$AMBC
AMBAC FINANCIAL GROUP INC Stock $ambc

$ambc Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-Q Financial Statement

#000087450120000131 Filed on November 09, 2020

Income Statement

Concept	2020 Q4	2020 Q3	2019 Q3
Revenue	$53.00M	$62.00M	$216.0M
YoY Change	26.19%	-71.3%	61.18%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin			$2.300M
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$17.00M	$14.00M	$17.50M
YoY Change	15.65%	-20.0%	-33.96%
% of Gross Profit
Operating Expenses	$50.00M	$121.0M	$80.20M
YoY Change	-63.34%	50.87%	-9.17%
Operating Profit
YoY Change
Interest Expense	-$42.00M	-$53.00M	-$66.90M
YoY Change	-37.03%	-20.78%	1.83%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	-$12.00M	-$108.0M	$60.00M
YoY Change	-89.19%	-280.0%	-250.63%
Income Tax	$2.000M	$0.00	$3.000M
% Of Pretax Income			5.0%
Net Earnings	-$14.00M	-$108.0M	$66.00M
YoY Change	-87.27%	-263.64%	-163.46%
Net Earnings / Revenue	-26.42%	-174.19%	30.56%
Basic Earnings Per Share	-$0.31	-$2.33	$1.44
Diluted Earnings Per Share	-$0.31	-$2.33	$1.41
COMMON SHARES
Basic Shares Outstanding	45.81M shares	46.18M shares	46.00M shares
Diluted Shares Outstanding		46.18M shares	47.02M shares

Balance Sheet

Concept	2020 Q4	2020 Q3	2019 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$20.00M	$37.00M	$52.00M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets
YoY Change
LONG-TERM ASSETS
Property, Plant & Equipment	$25.00M		$26.00M
YoY Change	0.0%
Goodwill	$46.00M
YoY Change
Intangibles	$409.0M	$383.0M	$433.5M
YoY Change	-4.22%	-11.65%
Long-Term Investments	$51.00M	$49.00M	$44.29M
YoY Change	10.87%	10.64%	14.05%
Other Assets	$15.00M	$12.00M	$16.00M
YoY Change	-73.68%	-25.0%	1500.0%
Total Long-Term Assets
YoY Change
TOTAL ASSETS
Total Short-Term Assets
Total Long-Term Assets
Total Assets	$13.22B	$12.81B	$13.45B
YoY Change	-0.75%	-4.75%	-10.88%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$547.0M	$499.0M	$456.0M
YoY Change	16.14%	9.43%	26.67%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$553.0M	$499.0M	$456.0M
YoY Change	17.41%	9.43%	16.62%
LONG-TERM LIABILITIES
Long-Term Debt	$7.232B	$6.906B	$7.308B
YoY Change	-1.95%	-5.5%	-14.27%
Other Long-Term Liabilities	$2.023B	$1.988B	$1.948B
YoY Change	11.77%	2.05%	9.44%
Total Long-Term Liabilities	$9.255B	$8.894B	$9.256B
YoY Change	0.75%	-3.91%	-10.17%
TOTAL LIABILITIES
Total Short-Term Liabilities	$553.0M	$499.0M	$456.0M
Total Long-Term Liabilities	$9.255B	$8.894B	$9.256B
Total Liabilities	$12.07B	$11.72B	$11.82B
YoY Change	2.47%	-0.88%	-11.35%
SHAREHOLDERS EQUITY
Retained Earnings	$759.0M	$773.0M	$1.313B
YoY Change	-36.91%	-41.13%
Common Stock	$0.00	$0.00	$456.0K
YoY Change		-100.0%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$1.000M	$1.000M	$347.0K
YoY Change		188.18%
Treasury Stock Shares	55.94K shares	55.94K shares	20.48K shares
Shareholders Equity	$1.080B	$1.035B	$1.569B
YoY Change
Total Liabilities & Shareholders Equity	$13.22B	$12.81B	$13.45B
YoY Change	-0.75%	-4.75%	-10.88%

Cashflow Statement

Concept	2020 Q4	2020 Q3	2019 Q3
OPERATING ACTIVITIES
Net Income	-$14.00M	-$108.0M	$66.00M
YoY Change	-87.27%	-263.64%	-163.46%
Depreciation, Depletion And Amortization	$17.00M	$14.00M	$17.50M
YoY Change	15.65%	-20.0%	-33.96%
Cash From Operating Activities	-$8.000M	-$55.00M	-$31.30M
YoY Change	-45.95%	75.72%	-70.56%
INVESTING ACTIVITIES
Capital Expenditures
YoY Change
Acquisitions
YoY Change
Other Investing Activities	$36.00M	$126.0M	$478.8M
YoY Change	-82.74%	-73.68%	104.62%
Cash From Investing Activities	$36.00M	$126.0M	$478.8M
YoY Change	-82.74%	-73.68%	104.62%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-43.00M	-55.00M	-425.4M
YoY Change	-76.16%	-87.07%	256.28%
NET CHANGE
Cash From Operating Activities	-8.000M	-55.00M	-31.30M
Cash From Investing Activities	36.00M	126.0M	478.8M
Cash From Financing Activities	-43.00M	-55.00M	-425.4M
Net Change In Cash	-15.00M	16.00M	22.10M
YoY Change	-211.94%	-27.6%	166.27%
FREE CASH FLOW
Cash From Operating Activities	-$8.000M	-$55.00M	-$31.30M
Capital Expenditures
Free Cash Flow
YoY Change

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	dei	Amendment Flag AmendmentFlag	false
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2020
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Entity Central Index Key EntityCentralIndexKey	0000874501
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2020Q3	us-gaap	Derivative Credit Risk Valuation Adjustment Derivative Liabilities DerivativeCreditRiskValuationAdjustmentDerivativeLiabilities	283000	USD
CY2019Q4	us-gaap	Derivative Credit Risk Valuation Adjustment Derivative Liabilities DerivativeCreditRiskValuationAdjustmentDerivativeLiabilities	19000	USD
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2020-09-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity File Number EntityFileNumber	1-10777
	dei	Entity Registrant Name EntityRegistrantName	AMBAC FINANCIAL GROUP, INC.
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	13-3621676
	dei	Entity Address Address Line1 EntityAddressAddressLine1	One World Trade Center
	dei	Entity Address City Or Town EntityAddressCityOrTown	New York
	dei	Entity Address State Or Province EntityAddressStateOrProvince	NY
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	10007
	dei	City Area Code CityAreaCode	(212)
	dei	Local Phone Number LocalPhoneNumber	658-7470
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
	dei	Entity Shell Company EntityShellCompany	false
	dei	Entity Bankruptcy Proceedings Reporting Current EntityBankruptcyProceedingsReportingCurrent	true
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CY2020Q3	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodTax	0	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodTax	0	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodTax	0	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodTax	0	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	0	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	0	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	2000000	USD
	us-gaap	Other Comprehensive Income Loss Financial Liability Fair Value Option Unrealized Gain Loss Arising During Period After Tax OtherComprehensiveIncomeLossFinancialLiabilityFairValueOptionUnrealizedGainLossArisingDuringPeriodAfterTax	0	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-37000000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Plan Amendments Tax Effect OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansPlanAmendmentsTaxEffect	0	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Plan Amendments Tax Effect OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansPlanAmendmentsTaxEffect	0	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Plan Amendments Tax Effect OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansPlanAmendmentsTaxEffect	0	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Plan Amendments Tax Effect OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansPlanAmendmentsTaxEffect	0	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	0	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	0	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	3000000	USD
	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	0	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	71000000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	7000000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-20000000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	75000000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-37000000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	73000000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-442000000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-30000000	USD
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-2.33
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.44
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-9.16
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-2.30
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-2.33
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.41
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-9.16
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-2.30
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	46178730	shares
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	45997694	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	46135399	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	45939284	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	46178730	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	47020058	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	46135399	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	45939284	shares
CY2020Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1129000000	USD
CY2020Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	3000000	USD
	ambc	Amps Impacton Stockholders Equity AMPSImpactonStockholdersEquity	19000000	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	0	USD
CY2020Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1095000000	USD
CY2019Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1553000000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	73000000	USD
CY2019Q3	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	2000000	USD
CY2019Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1629000000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1536000000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-442000000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	8000000	USD
	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-3000000	USD
CY2020Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1095000000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1633000000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-30000000	USD
	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	10000000	USD
	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	-3000000	USD
CY2019Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1629000000	USD
	us-gaap	Profit Loss ProfitLoss	-423000000	USD
	us-gaap	Profit Loss ProfitLoss	-106000000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	12000000	USD
	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	59000000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	8000000	USD
	us-gaap	Share Based Compensation ShareBasedCompensation	10000000	USD
	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	5000000	USD
	us-gaap	Increase Decrease In Deferred Income Taxes IncreaseDecreaseInDeferredIncomeTaxes	3000000	USD
	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	9000000	USD
	us-gaap	Increase Decrease In Accrued Income Taxes Payable IncreaseDecreaseInAccruedIncomeTaxesPayable	28000000	USD
	us-gaap	Increase Decrease In Unearned Premiums IncreaseDecreaseInUnearnedPremiums	-40000000	USD
	us-gaap	Increase Decrease In Unearned Premiums IncreaseDecreaseInUnearnedPremiums	-118000000	USD
	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	-78000000	USD
	us-gaap	Increase Decrease In Liability For Claims And Claims Adjustment Expense Reserve IncreaseDecreaseInLiabilityForClaimsAndClaimsAdjustmentExpenseReserve	461000000	USD
	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	-2000000	USD
	us-gaap	Increase Decrease In Reinsurance Payables IncreaseDecreaseInReinsurancePayables	-3000000	USD
	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	-44000000	USD
	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	-81000000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	69000000	USD
	us-gaap	Increase Decrease In Interest Payable Net IncreaseDecreaseInInterestPayableNet	65000000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	41000000	USD
	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	280000000	USD
	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	-1000000	USD
	us-gaap	Unrealized Gain Loss On Derivatives UnrealizedGainLossOnDerivatives	1000000	USD
	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	20000000	USD
	us-gaap	Realized Investment Gains Losses RealizedInvestmentGainsLosses	71000000	USD
	us-gaap	Variable Interest Entity Activity Between Vie And Entity Operating Income Or Loss VariableInterestEntityActivityBetweenVIEAndEntityOperatingIncomeOrLoss	3000000	USD
	us-gaap	Variable Interest Entity Activity Between Vie And Entity Operating Income Or Loss VariableInterestEntityActivityBetweenVIEAndEntityOperatingIncomeOrLoss	30000000	USD
	us-gaap	Increase Decrease In Derivative Assets And Liabilities IncreaseDecreaseInDerivativeAssetsAndLiabilities	-15000000	USD
	us-gaap	Increase Decrease In Derivative Assets And Liabilities IncreaseDecreaseInDerivativeAssetsAndLiabilities	-5000000	USD
	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-72000000	USD
	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-87000000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-167000000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	-296000000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities ProceedsFromSaleOfAvailableForSaleSecurities	974000000	USD
	us-gaap	Proceeds From Sale Of Available For Sale Securities ProceedsFromSaleOfAvailableForSaleSecurities	1052000000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	105000000	USD
	us-gaap	Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities	317000000	USD
	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	844000000	USD
	us-gaap	Payments To Acquire Available For Sale Securities PaymentsToAcquireAvailableForSaleSecurities	866000000	USD
	us-gaap	Proceeds From Sale And Maturity Of Other Investments ProceedsFromSaleAndMaturityOfOtherInvestments	377000000	USD
	us-gaap	Proceeds From Sale And Maturity Of Other Investments ProceedsFromSaleAndMaturityOfOtherInvestments	73000000	USD
	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	425000000	USD
	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	135000000	USD
	us-gaap	Payments For Proceeds From Short Term Investments PaymentsForProceedsFromShortTermInvestments	-67000000	USD
	us-gaap	Payments For Proceeds From Short Term Investments PaymentsForProceedsFromShortTermInvestments	235000000	USD
	us-gaap	Increase Decrease Cash Collateral From Counterparties IncreaseDecreaseCashCollateralFromCounterparties	-2000000	USD
	us-gaap	Increase Decrease Cash Collateral From Counterparties IncreaseDecreaseCashCollateralFromCounterparties	75000000	USD
	ambc	Proceeds From Financial Guaranty Variable Interest Entity Assets ProceedsFromFinancialGuarantyVariableInterestEntityAssets	142000000	USD
	ambc	Proceeds From Financial Guaranty Variable Interest Entity Assets ProceedsFromFinancialGuarantyVariableInterestEntityAssets	512000000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-2000000	USD
	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	0	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	396000000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	791000000	USD
	ambc	Proceeds From Issuanceof Ambac Uk Debt ProceedsFromIssuanceofAmbacUKDebt	0	USD
	ambc	Proceeds From Issuanceof Ambac Uk Debt ProceedsFromIssuanceofAmbacUKDebt	12000000	USD
	ambc	Paydownof Ambac Note PaydownofAmbacNote	115000000	USD
	ambc	Paydownof Ambac Note PaydownofAmbacNote	29000000	USD
	ambc	Amps Proceeds AMPSProceeds	0	USD
	ambc	Amps Proceeds AMPSProceeds	19000000	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	3000000	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	3000000	USD
	ambc	Paydownof Financial Guaranty Variable Interest Entity Liabilities PaydownofFinancialGuarantyVariableInterestEntityLiabilities	143000000	USD
	ambc	Paydownof Financial Guaranty Variable Interest Entity Liabilities PaydownofFinancialGuarantyVariableInterestEntityLiabilities	510000000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-260000000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-511000000	USD
	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents EffectOfExchangeRateOnCashAndCashEquivalents	0	USD
	us-gaap	Effect Of Exchange Rate On Cash And Cash Equivalents EffectOfExchangeRateOnCashAndCashEquivalents	0	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-31000000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-16000000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	81000000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	83000000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	50000000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	68000000	USD
	dei	Entity Incorporation Date Of Incorporation EntityIncorporationDateOfIncorporation	1991-04-29
	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	2000000	USD
	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	19000000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	11000000	USD
	us-gaap	Income Taxes Paid IncomeTaxesPaid	11000000	USD
	ambc	Non Cash Exchangeof Puerto Rico Bonds NonCashExchangeofPuertoRicoBonds	510000000	USD
CY2020Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	37000000	USD
CY2019Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	52000000	USD
CY2020Q3	us-gaap	Restricted Cash RestrictedCash	10000000	USD
CY2019Q3	us-gaap	Restricted Cash RestrictedCash	13000000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	50000000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	68000000	USD
	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<div style="margin-bottom:3pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-style:italic;font-weight:700;line-height:120%">Reclassifications and Rounding</span></div><div style="margin-bottom:9pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:120%">Reclassifications may have been made to prior years' amounts to conform to the current year's presentation. Certain amounts and tables in the consolidated financial statements and associated notes may not add due to rounding.</span></div>
	us-gaap	Description Of New Accounting Pronouncements Not Yet Adopted DescriptionOfNewAccountingPronouncementsNotYetAdopted	<div style="margin-bottom:3pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:700;line-height:120%">Future Application of Accounting Standards:</span></div><div style="margin-bottom:3pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-style:italic;font-weight:700;line-height:120%">Reference Rate Reform</span></div><div style="margin-bottom:9pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:120%">In March 2020, the FASB issued ASU 2020-04, </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-style:italic;font-weight:400;line-height:120%">Reference Rate Reform (Topic 848) - Facilitation of the Effects of Reference Rate Reform on Financial Reporting</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:120%">. The ASU provides companies with optional guidance to ease the potential accounting burden related to transitioning away from reference rates, such as LIBOR, that are expected to be discontinued as a result of initiatives undertaken by various jurisdictions around the world. For example, under current GAAP, contract modifications which change a reference rate are required to be evaluated in determining whether the modifications result in the establishment of new contracts or the continuation of existing contracts. The amendments in this ASU provide optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The ASU can be applied prospectively as of the beginning of the interim period that includes March 12, 2020, (January 1, 2020 for calendar year companies) or any date thereafter, but does not apply to contract modifications and other transactions entered into or evaluated after December 31, 2022. Management has not determined if and when it will adopt this ASU, and the impact on Ambac's financial statements is being evaluated.</span></div>
CY2020Q3	ambc	Variable Interest Entity Changein Fair Valueof Assetsand Liabilities VariableInterestEntityChangeinFairValueofAssetsandLiabilities	-1000000	USD
CY2019Q3	ambc	Variable Interest Entity Changein Fair Valueof Assetsand Liabilities VariableInterestEntityChangeinFairValueofAssetsandLiabilities	2000000	USD
	ambc	Variable Interest Entity Changein Fair Valueof Assetsand Liabilities VariableInterestEntityChangeinFairValueofAssetsandLiabilities	-3000000	USD
	ambc	Variable Interest Entity Changein Fair Valueof Assetsand Liabilities VariableInterestEntityChangeinFairValueofAssetsandLiabilities	7000000	USD
CY2020Q3	us-gaap	Variable Interest Entity Initial Consolidation Gain Or Loss VariableInterestEntityInitialConsolidationGainOrLoss	0	USD
CY2019Q3	us-gaap	Variable Interest Entity Initial Consolidation Gain Or Loss VariableInterestEntityInitialConsolidationGainOrLoss	0	USD
	us-gaap	Variable Interest Entity Initial Consolidation Gain Or Loss VariableInterestEntityInitialConsolidationGainOrLoss	0	USD
	us-gaap	Variable Interest Entity Initial Consolidation Gain Or Loss VariableInterestEntityInitialConsolidationGainOrLoss	15000000	USD
CY2020Q3	ambc	Variable Interest Entity Deconsolidation Gain Loss VariableInterestEntityDeconsolidationGainLoss	0	USD
CY2019Q3	ambc	Variable Interest Entity Deconsolidation Gain Loss VariableInterestEntityDeconsolidationGainLoss	-2000000	USD
	ambc	Variable Interest Entity Deconsolidation Gain Loss VariableInterestEntityDeconsolidationGainLoss	0	USD
	ambc	Variable Interest Entity Deconsolidation Gain Loss VariableInterestEntityDeconsolidationGainLoss	-2000000	USD
CY2020Q3	us-gaap	Variable Interest Entity Activity Between Vie And Entity Income Or Loss Before Tax VariableInterestEntityActivityBetweenVIEAndEntityIncomeOrLossBeforeTax	0	USD
CY2019Q3	us-gaap	Variable Interest Entity Activity Between Vie And Entity Income Or Loss Before Tax VariableInterestEntityActivityBetweenVIEAndEntityIncomeOrLossBeforeTax	11000000	USD
	us-gaap	Variable Interest Entity Activity Between Vie And Entity Income Or Loss Before Tax VariableInterestEntityActivityBetweenVIEAndEntityIncomeOrLossBeforeTax	3000000	USD
	us-gaap	Variable Interest Entity Activity Between Vie And Entity Income Or Loss Before Tax VariableInterestEntityActivityBetweenVIEAndEntityIncomeOrLossBeforeTax	30000000	USD
CY2020Q3	us-gaap	Variable Interest Entity Entity Maximum Loss Exposure Amount VariableInterestEntityEntityMaximumLossExposureAmount	28881000000	USD
CY2020Q3	ambc	Variable Interest Entity Nonconsolidated Carrying Amount Insurance Assets VariableInterestEntityNonconsolidatedCarryingAmountInsuranceAssets	2361000000	USD
CY2020Q3	ambc	Variable Interest Entity Nonconsolidated Carrying Amount Insurance Liabilities VariableInterestEntityNonconsolidatedCarryingAmountInsuranceLiabilities	1177000000	USD
CY2020Q3	ambc	Variable Interest Entity Nonconsolidated Carrying Amount Derivative Net Assets Or Liabilities VariableInterestEntityNonconsolidatedCarryingAmountDerivativeNetAssetsOrLiabilities	7000000	USD
CY2019Q4	us-gaap	Variable Interest Entity Entity Maximum Loss Exposure Amount VariableInterestEntityEntityMaximumLossExposureAmount	31506000000	USD
CY2019Q4	ambc	Variable Interest Entity Nonconsolidated Carrying Amount Insurance Assets VariableInterestEntityNonconsolidatedCarryingAmountInsuranceAssets	2247000000	USD
CY2019Q4	ambc	Variable Interest Entity Nonconsolidated Carrying Amount Insurance Liabilities VariableInterestEntityNonconsolidatedCarryingAmountInsuranceLiabilities	1083000000	USD
CY2020Q3	us-gaap	Equity Method Investments Fair Value Disclosure EquityMethodInvestmentsFairValueDisclosure	2000000	USD
CY2019Q4	us-gaap	Equity Method Investments Fair Value Disclosure EquityMethodInvestmentsFairValueDisclosure	3000000	USD
CY2020Q3	us-gaap	Equity Method Investments EquityMethodInvestments	49000000	USD
CY2019Q4	us-gaap	Equity Method Investments EquityMethodInvestments	46000000	USD
CY2020Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-48000000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	74000000	USD
CY2020Q3	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	3000000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	71000000	USD
CY2020Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	22000000	USD
CY2019Q2	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	19000000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	26000000	USD
CY2019Q3	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	19000000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	7000000	USD
CY2019Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	26000000	USD
CY2019Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	42000000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-2000000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	18000000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-20000000	USD
CY2020Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	22000000	USD
CY2018Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-49000000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	147000000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	72000000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	75000000	USD
CY2019Q3	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	26000000	USD
CY2020Q3	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	45809139	shares
CY2013Q2	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2020Q3	us-gaap	Class Of Warrant Or Right Outstanding ClassOfWarrantOrRightOutstanding	4877749	shares
CY2013Q2	us-gaap	Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1 ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1	16.67
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	46178730	shares
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	45997694	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	46135399	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	45939284	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	46178730	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	47020058	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	46135399	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	45939284	shares
CY2020Q3	ambc	Estimated Future Premium Payments Weighted Average Discounted Rate EstimatedFuturePremiumPaymentsWeightedAverageDiscountedRate	0.022
CY2019Q4	ambc	Estimated Future Premium Payments Weighted Average Discounted Rate EstimatedFuturePremiumPaymentsWeightedAverageDiscountedRate	0.024
	us-gaap	Financial Guarantee Insurance Contracts Premium Received Over Contract Period Premium Receivable Weighted Average Collection Period1 FinancialGuaranteeInsuranceContractsPremiumReceivedOverContractPeriodPremiumReceivableWeightedAverageCollectionPeriod1	P8Y6M
CY2019	us-gaap	Financial Guarantee Insurance Contracts Premium Received Over Contract Period Premium Receivable Weighted Average Collection Period1 FinancialGuaranteeInsuranceContractsPremiumReceivedOverContractPeriodPremiumReceivableWeightedAverageCollectionPeriod1	P8Y6M
CY2019Q4	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable FinancialGuaranteeInsuranceContractsPremiumReceivable	416000000	USD
CY2018Q4	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable FinancialGuaranteeInsuranceContractsPremiumReceivable	495000000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable Proceeds From Premiums Received FinancialGuaranteeInsuranceContractsPremiumReceivableProceedsFromPremiumsReceived	-36000000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable Proceeds From Premiums Received FinancialGuaranteeInsuranceContractsPremiumReceivableProceedsFromPremiumsReceived	-37000000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premiums Receivable Adjustment Change In Period Of Contract FinancialGuaranteeInsuranceContractsPremiumsReceivableAdjustmentChangeInPeriodOfContract	-4000000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premiums Receivable Adjustment Change In Period Of Contract FinancialGuaranteeInsuranceContractsPremiumsReceivableAdjustmentChangeInPeriodOfContract	-33000000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premiums Receivable Accretion Of Discount On Premium Receivable FinancialGuaranteeInsuranceContractsPremiumsReceivableAccretionOfDiscountOnPremiumReceivable	7000000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premiums Receivable Accretion Of Discount On Premium Receivable FinancialGuaranteeInsuranceContractsPremiumsReceivableAccretionOfDiscountOnPremiumReceivable	9000000	USD
	ambc	Financial Guarantee Insurance Contracts Premium Receivable Deconsolidation Of Vie FinancialGuaranteeInsuranceContractsPremiumReceivableDeconsolidationOfVIE	3000000	USD
	us-gaap	Premiums Receivable Allowance For Doubtful Accounts Period Increase Decrease PremiumsReceivableAllowanceForDoubtfulAccountsPeriodIncreaseDecrease	-5000000	USD
	us-gaap	Premiums Receivable Allowance For Doubtful Accounts Period Increase Decrease PremiumsReceivableAllowanceForDoubtfulAccountsPeriodIncreaseDecrease	-7000000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premiums Receivable Adjustment Other Adjustments FinancialGuaranteeInsuranceContractsPremiumsReceivableAdjustmentOtherAdjustments	-2000000	USD
	us-gaap	Financial Guarantee Insurance Contracts Premiums Receivable Adjustment Other Adjustments FinancialGuaranteeInsuranceContractsPremiumsReceivableAdjustmentOtherAdjustments	-16000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable FinancialGuaranteeInsuranceContractsPremiumReceivable	372000000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable FinancialGuaranteeInsuranceContractsPremiumReceivable	415000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Accelerated Premium Revenue Amount FinancialGuaranteeInsuranceContractsAcceleratedPremiumRevenueAmount	5000000	USD
	us-gaap	Financial Guarantee Insurance Contracts Accelerated Premium Revenue Amount FinancialGuaranteeInsuranceContractsAcceleratedPremiumRevenueAmount	6000000	USD
CY2019Q3	us-gaap	Financial Guarantee Insurance Contracts Accelerated Premium Revenue Amount FinancialGuaranteeInsuranceContractsAcceleratedPremiumRevenueAmount	2000000	USD
	us-gaap	Financial Guarantee Insurance Contracts Accelerated Premium Revenue Amount FinancialGuaranteeInsuranceContractsAcceleratedPremiumRevenueAmount	8000000	USD
CY2020Q3	us-gaap	Direct Premiums Written DirectPremiumsWritten	-13000000	USD
CY2020Q3	us-gaap	Direct Premiums Earned DirectPremiumsEarned	18000000	USD
CY2019Q3	us-gaap	Direct Premiums Written DirectPremiumsWritten	-13000000	USD
CY2019Q3	us-gaap	Direct Premiums Earned DirectPremiumsEarned	13000000	USD
CY2020Q3	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	0	USD
CY2020Q3	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	0	USD
CY2019Q3	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	0	USD
CY2019Q3	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	0	USD
CY2020Q3	us-gaap	Ceded Premiums Written CededPremiumsWritten	0	USD
CY2020Q3	us-gaap	Ceded Premiums Earned CededPremiumsEarned	3000000	USD
CY2019Q3	us-gaap	Ceded Premiums Written CededPremiumsWritten	23000000	USD
CY2019Q3	us-gaap	Ceded Premiums Earned CededPremiumsEarned	3000000	USD
CY2020Q3	us-gaap	Premiums Written Net PremiumsWrittenNet	-13000000	USD
CY2020Q3	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	15000000	USD
CY2019Q3	us-gaap	Premiums Written Net PremiumsWrittenNet	-36000000	USD
CY2019Q3	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	10000000	USD
	us-gaap	Direct Premiums Written DirectPremiumsWritten	-2000000	USD
	us-gaap	Direct Premiums Earned DirectPremiumsEarned	45000000	USD
	us-gaap	Direct Premiums Written DirectPremiumsWritten	-31000000	USD
	us-gaap	Direct Premiums Earned DirectPremiumsEarned	53000000	USD
	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	0	USD
	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	1000000	USD
	us-gaap	Assumed Premiums Written AssumedPremiumsWritten	0	USD
	us-gaap	Assumed Premiums Earned AssumedPremiumsEarned	0	USD
	us-gaap	Ceded Premiums Written CededPremiumsWritten	-1000000	USD
	us-gaap	Ceded Premiums Earned CededPremiumsEarned	9000000	USD
	us-gaap	Ceded Premiums Written CededPremiumsWritten	22000000	USD
	us-gaap	Ceded Premiums Earned CededPremiumsEarned	7000000	USD
	us-gaap	Premiums Written Net PremiumsWrittenNet	-2000000	USD
	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	36000000	USD
	us-gaap	Premiums Written Net PremiumsWrittenNet	-53000000	USD
	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	46000000	USD
CY2020Q3	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	15000000	USD
CY2019Q3	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	10000000	USD
	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	36000000	USD
	us-gaap	Premiums Earned Net Financial Guarantee Insurance Contracts PremiumsEarnedNetFinancialGuaranteeInsuranceContracts	46000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected During Fourth Quarter Following Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedDuringFourthQuarterFollowingBalanceSheetDate	11000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized During Fourth Quarter Following Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedDuringFourthQuarterFollowingBalanceSheetDate	10000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than One And Within Two Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThanOneAndWithinTwoYearsFromBalanceSheetDate	36000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than One And Within Two Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThanOneAndWithinTwoYearsFromBalanceSheetDate	35000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than Two And Within Three Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThanTwoAndWithinThreeYearsFromBalanceSheetDate	34000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than Two And Within Three Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThanTwoAndWithinThreeYearsFromBalanceSheetDate	33000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than Three And Within Four Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThanThreeAndWithinFourYearsFromBalanceSheetDate	33000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than Three And Within Four Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThanThreeAndWithinFourYearsFromBalanceSheetDate	30000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than Four And Within Five Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThanFourAndWithinFiveYearsFromBalanceSheetDate	31000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than Four And Within Five Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThanFourAndWithinFiveYearsFromBalanceSheetDate	29000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than Five And Within10 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThanFiveAndWithin10YearsFromBalanceSheetDate	138000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than Five And Within10 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThanFiveAndWithin10YearsFromBalanceSheetDate	120000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than10 And Within15 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThan10AndWithin15YearsFromBalanceSheetDate	101000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than10 And Within15 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThan10AndWithin15YearsFromBalanceSheetDate	81000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than15 And Within20 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThan15AndWithin20YearsFromBalanceSheetDate	50000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than15 And Within20 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThan15AndWithin20YearsFromBalanceSheetDate	37000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than20 And Within25 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThan20AndWithin25YearsFromBalanceSheetDate	22000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than20 And Within25 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThan20AndWithin25YearsFromBalanceSheetDate	14000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than25 And Within30 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThan25AndWithin30YearsFromBalanceSheetDate	9000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than25 And Within30 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThan25AndWithin30YearsFromBalanceSheetDate	5000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Expected To Be Collected More Than30 And Within35 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsPremiumExpectedToBeCollectedMoreThan30AndWithin35YearsFromBalanceSheetDate	1000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized More Than30 And Within35 Years From Balance Sheet Date FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognizedMoreThan30AndWithin35YearsFromBalanceSheetDate	1000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Premium Receivable Premium Expected To Be Collected FinancialGuaranteeInsuranceContractsPremiumReceivablePremiumExpectedToBeCollected	467000000	USD
CY2020Q3	us-gaap	Financial Guarantee Insurance Contracts Future Expected Premium Revenue To Be Recognized FinancialGuaranteeInsuranceContractsFutureExpectedPremiumRevenueToBeRecognized	395000000	USD
CY2020Q3	us-gaap	Premiums Receivable Gross PremiumsReceivableGross	390000000	USD
CY2020Q2	us-gaap	Allowance For Doubtful Accounts Premiums And Other Receivables AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables	16000000	USD
CY2019Q4	us-gaap	Allowance For Doubtful Accounts Premiums And Other Receivables AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables	9000000	USD
CY2020Q3	us-gaap	Premium Receivable Credit Loss Expense Reversal PremiumReceivableCreditLossExpenseReversal	2000000	USD
	us-gaap	Premium Receivable Credit Loss Expense Reversal PremiumReceivableCreditLossExpenseReversal	9000000	USD
CY2020Q3	us-gaap	Premiums Receivable Allowance For Doubtful Accounts Write Offs Against Allowance PremiumsReceivableAllowanceForDoubtfulAccountsWriteOffsAgainstAllowance	0	USD
	us-gaap	Premiums Receivable Allowance For Doubtful Accounts Write Offs Against Allowance PremiumsReceivableAllowanceForDoubtfulAccountsWriteOffsAgainstAllowance	0	USD
CY2020Q3	us-gaap	Premiums Receivable Allowance For Doubtful Accounts Recoveries PremiumsReceivableAllowanceForDoubtfulAccountsRecoveries	0	USD
	us-gaap	Premiums Receivable Allowance For Doubtful Accounts Recoveries PremiumsReceivableAllowanceForDoubtfulAccountsRecoveries	0	USD
CY2020Q3	us-gaap	Allowance For Doubtful Accounts Premiums And Other Receivables AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables	18000000	USD
CY2020Q3	us-gaap	Allowance For Doubtful Accounts Premiums And Other Receivables AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables	18000000	USD
CY2019Q4	us-gaap	Allowance For Doubtful Accounts Premiums And Other Receivables AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables	9000000	USD
CY2020Q3	us-gaap	Financing Receivable Recorded Investment Past Due FinancingReceivableRecordedInvestmentPastDue	2000000	USD
CY2020Q3	us-gaap	Financing Receivable Recorded Investment90 Days Past Due And Still Accruing FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing	2000000	USD
CY2020Q3	ambc	Reinsurance Recoverable Credit Exposure ReinsuranceRecoverableCreditExposure	1000000	USD
CY2020Q3	us-gaap	Reinsurance Recoverables Allowance ReinsuranceRecoverablesAllowance	0	USD
CY2020Q3	us-gaap	Liability Net For Claims And Claims Adjustment Expense Financial Guarantee Insurance Contracts LiabilityNetForClaimsAndClaimsAdjustmentExpenseFinancialGuaranteeInsuranceContracts	1801000000	USD
CY2019Q4	us-gaap	Liability Net For Claims And Claims Adjustment Expense Financial Guarantee Insurance Contracts LiabilityNetForClaimsAndClaimsAdjustmentExpenseFinancialGuaranteeInsuranceContracts	1548000000	USD
CY2020Q3	us-gaap	Salvage And Subrogation Recoveries Value SalvageAndSubrogationRecoveriesValue	2194000000	USD
CY2019Q4	us-gaap	Salvage And Subrogation Recoveries Value SalvageAndSubrogationRecoveriesValue	2029000000	USD
CY2020Q3	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Statement Of Financial Position Claim Liability ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationStatementOfFinancialPositionClaimLiability	-393000000	USD
CY2019Q4	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Statement Of Financial Position Claim Liability ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationStatementOfFinancialPositionClaimLiability	-482000000	USD
	us-gaap	Schedule Of Liability For Unpaid Claims And Claims Adjustment Expense ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense	<div style="margin-bottom:3pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:9pt;font-weight:400;line-height:120%">Below is the loss reserves roll-forward, net of subrogation recoverable and reinsurance, for the affected periods:</span></div><div style="margin-bottom:5pt;margin-top:9pt;text-align:justify"><table style="border-collapse:collapse;display:inline-table;vertical-align:top;width:99.371%"><tr><td style="width:1.0%"/><td style="width:58.710%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:18.203%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:1.382%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:18.205%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="9" style="padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Nine Months Ended September 30,</span></td></tr><tr><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2020</span></td><td colspan="3" style="border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">2019</span></td></tr><tr><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Beginning gross loss and loss expense reserves</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">(482)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">(107)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Reinsurance recoverable</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">26</span><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">23 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Beginning balance of net loss and loss expense reserves</span></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">(508)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">(130)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Losses and loss expenses (benefit):</span></td><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Current year</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">18</span><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">1 </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:11.25pt;text-indent:-4.5pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Prior years</span></div></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">198</span><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">(85)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:11.25pt;text-indent:-4.5pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Total </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:5.2pt;font-weight:400;line-height:100%;position:relative;top:-2.8pt;vertical-align:baseline">(1) (2)</span></div></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">216</span><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">(84)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:4.5pt;text-indent:-4.5pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Loss and loss expenses paid (recovered):</span></div></td><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Current year</span></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">1</span><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">— </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt 2px 6.75pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Prior years</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">137</span><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">299 </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:11.25pt;text-indent:-4.5pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Total</span></div></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">138</span><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">299 </span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:4.5pt;text-indent:-4.5pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Foreign exchange effect</span></div></td><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">1</span><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">(1)</span></td><td style="background-color:#ffffff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><div style="padding-left:4.5pt;text-indent:-4.5pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Ending net loss and loss expense reserves </span></div></td><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">(429)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;border-top:1pt solid #000000;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">(514)</span></td><td style="background-color:#cceeff;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Impact of VIE consolidation</span></td><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">—</span><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;padding:0 1pt"/><td colspan="2" style="background-color:#ffffff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">(72)</span></td><td style="background-color:#ffffff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#cceeff;padding:2px 1pt;text-align:left;vertical-align:bottom"><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">Reinsurance recoverable </span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:5.2pt;font-weight:400;line-height:100%;position:relative;top:-2.8pt;vertical-align:baseline">(3)</span></div></td><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">36</span><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%"> </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#cceeff;padding:0 1pt"/><td colspan="2" style="background-color:#cceeff;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:100%">26 </span></td><td style="background-color:#cceeff;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Ending gross loss and loss expense reserves</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#2a1aff;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">(393)</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/><td colspan="3" style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:0 1pt"/><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">$</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">(560)</span></td><td style="background-color:#ffffff;border-bottom:3pt double #000000;border-top:1pt solid #000000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div><div style="margin-bottom:3pt;margin-top:9pt;padding-left:18pt;text-align:justify;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%">(1)</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%;padding-left:8.68pt">Total losses and loss expenses (benefit) includes $(14) and $(6) for the nine months ended September 30, 2020 and 2019, respectively, related to ceded reinsurance.</span></div><div style="margin-bottom:3pt;padding-left:18pt;text-align:justify;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%">(2)</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%;padding-left:8.68pt">Ambac records the impact of estimated recoveries related to securitized loans in RMBS transactions that breached certain representations and warranties ("R&W's) by transaction sponsors within losses and loss expenses (benefit). The losses and loss expense (benefit) incurred associated with changes in estimated R&W's for the nine months ended September 30, 2020 and 2019, was $(29) and $15, respectively.</span></div><div style="margin-bottom:12pt;padding-left:18pt;text-align:justify;text-indent:-18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%">(3)</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:400;line-height:120%;padding-left:8.68pt">Represents reinsurance recoverable on future loss and loss expenses. Additionally, the Balance Sheet line "Reinsurance recoverable on paid and unpaid losses" includes reinsurance recoverables (payables) of $1 and $0 as of September 30, 2020 and 2019, respectively, related to previously presented loss and loss expenses and subrogation.</span></div>
CY2019Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	-482000000	USD
CY2018Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	-107000000	USD
CY2019Q4	ambc	Loss Reserves Ceded To Reinsurers LossReservesCededToReinsurers	26000000	USD
CY2018Q4	ambc	Loss Reserves Ceded To Reinsurers LossReservesCededToReinsurers	23000000	USD
CY2019Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	-508000000	USD
CY2018Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	-130000000	USD
	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	18000000	USD
	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	1000000	USD
	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	198000000	USD
	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	-85000000	USD
	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	216000000	USD
	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	-84000000	USD
	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	1000000	USD
	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	0	USD
	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	137000000	USD
	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	299000000	USD
	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	138000000	USD
	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	299000000	USD
	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Foreign Currency Translation Gain Loss LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseForeignCurrencyTranslationGainLoss	1000000	USD
	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Foreign Currency Translation Gain Loss LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseForeignCurrencyTranslationGainLoss	-1000000	USD
CY2020Q3	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	-429000000	USD
CY2019Q3	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	-514000000	USD
CY2020Q3	ambc	Impactof Vie Consolidationon Gross Lossand Loss Reserves ImpactofVIEConsolidationonGrossLossandLossReserves	0	USD
CY2019Q3	ambc	Impactof Vie Consolidationon Gross Lossand Loss Reserves ImpactofVIEConsolidationonGrossLossandLossReserves	72000000	USD
CY2020Q3	ambc	Loss Reserves Ceded To Reinsurers LossReservesCededToReinsurers	36000000	USD
CY2019Q3	ambc	Loss Reserves Ceded To Reinsurers LossReservesCededToReinsurers	26000000	USD
CY2020Q3	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	-393000000	USD
CY2019Q3	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	-560000000	USD
	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	14000000	USD
	us-gaap	Reinsurance Effect On Claims And Benefits Incurred Amount Ceded ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded	6000000	USD
	ambc	Net Incurred Rmbs Subrogation Recoveries NetIncurredRMBSSubrogationRecoveries	29000000	USD
	ambc	Net Incurred Rmbs Subrogation Recoveries NetIncurredRMBSSubrogationRecoveries	-15000000	USD
CY2020Q3	ambc	Ceded Loss And Loss Expenses Paid Not Yet Recovered CededLossAndLossExpensesPaidNotYetRecovered	1000000	USD
CY2019Q3	ambc	Ceded Loss And Loss Expenses Paid Not Yet Recovered CededLossAndLossExpensesPaidNotYetRecovered	0	USD
CY2020Q3	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Number Of Contracts Issued And Outstanding ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationNumberOfContractsIssuedAndOutstanding	242	Policies
	us-gaap	Insured Financial Obligations With Credit Deterioration Remaining Weighted Average Contract Period InsuredFinancialObligationsWithCreditDeteriorationRemainingWeightedAverageContractPeriod	P15Y
CY2020Q3	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Insured Contractual Payments Outstanding Principal ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationInsuredContractualPaymentsOutstandingPrincipal	7752000000	USD
CY2020Q3	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Insured Contractual Payments Outstanding Interest ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationInsuredContractualPaymentsOutstandingInterest	3639000000	USD
CY2020Q3	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Insured Contractual Payments Outstanding ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationInsuredContractualPaymentsOutstanding	11391000000	USD
CY2020Q3	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Gross Undiscounted Claim Liability ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationGrossUndiscountedClaimLiability	-2404000000	USD
CY2020Q3	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Discount On Gross Claim Liability ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationDiscountOnGrossClaimLiability	-259000000	USD
CY2020Q3	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Gross Claim Liability ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationGrossClaimLiability	-2145000000	USD
CY2020Q3	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Undiscounted Claim Liability Gross Undiscounted Rmbs Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossUndiscountedClaimLiabilityGrossUndiscountedRmbsSubrogation	1760000000	USD
CY2020Q3	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Discount On Rmbs Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossClaimLiabilityDiscountOnRmbsSubrogation	2000000	USD
CY2020Q3	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Rmbs Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossClaimLiabilityRmbsSubrogation	1757000000	USD
CY2020Q3	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Undiscounted Claim Liability Gross Undiscounted Other Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossUndiscountedClaimLiabilityGrossUndiscountedOtherSubrogation	799000000	USD
CY2020Q3	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Discount On Other Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossClaimLiabilityDiscountOnOtherSubrogation	18000000	USD
CY2020Q3	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Other Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossClaimLiabilityOtherSubrogation	781000000	USD
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CY2020Q3	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Statement Of Financial Position Unearned Premium Revenue ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationStatementOfFinancialPositionUnearnedPremiumRevenue	-80000000	USD
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CY2020Q3	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Statement Of Financial Position Claim Liability ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationStatementOfFinancialPositionClaimLiability	-393000000	USD
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CY2020Q3	ambc	Ceded Loss And Loss Expenses Paid Not Yet Recovered CededLossAndLossExpensesPaidNotYetRecovered	1000000	USD
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CY2019Q4	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Insured Contractual Payments Outstanding ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationInsuredContractualPaymentsOutstanding	9197000000	USD
CY2019Q4	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Gross Undiscounted Claim Liability ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationGrossUndiscountedClaimLiability	-2434000000	USD
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CY2019Q4	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Gross Claim Liability ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationGrossClaimLiability	-1893000000	USD
CY2019Q4	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Undiscounted Claim Liability Gross Undiscounted Rmbs Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossUndiscountedClaimLiabilityGrossUndiscountedRmbsSubrogation	1777000000	USD
CY2019Q4	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Discount On Rmbs Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossClaimLiabilityDiscountOnRmbsSubrogation	49000000	USD
CY2019Q4	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Rmbs Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossClaimLiabilityRmbsSubrogation	1727000000	USD
CY2019Q4	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Undiscounted Claim Liability Gross Undiscounted Other Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossUndiscountedClaimLiabilityGrossUndiscountedOtherSubrogation	720000000	USD
CY2019Q4	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Discount On Other Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossClaimLiabilityDiscountOnOtherSubrogation	53000000	USD
CY2019Q4	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Other Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossClaimLiabilityOtherSubrogation	666000000	USD
CY2019Q4	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Net Claim Liability ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationNetClaimLiability	501000000	USD
CY2019Q4	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Statement Of Financial Position Unearned Premium Revenue ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationStatementOfFinancialPositionUnearnedPremiumRevenue	-54000000	USD
CY2019Q4	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Loss Adjustment Expenses Reserve ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationLossAdjustmentExpensesReserve	73000000	USD
CY2019Q4	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Statement Of Financial Position Claim Liability ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationStatementOfFinancialPositionClaimLiability	-482000000	USD
CY2019Q4	us-gaap	Schedule Of Insured Financial Obligations With Credit Deterioration Statement Of Financial Position Reinsurance Recoverable ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationStatementOfFinancialPositionReinsuranceRecoverable	26000000	USD
CY2019Q4	ambc	Loss Reserves Ceded To Reinsurers LossReservesCededToReinsurers	26000000	USD
CY2019Q4	ambc	Ceded Loss And Loss Expenses Paid Not Yet Recovered CededLossAndLossExpensesPaidNotYetRecovered	0	USD
CY2020Q3	ambc	Public Finance Puerto Rico Net Par Outstanding PublicFinancePuertoRicoNetParOutstanding	1070000000	USD
CY2020Q3	ambc	Possible Increasein Domestic Public Finance Loss Reserves PossibleIncreaseinDomesticPublicFinanceLossReserves	1200000000	USD
CY2020Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1095000000	USD
CY2020Q3	ambc	Stockholders Equity After Possible Increasein Domestic Public Finance Loss Reserves StockholdersEquityAfterPossibleIncreaseinDomesticPublicFinanceLossReserves	-105000000	USD
CY2020Q3	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Rmbs Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossClaimLiabilityRmbsSubrogation	1757000000	USD
CY2020Q3	ambc	Balance Of Rmbs Subrogation Recoveries Net Of Reinsurance BalanceOfRmbsSubrogationRecoveriesNetOfReinsurance	-1731000000	USD
CY2019Q4	ambc	Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Rmbs Subrogation ScheduleOfInsuredFinancialObligationsWithCreditDeteriorationReductionsOfGrossClaimLiabilityRmbsSubrogation	1727000000	USD
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CY2020Q3	us-gaap	Intangible Assets Gross Excluding Goodwill IntangibleAssetsGrossExcludingGoodwill	1268000000	USD
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CY2020Q3	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	885000000	USD
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CY2019Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	427000000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Remainder Of Fiscal Year FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear	11000000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	39000000	USD
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CY2020Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	32000000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	29000000	USD
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CY2019Q3	ambc	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Deconsolidation Of Vies FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetOrLiabilityDeconsolidationOfVies	0	USD
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CY2020Q3	us-gaap	Available For Sale Securities Amortized Cost AvailableForSaleSecuritiesAmortizedCost	2914000000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Allowance For Credit Loss DebtSecuritiesAvailableForSaleAllowanceForCreditLoss	0	USD
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CY2020Q3	us-gaap	Available For Sale Securities Current AvailableForSaleSecuritiesCurrent	3048000000	USD
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CY2019Q4	us-gaap	Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax	132000000	USD
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CY2019Q4	us-gaap	Available For Sale Securities Current AvailableForSaleSecuritiesCurrent	3314000000	USD
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CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Within One Year Fair Value AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue	832000000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost	876000000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After One Through Five Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue	888000000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost	432000000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After Five Through Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue	453000000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Amortized Cost AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost	182000000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities After Ten Years Fair Value AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue	206000000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date Amortized Cost Basis AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis	2320000000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Maturities Single Maturity Date AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate	2379000000	USD
CY2020Q3	us-gaap	Available For Sale Debt Securities Amortized Cost Basis AvailableForSaleDebtSecuritiesAmortizedCostBasis	2914000000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	3048000000	USD
CY2020Q3	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	490000000	USD
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CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months	401000000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than12 Months Accumulated Loss DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss	4000000	USD
CY2019Q4	us-gaap	Debt Securities Available For Sale Continuous Unrealized Loss Position12 Months Or Longer DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger	88000000	USD
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CY2020Q3	us-gaap	Available For Sale Securities Gross Realized Gains AvailableForSaleSecuritiesGrossRealizedGains	5000000	USD
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CY2019Q3	us-gaap	Available For Sale Securities Gross Realized Losses AvailableForSaleSecuritiesGrossRealizedLosses	0	USD
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CY2020Q3	ambc	Fair Valueof Securities Depositedin Connectionwtih Letterof Credit FairValueofSecuritiesDepositedinConnectionwtihLetterofCredit	1000000	USD
CY2020Q3	ambc	Market Valueof Secured Note Collateral MarketValueofSecuredNoteCollateral	181000000	USD
CY2019Q4	ambc	Market Valueof Secured Note Collateral MarketValueofSecuredNoteCollateral	197000000	USD
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CY2020Q3	us-gaap	Interest And Dividend Income Securities Available For Sale InterestAndDividendIncomeSecuritiesAvailableForSale	24000000	USD
CY2019Q3	us-gaap	Interest And Dividend Income Securities Available For Sale InterestAndDividendIncomeSecuritiesAvailableForSale	36000000	USD
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CY2020Q3	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	126000000	USD
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CY2020Q3	us-gaap	Derivative Liabilities DerivativeLiabilities	126000000	USD
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CY2020Q3	ambc	Derivative Liabilities Net Amount DerivativeLiabilitiesNetAmount	2000000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	75000000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Asset Amount Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountOffsetAgainstCollateral	0	USD
CY2019Q4	us-gaap	Derivative Assets DerivativeAssets	75000000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Asset Amount Not Offset Against Collateral DerivativeFairValueOfDerivativeAssetAmountNotOffsetAgainstCollateral	0	USD
CY2019Q4	ambc	Derivative Assets Net Amount DerivativeAssetsNetAmount	75000000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	90000000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Liability Amount Offset Against Collateral DerivativeFairValueOfDerivativeLiabilityAmountOffsetAgainstCollateral	0	USD
CY2019Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	90000000	USD
CY2019Q4	ambc	Derivative Liabilities Gross Amount Of Collateral Cash And Securities Pledged Not Offset DerivativeLiabilitiesGrossAmountOfCollateralCashAndSecuritiesPledgedNotOffset	89000000	USD
CY2019Q4	ambc	Derivative Liabilities Net Amount DerivativeLiabilitiesNetAmount	1000000	USD
CY2020Q3	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	1000000	USD
CY2019Q4	us-gaap	Derivative Collateral Right To Reclaim Cash DerivativeCollateralRightToReclaimCash	36000000	USD
CY2020Q3	us-gaap	Derivative Collateral Obligation To Return Cash DerivativeCollateralObligationToReturnCash	0	USD
CY2020Q3	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	7000000	USD
CY2019Q3	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	-10000000	USD
	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	-61000000	USD
	us-gaap	Derivative Gain Loss On Derivative Net DerivativeGainLossOnDerivativeNet	-61000000	USD
CY2020Q3	ambc	Derivative Gain Losson Derivatives Total Net DerivativeGainLossonDerivativesTotalNet	-7000000	USD
CY2019Q3	ambc	Derivative Gain Losson Derivatives Total Net DerivativeGainLossonDerivativesTotalNet	-166000000	USD
	ambc	Derivative Gain Losson Derivatives Total Net DerivativeGainLossonDerivativesTotalNet	-231000000	USD
	ambc	Derivative Gain Losson Derivatives Total Net DerivativeGainLossonDerivativesTotalNet	-327000000	USD
CY2020Q3	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	124000000	USD
CY2019Q4	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	89000000	USD
CY2020Q3	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	144000000	USD
CY2019Q4	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	109000000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-106000000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	60000000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-412000000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-61000000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	-2000000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	9000000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	-15000000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	-11000000	USD
CY2020Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-108000000	USD
CY2019Q3	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	69000000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-427000000	USD
	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-72000000	USD
CY2020Q3	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	0	USD
CY2019Q3	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	0	USD
	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	0	USD
	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	0	USD
CY2020Q3	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	0	USD
CY2019Q3	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	0	USD
	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	0	USD
	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	-3000000	USD
CY2020Q3	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	-1000000	USD
CY2019Q3	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	4000000	USD
	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	0	USD
	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	38000000	USD
CY2020Q3	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-1000000	USD
CY2019Q3	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	4000000	USD
	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	1000000	USD
	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	35000000	USD
CY2020Q3	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	1000000	USD
CY2019Q3	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-1000000	USD
	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-5000000	USD
	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-2000000	USD
CY2020Q3	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	1000000	USD
CY2019Q3	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1000000	USD
	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-5000000	USD
	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-2000000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	0	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	3000000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-5000000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	33000000	USD
CY2011Q4	us-gaap	Operating Loss Carryforwards OperatingLossCarryforwards	3650000000	USD
CY2020Q3	ambc	Tier D Tolling Payments Payableto Irs TierDTollingPaymentsPayabletoIRS	0.175
CY2020Q3	ambc	Tier C Tolling Payments Payableto Irs TierCTollingPaymentsPayabletoIRS	0.125
	ambc	Aac Net Taxable Income AACNetTaxableIncome	1508000000	USD
CY2018Q4	ambc	Remaining Net Operating Loss Carryforward Amount RemainingNetOperatingLossCarryforwardAmount	2142000000	USD
CY2011Q4	us-gaap	Operating Loss Carryforwards OperatingLossCarryforwards	3650000000	USD
CY2020Q3	ambc	Tolling Payment Payableto Afg Gross TollingPaymentPayabletoAFGGross	28000000	USD
CY2011Q4	us-gaap	Operating Loss Carryforwards OperatingLossCarryforwards	3650000000	USD

Files In Submission

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0000874501-20-000131.txt	Edgar Link	pending
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$AMBC
AMBAC FINANCIAL GROUP INC Stock $ambc

2020 Q4 Form 10-Q Financial Statement

#000087450120000131 Filed on November 09, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$AMBC AMBAC FINANCIAL GROUP INC Stock $ambc

2020 Q4 Form 10-Q Financial Statement

#000087450120000131 Filed on November 09, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$AMBC
AMBAC FINANCIAL GROUP INC Stock $ambc