Derivative Instruments (Schedule of Derivatives - Balance Sheet) (Details) (Not Designated as Hedging Instrument [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Foreign currency forward contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross	$ 5	$ 12
Foreign currency forward contracts [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, fair value, gross	(19)	(17)
Cross-currency swap contracts [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, fair value, gross	$ 0	$ (5)