Financial Instruments Cash Flow Hedges Included in AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Remaining Maturity	2 years
After-tax net gain to be reclassified from AOCL into earnings over the next twelve months	$ 4
Successor [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Additions and revaluations of derivatives designated as cash flow hedges	16
Predecessor [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Additions and revaluations of derivatives designated as cash flow hedges		$ 4
Cash Flow Hedging [Member] | Successor [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Beginning Balance	(2)
Additions and revaluations of derivatives designated as cash flow hedges	12
Clearance of hedge results to earnings	(1)
Ending Balance	$ 9
Cash Flow Hedging [Member] | Predecessor [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Beginning Balance		7
Additions and revaluations of derivatives designated as cash flow hedges		2
Clearance of hedge results to earnings		(5)
Ending Balance		$ 4