Consolidated Variable Interest Entities - Consolidated FG VIE's By Type of Collateral (Details) - USD ($) $ in Millions	Dec. 31, 2015		Dec. 31, 2014
Variable Interest Entity [Line Items]
Financial guaranty variable interest entities' assets with recourse, at fair value	$ 1,131	[1]	$ 1,239
Financial guaranty variable interest entities’ liabilities with recourse, at fair value	1,225	[1]	1,277
Financial guaranty variable interest entities' assets without recourse, at fair value	130	[1]	163
Financial guaranty variable interest entities’ liabilities without recourse, at fair value	124	[1]	142
Financial guaranty variable interest entities’ assets, at fair value	1,261	[1]	1,402
Financial guaranty variable interest entities’ liabilities, at fair value	1,349	[1]	1,419
Other Insurance Product Line [Member]
Variable Interest Entity [Line Items]
Financial guaranty variable interest entities' assets with recourse, at fair value	431	[1]	369
Financial guaranty variable interest entities’ liabilities with recourse, at fair value	431	[1]	369
United States [Member] | First Lien [Member] | Residential Mortgage-Backed Securities (RMBS) [Member]
Variable Interest Entity [Line Items]
Financial guaranty variable interest entities' assets with recourse, at fair value	506	[1]	632
Financial guaranty variable interest entities’ liabilities with recourse, at fair value	521	[1]	581
United States [Member] | Second Lien [Member] | Residential Mortgage-Backed Securities (RMBS) [Member]
Variable Interest Entity [Line Items]
Financial guaranty variable interest entities' assets with recourse, at fair value	194	[1]	238
Financial guaranty variable interest entities’ liabilities with recourse, at fair value	273	[1]	$ 327
Radian [Member]
Variable Interest Entity [Line Items]
Financial guaranty variable interest entities’ assets, at fair value	111
Financial guaranty variable interest entities’ liabilities, at fair value	$ 107

[1] The December 31, 2015 amounts include $111 million of FG VIE assets and $107 million of FG VIE liabilities acquired from Radian Asset.