Consolidated Statement of Shareholders' Equity (USD $) In Millions, except Share data, unless otherwise specified	Total	Total Shareholders' Equity Attributable to Assured Guaranty Ltd.	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income	Deferred Equity Compensation
Balance at Dec. 31, 2010	$ 3,670		$ 2	$ 2,586	$ 968	$ 112	$ 2
Balance (in shares) at Dec. 31, 2010			183,744,655
Increase (Decrease) in Shareholders' Equity
Net income (loss)	773				773
Dividends (2011 $0.18, 2012 $0.36, 2013 $0.40 per share)	(33)				(33)
Common stock repurchases (in shares)			(2,000,000)
Common stock repurchases	(23.0)		0	(23.0)
Share-based compensation and other (in shares)			491,143
Share-based compensation and other	9		0	7			2
Other comprehensive income (loss)	256					256
Balance at Dec. 31, 2011	4,652		2	2,570	1,708	368	4
Balance (in shares) at Dec. 31, 2011			182,235,798
Increase (Decrease) in Shareholders' Equity
Net income (loss)	110	110			110
Dividends (2011 $0.18, 2012 $0.36, 2013 $0.40 per share)		(69)			(69)
Common stock issuance, net (in shares)			13,428,770
Common stock issuance, net		173	0	173
Common stock repurchases (in shares)			(2,066,759)
Common stock repurchases		(24.0)	0	(24.0)
Share-based compensation and other (in shares)			405,488
Share-based compensation and other		5	0	5			0
Other comprehensive income (loss)	147	147				147
Balance at Dec. 31, 2012	4,994		2	2,724	1,749	515	4
Balance (in shares) at Dec. 31, 2012			194,003,297
Increase (Decrease) in Shareholders' Equity
Net income (loss)	808				808
Dividends (2011 $0.18, 2012 $0.36, 2013 $0.40 per share)	(75)				(75)
Common stock repurchases (in shares)			(12,512,759)
Common stock repurchases	(264.0)		0	(264.0)
Share-based compensation and other (in shares)			687,328
Share-based compensation and other	7		0	6			1
Other comprehensive income (loss)	(355)					(355)
Balance at Dec. 31, 2013	$ 5,115		$ 2	$ 2,466	$ 2,482	$ 160	$ 5
Balance (in shares) at Dec. 31, 2013			182,177,866