v3.26.1
Fair values of financial assets and liabilities - Schedule of Financial Assets Carried at Fair Value by Valuation Hierarchy (Details) - GBP (£)
£ in Millions
Jun. 30, 2026
Dec. 31, 2025
Disclosure of fair value measurement of assets [line items]    
Loans and advances to customers £ 470,268 £ 461,504
Debt securities 15,128 11,983
Financial assets at fair value through profit or loss 1,761 2,279
Derivative financial instruments 3,088 3,260
Total financial assets carried at fair value 45,214 41,796
Level 1 £m    
Disclosure of fair value measurement of assets [line items]    
Financial assets at fair value through profit or loss 296 281
Derivative financial instruments 0 0
Total financial assets carried at fair value 25,647 24,421
Level 2 £m    
Disclosure of fair value measurement of assets [line items]    
Financial assets at fair value through profit or loss 1,216 1,711
Derivative financial instruments 3,088 3,260
Total financial assets carried at fair value 19,269 17,038
Level 3 £m    
Disclosure of fair value measurement of assets [line items]    
Financial assets at fair value through profit or loss 249 287
Derivative financial instruments 0 0
Total financial assets carried at fair value 298 337
Financial assets at fair value through profit or loss    
Disclosure of fair value measurement of assets [line items]    
Loans and advances to customers 1,453 1,993
Debt securities 7 0
Equity shares 301 286
Financial assets at fair value through profit or loss | Level 1 £m    
Disclosure of fair value measurement of assets [line items]    
Loans and advances to customers 0 0
Debt securities 0 0
Equity shares 296 281
Financial assets at fair value through profit or loss | Level 2 £m    
Disclosure of fair value measurement of assets [line items]    
Loans and advances to customers 1,216 1,711
Debt securities 0 0
Equity shares 0 0
Financial assets at fair value through profit or loss | Level 3 £m    
Disclosure of fair value measurement of assets [line items]    
Loans and advances to customers 237 282
Debt securities 7 0
Equity shares 5 5
Financial assets at fair value through other comprehensive income    
Disclosure of fair value measurement of assets [line items]    
Debt securities 40,365 36,257
Financial assets at fair value through other comprehensive income | Level 1 £m    
Disclosure of fair value measurement of assets [line items]    
Debt securities 25,351 24,140
Financial assets at fair value through other comprehensive income | Level 2 £m    
Disclosure of fair value measurement of assets [line items]    
Debt securities 14,965 12,067
Financial assets at fair value through other comprehensive income | Level 3 £m    
Disclosure of fair value measurement of assets [line items]    
Debt securities £ 49 £ 50