Outstanding Insurance Exposure - Puerto Rico Gross Par and Gross Debt Service Outstanding (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Schedule of Insured Financial Obligations [Line Items]
Gross Debt Service Outstanding	$ 365,356	$ 375,776
Puerto Rico [Member]
Schedule of Insured Financial Obligations [Line Items]
Gross Par Outstanding	4,458	4,458
Gross Debt Service Outstanding	$ 6,845	$ 6,956