Pensions Benefit Plans and Other Postretirement Benefits - Projected and Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets (Details) - Pension Benefit Plans - Funded Plan - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
U.S.
Projected Benefit Obligation Exceeds the Fair Value of Plan Assets
Projected benefit obligations	$ 1,590	$ 1,505
Accumulated benefit obligation	1,590	1,505
Fair value of plan assets	1,324	1,215
Accumulated Benefit Obligations Exceeds the Fair Value of Plan Assets
Projected benefit obligations	1,590	1,505
Accumulated benefit obligation	1,590	1,505
Fair value of plan assets	1,324	1,215
Non-U.S.
Projected Benefit Obligation Exceeds the Fair Value of Plan Assets
Projected benefit obligations	331	952
Accumulated benefit obligation	309	927
Fair value of plan assets	67	706
Accumulated Benefit Obligations Exceeds the Fair Value of Plan Assets
Projected benefit obligations	331	952
Accumulated benefit obligation	309	927
Fair value of plan assets	$ 67	$ 706