Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
AOCI, Translation adjustments, net of tax	$ (35)						$ (35)		$ (31)
AOCI, Post-retirement benefits and other, net of tax	(48)						(48)		(49)
Accumulated other comprehensive loss, net of tax	(83)						(83)		$ (80)
Other comprehensive (loss) income, translation adjustments, before reclassification adjustment, net of tax							(4)
Other comprehensive (loss) income, post-retirement benefits, before reclassification adjustment, net of tax							1
Accumulated other comprehensive loss, before reclassification adjustment, net of tax							(3)
Other comprehensive (loss) income, translation adjustments, net of tax	(5)			$ 1			(4)
Other comprehensive (loss) income, post-retirement benefits, net of tax				1			1	$ 1
Accumulated Other Comprehensive Loss, net of tax	$ (5)	$ 3	$ (1)	$ 2	$ 2	$ (3)	$ (3)	$ 1