Pension and Other Postretirement Benefit Plans - Change in Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets as of beginning of year	$ 3,806
Fair value of plan assets as of end of year	3,856	$ 3,806
Pension Plans
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets as of beginning of year	3,806	3,862
Actual return on plan assets	296	241
Employer contributions	86	91
Participant contributions	6	7
Settlements	(15)	(118)
Benefits paid	(345)	(341)
Effect of foreign currency exchange rate changes	22	64
Fair value of plan assets as of end of year	3,856	3,806
Funded status as of end of year	(1,041)	(1,440)
OPEB Plans
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets as of beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	11	11
Participant contributions	2	2
Settlements	0	0
Benefits paid	(13)	(13)
Effect of foreign currency exchange rate changes	0	0
Fair value of plan assets as of end of year	0	0
Funded status as of end of year	$ (122)	$ (136)