Financial Guaranty Contracts Accounted for as Insurance (Details 2) (USD $)	3 Months Ended
	Jun. 30, 2011	Dec. 31, 2010	Dec. 31, 2009
Gross
Total	$ 6,315,362,000	$ 6,972,894,000	$ 8,400,200,000
Ceded
Total	773,321,000	821,819,000	1,080,500,000
Net
Total	5,542,100,000	6,151,100,000
Net unearned premium reserve related to VIE	306,700,000	193,200,000
Net
Reduction in future scheduled amortization of deferred premium revenue due to consolidating FG VIEs	444,500,000
Reduction in net present value of expected loss due to consolidating FG VIEs	260,300,000
Financial Guaranty
Gross
Deferred premium revenue	6,412,600,000	7,108,600,000
Contra-paid	(106,700,000)	(146,100,000)
Total	6,305,900,000	6,962,500,000
Ceded
Deferred premium revenue	791,100,000	846,600,000
Contra-paid	(18,100,000)	(24,800,000)
Total	773,000,000	821,800,000
Net
Deferred premium revenue	5,621,500,000	6,262,000,000
Contra-paid	(88,600,000)	(121,300,000)
Total	5,532,900,000	6,140,700,000
Scheduled Net Earned Premium
2011 (July 1 - September 30)	180,100,000
2011 (October 1 - December 31)	167,800,000
2012	574,700,000
2013	480,500,000
2014	424,100,000
2015	374,900,000
2016 - 2020	1,408,300,000
2021 - 2025	886,000,000
2026 - 2030	543,200,000
After 2030	581,900,000
Total present value basis	5,621,500,000
Discount	341,400,000
Total future value	5,962,900,000
Net Expected Loss to be Expensed
2011 (July 1 - September 30)	51,100,000
2011 (October 1 - December 31)	40,400,000
2012	109,200,000
2013	64,500,000
2014	47,300,000
2015	37,600,000
2016 - 2020	121,500,000
2021 - 2025	65,900,000
2026 - 2030	33,200,000
After 2030	18,400,000
Total present value basis	589,100,000	831,300,000
Discount	442,100,000
Total future value	1,031,200,000
Net
2011 (July 1 - September 30)	129,000,000
2011 (October 1 - December 31)	127,400,000
2012	465,500,000
2013	416,000,000
2014	376,800,000
2015	337,300,000
2016 - 2020	1,286,800,000
2021 - 2025	820,100,000
2026 - 2030	510,000,000
After 2030	563,500,000
Total present value basis	5,032,400,000
Discount	(100,700,000)
Total future value	4,931,700,000
Other
Gross
Total	9,500,000	10,400,000
Ceded
Total	300,000
Net
Total	$ 9,200,000	$ 10,400,000