XML 79 R57.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Business and Basis of Presentation - Gain on Equity Method Investment (Details) - USD ($) $ in Millions |  | 12 Months Ended
--- | --- | ---
Jul. 01, 2023 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Schedule of Equity Method Investments [Line Items] |  |  |  |
Investments, fair value | $ 450 |  |  |
Gain on sale of asset management subsidiaries | 262 | $ 262 | $ 0 | $ 0
Goodwill and other intangible assets |  | 6 | $ 163 |
Sound Point Agreement |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Goodwill and other intangible assets | 155 |  |  |
Sound Point |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Investments, fair value | 425 | 631 |  |
Gain on sale of asset management subsidiaries | 255 |  |  |
Nonconsolidated Investees, Other |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Investments, fair value | 25 |  |  |
Cash | 13 |  |  |
Receivables, Fair Value Disclosure | 12 |  |  |
Assured IM |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Equity method investments | 188 |  |  |
Goodwill and other intangible assets |  | $ 0 |  |
Assured Healthcare Partners LLC |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |
Gain on sale of asset management subsidiaries | $ 7 |  |  |

X
- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. + References No definition available. + Details
Name: | us-gaap_CashAndCashEquivalentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of gain (loss) on sale or disposal of an equity method investment. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-28 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(b)(7)(c)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(b)(9)(a)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2 + Details
Name: | us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481664/323-10-45-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481687/323-10-50-3 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(10)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 25 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482810/280-10-50-25 + Details
Name: | us-gaap_EquityMethodInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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 Amount of gain (loss) on sale or disposal of equity in securities of subsidiaries or equity method investee. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-28 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(b)(7)(c)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(b)(9)(a)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(3)(a)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(13)(g)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1 + Details
Name: | us-gaap_GainLossOnSaleOfStockInSubsidiaryOrEquityMethodInvestee
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Carrying amount of finite-lived intangible assets, indefinite-lived intangible assets and goodwill. Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Intangible assets are assets, not including financial assets, lacking physical substance. + References No definition available. + Details
Name: | us-gaap_IntangibleAssetsNetIncludingGoodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of receivables, including, but not limited to, trade account receivables, note receivables, and loan receivables. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-10 Reference 2: 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(7)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1 + Details
Name: | us-gaap_ReceivablesFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(g)(1)(ii)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481687/323-10-50-3 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 28 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-28 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481687/323-10-50-3 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481687/323-10-50-3 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481687/323-10-50-3 + Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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

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

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