Subordinated liabilities - Disclosure of undated subordinated liabilities (Details) £ in Millions	Dec. 31, 2025 GBP (£)	Dec. 31, 2025 JPY (¥)	Dec. 31, 2024 GBP (£)
Disclosure of detailed information about borrowings [line items]
Notional contract amount	£ 100,079,291		£ 83,792,768
Undated subordinated liabilities	£ 127		134
6.125% Undated Subordinated Notes \| Barclays Bank PLC
Disclosure of detailed information about borrowings [line items]
Interest rate	6.125%	6.125%
Undated subordinated liabilities	£ 35		35
5.03% Reverse Dual Currency Undated Subordinated Loan (JPY 8,000m) \| Barclays Bank PLC
Disclosure of detailed information about borrowings [line items]
Interest rate	5.03%	5.03%
Notional contract amount \| ¥		¥ 8,000,000,000
Undated subordinated liabilities	£ 37		40
5% Reverse Dual Currency Undated Subordinated Loan (JPY 12,000m) \| Barclays Bank PLC
Disclosure of detailed information about borrowings [line items]
Interest rate	5.00%	5.00%
Notional contract amount \| ¥		¥ 12,000,000,000
Undated subordinated liabilities	£ 55		£ 59

The interest rate on borrowings. [Refer: Borrowings]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

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.

+ References

No definition available.

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- Definition

The nominal or face amount of a financial instrument, used to calculate payments made on that instrument.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Note Expiry date 2027-01-01
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- Definition

The amount of subordinated liabilities that do not have a specified repayment date. [Refer: Subordinated liabilities]

+ References

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