Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			$ 2,731
Total other comprehensive (loss) income	$ (10)	$ 8	(12)	$ 17
Balance at end of period	2,850		2,850
Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			(14)	(24)
Other comprehensive loss before reclassifications			(5)	3
Amounts reclassified from accumulated other comprehensive loss			(1)	3
Total other comprehensive (loss) income			(6)	6
Balance at end of period	(20)	(18)	(20)	(18)
Foreign Currency Translation
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			(38)	(50)
Other comprehensive loss before reclassifications			(6)	11
Amounts reclassified from accumulated other comprehensive loss			0	0
Total other comprehensive (loss) income			(6)	11
Balance at end of period	(44)	(39)	(44)	(39)
Other
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			(2)	(2)
Other comprehensive loss before reclassifications			0	0
Amounts reclassified from accumulated other comprehensive loss			0	0
Total other comprehensive (loss) income			0	0
Balance at end of period	(2)	(2)	(2)	(2)
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			(54)	(76)
Other comprehensive loss before reclassifications			(11)	14
Amounts reclassified from accumulated other comprehensive loss			(1)	3
Total other comprehensive (loss) income			(12)	17
Balance at end of period	$ (66)	$ (59)	$ (66)	$ (59)
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2017-12 | Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Cumulative-effect adjustment of ASU adoption					$ 3
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2017-12 | Foreign Currency Translation
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Cumulative-effect adjustment of ASU adoption					0
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2017-12 | Other
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Cumulative-effect adjustment of ASU adoption					0
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2017-12 | Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Cumulative-effect adjustment of ASU adoption					3
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2018-02 | Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Cumulative-effect adjustment of ASU adoption					(3)
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2018-02 | Foreign Currency Translation
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Cumulative-effect adjustment of ASU adoption					0
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2018-02 | Other
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Cumulative-effect adjustment of ASU adoption					0
New Accounting Pronouncement, Early Adoption, Effect | Accounting Standards Update 2018-02 | Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Cumulative-effect adjustment of ASU adoption					$ (3)