Outstanding Exposure - Outstanding GO and PBA Bonds (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	$ 227,071	$ 236,392
Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	2,071	3,572
Puerto Rico Exposures Subject to a Plan or Support Agreement | Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	1,218	2,643
Puerto Rico Exposures Subject to a Plan or Support Agreement | GO/PBA PSA | Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	29	1,219
Puerto Rico Exposures Subject to a Plan or Support Agreement | Commonwealth of Puerto Rico | Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	25	1,097
Puerto Rico Exposures Subject to a Plan or Support Agreement | Puerto Rico Public Buildings Authority | Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	$ 4	$ 122