Derivatives and Hedging - Notional and fair values of derivative instruments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value
Notional Amount	$ 766	$ 947
Derivative Assets	11	15
Derivative Liabilities	$ 13	14
Term of derivative contract	30 days
Other Current Assets
Derivatives, Fair Value
Derivative Assets	$ 2	6
Amount not offset against collateral, derivative asset	2	4
Other Noncurrent Assets
Derivatives, Fair Value
Derivative Assets	9	9
Amount not offset against collateral, derivative asset	8	9
Other Current Liabilities
Derivatives, Fair Value
Derivative Liabilities	5	7
Amount not offset against collateral, derivative liabilities	5	5
Other Noncurrent Liabilities
Derivatives, Fair Value
Derivative Liabilities	8	7
Amount not offset against collateral, derivative liabilities	6	7
Derivatives accounted for as hedges | Foreign exchange contracts
Derivatives, Fair Value
Notional Amount	523	758
Derivative Assets	10	14
Derivative Liabilities	11	13
Gross Amounts Offset in the Statement of Financial Position	0	(1)
Net Amounts of Assets Presented in the Statement of Financial Position	10	13
Gross Amounts Offset in the Statement of Financial Position	0	(1)
Net Amounts of Liabilities Presented in the Statement of Financial Position	11	12
Not Designated as Hedging Instrument | Foreign exchange contracts
Derivatives, Fair Value
Notional Amount	243	189
Derivative Assets	1	1
Derivative Liabilities	$ 2	$ 1