Leases - Additional Information (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
	Jan. 01, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Range [Axis] [Line Items]
Operating Lease, Weighted Average Remaining Lease Term		6 years		6 years
Lease extension option	5 years
Option to terminate period	1 year
Document Period End Date				Jun. 30, 2019
Operating lease expenses		$ 10	$ 8	$ 19	$ 15
Minimum [Member]
Range [Axis] [Line Items]
Operating Lease, Weighted Average Remaining Lease Term	1 year
Maximum [Member]
Range [Axis] [Line Items]
Operating Lease, Weighted Average Remaining Lease Term	11 years