Equity Method Investments - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jun. 06, 2019	Jun. 05, 2019	Jan. 01, 2019	Jun. 30, 2018	Jan. 01, 2018	Dec. 01, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 926,000,000	$ 926,000,000	$ 823,000,000
Unamortized basis differences included in equity investments	92,000,000	92,000,000	40,000,000	$ 41,000,000
Amortization expense		6,000,000	4,000,000	4,000,000
Income from equity method investments		373,000,000	235,000,000	187,000,000
Impact of changes in accounting policy							$ (9,000,000)		$ (2,000,000)
Shell Pipeline Company L P
Schedule of Equity Method Investments [Line Items]
Cash received		19,000,000	12,000,000	16,000,000
Mars Oil Pipeline Company LLC (“Mars”) | Shell Pipeline Company L P
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership interest acquired											20.00%
Consideration to be received if inventory management fees do now meet certain levels											$ 10,000,000
June 2019 Acquisition
Schedule of Equity Method Investments [Line Items]
Equity method investments					$ 90,000,000
Poseidon Oil Pipeline Company, L.L.C. (“Poseidon”)
Schedule of Equity Method Investments [Line Items]
Equity method investments	0	0	0					$ 0
Investment, excess distribution		33,000,000	24,000,000
Income from equity method investments		0	6,000,000	27,000,000
Mars Oil Pipeline Company LLC (“Mars”)
Schedule of Equity Method Investments [Line Items]
Equity method investments	161,000,000	161,000,000	169,000,000
Income from equity method investments		126,000,000	108,000,000	$ 122,000,000
Mars Oil Pipeline Company LLC (“Mars”) | Shell Pipeline Company L P
Schedule of Equity Method Investments [Line Items]
Cash received	9,000,000
Mars Oil Pipeline Company LLC (“Mars”) | Accounting Standards Update 2014-09
Schedule of Equity Method Investments [Line Items]
Impact of changes in accounting policy							$ (9,000,000)		$ (7,000,000)
Mars Oil Pipeline Company LLC (“Mars”) | December 2017 Acquisition
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership interest acquired				22.90%
Amberjack
Schedule of Equity Method Investments [Line Items]
Equity method investments	426,000,000	426,000,000	458,000,000
Income from equity method investments		125,000,000	80,000,000	$ 0
Explorer
Schedule of Equity Method Investments [Line Items]
Equity method investments	88,000,000	88,000,000	0
Income from equity method investments		41,000,000	0	0
Explorer | June 2019 Acquisition
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership interest acquired					25.97%
Explorer | December 2017 Acquisition
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership interest acquired										10.00%
Colonial
Schedule of Equity Method Investments [Line Items]
Equity method investments	30,000,000	30,000,000	0
Income from equity method investments		40,000,000	0	0
Colonial | June 2019 Acquisition
Schedule of Equity Method Investments [Line Items]
Equity method investments, ownership interest acquired					10.125%
Permian Basin
Schedule of Equity Method Investments [Line Items]
Equity method investments	91,000,000	91,000,000	72,000,000
Capital contribution		25,000,000	28,000,000
Other
Schedule of Equity Method Investments [Line Items]
Income from equity method investments		17,000,000	20,000,000	15,000,000
Explorer And Colonial
Schedule of Equity Method Investments [Line Items]
Other Investments						$ 60,000,000
Bengal
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 88,000,000	88,000,000	82,000,000
Income from equity method investments		$ 24,000,000	$ 21,000,000	$ 23,000,000