Accumulated Other Comprehensive Loss - Changes in Accumulated Other Comprehensive Loss by Component, After Tax and Minority Interest (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 3,259	$ 4,545		$ 5,070
Ending balance	5,184	3,259		4,545
Foreign Currency Translation Adjustment
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(1,284)	(1,156)		(1,160)
Other comprehensive income (loss) before reclassifications	(118)	(128)	[1]	4	[1]
Amounts reclassified from accumulated other comprehensive loss	0	0		0
Ending balance	(1,402)	(1,284)		(1,156)
Unrecognized Net Actuarial Losses and Prior Service Costs
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(2,856)	(2,983)		(2,923)
Other comprehensive income (loss) before reclassifications	153	(4)	[1]	(168)	[1]
Amounts reclassified from accumulated other comprehensive loss	138	131		108
Ending balance	(2,565)	(2,856)		(2,983)
Deferred Derivative Gains (Losses)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	5	3		7
Other comprehensive income (loss) before reclassifications	1	15	[1]	10	[1]
Amounts reclassified from accumulated other comprehensive loss	(2)	(13)		(14)
Ending balance	4	5		3
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(4,135)	(4,136)		(4,076)
Other comprehensive income (loss) before reclassifications	36	(117)	[1]	(154)	[1]
Amounts reclassified from accumulated other comprehensive loss	136	118		94
Ending balance	$ (3,963)	$ (4,135)		$ (4,136)

[1] Includes adjustments to AOCL of $27 million and $(32) million in 2020 and 2019, respectively, to adjust the respective prior year obligation of our frozen U.K. pension plan.