Financial Guaranty Insurance Premiums (Details 3) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012
Gross Premium Receivable Net of Ceding Commissions [Roll Forward]
Balance beginning of period	$ 1,005		$ 1,003
Premium written, net of ceding commissions	72		134
Premium payments received, net of ceding commissions	(167)		(225)
Changes in the expected term of financial guaranty insurance contracts	(14)		12
Accretion of discount, net of ceding commissions	15		19
Foreign exchange translation	(7)		10
Consolidation of FG VIEs	0		(5)
Other adjustments	2		(4)
Balance end of period	906	[1]	944	[1]
Gross premium receivable, net of ceding commissions of consolidated FG VIEs	$ 19		$ 30
Percentage of installment premiums denominated in foreign currencies	47.00%		50.00%		47.00%

[1] Excludes $19 million and $30 million as of September 30, 2013 and September 30, 2012, respectively, related to consolidated FG VIEs.