v3.25.4
Retirement benefits - Summary of Retirement Benefits by Financial Position (Details) - USD ($)
$ 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) $ (2,084) $ 3,251  
Non-current assets 5,052 10,003  
Non-current liabilities: (7,136) (6,752)  
Pensions      
Disclosure of net defined benefit liability (asset) [line items]      
Non-current liabilities: (4,152) (3,874)  
OPEB      
Disclosure of net defined benefit liability (asset) [line items]      
Non-current liabilities: (2,984) (2,878)  
Obligations      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) (67,718) (66,054) $ (78,024)
Obligations | OPEB      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) (2,985) (2,878) (3,101)
Plan assets      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 72,913 69,707 $ 79,961
Asset ceilings      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) $ (7,279) $ (402)