Financial Guaranty Insurance - Net Earned Premiums (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Financial Guarantee Insurance Premiums [Line Items]
Scheduled net earned premiums		$ 93	$ 118	$ 184	$ 214
Acceleration of net earned premiums	[1]	117	96	206	137
Accretion of discount on net premiums receivable		4	5	7	9
Financial guaranty insurance net earned premiums		214	219	397	360
Other		0	0	0	1
Net	[2]	214	219	397	361
Variable Interest Entity, Primary Beneficiary [Member]
Financial Guarantee Insurance Premiums [Line Items]
Net		$ 5	$ 3	$ 8	$ 10

[1] Reflects the unscheduled refunding or termination of the insurance on an insured obligation as well as changes in scheduled earnings due to changes in the expected lives of the insured obligations.

[2] Excludes $3 million and $5 million for Second Quarter 2016 and 2015, respectively, and $8 million and $10 million for Six Months 2016 and 2015, respectively, related to consolidated FG VIEs.