Document and Entity Information	3 Months Ended
	Mar. 31, 2011	Nov. 04, 2011
Document and Entity Information
Entity Registrant Name	ASSURED GUARANTY LTD
Entity Central Index Key	0001273813
Document Type	10-Q
Document Period End Date	Mar. 31, 2011
Amendment Flag	true
Amendment Description	This Amendment No. 1 on Form 10-Q/A ("Form 10-Q/A") amends our quarterly report on Form 10-Q for the quarter ended March 31, 2011, which was originally filed on May 10, 2011 ("Original Form 10-Q"). This amendment is being filed to include restated financial statements as described in Note 2 to the consolidated financial statements contained in "Item 1. Financial Statements," financial data and related disclosures. The Company is restating its previously issued consolidated financial statements as of and for the quarters ended March 31, 2011 and 2010 to reflect the Company's determination that it did not properly account for the elimination of intercompany activity between the Company's insurance subsidiaries and its consolidated financial guaranty variable interest entities. Included in this restatement is the correction of other immaterial errors which affected the quarters ended March 31, 2011 and 2010. The total effect of this restatement was a decrease to equity of $50.4 million and $65.3 million as of March 31, 2011 and December 31, 2010, respectively, and increases to net income of $15.2 million and $11.5 million for the quarters ended March 31, 2011 and 2010, respectively. As a result of the errors discussed above, management has now determined that the Company had a material weakness in its internal control over financial reporting at March 31, 2011. A material weakness is a deficiency, or combination of control deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of the annual or interim financial statements will not be prevented or detected on a timely basis. For a discussion of management's consideration of the Company's disclosure controls and procedures and the material weakness identified, see Part I, Item 4, Controls and Procedures of this Form 10-Q/A. In accordance with the rules of the Securities and Exchange Commission (the "SEC"), this Form 10-Q/A sets forth the complete text of the following items of the Original Form 10-Q as modified where necessary to reflect the restatement: Part I - Item 1. Financial Statements; Part I - Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations; Part I - Item 4. Controls and Procedures; and Part II - Item 6. Exhibits. In accordance with rules of the SEC, this Form 10-Q/A also includes as exhibits certifications from our Chief Executive Officer and Chief Financial Officer dated as of the date of this filing. Except for the items noted above, no other information included in the Original Form 10-Q is being amended by this Form 10-Q/A. This Form 10-Q/A continues to speak as of the date of the Original Form 10-Q and we have not updated the filing to reflect events occurring subsequently to the Original Form 10-Q date other than those associated with the restatement of the Company's financial statements and certain material events which are identified as to date. Accordingly, this Form 10-Q/A should be read in conjunction with the Company's filings with the SEC subsequent to the filing of the Original 10-Q, including any amendments to those filings.
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		182,228,965
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q1