Fair Value Measurements - Additional Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Jun. 30, 2018 USD ($) Contract	Dec. 31, 2017 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of earn-out liability		$ 14		$ 14
Other operating income from earn out liability adjustment	$ 14	$ 13
Fair value of contingent consideration			$ 0
Foreign Exchange Swaps | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Maturity period of swap contracts			6 months
Foreign Exchange Swaps | Maturity Beyond Six Months
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number of foreign currency derivatives held | Contract			0