Financial Guaranty Insurance Premiums - Components of Unearned Premium Reserve (Details) - USD ($) $ in Millions		Sep. 30, 2015		Dec. 31, 2014
Financial Guarantee Insurance Premiums [Line Items]
Deferred premium revenue, gross		$ 4,126		$ 4,167
Deferred premium revenue, ceded		271		387
Deferred premium revenue, net	[1]	3,855		3,780
Contra-paid, gross	[2]	(14)		94
Contra-paid, ceded	[2]	(8)		(6)
Contra-paid, net	[1],[2]	(6)		100
Unearned premium reserve, gross		4,112		4,261
Unearned premium reserve, ceded		263		381
Unearned premium reserve, net	[1]	3,849		3,880
Total net unearned premium reserve related to FG VIE		120		125
Contra-paid related to FG and VIEs		35		42
Financial Guarantee Insurance Product Line [Member]
Financial Guarantee Insurance Premiums [Line Items]
Deferred premium revenue, gross		4,126		4,167
Deferred premium revenue, ceded		271		387
Deferred premium revenue, net	[1]	3,855	[3]	3,780
Other Insurance Product Line [Member]
Financial Guarantee Insurance Premiums [Line Items]
Deferred premium revenue, gross		0		0
Deferred premium revenue, ceded		0		0
Deferred premium revenue, net	[1]	$ 0		$ 0

[1] Excludes $120 million and $125 million of deferred premium revenue, and $35 million and $42 million of contra-paid related to FG VIEs as of September 30, 2015 and December 31, 2014, respectively.

[2] See Note 7, "Financial Guaranty Insurance Losses– Insurance Contracts' Loss Information" for an explanation of "contra-paid".

[3] Excludes scheduled net earned premiums on consolidated FG VIEs of $120 million