XML 120 R98.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Investments and Cash - Narrative (Details) $ in Millions |  | 12 Months Ended
--- | --- | ---
Jul. 01, 2023 USD ($) | Dec. 31, 2023 USD ($) Security fund manager | Dec. 31, 2022 USD ($) Security | Dec. 31, 2021 USD ($)
Schedule of Cost-method Investments [Line Items] |  |  |  |
Number of investment portfolio managers | manager |  | 3 |  |
Accounted for as consolidated investment vehicles | fund |  | 3 |  |
Total number of investments | fund |  | 8 |  |
Investments, fair value | $ 450 |  |  |
Accrued investment income |  | $ 71 | $ 71 |
Number of securities with unrealized losses greater than 10% of book value for 12 months or more | Security |  | 409 | 567 |
Total unrealized losses for securities having losses greater than 10% of book value for 12 months or more |  | $ 200 | $ 329 |
Assets held-in-trust |  | 234 | 222 |
Non-income producing investments |  | 0 | 0 |
Purchased with credit deterioration, amount at purchase price |  |  | 22 |
Securities purchased with credit deterioration, amount at par value |  |  | 31 |
Allowance for credit loss at acquisition date |  |  | 2 |
Discount attributable to other factors |  |  | 7 |
Other invested assets (includes $3 and $30, at fair value) |  | 829 | 133 |
Indefinite-lived intangible assets |  | 6 | 6 |
Finite-lived intangible assets |  | 0 | 40 |
Nonconsolidated Investees, Other |  |  |  |
Schedule of Cost-method Investments [Line Items] |  |  |  |
Investments, fair value | 25 |  |  |
Sound Point |  |  |  |
Schedule of Cost-method Investments [Line Items] |  |  |  |
Investments, fair value | $ 425 | 631 |  |
Useful life | 6 years 4 months 24 days |  |  |
Disposal Group, Held-for-Sale, Not Discontinued Operations | Sound Point Agreement |  |  |  |
Schedule of Cost-method Investments [Line Items] |  |  |  |
Investment management commitment | $ 1,000 | 1,000 |  |
Assured Guaranty Subsidiaries |  |  |  |
Schedule of Cost-method Investments [Line Items] |  |  |  |
Assets held-in-trust |  | 1,154 | 1,169 |
AssuredIM Funds | Equity in Earnings (Losses) of Investees | Assured Guaranty Asset Strategies LLC |  |  |  |
Schedule of Cost-method Investments [Line Items] |  |  |  |
Fair value of investment |  | 571 |  |
Equity Securities |  |  |  |
Schedule of Cost-method Investments [Line Items] |  |  |  |
Cash dividends from subsidiaries |  | 7 | 10 | $ 15
Alternative Investment | Equity in Earnings (Losses) of Investees | Assured Guaranty Asset Strategies LLC |  |  |  |
Schedule of Cost-method Investments [Line Items] |  |  |  |
Long-term purchase commitment, amount |  | 775 |  |
Investments, funded amount |  | 534 |  |
Alternative Investment | Future Equity Investments |  |  |  |
Schedule of Cost-method Investments [Line Items] |  |  |  |
Authorized amount to invest |  | 1,500 |  |
Fair value of investment |  | 739 |  |
Unfunded committment |  | 779 |  |
Committed for specific funds |  | 363 |  |
Investments, including distributed gains, authorized amount to invest |  | 108 |  |
Alternative Investment | Future Equity Investments | Assured Guaranty Subsidiaries |  |  |  |
Schedule of Cost-method Investments [Line Items] |  |  |  |
Authorized amount to invest |  | 858 |  |
Authorized amount to invest, excluding distributed gains |  | 750 |  |
Sound Point |  |  |  |
Schedule of Cost-method Investments [Line Items] |  |  |  |
Other invested assets (includes $3 and $30, at fair value) |  | 429 | $ 0 |
Indefinite-lived intangible assets |  | 243 |  |
Finite-lived intangible assets |  | $ 37 |  |

X
- Definition Represents the number of securities which had unrealized losses greater than 10% of book value for 12 months or more. + References No definition available. + Details
Name: | ago_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionGreaterThan10PercentOfBookValueTwelveMonthsOrLongerNumber
Namespace Prefix: | ago_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition This item represents the excess of amortized cost basis over fair value of securities that have been in a loss position for twelve months or longer for those securities which are categorized neither as held-to-maturity nor trading securities and which have unrealized losses greater than 10% of book value. + References No definition available. + Details
Name: | ago_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerGreaterThan10PercentBookValueAggregateLosses
Namespace Prefix: | ago_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Discontinued Operation, Continuing Involvement, Investment Management Commitment + References No definition available. + Details
Name: | ago_DiscontinuedOperationContinuingInvolvementInvestmentManagementCommitment
Namespace Prefix: | ago_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Investment, Non-income Producing, Value + References No definition available. + Details
Name: | ago_InvestmentNonIncomeProducingValue
Namespace Prefix: | ago_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Investments, Accounted For As Consolidated Investment Vehicles + References No definition available. + Details
Name: | ago_InvestmentsAccountedForAsConsolidatedInvestmentVehicles
Namespace Prefix: | ago_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Investments, Authorized Amount To Invest + References No definition available. + Details
Name: | ago_InvestmentsAuthorizedAmountToInvest
Namespace Prefix: | ago_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Investments, Authorized Amount To Invest, Excluding Distributed Gains + References No definition available. + Details
Name: | ago_InvestmentsAuthorizedAmountToInvestExcludingDistributedGains
Namespace Prefix: | ago_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Investments, Funded Amount + References No definition available. + Details
Name: | ago_InvestmentsFundedAmount
Namespace Prefix: | ago_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Investments, Including Distributed Gains, Authorized Amount To Invest + References No definition available. + Details
Name: | ago_InvestmentsIncludingDistributedGainsAuthorizedAmountToInvest
Namespace Prefix: | ago_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Investments, Unfunded Committment + References No definition available. + Details
Name: | ago_InvestmentsUnfundedCommittment
Namespace Prefix: | ago_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Investments, Unfunded Committment, Committed For Specific Funds + References No definition available. + Details
Name: | ago_InvestmentsUnfundedCommittmentCommittedForSpecificFunds
Namespace Prefix: | ago_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of Outside Managers Managing Investment Portfolio + References No definition available. + Details
Name: | ago_NumberofOutsideManagersManagingInvestmentPortfolio
Namespace Prefix: | ago_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total Number of Investments + References No definition available. + Details
Name: | ago_TotalNumberOfInvestments
Namespace Prefix: | ago_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(4)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(3)(a)(4)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(10)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1 + Details
Name: | us-gaap_AccruedInvestmentIncomeReceivable
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The total amount of cash and securities held by third party trustees pursuant to terms of debt instruments or other agreements as of the date of each statement of financial position presented, which can be used by the trustee only to pay the noncurrent portion of specified obligations. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(b)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1 + Details
Name: | us-gaap_AssetsHeldInTrust
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, excluding accrued interest, of allowance for credit loss at acquisition date of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) purchased with credit deterioration. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479106/326-30-50-10 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479106/326-30-50-9 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterestPurchasedWithCreditDeteriorationAllowanceForCreditLossAtAcquisitionDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount at par value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), purchased with credit deterioration. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479106/326-30-50-10 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSalePurchasedWithCreditDeteriorationAmountAtParValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount at purchase price of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), purchased with credit deterioration. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479106/326-30-50-10 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSalePurchasedWithCreditDeteriorationAmountAtPurchasePrice
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of discount (premium) attributable to other factors on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), purchased with credit deterioration. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479106/326-30-50-10 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSalePurchasedWithCreditDeteriorationDiscountPremium
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair value portion of investments accounted under the equity method. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2E -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2E Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (h) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(12)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_EquityMethodInvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 926 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483154/926-20-50-5 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 350 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482665/350-30-50-2 + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 350 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482665/350-30-50-2 + Details
Name: | us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The minimum amount the entity agreed to spend under the long-term purchase commitment. + References No definition available. + Details
Name: | us-gaap_LongTermPurchaseCommitmentAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of investments classified as other. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(12)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_OtherInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Dividends received on equity and other investments during the current period. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 16 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-16 + Details
Name: | us-gaap_ProceedsFromDividendsReceived
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- 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. + References No definition available. + Details
Name: | us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=us-gaap_OtherInvesteesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=ago_SoundPointCapitalManagementLPMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=ago_SoundPointAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=ago_AssuredGuarantySubsidiariesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=ago_AssuredInvestmentManagementFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis=us-gaap_EquityMethodInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=ago_AssuredGuarantyAssetStrategiesLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=ago_AlternativeInvestmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis=ago_FutureEquityInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=ago_SoundPointCapitalManagementLPMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |