v3.25.4
Retirement benefits - Breakdown of the UKRF benefit obligation (Details) - GBP (£)
£ in Millions
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) £ (3,083) £ (3,099)  
Retirement benefit obligations      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 18,475 19,524 £ 21,420
UK | Retirement benefit obligations | Barclays Bank Section      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 17,674    
UK | Retirement benefit obligations | UKRF      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset)   18,729  
UK | Retirement benefit obligations | Active members | Barclays Bank Section      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 981    
UK | Retirement benefit obligations | Active members | UKRF      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset)   1,699  
UK | Retirement benefit obligations | Deferred members (Afterwork) | Barclays Bank Section      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 1,828    
UK | Retirement benefit obligations | Deferred members (Afterwork) | UKRF      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset)   1,716  
UK | Retirement benefit obligations | Deferred members (Non-Afterwork) | Barclays Bank Section      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 3,786    
UK | Retirement benefit obligations | Deferred members (Non-Afterwork) | UKRF      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset)   4,269  
UK | Retirement benefit obligations | Pensioners and Dependents | Barclays Bank Section      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) £ 11,079    
UK | Retirement benefit obligations | Pensioners and Dependents | UKRF      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset)   £ 11,045