Outstanding Exposure - Puerto Rico Gross Par and Gross Debt Service Outstanding (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Schedule of Insured Financial Obligations [Line Items]
Insured Financial Obligations Outstanding Principal Amount, Gross	$ 233,438	$ 236,765
Gross	370,172	367,770
Puerto Rico
Schedule of Insured Financial Obligations [Line Items]
Insured Financial Obligations Outstanding Principal Amount, Gross	1,378	3,629
Gross	$ 1,899	$ 5,322