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Represents the amount of payment on the termination of credit derivatives transactions which the complainant owes to defendant as per the calculation of defendant.

No definition available.

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Represents the number of credit derivative transactions for which the entity has improperly calculated the termination payment as per the allegations of the complainants.

No definition available.

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Represents the number of credit derivative transactions which the entity has improperly terminated as per the allegations of the plaintiff.

No definition available.

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Represents the number of credit derivative transactions which the entity has improperly terminated as per the allegations of the complainants.

No definition available.

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Loss Contingency, Number of Claims, Motion to Dismiss Denied

No definition available.

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Loss Contingency, Number of Claims, Remaining After Dismissals

No definition available.

Name:	ago_LossContingencyNumberofClaimsRemainingAfterDismissals
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Operating Leases, Canceled Term Of Existing Leases

No definition available.

Name:	ago_OperatingLeasesCanceledTermOfExistingLeases
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Balance Type:	na
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Operating Leases, Future Estimated Rent Expense, Net

No definition available.

Name:	ago_OperatingLeasesFutureEstimatedRentExpenseNet
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Balance Type:	debit
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Operating Leases, Number Of Step Increases In Operating Lease Expense

No definition available.

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Operating Leases, Rent Expense After Step Increases, Net

No definition available.

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Operating Leases, Rent Expense After Step Increases, Term

No definition available.

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Operating Leases, Rented Area

No definition available.

Name:	ago_OperatingLeasesRentedArea
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The amount or range of possible amounts of gain that could be realized upon the resolution of a contingency.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6397426&loc=d3e17499-108355

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Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

No definition available.

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Period Type:	duration

Term of the lessee's leasing arrangement renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm
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Data Type:	xbrli:durationItemType
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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.

No definition available.

Name:	us-gaap_LossContingenciesLineItems
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Data Type:	xbrli:stringItemType
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Number of claims dismissed.

No definition available.

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

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The total number of new claims filed pertaining to a loss contingency during the period.

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Data Type:	xbrli:integerItemType
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Number of plaintiffs that have filed claims pertaining to a loss contingency.

No definition available.

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Data Type:	xbrli:integerItemType
Balance Type:	na
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The estimated maximum amount of possible loss from the contingency.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
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-Section 50
-Paragraph 9
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-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349

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The estimated minimum amount of possible loss from the contingency.

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Data Type:	xbrli:monetaryItemType
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Name:	dei_LegalEntityAxis=ago_AssuredGuarantyFinancialProductsIncMember
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Name:	dei_LegalEntityAxis=ago_AssuredGuarantyMunicipalCorpandAssuredGuarantyMunicipalHoldingsIncMember
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