Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 254	$ 401	$ 549
Other comprehensive loss, before tax:
Foreign currency translation adjustment	(23)	28	(85)
Net change in derivative hedge agreements:
Unrealized gain (loss)	9	(14)	(8)
Amount of (gain) loss reclassified into net income	(3)	12	4
Net change in post-retirement benefit plans:
Net loss	(78)	(83)	(37)
Prior service credit	5	0	0
Amortization of prior service credit cost	(3)	(4)	(4)
Amortization of net actuarial loss into net income	19	12	13
Settlement	0	9	1
Foreign currency translation adjustment	(19)	(3)	15
Other comprehensive loss, before tax	(93)	(43)	(101)
Income tax (benefit) expense related to other comprehensive loss	(54)	(5)	10
Other comprehensive loss, net of tax	(39)	(38)	(111)
Comprehensive income	215	363	438
Less: comprehensive (loss) gain attributable to noncontrolling interests	(1)	1	(2)
Comprehensive income	$ 216	$ 362	$ 440