Equity Method Investments - Summary of Income Statement Data for Equity Method Investments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	$ 112	$ 70
Total revenue	121	131
Operating income	45	65
Amberjack
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	29	32
Total Revenues	76	81
Total Operating Expenses	19	19
Operating Income	57	62
Net Income	57	62
Mars
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	31	29
Total Revenues	72	63
Total Operating Expenses	28	22
Operating Income	44	41
Net Income	44	41
Bengal
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	5	5
Total Revenues	17	18
Total Operating Expenses	7	7
Operating Income	10	11
Net Income	10	11
Explorer
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	14	0
Total Revenues	96
Total Operating Expenses	47
Operating Income	49
Net Income	38
Colonial Pipeline Company (“Colonial”)
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	27	0
Total Revenues	401
Total Operating Expenses	163
Operating Income	238
Net Income	169
Poseidon
Schedule of Equity Method Investments [Line Items]
Total Revenues	33	31
Total Operating Expenses	9	9
Operating Income	24	22
Net Income	22	20
Other
Schedule of Equity Method Investments [Line Items]
Income from equity method investments	6	4
Total Revenues	57	30
Total Operating Expenses	27	18
Operating Income	30	12
Net Income	$ 25	$ 9