Revenues Revenue Recognition, Narrative (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018		Jun. 30, 2019	Jun. 30, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 3,800			$ 3,800
Contract with Customer, Liability, Revenue Recognized	7	$ 6		18	$ 20
Revenue from Contract with Customer, Including Assessed Tax	469	478	[1]	963	937	[1]
Operating Leases, Income Statement, Lease Revenue	$ 132	$ 91	[1]	$ 268	$ 178	[1]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	5 years			5 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Percent	85.00%			85.00%
Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	1 year			1 year
Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	15 years			15 years

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