Financial Instruments Cash Flow Hedges Included in AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Remaining Maturity			2 years
After-tax net loss to be reclassified from AOCL into earnings over the next twelve months			$ 5
Successor [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Additions and revaluations of derivatives designated as cash flow hedges	$ (15)		1
Predecessor [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Additions and revaluations of derivatives designated as cash flow hedges		$ 0		$ 4
Cash Flow Hedging [Member] | Successor [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Beginning Balance	9		(2)
Additions and revaluations of derivatives designated as cash flow hedges	(12)		0
Clearance of hedge results to earnings	(4)		(5)
Ending Balance	$ (7)		$ (7)
Cash Flow Hedging [Member] | Predecessor [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Beginning Balance		4		7
Additions and revaluations of derivatives designated as cash flow hedges		0		2
Clearance of hedge results to earnings		(8)		(13)
Ending Balance		$ (4)		$ (4)