Financial Guaranty Insurance Premiums (Details 3) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013		Jun. 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	32		103
Premium payments received, net of ceding commissions	(109)		(167)
Changes in the expected term of financial guaranty insurance contracts	1		19
Accretion of discount, net of ceding commissions	13		13
Foreign exchange translation	(27)		(1)
Consolidation of FG VIEs	0		(5)
Other adjustments	0		(1)
Balance end of period	915	[1]	964	[1]
Gross premium receivable, net of ceding commissions of consolidated FG VIEs	$ 20		$ 32
Percentage of installment premiums denominated in foreign currencies	46.00%		49.00%		47.00%

[1] Excludes $20 million and $32 million as of June 30, 2013 and June 30, 2012, respectively, related to consolidated FG VIEs.