Contracts Accounted for as Insurance - Gross Premium Receivable Net of Commissions on Assumed Business Roll Forward (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Gross Premium Receivable Net of Ceding Commissions [Roll Forward]
Beginning of year	$ 1,298	$ 1,372
Less: Specialty insurance premium receivable	1	1
Financial guaranty insurance premiums receivable	1,297	1,371
Gross written premiums on new business, net of commissions	171	137
Gross premiums received, net of commissions	(120)	(180)
Adjustments:
Changes in the expected term and debt service assumptions	9	(4)
Accretion of discount, net of commissions on assumed business	13	12
Foreign exchange gain (loss) on remeasurement	46	(102)
FG insurance premiums receivable	1,416	1,234
Specialty insurance premium receivable	1	1
Ending balance	$ 1,417	$ 1,235