Consolidated Variable Interest Entities - Consolidated FG VIE's By Type of Collateral (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Financial guaranty variable interest entities' assets with recourse, at fair value	$ 647	$ 725
Financial guaranty variable interest entities’ liabilities with recourse, at fair value	721	807
Financial guaranty variable interest entities' assets without recourse, at fair value	134	151
Financial guaranty variable interest entities’ liabilities without recourse, at fair value	134	151
Financial guaranty variable interest entities’ assets, at fair value	781	876
Financial guaranty variable interest entities’ liabilities, at fair value	855	958
Manufactured Housing Loans [Member]
Variable Interest Entity [Line Items]
Financial guaranty variable interest entities' assets with recourse, at fair value	73	74
Financial guaranty variable interest entities’ liabilities with recourse, at fair value	74	75
United States [Member] | First Lien [Member] | RMBS [Member]
Variable Interest Entity [Line Items]
Financial guaranty variable interest entities' assets with recourse, at fair value	406	473
Financial guaranty variable interest entities’ liabilities with recourse, at fair value	436	509
United States [Member] | Second Lien [Member] | RMBS [Member]
Variable Interest Entity [Line Items]
Financial guaranty variable interest entities' assets with recourse, at fair value	168	178
Financial guaranty variable interest entities’ liabilities with recourse, at fair value	$ 211	$ 223