Financial Guaranty Insurance Premiums - Gross Premium Receivable, Net of Commissions on Assumed Business Roll Forward (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Dec. 31, 2013
Gross Premium Receivable Net of Ceding Commissions [Roll Forward]
Beginning of period, December 31	$ 876		$ 1,005
Gross premium written, net of commissions on assumed business	116		72
Gross premiums received, net of commissions on assumed business	(172)		(167)
Changes in the expected term	(21)		(14)
Accretion of discount, net of commissions on assumed business	17		15
Foreign exchange translation	(16)		(7)
Other adjustments	1		2
Balance end of period	801	[1]	906	[1]
Gross premium receivable, net of ceding commissions of consolidated FG VIEs	$ 18		$ 19
Percentage of installment premiums denominated in foreign currencies	49.00%				48.00%

[1] Excludes $18 million and $19 million as of September 30, 2014 and September 30, 2013, respectively, related to consolidated FG VIEs.