Outstanding Insurance Exposure - Debt Service Outstanding (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Schedule of Insured Financial Obligations [Line Items]
Gross Debt Service Outstanding	$ 363,462	$ 375,776
Net Debt Service Outstanding	362,529	374,130
Public Finance [Member]
Schedule of Insured Financial Obligations [Line Items]
Gross Debt Service Outstanding	352,266	363,497
Net Debt Service Outstanding	351,835	362,361
Structured Finance [Member]
Schedule of Insured Financial Obligations [Line Items]
Gross Debt Service Outstanding	11,196	12,279
Net Debt Service Outstanding	$ 10,694	$ 11,769