v3.26.1
Financial instruments - valuation - Movement in Level 3 portfolios - Assets (Details) - GBP (£)
£ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Movement in level 3 assets    
Transfers into level 3 of fair value hierarchy through changed observability of swaps and increase in the proportion of trades with unobservable inputs in structured netting, assets and liabilities £ 61  
Transfers out of Level 3 of fair value hierarchy through decrease in observability of inputs, assets and liabilities 51  
At fair value    
Movement in level 3 assets    
Financial assets at beginning of period 150,538  
Financial assets at end of period 161,987  
At fair value | Level 3    
Movement in level 3 assets    
Financial assets at beginning of period 1,253 £ 1,682
Amounts recorded in the income statement (16) (64)
Amount recorded in the statement of comprehensive income 2 11
Level 3 transfers in 86 40
Level 3 transfers out (91) (22)
Purchases/Originations 532 218
Settlements/Other decreases (11) (33)
Sales (114) (253)
Foreign exchange and other adjustments   4
Financial assets at end of period 1,641 1,583
Amounts recorded in the income statement in respect of balances held at period end - unrealised 82 55
At fair value | Level 3 | Derivatives    
Movement in level 3 assets    
Financial assets at beginning of period 472 630
Amounts recorded in the income statement (30) (65)
Level 3 transfers in 41 40
Level 3 transfers out (50) (6)
Purchases/Originations 39 70
Settlements/Other decreases   (2)
Sales (33) (31)
Foreign exchange and other adjustments   1
Financial assets at end of period 439 637
Amounts recorded in the income statement in respect of balances held at period end - unrealised 66 57
At fair value | Level 3 | Other trading assets    
Movement in level 3 assets    
Financial assets at beginning of period 96 278
Amounts recorded in the income statement 13 2
Purchases/Originations 157 89
Settlements/Other decreases (10) (31)
Sales   (97)
Foreign exchange and other adjustments   2
Financial assets at end of period 256 243
Amounts recorded in the income statement in respect of balances held at period end - unrealised 13 1
At fair value | Level 3 | Other financial assets    
Movement in level 3 assets    
Financial assets at beginning of period 685 774
Amounts recorded in the income statement 1 (1)
Amount recorded in the statement of comprehensive income 2 11
Level 3 transfers in 45  
Level 3 transfers out (41) (16)
Purchases/Originations 336 59
Settlements/Other decreases (1)  
Sales (81) (125)
Foreign exchange and other adjustments   1
Financial assets at end of period 946 703
Amounts recorded in the income statement in respect of balances held at period end - unrealised £ 3 £ (3)