Subsidiary Information (Details 2) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Revenues
Net earned premiums	$ 230,068,000	$ 292,110,000	$ 484,045,000	$ 611,670,000	$ 1,186,700,000	$ 930,400,000	$ 261,400,000
Net investment income	100,827,000	90,871,000	197,214,000	175,173,000	354,700,000	259,200,000	162,600,000
Net realized investment gains (losses)	(5,090,000)	(8,438,000)	(2,284,000)	975,000	(2,000,000)	(32,700,000)	(69,800,000)
Net change in fair value of credit derivatives:
Realized gains and other settlements	(10,836,000)	38,353,000	24,591,000	65,056,000	153,500,000	163,600,000	117,600,000
Net unrealized gains (losses)	(48,625,000)	35,115,000	(319,751,000)	287,213,000	(157,800,000)	(337,800,000)	38,000,000
Net change in fair value of credit derivatives	(59,461,000)	73,468,000	(295,160,000)	352,269,000	(4,300,000)	(174,200,000)	155,600,000
Other income	(164,300,000)	(400,000)	(27,700,000)	(25,200,000)	(133,800,000)	(65,600,000)	43,400,000
Total Revenues	102,012,000	447,685,000	356,065,000	1,114,967,000	1,401,300,000	917,100,000	553,200,000
Expenses
Loss and LAE	132,908,000	71,156,000	105,861,000	201,657,000	413,800,000	377,800,000	265,800,000
Amortization of deferred acquisition costs	9,533,000	6,936,000	16,953,000	15,109,000	34,100,000	53,900,000	61,200,000
Interest expense	24,696,000	24,831,000	49,456,000	49,965,000	99,600,000	62,800,000	23,300,000
Goodwill and settlement of pre-existing relationship						23,300,000
Other operating expenses	48,500,000	50,200,000	105,300,000	116,800,000	218,300,000	266,400,000	90,600,000
Total expenses	215,645,000	153,181,000	277,613,000	383,543,000	765,800,000	784,200,000	440,900,000
Income (loss) before income taxes	(113,633,000)	294,504,000	78,452,000	731,424,000	635,500,000	132,900,000	112,300,000
Total provision (benefit) for income taxes	(55,966,000)	90,966,000	10,712,000	205,911,000	86,600,000	36,900,000	43,400,000
Net income (loss)	(57,667,000)	203,538,000	67,740,000	525,513,000	548,900,000	96,000,000	68,900,000
Less: Noncontrolling interest of variable interest entities						(1,200,000)
Net income (loss)	(57,700,000)	203,500,000	67,700,000	525,500,000	548,900,000	97,200,000	68,900,000
Total Shareholders' Equity Attributable to Assured Guaranty Ltd.
Revenues
Net investment income						100,000	500,000
Net change in fair value of credit derivatives:
Equity in earnings of subsidiaries	(52,300,000)	207,000,000	81,500,000	539,600,000	573,300,000	124,500,000	85,600,000
Total Revenues	(52,300,000)	207,000,000	81,500,000	539,600,000	573,300,000	124,600,000	86,100,000
Expenses
Other operating expenses	5,400,000	3,500,000	13,800,000	14,100,000	24,400,000	27,400,000	17,200,000
Total expenses	5,400,000	3,500,000	13,800,000	14,100,000	24,400,000	27,400,000	17,200,000
Income (loss) before income taxes	(57,700,000)	203,500,000	67,700,000	525,500,000	548,900,000	97,200,000	68,900,000
Net income (loss)	(57,700,000)	203,500,000	67,700,000	525,500,000	548,900,000	97,200,000	68,900,000
Net income (loss)	(57,700,000)	203,500,000	67,700,000	525,500,000	548,900,000	97,200,000	68,900,000
AGUS (Issuer)
Revenues
Net investment income						500,000	100,000
Net change in fair value of credit derivatives:
Equity in earnings of subsidiaries	(60,800,000)	201,500,000	100,900,000	449,000,000	511,300,000	319,400,000	136,100,000
Other income							1,000,000
Total Revenues	(60,800,000)	201,500,000	100,900,000	449,000,000	511,300,000	319,900,000	137,200,000
Expenses
Interest expense	9,900,000	9,800,000	19,700,000	19,600,000	39,300,000	31,600,000	23,300,000
Other operating expenses	100,000	2,700,000	300,000	2,800,000	3,300,000	18,800,000
Total expenses	10,000,000	12,500,000	20,000,000	22,400,000	42,600,000	50,400,000	23,300,000
Income (loss) before income taxes	(70,800,000)	189,000,000	80,900,000	426,600,000	468,700,000	269,500,000	113,900,000
Total provision (benefit) for income taxes	(3,500,000)	(4,300,000)	(7,000,000)	(7,800,000)	(14,900,000)	(15,800,000)	(7,800,000)
Net income (loss)	(67,300,000)	193,300,000	87,900,000	434,400,000	483,600,000	285,300,000	121,700,000
Net income (loss)	(67,300,000)	193,300,000	87,900,000	434,400,000	483,600,000	285,300,000	121,700,000
AGMH (Issuer)
Revenues
Net investment income	100,000	100,000	300,000	200,000	500,000	300,000
Net realized investment gains (losses)					100,000
Net change in fair value of credit derivatives:
Equity in earnings of subsidiaries	29,100,000	177,300,000	307,200,000	303,800,000	585,300,000	743,600,000
Total Revenues	29,200,000	177,400,000	307,500,000	304,000,000	585,900,000	743,900,000
Expenses
Interest expense	13,400,000	13,400,000	26,800,000	26,800,000	53,600,000	26,800,000
Other operating expenses	200,000	600,000	700,000	1,200,000	2,800,000	2,500,000
Total expenses	13,600,000	14,000,000	27,500,000	28,000,000	56,400,000	29,300,000
Income (loss) before income taxes	15,600,000	163,400,000	280,000,000	276,000,000	529,500,000	714,600,000
Total provision (benefit) for income taxes	(4,700,000)	(4,800,000)	(9,500,000)	(9,600,000)	(21,100,000)	(10,100,000)
Net income (loss)	20,300,000	168,200,000	289,500,000	285,600,000	550,600,000	724,700,000
Net income (loss)	20,300,000	168,200,000	289,500,000	285,600,000	550,600,000	724,700,000
Other Subsidiaries
Revenues
Net earned premiums	227,500,000	288,000,000	478,900,000	602,000,000	1,168,200,000	895,200,000	261,400,000
Net investment income	104,400,000	94,600,000	204,400,000	182,500,000	369,200,000	259,400,000	162,000,000
Net realized investment gains (losses)	(5,100,000)	(9,800,000)	(2,300,000)	(3,100,000)	(6,100,000)	(32,900,000)	(69,800,000)
Net change in fair value of credit derivatives:
Realized gains and other settlements	(10,800,000)	38,400,000	24,600,000	65,100,000	153,500,000	163,600,000	117,600,000
Net unrealized gains (losses)	(48,600,000)	35,100,000	(319,700,000)	287,200,000	(157,800,000)	(337,800,000)	38,000,000
Net change in fair value of credit derivatives	(59,400,000)	73,500,000	(295,100,000)	352,300,000	(4,300,000)	(174,200,000)	155,600,000
Equity in earnings of subsidiaries	(67,300,000)	193,300,000	87,900,000	434,400,000	483,600,000	285,300,000
Other income	(163,900,000)	(100,000)	(26,200,000)	(25,100,000)	(132,700,000)	(52,900,000)	43,400,000
Total Revenues	36,200,000	639,500,000	447,600,000	1,543,000,000	1,877,900,000	1,179,900,000	552,600,000
Expenses
Loss and LAE	131,000,000	67,500,000	102,700,000	200,500,000	408,900,000	378,300,000	265,800,000
Amortization of deferred acquisition costs	13,400,000	9,000,000	28,200,000	19,900,000	41,700,000	18,100,000	61,200,000
Interest expense	5,200,000	5,500,000	10,500,000	11,100,000	21,700,000	4,900,000
Goodwill and settlement of pre-existing relationship						(147,100,000)
Other operating expenses	43,100,000	43,900,000	92,200,000	99,300,000	190,000,000	255,300,000	73,400,000
Total expenses	192,700,000	125,900,000	233,600,000	330,800,000	662,300,000	509,500,000	400,400,000
Income (loss) before income taxes	(156,500,000)	513,600,000	214,000,000	1,212,200,000	1,215,600,000	670,400,000	152,200,000
Total provision (benefit) for income taxes	(48,600,000)	94,600,000	23,600,000	212,800,000	110,300,000	56,500,000	51,200,000
Net income (loss)	(107,900,000)	419,000,000	190,400,000	999,400,000	1,105,300,000	613,900,000	101,000,000
Less: Noncontrolling interest of variable interest entities						(1,200,000)
Net income (loss)	(107,900,000)	419,000,000	190,400,000	999,400,000	1,105,300,000	615,100,000	101,000,000
Consolidating Adjustments
Revenues
Net earned premiums	2,500,000	4,100,000	5,100,000	9,700,000	18,500,000	35,200,000
Net investment income	(3,700,000)	(3,800,000)	(7,500,000)	(7,500,000)	(15,000,000)	(1,100,000)
Net realized investment gains (losses)		1,400,000		4,100,000	4,000,000	200,000
Net change in fair value of credit derivatives:
Equity in earnings of subsidiaries	151,300,000	(779,100,000)	(577,500,000)	(1,726,800,000)	(2,153,500,000)	(1,472,800,000)	(221,700,000)
Other income	(400,000)	(300,000)	(1,500,000)	(100,000)	(1,100,000)	(12,700,000)	(1,000,000)
Total Revenues	149,700,000	(777,700,000)	(581,400,000)	(1,720,600,000)	(2,147,100,000)	(1,451,200,000)	(222,700,000)
Expenses
Loss and LAE	1,900,000	3,700,000	3,200,000	1,200,000	4,900,000	(500,000)
Amortization of deferred acquisition costs	(3,900,000)	(2,100,000)	(11,300,000)	(4,800,000)	(7,600,000)	35,800,000
Interest expense	(3,800,000)	(3,800,000)	(7,500,000)	(7,500,000)	(15,000,000)	(500,000)
Goodwill and settlement of pre-existing relationship						170,400,000
Other operating expenses	(300,000)	(500,000)	(1,700,000)	(600,000)	(2,200,000)	(37,600,000)
Total expenses	(6,100,000)	(2,700,000)	(17,300,000)	(11,700,000)	(19,900,000)	167,600,000
Income (loss) before income taxes	155,800,000	(775,000,000)	(564,100,000)	(1,708,900,000)	(2,127,200,000)	(1,618,800,000)	(222,700,000)
Total provision (benefit) for income taxes	900,000	5,500,000	3,700,000	10,500,000	12,300,000	6,300,000
Net income (loss)	154,900,000	(780,500,000)	(567,800,000)	(1,719,400,000)	(2,139,500,000)	(1,625,100,000)	(222,700,000)
Net income (loss)	$ 154,900,000	$ (780,500,000)	$ (567,800,000)	$ (1,719,400,000)	$ (2,139,500,000)	$ (1,625,100,000)	$ (222,700,000)