Outstanding Exposure - Outstanding GO and PBA Bonds (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	$ 232,812	$ 236,392
Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	2,227	3,572
Puerto Rico Exposures Subject to a Plan or Support Agreement | Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	1,298	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	42	1,219
Puerto Rico Exposures Subject to a Plan or Support Agreement | GO | Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	37	1,097
Puerto Rico Exposures Subject to a Plan or Support Agreement | PBA | Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	5	$ 122
Direct | Puerto Rico Exposures Subject to a Plan or Support Agreement | GO/PBA PSA | Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	41
Direct | Puerto Rico Exposures Subject to a Plan or Support Agreement | GO | Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	36
Direct | Puerto Rico Exposures Subject to a Plan or Support Agreement | PBA | Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	5
Assumed | Puerto Rico Exposures Subject to a Plan or Support Agreement | GO/PBA PSA | Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	1
Assumed | Puerto Rico Exposures Subject to a Plan or Support Agreement | GO | Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	1
Assumed | Puerto Rico Exposures Subject to a Plan or Support Agreement | PBA | Puerto Rico
Financial Guaranty Insurance BIG Transaction Loss Summary
Net	$ 0