XML 24 R8.htm IDEA: XBRL DOCUMENT
v3.25.2

Statement of Financial Position, Unclassified - Insurance Based Operations (Statement) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2025 | Jun. 30, 2024 | Jun. 04, 2024
Disposal Group, Including Discontinued Operation, Net Assets Held-For Sale | $ 6,592,417 |  | $ 6,592,417 |  |
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent | (52,151) | $ 14,182 | (82,398) | $ 38,322 |
Disposal Group, Including Discontinued Operation, Assets | 6,636,855 | 7,099,591 | 6,636,855 | 7,099,591 |
Disposal Group, Including Discontinued Operation, Liabilities | 6,213,024 |  | 6,213,024 |  |
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax | (52,151) | 14,182 | (82,398) | 38,322 |
5.1% Surplus Notes Due 2020 | Ambac Assurance Corporation [Member] |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  |  | 5.10%
Discontinued Operations, Held-for-Sale or Disposed of by Sale | Ambac Assurance Corporation [Member] |  |  |  |  |
Disposal Group, Including Discontinued Operation, Consideration |  |  |  |  | $ 420,000
Disposal Group, Including Discontinued Operation, Consideration, Fair Value, Net, After Allowance For Closing Costs | 394,704 |  | 394,704 |  |
Disposal Group, Including Discontinued Operation, Consideration, Fair Value, Net | 402,239 |  | 402,239 |  |
Disposal Group, Including Discontinued Operation, Estimated Closing Costs | 7,535 |  | 7,535 |  |
Disposal Group, Including Discontinued Operation, Net Assets Held-For Sale | 1,032,305 |  | 1,032,305 |  |
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax |  |  | 637,601 |  |
Disposal Group, Including Discontinued Operation, Valuation Allowance On Assets Held-For-Sale | (637,601) |  | (637,601) |  |
Class of Warrant or Right, Exercise Price of Warrants or Rights |  |  |  |  | $ 18.50
Warrants and Rights Outstanding, Term |  |  |  |  | 6 years 6 months
Class Of Warrant Or Right, Number Of Securities Called By Warrants Or Rights, Percentage Of Fully Diluted Shares Of Common Stock |  |  |  |  | 9.90%
Disposal Group, Including Discontinued Operation, Other Revenue | (8,840) | (15,995) | (16,661) | (21,435) |
Disposal Group, Including Discontinued Operation, Premiums Earned, Net | (5,199) | (5,569) | (9,962) | (13,055) |
Disposal Group, Including Discontinued Operation, Net Investment Income | (36,107) | (32,419) | (56,807) | (70,450) |
Disposal Group, Including Discontinued Operation, Realized Investment Gains (Losses) | 12,514 | 956 | 18,468 | 388 |
Disposal Group, Including Discontinued Operation, Derivative, Gain (Loss) On Derivative, Net | 8,834 | (461) | 9,367 | (1,994) |
Disposal Group, Including Discontinued Operation, Revenue | (28,798) | (53,488) | (55,595) | (106,546) |
Disposal Group, Including Discontinued Operation, Operating Expense | (26,171) | (36,788) | (67,767) | (61,080) |
Disposal Group, Including Discontinued Operation, Operating Income (Loss) | (2,627) | (16,700) | 12,172 | (45,466) |
Discontinued Operation, Tax Effect of Income (Loss) from Discontinued Operation During Phase-out Period | (1,818) | (2,518) | (2,770) | (7,144) |
Disposal Group, Including Discontinued Operation, Policyholder Benefits And Claims Incurred, Net | 2,657 | 5,270 | (8,078) | 25,978 |
Disposal Group, Including Discontinued Operation, Amortization | (5,362) | (7,014) | (11,188) | (18,341) |
Disposal Group, Including Discontinued Operation, General and Administrative Expense | (7,523) | (19,063) | (16,607) | (36,732) |
Disposal Group, Including Discontinued Operation, Interest Expense | (15,943) | (15,986) | (31,894) | (31,966) |
Disposal Group, Including Discontinued Operation, Other Expense | 0 | 5 | 0 | (19) |
Disposal Group, Including Discontinued Operation, Investment | 2,321,619 |  | 2,321,619 |  |
Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents | 13,023 |  | 13,023 |  |
Disposal Group, Including Discontinued Operation, Premiums Receivable, Net | 218,780 |  | 218,780 |  |
Disposal Group, Including Discontinued Operation, Reinsurance Recoverable For Paid And Unpaid Claims And Claims Adjustments | 26,359 |  | 26,359 |  |
Disposal Group, Including Discontinued Operation, Prepaid Reinsurance Premiums | 74,180 |  | 74,180 |  |
Disposal Group, Including Discontinued Operation, Subrogation Recoverable | 110,838 |  | 110,838 |  |
Disposal Group, Including Discontinued Operation, Intangible Assets | 208,424 |  | 208,424 |  |
Disposal Group, Including Discontinued Operation, Other Assets | 71,572 |  | 71,572 |  |
Disposal Group, Including Discontinued Operation, Variable Interest Entity Assets | 4,185,223 |  | 4,185,223 |  |
Disposal Group, Including Discontinued Operation, Assets | 6,592,417 |  | 6,592,417 |  |
Disposal Group, Including Discontinued Operation, Unearned Premiums | 227,968 |  | 227,968 |  |
Disposal Group, Including Discontinued Operation, Liability for Claims and Claims Adjustment Expense | 600,916 |  | 600,916 |  |
Disposal Group, Including Discontinued Operation, Reinsurance Payable | 54,712 |  | 54,712 |  |
Disposal Group, Including Discontinued Operation, Liabilities, Long-Term Debt And Accrued Interest | 1,078,551 |  | 1,078,551 |  |
Disposal Group, Including Discontinued Operation, Other Liabilities | 105,346 |  | 105,346 |  |
Disposal Group, Including Discontinued Operation, Variable Interest Entity Liabilities | 4,145,531 |  | 4,145,531 |  |
Disposal Group, Including Discontinued Operation, Liabilities | 6,213,024 |  | 6,213,024 |  |
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax | $ (52,960) | $ 0 | $ (67,456) | $ 0 |

X
- Definition Class Of Warrant Or Right, Number Of Securities Called By Warrants Or Rights, Percentage Of Fully Diluted Shares Of Common Stock + References No definition available. + Details
Name: | ambc_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRightsPercentageOfFullyDilutedSharesOfCommonStock
Namespace Prefix: | ambc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Amortization + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationAmortization
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Disposal Group, Including Discontinued Operation, Consideration, Fair Value, Net + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationConsiderationFairValueNet
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Consideration, Fair Value, Net, After Allowance For Closing Costs + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationConsiderationFairValueNetAfterAllowanceForClosingCosts
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Derivative, Gain (Loss) On Derivative, Net + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationDerivativeGainLossOnDerivativeNet
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Disposal Group, Including Discontinued Operation, Estimated Closing Costs + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationEstimatedClosingCosts
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Liabilities, Long-Term Debt And Accrued Interest + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationLiabilitiesLongTermDebtAndAccruedInterest
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Net Assets Held-For Sale + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationNetAssetsHeldForSale
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Net Investment Income + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationNetInvestmentIncome
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Disposal Group, Including Discontinued Operation, Other Revenue + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationOtherRevenue
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Disposal Group, Including Discontinued Operation, Policyholder Benefits And Claims Incurred, Net + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationPolicyholderBenefitsAndClaimsIncurredNet
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Disposal Group, Including Discontinued Operation, Premiums Earned, Net + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationPremiumsEarnedNet
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Disposal Group, Including Discontinued Operation, Premiums Receivable, Net + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationPremiumsReceivableNet
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Prepaid Reinsurance Premiums + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationPrepaidReinsurancePremiums
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Realized Investment Gains (Losses) + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationRealizedInvestmentGainsLosses
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Disposal Group, Including Discontinued Operation, Reinsurance Payable + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationReinsurancePayable
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Reinsurance Recoverable For Paid And Unpaid Claims And Claims Adjustments + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationReinsuranceRecoverableForPaidAndUnpaidClaimsAndClaimsAdjustments
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Subrogation Recoverable + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationSubrogationRecoverable
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Unearned Premiums + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationUnearnedPremiums
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Valuation Allowance On Assets Held-For-Sale + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationValuationAllowanceOnAssetsHeldForSale
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Variable Interest Entity Assets + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationVariableInterestEntityAssets
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Disposal Group, Including Discontinued Operation, Variable Interest Entity Liabilities + References No definition available. + Details
Name: | ambc_DisposalGroupIncludingDiscontinuedOperationVariableInterestEntityLiabilities
Namespace Prefix: | ambc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount classified as assets attributable to disposal group held for sale or disposed of. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 10 -SubTopic 20 -Topic 205 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-10 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-7 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5C -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5C Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 360 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482099/360-10-50-3 Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-11 + Details
Name: | us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Exercise price per share or per unit of warrants or rights outstanding. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(h)(4)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-3 + Details
Name: | us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount after tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5C -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5C Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3B Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-1 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3 + Details
Name: | us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount before tax of income (loss) from a discontinued operation. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(12)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3A Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3B Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-4 Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-1 Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3 Reference 8: 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(14)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483621/220-10-S99-2 + Details
Name: | us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount after tax of income (loss) from operations classified as a discontinued operation. Excludes gain (loss) on disposal and provision for gain (loss) until disposal. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3A Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5C -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5C Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3 + Details
Name: | us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of tax expense (benefit) attributable to income (loss) from operations classified as a discontinued operation. Excludes tax expense (benefit) for gain (loss) on disposal and for provision for gain (loss) until disposal. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 740 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482659/740-20-45-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3A Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5C -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5C + Details
Name: | us-gaap_DiscontinuedOperationTaxEffectOfIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount classified as cash and cash equivalents attributable to disposal group held for sale or disposed of. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 10 -SubTopic 20 -Topic 205 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-10 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 360 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482099/360-10-50-3 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-11 + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationCashAndCashEquivalents
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation. + References No definition available. + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of general and administrative expense attributable to disposal group, including, but not limited to, discontinued operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationGeneralAndAdministrativeExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount classified as intangible assets, excluding goodwill, attributable to disposal group held for sale or disposed of. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 10 -SubTopic 20 -Topic 205 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-10 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 360 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482099/360-10-50-3 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-11 + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationIntangibleAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of interest expense attributable to disposal group, including, but not limited to, discontinued operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section S99 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480781/205-20-S99-3 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-6 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-7 + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of investment attributable to disposal group held for sale or disposed of. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 360 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482099/360-10-50-3 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-11 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-10 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of liability for claims and claims adjustment expense attributable to disposal group held for sale or disposed of. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 360 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482099/360-10-50-3 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-11 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-10 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationLiabilityForClaimsAndClaimsAdjustmentExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of operating expense attributable to disposal group, including, but not limited to, discontinued operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount classified as other assets attributable to disposal group held for sale or disposed of. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 10 -SubTopic 20 -Topic 205 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-10 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 360 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482099/360-10-50-3 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-11 + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of other expense attributable to disposal group, including, but not limited to, discontinued operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount classified as other liabilities attributable to disposal group held for sale or disposed of. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 10 -SubTopic 20 -Topic 205 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-10 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 360 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482099/360-10-50-3 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-11 + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of revenue attributable to disposal group, including, but not limited to, discontinued operation. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-7 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount after tax of income (loss) from a discontinued operation attributable to the parent. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 810 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 19 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481231/810-10-45-19 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3A -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3A Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5C -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5C Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3B Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-4 Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-1 Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-3 + Details
Name: | us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount classified as liabilities attributable to disposal group held for sale or disposed of. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 10 -SubTopic 20 -Topic 205 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-10 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 7 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-7 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5C -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5C Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483499/205-20-50-5B Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 360 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482099/360-10-50-3 Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 205 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483475/205-20-45-11 + Details
Name: | us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Period between issuance and expiration of outstanding warrant and right embodying unconditional obligation requiring redemption by transferring asset at specified or determinable date or upon event certain to occur, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -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 (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_WarrantsAndRightsOutstandingTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=ambc_A5.1SurplusNotesDue2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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