Derivative Instruments (Schedule of Derivatives - Income Statement) (Details) - Other, Net - Not Designated as Hedging Instrument - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Foreign currency forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	$ (15)	$ (16)	$ (22)	$ 10
Warrant
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	$ 127	$ 0	$ 65	$ 0