Financial Guaranty Insurance Contracts (Details 5) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012 Payment		Dec. 31, 2011		Sep. 30, 2012 Financial Guaranty		Jun. 30, 2012 Financial Guaranty	Dec. 31, 2011 Financial Guaranty		Sep. 30, 2011 Financial Guaranty	Jun. 30, 2011 Financial Guaranty	Dec. 31, 2010 Financial Guaranty	Sep. 30, 2012 Financial Guaranty Total first lien		Jun. 30, 2012 Financial Guaranty Total first lien	Dec. 31, 2011 Financial Guaranty Total first lien		Sep. 30, 2011 Financial Guaranty Total first lien	Jun. 30, 2011 Financial Guaranty Total first lien	Dec. 31, 2010 Financial Guaranty Total first lien	Sep. 30, 2012 Financial Guaranty Second lien		Jun. 30, 2012 Financial Guaranty Second lien	Dec. 31, 2011 Financial Guaranty Second lien		Sep. 30, 2011 Financial Guaranty Second lien	Jun. 30, 2011 Financial Guaranty Second lien	Dec. 31, 2010 Financial Guaranty Second lien	Sep. 30, 2012 Financial Guaranty Residential, Subprime, Financing Receivable [Member]		Jun. 30, 2012 Financial Guaranty Residential, Subprime, Financing Receivable [Member]	Dec. 31, 2011 Financial Guaranty Residential, Subprime, Financing Receivable [Member]		Sep. 30, 2011 Financial Guaranty Residential, Subprime, Financing Receivable [Member]	Jun. 30, 2011 Financial Guaranty Residential, Subprime, Financing Receivable [Member]	Dec. 31, 2010 Financial Guaranty Residential, Subprime, Financing Receivable [Member]	Sep. 30, 2012 Other		Jun. 30, 2012 Other	Dec. 31, 2011 Other		Sep. 30, 2011 Other	Jun. 30, 2011 Other	Dec. 31, 2010 Other	Sep. 30, 2012 Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]		Dec. 31, 2011 Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Reconciliation of Expected Loss to be Paid and Net Expected Loss to be Expensed
Net Expected Loss to be Paid	$ 398				$ 398	[1]	$ 826	$ 638	[1]	$ 773	$ 713	$ 409	$ 240	[1]	$ 318	$ 430	[1]	$ 590	$ 599	$ 910	$ (128)	[1]	$ (80)	$ (111)	[1]	$ (119)	$ (133)	$ (749)	$ 165	[1]	$ 159	$ 140	[1]	$ 197	$ 162	$ 201	$ (4)	[1]	$ (4)	$ 2	[1]	$ 2	$ 2	$ 2
Less: net expected loss to be paid for FG VIEs	81
Net Expected Loss to be Paid Excluding VIEs																																													479
Contra-paid, net					126	[2]		73	[2]																																				126
FInancial Guaranty Insurance Contra Prepaid Losses related to CWALT, Net																																													30	[3],[4]	0	[3]
Salvage and Subrogation Recoverable Payable, Net	383	[5]	327	[5]																																									424
Ceded salvage and subrogation recoverable	(47)	[6]	(41)	[6]																																									(47)	[7]
Loss and LAE reserve																																													(591)
Reinsurance recoverable on unpaid losses	(56)		(69)																																										55
Total present value basis					476	[8],[9]																																							476
Net expected loss to be expensed related to consolidated financial guaranty VIEs	$ 195
Maximum number of payments behind to be considered performing borrower	1

[1] Includes expected LAE to be paid for mitigating claim liabilities of $26 million as of September 30, 2012 and $36 million as of December 31, 2011.

[2] Total net unearned premium reserve excludes $226 million and $274 million related to FG VIEs as of September 30, 2012 and December 31, 2011, respectively.

[3] R&W recoveries recorded in other assets on the consolidated balance sheet.

[4] Recorded in reinsurance balances payable on the consolidated balance sheet.

[5] See “Components of Net Reserves (Salvage)” table for loss and LAE reserve and salvage and subrogation recoverable components.

[6] Recorded as a component of reinsurance balances payable.

[7] xcludes $195 million related to consolidated FG VIEs.

[8] Consolidation of FG VIEs resulted in reductions of $364 million in future scheduled net earned premium and $195 million in net expected loss to be expensed.

[9] Balances represent discounted amounts.