Equity Method Investments - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 06, 2019	Jun. 05, 2019	Jan. 01, 2019	Dec. 31, 2018	Mar. 31, 2018	Jan. 01, 2018
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 930,000,000		$ 930,000,000					$ 823,000,000
Unamortized basis differences included in equity investments	97,000,000		97,000,000					40,000,000
Amortization expense (income)	1,000,000	$ 1,000,000	2,000,000	$ 2,000,000
Cumulative effect to total (deficit)/equity							$ 9,000,000			$ 2,000,000
June 2019 Acquisition
Schedule of Equity Method Investments [Line Items]
Equity method investments					$ 90,000,000
Poseidon
Schedule of Equity Method Investments [Line Items]
Equity method investments	0		0					0	$ 0
Investment, excess distribution	9,000,000	$ 9,000,000	17,000,000	$ 10,000,000
Mars
Schedule of Equity Method Investments [Line Items]
Equity method investments	162,000,000		162,000,000					169,000,000
Mars | Accounting Standards Update 2016-01
Schedule of Equity Method Investments [Line Items]
Cumulative effect to total (deficit)/equity										$ 7,000,000
Amberjack – Series A / Series B
Schedule of Equity Method Investments [Line Items]
Equity method investments	441,000,000		441,000,000					458,000,000.0
Amberjack – Series A / Series B | Accounting Standards Update 2016-01
Schedule of Equity Method Investments [Line Items]
Cumulative effect to total (deficit)/equity							$ 9,000,000
Explorer
Schedule of Equity Method Investments [Line Items]
Equity method investments	92,000,000		92,000,000					0
Distributions Received			23,000,000
Colonial Pipeline Company (“Colonial”)
Schedule of Equity Method Investments [Line Items]
Equity method investments	30,000,000		30,000,000					0
Distributions Received			16,000,000
Explorer and Colonial
Schedule of Equity Method Investments [Line Items]
Other investments						$ 60,000,000
Crestwood Permian Basin LLC (“Permian Basin”)
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 79,000,000		79,000,000					$ 72,000,000
Capital contribution			$ 10,000,000