v3.25.2
Legal, competition and regulatory matters (Details)
£ in Millions, $ in Millions
 1 Months Ended 6 Months Ended 12 Months Ended
Oct. 31, 2024
request
Jan. 31, 2024
decision
Nov. 30, 2023
request
Apr. 30, 2021
USD ($)
Jun. 30, 2025
lawsuit
plaintiff
Dec. 31, 2018
GBP (£)
Dec. 31, 2008
USD ($)
Civil actions in respect of USD LIBOR              
Disclosure of contingent liabilities [line items]              
Number of lawsuits with specified damages sought         1    
US residential and commercial mortgage-related activity and litigation | Originated and sold to third parties by acquired subsidiary | RMBS repurchase requests              
Disclosure of contingent liabilities [line items]              
Number of lawsuits with specified damages sought         1    
Civil actions in respect of VRDO - SNDY              
Disclosure of contingent liabilities [line items]              
Number of lawsuits with specified damages sought         3    
Interest rate swap and credit default swap US Civil Actions              
Disclosure of contingent liabilities [line items]              
Number of lawsuits with specified damages sought         1    
Civil actions in respect of the US Anti-Terrorism Act              
Disclosure of contingent liabilities [line items]              
Number of lawsuits with specified damages sought         8    
Number of plaintiffs | plaintiff         4,000    
Civil actions in respect of the US Anti-Terrorism Act - EDNY              
Disclosure of contingent liabilities [line items]              
Number of lawsuits with specified damages sought         6    
Number of lawsuits dismissed         3    
Number of lawsuits subject to appeal         1    
Number of lawsuits consolidated into a separate lawsuit         2    
Number of separate lawsuits         1    
Number of initial lawsuits amended         1    
Number of lawsuits stayed         2    
Civil actions in respect of the US Anti-Terrorism Act - SDNY              
Disclosure of contingent liabilities [line items]              
Number of lawsuits with specified damages sought         2    
Motor Finance Commission Arrangements              
Disclosure of contingent liabilities [line items]              
Number of final decisions by the UK Financial Ombudsman Service | decision   2          
Number of final decisions by the UK Financial Ombudsman Service about commision arrangements | decision   1          
Number of judgment issued in motor finance commission cases | request 3            
HMRC assessments concerning UK VAT              
Disclosure of contingent liabilities [line items]              
Loss contingency, damages sought, claimed amounts, value | £           £ 181  
HMRC assessments concerning UK VAT | Barclays UK              
Disclosure of contingent liabilities [line items]              
Loss contingency, damages sought, claimed amounts, value | £           128  
Barclays Bank PLC | Other proceedings              
Disclosure of contingent liabilities [line items]              
Number of arbitration requests received | request     2        
Barclays Bank PLC | BDC Finance LLC              
Disclosure of contingent liabilities [line items]              
Litigation settlements approved, value | $       $ 3.3     $ 298.0
Barclays Bank PLC | HMRC assessments concerning UK VAT              
Disclosure of contingent liabilities [line items]              
Loss contingency, damages sought, claimed amounts, value | £           £ 53