Financial Guaranty Insurance Losses - Loss and LAE Reserve and Salvage and Subrogation Recoverable Net of Reinsurance Insurance Contracts (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	$ 689		$ 659
Subtotal, Salvage and Subrogation Recoverable, net	236		240
Subtotal, Net	453		419
Effect of consolidating FG VIEs, Loss and LAE Reserve, net	(90)		(103)
Effect of consolidating FG VIEs, Salvage and Subrogation Recoverable, net	(17)		(85)
Effect of consolidating FG VIEs, Net	(73)		(18)
Total, Loss and LAE Reserve, net	599	[1]	556	[1]
Total, Salvage and subrogation recoverable payable, net	219	[1]	155	[1]
Total, Net	380	[1]	401	[1]
Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	688		657
Subtotal, Salvage and Subrogation Recoverable, net	231		235
Subtotal, Net	457		422
Total, Net	367		389
Other
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	1		2
Subtotal, Salvage and Subrogation Recoverable, net	5		5
Subtotal, Net	(4)		(3)
Prime first lien | Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	3		3
Subtotal, Salvage and Subrogation Recoverable, net	0		0
Subtotal, Net	3		3
Alt-A first lien | Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	112		108
Subtotal, Salvage and Subrogation Recoverable, net	0		0
Subtotal, Net	112		108
Option ARM | Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	19		22
Subtotal, Salvage and Subrogation Recoverable, net	57		47
Subtotal, Net	(38)		(25)
First mortgage, subprime | Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	135		143
Subtotal, Salvage and Subrogation Recoverable, net	1		2
Subtotal, Net	134		141
Total first lien | Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	269		276
Subtotal, Salvage and Subrogation Recoverable, net	58		49
Subtotal, Net	211		227
Close ended second lien | Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	5		5
Subtotal, Salvage and Subrogation Recoverable, net	43		45
Subtotal, Net	(38)		(40)
HELOCs | Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	6		5
Subtotal, Salvage and Subrogation Recoverable, net	117		127
Subtotal, Net	(111)		(122)
Second lien | Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	11		10
Subtotal, Salvage and Subrogation Recoverable, net	160		172
Subtotal, Net	(149)		(162)
U.S. RMBS | Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	280		286
Subtotal, Salvage and Subrogation Recoverable, net	218		221
Subtotal, Net	62		65
TruPS | Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	1		2
Subtotal, Salvage and Subrogation Recoverable, net	0		0
Subtotal, Net	1		2
Structured finance | Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	159		145
Subtotal, Salvage and Subrogation Recoverable, net	5		6
Subtotal, Net	154		139
Public Finance U.S. | Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	212		189
Subtotal, Salvage and Subrogation Recoverable, net	8		8
Subtotal, Net	204		181
Public Finance Non-U.S. | Financial guaranty insurance
Guarantor Obligations [Line Items]
Subtotal, Loss and LAE Reserve, net	36		35
Subtotal, Salvage and Subrogation Recoverable, net	0		0
Subtotal, Net	$ 36		$ 35

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