDate": "2025-03-27"
  },
  "r697": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "103",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_103_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r698": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "103",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_103_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r699": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "115",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_115&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r700": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "193",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_193_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r701": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "193",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_193_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r702": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "208",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_208_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r703": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "208",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_208_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r704": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "208",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_208_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r705": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "251",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_251&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r706": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "64",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_64_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r707": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "66",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_66&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r708": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "70",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_70_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r709": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "70",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_70_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r710": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "70",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_70_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r711": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "70",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_70_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r712": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "70",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_70&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r713": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "71",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_71&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r714": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Effective 2027-01-01",
   "Name": "IFRS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "B9",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=19&code=ifrs-tx-2025-en-r&anchor=para_B9_f&doctype=Appendix&subtype=B",
   "URIDate": "2025-03-27"
  },
  "r715": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Expired 2023-01-01",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "IG25",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2017-en-b&anchor=para_IG25&doctype=Implementation%20Guidance&book=b",
   "URIDate": "2025-03-27"
  },
  "r716": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "102",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_102&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r717": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "103",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_103&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r718": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "108",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_108&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r719": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "78",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_78_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r720": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "82A",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_82A&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r721": {
   "role": "http://www.xbrl.org/2003/role/exampleRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "IG6",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_IG6&doctype=Implementation%20Guidance",
   "URIDate": "2025-03-27"
  },
  "r722": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "12"
  },
  "r723": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "12",
   "Subsection": "b"
  },
  "r724": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "12",
   "Subsection": "b-2"
  },
  "r725": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Exchange Act",
   "Number": "240",
   "Section": "12",
   "Subsection": "d1-1"
  },
  "r726": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 10-K",
   "Number": "249",
   "Section": "310"
  },
  "r727": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Number": "249",
   "Section": "220",
   "Subsection": "f"
  },
  "r728": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "16",
   "Subsection": "J",
   "Paragraph": "a"
  },
  "r729": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "16K"
  },
  "r730": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "16K",
   "Subsection": "b",
   "Paragraph": "1"
  },
  "r731": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "16K",
   "Subsection": "b",
   "Paragraph": "1",
   "Subparagraph": "i"
  },
  "r732": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "16K",
   "Subsection": "b",
   "Paragraph": "1",
   "Subparagraph": "ii"
  },
  "r733": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "16K",
   "Subsection": "b",
   "Paragraph": "1",
   "Subparagraph": "iii"
  },
  "r734": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "16K",
   "Subsection": "b",
   "Paragraph": "2"
  },
  "r735": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "16K",
   "Subsection": "c",
   "Paragraph": "1"
  },
  "r736": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "16K",
   "Subsection": "c",
   "Paragraph": "2"
  },
  "r737": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "16K",
   "Subsection": "c",
   "Paragraph": "2",
   "Subparagraph": "i"
  },
  "r738": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "16K",
   "Subsection": "c",
   "Paragraph": "2",
   "Subparagraph": "ii"
  },
  "r739": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "16K",
   "Subsection": "c",
   "Paragraph": "2",
   "Subparagraph": "iii"
  },
  "r740": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "6",
   "Subsection": "F",
   "Paragraph": "1"
  },
  "r741": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "6",
   "Subsection": "F",
   "Paragraph": "1",
   "Subparagraph": "i"
  },
  "r742": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "6",
   "Subsection": "F",
   "Paragraph": "1",
   "Subparagraph": "i",
   "Sentence": "A"
  },
  "r743": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "6",
   "Subsection": "F",
   "Paragraph": "1",
   "Subparagraph": "i",
   "Sentence": "B"
  },
  "r744": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "6",
   "Subsection": "F",
   "Paragraph": "1",
   "Subparagraph": "i",
   "Sentence": "C"
  },
  "r745": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "6",
   "Subsection": "F",
   "Paragraph": "1",
   "Subparagraph": "i",
   "Sentence": "D"
  },
  "r746": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "6",
   "Subsection": "F",
   "Paragraph": "1",
   "Subparagraph": "i",
   "Sentence": "E"
  },
  "r747": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "6",
   "Subsection": "F",
   "Paragraph": "1",
   "Subparagraph": "ii"
  },
  "r748": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "6",
   "Subsection": "F",
   "Paragraph": "1",
   "Subparagraph": "iii"
  },
  "r749": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 20-F",
   "Section": "6",
   "Subsection": "F",
   "Paragraph": "2"
  },
  "r750": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 40-F",
   "Number": "249",
   "Section": "240",
   "Subsection": "f"
  },
  "r751": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 40-F",
   "Section": "19",
   "Paragraph": "a"
  },
  "r752": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 40-F",
   "Section": "19",
   "Paragraph": "a",
   "Subparagraph": "1"
  },
  "r753": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 40-F",
   "Section": "19",
   "Paragraph": "a",
   "Subparagraph": "1",
   "Sentence": "i"
  },
  "r754": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 40-F",
   "Section": "19",
   "Paragraph": "a",
   "Subparagraph": "1",
   "Sentence": "ii"
  },
  "r755": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 40-F",
   "Section": "19",
   "Paragraph": "a",
   "Subparagraph": "1",
   "Sentence": "iii"
  },
  "r756": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 40-F",
   "Section": "19",
   "Paragraph": "a",
   "Subparagraph": "1",
   "Sentence": "iv"
  },
  "r757": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 40-F",
   "Section": "19",
   "Paragraph": "a",
   "Subparagraph": "1",
   "Sentence": "v"
  },
  "r758": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 40-F",
   "Section": "19",
   "Paragraph": "a",
   "Subparagraph": "2"
  },
  "r759": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 40-F",
   "Section": "19",
   "Paragraph": "a",
   "Subparagraph": "3"
  },
  "r760": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form 40-F",
   "Section": "19",
   "Paragraph": "b"
  },
  "r761": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form N-CSR",
   "Section": "18",
   "Paragraph": "a"
  },
  "r762": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form N-CSR",
   "Section": "18",
   "Paragraph": "a",
   "Subparagraph": "1"
  },
  "r763": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form N-CSR",
   "Section": "18",
   "Paragraph": "a",
   "Subparagraph": "1",
   "Sentence": "i"
  },
  "r764": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form N-CSR",
   "Section": "18",
   "Paragraph": "a",
   "Subparagraph": "1",
   "Sentence": "ii"
  },
  "r765": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form N-CSR",
   "Section": "18",
   "Paragraph": "a",
   "Subparagraph": "1",
   "Sentence": "iii"
  },
  "r766": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form N-CSR",
   "Section": "18",
   "Paragraph": "a",
   "Subparagraph": "1",
   "Sentence": "iv"
  },
  "r767": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form N-CSR",
   "Section": "18",
   "Paragraph": "a",
   "Subparagraph": "1",
   "Sentence": "v"
  },
  "r768": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form N-CSR",
   "Section": "18",
   "Paragraph": "a",
   "Subparagraph": "2"
  },
  "r769": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form N-CSR",
   "Section": "18",
   "Paragraph": "a",
   "Subparagraph": "3"
  },
  "r770": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Form N-CSR",
   "Section": "18",
   "Paragraph": "b"
  },
  "r771": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Forms 10-K, 10-Q, 20-F",
   "Number": "240",
   "Section": "13",
   "Subsection": "a-1"
  },
  "r772": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v"
  },
  "r773": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "1"
  },
  "r774": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "ii"
  },
  "r775": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "iii"
  },
  "r776": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "iii",
   "Sentence": "B",
   "Clause": "1",
   "Subclause": "ii"
  },
  "r777": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "iii",
   "Sentence": "C",
   "Clause": "1",
   "Subclause": "i"
  },
  "r778": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "iii",
   "Sentence": "C",
   "Clause": "1",
   "Subclause": "ii"
  },
  "r779": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "iii",
   "Sentence": "C",
   "Clause": "1",
   "Subclause": "iii"
  },
  "r780": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "iii",
   "Sentence": "C",
   "Clause": "1",
   "Subclause": "iv"
  },
  "r781": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "iii",
   "Sentence": "C",
   "Clause": "1",
   "Subclause": "v"
  },
  "r782": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "iii",
   "Sentence": "C",
   "Clause": "1",
   "Subclause": "vi"
  },
  "r783": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "iv"
  },
  "r784": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "vi"
  },
  "r785": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "3"
  },
  "r786": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "4"
  },
  "r787": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "5",
   "Subparagraph": "i"
  },
  "r788": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "5",
   "Subparagraph": "ii"
  },
  "r789": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "5",
   "Subparagraph": "iii"
  },
  "r790": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "5",
   "Subparagraph": "iv"
  },
  "r791": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "6"
  },
  "r792": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "6",
   "Subparagraph": "i"
  },
  "r793": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "w"
  },
  "r794": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "w",
   "Paragraph": "1"
  },
  "r795": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "w",
   "Paragraph": "1",
   "Subparagraph": "i"
  },
  "r796": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "w",
   "Paragraph": "1",
   "Subparagraph": "i",
   "Sentence": "A"
  },
  "r797": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "w",
   "Paragraph": "1",
   "Subparagraph": "i",
   "Sentence": "B"
  },
  "r798": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "w",
   "Paragraph": "1",
   "Subparagraph": "i",
   "Sentence": "C"
  },
  "r799": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "w",
   "Paragraph": "1",
   "Subparagraph": "i",
   "Sentence": "D"
  },
  "r800": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "w",
   "Paragraph": "1",
   "Subparagraph": "i",
   "Sentence": "E"
  },
  "r801": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "w",
   "Paragraph": "1",
   "Subparagraph": "ii"
  },
  "r802": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "w",
   "Paragraph": "1",
   "Subparagraph": "iii"
  },
  "r803": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "w",
   "Paragraph": "2"
  },
  "r804": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "x",
   "Paragraph": "1"
  },
  "r805": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "x",
   "Paragraph": "2"
  },
  "r806": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "x",
   "Paragraph": "2",
   "Subparagraph": "ii",
   "Sentence": "A"
  },
  "r807": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "x",
   "Paragraph": "2",
   "Subparagraph": "ii",
   "Sentence": "C"
  },
  "r808": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "x",
   "Paragraph": "2",
   "Subparagraph": "ii",
   "Sentence": "D"
  },
  "r809": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "x",
   "Paragraph": "2",
   "Subparagraph": "ii",
   "Sentence": "E"
  },
  "r810": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "402",
   "Subsection": "x",
   "Paragraph": "2",
   "Subparagraph": "ii",
   "Sentence": "F"
  },
  "r811": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "408",
   "Subsection": "a"
  },
  "r812": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "408",
   "Subsection": "a",
   "Paragraph": "1"
  },
  "r813": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "408",
   "Subsection": "a",
   "Paragraph": "2",
   "Subparagraph": "A"
  },
  "r814": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "408",
   "Subsection": "a",
   "Paragraph": "2",
   "Subparagraph": "B"
  },
  "r815": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "408",
   "Subsection": "a",
   "Paragraph": "2",
   "Subparagraph": "C"
  },
  "r816": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "408",
   "Subsection": "a",
   "Paragraph": "2",
   "Subparagraph": "D"
  },
  "r817": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Number": "229",
   "Section": "408",
   "Subsection": "b",
   "Paragraph": "1"
  },
  "r818": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "106"
  },
  "r819": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "106",
   "Subsection": "b",
   "Paragraph": "1"
  },
  "r820": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "106",
   "Subsection": "b",
   "Paragraph": "1",
   "Subparagraph": "i"
  },
  "r821": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "106",
   "Subsection": "b",
   "Paragraph": "1",
   "Subparagraph": "ii"
  },
  "r822": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "106",
   "Subsection": "b",
   "Paragraph": "1",
   "Subparagraph": "iii"
  },
  "r823": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "106",
   "Subsection": "b",
   "Paragraph": "2"
  },
  "r824": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "106",
   "Subsection": "c",
   "Paragraph": "1"
  },
  "r825": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "106",
   "Subsection": "c",
   "Paragraph": "2"
  },
  "r826": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "106",
   "Subsection": "c",
   "Paragraph": "2",
   "Subparagraph": "i"
  },
  "r827": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "106",
   "Subsection": "c",
   "Paragraph": "2",
   "Subparagraph": "ii"
  },
  "r828": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "106",
   "Subsection": "c",
   "Paragraph": "2",
   "Subparagraph": "iii"
  },
  "r829": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "402",
   "Number": "229",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "iii",
   "Sentence": "C",
   "Clause": "1"
  },
  "r830": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "iii",
   "Sentence": "A",
   "Number": "229"
  },
  "r831": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "iii",
   "Sentence": "B",
   "Clause": "1",
   "Number": "229"
  },
  "r832": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-K",
   "Section": "402",
   "Subsection": "v",
   "Paragraph": "2",
   "Subparagraph": "iii",
   "Sentence": "B",
   "Clause": "1",
   "Subclause": "i",
   "Number": "229"
  },
  "r833": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Regulation S-T",
   "Number": "232",
   "Section": "405"
  },
  "r834": {
   "role": "http://www.xbrl.org/2003/role/presentationRef",
   "Publisher": "SEC",
   "Name": "Securities Act",
   "Number": "230",
   "Section": "405"
  },
  "r835": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "80",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_80&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r836": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "81",
   "Subparagraph": "g",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_81_g&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r837": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "12",
   "IssueDate": "2025-01-01",
   "Paragraph": "81",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=12&code=ifrs-tx-2025-en-r&anchor=para_81&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r838": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "37",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=16&code=ifrs-tx-2025-en-r&anchor=para_37&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r839": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "73",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=16&code=ifrs-tx-2025-en-r&anchor=para_73_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r840": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "16",
   "IssueDate": "2025-01-01",
   "Paragraph": "73",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=16&code=ifrs-tx-2025-en-r&anchor=para_73_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r841": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "135",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_135_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r842": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "138",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_138_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r843": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "141",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_141_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r844": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "141",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_141&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r845": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "142",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_142&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r846": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "144",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_144&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r847": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "158",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_158&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r848": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "5",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_5&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r849": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "57",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_57_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r850": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "8",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_8&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r851": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "19",
   "IssueDate": "2025-01-01",
   "Paragraph": "9",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2025-en-r&anchor=para_9&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r852": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "36",
   "IssueDate": "2025-01-01",
   "Paragraph": "127",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=36&code=ifrs-tx-2025-en-r&anchor=para_127&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r853": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "37",
   "IssueDate": "2025-01-01",
   "Paragraph": "84",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=37&code=ifrs-tx-2025-en-r&anchor=para_84&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r854": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "38",
   "IssueDate": "2025-01-01",
   "Paragraph": "118",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2025-en-r&anchor=para_118_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r855": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "38",
   "IssueDate": "2025-01-01",
   "Paragraph": "118",
   "Subparagraph": "e",
   "Clause": "ii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2025-en-r&anchor=para_118_e_ii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r856": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "38",
   "IssueDate": "2025-01-01",
   "Paragraph": "118",
   "Subparagraph": "e",
   "Clause": "iv",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2025-en-r&anchor=para_118_e_iv&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r857": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "38",
   "IssueDate": "2025-01-01",
   "Paragraph": "118",
   "Subparagraph": "e",
   "Clause": "vii",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2025-en-r&anchor=para_118_e_vii&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r858": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "38",
   "IssueDate": "2025-01-01",
   "Paragraph": "118",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2025-en-r&anchor=para_118&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r859": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "38",
   "IssueDate": "2025-01-01",
   "Paragraph": "119",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=38&code=ifrs-tx-2025-en-r&anchor=para_119&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r860": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "40",
   "IssueDate": "2025-01-01",
   "Paragraph": "79",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=40&code=ifrs-tx-2025-en-r&anchor=para_79_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r861": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "41",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "f",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=41&code=ifrs-tx-2025-en-r&anchor=para_54_f&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r862": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "14",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_14&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r863": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "16",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_16&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r864": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "17",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_17&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r865": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "20",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_20_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r866": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "20",
   "Subparagraph": "b",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_20_b&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r867": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "20",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_20&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r868": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IAS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "45",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2025-en-r&anchor=para_45&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r869": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r870": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IFRS",
   "Number": "13",
   "IssueDate": "2025-01-01",
   "Paragraph": "93",
   "Subparagraph": "h",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=13&code=ifrs-tx-2025-en-r&anchor=para_93_h&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r871": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IFRS",
   "Number": "5",
   "IssueDate": "2025-01-01",
   "Paragraph": "38",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2025-en-r&anchor=para_38&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r872": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "32",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_32&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r873": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "39",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_39&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r874": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "41",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_41&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r875": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Name": "IFRS",
   "Number": "7",
   "IssueDate": "2025-01-01",
   "Paragraph": "7",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_7&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r876": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "10",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_10_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r877": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "102",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_102&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r878": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "103",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_103&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r879": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "106",
   "Subparagraph": "d",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_106_d&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r880": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "112",
   "Subparagraph": "c",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_112_c&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r881": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "117",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_117&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r882": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "54",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_54_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r883": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "55",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_55&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r884": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "78",
   "Subparagraph": "e",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_78_e&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r885": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "78",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_78&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r886": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "79",
   "Subparagraph": "a",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_79_a&doctype=Standard",
   "URIDate": "2025-03-27"
  },
  "r887": {
   "role": "http://www.xbrl.org/2009/role/commonPracticeRef",
   "Note": "Expiry date 2027-01-01",
   "Name": "IAS",
   "Number": "1",
   "IssueDate": "2025-01-01",
   "Paragraph": "85",
   "URI": "https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_85&doctype=Standard",
   "URIDate": "2025-03-27"
  }
 }
}
