v3.26.1
Retirement benefit obligations - Schedule of Defined Benefit Scheme Obligations (Details) - GBP (£)
£ in Millions
Jun. 30, 2026
Dec. 31, 2025
Schedule of Retirement Benefits Recognised in Balance Sheet [Line Items]    
Total amounts recognised in the balance sheet £ 2,744 £ 2,575
Retirement benefit assets 2,860 2,695
Retirement benefit obligations (116) (120)
Defined benefit pension schemes:    
Schedule of Retirement Benefits Recognised in Balance Sheet [Line Items]    
Total amounts recognised in the balance sheet 2,779 2,612
Other post-retirement schemes    
Schedule of Retirement Benefits Recognised in Balance Sheet [Line Items]    
Total amounts recognised in the balance sheet (35) (37)
Present value of funded obligations    
Schedule of Retirement Benefits Recognised in Balance Sheet [Line Items]    
Total amounts recognised in the balance sheet (25,483) (26,571)
Fair value of scheme assets    
Schedule of Retirement Benefits Recognised in Balance Sheet [Line Items]    
Total amounts recognised in the balance sheet £ 28,262 £ 29,183