Municipal Bond Guarantee (Details) (USD $) In Millions, unless otherwise specified		3 Months Ended	12 Months Ended	1 Months Ended	3 Months Ended				3 Months Ended			1 Months Ended	3 Months Ended			3 Months Ended
	Mar. 31, 2014	Mar. 31, 2014 BAM Contract	Dec. 31, 2013 BAM Contract	Jul. 31, 2012 HG Global	Mar. 31, 2014 HG Global	Mar. 31, 2013 HG Global	Mar. 31, 2014 HG Global Preferred Stock [Member]	Mar. 31, 2014 HG Global Common Stock	Mar. 31, 2014 Build America Mutual	Mar. 31, 2013 Build America Mutual	Mar. 31, 2014 HG Re [Member]	Jul. 31, 2012 BAM Management	Mar. 31, 2014 Surplus Note [Member] BAM	Mar. 31, 2014 Fixed interest rate [Member] Surplus Note [Member] BAM	Mar. 31, 2014 Variable Rate [Domain] Surplus Note [Member] BAM	Mar. 31, 2014 Combination One Surplus Note [Member] BAM	Mar. 31, 2014 Combination Two Surplus Note [Member] BAM
Guarantor Obligations [Line Items]
basis points													3.00%
Municipal bond contract		907	701
Insured Financial Obligations, Remaining Weighted Average Contract Period		13 years 7 months 10 days	13 years 9 months 21 days
Municipal bond outstanding principal		$ 6,015.0	$ 4,703.7
Municipal bond outstanding interest		4,140.9	3,264.4
Municipal bond debt service outstanding		10,155.9	7,968.1
Partners Capital Contribution				594.5								14.5
Ownership interest (as a percent)							96.90%	88.40%
Surplus Notes				503.0	503.0
Statutory Accounting Practices, Statutory Capital and Surplus, Balance											439.9
Percentage of par value of policy reinsured	15.00%				15.00%
Income (Loss) from Continuing Operations before Income Taxes, Domestic					4.6	9.9			(8.6)	(18.4)
Interest income (expense), surplus notes					3.9	10.1			(3.9)	(10.1)
Number of years of change in interest rate																5	3
Financial Guarantee Insurance Contracts, Unearned Premium Revenue		$ 17.7	$ 13.2
Debt Instrument, Interest Rate, Stated Percentage														8.00%	3.13%
Year of U.S. Treasury Rate			1