v3.25.4
Risk Management - Disclosure of management adjustments to models for impairment of assets held for sale (Details) - GBP (£)
£ in Millions
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances £ (1,232,975) £ (1,204,773)  
Proportion of Management adjustments to total impairment allowance 4.90% (0.80%)  
Non-current assets/liabilities held for sale      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Proportion of Management adjustments to total impairment allowance 2.10% 6.70%  
Accumulated impairment      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances £ 4,034 £ 3,860  
Accumulated impairment | Total impairment allowance      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 4,034 3,860  
Accumulated impairment | Impairment allowance pre management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 3,835 3,889  
Accumulated impairment | Management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 199 (29)  
Accumulated impairment | Economic uncertainty adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 81 0  
Accumulated impairment | Other adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 118 (29)  
Accumulated impairment | Non-current assets/liabilities held for sale | Total impairment allowance      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 240 496  
Accumulated impairment | Non-current assets/liabilities held for sale | Impairment allowance pre management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 235 463  
Accumulated impairment | Non-current assets/liabilities held for sale | Management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 5 33  
Accumulated impairment | Non-current assets/liabilities held for sale | Economic uncertainty adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 5 0  
Accumulated impairment | Non-current assets/liabilities held for sale | Other adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 33  
Retail credit cards      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances £ (20,527) £ (19,749)  
Proportion of Management adjustments to total impairment allowance 4.50% (0.90%)  
Retail credit cards | Non-current assets/liabilities held for sale | American Airlines Portfolio      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances £ (5,755) £ (5,970)  
Proportion of Management adjustments to total impairment allowance 2.10% 0.00%  
Retail credit cards | Non-current assets/liabilities held for sale | German Consumer Finance portfolio      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances £ 0 £ (2,192)  
Proportion of Management adjustments to total impairment allowance 0.00% 13.70%  
Retail credit cards | Accumulated impairment      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances £ 2,586 £ 2,557 £ 2,776
Retail credit cards | Accumulated impairment | Total impairment allowance      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 2,623 2,607  
Retail credit cards | Accumulated impairment | Impairment allowance pre management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 2,505 2,630  
Retail credit cards | Accumulated impairment | Management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 118 (23)  
Retail credit cards | Accumulated impairment | Economic uncertainty adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 31 0  
Retail credit cards | Accumulated impairment | Other adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 87 (23)  
Retail credit cards | Accumulated impairment | Non-current assets/liabilities held for sale | American Airlines Portfolio      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 233 271  
Retail credit cards | Accumulated impairment | Non-current assets/liabilities held for sale | American Airlines Portfolio | Total impairment allowance      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 237 277  
Retail credit cards | Accumulated impairment | Non-current assets/liabilities held for sale | American Airlines Portfolio | Impairment allowance pre management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 232 277  
Retail credit cards | Accumulated impairment | Non-current assets/liabilities held for sale | American Airlines Portfolio | Management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 5 0  
Retail credit cards | Accumulated impairment | Non-current assets/liabilities held for sale | American Airlines Portfolio | Economic uncertainty adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 5 0  
Retail credit cards | Accumulated impairment | Non-current assets/liabilities held for sale | American Airlines Portfolio | Other adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 0  
Retail credit cards | Accumulated impairment | Non-current assets/liabilities held for sale | German Consumer Finance portfolio      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 116  
Retail credit cards | Accumulated impairment | Non-current assets/liabilities held for sale | German Consumer Finance portfolio | Total impairment allowance      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 117  
Retail credit cards | Accumulated impairment | Non-current assets/liabilities held for sale | German Consumer Finance portfolio | Impairment allowance pre management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 101  
Retail credit cards | Accumulated impairment | Non-current assets/liabilities held for sale | German Consumer Finance portfolio | Management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 16  
Retail credit cards | Accumulated impairment | Non-current assets/liabilities held for sale | German Consumer Finance portfolio | Economic uncertainty adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 0  
Retail credit cards | Accumulated impairment | Non-current assets/liabilities held for sale | German Consumer Finance portfolio | Other adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 16  
Retail other      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances £ (4,128) £ (3,918)  
Proportion of Management adjustments to total impairment allowance (3.00%) 11.10%  
Retail other | Non-current assets/liabilities held for sale | German Consumer Finance portfolio      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances £ 0 £ (1,328)  
Proportion of Management adjustments to total impairment allowance 0.00% 17.50%  
Retail other | Accumulated impairment      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances £ 32 £ 31 45
Retail other | Accumulated impairment | Total impairment allowance      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 33 36  
Retail other | Accumulated impairment | Impairment allowance pre management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 34 32  
Retail other | Accumulated impairment | Management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances (1) 4  
Retail other | Accumulated impairment | Economic uncertainty adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 0  
Retail other | Accumulated impairment | Other adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances (1) 4  
Retail other | Accumulated impairment | Non-current assets/liabilities held for sale | German Consumer Finance portfolio      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 97  
Retail other | Accumulated impairment | Non-current assets/liabilities held for sale | German Consumer Finance portfolio | Total impairment allowance      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 97  
Retail other | Accumulated impairment | Non-current assets/liabilities held for sale | German Consumer Finance portfolio | Impairment allowance pre management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 80  
Retail other | Accumulated impairment | Non-current assets/liabilities held for sale | German Consumer Finance portfolio | Management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 17  
Retail other | Accumulated impairment | Non-current assets/liabilities held for sale | German Consumer Finance portfolio | Economic uncertainty adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 0  
Retail other | Accumulated impairment | Non-current assets/liabilities held for sale | German Consumer Finance portfolio | Other adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 17  
Corporate loans      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances £ (121,179) £ (116,204)  
Proportion of Management adjustments to total impairment allowance 5.50% (0.50%)  
Corporate loans | Non-current assets/liabilities held for sale | American Airlines Portfolio      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances £ (46) £ (54)  
Proportion of Management adjustments to total impairment allowance 0.00% 0.00%  
Corporate loans | Accumulated impairment      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances £ 966 £ 791 £ 836
Corporate loans | Accumulated impairment | Total impairment allowance      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 1,326 1,156  
Corporate loans | Accumulated impairment | Impairment allowance pre management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 1,253 1,162  
Corporate loans | Accumulated impairment | Management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 73 (6)  
Corporate loans | Accumulated impairment | Economic uncertainty adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 49 0  
Corporate loans | Accumulated impairment | Other adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 24 (6)  
Corporate loans | Accumulated impairment | Non-current assets/liabilities held for sale | American Airlines Portfolio      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 3 5  
Corporate loans | Accumulated impairment | Non-current assets/liabilities held for sale | American Airlines Portfolio | Total impairment allowance      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 3 5  
Corporate loans | Accumulated impairment | Non-current assets/liabilities held for sale | American Airlines Portfolio | Impairment allowance pre management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 3 5  
Corporate loans | Accumulated impairment | Non-current assets/liabilities held for sale | American Airlines Portfolio | Management adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 0  
Corporate loans | Accumulated impairment | Non-current assets/liabilities held for sale | American Airlines Portfolio | Economic uncertainty adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances 0 0  
Corporate loans | Accumulated impairment | Non-current assets/liabilities held for sale | American Airlines Portfolio | Other adjustments      
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]      
Loans and advances £ 0 £ 0