Defined Benefit Postretirement Plans and Defined Contribution Plan - Obligations and Funded Status (Details) - U.S. - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Accumulated benefit obligation	$ 260	$ 298
Change in benefit obligations:
Beginning balance	308	354
Service cost	16	19	$ 19
Interest cost	7	9	12
Actuarial (gain) loss	(15)	36
Gain due to curtailment	0	(1)
Settlements paid	(43)	(104)
Benefits paid	(4)	(5)
Ending balance	269	308	354
Change in fair value of plan assets:
Beginning balance	194	236
Actual return on plan assets	13	18
Employer contributions	32	49
Settlements paid	(43)	(104)
Benefits paid	(4)	(5)
Ending balance	192	194	236
Funded status of plans at December 31
Funded status of plans at December 31	(77)	(114)
Amounts recognized in the consolidated balance sheets:
Current liabilities	(3)	(4)
Noncurrent liabilities	(74)	(110)
Accrued benefit cost	(77)	(114)
Pretax amounts in accumulated other comprehensive loss:
Net loss	37	72
Prior service credit	(13)	(19)
Other Benefits
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Accumulated benefit obligation	73	80
Change in benefit obligations:
Beginning balance	80	89
Service cost	0	1
Interest cost	2	2
Actuarial (gain) loss	1	4
Gain due to curtailment	0	0
Settlements paid	0	0
Benefits paid	(10)	(16)
Ending balance	73	80	89
Change in fair value of plan assets:
Beginning balance	0	0
Actual return on plan assets	0	0
Employer contributions	10	16
Settlements paid	0	0
Benefits paid	(10)	(16)
Ending balance	0	0	$ 0
Funded status of plans at December 31
Funded status of plans at December 31	(73)	(80)
Amounts recognized in the consolidated balance sheets:
Current liabilities	(10)	(10)
Noncurrent liabilities	(63)	(70)
Accrued benefit cost	(73)	(80)
Pretax amounts in accumulated other comprehensive loss:
Net loss	23	24
Prior service credit	$ (81)	$ (97)