XML 93 R72.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Investments (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | $ 475 | $ 568 |
Investment [Line Items] |  |  |
Other Investments | 475 | 568 |
Trading Securities, Realized Gain (Loss) | 18 | (26) | $ 1
Debt Securities, Trading, Unrealized Gain (Loss) | 25 | (48) | 23
Gains (losses) on securities held as of reporting date [Member] |  |  |
Investment [Line Items] |  |  |
Other investments | 7 | (22) | $ 22
Carrying Amount [Member] |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 77 | 61 |
Investment [Line Items] |  |  |
Other Investments | 77 | 61 |
Hedge Funds, Multi-strategy [Member] |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 112 | 186 |
Investment [Line Items] |  |  |
Other Investments | 112 | 186 |
Illiquid Investments [Member] |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 84 | 84 |
Investment [Line Items] |  |  |
Other Investments | 84 | 84 |
Interest Rate Contract [Member] |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 85 | 80 |
Investment [Line Items] |  |  |
Other Investments | 85 | 80 |
Interest Rate Contract [Member] | Carrying Amount [Member] |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 39 | 0 |
Investment [Line Items] |  |  |
Other Investments | 39 | 0 |
Equity [Member] |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 38 | 64 |
Investment [Line Items] |  |  |
Other Investments | 38 | 64 |
Equity [Member] | Carrying Amount [Member] |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 38 | 53 |
Investment [Line Items] |  |  |
Other Investments | 38 | 53 |
Credit Index Product [Member] |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 52 | 63 |
Investment [Line Items] |  |  |
Other Investments | 52 | 63 |
Private Equity Funds, US |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 70 | 47 |
Investment [Line Items] |  |  |
Other Investments | 70 | 47 |
Real Estate [Member] |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 21 | 22 |
Investment [Line Items] |  |  |
Other Investments | 21 | 22 |
Convertibles and Bonds with Warrants Attached |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 0 | 8 |
Investment [Line Items] |  |  |
Other Investments | 0 | 8 |
Convertibles and Bonds with Warrants Attached | Carrying Amount [Member] |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 0 | 8 |
Investment [Line Items] |  |  |
Other Investments | 0 | 8 |
Insurance Linked [Member] |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 1 | 1 |
Investment [Line Items] |  |  |
Other Investments | 1 | 1 |
Equity investments in pooled funds [Member] |  |  |
Investments, Debt and Equity Securities [Abstract] |  |  |
Other Investments | 463 | 556 |
Investment [Line Items] |  |  |
Other Investments | $ 463 | $ 556 |

X
- Definition Other Investments Income + References No definition available. + Details
Name: | ambc_OtherInvestmentsIncome
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in net income (trading). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 14 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-14 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(7)(c)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2 + Details
Name: | us-gaap_DebtSecuritiesTradingRealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in net income (trading). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 14 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-14 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-9 + Details
Name: | us-gaap_DebtSecuritiesTradingUnrealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
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 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 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-12 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 55 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480493/946-210-55-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480990/946-20-50-9 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (g)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (g)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 220 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483580/946-220-50-3 + Details
Name: | us-gaap_SummaryOfInvestmentHoldingsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=ambc_GainslossesonsecuritiesheldasofreportingdateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

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

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

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

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

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

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