Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 196	$ 88	$ 510
Derivatives qualifying as cash flow hedges:
Gain (loss) on derivatives qualifying as cash flow hedges, net of tax (benefit) of $1, ($10), and $2, respectively	6	(14)	1
Less: Reclassification adjustment for loss on derivatives included in net income, net of tax (benefit) of $0, ($3), and ($4), respectively	(2)	(3)	(6)
Net derivatives qualifying as cash flow hedges	8	(11)	7
Pension and postretirement benefits:
Changes in pension and postretirement benefits, net of tax (benefit) of $9, ($27), and ($19), respectively	28	(65)	(34)
Less: Amortization of prior service cost included in net periodic benefit cost, net of tax (benefit) of ($2), ($10), and ($7), respectively	(6)	(14)	(9)
Net pension and postretirement benefits	34	(51)	(25)
Foreign currency translation:
Changes in foreign currency translation, net of tax of $0 in all periods	(40)	58	(53)
Less: Translation loss realized upon sale of foreign equity method investment, net of tax (benefit) of ($2), $0, and $0, respectively	(4)	0	0
Net foreign currency translation	(36)	58	(53)
Other comprehensive income (loss), net of tax	6	(4)	(71)
Comprehensive income	$ 202	$ 84	$ 439