Equity Method Investments - Summary of Income Statement Data for Equity Method Investments (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	$ 109		$ 80		$ 221	$ 150
Total revenue	120		121		241	252
Costs and Expenses	79		73		155	139
Operating Income (Loss)	41		48		86	113
Net income	144	$ 142	119	$ 137	286	256
April 2020 Acquisition
Schedule of Equity Method Investments [Line Items]
Total revenue					40
Costs and Expenses					6
Operating Income (Loss)					34
Amberjack
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	29		31		58	63
Amberjack | Equity Method Investment, Nonconsolidated Investee, Other
Schedule of Equity Method Investments [Line Items]
Total revenue	74		74		150	155
Costs and Expenses	17		17		36	36
Operating Income (Loss)	57		57		114	119
Net income	56		58		113	120
Mars
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	28		29		59	58
Mars | Equity Method Investment, Nonconsolidated Investee, Other
Schedule of Equity Method Investments [Line Items]
Total revenue	61		67		133	130
Costs and Expenses	21		26		49	48
Operating Income (Loss)	40		41		84	82
Net income	40		42		84	83
Bengal
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	4		5		9	10
Bengal | Equity Method Investment, Nonconsolidated Investee, Other
Schedule of Equity Method Investments [Line Items]
Total revenue	15		19		32	37
Costs and Expenses	8		9		15	16
Operating Income (Loss)	7		10		17	21
Net income	7		10		17	21
Explorer
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	10		7		24	7
Explorer | Equity Method Investment, Nonconsolidated Investee, Other
Schedule of Equity Method Investments [Line Items]
Total revenue	80		37		176	37
Costs and Expenses	43		13		90	13
Operating Income (Loss)	37		24		86	24
Net income	28		18		66	18
Explorer | Equity Method Investment, Nonconsolidated Investee, Other | June 2019 Acquisition
Schedule of Equity Method Investments [Line Items]
Total revenue			133			222
Costs and Expenses			48			94
Operating Income (Loss)			85			128
Colonial Pipeline Company (“Colonial”)
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	18		4		45	4
Colonial Pipeline Company (“Colonial”) | Equity Method Investment, Nonconsolidated Investee, Other
Schedule of Equity Method Investments [Line Items]
Total revenue	348		88		749	88
Costs and Expenses	166		44		329	44
Operating Income (Loss)	182		44		420	44
Net income	116		27		285	27
Colonial Pipeline Company (“Colonial”) | Equity Method Investment, Nonconsolidated Investee, Other | June 2019 Acquisition
Schedule of Equity Method Investments [Line Items]
Total revenue			325			696
Costs and Expenses			164			330
Operating Income (Loss)			161			366
Poseidon | Equity Method Investment, Nonconsolidated Investee, Other
Schedule of Equity Method Investments [Line Items]
Total revenue	30		34		63	65
Costs and Expenses	8		8		17	17
Operating Income (Loss)	22		26		46	48
Net income	20		23		42	43
Other
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	5		4		11	8
Other | Equity Method Investment, Nonconsolidated Investee, Other
Schedule of Equity Method Investments [Line Items]
Total revenue	57		56		114	86
Costs and Expenses	29		37		56	55
Operating Income (Loss)	28		19		58	31
Net income	23		17		48	26
Mattox
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	15		$ 0		15	$ 0
Mattox | Equity Method Investment, Nonconsolidated Investee, Other
Schedule of Equity Method Investments [Line Items]
Total revenue	22				22
Costs and Expenses	3				3
Operating Income (Loss)	19				19
Net income	$ 19				$ 19