v3.25.4
Risk Management - ECL under 100% weighted scenarios for modelled portfolios (Details)
£ in Millions
 12 Months Ended
Dec. 31, 2025
GBP (£)
economic_scenario
Dec. 31, 2024
GBP (£)
Dec. 31, 2023
GBP (£)
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Expected credit loss rate 100.00%    
Financial assets £ (1,232,975) £ (1,204,773)  
Retail mortgages      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Expected credit loss rate 0.70% 0.80%  
Financial assets £ (4,952) £ (4,956)  
Retail mortgages | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets £ (4,952) £ (4,956)  
Retail credit cards      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Expected credit loss rate 11.20% 11.50%  
Financial assets £ (20,527) £ (19,749)  
Retail credit cards | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets £ (20,527) £ (19,749)  
Corporate loans      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Expected credit loss rate 0.80% 0.70%  
Financial assets £ (121,179) £ (116,204)  
Corporate loans | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets (121,179) (116,204)  
Accumulated impairment      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 4,034 3,860  
Accumulated impairment | ECL collectively assessed      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 3,451 3,712  
Accumulated impairment | Retail mortgages      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 33 41 £ 360
Accumulated impairment | Retail mortgages | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 33 41  
Accumulated impairment | Retail credit cards      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 2,586 2,557 2,776
Accumulated impairment | Retail credit cards | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 2,586 2,557  
Accumulated impairment | Corporate loans      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 966 791 £ 836
Accumulated impairment | Corporate loans | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets £ 966 791  
Credit risk      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Number of economic scenarios | economic_scenario 5    
Credit risk | Accumulated impairment | Retail mortgages | ECL collectively assessed | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets £ 2 5  
Credit risk | Accumulated impairment | Retail credit cards | ECL collectively assessed | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 2,817 2,981  
Credit risk | Accumulated impairment | Corporate loans | ECL collectively assessed | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets £ 632 726  
Baseline | Corporate loans      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Weighted expected credit loss, uplift percentage 5.30%    
Baseline | Accumulated impairment      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Weighted expected credit loss, uplift percentage 0.80%    
Baseline | Accumulated impairment | Retail mortgages | ECL collectively assessed | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets £ 2 5  
Baseline | Accumulated impairment | Retail credit cards | ECL collectively assessed | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 2,821 2,983  
Baseline | Accumulated impairment | Corporate loans | ECL collectively assessed | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 600 690  
Downside 2 | Accumulated impairment | Retail mortgages | ECL collectively assessed | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 2 5  
Downside 2 | Accumulated impairment | Retail credit cards | ECL collectively assessed | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets 3,092 3,163  
Downside 2 | Accumulated impairment | Corporate loans | ECL collectively assessed | Financial assets at amortised cost      
Disclosure of nature and extent of risks arising from financial instruments [line items]      
Financial assets £ 1,076 £ 1,156