Financial Guaranty Insurance Losses - Reconciliation of Net Expected Loss to be Paid and Expensed (Details) - USD ($) $ in Millions		Jun. 30, 2015		Mar. 31, 2015	Dec. 31, 2014		Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Guarantor Obligations [Line Items]
Net expected loss to be paid after recoveries for R&W		$ 1,510	[1]	$ 1,154	$ 1,169	[1]	$ 1,035	$ 984	$ 982
Loss and LAE reserve, net of reinsurance	[2]	(919)			(721)
Other recoveries		8			13
Net expected loss to be expensed (present value)		421
Variable Interest Entity, Primary Beneficiary [Member]
Guarantor Obligations [Line Items]
Net expected loss to be expensed (present value)		82
Consolidated Entity Excluding Consolidation of Variable Interest Entities (VIE) [Member]
Guarantor Obligations [Line Items]
Contra-paid, net	[3],[4]	(83)			(100)
Financial Guarantee Insurance And Other Product Line [Member]
Guarantor Obligations [Line Items]
Net expected loss to be paid after recoveries for R&W		1,264
Contra-paid, net		(83)
Salvage and subrogation recoverable, net of reinsurance		132
Loss and LAE reserve, net of reinsurance		(900)
Other recoveries		8
Net expected loss to be expensed (present value)	[5]	421
Financial Guarantee Insurance And Other Product Line [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Guarantor Obligations [Line Items]
Loss and LAE reserve, net of reinsurance		70			80
Financial Guarantee Insurance And Other Product Line [Member] | Consolidated Entity Excluding Consolidation of Variable Interest Entities (VIE) [Member]
Guarantor Obligations [Line Items]
Net expected loss to be paid after recoveries for R&W		1,397
Loss and LAE reserve, net of reinsurance		(989)			$ (801)
Financial Guarantee Insurance And Other Product Line [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Guarantor Obligations [Line Items]
Net expected loss to be paid after recoveries for R&W		$ 133

[1] Includes expected LAE to be paid of $15 million as of June 30, 2015 and $16 million as of December 31, 2014.

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

[3] Excludes $125 million and $125 million of deferred premium revenue, and $37 million and $42 million of contra-paid related to FG VIEs as of June 30, 2015 and December 31, 2014, respectively.

[4] See Note 7, "Financial Guaranty Insurance Losses– Insurance Contracts' Loss Information" for an explanation of "contra-paid".

[5] Excludes $82 million as of June 30, 2015, related to consolidated FG VIEs.