Leases - Additional Information (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Jan. 01, 2019
Leases [Abstract]
Right-of-use assets	$ 21,000,000	$ 21,000,000	$ 14,000,000
Current lease liabilities	4,000,000	4,000,000	4,000,000
Non-current lease liabilities	$ 16,000,000	$ 16,000,000	$ 9,000,000
Discount rate	4.35%	4.35%
Remaining lease term	6 years 10 months 20 days	6 years 10 months 20 days
Operating expense	$ 1,000,000	$ 4,000,000
Short term operating lease expense	0	0
New ROU assets	$ 2,000,000	$ 10,000,000