Equity Method Investments - Schedule of Equity Investments in Affiliates Balance Affected (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019	Jan. 01, 2018
Schedule of Equity Method Investments [Line Items]
Distributions Received	$ 83	$ 51
Income from equity method investments	70	40
Impact of Change in Accounting Policy			$ (9)	$ (2)
Amberjack
Schedule of Equity Method Investments [Line Items]
Distributions Received	37	0
Income from equity method investments	32	0
Mars
Schedule of Equity Method Investments [Line Items]
Distributions Received	31	32
Income from equity method investments	29	25
Bengal
Schedule of Equity Method Investments [Line Items]
Distributions Received	3	4
Income from equity method investments	5	4
Poseidon
Schedule of Equity Method Investments [Line Items]
Distributions Received	8	9
Income from equity method investments	0	6
Other
Schedule of Equity Method Investments [Line Items]
Distributions Received	4	6
Income from equity method investments	$ 4	$ 5
Accounting Standards Update 2016-01
Schedule of Equity Method Investments [Line Items]
Impact of Change in Accounting Policy			(9)	(7)
Accounting Standards Update 2016-01 | Amberjack
Schedule of Equity Method Investments [Line Items]
Impact of Change in Accounting Policy			(9)	0
Accounting Standards Update 2016-01 | Mars
Schedule of Equity Method Investments [Line Items]
Impact of Change in Accounting Policy			0	(7)
Accounting Standards Update 2016-01 | Bengal
Schedule of Equity Method Investments [Line Items]
Impact of Change in Accounting Policy			0	0
Accounting Standards Update 2016-01 | Poseidon
Schedule of Equity Method Investments [Line Items]
Impact of Change in Accounting Policy			0	0
Accounting Standards Update 2016-01 | Other
Schedule of Equity Method Investments [Line Items]
Impact of Change in Accounting Policy			$ 0	$ 0