v3.25.2
Retirement benefits - Summary of Retirement Benefits by Financial Position (Details) - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) $ 3,251 $ 1,602  
Non-current assets 10,003 9,151  
Non-current liabilities: (6,752) (7,549)  
Pensions      
Disclosure of net defined benefit liability (asset) [line items]      
Non-current liabilities: (3,874) (4,448)  
OPEB      
Disclosure of net defined benefit liability (asset) [line items]      
Non-current liabilities: (2,878) (3,101)  
Obligations      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) (66,054) (78,024) $ (73,481)
Obligations | OPEB      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) (2,878) (3,101) (2,879)
Plan assets      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) 69,707 79,961 $ 76,756
Asset ceilings      
Disclosure of net defined benefit liability (asset) [line items]      
Net defined benefit liability (asset) $ (402) $ (335)