Accumulated Other Comprehensive Loss - Changes in Accumulated Other Comprehensive Loss by Component (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 634	$ 756
Balance	679	764
Pension and OPEB liability adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(17)	(19)
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from AOCL	(3)	(2)
Income tax benefit (expense)	1	0
Net current period other comprehensive (loss) income	(2)	(2)
Balance	(19)	(21)
Interest rate swaps
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(24)	(46)
Other comprehensive income (loss) before reclassifications	22	10
Amounts reclassified from AOCL	3	4
Income tax benefit (expense)	(6)	(3)
Net current period other comprehensive (loss) income	19	11
Balance	(5)	(35)
Foreign currency items
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(32)	(24)
Other comprehensive income (loss) before reclassifications	(0)	(6)
Amounts reclassified from AOCL	0	0
Income tax benefit (expense)	0	0
Net current period other comprehensive (loss) income	(0)	(6)
Balance	(32)	(30)
Accumulated Other Comprehensive (Loss) Income, net of tax
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(73)	(89)
Other comprehensive income (loss) before reclassifications	22	4
Amounts reclassified from AOCL	0	2
Income tax benefit (expense)	(5)	(3)
Net current period other comprehensive (loss) income	17	3
Balance	$ (56)	$ (86)