Represents the number of plaintiffs who filed a consolidated putative class action lawsuit no longer naming the entity as defendant but describing some of the entity's activities.

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- Definition

Represents the amount of the underlying obligation insured by financial guarantors including the entity, which is the subject matter of a putative class action.

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- Definition

Represents the minimum number of proceedings for recoveries of losses, or failure to obtain recoveries, to have a material impact on the entity's results of operations in a particular quarter or fiscal year.

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- Definition

Represents the number of non-class action lawsuits for which the entity requested dismissal and the dismissal was denied by the court.

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- Definition

Represents number of commutations disputed.

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- Definition

Represents the number of non-class action lawsuits filed naming the entity among other defendants.

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- Definition

Represents the number of putative class action lawsuits that were filed in a federal court alleging federal antitrust violations in the municipal derivatives industry.

+ Details

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- Definition

Represents the percentage of amount in segregated account payable in cash.

+ Details

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Period Type:	duration

- Definition

Represents the percentage of amount in segregated account payable in surplus notes issued.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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Commitments and Contingencies (Details) (USD $)	12 Months Ended	1 Months Ended			9 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended	1 Months Ended		12 Months Ended	9 Months Ended
Commitments and Contingencies (Details) (USD $)	Dec. 31, 2008 lawsuit	Aug. 31, 2008 AGM Litigation Alabama	Mar. 31, 2011 AGM Litigation New York	Mar. 29, 2011 AGM Litigation New York	Sep. 30, 2011 AG Re and AGC Litigation Wisconsin commutation	Dec. 31, 2008 AGM and AGMH lawsuit	Sep. 30, 2009 AGMH (Issuer)	Dec. 31, 2008 AGMH (Issuer) lawsuit	May 31, 2010 AGM and AGUS lawsuit	Apr. 30, 2010 AGM and AGUS lawsuit	Dec. 31, 2009 AGM and AGUS lawsuit	Sep. 30, 2011 Legal Proceedings lawsuit
Commitments and Contingencies Legal Proceedings
Minimum number of proceedings for recovery effort outcomes to have potential material impact												1
Amount of sewer debt obligation related to putative class action		$ 3,200,000,000
Amount to be repaid to the MARM 2006-OA2 trust as per court order			7,200,000
Estimated unreimbursed claims				$ 144,000,000
Percentage of amount in segregated account payable in cash (as a percent)					25.00%
Percentage of amount in segregated account payable in surplus notes issued (as a percent)					75.00%
Number of commutations disputed					1
Number of putative class action lawsuits filed in federal court	9					5		4
Number of plaintiffs filing consolidated complaints							4
Number of non-class action lawsuits filed						5			5		6
Number of non-class action lawsuits for which dismissal was denied										11