Financial Guaranty Insurance Premiums - Components of Unearned Premium Reserve (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Financial Guaranty Insurance Premiums [Line Items]
Deferred premium revenue, gross	$ 4,572		$ 4,652
Deferred premium revenue, ceded	472		470
Deferred premium revenue, net	4,100	[1]	4,182	[1]
Unearned premium reserve	4,504		4,595
Prepaid Reinsurance Premiums	454		452
Unearned Premiums, Net	4,050	[1]	4,143	[1]
Total net unearned premium reserve related to FG VIE	137		187
Contra-paid related to FG and VIEs	49		55
Financial guaranty insurance
Financial Guaranty Insurance Premiums [Line Items]
Deferred premium revenue, gross	4,567		4,647
Deferred premium revenue, ceded	472		470
Deferred premium revenue, net	4,095	[1]	4,177	[1]
Contra-paid, gross	(68)		(57)
Contra-paid, ceded	(18)		(18)
Contra-paid, net	(50)	[1]	(39)	[1]
Other
Financial Guaranty Insurance Premiums [Line Items]
Unearned premium reserve	5		5
Prepaid Reinsurance Premiums	0		0
Unearned Premiums, Net	$ 5	[1]	$ 5	[1]

[1] Excludes $137 million and $187 million of deferred premium revenue, and $49 million and $55 million of contra-paid related to FG VIEs as of March 31, 2014 and December 31, 2013, respectively.