Outstanding Exposure - Effect of Refinement in Approach to Internal Credit Ratings and Surveillance Categories on Net Par Outstanding (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)	$ 459,107	[1]	$ 518,772	[1]
BIG 1
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)	14,751		10,820
BIG 2
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)	3,949		4,617
BIG 3
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)	3,838		6,860
Previous Approach | BIG 1
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)			9,254
Previous Approach | BIG 2
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)			4,617
Previous Approach | BIG 3
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)			8,451
New Approach | BIG 1
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)			10,820
New Approach | BIG 2
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)			4,617
New Approach | BIG 3
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)			6,860
Difference | BIG 1
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)			1,566
Difference | BIG 2
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)			0
Difference | BIG 3
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)			(1,591)
BIG
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)	22,538	[1]	22,297	[1]
BIG | BIG 1
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)	14,751		10,820
BIG | BIG 2
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)	3,949		4,617
BIG | BIG 3
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)	3,838		6,860
BIG | Previous Approach
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)			22,322
BIG | New Approach
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)			22,297
BIG | Difference
Guarantor Obligations [Line Items]
Net Par Outstanding (excluding loss mitigation bonds)			$ (25)

[1] In the third quarter of 2013, the Company adjusted its approach to assigning internal ratings. See "Refinement of Approach to Internal Credit Ratings and Surveillance Categories" above. This approach is reflected in the "Financial Guaranty Portfolio by Internal Rating" tables as of both December 31, 2013 and December 31, 2012.