Derivatives and Hedging - Offsetting of financial assets and derivatives assets (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Other Current Assets [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	$ 15	$ 24
Net Amounts of Assets Presented in the Statement of Financial Position	6	12
Other Noncurrent Assets [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	17	22
Net Amounts of Assets Presented in the Statement of Financial Position	13	20
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	32	46
Gross Amounts Offset in the Statement of Financial Position	(13)	(14)
Net Amounts of Assets Presented in the Statement of Financial Position	19	32
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	32	46
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Gross Amounts of Recognized Assets	$ 0	$ 0