v3.25.4
Related party transactions and Directors' remuneration - Disclosure of amounts included in the Group's financial statements by category (Details) - GBP (£)
£ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Disclosure of transactions between related parties [line items]      
Operating Income £ 20,927 £ 19,037 £ 18,268
Operating expenses (13,105) (12,673) (12,463)
Total assets 1,245,473 1,218,524 1,185,200
Total liabilities 1,183,160 1,159,304 1,124,700
Parent      
Disclosure of transactions between related parties [line items]      
Operating Income (2,276) (1,994) (1,712)
Operating expenses (105) (92) (89)
Total assets 1,136 1,338  
Total liabilities 46,360 44,678  
Fellow subsidiaries      
Disclosure of transactions between related parties [line items]      
Operating Income 75 172 164
Operating expenses (4,794) (4,361) (4,157)
Total assets 8,497 6,753  
Total liabilities 8,438 8,588  
Pension funds      
Disclosure of transactions between related parties [line items]      
Operating Income 4 (1) 1
Operating expenses 0 0 (1)
Total assets 0 0  
Total liabilities 140 176  
Other related parties      
Disclosure of transactions between related parties [line items]      
Operating Income 42 54 52
Operating expenses 0 0 £ 0
Total assets 0 1,104  
Total liabilities £ 126 £ 64