Financial Instruments Cash Flow Hedges Included in AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Remaining Maturity	2 years
Additions and revaluations of derivatives designated as cash flow hedges	$ 8	$ 16
After-tax net loss to be reclassified from AOCL into earnings over the next twelve months	10
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Beginning Balance	(26)	(2)
Additions and revaluations of derivatives designated as cash flow hedges	4	12
Clearance of hedge results to earnings	(3)	(1)
Ending Balance	$ (25)	$ 9