Financial Guaranty Insurance Premiums Financial Guaranty Insurance Premiums (Details 2) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Financial Guaranty Insurance Premiums [Line Items]
Deferred premium revenue, gross	$ 4,947		$ 5,356
Deferred premium revenue, ceded	533		586
Deferred premium revenue, net	4,414	[1]	4,770	[1]
Unearned premium reserve	4,812		5,207
Prepaid Reinsurance Premiums	510		561
Unearned Premiums, Net	4,302	[1]	4,646	[1]
Total net unearned premium reserve related to FG VIE	210		262
Contra-paid related to FG and VIEs	58		98
Financial guaranty
Financial Guaranty Insurance Premiums [Line Items]
Deferred premium revenue, gross	4,941		5,349
Deferred premium revenue, ceded	533		586
Deferred premium revenue, net	4,408	[1]	4,763	[1]
Contra-paid, gross	(135)		(149)
Contra-paid, ceded	(23)		(25)
Contra-paid, net	(112)	[1]	(124)	[1]
Other
Financial Guaranty Insurance Premiums [Line Items]
Unearned premium reserve	6		7
Prepaid Reinsurance Premiums	0		0
Unearned Premiums, Net	$ 6	[1]	$ 7	[1]

[1] Excludes $210 million and $262 million of deferred premium revenue, and $58 million and $98 million of contra-paid related to FG VIEs as of June 30, 2013 and December 31, 2012, respectively.