Financial Instruments, Summary of Derivative Instruments Fair Value (Details) (Foreign exchange contracts - forwards [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Net Derivative Asset (Liability)	$ (40)	$ (71)
Other current assets [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Assets	25	11
Other current liabilities [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Liabilities	(65)	(82)
Derivatives Designated as Hedging Instruments [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Net Derivative Asset (Liability)	(48)	(48)
Derivatives Designated as Hedging Instruments [Member] | Other current assets [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Assets	11	3
Derivatives Designated as Hedging Instruments [Member] | Other current liabilities [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Liabilities	(59)	(51)
Not Designated as Hedging Instrument [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Net Derivative Asset (Liability)	8	(23)
Not Designated as Hedging Instrument [Member] | Other current assets [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Assets	14	8
Not Designated as Hedging Instrument [Member] | Other current liabilities [Member]
Summary Of Derivative Instruments By Hedge Designation [Abstract]
Total Derivative Liabilities	$ (6)	$ (31)