Derivatives and Hedging - Offsetting of financial liabilities and derivative liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Other Current Liabilities [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	$ 13	$ 52
Net Amounts of Liabilities Presented in the Statement of Financial Position (2)	4	40
Other Noncurrent Liabilities [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	5	6
Net Amounts of Liabilities Presented in the Statement of Financial Position (2)	1	4
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	18	58
Gross Amounts Offset in the Statement of Financial Position	(13)	(14)
Net Amounts of Liabilities Presented in the Statement of Financial Position (2)	5	44
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	18	58
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Gross Amounts of Recognized Liabilities	$ 0	$ 0