Financial Instruments (Fair Value of Derivative Instruments) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Total foreign currency forward-exchange contracts	$ 21	$ (2)
Foreign Exchange Forward
Derivatives, Fair Value [Line Items]
Gain (loss) on derivative contracts not designated as hedging instruments	(24)	25
Foreign Exchange Forward \| Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Total foreign currency forward-exchange contracts	4	(2)
Foreign Exchange Forward \| Not Designated as Hedging Instrument \| Other current assets
Derivatives, Fair Value [Line Items]
Foreign currency forward-exchange contracts	12	8
Foreign Exchange Forward \| Not Designated as Hedging Instrument \| Other current liabilities
Derivatives, Fair Value [Line Items]
Foreign currency forward-exchange contracts	(8)	(10)
Interest Rate Swap \| Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Foreign currency forward-exchange contracts	17	0
Interest Rate Swap \| Designated as Hedging Instrument \| Other current assets
Derivatives, Fair Value [Line Items]
Foreign currency forward-exchange contracts	17	0
Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Net gains/ (losses) on derivative instruments designated as cash flow hedges	$ 10	$ 0

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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