v3.26.1
Fair values of financial assets and liabilities - Schedule of Financial Liabilities Carried at Fair Value by Valuation Hierarchy (Details) - GBP (£)
£ in Millions
Jun. 30, 2026
Dec. 31, 2025
Disclosure of fair value measurement of liabilities [line items]    
Debt securities in issue £ 95,091 £ 82,514
Financial liabilities at fair value through profit or loss 31,310 27,909
Derivative financial instruments 17,562 15,842
Liabilities arising from non-participating investment contracts 66,639 61,640
Total financial liabilities carried at fair value 115,775 105,681
Derivative financial liabilities 17,826 16,132
Financial liabilities at fair value through profit or loss    
Disclosure of fair value measurement of liabilities [line items]    
Debt securities in issue 4,238 4,243
Liabilities in respect of securities sold under repurchase agreements    
Disclosure of fair value measurement of liabilities [line items]    
Financial liabilities at fair value through profit or loss that meet definition of held for trading 24,682 21,710
Short positions in securities    
Disclosure of fair value measurement of liabilities [line items]    
Financial liabilities at fair value through profit or loss that meet definition of held for trading 2,336 1,956
Other    
Disclosure of fair value measurement of liabilities [line items]    
Other 54 0
Liabilities arising from non-participating investment contracts    
Disclosure of fair value measurement of liabilities [line items]    
Liabilities arising from non-participating investment contracts 66,639 61,640
Level 1    
Disclosure of fair value measurement of liabilities [line items]    
Debt securities in issue 0 0
Financial liabilities at fair value through profit or loss 2,317 1,722
Derivative financial instruments 145 29
Total financial liabilities carried at fair value 2,462 1,751
Level 1 | Liabilities in respect of securities sold under repurchase agreements    
Disclosure of fair value measurement of liabilities [line items]    
Financial liabilities at fair value through profit or loss that meet definition of held for trading 0 0
Level 1 | Short positions in securities    
Disclosure of fair value measurement of liabilities [line items]    
Financial liabilities at fair value through profit or loss that meet definition of held for trading 2,317 1,722
Level 1 | Other    
Disclosure of fair value measurement of liabilities [line items]    
Other 0 0
Level 1 | Liabilities arising from non-participating investment contracts    
Disclosure of fair value measurement of liabilities [line items]    
Liabilities arising from non-participating investment contracts 0 0
Level 2    
Disclosure of fair value measurement of liabilities [line items]    
Debt securities in issue 4,221 4,226
Financial liabilities at fair value through profit or loss 28,976 26,170
Derivative financial instruments 17,477 15,879
Total financial liabilities carried at fair value 113,092 103,689
Level 2 | Liabilities in respect of securities sold under repurchase agreements    
Disclosure of fair value measurement of liabilities [line items]    
Financial liabilities at fair value through profit or loss that meet definition of held for trading 24,682 21,710
Level 2 | Short positions in securities    
Disclosure of fair value measurement of liabilities [line items]    
Financial liabilities at fair value through profit or loss that meet definition of held for trading 19 234
Level 2 | Other    
Disclosure of fair value measurement of liabilities [line items]    
Other 54 0
Level 2 | Liabilities arising from non-participating investment contracts    
Disclosure of fair value measurement of liabilities [line items]    
Liabilities arising from non-participating investment contracts 66,639 61,640
Level 3    
Disclosure of fair value measurement of liabilities [line items]    
Debt securities in issue 17 17
Financial liabilities at fair value through profit or loss 17 17
Derivative financial instruments 204 224
Total financial liabilities carried at fair value 221 241
Level 3 | Liabilities in respect of securities sold under repurchase agreements    
Disclosure of fair value measurement of liabilities [line items]    
Financial liabilities at fair value through profit or loss that meet definition of held for trading 0 0
Level 3 | Short positions in securities    
Disclosure of fair value measurement of liabilities [line items]    
Financial liabilities at fair value through profit or loss that meet definition of held for trading 0 0
Level 3 | Other    
Disclosure of fair value measurement of liabilities [line items]    
Other 0 0
Level 3 | Liabilities arising from non-participating investment contracts    
Disclosure of fair value measurement of liabilities [line items]    
Liabilities arising from non-participating investment contracts £ 0 £ 0