Financial Guaranty Insurance - Selected Information for Policies Paid In Installments (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Jun. 30, 2016		Dec. 31, 2015	Jun. 30, 2015	[1]	Dec. 31, 2014
Financial Guarantee Insurance Premiums [Line Items]
Premiums receivable, net of commission payable	$ 623	[1]	$ 693	$ 702		$ 729
Financial Guarantee Policies Paid in Installments [Member]
Financial Guarantee Insurance Premiums [Line Items]
Premiums receivable, net of commission payable	623		693
Gross deferred premium revenue	$ 1,086		$ 1,240
Weighted-average risk-free rate used to discount premiums	3.10%		3.10%
Weighted-average period of premiums receivable (in years)	9 years 2 months 4 days		9 years 4 months 24 days

[1] Excludes $11 million and $23 million as of June 30, 2016 and June 30, 2015, respectively, related to consolidated FG VIEs. Excludes $1 million related to non-financial guaranty line of business as of June 30, 2015