Subsidiary Information - Condensed Consolidating Statement of Operations (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016		Mar. 31, 2015
Revenues
Net earned premiums	$ 183	[1]	$ 142
Net investment income	99		101
Net realized investment gains (losses)	(13)		16
Net change in fair value of credit derivatives:
Realized gains (losses) and other settlements	8		21
Net unrealized gains (losses)	(68)		103
Net change in fair value of credit derivatives	(60)		124
Bargain purchase gain and settlement of pre-existing relationships	0
Other	36		(14)
Total revenues	245		369
Expenses
Loss and LAE	90		18
Amortization of DAC	4		4
Interest expense	26		25
Other operating expenses	60		56
Total expenses	180		103
Income (loss) before income taxes	65		266
Total (provision) benefit for income taxes	(6)		(65)
Equity in net earnings of subsidiaries	0		0
Net income (loss)	59		201
Less: noncontrolling interest	0		0
Net income (loss)	59		201
Comprehensive income (loss)	141		201
Reportable Legal Entities [Member] | Assured Guaranty Ltd. (Parent) [Member]
Revenues
Net earned premiums	0		0
Net investment income	0		0
Net realized investment gains (losses)	0		0
Net change in fair value of credit derivatives:
Realized gains (losses) and other settlements	0		0
Net unrealized gains (losses)	0		0
Net change in fair value of credit derivatives	0		0
Bargain purchase gain and settlement of pre-existing relationships	0
Other	0		0
Total revenues	0		0
Expenses
Loss and LAE	0		0
Amortization of DAC	0		0
Interest expense	0		0
Other operating expenses	8		8
Total expenses	8		8
Income (loss) before income taxes	(8)		(8)
Total (provision) benefit for income taxes	0		0
Equity in net earnings of subsidiaries	67		209
Net income (loss)	59		201
Less: noncontrolling interest	0		0
Net income (loss)	59		201
Comprehensive income (loss)	141		201
Reportable Legal Entities [Member] | AGUS (Issuer) [Member]
Revenues
Net earned premiums	0		0
Net investment income	0		0
Net realized investment gains (losses)	0		0
Net change in fair value of credit derivatives:
Realized gains (losses) and other settlements	0		0
Net unrealized gains (losses)	0		0
Net change in fair value of credit derivatives	0		0
Bargain purchase gain and settlement of pre-existing relationships	0
Other	0		0
Total revenues	0		0
Expenses
Loss and LAE	0		0
Amortization of DAC	0		0
Interest expense	13		13
Other operating expenses	0		0
Total expenses	13		13
Income (loss) before income taxes	(13)		(13)
Total (provision) benefit for income taxes	5		5
Equity in net earnings of subsidiaries	50		163
Net income (loss)	42		155
Less: noncontrolling interest	0		0
Net income (loss)	42		155
Comprehensive income (loss)	80		134
Reportable Legal Entities [Member] | AGMH (Issuer) [Member]
Revenues
Net earned premiums	0		0
Net investment income	0		0
Net realized investment gains (losses)	0		0
Net change in fair value of credit derivatives:
Realized gains (losses) and other settlements	0		0
Net unrealized gains (losses)	0		0
Net change in fair value of credit derivatives	0		0
Bargain purchase gain and settlement of pre-existing relationships	0
Other	0		0
Total revenues	0		0
Expenses
Loss and LAE	0		0
Amortization of DAC	0		0
Interest expense	13		13
Other operating expenses	1		0
Total expenses	14		13
Income (loss) before income taxes	(14)		(13)
Total (provision) benefit for income taxes	5		5
Equity in net earnings of subsidiaries	77		92
Net income (loss)	68		84
Less: noncontrolling interest	0		0
Net income (loss)	68		84
Comprehensive income (loss)	92		80
Reportable Legal Entities [Member] | Other Entities [Member]
Revenues
Net earned premiums	192		140
Net investment income	100		104
Net realized investment gains (losses)	(12)		19
Net change in fair value of credit derivatives:
Realized gains (losses) and other settlements	8		21
Net unrealized gains (losses)	(68)		103
Net change in fair value of credit derivatives	(60)		124
Bargain purchase gain and settlement of pre-existing relationships	0
Other	36		(14)
Total revenues	256		373
Expenses
Loss and LAE	93		18
Amortization of DAC	7		6
Interest expense	3		4
Other operating expenses	52		48
Total expenses	155		76
Income (loss) before income taxes	101		297
Total (provision) benefit for income taxes	(16)		(72)
Equity in net earnings of subsidiaries	9		9
Net income (loss)	94		234
Less: noncontrolling interest	9		9
Net income (loss)	85		225
Comprehensive income (loss)	178		233
Consolidating Adjustments [Member]
Revenues
Net earned premiums	(9)		2
Net investment income	(1)		(3)
Net realized investment gains (losses)	(1)		(3)
Net change in fair value of credit derivatives:
Realized gains (losses) and other settlements	0		0
Net unrealized gains (losses)	0		0
Net change in fair value of credit derivatives	0		0
Bargain purchase gain and settlement of pre-existing relationships	0
Other	0		0
Total revenues	(11)		(4)
Expenses
Loss and LAE	(3)		0
Amortization of DAC	(3)		(2)
Interest expense	(3)		(5)
Other operating expenses	(1)		0
Total expenses	(10)		(7)
Income (loss) before income taxes	(1)		3
Total (provision) benefit for income taxes	0		(3)
Equity in net earnings of subsidiaries	(203)		(473)
Net income (loss)	(204)		(473)
Less: noncontrolling interest	(9)		(9)
Net income (loss)	(195)		(464)
Comprehensive income (loss)	$ (350)		$ (447)

[1] Excludes $5 million and $5 million for First Quarter 2016 and 2015, respectively, related to consolidated FG VIEs.