Related Party Transactions - Schedule of Condensed Combined Statement of Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transactions [Abstract]
Allocated operating expenses	$ 45	$ 18	$ 15
Major maintenance costs	6	0	0
Insurance expense	20	18	15
Other	43	23	24
Operations and maintenance – related parties	114	59	54
Allocated general corporate expenses	29	28	33
Management Agreement fee	9	9	9
Omnibus Agreement fee	11	11	9
Other	0	1	1
General and administrative – related parties	$ 49	$ 49	$ 52