v3.26.1
Fair value of financial instruments - Unrealised gains and losses recognised in the period on Level 3 assets and liabilities held at period end (Details) - GBP (£)
£ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Disclosure of detailed information about financial instruments [line items]    
Trading income £ 4,617 £ 4,358
Other income [1] 252 29
Other comprehensive income 138 151
Significant unobservable inputs (Level 3)    
Disclosure of detailed information about financial instruments [line items]    
Trading income 160 192
Other income 25 9
Other comprehensive income 0 0
Total 185 201
Significant unobservable inputs (Level 3) | Investment property    
Disclosure of detailed information about financial instruments [line items]    
Trading income 0 0
Other income 0 0
Other comprehensive income 0 0
Total 0 0
Significant unobservable inputs (Level 3) | Net derivative financial instruments    
Disclosure of detailed information about financial instruments [line items]    
Trading income 104 165
Other income (1) 1
Other comprehensive income 0 0
Total 103 166
Trading portfolio liabilities | Significant unobservable inputs (Level 3)    
Disclosure of detailed information about financial instruments [line items]    
Trading income 12 34
Other income 0 0
Other comprehensive income 0 0
Total 12 34
Financial liabilities designated at fair value | Significant unobservable inputs (Level 3)    
Disclosure of detailed information about financial instruments [line items]    
Trading income 70 86
Other income 0 0
Other comprehensive income 0 0
Total 70 86
Trading portfolio assets | Significant unobservable inputs (Level 3)    
Disclosure of detailed information about financial instruments [line items]    
Trading income 26 21
Other income 0 0
Other comprehensive income 0 0
Total 26 21
Financial assets at fair value through the income statement | Significant unobservable inputs (Level 3)    
Disclosure of detailed information about financial instruments [line items]    
Trading income (52) (117)
Other income 26 (20)
Other comprehensive income 0 0
Total (26) (137)
Financial assets at fair value through other comprehensive income | Significant unobservable inputs (Level 3)    
Disclosure of detailed information about financial instruments [line items]    
Trading income 0 3
Other income 0 28
Other comprehensive income 0 0
Total £ 0 £ 31
[1] Other income includes c.£225m gain recognised on sale of the AA portfolio on 24 April 2026.