XML 100 R73.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Expected Loss to be Paid (Recovered) - Net Expected Loss to be Paid (Recovered) and Net Economic Loss Development (Benefit) by Accounting Model (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net Expected Loss to be Paid (Recovered) | $ 106 | $ 505 | $ 522 | $ 411
Net Economic Loss Development (Benefit) | (3) | 164 | (125) |
Insurance (see Note 5) |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net Expected Loss to be Paid (Recovered) | 90 | 263 |  |
Net Economic Loss Development (Benefit) | (1) | 174 | (112) |
FG VIEs (see Note 8) |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net Expected Loss to be Paid (Recovered) | 16 | 240 |  |
Net Economic Loss Development (Benefit) | (1) | (11) | (17) |
Credit derivatives (see Note 6) |  |  |  |
Schedule of Expected Losses to be Paid [Line Items] |  |  |  |
Net Expected Loss to be Paid (Recovered) | 0 | 2 |  |
Net Economic Loss Development (Benefit) | $ (1) | $ 1 | $ 4 |

X
- Definition Guarantor Obligations, Net Expected Loss Development After Recoveries for Representations and Warranties + References No definition available. + Details
Name: | ago_GuarantorObligationsNetExpectedLossDevelopmentAfterRecoveriesforRepresentationsandWarranties
Namespace Prefix: | ago_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Guarantor Obligations, Net Expected Loss to be Paid After Recoveries for Representations and Warranties + References No definition available. + Details
Name: | ago_GuarantorObligationsNetExpectedLosstobePaidAfterRecoveriesforRepresentationsandWarranties
Namespace Prefix: | ago_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition [Line Items] for Schedule of Expected Losses to be Paid [Table] + References No definition available. + Details
Name: | ago_ScheduleofExpectedLossestobePaidLineItems
Namespace Prefix: | ago_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_GuaranteeObligationsByNatureAxis=ago_InsuranceContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GuaranteeObligationsByNatureAxis=ago_FinancialGuaranteeVariableInterestEntitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_GuaranteeObligationsByNatureAxis=ago_FinancialGuaranteeAccountedforasCreditDerivativesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |