v3.21.1
Post-Employment Benefits (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Defined benefit plans    
Defined benefit and other post-employment plans    
Service cost $ 112 $ 92
Interest cost 58 61
Expected return on plan assets (166) (135)
Amortization of prior service cost (credit) 1 1
Amortization of actuarial loss 70 54
Net periodic benefit cost 75 73
Other post-employment plans    
Defined benefit and other post-employment plans    
Service cost 12 12
Interest cost 5 9
Expected return on plan assets 0 0
Amortization of prior service cost (credit) (10) (1)
Amortization of actuarial loss 8 7
Net periodic benefit cost $ 15 $ 27