Reinsurance and Other Monoline Exposures (Details 2) (USD $)						1 Months Ended				1 Months Ended
	Mar. 31, 2012	Mar. 31, 2012 AGM and AGC	Mar. 31, 2012 National Public Finance Guarantee Corporation	Mar. 31, 2012 American Overseas Reinsurance Company Limited	Mar. 31, 2012 Tokio Marine & Nichido Fire Insurance Co., Ltd.	Feb. 29, 2012 Tokio Marine & Nichido Fire Insurance Co., Ltd. Public finance	Jan. 31, 2012 Radian Asset Assurance Inc.	Mar. 31, 2012 Radian Asset Assurance Inc.	Jan. 24, 2012 Radian Asset Assurance Inc.	Jan. 31, 2012 Radian Asset Assurance Inc. Public finance	Jan. 31, 2012 Radian Asset Assurance Inc. Structured Finance	Mar. 31, 2012 Syncora Guarantee Inc.	Mar. 31, 2012 Mitsui Sumitomo Insurance Co. Ltd.	Mar. 31, 2012 ACA Financial Guaranty Corp.	Mar. 31, 2012 Swiss Reinsurance Co.	Mar. 31, 2012 Ambac	Mar. 31, 2012 CIFG Assurance North America Inc.	Mar. 31, 2012 MBIA Inc.	Mar. 31, 2012 Financial Guaranty Insurance Co.	Mar. 31, 2012 Other.
Exposure, Premium Receivable, and Loss and LAE by Reinsurer
Fixed maturity securities wrapped by monoline reinsurer			$ 772,200,000													$ 550,200,000				$ 49,800,000
Ceded Par Outstanding	35,435,000,000			11,146,000,000	9,444,000,000			5,591,000,000				4,304,000,000	2,388,000,000	860,000,000	506,000,000	87,000,000	65,000,000	25,000,000		1,019,000,000
Second-to-Pay Insured Par Outstanding	27,411,000,000							45,000,000				2,174,000,000		7,000,000		7,488,000,000	258,000,000	11,598,000,000	3,789,000,000	2,052,000,000
Assumed Par Outstanding	43,463,000,000			24,000,000	936,000,000			1,768,000,000				213,000,000		2,000,000		22,330,000,000	6,246,000,000	9,719,000,000	2,129,000,000	96,000,000
Ceded par outstanding related to insured credit derivatives	4,646,000,000
Assumed Premium Receivable, net of Commissions	108,400,000															97,200,000	200,000	200,000	10,800,000
Ceded Premium Payable, net of Commissions	(150,200,000)			(12,500,000)	(26,300,000)			(19,400,000)				(39,000,000)	(4,700,000)		(3,500,000)				(6,800,000)	(38,000,000)
Assumed Expected Loss and LAE	(151,900,000)											2,000,000				(91,900,000)	(100,000)	(12,600,000)	(49,300,000)
Ceded Expected Loss and LAE	182,700,000			24,700,000	83,800,000			25,900,000				600,000	25,100,000		20,400,000		2,200,000
Minimum net losses required for attachment of excess of loss reinsurance facility		2,000,000,000
Amount of losses covered under the facility		600,000,000
Amount of losses which the reinsurers will assume on pro rata basis		435,000,000
Remaining amount of losses covered under the facility		165,000,000
Amount agreed to be reassumed						6,200,000,000	12,900,000,000
Approximate amount of insurance risk agreed to be assumed										1,800,000,000
Payment receivable for re-assumption of ceded risk									86,000,000
Percentage of obligations insured										96.00%	4.00%
Incremental present value from future installment premiums									1,900,000
Payment receivable in connection with reinsurance									22,000,000
Premiums paid during the period	21,800,000
Remaining insurance premium payable	$ 21,800,000