Stockholders' Equity - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			$ 1,916
Balance at end of period	$ 1,844		1,844
Other comprehensive income (loss) attributable to noncontrolling interests	(1)	$ (7)	5	$ 1
Foreign currency translation adjustments and other
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(366)	(244)	(395)	(263)
Other comprehensive income (loss) before reclassifications adjustments	(16)	(94)	11	(75)
Other comprehensive income (loss) before reclassifications adjustments	0	0	0	0
Other comprehensive income (loss)	(16)	(94)	11	(75)
Income tax provision (benefit)	(1)	2	1	2
Balance at end of period	(383)	(336)	(383)	(336)
Pensions and other postretirement benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(296)	(272)	(297)	(275)
Other comprehensive income (loss) before reclassifications adjustments	0	0	0	0
Other comprehensive income (loss) before reclassifications adjustments	2	5	3	9
Other comprehensive income (loss)	2	5	3	9
Income tax provision (benefit)	(4)	(1)	(4)	(2)
Balance at end of period	(298)	(268)	(298)	(268)
Cash flow hedge instruments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	4	0	0	0
Other comprehensive income (loss) before reclassifications adjustments	(3)	0	1	0
Other comprehensive income (loss) before reclassifications adjustments	0	0	0	0
Other comprehensive income (loss)	(3)	0	1	0
Income tax provision (benefit)	0	0	0	0
Balance at end of period	$ 1	$ 0	$ 1	$ 0