Outstanding Exposure - Debt Service Outstanding (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Schedule of Insured Financial Obligations [Line Items]
Gross Debt Service Outstanding	$ 611,993	$ 646,722
Net Debt Service Outstanding	584,428	609,622
Public Finance [Member]
Schedule of Insured Financial Obligations [Line Items]
Gross Debt Service Outstanding	557,816	587,245
Net Debt Service Outstanding	532,992	553,612
Structured Finance [Member]
Schedule of Insured Financial Obligations [Line Items]
Gross Debt Service Outstanding	54,177	59,477
Net Debt Service Outstanding	$ 51,436	$ 56,010