Financial Instruments Fair Value Of Foreign Exchange Contracts (Details) (Foreign Exchange Contract [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Foreign exchange contracts designated as hedging instruments, Asset Derivatives, Fair Value	$ 116	$ 145
Total Derivatives, Asset Derivatives, Fair Value	116	145
Foreign exchange contracts designated as hedging instruments, Liability Derivatives, Fair Value	38	66
Total Derivatives, Liability Derivatives, Fair Value	38	66
Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Foreign exchange contracts designated as hedging instruments, Asset Derivatives, Fair Value	91	57
Total Derivatives, Asset Derivatives, Fair Value	91	57
Designated as Hedging Instrument [Member] | Other Accrued Liabilities [Member]
Foreign exchange contracts designated as hedging instruments, Liability Derivatives, Fair Value	0	4
Total Derivatives, Liability Derivatives, Fair Value	0	4
Not Designated as Hedging Instrument [Member] | Other Current Assets [Member]
Foreign exchange contracts not designated as hedging instruments, Asset Derivatives, Fair Value	25	88
Not Designated as Hedging Instrument [Member] | Other Accrued Liabilities [Member]
Foreign exchange contracts not designated as hedging instruments, Liability Derivatives, Fair Value	36	62
Not Designated as Hedging Instrument [Member] | Non-current Liabilities [Member]
Foreign exchange contracts not designated as hedging instruments, Liability Derivatives, Fair Value	$ 2	$ 0