Derivative Financial Instruments and Cash Flow Hedging Strategy Fair Value of Derivatives - Balance Sheet (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	$ 13	$ 14	$ 3
Foreign Exchange Forward [Member] | Cash Flow Hedging [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Foreign Currency Derivative Assets at Fair Value	11		6
Foreign Exchange Forward [Member] | Cash Flow Hedging [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Foreign Currency Derivative Liabilities at Fair Value	1		3
Other Comprehensive Income (Loss) [Member]
Derivatives, Fair Value [Line Items]
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	$ 13		$ 3