Outstanding Exposure - Below-Investment-Grade Net Par Outstanding and Number of Risks (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013 risk		Dec. 31, 2012
Financial guarantee obligations
% of Total Net Par Outstanding	100.00%
Net Par Outstanding, Credit Derivative	$ 54,482		$ 70,781
Net Par Outstanding (excluding loss mitigation bonds)	459,107	[1]	518,772	[1]
Number of Risks	14,050
Prime first lien
Financial guarantee obligations
Net Par Outstanding, Credit Derivative	264		333
Net Par Outstanding (excluding loss mitigation bonds)	541		641
Alt-A first lien
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	3,590		4,469
Option ARM
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	937		1,450
Subprime
Financial guarantee obligations
Net Par Outstanding, Credit Derivative	2,930		3,494
Net Par Outstanding (excluding loss mitigation bonds)	6,130		7,048
Closed-end second lien
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	244		348
HELOCs
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	2,279		3,079
U.S. RMBS
Financial guarantee obligations
Net Par Outstanding, Credit Derivative	5,826		7,257
Net Par Outstanding (excluding loss mitigation bonds)	13,721		17,035
TruPS
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	4,970		5,694
Other structured finance
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	54,237		70,574
U.S. Public Finance
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	352,181	[1]	387,929	[1]
Non-U.S. public finance
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	33,998	[1]	37,540	[1]
BIG 1
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	14,751		10,820
BIG 1 | Prime first lien
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	52		28
BIG 1 | Alt-A first lien
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	656		753
BIG 1 | Option ARM
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	71		333
BIG 1 | Subprime
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	297		152
BIG 1 | Closed-end second lien
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	8		97
BIG 1 | HELOCs
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	1,499		644
BIG 1 | U.S. RMBS
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	2,583		2,007
BIG 1 | TruPS
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	1,587		1,920
BIG 1 | Other structured finance
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	1,367		1,310
BIG 1 | U.S. Public Finance
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	8,205		3,290
BIG 1 | Non-U.S. public finance
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	1,009		2,293
BIG 2
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	3,949		4,617
BIG 2 | Prime first lien
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	321		436
BIG 2 | Alt-A first lien
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	1,137		1,962
BIG 2 | Option ARM
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	60		392
BIG 2 | Subprime
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	908		988
BIG 2 | Closed-end second lien
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	20		76
BIG 2 | HELOCs
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	20		0
BIG 2 | U.S. RMBS
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	2,466		3,854
BIG 2 | TruPS
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	135		0
BIG 2 | Other structured finance
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	309		263
BIG 2 | U.S. Public Finance
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	440		500
BIG 2 | Non-U.S. public finance
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	599		0
BIG 3
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	3,838		6,860
BIG 3 | Prime first lien
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	30		11
BIG 3 | Alt-A first lien
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	935		739
BIG 3 | Option ARM
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	467		317
BIG 3 | Subprime
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	740		921
BIG 3 | Closed-end second lien
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	118		58
BIG 3 | HELOCs
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	378		1,932
BIG 3 | U.S. RMBS
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	2,668		3,978
BIG 3 | TruPS
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	0		953
BIG 3 | Other structured finance
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	721		1,154
BIG 3 | U.S. Public Finance
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	449		775
BIG 3 | Non-U.S. public finance
Financial guarantee obligations
Net Par Outstanding (excluding loss mitigation bonds)	0		0
BIG
Financial guarantee obligations
% of Total Net Par Outstanding	4.90%		4.30%
Net Par Outstanding, Financial Guaranty Insurance	17,745	[2]	15,588	[2]
Net Par Outstanding, Credit Derivative	4,793		6,709
Net Par Outstanding (excluding loss mitigation bonds)	22,538	[1]	22,297	[1]
Number of Risks, Financial Guaranty Insurance	384	[2],[3]	370	[2],[3]
Number of Risks, Credit Derivative	73	[3]	89	[3]
Number of Risks	457	[3]	459	[3]
BIG | Prime first lien
Financial guarantee obligations
% of Total Net Par Outstanding	0.10%		0.10%
Net Par Outstanding (excluding loss mitigation bonds)	403		475
BIG | Alt-A first lien
Financial guarantee obligations
% of Total Net Par Outstanding	0.60%		0.70%
Net Par Outstanding (excluding loss mitigation bonds)	2,728		3,454
BIG | Option ARM
Financial guarantee obligations
% of Total Net Par Outstanding	0.10%		0.20%
Net Par Outstanding (excluding loss mitigation bonds)	598		1,042
BIG | Subprime
Financial guarantee obligations
% of Total Net Par Outstanding	0.40%		0.40%
Net Par Outstanding (excluding loss mitigation bonds)	1,945		2,061
BIG | Closed-end second lien
Financial guarantee obligations
% of Total Net Par Outstanding	0.00%		0.00%
Net Par Outstanding (excluding loss mitigation bonds)	146		231
BIG | HELOCs
Financial guarantee obligations
% of Total Net Par Outstanding	0.40%		0.50%
Net Par Outstanding (excluding loss mitigation bonds)	1,897		2,576
BIG | U.S. RMBS
Financial guarantee obligations
% of Total Net Par Outstanding	1.60%		1.90%
Net Par Outstanding (excluding loss mitigation bonds)	7,717		9,839
BIG | TruPS
Financial guarantee obligations
% of Total Net Par Outstanding	0.40%		0.60%
Net Par Outstanding (excluding loss mitigation bonds)	1,722		2,873
BIG | Other structured finance
Financial guarantee obligations
% of Total Net Par Outstanding	0.50%		0.50%
Net Par Outstanding (excluding loss mitigation bonds)	2,397		2,727
BIG | U.S. Public Finance
Financial guarantee obligations
% of Total Net Par Outstanding	2.00%		0.90%
Net Par Outstanding (excluding loss mitigation bonds)	9,094	[1]	4,565	[1]
BIG | Non-U.S. public finance
Financial guarantee obligations
% of Total Net Par Outstanding	0.40%		0.40%
Net Par Outstanding (excluding loss mitigation bonds)	1,608	[1]	2,293	[1]
BIG | BIG 1
Financial guarantee obligations
Net Par Outstanding, Financial Guaranty Insurance	12,391	[2]	7,929	[2]
Net Par Outstanding, Credit Derivative	2,360		2,891
Net Par Outstanding (excluding loss mitigation bonds)	14,751		10,820
Number of Risks, Financial Guaranty Insurance	185	[2],[3]	163	[2],[3]
Number of Risks, Credit Derivative	25	[3]	33	[3]
Number of Risks	210	[3]	196	[3]
BIG | BIG 2
Financial guarantee obligations
Net Par Outstanding, Financial Guaranty Insurance	2,323	[2]	2,116	[2]
Net Par Outstanding, Credit Derivative	1,626		2,501
Net Par Outstanding (excluding loss mitigation bonds)	3,949		4,617
Number of Risks, Financial Guaranty Insurance	80	[2],[3]	76	[2],[3]
Number of Risks, Credit Derivative	21	[3]	27	[3]
Number of Risks	101	[3]	103	[3]
BIG | BIG 3
Financial guarantee obligations
Net Par Outstanding, Financial Guaranty Insurance	3,031	[2]	5,543	[2]
Net Par Outstanding, Credit Derivative	807		1,317
Net Par Outstanding (excluding loss mitigation bonds)	$ 3,838		$ 6,860
Number of Risks, Financial Guaranty Insurance	119	[2],[3]	131	[2],[3]
Number of Risks, Credit Derivative	27	[3]	29	[3]
Number of Risks	146	[3]	160	[3]

[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.

[2] Includes net par outstanding for FG VIEs.

[3] A risk represents the aggregate of the financial guaranty policies that share the same revenue source for purposes of making Debt Service payments.