Contracts Accounted for as Insurance - Gross Premium Receivable Net of Commissions on Assumed Business Roll Forward (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Gross Premium Receivable Net of Ceding Commissions [Roll Forward]
Beginning of year	$ 1,468	$ 1,298
Less: Specialty insurance premium receivable	1	1
Financial guaranty insurance premiums receivable	1,467	1,297
Gross written premiums on new business, net of commissions	63	79
Gross premiums received, net of commissions	(75)	(64)
Adjustments:
Changes in the expected term and debt service assumptions	(3)	6
Accretion of discount, net of commissions on assumed business	7	7
Foreign exchange gain (loss) on remeasurement	(10)	20
FG insurance premiums receivable	1,449	1,345
Specialty insurance premium receivable	1	1
Ending balance	$ 1,450	$ 1,346