Investment in Unconsolidated Entities - Schedule of Investments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity method investments	$ 487		$ 487		$ 467
Measurement alternative method investments	21		21		21
Total investments in unconsolidated entities	508	$ 511	508	$ 511	$ 488
Schedule of Equity Method Investments [Line Items]
Revenues	1,324	1,321	3,849	3,840
Operating expenses	1,237	1,292	3,611	3,669
Operating income	87	29	238	171
Other income (expense), net	0	0	(1)	0
Net income	93	23	254	132
Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Revenues	1,640	1,721	4,889	5,077
Operating expenses	1,142	1,247	3,407	3,660
Operating income	498	474	1,482	1,417
Other income (expense), net	(3)	(2)	(2)	(4)
Net income	$ 495	$ 472	$ 1,480	$ 1,413