Equity Method Investments - Schedule of Equity Investments in Affiliates (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Schedule of Equity Method Investments [Line Items]
Investment Amount	$ 926,000,000	$ 823,000,000
Amberjack – Series A / Series B
Schedule of Equity Method Investments [Line Items]
Investment Amount	$ 433,000,000	$ 458,000,000
Amberjack - Series A
Schedule of Equity Method Investments [Line Items]
Ownership	75.00%	75.00%
Amberjack - Series B
Schedule of Equity Method Investments [Line Items]
Ownership	50.00%	50.00%
Mars
Schedule of Equity Method Investments [Line Items]
Ownership	71.50%	71.50%
Investment Amount	$ 162,000,000	$ 169,000,000
Bengal
Schedule of Equity Method Investments [Line Items]
Ownership	50.00%	50.00%
Investment Amount	$ 88,000,000	$ 82,000,000
Crestwood Permian Basin LLC (“Permian Basin”)
Schedule of Equity Method Investments [Line Items]
Ownership	50.00%	50.00%
Investment Amount	$ 81,000,000	$ 72,000,000
LOCAP
Schedule of Equity Method Investments [Line Items]
Ownership	41.48%	41.48%
Investment Amount	$ 9,000,000	$ 8,000,000
Explorer
Schedule of Equity Method Investments [Line Items]
Ownership	38.59%	12.62%
Investment Amount	$ 89,000,000	$ 0
Poseidon
Schedule of Equity Method Investments [Line Items]
Ownership	36.00%	36.00%
Investment Amount	$ 0	$ 0	$ 0
Colonial Pipeline Company (“Colonial”)
Schedule of Equity Method Investments [Line Items]
Ownership	16.125%	6.00%
Investment Amount	$ 31,000,000	$ 0
Proteus
Schedule of Equity Method Investments [Line Items]
Ownership	10.00%	10.00%
Investment Amount	$ 15,000,000	$ 16,000,000
Endymion
Schedule of Equity Method Investments [Line Items]
Ownership	10.00%	10.00%
Investment Amount	$ 18,000,000	$ 18,000,000