Consolidated Statements of Operations (USD $) In Thousands, except Per Share data	3 Months Ended
	Mar. 31, 2011	Mar. 31, 2010
Revenues
Net earned premiums	$ 253,977	$ 314,620
Net investment income	96,061	84,302
Net realized investment gains (losses):
Other-than-temporary impairment losses	(6,947)	(1,117)
Less: portion of other-than-temporary impairment loss recognized in other comprehensive income	(2,369)	(661)
Other net realized investment gains (losses)	7,384	9,869
Net realized investment gains (losses)	2,806	9,413
Net change in fair value of credit derivatives:
Realized gains and other settlements	35,427	26,703
Net unrealized gains (losses)	(271,636)	252,098
Net change in fair value of credit derivatives	(236,209)	278,801
Fair value gain (loss) on committed capital securities	526	(1,275)
Net change in financial guaranty variable interest entities	119,601	(8,913)
Other income	42,151	(12,929)
Total Revenues	278,913	664,019
Expenses
Loss and loss adjustment expenses	(25,580)	110,852
Amortization of deferred acquisition costs	7,420	8,173
Assured Guaranty Municipal Holdings Inc. acquisition-related expenses		4,021
Interest expense	24,760	25,134
Other operating expenses	56,835	62,533
Total expenses	63,435	210,713
Income (loss) before income taxes	215,478	453,306
Provision (benefit) for income taxes
Current	(197,599)	(38,953)
Deferred	272,465	158,799
Total provision (benefit) for income taxes	74,866	119,846
Net income (loss)	$ 140,612	$ 333,460
Earnings per share:
Basic (in dollars per share)	$ 0.76	$ 1.81
Diluted (in dollars per share)	$ 0.75	$ 1.75
Dividends per share (in dollars per share)	$ 0.045	$ 0.045