Leases - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) lease renewal_option	Dec. 31, 2019 USD ($)	Jan. 01, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets	$ 4	$ 4
Number of finance leases | lease	2
Present value of lease liabilities	$ 4
Unconditional payment obligations	$ 1	$ 5
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets			$ 5
Present value of lease liabilities			$ 5
Ten Year Agreement, Five Year Renewal Option
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Initial term	10 years
Additional term	5 years
Extension term prior to original extension option	14 months
Number of renewal options | renewal_option	2
Ten Year Agreement, One Year Renewal Option
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Additional term	1 year
Number of renewal options | renewal_option	10