Financial Guaranty Insurance Premiums - Components of Unearned Premium Reserve (Details) - USD ($) $ in Millions		Jun. 30, 2015		Dec. 31, 2014
Financial Guarantee Insurance Premiums [Line Items]
Unearned premium reserve, gross		$ 4,389		$ 4,261
Unearned premium reserve, ceded		282		381
Total net unearned premium reserve related to FG VIE		125		125
Contra-paid related to FG and VIEs		37		42
Consolidated Entity Excluding Consolidation of Variable Interest Entities (VIE) [Member]
Financial Guarantee Insurance Premiums [Line Items]
Deferred premium revenue, gross		4,313		4,167
Deferred premium revenue, ceded		289		387
Deferred premium revenue, net	[1]	4,024		3,780
Contra-paid, gross	[2]	76		94
Contra-paid, ceded	[2]	(7)		(6)
Contra-paid, net	[1],[2]	83		100
Unearned premium reserve, gross		4,389		4,261
Unearned premium reserve, ceded		282		381
Unearned premium reserve, net	[1]	4,107		3,880
Financial Guarantee Insurance Product Line [Member] | Consolidated Entity Excluding Consolidation of Variable Interest Entities (VIE) [Member]
Financial Guarantee Insurance Premiums [Line Items]
Deferred premium revenue, gross		4,312		4,167
Deferred premium revenue, ceded		289		387
Deferred premium revenue, net	[1]	4,023	[3]	3,780
Other Insurance Product Line [Member] | Consolidated Entity Excluding Consolidation of Variable Interest Entities (VIE) [Member]
Financial Guarantee Insurance Premiums [Line Items]
Deferred premium revenue, gross		1		0
Deferred premium revenue, ceded		0		0
Deferred premium revenue, net	[1]	$ 1		$ 0

[1] Excludes $125 million and $125 million of deferred premium revenue, and $37 million and $42 million of contra-paid related to FG VIEs as of June 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 $125 million