Financial Guaranty Insurance Premiums - Net Earned Premiums (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Financial Guarantee Insurance Premiums [Line Items]
Scheduled net earned premiums		$ 104	$ 105	$ 318	$ 318
Acceleration of net earned premiums		105	36	242	79
Accretion of discount on net premiums receivable		4	3	13	14
Financial guaranty insurance net earned premiums		213	144	573	411
Other		0	0	1	1
Net	[1]	213	144	574	412
Variable Interest Entity, Primary Beneficiary [Member]
Financial Guarantee Insurance Premiums [Line Items]
Net		$ 6	$ 5	$ 16	$ 27

[1] Excludes $6 million and $5 million for Third Quarter 2015 and 2014, respectively, and $16 million and $27 million for Nine Months 2015 and 2014, respectively, related to consolidated financial guaranty ("FG") VIEs.