Basis of Presentation and Significant Accounting Policies Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended	12 Months Ended
	Apr. 29, 1991	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2015	Jun. 30, 2020	Jul. 01, 2019	Dec. 31, 2018	Apr. 30, 2013
Finite-Lived Intangible Assets [Line Items]
Operating Lease, Liability		$ 28	$ 28	$ 30
Income Taxes Paid			$ 15	$ 11	$ 21
Common Stock Voting Restrictions	10.00%
Common Stock, Par or Stated Value Per Share										$ 0.01
Entity Incorporation, Date of Incorporation	Apr. 29, 1991
Preferred stock, shares authorized		20,000,000	20,000,000	20,000,000
Preferred Stock, Par or Stated Value Per Share		$ 0.01	$ 0.01							$ 0.01
Common stock, shares issued		46,477,068	46,477,068	45,865,081
Warrant Exercised During Period Shares			132	34	0
Common Stock Transfer Restrictions	5.00%
Common Stock Additional Transfer Restrictions						5.00%
Cash and cash equivalents		$ 17	$ 17	$ 20	$ 24
Restricted Cash		5	5	13	55
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		23	23	35	81				$ 83
UK Income Tax Rate							17.00%	19.00%
Restricted Cash		$ 5	$ 5	$ 13	55
Weighted average period of future premiums			8 years	8 years 3 months 18 days
Estimated Future Premium Payments Weighted Average Discounted Rate		2.20%	2.20%	2.20%
Business Combination, Redeemable Noncontrolling Percentage		20.00%	20.00%
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Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life		14 years
Restricted Cash		$ 5	$ 5	$ 4
Restricted Cash		5	$ 5	4
Minimum [Member] | Furniture and Fixtures [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			3 years
Maximum [Member] | Furniture and Fixtures [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			5 years
Long-term Debt [Member]
Finite-Lived Intangible Assets [Line Items]
Interest Paid, Including Capitalized Interest, Operating and Investing Activities			$ 80	107	143
Fixed Income Securities [Member]
Investment income due and accrued		10	10	10
Investment income due and accrued		10	10	10
Variable Interest Entity, Primary Beneficiary [Member]
Finite-Lived Intangible Assets [Line Items]
Restricted Cash		2	2	2	2
Restricted Cash		$ 2	$ 2	$ 2	$ 2
Estimated Future Premium Payments Weighted Average Discounted Rate		3.00%	3.00%	2.40%