Financial Instruments - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investments Debt And Equity Securities [Abstract]
Financial instruments including money market funds maturities period	90 days	90 days
Maximum maturities period of long-term marketable securities	3 years	3 years
Minimum maturities period of long-term marketable securities	1 year	1 year
Maximum remaining maturity for short-term marketable securities	12 months	12 months
Minimum maturities of short-term marketable securities	90 days	90 days
Net gain related to forward contracts	$ 2	$ 2	$ 1
Derivative instruments not designated as hedging instruments, description of terms	Our current forward contracts are not designated as hedges and have current maturities of less than 90 days
Cost method investments	$ 14	$ 0