v3.26.1
Fair value of financial instruments - Level 3 assets and liabilities held at fair value disaggregated by product type (Details) - GBP (£)
£ in Millions
Jun. 30, 2026
Dec. 31, 2025
Disclosure of detailed information about financial instruments [line items]    
Trading portfolio assets £ 210,102 £ 190,061
Financial assets at fair value through the income statement 213,100 186,857
Derivative financial assets 303,602 252,459
Financial assets at fair value through other comprehensive income 83,012 74,394
Trading portfolio liabilities (78,405) (57,737)
Financial liabilities designated at fair value (321,925) (294,108)
Derivative financial instruments (291,785) (240,808)
Significant unobservable inputs (Level 3)    
Disclosure of detailed information about financial instruments [line items]    
Trading portfolio assets 8,778 10,347
Financial assets at fair value through the income statement 5,025 8,577
Derivative financial assets 1,976 1,712
Financial assets at fair value through other comprehensive income 2,441 3,099
Investment property 42 43
Total assets 18,262 23,778
Trading portfolio liabilities (79) (87)
Financial liabilities designated at fair value (2,498) (4,874)
Derivative financial instruments (2,855) (3,065)
Total liabilities (5,432) (8,026)
Significant unobservable inputs (Level 3) | Loans    
Disclosure of detailed information about financial instruments [line items]    
Trading portfolio assets 3,156 5,667
Financial assets at fair value through the income statement 2,979 5,990
Financial assets at fair value through other comprehensive income 2,192 2,235
Total assets 8,327 13,892
Significant unobservable inputs (Level 3) | Corporate debt    
Disclosure of detailed information about financial instruments [line items]    
Trading portfolio assets 1,873 1,849
Financial assets at fair value through the income statement 465 905
Financial assets at fair value through other comprehensive income 227 25
Total assets 2,565 2,779
Trading portfolio liabilities (46) (36)
Total liabilities (46) (36)
Significant unobservable inputs (Level 3) | Asset backed securities    
Disclosure of detailed information about financial instruments [line items]    
Trading portfolio assets 1,670 874
Financial assets at fair value through the income statement 271 188
Financial assets at fair value through other comprehensive income 11 756
Total assets 1,952 1,818
Significant unobservable inputs (Level 3) | Government and Government sponsored debt    
Disclosure of detailed information about financial instruments [line items]    
Trading portfolio assets 1,342 1,513
Financial assets at fair value through the income statement 33 33
Financial assets at fair value through other comprehensive income 7 79
Total assets 1,382 1,625
Trading portfolio liabilities (4) (34)
Total liabilities (4) (34)
Significant unobservable inputs (Level 3) | Private equity investments    
Disclosure of detailed information about financial instruments [line items]    
Financial assets at fair value through the income statement 1,183 1,260
Financial assets at fair value through other comprehensive income 4 4
Total assets 1,187 1,264
Financial liabilities designated at fair value (20) (20)
Total liabilities (20) (20)
Significant unobservable inputs (Level 3) | Issued debt    
Disclosure of detailed information about financial instruments [line items]    
Financial liabilities designated at fair value (2,397) (3,760)
Total liabilities (2,397) (3,760)
Significant unobservable inputs (Level 3) | Reverse repurchase and repurchase agreements    
Disclosure of detailed information about financial instruments [line items]    
Financial assets at fair value through the income statement   97
Total assets   97
Financial liabilities designated at fair value   (887)
Total liabilities   (887)
Significant unobservable inputs (Level 3) | Other products    
Disclosure of detailed information about financial instruments [line items]    
Trading portfolio assets 737 444
Financial assets at fair value through the income statement 94 104
Derivative financial assets 745 431
Investment property 42 43
Total assets 1,618 1,022
Trading portfolio liabilities (29) (17)
Financial liabilities designated at fair value (81) (207)
Derivative financial instruments (995) (851)
Total liabilities (1,105) (1,075)
Significant unobservable inputs (Level 3) | Interest rate derivatives    
Disclosure of detailed information about financial instruments [line items]    
Derivative financial assets 942 759
Total assets 942 759
Derivative financial instruments (1,436) (612)
Total liabilities (1,436) (612)
Significant unobservable inputs (Level 3) | Equity risk    
Disclosure of detailed information about financial instruments [line items]    
Derivative financial assets 289 522
Total assets 289 522
Derivative financial instruments (424) (1,602)
Total liabilities £ (424) £ (1,602)