v3.25.2
Retirement benefits - Summary of Remeasurements (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Actuarial (losses)/gains on obligations:      
Total $ (2,375) $ 27,943 $ 2,001
Return on plan assets in excess/(shortage) of interest income 1,243 (20,612) 8,185
Other movements 44 (349) 5
Total remeasurements (1,088) 6,982 10,191
Pensions      
Actuarial (losses)/gains on obligations:      
Due to changes in financial assumptions (1,513) 28,840 1,915
Due to experience adjustments (491) (2,956) 136
Due to changes in demographic assumptions (299) 27 (320)
OPEB      
Actuarial (losses)/gains on obligations:      
Due to changes in financial assumptions (264) 527 59
Due to experience adjustments 230 1,480 322
Due to changes in demographic assumptions (38) $ 25 $ (111)
Adjustments for prescription drug rebates $ 782