Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	[1]
Supplemental Cash Flow Elements [Abstract]
Interest Paid, Excluding Capitalized Interest, Operating Activities	$ 117	$ 78
Operating Lease, Payments	8	0
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	2	0
Capital Expenditures Incurred but Not yet Paid	113	87
Receivable From Affiliate For Capital Expenditures	8	2
Finance Lease, Principal Payments	2	0
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	$ 1	$ 0

[1] Adjusted to include the historical results of the Predecessors. See Note 1 for further discussion.