v3.22.0.1
Post-Employment Benefits - Expense (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Defined Benefit Plans      
Defined benefit plan net periodic benefit cost      
Service cost - benefits earned during the year $ 391 $ 336 $ 250
Interest cost on projected benefit obligations 248 300 337
Expected return on plans' assets (843) (770) (710)
Amortization of actuarial losses 317 255 132
Amortization of prior service cost (credits) 1 1 1
Total net cost 114 122 10
Net actuarial (gains) losses, net of any prior service credits (1,141) 611 944
Medical and Dental Plans      
Defined benefit plan net periodic benefit cost      
Service cost - benefits earned during the year 56 46 23
Interest cost on projected benefit obligations 33 42 52
Expected return on plans' assets (27) (28) (27)
Amortization of actuarial losses 29 21 22
Amortization of prior service cost (credits) (28) (28) (32)
Total net cost 63 53 38
Net actuarial (gains) losses, net of any prior service credits $ (45) $ (23) $ 190