Outstanding Exposure (Details 1) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Financial guarantee obligations
Gross Debt Service Outstanding	$ 776,546	$ 834,950
Net Debt Service Outstanding	727,997	782,180
Mortgage Guaranty Insured Obligations Outstanding Principal Amount	148
Public finance
Financial guarantee obligations
Gross Debt Service Outstanding	678,792	722,562
Net Debt Service Outstanding	637,104	677,369
Structured finance
Financial guarantee obligations
Gross Debt Service Outstanding	97,754	112,388
Net Debt Service Outstanding	90,893	104,811
Public finance Ireland
Financial guarantee obligations
Mortgage Guaranty Insured Obligations Outstanding Principal Amount	137
Public finance UK
Financial guarantee obligations
Mortgage Guaranty Insured Obligations Outstanding Principal Amount	$ 11