Outstanding Exposure - Puerto Rico Gross Par and Gross Debt Service Outstanding (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Schedule of Insured Financial Obligations [Line Items]
Gross Debt Service Outstanding	$ 460,932	$ 455,000
Puerto Rico [Member]
Schedule of Insured Financial Obligations [Line Items]
Gross par outstanding	5,435	5,435
Gross Debt Service Outstanding	$ 8,903	$ 9,038