v3.26.1
Credit Risk - Disclosure of Base Expected Credit Losses to Probability Weighted Estimated Credit Losses (Details) - GBP (£)
£ in Millions
Jun. 30, 2026
Dec. 31, 2025
Disclosure of credit risk exposure [line items]    
Exposure £ 240,406 £ 202,609
Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Exposure (802) (729)
Upside    
Disclosure of credit risk exposure [line items]    
Exposure 338,669 293,493
Upside | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 810 730
Upside | Retail & Business Banking    
Disclosure of credit risk exposure [line items]    
Exposure 242,700 201,290
Upside | Retail & Business Banking | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 423 357
Upside | Mortgages    
Disclosure of credit risk exposure [line items]    
Exposure - of which: mortgages 217,496 180,339
Upside | Mortgages | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 90 87
Upside | Consumer Finance    
Disclosure of credit risk exposure [line items]    
Exposure 4,988 4,979
Upside | Consumer Finance | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 66 62
Upside | Corporate & Commercial Banking    
Disclosure of credit risk exposure [line items]    
Exposure 29,135 27,361
Upside | Corporate & Commercial Banking | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 321 311
Upside | Corporate Centre    
Disclosure of credit risk exposure [line items]    
Exposure 61,846 59,863
Upside | Corporate Centre | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 0 0
Base case    
Disclosure of credit risk exposure [line items]    
Exposure 338,669 293,493
Base case | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 851 761
Base case | Retail & Business Banking    
Disclosure of credit risk exposure [line items]    
Exposure 242,700 201,290
Base case | Retail & Business Banking | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 452 381
Base case | Mortgages    
Disclosure of credit risk exposure [line items]    
Exposure - of which: mortgages 217,496 180,339
Base case | Mortgages | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 106 100
Base case | Consumer Finance    
Disclosure of credit risk exposure [line items]    
Exposure 4,988 4,979
Base case | Consumer Finance | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 66 62
Base case | Corporate & Commercial Banking    
Disclosure of credit risk exposure [line items]    
Exposure 29,135 27,361
Base case | Corporate & Commercial Banking | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 333 318
Base case | Corporate Centre    
Disclosure of credit risk exposure [line items]    
Exposure 61,846 59,863
Base case | Corporate Centre | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 0 0
Downside 1    
Disclosure of credit risk exposure [line items]    
Exposure 338,669 293,493
Downside 1 | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 944 899
Downside 1 | Retail & Business Banking    
Disclosure of credit risk exposure [line items]    
Exposure 242,700 201,290
Downside 1 | Retail & Business Banking | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 523 483
Downside 1 | Mortgages    
Disclosure of credit risk exposure [line items]    
Exposure - of which: mortgages 217,496 180,339
Downside 1 | Mortgages | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 150 177
Downside 1 | Consumer Finance    
Disclosure of credit risk exposure [line items]    
Exposure 4,988 4,979
Downside 1 | Consumer Finance | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 68 64
Downside 1 | Corporate & Commercial Banking    
Disclosure of credit risk exposure [line items]    
Exposure 29,135 27,361
Downside 1 | Corporate & Commercial Banking | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 353 352
Downside 1 | Corporate Centre    
Disclosure of credit risk exposure [line items]    
Exposure 61,846 59,863
Downside 1 | Corporate Centre | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 0 0
Downside 2    
Disclosure of credit risk exposure [line items]    
Exposure 338,669 293,493
Downside 2 | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 1,198 1,119
Downside 2 | Retail & Business Banking    
Disclosure of credit risk exposure [line items]    
Exposure 242,700 201,290
Downside 2 | Retail & Business Banking | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 745 689
Downside 2 | Mortgages    
Disclosure of credit risk exposure [line items]    
Exposure - of which: mortgages 217,496 180,339
Downside 2 | Mortgages | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 330 366
Downside 2 | Consumer Finance    
Disclosure of credit risk exposure [line items]    
Exposure 4,988 4,979
Downside 2 | Consumer Finance | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 67 64
Downside 2 | Corporate & Commercial Banking    
Disclosure of credit risk exposure [line items]    
Exposure 29,135 27,361
Downside 2 | Corporate & Commercial Banking | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 386 366
Downside 2 | Corporate Centre    
Disclosure of credit risk exposure [line items]    
Exposure 61,846 59,863
Downside 2 | Corporate Centre | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 0 0
Weighted    
Disclosure of credit risk exposure [line items]    
Exposure 338,669 293,493
Weighted | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 889 812
Weighted | Retail & Business Banking    
Disclosure of credit risk exposure [line items]    
Exposure 242,700 201,290
Weighted | Retail & Business Banking | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 487 426
Weighted | Mortgages    
Disclosure of credit risk exposure [line items]    
Exposure - of which: mortgages 217,496 180,339
Weighted | Mortgages | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 136 137
Weighted | Consumer Finance    
Disclosure of credit risk exposure [line items]    
Exposure 4,988 4,979
Weighted | Consumer Finance | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 67 63
Weighted | Corporate & Commercial Banking    
Disclosure of credit risk exposure [line items]    
Exposure 29,135 27,361
Weighted | Corporate & Commercial Banking | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets 335 323
Weighted | Corporate Centre    
Disclosure of credit risk exposure [line items]    
Exposure 61,846 59,863
Weighted | Corporate Centre | Accumulated impairment    
Disclosure of credit risk exposure [line items]    
Financial assets £ 0 £ 0