Financial Guaranty Variable Interest Entities and Consolidated Investment Vehicles - Roll Forward of Number of Consolidated CIVs (Details) (Details) - Variable Interest Entity, Primary Beneficiary - Consolidated Investment Vehicles $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) Entity	Dec. 31, 2021 Entity	Dec. 31, 2020 Entity
Schedule of Consolidated FG VIEs Rollforward [Roll Forward]
Beginning of year	20	11	4
Consolidated	4	10	7
Deconsolidated	(2)	(1)	0
December 31		20	11
Deconsolidation, net assets | $	$ 417