Financial Instruments - Summary of Derivative Instruments Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Net Derivative Asset (Liability)	$ 57	$ 49
Other current assets [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Assets	84	62
Liabilities [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Liabilities	(27)	(13)
Senior Notes Due 2021 [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Assets	15
Derivatives Designated as Hedging Instruments [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Net Derivative Asset (Liability)	9	(1)
Derivatives Designated as Hedging Instruments [Member] | Liabilities [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Net Derivative Asset (Liability)	24	6
Derivatives Designated as Hedging Instruments [Member] | Foreign exchange contracts - forwards [Member] | Other current assets [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Assets	15	4
Derivatives Designated as Hedging Instruments [Member] | Foreign exchange contracts - forwards [Member] | Other current liabilities [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Liabilities	(5)	(4)
Derivatives Designated as Hedging Instruments [Member] | Currency options [Member] | Other current liabilities [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Liabilities	(1)	(1)
Derivatives Designated as Hedging Instruments [Member] | Interest rate swap [Member] | Other long-term assets [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Assets	15	7
Not Designated as Hedging Instrument [Member] | Foreign exchange contracts - forwards [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Net Derivative Asset (Liability)	33	43
Not Designated as Hedging Instrument [Member] | Foreign exchange contracts - forwards [Member] | Other current assets [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Assets	54	51
Not Designated as Hedging Instrument [Member] | Foreign exchange contracts - forwards [Member] | Other current liabilities [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Liabilities	$ (21)	$ (8)