v3.25.4
Tax - Narrative (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Taxation at UK corporation tax rate of 25.0% (2024: 25.0%, 2023: 23.5%) 25.00% 25.00% 23.50%
Average effective tax rate 22.70% 22.60% 19.10%
– dilution loss on the Group’s investment in BoCom 0.40% 0.00% 0.00%
– movements in unrecognised deferred tax 1.00% 0.70% (0.10%)
– fines and provisions for legal settlements 1.00% 0.00% 0.00%
– adjustments in respect of prior periods (0.30%) (0.10%) 0.10%
– impact of business disposals 0.30% 0.00% 0.00%
– non-taxable income and gains 0.00% 3.60% 0.00%
Tax rate effect of gain (loss) on pillar two global minimum tax charge   0.70%  
Exposures to legacy tax cases $ 118    
Management's approved financial forecast period 5 years    
Deferred tax liability (asset) $ (5,135) $ (5,524) $ (6,516)
Gross temporary differences, unused tax losses and unused tax credits for which no deferred tax asset is recognised 13,800 11,000  
Unused tax losses for which no deferred tax asset recognised $ 3,400 3,500  
Deferred tax asset, expiration period, with expiry date 10 years    
Deferred tax asset, expiration period, without expiry date 10 years    
Temporary differences related to unrecognised deferred tax liabilities arising on investments in subsidiaries and branches $ 15,900 15,200  
Deferred tax liabilities $ 2,100 $ 1,317  
Argentina business      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
– impact of business disposals   4.80%  
France      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
– movements in unrecognised deferred tax 1.00%    
Bank Of Communications Co., Limited      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
– dilution loss on the Group’s investment in BoCom 1.20%    
Pro Forma      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Average effective tax rate 21.20% 21.40%  
Expiration within 10 years      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Gross temporary differences, unused tax losses and unused tax credits for which no deferred tax asset is recognised $ 1,300 $ 1,000  
Not subject to expiration      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Gross temporary differences, unused tax losses and unused tax credits for which no deferred tax asset is recognised $ 7,600 6,000  
UK      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Taxation at UK corporation tax rate of 25.0% (2024: 25.0%, 2023: 23.5%) 25.00%    
Deferred tax liability (asset) $ (1,500) (2,600)  
Deferred tax asset and liability expiration period 2 years    
United States      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Taxation at UK corporation tax rate of 25.0% (2024: 25.0%, 2023: 23.5%) 21.00%    
Deferred tax liability (asset) $ (2,800) (3,000)  
Period for substantial recovery of deferred tax assets (liabilities) 13 years    
Gross temporary differences, unused tax losses and unused tax credits for which no deferred tax asset is recognised $ 3,800 3,800  
United States | 10 to 15 years      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax liability (asset) (700)    
France      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax liability (asset) $ (800) (500)  
Period for majority recovery of deferred tax assets (liabilities) 5 years    
Gross temporary differences, unused tax losses and unused tax credits for which no deferred tax asset is recognised $ 1,400 $ 700  
Unused tax losses for which no deferred tax asset recognised $ 300    
Hong Kong      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Taxation at UK corporation tax rate of 25.0% (2024: 25.0%, 2023: 23.5%) 16.50% 16.50% 16.50%
Unused tax losses | United States      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax liability (asset) $ (1,000)    
Unused tax losses | France      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax liability (asset) (800)    
Unused tax losses | France | Within 12 years      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax liability (asset) $ (700)    
Unused tax losses | Minimum | United States      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax asset and liability expiration period 9 years    
Unused tax losses | Minimum | France      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax asset and liability expiration period 10 years    
Unused tax losses | Maximum | United States      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax asset and liability expiration period 12 years    
Pension | UK      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax liability (asset) $ 2,000    
Temporary differences from investments in subsidiaries and branches      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Deferred tax liabilities $ 800 $ 700