Derivatives and Hedging - Notional and fair values of derivative instruments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Other Current Assets
Derivative [Line Items]
Derivative assets	$ 6	$ 15
Other Noncurrent Assets
Derivative [Line Items]
Derivative assets	9	17
Other Current Liabilities
Derivative [Line Items]
Derivative liabilities	7	13
Other Noncurrent Liabilities
Derivative [Line Items]
Derivative liabilities	7	5
Designated as Hedging Instrument | Foreign exchange contracts
Derivative [Line Items]
Notional amount	758	778
Derivative assets	14	32
Derivative liabilities	13	18
Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	947	1,058
Derivative assets	15	32
Derivative liabilities	14	18
Not Designated as Hedging Instrument | Foreign exchange contracts
Derivative [Line Items]
Notional amount	189	280
Derivative assets	1	0
Derivative liabilities	$ 1	$ 0
Term of contract ( in days)	30 days