Reinsurance and Other Monoline Exposures (Details 2) (USD $)																											1 Months Ended			1 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Minimum	Dec. 31, 2011 AGM and AGC	Dec. 31, 2011 Public finance	Dec. 31, 2010 Public finance	Dec. 31, 2011 Structured Finance	Dec. 31, 2010 Structured Finance	Dec. 31, 2011 Super senior	Dec. 31, 2011 Super senior Structured Finance	Dec. 31, 2011 AAA	Dec. 31, 2011 AAA Public finance	Dec. 31, 2011 AAA Structured Finance	Dec. 31, 2011 AA	Dec. 31, 2011 AA Public finance	Dec. 31, 2011 AA Structured Finance	Dec. 31, 2011 A	Dec. 31, 2011 A Public finance	Dec. 31, 2011 A Structured Finance	Dec. 31, 2011 BBB	Dec. 31, 2011 BBB Public finance	Dec. 31, 2011 BBB Structured Finance	Dec. 31, 2011 BIG	Dec. 31, 2011 BIG Public finance	Dec. 31, 2011 BIG Structured Finance	Dec. 31, 2011 National Public Finance Guarantee Corporation	Jan. 31, 2012 Radian Asset Assurance Inc.	Jan. 24, 2012 Radian Asset Assurance Inc.	Dec. 31, 2011 Radian Asset Assurance Inc.	Jan. 31, 2012 Radian Asset Assurance Inc. Public finance	Jan. 31, 2012 Radian Asset Assurance Inc. Structured Finance	Dec. 31, 2011 Radian Asset Assurance Inc. Super senior	Dec. 31, 2011 Radian Asset Assurance Inc. AAA	Dec. 31, 2011 Radian Asset Assurance Inc. AAA Structured Finance	Dec. 31, 2011 Radian Asset Assurance Inc. AA	Dec. 31, 2011 Radian Asset Assurance Inc. A	Dec. 31, 2011 Radian Asset Assurance Inc. A Public finance	Dec. 31, 2011 Radian Asset Assurance Inc. BBB	Dec. 31, 2011 Radian Asset Assurance Inc. BBB Public finance	Dec. 31, 2011 Radian Asset Assurance Inc. BIG	Dec. 31, 2011 Radian Asset Assurance Inc. BIG Public finance	Dec. 31, 2011 Tokio Marine & Nichido Fire Insurance Co., Ltd.	Dec. 31, 2011 Tokio Marine & Nichido Fire Insurance Co., Ltd. Super senior	Dec. 31, 2011 Tokio Marine & Nichido Fire Insurance Co., Ltd. AAA	Dec. 31, 2011 Tokio Marine & Nichido Fire Insurance Co., Ltd. AA	Dec. 31, 2011 Tokio Marine & Nichido Fire Insurance Co., Ltd. A	Dec. 31, 2011 Tokio Marine & Nichido Fire Insurance Co., Ltd. BBB	Dec. 31, 2011 Tokio Marine & Nichido Fire Insurance Co., Ltd. BIG	Dec. 31, 2011 American Overseas Reinsurance Company Limited	Dec. 31, 2011 American Overseas Reinsurance Company Limited Super senior	Dec. 31, 2011 American Overseas Reinsurance Company Limited AAA	Dec. 31, 2011 American Overseas Reinsurance Company Limited AA	Dec. 31, 2011 American Overseas Reinsurance Company Limited A	Dec. 31, 2011 American Overseas Reinsurance Company Limited BBB	Dec. 31, 2011 American Overseas Reinsurance Company Limited BIG	Dec. 31, 2011 Syncora Guarantee Inc.	Dec. 31, 2011 Syncora Guarantee Inc. AAA Structured Finance	Dec. 31, 2011 Syncora Guarantee Inc. AA	Dec. 31, 2011 Syncora Guarantee Inc. AA Public finance	Dec. 31, 2011 Syncora Guarantee Inc. AA Structured Finance	Dec. 31, 2011 Syncora Guarantee Inc. A	Dec. 31, 2011 Syncora Guarantee Inc. A Public finance	Dec. 31, 2011 Syncora Guarantee Inc. A Structured Finance	Dec. 31, 2011 Syncora Guarantee Inc. BBB	Dec. 31, 2011 Syncora Guarantee Inc. BBB Public finance	Dec. 31, 2011 Syncora Guarantee Inc. BBB Structured Finance	Dec. 31, 2011 Syncora Guarantee Inc. BIG	Dec. 31, 2011 Syncora Guarantee Inc. BIG Public finance	Dec. 31, 2011 Syncora Guarantee Inc. BIG Structured Finance	Dec. 31, 2011 Mitsui Sumitomo Insurance Co. Ltd.	Dec. 31, 2011 Mitsui Sumitomo Insurance Co. Ltd. Super senior	Dec. 31, 2011 Mitsui Sumitomo Insurance Co. Ltd. AAA	Dec. 31, 2011 Mitsui Sumitomo Insurance Co. Ltd. AA	Dec. 31, 2011 Mitsui Sumitomo Insurance Co. Ltd. A	Dec. 31, 2011 Mitsui Sumitomo Insurance Co. Ltd. BBB	Dec. 31, 2011 Mitsui Sumitomo Insurance Co. Ltd. BIG	Dec. 31, 2011 ACA Financial Guaranty Corp.	Dec. 31, 2011 ACA Financial Guaranty Corp. AA	Dec. 31, 2011 ACA Financial Guaranty Corp. AA Public finance	Dec. 31, 2011 ACA Financial Guaranty Corp. A	Dec. 31, 2011 ACA Financial Guaranty Corp. BBB	Dec. 31, 2011 ACA Financial Guaranty Corp. BBB Public finance	Dec. 31, 2011 Swiss Reinsurance Co.	Dec. 31, 2011 Swiss Reinsurance Co. AAA	Dec. 31, 2011 Swiss Reinsurance Co. AA	Dec. 31, 2011 Swiss Reinsurance Co. A	Dec. 31, 2011 Swiss Reinsurance Co. BBB	Dec. 31, 2011 Swiss Reinsurance Co. BIG	Dec. 31, 2011 Ambac	Dec. 31, 2011 Ambac AAA Structured Finance	Dec. 31, 2011 Ambac AA Public finance	Dec. 31, 2011 Ambac AA Structured Finance	Dec. 31, 2011 Ambac A	Dec. 31, 2011 Ambac A Public finance	Dec. 31, 2011 Ambac A Structured Finance	Dec. 31, 2011 Ambac BBB Public finance	Dec. 31, 2011 Ambac BBB Structured Finance	Dec. 31, 2011 Ambac BIG Public finance	Dec. 31, 2011 Ambac BIG Structured Finance	Dec. 31, 2011 CIFG Assurance North America Inc.	Dec. 31, 2011 CIFG Assurance North America Inc. AA Public finance	Dec. 31, 2011 CIFG Assurance North America Inc. A Public finance	Dec. 31, 2011 CIFG Assurance North America Inc. BBB Public finance	Dec. 31, 2011 CIFG Assurance North America Inc. BIG	Dec. 31, 2011 CIFG Assurance North America Inc. BIG Public finance	Dec. 31, 2011 MBIA Inc.	Dec. 31, 2011 MBIA Inc. AAA Public finance	Dec. 31, 2011 MBIA Inc. AA	Dec. 31, 2011 MBIA Inc. AA Public finance	Dec. 31, 2011 MBIA Inc. AA Structured Finance	Dec. 31, 2011 MBIA Inc. A Public finance	Dec. 31, 2011 MBIA Inc. A Structured Finance	Dec. 31, 2011 MBIA Inc. BBB Public finance	Dec. 31, 2011 MBIA Inc. BBB Structured Finance	Dec. 31, 2011 MBIA Inc. BIG Public finance	Dec. 31, 2011 MBIA Inc. BIG Structured Finance	Dec. 31, 2011 Financial Guaranty Insurance Co.	Dec. 31, 2011 Financial Guaranty Insurance Co. Super senior Structured Finance	Dec. 31, 2011 Financial Guaranty Insurance Co. AAA Structured Finance	Dec. 31, 2011 Financial Guaranty Insurance Co. AA Public finance	Dec. 31, 2011 Financial Guaranty Insurance Co. A Public finance	Dec. 31, 2011 Financial Guaranty Insurance Co. A Structured Finance	Dec. 31, 2011 Financial Guaranty Insurance Co. BBB Public finance	Dec. 31, 2011 Financial Guaranty Insurance Co. BBB Structured Finance	Dec. 31, 2011 Financial Guaranty Insurance Co. BIG Public finance	Dec. 31, 2011 Financial Guaranty Insurance Co. BIG Structured Finance	Dec. 31, 2011 Other.	Dec. 31, 2011 Other. AA	Dec. 31, 2011 Other. A	Dec. 31, 2011 Other. A Public finance	Dec. 31, 2011 Other. BBB
Exposure, Premium Receivable, and Loss and LAE by Reinsurer
Fixed maturity securities wrapped by monoline reinsurer																										$ 770,300,000																																																															$ 568,800,000																																						$ 49,200,000
Ceded Par Outstanding	56,294,000,000	64,117,000,000			48,146,000,000	53,727,000,000	8,148,000,000	10,390,000,000	727,000,000		4,269,000,000			17,956,000,000			20,538,000,000			10,170,000,000			2,634,000,000						19,310,000,000			93,000,000	892,000,000		7,490,000,000	7,805,000,000		2,627,000,000		403,000,000		16,345,000,000	361,000,000	1,540,000,000	4,673,000,000	6,037,000,000	2,941,000,000	793,000,000	11,444,000,000	265,000,000	1,657,000,000	4,049,000,000	3,262,000,000	1,642,000,000	569,000,000	4,222,000,000		287,000,000			962,000,000			2,330,000,000			643,000,000			2,407,000,000	8,000,000	171,000,000	825,000,000	917,000,000	404,000,000	82,000,000	855,000,000	483,000,000		329,000,000	43,000,000		505,000,000	9,000,000	3,000,000	320,000,000	98,000,000	75,000,000	87,000,000				87,000,000							69,000,000				69,000,000		27,000,000		27,000,000																			1,023,000,000	119,000,000	819,000,000		85,000,000
Second-to-Pay Insured Par Outstanding	27,380,000,000									476,000,000		66,000,000	1,033,000,000		4,992,000,000	1,592,000,000		11,765,000,000	576,000,000		4,494,000,000	644,000,000		1,085,000,000	657,000,000				50,000,000					1,000,000			13,000,000		22,000,000		14,000,000															2,171,000,000	205,000,000		25,000,000	134,000,000		384,000,000	12,000,000		749,000,000	93,000,000		328,000,000	241,000,000								12,000,000		8,000,000			4,000,000							7,491,000,000	99,000,000	1,741,000,000	69,000,000		3,453,000,000	256,000,000	1,123,000,000	83,000,000	335,000,000	332,000,000	258,000,000	11,000,000	69,000,000	133,000,000		45,000,000	11,549,000,000	66,000,000		3,053,000,000	1,389,000,000	4,603,000,000	54,000,000	1,893,000,000	460,000,000	8,000,000	23,000,000	3,857,000,000	476,000,000	728,000,000	154,000,000	1,251,000,000	254,000,000	570,000,000	8,000,000	355,000,000	61,000,000	1,992,000,000			1,992,000,000
Assumed Par Outstanding	43,074,000,000																																									934,000,000							24,000,000							217,000,000																					2,000,000												22,680,000,000											6,561,000,000						10,422,000,000											2,138,000,000										96,000,000
Ceded par outstanding related to insured credit derivatives	5,438,000,000
Total collateral posted by all non-affiliated reinsurers			1,000,000,000
Assumed Premium Receivable, net of Commissions	117,000,000																																																																																								97,900,000											6,800,000						800,000											11,500,000
Assumed Expected Loss and LAE	(138,000,000)																																																							(2,600,000)																																	(99,900,000)											(100,000)						(13,100,000)											(22,300,000)
Ceded Expected Loss and LAE	123,000,000																												12,900,000													75,100,000							19,700,000							200,000														9,900,000													3,800,000																	1,400,000
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 of par agreed to be reassumed which was previously ceded																											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