v3.26.1
Net fee and commission income (Details) - GBP (£)
£ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers £ 5,844 £ 5,577
Other non-contract fee income 101 79
Fee and commission income 5,945 5,656
Fee and commission expense (1,986) (1,972)
Net fee and commission income 3,959 3,684
Transactional    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 2,338 2,496
Advisory    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 626 448
Brokerage and execution    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 1,281 1,158
Underwriting and syndication    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 1,589 1,460
Other    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 10 15
Operating segments | Barclays UK    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 725 732
Other non-contract fee income 0 0
Fee and commission income 725 732
Fee and commission expense (241) (242)
Net fee and commission income 484 490
Operating segments | Barclays UK | Transactional    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 610 608
Operating segments | Barclays UK | Advisory    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 0 0
Operating segments | Barclays UK | Brokerage and execution    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 95 100
Operating segments | Barclays UK | Underwriting and syndication    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 18 18
Operating segments | Barclays UK | Other    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 2 6
Operating segments | Barclays UK Corporate Bank    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 287 280
Other non-contract fee income 14 14
Fee and commission income 301 294
Fee and commission expense (43) (46)
Net fee and commission income 258 248
Operating segments | Barclays UK Corporate Bank | Transactional    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 229 229
Operating segments | Barclays UK Corporate Bank | Advisory    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 0 0
Operating segments | Barclays UK Corporate Bank | Brokerage and execution    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 0 0
Operating segments | Barclays UK Corporate Bank | Underwriting and syndication    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 58 51
Operating segments | Barclays UK Corporate Bank | Other    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 0 0
Operating segments | Barclays Private Bank and Wealth Management    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 279 260
Other non-contract fee income 0 0
Fee and commission income 279 260
Fee and commission expense (21) (18)
Net fee and commission income 258 242
Operating segments | Barclays Private Bank and Wealth Management | Transactional    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 14 15
Operating segments | Barclays Private Bank and Wealth Management | Advisory    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 174 166
Operating segments | Barclays Private Bank and Wealth Management | Brokerage and execution    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 91 79
Operating segments | Barclays Private Bank and Wealth Management | Underwriting and syndication    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 0 0
Operating segments | Barclays Private Bank and Wealth Management | Other    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 0 0
Operating segments | Barclays Investment Bank    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 3,163 2,823
Other non-contract fee income 87 65
Fee and commission income 3,250 2,888
Fee and commission expense (734) (675)
Net fee and commission income 2,516 2,213
Operating segments | Barclays Investment Bank | Transactional    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 165 171
Operating segments | Barclays Investment Bank | Advisory    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 452 282
Operating segments | Barclays Investment Bank | Brokerage and execution    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 1,095 979
Operating segments | Barclays Investment Bank | Underwriting and syndication    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 1,451 1,391
Operating segments | Barclays Investment Bank | Other    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 0 0
Operating segments | Barclays US Consumer Bank    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 1,267 1,333
Other non-contract fee income 0 0
Fee and commission income 1,267 1,333
Fee and commission expense (921) (959)
Net fee and commission income 346 374
Operating segments | Barclays US Consumer Bank | Transactional    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 1,205 1,333
Operating segments | Barclays US Consumer Bank | Advisory    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 0 0
Operating segments | Barclays US Consumer Bank | Brokerage and execution    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 0 0
Operating segments | Barclays US Consumer Bank | Underwriting and syndication    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 62 0
Operating segments | Barclays US Consumer Bank | Other    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 0 0
Head Office    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 123 149
Other non-contract fee income 0 0
Fee and commission income 123 149
Fee and commission expense (26) (32)
Net fee and commission income 97 117
Head Office | Transactional    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 115 140
Head Office | Advisory    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 0 0
Head Office | Brokerage and execution    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 0 0
Head Office | Underwriting and syndication    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers 0 0
Head Office | Other    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Total revenue from contracts with customers £ 8 £ 9