v3.26.1
Allowance for expected credit losses - Narrative (Details) - Allowance for expected credit losses - GBP (£)
£ in Millions
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Judgemental adjustments £m      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses £ 140 £ 224  
UK mortgages | Judgemental adjustments £m      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses 67 108  
UK mortgages | Judgemental adjustments £m | Repossession risk      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses 67 85  
UK mortgages | Judgemental adjustments £m | Mortgage accounts in specific segments      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses 0 13  
Credit cards | Judgemental adjustments £m      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses 56 63  
Credit cards | Judgemental adjustments £m | Extension of modelled lifetime on retail revolving products      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses 49 49  
Other Retail | Judgemental adjustments £m      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses 73 75  
Other Retail | Judgemental adjustments £m | Extension of modelled lifetime on retail revolving products      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses 9 9  
Other Retail | Judgemental adjustments £m | Loss given default alignment (LGD)      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses 37 25  
Commercial Banking | Judgemental adjustments £m      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses (56) (22)  
Commercial Banking | Judgemental adjustments £m | Loss given default alignment (LGD)      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses 50 50  
Commercial Banking | Judgemental adjustments £m | Corporate insolvency rates      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses (106) (122)  
Commercial Banking | Judgemental adjustments £m | Global tariff and political disruption risks      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses 0 50  
Motor finance | Residual value impairment and voluntary terminations      
Schedule Of Allowance Account For Credit Losses Of Financial Assets [Line Items]      
Allowance for expected credit losses £ 250 £ 243 £ 211