Financial Instruments (Details) - Fair Value, Measurements, Recurring - Not Designated as Hedging Instrument - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives	$ 4		$ 4		$ 12
Liability Derivatives	2		2		10
Interest rate instruments | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives	2		2		9
Liability Derivatives	1		1		9
Foreign currency forward contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amount of Gain or (Loss) Recognized in Income on Derivatives	(1)	$ (12)	0	$ (15)
Foreign currency forward contracts | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives	2		2		3
Liability Derivatives	$ 1		$ 1		$ 1