v3.25.4
Tax - Disclosure of deferred tax assets and liabilities (Details) - GBP (£)
£ in Millions
Dec. 31, 2025
Dec. 31, 2024
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Deferred tax assets £ 2,936 £ 4,133
Deferred tax liability (1) (2)
Net deferred tax 2,935 4,131
UK Tax Group    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Deferred tax assets 1,712 2,638
Deferred tax liability (1) (2)
UK Tax Group | UK    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Deferred tax assets 1,433 2,315
US Intermediate Holding Company Tax Group ("IHC Tax Group")    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Deferred tax assets 1,005 1,162
Barclays Bank PLC's US Branch Tax Group    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Deferred tax assets 255 270
Other (outside the UK and US tax groups)    
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]    
Deferred tax assets £ 243 £ 386