Financial Instruments - Summary of Derivative Instruments Fair Value (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Net Derivative Asset (Liability)	$ 158	$ 49
Other current assets [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Assets	172	62
Liabilities [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Liabilities	(14)	(13)
Senior Notes Due 2021 [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Assets	18
Derivatives Designated as Hedging Instruments [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Net Derivative Asset (Liability)	37	(1)
Derivatives Designated as Hedging Instruments [Member] | Other Assets [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Net Derivative Asset (Liability)	55	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	39	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	(2)	(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	0	(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	18	7
Not Designated as Hedging Instrument [Member] | Foreign exchange contracts - forwards [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Net Derivative Asset (Liability)	103	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	115	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	$ (12)	$ (8)