Financial Guaranty Insurance Losses - Components of Net Reserves (Salvage) Insurance Contracts (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Liability for Claims and Claims Adjustment Expense Including Salvage and Subrogation Recoverable [Line Items]
Loss and LAE reserve	$ 787		$ 799
Reinsurance recoverable on unpaid losses	(77)		(78)
Loss and LAE reserve, net	710	[1]	721	[1]
Salvage and subrogation recoverable	(128)		(151)
Salvage and subrogation payable	7	[2]	10	[2]
Other recoveries	(7)		(13)
Salvage and subrogation recoverable, net and other recoverable	(128)		(154)
Net reserves (salvage) - financial guaranty	582		567
Other Insurance Product Line [Member]
Liability for Claims and Claims Adjustment Expense Including Salvage and Subrogation Recoverable [Line Items]
Loss and LAE reserve, net	1		2
Net reserves (salvage) - financial guaranty	1		(4)
Financial Guarantee Insurance Product Line [Member]
Liability for Claims and Claims Adjustment Expense Including Salvage and Subrogation Recoverable [Line Items]
Loss and LAE reserve, net	709		719
Other recoveries	(7)
Net reserves (salvage) - financial guaranty	$ 581		$ 571

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

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