Insurance Regulatory Restrictions Additional Details (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Average Annual Rate Of Return	3.22%	5.28%
Prescribed Discount Rate Percentage	5.10%
Minimum [Member]
Settlement Agreement Annual Restricted Payment Amount	$ 5
Maximum [Member]
Settlement Agreement Annual Restricted Payment Amount	8
Ambac Assurance [Member]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	598	$ 757
Ambac Assurance [Member] | Prescribed Or Permitted Additional Accounting Practices [Member]
Statutory Accounting Practices, Prescribed Practice, Amount	90	(5)
Everspan Indemnity
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	107	$ 106
Everspan Indemnity | Prescribed Or Permitted Additional Accounting Practices [Member]
Statutory Accounting Practices, Prescribed Practice, Amount	$ 18