Revenue Recognition - Contract Balances (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Movement in Deferred Revenue [Roll Forward]
Beginning balance	$ 8
Ending balance	0	$ 8
Third Parties
Movement in Deferred Revenue [Roll Forward]
Beginning balance	8	6
Transition Adjustment	0	0
Additions	0	10
Reductions	(8)	(8)
Ending balance	0	8
Related Parties
Movement in Deferred Revenue [Roll Forward]
Beginning balance	3	14
Transition Adjustment	0	(4)
Additions	0	3
Reductions	(3)	(10)
Ending balance	$ 0	$ 3