Ambac Financial (AMBC) 10-Q7 Aug 232023 Q2 Quarterly reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - $ / shares	6 Months Ended
Document and Entity Information - $ / shares	Jun. 30, 2023	Aug. 04, 2023	Apr. 30, 2013
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2023
Entity Ex Transition Period	false
Entity File Number	1-10777
Entity Registrant Name	AMBAC FINANCIAL GROUP, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-3621676
Entity Address, Address Line One	One World Trade Center
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10007
City Area Code	(212)
Local Phone Number	658-7470
Title of 12(b) Security	Common stock par value $0.01 per share
Trading Symbol	AMBC
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Bankruptcy Proceedings, Reporting Current	true
Entity Common Stock, Shares Outstanding		45,303,998
Common Stock, Par or Stated Value Per Share	$ 0.01		$ 0.01
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
Entity Central Index Key	0000874501
Current Fiscal Year End Date	--12-31

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Dec. 31, 2021
Assets:
Fixed maturity securities, at fair value	$ 1,953	$ 1,953
Total investments (net of allowance for credit losses of $1 and $0)	2,510	2,510	$ 2,593
Restricted Cash	10	10	14
Premiums Receivable, Net	276	276	269
Premium Receivable, Allowance for Credit Loss	5	5	5
Reinsurance Recoverables, Including Reinsurance Premium Paid	149	149	115
Deferred ceded premium	198	198	124
Subrogation recoverable	139	139	271
Derivative assets	26	26	27
Intangible assets	317	317	326
Goodwill	61	61	61	$ 46
Other assets	89	89	84
Total assets	8,132	8,132	7,973
Liabilities:
Unearned premiums	394	394	372
Loss and loss expense reserves	863	863	805
Ceded premiums payable	96	96	39
Long-term debt	501	501	639
Accrued interest payable	450	450	427
Derivative Liability	37	37	38
Other liabilities	136	136	163
Total liabilities	6,809	6,809	6,647
Redeemable Noncontrolling Interest, Equity, Carrying Amount	20	20	20	18
Liabilities	6,809	6,809	6,647
Stockholders’ equity:
Preferred stock, par value $0.01 per share; 20,000,000 shares authorized; issued and outstanding shares—none	0	0	0
Common Stock, Value, Issued	0	0	0
Additional paid-in capital	283	283	274
Accumulated other comprehensive income	(209)	(209)	(253)	58
Retained earnings	1,191	1,191	1,245
Treasury stock, shares at cost: 0 and 8,202	(15)	(15)	(15)
Total Ambac Financial Group, Inc. stockholders’ equity	1,250	1,250	1,252
Noncontrolling interest	53	53	53
Total stockholders’ equity	1,303	1,303	1,305	1,098
Total liabilities and stockholders’ equity	8,132	8,132	7,973
Debt Securities, Available-for-sale, Allowance for Credit Loss	1	1	0
Debt Securities, Available-for-sale, Amortized Cost	2,033	2,033	2,041
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	309	309	61	$ 23
Deferred Policy Acquisition Cost	4	4	3
Capitalized Contract Cost, Net	$ 6	$ 6	$ 5
Treasury Stock, Common, Shares	1,355,146	1,355,146	1,685,233
Afg [Member]
Stockholders’ equity:
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 43	$ 43	$ 44
Xchange
Liabilities:
Redeemable Noncontrolling Interest, Equity, Redemption Value	20	20
Redeemable Noncontrolling Interest, Equity, Carrying Amount			20
Short-term Investments [Member]
Assets:
Fixed maturity securities, at fair value	365	365	507
Stockholders’ equity:
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	0
Debt Securities, Available-for-sale, Amortized Cost	365	365	507
Variable Interest Entity, Primary Beneficiary [Member]
Assets:
Fixed maturity securities, at fair value	2,056	2,056	1,967
Restricted Cash	266	266	17
Derivative assets	224	224	239
Other assets	2	2	2
Total assets	4,320	4,320	4,054
Liabilities:
Long-term debt	2,956	2,956	3,107
Derivative Liability	1,106	1,106	1,048
Other Sundry Liabilities, Current	264	264
Other liabilities	1	1	5
Total liabilities	4,326	4,326	4,160
Liabilities	4,326	4,326	4,160
Stockholders’ equity:
Financing Receivable, after Allowance for Credit Loss	1,772	1,772	1,829
Gross Investment Income, Operating	3
Derivative and other assets	226	226	241
Fixed Income Securities [Member]
Assets:
Fixed maturity securities, at fair value	1,552	1,552	1,395
Stockholders’ equity:
Debt Securities, Available-for-sale, Allowance for Credit Loss	1	1	0
Debt Securities, Available-for-sale, Amortized Cost	1,632	1,632	1,469
Debt Securities, Available-for-Sale, Excluding Accrued Interest	1,552	1,552	1,395
Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss	1,631	1,631	1,469
Short-term Investments [Member]
Assets:
Fixed maturity securities, at fair value	365	365	507
Stockholders’ equity:
Gross Investment Income, Operating	5	10
Other Investments [Member]
Stockholders’ equity:
Other Investment Not Readily Marketable, Fair Value	530	530	568
Gross Investment Income, Operating	9	22
Fixed Income Securities, Trading
Stockholders’ equity:
Gross Investment Income, Operating	4	5
Debt Securities, Available-for-Sale, Excluding Accrued Interest	28	28	59
Collateral Pledged [Member] \| Fixed Income Securities [Member]
Assets:
Fixed maturity securities, at fair value	36	36	64
Collateral Pledged [Member] \| Fixed Income Securities [Member] \| Short-term Investments [Member]
Assets:
Fixed maturity securities, at fair value	36	36	64
Stockholders’ equity:
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	0
Debt Securities, Available-for-sale, Amortized Cost	36	36	64
Collateral Pledged [Member] \| Short-term Investments
Stockholders’ equity:
Debt Securities, Available-for-sale, Amortized Cost	36	36	64
Collateralized Securities \| Short-term Investments [Member]
Assets:
Fixed maturity securities, at fair value	$ 36	$ 36	$ 64

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale, Amortized Cost	$ 2,033	$ 2,041
Debt Securities, Available-for-sale, Allowance for Credit Loss	1	0
Premium Receivable, Allowance for Credit Loss	$ 5	$ 5
Preferred stock, par value	$ 0.01
Preferred stock, shares authorized	20,000,000
Preferred Stock, Shares Issued	0
Common stock, par value	$ 0.01
Common stock, shares authorized	130,000,000
Common stock, shares issued	46,659,144	46,658,990
Common stock, shares outstanding	45,303,998
Equity investments in pooled funds [Member]
Other Investment Not Readily Marketable, Fair Value	$ 518	$ 556
Variable Interest Entity, Primary Beneficiary [Member]
Long-term debt	$ 2,785	$ 2,788

Consolidated Statements of Tota

Consolidated Statements of Total Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Net investment income:
Interest and Dividend Income, Securities, Operating, Available-for-Sale	$ 22	$ 13	$ 43	$ 27
Net investment income (loss)	35	(21)	69	(16)
Realized Investment Gains (Losses)	(3)	7	(8)	17
Change in fair value of credit derivatives:
Derivative, Gain (Loss) on Derivative, Net	0	29	(3)	86
Insurance Commissions and Fees	10	6	25	15
Other Operating Income (Expense), Net	2	0	5	3
Income (loss) on variable interest entities	0	(6)	(1)	15
Total revenues and other income	62	86	120	206
Policyholder Benefits and Claims Incurred, Net	7	(12)	25	12
Expenses:
Intangible amortization	7	13	13	28
General and Administrative Expense	36	30	72	59
Interest expense	16	45	32	89
Total expenses	73	80	160	197
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(11)	6	(40)	9
Provision for income taxes	2	1	6	1
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	0	0	(1)	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(13)	5	(46)	8
Net income (loss) attributable to common stockholders	(13)	5	(47)	7
Other comprehensive income (loss), after tax
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(13)	5	(46)	8
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax	(13)	(72)	5	(177)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	21	(55)	37	(78)
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Arising During Period, after Tax	0	1	0	1
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	0	0	2	0
Total other comprehensive income (loss), net of income tax	8	(126)	44	(254)
Total comprehensive income (loss), net of income tax	(5)	(121)	(2)	(246)
Less: comprehensive (gain) loss attributable to the noncontrolling interest
Total comprehensive income (loss) attributable to common stockholders	(6)	(121)	(3)	(247)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest	$ 0	$ 0	$ (1)	$ 0
Earnings Per Share, Basic	$ (0.29)	$ 0.11	$ (1.02)	$ 0.15
Earnings Per Share, Diluted	$ (0.29)	$ 0.11	$ (1.02)	$ 0.15
Weighted Average Number of Shares Outstanding, Basic	45,757,234	45,519,093	45,661,288	46,121,927
Weighted Average Number of Shares Outstanding, Diluted	45,757,234	45,685,349	45,661,288	46,310,687
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Arising During Period, Tax	$ 0	$ 0	$ 0	$ 0
Gain (loss) on foreign currency translation, taxes	0	0	0	0
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Plan Amendments, Tax Effect	0	0	0	0
Premiums Earned, Net	15	14	29	28
Contractually Specified Servicing Fee, Late Fee, and Ancillary Fee Earned in Exchange for Servicing Financial Asset	2	1	4	1
Deferred Policy Acquisition Costs, Amortization Expense	1	0	3	0
General and Administrative Expense	36	30	72	59
Insurance Commissions	6	4	14	8
Net realized gains on extinguishment of debt	0	57	0	57
Unrealized (loss) gain on securities, taxes	(3)	(2)	(1)	(4)
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Arising During Period, Tax	0	0	0	0
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Plan Amendments, Tax Effect	0	0	0	0
Gain (loss) on foreign currency translation, taxes	$ 0	$ 0	$ 0	$ 0

Consolidated Statements of To_2

Consolidated Statements of Total Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Statement [Abstract]
Unrealized (loss) gain on securities, taxes	$ (3)	$ (2)	$ (1)	$ (4)
Gain (loss) on foreign currency translation, taxes	0	0	0	0
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Arising During Period, Tax	0	0	0	0
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Plan Amendments, Tax Effect	$ 0	$ 0	$ 0	$ 0

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Treasury Stock, Common	Noncontrolling Interest [Member]	Treasury Stock [Member]
Beginning balance at Dec. 31, 2021	$ 1,098	$ 0	$ 0	$ 257	$ 58	$ 726		$ 60	$ (3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	(247)
Stock-based compensation	10			10
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(3)					(5)		0	1
Ending balance at Jun. 30, 2022	846	0	0	267	(196)	728	$ (16)	62	(16)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury Stock, Value, Acquired, Cost Method	(14)								(14)
Total comprehensive income (loss)	(246)				(254)	7		0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(254)
Noncontrolling Interest, Change in Redemption Value	0
Proceeds from Noncontrolling Interests	2							2
Beginning balance at Mar. 31, 2022	974	0	0	262	(70)	723	(2)	60
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	(121)				(126)	5		0
Stock-based compensation	5			5
Ending balance at Jun. 30, 2022	846	0	0	267	(196)	728	(16)	62	(16)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury Stock, Value, Acquired, Cost Method	(14)								(14)
Total comprehensive income (loss)	(121)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(126)
Noncontrolling Interest, Change in Redemption Value	0
Proceeds from Noncontrolling Interests	2							2
Beginning balance at Dec. 31, 2022	1,305	0	0	274	(253)	1,245		53	(15)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	(3)
Stock-based compensation	8			8
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(5)					(8)		0	3
Ending balance at Jun. 30, 2023	1,303	0	0	283	(209)	1,191	(15)	53	(15)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury Stock, Value, Acquired, Cost Method	(3)								(3)
Total comprehensive income (loss)	(2)				44	(47)		0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	44
Noncontrolling Interest, Change in Redemption Value	0
Beginning balance at Mar. 31, 2023	1,307	0	0	278	(217)	1,206	(14)	53
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	(6)
Stock-based compensation	5			5
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	0	0	0	0	0	(2)	2	0
Ending balance at Jun. 30, 2023	1,303	$ 0	$ 0	$ 283	(209)	1,191	$ (15)	53	(15)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury Stock, Value, Acquired, Cost Method	(3)								$ (3)
Total comprehensive income (loss)	(5)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	8				$ 8	$ (13)		$ 0
Noncontrolling Interest, Change in Redemption Value	$ 0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities:
Net income attributable to common shareholders	$ (47)	$ 7
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	(1)	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Total	(46)	8
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation	1	1
Amortization of bond premium and discount	(6)	(6)
Share-based compensation	8	10
Unearned premiums, net	(51)	(25)
Losses and loss expenses, net	144	(13)
Ceded premiums payable	57	11
Premium receivables	(7)	12
Accrued interest payable	(26)	48
Amortization of Intangible Assets	13	28
Net investment gains (losses), including impairments	8	(17)
Variable interest entity activities	1	(15)
Derivative assets and liabilities	25	(54)
Other, net	(21)	81
Net Cash Provided by (Used in) Operating Activities, Total	101	11
Proceeds from Sale of Debt Securities, Available-for-Sale	107	387
Net Cash Provided by (Used in) Investing Activities [Abstract]
Proceeds from matured bonds	31	69
Purchases of bonds	(226)	(189)
Proceeds from sales of other invested assets	108	108
Purchases of other invested assets	(42)	(74)
Change in short-term investments	170	(2)
Change in cash collateral	(37)	56
Proceeds from paydowns of consolidated VIE assets	113	83
Other, net	10	2
Net cash provided by investing activities	489	440
Net Cash Provided by (Used in) Financing Activities [Abstract]
Tax payments related to shares withheld for share-based compensation plans	(8)	(3)
Proceeds from (Payments to) Noncontrolling Interests	(1)	1
Payments of consolidated VIE liabilities	(235)	(359)
Net cash used in financing activities	(343)	(434)
Effect of foreign exchange on cash, cash equivalents and restricted cash	1	(1)
Net cash flow	248	16
Cash, cash equivalents, and restricted cash at beginning of period	61	23
Cash, cash equivalents, and restricted cash at end of period	309	39
Change in cash collateral	(37)	56
Net realized gains on extinguishment of debt	0	(57)
Payment for Debt Extinguishment or Debt Prepayment Cost	0	(58)
Treasury Stock, Value, Acquired, Cost Method	(3)	(14)
Tier 2 Notes
Net Cash Provided by (Used in) Financing Activities [Abstract]
Repayments of Secured Debt	(97)	0
Repayments of Secured Debt	97	0
Variable Interest Entity, Primary Beneficiary [Member]
Net Cash Provided by (Used in) Investing Activities [Abstract]
Change in cash collateral	256	0
Change in cash collateral	$ 256	$ 0

Background and Business Descrip

Background and Business Description	6 Months Ended
Background and Business Description	Jun. 30, 2023
Accounting Policies [Abstract]
Background and Business Description	1. BACKGROUND AND BUSINESS DESCRIPTION The following description provides an update of Note 1. Background and Business Description in the Notes to the Consolidated Financial Statements included in Part II, Item 8 in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, and should be read in conjunction with the complete descriptions provided in the Form 10-K. Capitalized terms used, but not defined herein, and in the other footnotes to the Consolidated Financial Statements included in this Quarterly Report on Form 10-Q shall have the meanings ascribed thereto in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022. Ambac Financial Group, Inc. (“AFG”), headquartered in New York City, is a financial services holding company incorporated in the state of Delaware on April 29, 1991. References to “Ambac,” the “Company,” “we,” “our,” and “us” are to AFG and its subsidiaries, as the context requires. Ambac's principal businesses include: • Legacy Financial Guarantee Insurance — Ambac's financial guarantee business includes the activities of Ambac Assurance Corporation ("AAC") and its wholly owned subsidiaries, including Ambac Assurance UK Limited (“Ambac UK”) and Ambac Financial Services LLC ("AFS"). Both AAC and Ambac UK (the "Legacy Financial Guarantee Companies") have financial guarantee insurance portfolios that have been in runoff since 2008. AFS provided interest rate derivatives to financial guarantee customers and used derivatives to hedge interest rate risk in AAC's insurance and investment portfolios. As of June 30, 2023, AFS' only remaining derivative positions include a limited number of legacy customer swaps and their associated hedges. • Specialty Property & Casualty Insurance — Ambac's Specialty Property & Casualty Insurance program business. Currently includes five admitted carriers and an excess and surplus lines (“E&S” or “nonadmitted”) insurer (collectively, “Everspan”). Everspan carriers have an AM Best rating of 'A-' (Excellent) that was affirmed on June 13, 2023. • Insurance Distribution — Ambac's specialty property and casualty ("P&C") insurance distribution business, which could include Managing General Agents and Underwriters (collectively "MGAs"), insurance brokers, and other distribution businesses. Currently includes Xchange Benefits, LLC (“Xchange”), a P&C MGA specializing in accident and health products; All Trans Risk Solutions, LLC ("All Trans"), an MGA specializing in commercial automobile insurance for specific "for-hire" auto clauses; and Capacity Marine Corporation ("Capacity Marine"), a wholesale and retail brokerage and reinsurance intermediary specializing in marine and international risk. The Company reports these three business operations as segments; see Note 3. Segment Information for further information. Strategies to Enhance Shareholder Value The Company's primary goal is to maximize long-term shareholder value through the execution of targeted strategies for its (i) Specialty Property and Casualty Insurance and Insurance Distribution businesses and (ii) Legacy Financial Guarantee Insurance business. Specialty Property and Casualty Insurance and Insurance Distribution strategic priorities include: • Growing a Specialty Property and Casualty Insurance business which generates underwriting profits and an attractive return on capital from a diversified portfolio of commercial and personal liability risks accessed through program administrators. • Building an Insurance Distribution business based on deep domain knowledge in specialty and niche classes of risk which generate attractive margins at scale. This will be achieved through acquisitions, new business “de-novo” formation and incubation, and product expansion supported by a centralized technology led shared services offering. • Making opportunistic investments that are strategic to both the Specialty Property and Casualty Insurance and Insurance Distribution businesses. Legacy Financial Guarantee Insurance strategic priorities include: • Actively managing, de-risking and mitigating insured portfolio risk, and pursuing recovery of previously paid losses. • Improving operating efficiency and optimizing our asset and liability profile. • Exploring strategic options to further maximize value for AFG. The execution of Ambac’s strategy to increase the value of its investment in AAC is subject to the restrictions set forth in the Settlement Agreement, dated as of June 7, 2010, as amended (the "Settlement Agreement"), by and among AAC, Ambac Credit Products LLC ("ACP"), AFG and certain counterparties to credit default swaps with ACP that were guaranteed by AAC, as well as the Stipulation and Order among the Office of the Commissioner of Insurance for the State of Wisconsin (“OCI”), AFG and AAC that became effective on February 12, 2018, as amended (the “Stipulation and Order”), each of which requires OCI and, under certain circumstances, holders of surplus notes, to approve certain actions taken by or in respect of AAC. In exercising its approval rights, OCI will act for the benefit of policyholders, and will not take into account the interests of AFG. The Settlement Agreement limits certain activities of AAC and its subsidiaries, such as issuing indebtedness; engaging in mergers and similar transactions; disposing of assets; making restricted payments; creating or permitting liens; engaging in transactions with affiliates; modifying or creating tax sharing agreements; and taking certain actions with respect to surplus notes (among other restrictions and limitations). The Settlement Agreement includes certain allowances with respect to these activities and generally requires the approval of OCI and, in some cases, holders of surplus notes issued pursuant to the Settlement Agreement, for consents, waivers or amendments. The Stipulation and Order includes affirmative covenants, as well as restrictions on certain business activities and transactions, of AFG and AAC. The Stipulation and Order has no fixed term and may be terminated or modified only with the approval of OCI. OCI reserved the right to modify or terminate the Stipulation and Order in a manner consistent with the interests of policyholders, creditors and the public generally. The execution of Ambac’s strategy to increase the value of its investment in AAC may also be affected by a new capital framework being developed by OCI ("OCI's Runoff Capital Framework") to assist OCI with making decisions related to capital and liquidity management at AAC. OCI's Runoff Capital Framework is not yet complete and therefore we are not able to predict the results of such and what it may mean for our Legacy Financial Guarantee strategy, particularly as it relates to deleveraging AAC and distributing capital to AFG. Opportunities for remediating losses on poorly performing insured transactions also depend on market conditions, including the perception of AAC’s creditworthiness, the structure of the underlying risk and associated policy as well as other counterparty specific factors. AAC's ability to commute policies or purchase certain investments may also be limited by available liquidity.
Strategies to Enhance Shareholder Value	Strategies to Enhance Shareholder Value The Company's primary goal is to maximize long-term shareholder value through the execution of targeted strategies for its (i) Specialty Property and Casualty Insurance and Insurance Distribution businesses and (ii) Legacy Financial Guarantee Insurance business. Specialty Property and Casualty Insurance and Insurance Distribution strategic priorities include: • Growing a Specialty Property and Casualty Insurance business which generates underwriting profits and an attractive return on capital from a diversified portfolio of commercial and personal liability risks accessed through program administrators. • Building an Insurance Distribution business based on deep domain knowledge in specialty and niche classes of risk which generate attractive margins at scale. This will be achieved through acquisitions, new business “de-novo” formation and incubation, and product expansion supported by a centralized technology led shared services offering. • Making opportunistic investments that are strategic to both the Specialty Property and Casualty Insurance and Insurance Distribution businesses. Legacy Financial Guarantee Insurance strategic priorities include: • Actively managing, de-risking and mitigating insured portfolio risk, and pursuing recovery of previously paid losses. • Improving operating efficiency and optimizing our asset and liability profile. • Exploring strategic options to further maximize value for AFG. The execution of Ambac’s strategy to increase the value of its investment in AAC is subject to the restrictions set forth in the Settlement Agreement, dated as of June 7, 2010, as amended (the "Settlement Agreement"), by and among AAC, Ambac Credit Products LLC ("ACP"), AFG and certain counterparties to credit default swaps with ACP that were guaranteed by AAC, as well as the Stipulation and Order among the Office of the Commissioner of Insurance for the State of Wisconsin (“OCI”), AFG and AAC that became effective on February 12, 2018, as amended (the “Stipulation and Order”), each of which requires OCI and, under certain circumstances, holders of surplus notes, to approve certain actions taken by or in respect of AAC. In exercising its approval rights, OCI will act for the benefit of policyholders, and will not take into account the interests of AFG. The Settlement Agreement limits certain activities of AAC and its subsidiaries, such as issuing indebtedness; engaging in mergers and similar transactions; disposing of assets; making restricted payments; creating or permitting liens; engaging in transactions with affiliates; modifying or creating tax sharing agreements; and taking certain actions with respect to surplus notes (among other restrictions and limitations). The Settlement Agreement includes certain allowances with respect to these activities and generally requires the approval of OCI and, in some cases, holders of surplus notes issued pursuant to the Settlement Agreement, for consents, waivers or amendments. The Stipulation and Order includes affirmative covenants, as well as restrictions on certain business activities and transactions, of AFG and AAC. The Stipulation and Order has no fixed term and may be terminated or modified only with the approval of OCI. OCI reserved the right to modify or terminate the Stipulation and Order in a manner consistent with the interests of policyholders, creditors and the public generally. The execution of Ambac’s strategy to increase the value of its investment in AAC may also be affected by a new capital framework being developed by OCI ("OCI's Runoff Capital Framework") to assist OCI with making decisions related to capital and liquidity management at AAC. OCI's Runoff Capital Framework is not yet complete and therefore we are not able to predict the results of such and what it may mean for our Legacy Financial Guarantee strategy, particularly as it relates to deleveraging AAC and distributing capital to AFG. Opportunities for remediating losses on poorly performing insured transactions also depend on market conditions, including the perception of AAC’s creditworthiness, the structure of the underlying risk and associated policy as well as other counterparty specific factors. AAC's ability to commute policies or purchase certain investments may also be limited by available liquidity.

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies (Notes)	6 Months Ended
	Jun. 30, 2023
Accounting Policies [Abstract]
Organization, Consolidation and Presentation of Financial Statements Disclosure	2. BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES The Company has disclosed its significant accounting policies in Note 2. Basis of Presentation and Significant Accounting Policies in the Notes to Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022. The following significant accounting policies provide an update to those included in the Company’s Annual Report on Form 10-K. Consolidation: The consolidated financial statements include the accounts of AFG and all other entities in which AFG (directly or through its subsidiaries) has a controlling financial interest, including variable interest entities (“VIEs”) for which AFG or an AFG subsidiary is deemed the primary beneficiary in accordance with the Consolidation Topic of the Accounting Standards Codification ("ASC"). All significant intercompany balances have been eliminated. See Note 9. Variable Interest Entities , for a detailed discussion of Ambac’s involvement in VIEs, Ambac’s methodology for determining whether Ambac is required to consolidate a VIE and the effects of VIEs being consolidated and deconsolidated. Basis of Presentation: The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial reporting and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by GAAP for annual periods. These consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Annual Report on Form 10-K for the year ended December 31, 2022. The accompanying consolidated financial statements have not been audited by an independent registered public accounting firm in accordance with the standards of the Public Company Accounting Oversight Board (U.S.), but in the opinion of management such financial statements include all adjustments necessary for the fair presentation of the Company’s consolidated financial position and results of operations. The results of operations for the three and six months ended June 30, 2023, may not be indicative of the results that may be expected for the year ending December 31, 2023. The December 31, 2022, consolidated balance sheet was derived from audited financial statements. The preparation of financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. As additional information becomes available or actual amounts become determinable, the recorded estimates are revised and reflected in operating results. Foreign Currency: The impact of non-functional currency transactions and the remeasurement of non-functional currency assets and liabilities into the respective subsidiaries' functional currency (collectively "foreign currency transactions gains/(losses)") are $(3) and $7 for the six months ended June 30, 2023 and 2022, respectively. Foreign currency transactions gains/(losses) are primarily the result of remeasuring Ambac UK's assets and liabilities denominated in currencies (primarily the U.S. dollar and the Euro) other than its functional currency (the British Pound Sterling). Redeemable Noncontrolling Interest: The All Trans, Capacity Marine and Xchange acquisitions, further described in the in the Notes to Consolidated Financial Statements included in Part II, Item 8 in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, resulted in 85%, 80% and 80%, respectively, ownership of the acquired entities by Ambac. Under the terms of the acquisition agreements, Ambac has call options to purchase the remaining 15%, 20% and 20%, respectively, from the minority owners (i.e., noncontrolling interests) and the minority owners have put options to sell the remaining 15%, 20% and 20%, respectively, to Ambac. Because the exercise of the put options are outside the control of Ambac, in accordance with the Distinguishing Liabilities from Equity Topic of the ASC, Ambac reports redeemable noncontrolling interests in the mezzanine section of its consolidated balance sheet. The redeemable noncontrolling interest is remeasured each period as the greater of: i. the carrying value under ASC 810, which attributes a portion of consolidated net income (loss) to the redeemable noncontrolling interest, and ii. the redemption value of the put option under ASC 480 as if it were exercisable at the end of the reporting period. Any increase (decrease) in the carrying amount of the redeemable noncontrolling interest as a result of adjusting to the redemption value of the put option is recorded as an offset to retained earnings. The impact of such differences on earnings per share are presented in Note 12. Net Income Per Share . Following is a rollforward of redeemable noncontrolling interest. Six Months Ended June 30, 2023 2022 Beginning balance $ 20 $ 18 Net income attributable to redeemable noncontrolling interest (ASC 810) — — Adjustment to redemption value (ASC 480) — — Ending balance $ 20 $ 18 Supplemental Disclosure of Cash Flow Information Six Months Ended June 30, 2023 2022 Cash paid during the period for: Income taxes $ 6 $ 5 Interest on long-term debt 50 32 Non-cash investing and financing activities: Exchange of investments in Puerto Rico bonds for new securities issued in the restructuring transactions $ — $ 185 Securities acquired (transferred) in transactions related to Puerto Rico restructurings (1) — June 30, 2023 2022 Reconciliation of cash, cash equivalents, and restricted cash reported within the Cash and cash equivalents $ 33 $ 32 Restricted cash 10 5 Variable Interest Entity restricted cash 266 2 Total cash, cash equivalents, and restricted cash shown on the Consolidated Statements of Cash Flows $ 309 $ 39 Restricted cash is cash that we do not have the right to use for general purposes and includes fiduciary cash held by Ambac's insurance distribution subsidiaries and consolidated variable interest entity cash to support the obligations of the consolidated VIEs and cash received as collateral under their derivatives agreements. Reclassifications and Rounding 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. Adopted Accounting Standards: There have been no new accounting standards adopted during 2023. Future Application of Accounting Standards:

Segment Reporting

Segment Reporting	6 Months Ended
Segment Reporting	Jun. 30, 2023
Segment Reporting [Abstract]
Segment Reporting Disclosure	3. SEGMENT INFORMATION The Company reports its results of operations in three segments: Legacy Financial Guarantee Insurance, Specialty Property and Casualty Insurance and Insurance Distribution, separate from Corporate and Other, which is consistent with the manner in which the Company's chief operating decision maker ("CODM") reviews the business to assess performance and allocate resources. See Note 1. Background and Business Description for a description of each of the Company's business segments. The following tables summarize the components of the Company’s total revenues and expenses, pretax income (loss) and total assets by reportable business segment. Information provided below for “Corporate and Other” primarily relates to the operations of AFG, which will include investment income on its investment portfolio and costs to maintain the operations of AFG, including public company reporting, capital management and business development costs for the acquisition and development of new business initiatives. Three Months Ended June 30, 2023 Three Months Ended June 30, 2022 Legacy Financial Guarantee Insurance Specialty Property & Casualty Insurance Insurance Distribution Corporate & Other Consoli-dated (2) Legacy Financial Guarantee Insurance Specialty Property & Casualty Insurance Insurance Distribution Corporate & Other Consoli-dated (2) Revenues: Net premiums earned $ 8 $ 8 $ 15 $ 11 $ 3 $ 14 Commission income $ 10 10 $ 6 6 Program fees 2 2 1 1 Net investment income (loss) 32 1 $ 2 35 (22) — — $ 1 (21) Net investment gains (losses), including impairments (3) — — (3) 7 — — 7 Net gains (losses) on derivative contracts 1 — — 28 — 1 29 Net realized gains on extinguishment of debt — — — 57 — 57 Other (1) 2 — — — 3 (6) — — — (6) Total revenues (2) 39 11 10 2 62 75 4 6 2 86 Expenses: Losses and loss adjustment expenses 2 6 7 (14) 2 (12) Amortization of deferred acquisition costs, net — 1 1 — — — Commission expenses 6 6 4 4 General and administrative expenses (3) 23 4 2 6 36 23 3 2 1 29 Depreciation expense (3) — — — — — — — — — — Intangible amortization 6 1 7 13 1 13 Interest expense 16 — — 16 45 45 Total expenses (2) 47 11 9 6 73 68 5 6 1 80 Pretax income (loss) $ (8) $ — $ 1 $ (4) $ (11) $ 7 $ (1) $ — $ 1 $ 6 Total assets (2) $ 7,376 $ 395 $ 137 $ 225 $ 8,132 $ 9,579 $ 229 $ 94 $ 159 $ 10,061 Six Months Ended June 30, 2023 Six Months Ended June 30, 2022 Legacy Financial Guarantee Insurance Specialty Property & Casualty Insurance Insurance Distribution Corporate & Other Consoli-dated (2) Legacy Financial Guarantee Insurance Specialty Property & Casualty Insurance Insurance Distribution Corporate & Other Consoli-dated (2) Revenues: Net premiums earned $ 14 $ 15 $ 29 24 4 28 Commission income 25 25 15 15 Program fees 4 4 1 1 Net investment income (loss) 63 2 4 69 (18) 1 1 (16) Net investment gains (losses), including impairments (8) — — (8) 17 — — 17 Net gains (losses) on derivative contracts (3) — — (3) 85 — 1 86 Net realized gains on extinguishment of debt — — 57 — 57 Other (1) 4 — — — 4 18 — — — 18 Total revenues (2) 71 20 25 4 120 184 5 15 2 206 Expenses: Losses and loss adjustment expenses 15 10 25 9 3 12 Amortization of deferred acquisition costs, net — 3 3 — — — Commission expenses 14 14 8 8 General and administrative expenses (3) 52 8 5 7 72 44 6 3 4 58 Depreciation expense (3) 1 — — — 1 1 — — — 1 Intangible amortization 11 2 13 26 1 28 Interest expense $ 32 $ 32 $ 89 $ 89 Total expenses (2) 111 21 20 8 160 170 9 13 4 197 Pretax income (loss) (40) (1) 4 (3) (40) 13 (4) 2 (3) 9 (1) Other revenues include the following line item on the Consolidated Statements of Total Comprehensive Income: Income (loss) on variable interest entities and other income. (2) Inter-segment revenues and inter-segment pre-tax income (loss) amounts are insignificant and are not presented separately. Total assets noted in the Corporate and Other Column is net of AFG's investment in surplus notes issued by the Legacy Financial Guarantee Segment with fair values of $— and $61 at June 30, 2023 and 2022. (3) The Consolidated Statements of Comprehensive Income presents the sum of these items as General & Administrative Expenses.

Investments

Investments	6 Months Ended
Investments	Jun. 30, 2023
Investments, Debt and Equity Securities [Abstract]
Investments	4. INVESTMENTS Ambac’s non-VIE invested assets are primarily comprised of fixed maturity securities classified as either available-for-sale or trading securities, and interests in pooled investment funds, which are reported within Other investments on the Consolidated Balance Sheets. Interests in pooled investment funds in the form of common stock or in-substance common stock are classified as trading securities, while limited partner interests in such funds are reported using the equity method. Fixed maturity securities classified as trading are unrated municipal bond obligations of Puerto Rico issuing entities that are part of the the PROMESA restructuring process as described further in the Notes to Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 . Fixed Maturity Securities: The amortized cost and estimated fair value of available-for-sale investments, excluding VIE investments, at June 30, 2023 and December 31, 2022, were as follows: June 30, 2023: December 31, 2022: Amortized Allowance for Credit Losses (2) Gross Unrealized Estimated Amortized Allowance for Credit Losses Gross Unrealized Estimated Gains Losses Gains Losses Fixed maturity securities: Municipal obligations $ 64 $ — $ — $ 2 $ 63 $ 44 — $ — $ 2 $ 43 Corporate obligations 736 — — 62 674 659 — 1 63 598 Foreign obligations 94 — — 11 83 85 — — 9 76 U.S. government obligations 75 — — 4 71 68 — — 4 65 Residential mortgage-backed securities 230 1 26 17 238 230 — 28 19 238 Commercial mortgage-backed securities 16 — — — 16 15 — — — 15 Collateralized debt obligations 140 — — 3 138 141 — — 4 137 Other asset-backed securities (1) 275 — 3 10 268 227 — 2 5 224 1,632 1 30 109 1,552 1,469 — 31 106 1,395 Short-term 365 — — — 365 507 — — — 507 1,997 1 30 109 1,917 1,977 — 31 106 1,902 Fixed maturity securities pledged as collateral: Short-term 36 — — — 36 64 — — — 64 36 — — — 36 64 — — — 64 Total available-for-sale investments $ 2,033 $ 1 $ 30 $ 109 $ 1,953 $ 2,041 $ — $ 31 $ 106 $ 1,966 (1) Consists primarily of military housing and student loan securities. (2) For the three and six months ended June 30, 2023, the allowance for credit losses increased $0 and $1 on residential mortgage-backed securities on which credit losses were not previously recorded, respectively. The amortized cost and estimated fair value of available-for-sale investments, excluding VIE investments, at June 30, 2023, by contractual maturity, were as follows: Amortized Estimated Due in one year or less $ 464 $ 463 Due after one year through five years 554 518 Due after five years through ten years 291 257 Due after ten years 62 54 1,371 1,292 Residential mortgage-backed securities 230 238 Commercial mortgage-backed securities 16 16 Collateralized debt obligations 140 138 Other asset-backed securities 275 268 Total $ 2,033 $ 1,953 Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay certain obligations with or without call or prepayment penalties. Unrealized Losses on Fixed Maturity Securities: The following table shows gross unrealized losses and fair values of Ambac’s available-for-sale investments, excluding VIE investments, which at June 30, 2023 and December 31, 2022, did not have an allowance for credit losses under the CECL standard. This information is aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position, at June 30, 2023 and December 31, 2022: June 30, 2023 December 31, 2022 Less Than 12 Months 12 Months or More Total Less Than 12 Months 12 Months or More Total Fair Gross Fair Gross Fair Gross Fair Gross Fair Gross Fair Gross Fixed maturity securities: Municipal obligations $ 22 $ — $ 16 $ 2 $ 38 $ 2 $ 21 $ 1 $ 7 $ 1 $ 28 $ 2 Corporate obligations 209 9 447 53 656 62 280 21 279 42 559 63 Foreign obligations 36 2 47 9 83 11 27 2 47 7 73 9 U.S. government obligations 27 2 40 2 66 4 40 3 19 1 58 4 Residential mortgage-backed securities 74 2 91 15 165 17 132 19 — — 132 19 Commercial mortgage-backed securities 15 — — — 15 — 3 — — — 3 — Collateralized debt obligations — — 117 3 117 3 90 3 36 1 126 4 Other asset-backed securities 173 9 6 1 179 10 198 4 5 1 203 5 556 24 764 85 1,319 109 791 53 392 53 1,183 106 Short-term 37 — — — 37 — 78 — 8 — 86 — Total temporarily impaired securities $ 593 $ 24 $ 764 $ 85 $ 1,357 $ 109 $ 869 $ 53 $ 400 $ 53 $ 1,269 $ 106 Management has determined that the securities in the above table do not have credit impairment as of June 30, 2023 and December 31, 2022, based upon (i) no actual or expected principal and interest payment defaults on these securities; (ii) analysis of the creditworthiness of the issuer and financial guarantor, as applicable, and (iii) for debt securities that are non-highly rated beneficial interests in securitized financial assets, analysis of whether there was an adverse change in projected cash flows. Management's evaluation as of June 30, 2023, includes the expectation that all principal and interest payments on securities guaranteed by AAC or Ambac UK will be made timely and in full. Ambac’s assessment about whether a security is credit impaired reflects management’s current judgment regarding facts and circumstances specific to the security and other factors. If that judgment changes, Ambac may record a charge for credit impairment in future periods. The declines in fair value and resultant unrealized losses across asset classes as of June 30, 2023, included in the above table resulted from the impact of increasing interest rates and market spreads. Management has determined that the securities with unrealized losses are not credit impaired. Further discussion of management's assessment with respect to security categories with larger unrealized loss balances is below. Corporate obligations The gross unrealized losses on corporate obligations as of June 30, 2023, resulted from an increase in interest rates and, to a lesser extent, market spreads since the securities were purchased. Unrealized losses of $61 related to 838 investment grade securities with an average unrealized loss equal to 9% of amortized cost at June 30, 2023. Securities that have below investment grade credit ratings or are unrated comprise $1 of the gross unrealized loss and have an average unrealized loss equal to 6% of amortized cost at June 30, 2023. Management believes that the full and timely receipt of all principal and interest payment on corporate obligations with unrealized losses as of June 30, 2023, is probable. Residential mortgage-backed securities and Other asset-backed securities As of June 30, 2023, $17 of the unrealized loss on residential mortgage-backed securities related to 14 Ambac insured securities. Five of these account for $16 of the unrealized loss and have an average unrealized loss equal to 13% of amortized cost. The $10 unrealized loss on other asset backed securities related to 18 Ambac-insured securities that have an average unrealized loss equal to 5% of amortized cost. The majority of these unrealized losses for both residential mortgage-backed and other asset-backed securities relate to securities with long dated weighted average lives making their fair values more sensitive to interest rate changes. Also, most of these securities have below investment grade credit ratings or are unrated. The unrealized losses on these obligations resulted from adverse market conditions for long dated credit assets. As noted above, expected cash flows used in evaluating credit impairment of Ambac-insured securities contemplate full and timely payment of all principal and interest payments. This assumption is included in the projection of model based cash flows used in evaluating credit impairments on beneficial interests in securitized financial assets, including the residential mortgage backed and student loan asset backed securities included in this group. Investment Income (Loss) Net investment income (loss) was comprised of the following for the affected periods: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Fixed maturity securities $ 19 $ 13 $ 35 $ 28 Short-term investments 5 1 10 1 Investment expense (1) (1) (3) (3) Securities available-for-sale and short-term 22 13 43 27 Fixed maturity securities - trading 4 (11) 5 (21) Other investments 9 (23) 22 (23) Total net investment income (loss) $ 35 $ (21) $ 69 $ (16) Net investment income (loss) from Other investments primarily represents changes in fair value on equity securities, including certain pooled investment funds, and income from investment limited partnerships and other equity interests accounted for under the equity method. Net Investments Gains (Losses), including Impairments: The following table details amounts included in net investment gains (losses) and impairments included in earnings for the affected periods: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Gross realized gains on securities $ — $ — $ 1 $ 23 Gross realized losses on securities (2) (2) (3) (16) Foreign exchange gains (losses) (2) 8 (4) 11 Credit impairments — — (1) — Intent / requirement to sell impairments — — — — Net investment gains (losses), including impairments $ (3) $ 7 $ (8) $ 17 Ambac had an allowance for credit losses of $1 and $0 at June 30, 2023 and 2022, respectively. Ambac did not purchase any financial assets with credit deterioration for the three and six months ended June 30, 2023 and 2022. Counterparty Collateral, Deposits with Regulators and Other Restrictions: Ambac routinely pledges and receives collateral related to certain transactions. Securities held directly in Ambac’s investment portfolio with a fair value of $36 and $64 at June 30, 2023 and December 31, 2022, respectively, were pledged to derivative counterparties. Ambac’s derivative counterparties have the right to re-pledge the investment securities and as such, these pledged securities are separately classified on the Consolidated Balance Sheets as "Short-term investments pledged as collateral, at fair value." Refer to Note 7. Derivative Instruments for further information on cash collateral. There was no cash or securities received from other counterparties that were re-pledged by Ambac. Securities carried at $24 and $23 at June 30, 2023 and December 31, 2022, respectively, were deposited by Ambac's insurance subsidiaries with governmental authorities or designated custodian banks as required by laws affecting insurance companies. Invested assets carried at $1 and $1 at June 30, 2023 and December 31, 2022, were deposited as security in connection with a letter of credit issued for an office lease. Guaranteed Securities: Ambac’s fixed maturity portfolio includes securities covered by guarantees issued by AAC or Ambac UK (“insured securities”). The following table represents the fair value and weighted-average underlying rating of insured securities in Ambac's investment portfolio at June 30, 2023 and December 31, 2022, respectively: Municipal Mortgage Total Weighted (1) June 30, 2023: $ 9 $ 436 $ 446 B- December 31, 2022: $ 10 $ 394 $ 403 B (1) Ratings are based on the lower of Standard & Poor’s or Moody’s rating. If unavailable, Ambac’s internal rating is used. Other Investments: Ambac's investment portfolio includes interests in various pooled investment funds. Fair value and additional information about investments in pooled funds, by investment type, is summarized in the table below. Except as noted in the table, fair value as reported is determined using net asset value ("NAV") as a practical expedient. Redemption of certain funds valued using NAV may be subject to withdrawal limitations and/or redemption fees which vary with the timing and notification of withdrawal provided by the investor. In addition to these investments, Ambac has unfunded commitments of $52 to private credit and private equity funds at June 30, 2023. Fair Value Class of Funds June 30, December 31, 2022 Redemption Frequency Redemption Notice Period Hedge funds (1) $ 172 $ 186 quarterly or semi-annually 90 days Private credit (2) 85 84 quarterly if permitted 180 days if permitted High yields and leveraged loans (3) 74 80 daily 0 - 30 days Equity market investments (4) (10) 56 64 daily or quarterly 0 - 90 days Investment grade floating rate income (5) 41 63 weekly 0 days Private equity (6) 53 47 quarterly if permitted 90 days if permitted Real estate properties (7) 23 22 see footnote (7) see footnote (7) Convertible bonds (8)(10) 13 8 daily 0 days Insurance-linked investments (9) 1 1 see footnote (9) see footnote (9) Total equity investments in pooled funds $ 518 $ 556 (1) This class seeks to generate superior risk-adjusted returns through selective asset sourcing, active trading and hedging strategies across a range of asset types. (2) This class aims to obtain high long-term returns primarily through credit and preferred equity investments with low liquidity and defined term. (3) This class of funds includes investments in a range of instruments including high-yield bonds, leveraged loans, CLOs, ABS and floating rate notes to generate income and capital appreciation. (4) This class of funds aim to achieve long term growth through diversified exposure to global equity-markets. (5) This class of funds includes investments in high quality floating rate debt securities including ABS and corporate floating rate notes. (6) This class seeks to generate long-term capital appreciation through investments in private equity, equity-related and other instruments. (7) Investments consist of UK property to generate income and capital growth. In normal conditions, the fund allowed for quarterly redemptions with 10 days notice. The investment is currently restricted in connection with redemptions for a period of 12 months or longer. These restrictions are a result of redemption requests received by the fund in the calendar quarter or in aggregate in any rolling 12 month period, that exceed 10% or 15% of NAV of a portfolio, respectively. Ambac has requested full redemption of its interest in this fund. (8) This class seeks to generate total returns from portfolios focused primarily on convertible securities. (9) This class seeks to generate returns from insurance markets through investments in catastrophe bonds, life insurance and other insurance linked investments. This investment is restricted in connection with the unwind of certain insurance linked exposures. Ambac has redeemed its investment to the extent permitted by the fund. (10) These categories include fair value amounts totaling $69 and $61 at June 30, 2023 and December 31, 2022, respectively, that are readily determinable and are priced through pricing vendors, including for Equity market investments $56 and $53 and Convertible bonds investments $13 and $8.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
Fair Value Measurements	Jun. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	5. FAIR VALUE MEASUREMENTS The Fair Value Measurement Topic of the ASC establishes a framework for measuring fair value and disclosures about fair value measurements. Fair Value Hierarchy: The Fair Value Measurement Topic of the ASC specifies a fair value hierarchy based on whether the inputs to valuation techniques used to measure fair value are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect Company-based assumptions. The fair value hierarchy has three broad levels as follows: l Level 1 Quoted prices for identical instruments in active markets. Assets and liabilities classified as Level 1 include US Treasury and other foreign government obligations traded in highly liquid and transparent markets, certain highly liquid pooled fund investments, exchange traded futures contracts and money market funds. l Level 2 Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets. Assets and liabilities classified as Level 2 generally include investments in fixed maturity securities representing municipal, asset-backed and corporate obligations, certain interest rate swap contracts and most long-term debt of variable interest entities consolidated under the Consolidation Topic of the ASC. l Level 3 Model derived valuations in which one or more significant inputs or significant value drivers are unobservable. This hierarchy requires the use of observable market data when available. Assets and liabilities classified as Level 3 include certain uncollateralized interest rate swap contracts and certain investments in fixed maturity securities. Additionally, Level 3 assets and liabilities generally include loan receivables, and certain long-term debt of variable interest entities consolidated under the Consolidation Topic of the ASC. The Fair Value Measurement Topic of the ASC permits, as a practical expedient, the estimation of fair value of certain investments in funds using the net asset value per share of the investment or its equivalent (“NAV”). Investments in funds valued using NAV are not categorized as Level 1, 2 or 3 under the fair value hierarchy. The Investments — Equity Securities Topic of the ASC permits the measurement of certain equity securities without a readily determinable fair value at cost, less impairment, and adjusted to fair value when observable price changes in identical or similar investments from the same issuer occur (the "measurement alternative"). The fair values of investments measured under this measurement alternative are not included in the below disclosures of fair value of financial instruments. The following table sets forth the carrying amount and fair value of Ambac’s financial assets and liabilities as of June 30, 2023 and December 31, 2022, including the level within the fair value hierarchy at which fair value measurements are categorized. As required by the Fair Value Measurement Topic of the ASC, financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. June 30, 2023 December 31, 2022 Carrying Total Fair Fair Value Measurements Categorized as: Carrying Total Fair Fair Value Measurements Categorized as: Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Financial assets: Fixed maturity securities: Municipal obligations $ 90 $ 90 $ — $ 90 $ — $ 102 $ 102 $ — $ 102 $ — Corporate obligations 674 674 — 662 13 598 598 — 585 12 Foreign obligations 83 83 83 — — 76 76 76 — — U.S. government obligations 71 71 71 — — 65 65 65 — — Residential mortgage-backed securities 238 238 — 238 — 238 238 — 238 — Commercial mortgage-backed securities 16 16 — 16 — 15 15 — 15 — Collateralized debt obligations 138 138 — 138 — 137 137 — 137 — Other asset-backed securities 268 268 — 200 69 224 224 — 157 67 Fixed maturity securities, pledged as collateral: Short-term 36 36 36 — — 64 64 64 — — Short term investments 365 365 358 7 — 507 507 506 1 — Other investments (1) 530 518 69 — — 568 556 61 — — Cash, cash equivalents and restricted cash 43 43 43 — — 44 44 43 1 — Derivative assets: Interest rate swaps—asset position 25 25 — — 25 27 27 — 1 26 Warrants 1 1 — — 1 1 1 — — 1 Other assets-Loans 2 2 — — 2 10 10 — — 10 Variable interest entity assets: Fixed maturity securities: Corporate obligations, fair value option 1,952 1,952 — — 1,952 1,828 1,828 — — 1,828 Fixed maturity securities: Municipal obligation, trading — — — — — 43 43 — 43 — Fixed maturity securities: Municipal obligations, available-for-sale 104 104 — 104 — 96 96 — 96 — Restricted cash 266 266 266 — — 17 17 17 — — Loans 1,772 1,772 — — 1,772 1,829 1,829 — — 1,829 Derivative assets: Interest rate swaps—asset position 185 185 — 185 — 190 190 — 190 — Derivative assets: Currency swaps—asset position 39 39 — 39 — 49 49 — 49 — Total financial assets $ 6,899 $ 6,887 $ 926 $ 1,679 $ 3,833 $ 6,726 $ 6,715 $ 833 $ 1,615 $ 3,772 Financial liabilities: Long term debt, including accrued interest $ 951 $ 773 $ — $ 757 $ 16 $ 1,065 $ 878 $ — $ 864 $ 14 Derivative liabilities: Interest rate swaps—liability position 37 37 — 37 — 38 38 — 38 — Liabilities for net financial guarantees written (2) 311 727 — — 727 159 476 — — 476 Variable interest entity liabilities: Long-term debt 2,956 2,957 — 2,832 125 3,107 3,145 — 2,992 154 Derivative liabilities: Interest rate swaps—liability position 1,106 1,106 — 1,106 — 1,048 1,048 — 1,048 — Total financial liabilities $ 5,361 $ 5,600 $ — $ 4,732 $ 868 $ 5,418 $ 5,586 $ — $ 4,942 $ 644 (1) Excluded from the fair value measurement categories in the table above are investment funds of $449 and $494 as of June 30, 2023 and December 31, 2022, respectively, which are measured using NAV as a practical expedient. Also excluded from the fair value amounts in the table above are equity securities with a carrying value of $12 and $12 as of June 30, 2023 and December 31, 2022, respectively, that do not have readily determinable fair values and have carrying amounts determined using the measurement alternative. (2) The carrying value of net financial guarantees written includes financial guarantee amounts in the following balance sheet items: Premium receivables; Reinsurance recoverable on paid and unpaid losses; Deferred ceded premium; Subrogation recoverable; Insurance intangible asset; Unearned premiums; Loss and loss expense reserves; Ceded premiums payable, premiums taxes payable and other deferred fees recorded in Other liabilities. Determination of Fair Value: When available, Ambac uses quoted active market prices specific to the financial instrument to determine fair value, and classifies such items within Level 1. The determination of fair value for financial instruments categorized in Level 2 or 3 involves judgment due to the complexity of factors contributing to the valuation. Third-party sources from which we obtain independent market quotes also use assumptions, judgments and estimates in determining financial instrument values and different third parties may use different methodologies or provide different values for financial instruments. In addition, the use of internal valuation models may require assumptions about hypothetical or inactive markets. As a result of these factors, the actual trade value of a financial instrument in the market, or exit value of a financial instrument position by Ambac, may be significantly different from its recorded fair value. Ambac’s financial instruments carried at fair value are mainly comprised of investments in fixed maturity securities, equity interests in pooled investment funds, derivative instruments and certain variable interest entity assets and liabilities. Valuation of financial instruments is performed by Ambac’s finance group using methods approved by senior financial management with consultation from risk management and portfolio managers as appropriate. Preliminary valuation results are discussed with portfolio managers quarterly to assess consistency with market transactions and trends as applicable. Market transactions such as trades or negotiated settlements of similar positions, if any, are reviewed to validate fair value model results. However, financial instruments valued using significant unobservable inputs typically have very little or no observable market activity. Methods and significant inputs and assumptions used to determine fair values across portfolios are reviewed quarterly by senior financial management. Other valuation control procedures specific to particular portfolios are described further below. Fixed Maturity Securities: The fair values of fixed maturity investment securities are based primarily on market prices received from broker quotes or alternative pricing sources. Because many fixed maturity securities do not trade on a daily basis, pricing sources apply available market information through processes such as matrix pricing to calculate fair value. Such prices generally consider a variety of factors, including recent trades of the same and similar securities. In those cases, the items are classified within Level 2. For those fixed maturity investments where quotes were not available or cannot be reasonably corroborated, fair values are based on internal valuation models. Key inputs to the internal valuation models generally include maturity date, coupon and yield curves for asset-type and credit rating characteristics that closely match those characteristics of the specific investment securities being valued. Items valued using valuation models are classified according to the lowest level input or value driver that is significant to the valuation. Thus, an item may be classified in Level 3 even though there may be significant inputs that are readily observable. Longer (shorter) expected maturities or higher (lower) yields used in the valuation model will, in isolation, result in decreases (increases) in fair value. Generally, lower credit ratings or longer expected maturities will be accompanied by higher yields used to value a security. At June 30, 2023, approximately 2%, 94% and 4% of the fixed maturity investment portfolio (excluding variable interest entity investments) was valued using broker quotes, alternative pricing sources and internal valuation models, respectively. At December 31, 2022, approximately 5%, 91% and 4% of the fixed maturity investment portfolio (excluding variable interest entity investments) was valued using broker quotes, alternative pricing sources and internal valuation models, respectively. Ambac performs various review and validation procedures to quoted and modeled prices for fixed maturity securities, including price variance analyses, missing and static price reviews, overall valuation analysis by portfolio managers and finance managers and reviews associated with our ongoing impairment analysis. Unusual prices identified through these procedures will be evaluated further against alternative third party quotes (if available), internally modeled prices and/or other relevant data, and the pricing source values will be challenged as necessary. Price challenges generally result in the use of the pricing source’s quote as originally provided or as revised by the source following their internal diligence process. A price challenge may result in a determination by either the pricing source or Ambac management that the pricing source cannot provide a reasonable value for a security or cannot adequately support a quote, in which case Ambac would resort to using either other quotes or internal models. Results of price challenges are reviewed by portfolio managers and finance managers. Information about the valuation inputs for fixed maturity securities classified as Level 3 is included below: Other asset-backed securities: This security is a subordinated tranche of a securitization collateralized by Ambac-insured military housing bonds. The fair value classified as Level 3 was $69 and $67 at June 30, 2023 and December 31, 2022, respectively. Fair value was calculated using a discounted cash flow approach with expected future cash flows discounted using a yield consistent with the security type and rating. Significant inputs for the valuation at June 30, 2023 and December 31, 2022 include the following: June 30, 2023: a. Coupon rate: 5.98% b. Average Life: 13.13 years c. Yield: 12.00% December 31, 2022: a. Coupon rate: 5.98% b. Average Life: 13.46 years c. Yield: 12.60% Corporate obligations: This includes certain investments in convertible debt securities. The fair value classified as Level 3 was $13 and $12 at June 30, 2023 and December 31, 2022, respectively. Fair value was calculated by discounting cash flows to average maturity of 1.25 years and yield of 13.4% at June 30, 2023 and average maturity of 1.75 years and yield of 11.3% at December 31, 2022. Yields used are consistent with the security type and rating. Other Investments: Other investments primarily relate to investments in pooled investment funds. The fair value of pooled investment funds is determined using dealer quotes or alternative pricing sources when such investments have readily determinable fair values. When fair value is not readily determinable, pooled investment funds are valued using NAV as a practical expedient as permitted under the Fair Value Measurement Topic of the ASC. Refer to Note 4. Investments for additional information about such investments in pooled funds that are reported at fair value using NAV as a practical expedient. Derivative Instruments: Ambac’s derivative instruments primarily comprise interest rate swaps and exchange traded futures contracts. Fair value is determined based upon market quotes from independent sources, when available. When independent quotes are not available, fair value is determined using valuation models. These valuation models require market-driven inputs, including contractual terms, credit spreads, and yield curves. The valuation of certain derivative contracts may require the use of data inputs and assumptions that are determined by management and are not readily observable in the market. Under the Fair Value Measurement Topic of the ASC, Ambac is required to consider its own credit risk when measuring the fair value of derivative liabilities. Factors considered in estimating the amount of any Ambac credit valuation adjustment ("CVA") on such contracts include collateral posting provisions, right of set-off with the counterparty, the period of time remaining on the derivative and the pricing of recent terminations. The aggregate Ambac CVA impact was not significant to the fair value of derivatives at June 30, 2023 or December 31, 2022. Interest rate swaps that are not centrally cleared are valued using vendor-developed models that incorporate interest rates and yield curves that are observable and regularly quoted. These models provide the net present value of the derivatives based on contractual terms and observable market data. Generally, the need for counterparty (or Ambac) CVAs on interest rate derivatives is mitigated by the existence of collateral posting agreements under which adequate collateral has been posted. Certain of these derivative contracts entered into with financial guarantee customers are not subject to collateral posting agreements. Counterparty credit risk related to such customer derivative assets is included in our determination of their fair value. Ambac holds warrants to purchase preferred stock of a development stage company. These warrants have a fair value of $1 and $1 as of June 30, 2023 and December 31, 2022, respectively. Fair value was determined using a standard warrant valuation model with internally developed input assumptions. Financial Guarantees: Fair value of net financial guarantees written represents our estimate of the cost to Ambac to completely transfer its insurance obligation to another market participant of comparable credit worthiness. In theory, this amount should be the same amount that another market participant of comparable credit worthiness would hypothetically charge in the marketplace, on a present value basis, to provide the same protection as of the balance sheet date. This fair value estimate of financial guarantees is presented on a net basis and includes direct and assumed contracts written, net of ceded reinsurance contracts. Long-term Debt: Long-term debt includes AAC surplus notes, the Tier 2 Notes issued in connection with the Rehabilitation Exit Transactions (fully redeemed during the first quarter of 2023) and the Ambac UK debt issued in connection with the Ballantyne commutation. The fair values of surplus notes and Tier 2 Notes are classified as Level 2. The fair value of Ambac UK debt is classified as Level 3. Other Financial Assets and Liabilities: Included in Other assets are loans, the fair values of which are estimated based upon internal valuation models and are classified as Level 3. Variable Interest Entity Assets and Liabilities: The financial assets and liabilities of Legacy Financial Guarantee Insurance VIEs ("FG VIEs") consolidated under the Consolidation Topic of the ASC consist primarily of fixed maturity securities and loans held by the VIEs, derivative instruments and notes issued by the VIEs which are reported as long-term debt. As described in Note 9. Variable Interest Entities , these FG VIEs are securitization entities which have liabilities and/or assets guaranteed by AAC or Ambac UK. The fair values of FG VIE long-term debt are based on price quotes received from independent market sources when available. Such quotes are considered Level 2 and generally consider a variety of factors, including recent trades of the same and similar securities. For those instruments where quotes were not available or cannot be reasonably corroborated, fair values are based on internal valuation models. Comparable to the sensitivities of investments in fixed maturity securities described above, longer (shorter) expected maturities or higher (lower) yields used in the valuation model will, in isolation, result in decreases (increases) in fair value liability measurement for FG VIE long-term debt. FG VIE derivative asset and liability fair values are determined using vendor-developed valuation models, which incorporated observable market data related to specific derivative contractual terms including interest rates, foreign exchange rates and yield curves. The fair value of FG VIE fixed maturity securities and loan assets are generally based on Level 2 market price quotes received from independent market sources when available. When FG VIE asset fair values are not readily available from market quotes, values are estimated internally. Internal valuations of FG VIE’s fixed maturity securities or loan assets are derived from the fair values of the notes issued by the respective VIE and the VIE’s derivatives, determined as described above, adjusted for the fair values of Ambac’s financial guarantees associated with the VIE. The fair value of financial guarantees consist of: (i) estimated future premium cash flows discounted at a rate consistent with that implicit in the fair value of the VIE’s liabilities and (ii) estimates of future claim payments discounted at a rate that includes Ambac’s own credit risk. Estimated future premium payments to be paid by the VIEs were discounted at a weighted average rate of 7.5% and 6.8% at June 30, 2023 and December 31, 2022, respectively. At June 30, 2023, the range of these discount rates was between 6.2% and 9.4%. At December 31, 2022, the range of these discount rates were between 5.8% and 8.5%. Additional Fair Value Information for Financial Assets and Liabilities Accounted for at Fair Value: The following tables present the changes in the Level 3 fair value category for the periods presented in 2023 and 2022. Ambac classifies financial instruments in Level 3 of the fair value hierarchy when there is reliance on at least one significant unobservable input to the valuation model. In addition to these unobservable inputs, the valuation models for Level 3 financial instruments typically also rely on a number of inputs that are readily observable either directly or indirectly. Thus, the gains and losses presented below include changes in the fair value related to both observable and unobservable inputs. Level 3 - Financial Assets and Liabilities Accounted for at Fair Value VIE Assets Investments Derivatives Investments Loans Total Three Months Ended June 30, 2023: Balance, beginning of period $ 81 $ 31 $ 2,003 $ 1,856 $ 3,972 Total gains/(losses) realized and unrealized: Included in earnings — (5) (53) (66) (124) Included in other comprehensive income — — 14 50 64 Settlements — — (12) (69) (81) Balance, end of period $ 81 $ 25 $ 1,952 $ 1,772 $ 3,831 The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ — $ (5) $ (53) $ (66) $ (124) The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ — $ — $ 14 $ 50 $ 64 Three Months Ended June 30, 2022: Balance, beginning of period $ 86 $ 52 $ 3,131 $ 2,469 $ 5,738 Total gains/(losses) realized and unrealized: Included in earnings — (12) (365) (83) (460) Included in other comprehensive income (5) — (215) (174) (395) Settlements — (2) (18) (68) (88) Balance, end of period $ 81 $ 38 $ 2,533 $ 2,144 $ 4,795 The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ — $ (12) $ (365) $ (83) $ (460) The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ (5) $ — $ (215) $ (174) $ (395) Level 3 - Financial Assets and Liabilities Accounted for at Fair Value VIE Assets Investments Other Derivatives Investments Loans Total Six Months Ended June 30, 2023: Balance, beginning of period $ 79 $ — $ 26 $ 1,828 $ 1,829 $ 3,762 Total gains/(losses) realized and unrealized: Included in earnings 1 — — 80 (7) 73 Included in other comprehensive income 3 — — 57 92 152 Settlements (1) — — (12) (141) (155) Balance, end of period $ 81 $ — $ 25 $ 1,952 $ 1,772 $ 3,831 The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ 1 $ — $ — $ 80 $ (7) $ 73 The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ 3 $ — $ — $ 57 $ 92 $ 152 Six Months Ended June 30, 2022: Balance, beginning of period $ 91 $ — $ 70 $ 3,320 $ 2,718 $ 6,199 Total gains/(losses) realized and unrealized: Included in earnings 1 — (29) (458) (178) (664) Included in other comprehensive income (10) — — (311) (251) (572) Settlements (1) — (4) (18) (145) (168) Balance, end of period $ 81 $ — $ 38 $ 2,533 $ 2,144 $ 4,795 The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ 1 $ — $ (29) $ (458) $ (178) $ (664) The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ (10) $ — $ — $ (311) $ (251) (572) Invested assets and VIE long-term debt are transferred into Level 3 when internal valuation models that include significant unobservable inputs are used to estimate fair value. All such securities that have internally modeled fair values have been classified as Level 3. Derivative instruments are transferred into Level 3 when the use of unobservable inputs becomes significant to the overall valuation. There were no transfers of financial instruments into or out of Level 3 in the periods disclosed. Gains and losses (realized and unrealized) relating to Level 3 assets and liabilities included in earnings for the affected periods are reported as follows: Three Months Ended June 30, 2023 Three Months Ended June 30, 2022 Net Net Gains Income (Loss) Other Net Net Gains Income (Loss) Other Total gains (losses) included in earnings for the period $ — $ (5) $ (119) $ — $ — $ (12) $ (448) $ — Changes in unrealized gains (losses) relating to financial instruments still held at the reporting date — (5) (119) — — (12) (448) — Six Months Ended June 30, 2023 Six Months Ended June 30, 2022 Net Net Gains Income (Loss) Other Net Net Gains Income (Loss) Other Total gains or losses included in earnings for the period $ 1 $ — $ 72 $ — $ 1 $ (29) $ (636) $ — Changes in unrealized gains or losses included in earnings relating to the assets and liabilities still held at the reporting date — — 72 — — (29) (636) —

Insurance Contracts

Insurance Contracts	6 Months Ended
Insurance Contracts	Jun. 30, 2023
Insurance [Abstract]
Fair Value Measurements	5. FAIR VALUE MEASUREMENTS The Fair Value Measurement Topic of the ASC establishes a framework for measuring fair value and disclosures about fair value measurements. Fair Value Hierarchy: The Fair Value Measurement Topic of the ASC specifies a fair value hierarchy based on whether the inputs to valuation techniques used to measure fair value are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect Company-based assumptions. The fair value hierarchy has three broad levels as follows: l Level 1 Quoted prices for identical instruments in active markets. Assets and liabilities classified as Level 1 include US Treasury and other foreign government obligations traded in highly liquid and transparent markets, certain highly liquid pooled fund investments, exchange traded futures contracts and money market funds. l Level 2 Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs and significant value drivers are observable in active markets. Assets and liabilities classified as Level 2 generally include investments in fixed maturity securities representing municipal, asset-backed and corporate obligations, certain interest rate swap contracts and most long-term debt of variable interest entities consolidated under the Consolidation Topic of the ASC. l Level 3 Model derived valuations in which one or more significant inputs or significant value drivers are unobservable. This hierarchy requires the use of observable market data when available. Assets and liabilities classified as Level 3 include certain uncollateralized interest rate swap contracts and certain investments in fixed maturity securities. Additionally, Level 3 assets and liabilities generally include loan receivables, and certain long-term debt of variable interest entities consolidated under the Consolidation Topic of the ASC. The Fair Value Measurement Topic of the ASC permits, as a practical expedient, the estimation of fair value of certain investments in funds using the net asset value per share of the investment or its equivalent (“NAV”). Investments in funds valued using NAV are not categorized as Level 1, 2 or 3 under the fair value hierarchy. The Investments — Equity Securities Topic of the ASC permits the measurement of certain equity securities without a readily determinable fair value at cost, less impairment, and adjusted to fair value when observable price changes in identical or similar investments from the same issuer occur (the "measurement alternative"). The fair values of investments measured under this measurement alternative are not included in the below disclosures of fair value of financial instruments. The following table sets forth the carrying amount and fair value of Ambac’s financial assets and liabilities as of June 30, 2023 and December 31, 2022, including the level within the fair value hierarchy at which fair value measurements are categorized. As required by the Fair Value Measurement Topic of the ASC, financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. June 30, 2023 December 31, 2022 Carrying Total Fair Fair Value Measurements Categorized as: Carrying Total Fair Fair Value Measurements Categorized as: Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Financial assets: Fixed maturity securities: Municipal obligations $ 90 $ 90 $ — $ 90 $ — $ 102 $ 102 $ — $ 102 $ — Corporate obligations 674 674 — 662 13 598 598 — 585 12 Foreign obligations 83 83 83 — — 76 76 76 — — U.S. government obligations 71 71 71 — — 65 65 65 — — Residential mortgage-backed securities 238 238 — 238 — 238 238 — 238 — Commercial mortgage-backed securities 16 16 — 16 — 15 15 — 15 — Collateralized debt obligations 138 138 — 138 — 137 137 — 137 — Other asset-backed securities 268 268 — 200 69 224 224 — 157 67 Fixed maturity securities, pledged as collateral: Short-term 36 36 36 — — 64 64 64 — — Short term investments 365 365 358 7 — 507 507 506 1 — Other investments (1) 530 518 69 — — 568 556 61 — — Cash, cash equivalents and restricted cash 43 43 43 — — 44 44 43 1 — Derivative assets: Interest rate swaps—asset position 25 25 — — 25 27 27 — 1 26 Warrants 1 1 — — 1 1 1 — — 1 Other assets-Loans 2 2 — — 2 10 10 — — 10 Variable interest entity assets: Fixed maturity securities: Corporate obligations, fair value option 1,952 1,952 — — 1,952 1,828 1,828 — — 1,828 Fixed maturity securities: Municipal obligation, trading — — — — — 43 43 — 43 — Fixed maturity securities: Municipal obligations, available-for-sale 104 104 — 104 — 96 96 — 96 — Restricted cash 266 266 266 — — 17 17 17 — — Loans 1,772 1,772 — — 1,772 1,829 1,829 — — 1,829 Derivative assets: Interest rate swaps—asset position 185 185 — 185 — 190 190 — 190 — Derivative assets: Currency swaps—asset position 39 39 — 39 — 49 49 — 49 — Total financial assets $ 6,899 $ 6,887 $ 926 $ 1,679 $ 3,833 $ 6,726 $ 6,715 $ 833 $ 1,615 $ 3,772 Financial liabilities: Long term debt, including accrued interest $ 951 $ 773 $ — $ 757 $ 16 $ 1,065 $ 878 $ — $ 864 $ 14 Derivative liabilities: Interest rate swaps—liability position 37 37 — 37 — 38 38 — 38 — Liabilities for net financial guarantees written (2) 311 727 — — 727 159 476 — — 476 Variable interest entity liabilities: Long-term debt 2,956 2,957 — 2,832 125 3,107 3,145 — 2,992 154 Derivative liabilities: Interest rate swaps—liability position 1,106 1,106 — 1,106 — 1,048 1,048 — 1,048 — Total financial liabilities $ 5,361 $ 5,600 $ — $ 4,732 $ 868 $ 5,418 $ 5,586 $ — $ 4,942 $ 644 (1) Excluded from the fair value measurement categories in the table above are investment funds of $449 and $494 as of June 30, 2023 and December 31, 2022, respectively, which are measured using NAV as a practical expedient. Also excluded from the fair value amounts in the table above are equity securities with a carrying value of $12 and $12 as of June 30, 2023 and December 31, 2022, respectively, that do not have readily determinable fair values and have carrying amounts determined using the measurement alternative. (2) The carrying value of net financial guarantees written includes financial guarantee amounts in the following balance sheet items: Premium receivables; Reinsurance recoverable on paid and unpaid losses; Deferred ceded premium; Subrogation recoverable; Insurance intangible asset; Unearned premiums; Loss and loss expense reserves; Ceded premiums payable, premiums taxes payable and other deferred fees recorded in Other liabilities. Determination of Fair Value: When available, Ambac uses quoted active market prices specific to the financial instrument to determine fair value, and classifies such items within Level 1. The determination of fair value for financial instruments categorized in Level 2 or 3 involves judgment due to the complexity of factors contributing to the valuation. Third-party sources from which we obtain independent market quotes also use assumptions, judgments and estimates in determining financial instrument values and different third parties may use different methodologies or provide different values for financial instruments. In addition, the use of internal valuation models may require assumptions about hypothetical or inactive markets. As a result of these factors, the actual trade value of a financial instrument in the market, or exit value of a financial instrument position by Ambac, may be significantly different from its recorded fair value. Ambac’s financial instruments carried at fair value are mainly comprised of investments in fixed maturity securities, equity interests in pooled investment funds, derivative instruments and certain variable interest entity assets and liabilities. Valuation of financial instruments is performed by Ambac’s finance group using methods approved by senior financial management with consultation from risk management and portfolio managers as appropriate. Preliminary valuation results are discussed with portfolio managers quarterly to assess consistency with market transactions and trends as applicable. Market transactions such as trades or negotiated settlements of similar positions, if any, are reviewed to validate fair value model results. However, financial instruments valued using significant unobservable inputs typically have very little or no observable market activity. Methods and significant inputs and assumptions used to determine fair values across portfolios are reviewed quarterly by senior financial management. Other valuation control procedures specific to particular portfolios are described further below. Fixed Maturity Securities: The fair values of fixed maturity investment securities are based primarily on market prices received from broker quotes or alternative pricing sources. Because many fixed maturity securities do not trade on a daily basis, pricing sources apply available market information through processes such as matrix pricing to calculate fair value. Such prices generally consider a variety of factors, including recent trades of the same and similar securities. In those cases, the items are classified within Level 2. For those fixed maturity investments where quotes were not available or cannot be reasonably corroborated, fair values are based on internal valuation models. Key inputs to the internal valuation models generally include maturity date, coupon and yield curves for asset-type and credit rating characteristics that closely match those characteristics of the specific investment securities being valued. Items valued using valuation models are classified according to the lowest level input or value driver that is significant to the valuation. Thus, an item may be classified in Level 3 even though there may be significant inputs that are readily observable. Longer (shorter) expected maturities or higher (lower) yields used in the valuation model will, in isolation, result in decreases (increases) in fair value. Generally, lower credit ratings or longer expected maturities will be accompanied by higher yields used to value a security. At June 30, 2023, approximately 2%, 94% and 4% of the fixed maturity investment portfolio (excluding variable interest entity investments) was valued using broker quotes, alternative pricing sources and internal valuation models, respectively. At December 31, 2022, approximately 5%, 91% and 4% of the fixed maturity investment portfolio (excluding variable interest entity investments) was valued using broker quotes, alternative pricing sources and internal valuation models, respectively. Ambac performs various review and validation procedures to quoted and modeled prices for fixed maturity securities, including price variance analyses, missing and static price reviews, overall valuation analysis by portfolio managers and finance managers and reviews associated with our ongoing impairment analysis. Unusual prices identified through these procedures will be evaluated further against alternative third party quotes (if available), internally modeled prices and/or other relevant data, and the pricing source values will be challenged as necessary. Price challenges generally result in the use of the pricing source’s quote as originally provided or as revised by the source following their internal diligence process. A price challenge may result in a determination by either the pricing source or Ambac management that the pricing source cannot provide a reasonable value for a security or cannot adequately support a quote, in which case Ambac would resort to using either other quotes or internal models. Results of price challenges are reviewed by portfolio managers and finance managers. Information about the valuation inputs for fixed maturity securities classified as Level 3 is included below: Other asset-backed securities: This security is a subordinated tranche of a securitization collateralized by Ambac-insured military housing bonds. The fair value classified as Level 3 was $69 and $67 at June 30, 2023 and December 31, 2022, respectively. Fair value was calculated using a discounted cash flow approach with expected future cash flows discounted using a yield consistent with the security type and rating. Significant inputs for the valuation at June 30, 2023 and December 31, 2022 include the following: June 30, 2023: a. Coupon rate: 5.98% b. Average Life: 13.13 years c. Yield: 12.00% December 31, 2022: a. Coupon rate: 5.98% b. Average Life: 13.46 years c. Yield: 12.60% Corporate obligations: This includes certain investments in convertible debt securities. The fair value classified as Level 3 was $13 and $12 at June 30, 2023 and December 31, 2022, respectively. Fair value was calculated by discounting cash flows to average maturity of 1.25 years and yield of 13.4% at June 30, 2023 and average maturity of 1.75 years and yield of 11.3% at December 31, 2022. Yields used are consistent with the security type and rating. Other Investments: Other investments primarily relate to investments in pooled investment funds. The fair value of pooled investment funds is determined using dealer quotes or alternative pricing sources when such investments have readily determinable fair values. When fair value is not readily determinable, pooled investment funds are valued using NAV as a practical expedient as permitted under the Fair Value Measurement Topic of the ASC. Refer to Note 4. Investments for additional information about such investments in pooled funds that are reported at fair value using NAV as a practical expedient. Derivative Instruments: Ambac’s derivative instruments primarily comprise interest rate swaps and exchange traded futures contracts. Fair value is determined based upon market quotes from independent sources, when available. When independent quotes are not available, fair value is determined using valuation models. These valuation models require market-driven inputs, including contractual terms, credit spreads, and yield curves. The valuation of certain derivative contracts may require the use of data inputs and assumptions that are determined by management and are not readily observable in the market. Under the Fair Value Measurement Topic of the ASC, Ambac is required to consider its own credit risk when measuring the fair value of derivative liabilities. Factors considered in estimating the amount of any Ambac credit valuation adjustment ("CVA") on such contracts include collateral posting provisions, right of set-off with the counterparty, the period of time remaining on the derivative and the pricing of recent terminations. The aggregate Ambac CVA impact was not significant to the fair value of derivatives at June 30, 2023 or December 31, 2022. Interest rate swaps that are not centrally cleared are valued using vendor-developed models that incorporate interest rates and yield curves that are observable and regularly quoted. These models provide the net present value of the derivatives based on contractual terms and observable market data. Generally, the need for counterparty (or Ambac) CVAs on interest rate derivatives is mitigated by the existence of collateral posting agreements under which adequate collateral has been posted. Certain of these derivative contracts entered into with financial guarantee customers are not subject to collateral posting agreements. Counterparty credit risk related to such customer derivative assets is included in our determination of their fair value. Ambac holds warrants to purchase preferred stock of a development stage company. These warrants have a fair value of $1 and $1 as of June 30, 2023 and December 31, 2022, respectively. Fair value was determined using a standard warrant valuation model with internally developed input assumptions. Financial Guarantees: Fair value of net financial guarantees written represents our estimate of the cost to Ambac to completely transfer its insurance obligation to another market participant of comparable credit worthiness. In theory, this amount should be the same amount that another market participant of comparable credit worthiness would hypothetically charge in the marketplace, on a present value basis, to provide the same protection as of the balance sheet date. This fair value estimate of financial guarantees is presented on a net basis and includes direct and assumed contracts written, net of ceded reinsurance contracts. Long-term Debt: Long-term debt includes AAC surplus notes, the Tier 2 Notes issued in connection with the Rehabilitation Exit Transactions (fully redeemed during the first quarter of 2023) and the Ambac UK debt issued in connection with the Ballantyne commutation. The fair values of surplus notes and Tier 2 Notes are classified as Level 2. The fair value of Ambac UK debt is classified as Level 3. Other Financial Assets and Liabilities: Included in Other assets are loans, the fair values of which are estimated based upon internal valuation models and are classified as Level 3. Variable Interest Entity Assets and Liabilities: The financial assets and liabilities of Legacy Financial Guarantee Insurance VIEs ("FG VIEs") consolidated under the Consolidation Topic of the ASC consist primarily of fixed maturity securities and loans held by the VIEs, derivative instruments and notes issued by the VIEs which are reported as long-term debt. As described in Note 9. Variable Interest Entities , these FG VIEs are securitization entities which have liabilities and/or assets guaranteed by AAC or Ambac UK. The fair values of FG VIE long-term debt are based on price quotes received from independent market sources when available. Such quotes are considered Level 2 and generally consider a variety of factors, including recent trades of the same and similar securities. For those instruments where quotes were not available or cannot be reasonably corroborated, fair values are based on internal valuation models. Comparable to the sensitivities of investments in fixed maturity securities described above, longer (shorter) expected maturities or higher (lower) yields used in the valuation model will, in isolation, result in decreases (increases) in fair value liability measurement for FG VIE long-term debt. FG VIE derivative asset and liability fair values are determined using vendor-developed valuation models, which incorporated observable market data related to specific derivative contractual terms including interest rates, foreign exchange rates and yield curves. The fair value of FG VIE fixed maturity securities and loan assets are generally based on Level 2 market price quotes received from independent market sources when available. When FG VIE asset fair values are not readily available from market quotes, values are estimated internally. Internal valuations of FG VIE’s fixed maturity securities or loan assets are derived from the fair values of the notes issued by the respective VIE and the VIE’s derivatives, determined as described above, adjusted for the fair values of Ambac’s financial guarantees associated with the VIE. The fair value of financial guarantees consist of: (i) estimated future premium cash flows discounted at a rate consistent with that implicit in the fair value of the VIE’s liabilities and (ii) estimates of future claim payments discounted at a rate that includes Ambac’s own credit risk. Estimated future premium payments to be paid by the VIEs were discounted at a weighted average rate of 7.5% and 6.8% at June 30, 2023 and December 31, 2022, respectively. At June 30, 2023, the range of these discount rates was between 6.2% and 9.4%. At December 31, 2022, the range of these discount rates were between 5.8% and 8.5%. Additional Fair Value Information for Financial Assets and Liabilities Accounted for at Fair Value: The following tables present the changes in the Level 3 fair value category for the periods presented in 2023 and 2022. Ambac classifies financial instruments in Level 3 of the fair value hierarchy when there is reliance on at least one significant unobservable input to the valuation model. In addition to these unobservable inputs, the valuation models for Level 3 financial instruments typically also rely on a number of inputs that are readily observable either directly or indirectly. Thus, the gains and losses presented below include changes in the fair value related to both observable and unobservable inputs. Level 3 - Financial Assets and Liabilities Accounted for at Fair Value VIE Assets Investments Derivatives Investments Loans Total Three Months Ended June 30, 2023: Balance, beginning of period $ 81 $ 31 $ 2,003 $ 1,856 $ 3,972 Total gains/(losses) realized and unrealized: Included in earnings — (5) (53) (66) (124) Included in other comprehensive income — — 14 50 64 Settlements — — (12) (69) (81) Balance, end of period $ 81 $ 25 $ 1,952 $ 1,772 $ 3,831 The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ — $ (5) $ (53) $ (66) $ (124) The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ — $ — $ 14 $ 50 $ 64 Three Months Ended June 30, 2022: Balance, beginning of period $ 86 $ 52 $ 3,131 $ 2,469 $ 5,738 Total gains/(losses) realized and unrealized: Included in earnings — (12) (365) (83) (460) Included in other comprehensive income (5) — (215) (174) (395) Settlements — (2) (18) (68) (88) Balance, end of period $ 81 $ 38 $ 2,533 $ 2,144 $ 4,795 The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ — $ (12) $ (365) $ (83) $ (460) The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ (5) $ — $ (215) $ (174) $ (395) Level 3 - Financial Assets and Liabilities Accounted for at Fair Value VIE Assets Investments Other Derivatives Investments Loans Total Six Months Ended June 30, 2023: Balance, beginning of period $ 79 $ — $ 26 $ 1,828 $ 1,829 $ 3,762 Total gains/(losses) realized and unrealized: Included in earnings 1 — — 80 (7) 73 Included in other comprehensive income 3 — — 57 92 152 Settlements (1) — — (12) (141) (155) Balance, end of period $ 81 $ — $ 25 $ 1,952 $ 1,772 $ 3,831 The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ 1 $ — $ — $ 80 $ (7) $ 73 The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ 3 $ — $ — $ 57 $ 92 $ 152 Six Months Ended June 30, 2022: Balance, beginning of period $ 91 $ — $ 70 $ 3,320 $ 2,718 $ 6,199 Total gains/(losses) realized and unrealized: Included in earnings 1 — (29) (458) (178) (664) Included in other comprehensive income (10) — — (311) (251) (572) Settlements (1) — (4) (18) (145) (168) Balance, end of period $ 81 $ — $ 38 $ 2,533 $ 2,144 $ 4,795 The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ 1 $ — $ (29) $ (458) $ (178) $ (664) The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ (10) $ — $ — $ (311) $ (251) (572) Invested assets and VIE long-term debt are transferred into Level 3 when internal valuation models that include significant unobservable inputs are used to estimate fair value. All such securities that have internally modeled fair values have been classified as Level 3. Derivative instruments are transferred into Level 3 when the use of unobservable inputs becomes significant to the overall valuation. There were no transfers of financial instruments into or out of Level 3 in the periods disclosed. Gains and losses (realized and unrealized) relating to Level 3 assets and liabilities included in earnings for the affected periods are reported as follows: Three Months Ended June 30, 2023 Three Months Ended June 30, 2022 Net Net Gains Income (Loss) Other Net Net Gains Income (Loss) Other Total gains (losses) included in earnings for the period $ — $ (5) $ (119) $ — $ — $ (12) $ (448) $ — Changes in unrealized gains (losses) relating to financial instruments still held at the reporting date — (5) (119) — — (12) (448) — Six Months Ended June 30, 2023 Six Months Ended June 30, 2022 Net Net Gains Income (Loss) Other Net Net Gains Income (Loss) Other Total gains or losses included in earnings for the period $ 1 $ — $ 72 $ — $ 1 $ (29) $ (636) $ — Changes in unrealized gains or losses included in earnings relating to the assets and liabilities still held at the reporting date — — 72 — — (29) (636) —

Derivative Instruments

Derivative Instruments	6 Months Ended
Derivative Instruments	Jun. 30, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	7. DERIVATIVE INSTRUMENTS The following tables summarize the gross fair values of individual derivative instruments and the impact of legal rights of offset as reported in the Consolidated Balance Sheets as of June 30, 2023 and December 31, 2022: June 30, 2023 December 31, 2022 Gross Gross Net Amounts Gross Amount Net Gross Gross Net Amounts Gross Amount Net Derivative Assets: Interest rate swaps $ 25 $ — $ 25 $ — $ 25 $ 27 $ — $ 27 $ — $ 27 Warrants 1 — 1 — 1 1 — 1 — 1 Total non-VIE derivative assets $ 26 $ — $ 26 $ — $ 26 $ 28 $ — $ 27 $ — $ 27 Derivative Liabilities: Interest rate swaps $ 37 $ — $ 37 $ 36 $ — $ 38 $ — $ 38 $ 38 $ — Total non-VIE derivative liabilities $ 37 $ — $ 37 $ 36 $ — $ 38 $ — $ 38 $ 38 $ — Variable Interest Entities Derivative Assets: Interest rate swaps $ 185 $ — $ 185 $ 184 $ 1 $ 190 $ — $ 190 $ — $ 190 Currency swaps 39 — 39 39 — 49 — 49 — 49 Total VIE derivative assets $ 224 $ — $ 224 $ 223 $ 1 $ 239 $ — $ 239 $ — $ 239 Variable Interest Entities Derivative Liabilities: Interest rate swaps $ 1,106 $ — $ 1,106 $ — $ 1,106 $ 1,048 $ — $ 1,048 $ — $ 1,048 Total VIE derivative liabilities $ 1,106 $ — $ 1,106 $ — $ 1,106 $ 1,048 $ — $ 1,048 $ — $ 1,048 Amounts representing the right to reclaim cash collateral or the obligation to return cash collateral are not offset against fair value amounts recognized for derivative instruments on the Unaudited Consolidated Balance Sheets. The amounts representing the right to reclaim cash collateral and posted margin, recorded in “Other assets” were $17 and $6 as of June 30, 2023 and December 31, 2022, respectively. Amounts representing an obligation to return cash collateral were $263 and $0 as of June 30, 2023 and December 31, 2022, respectively and are reported in "Variable interest entity liabilities: Other liabilities". The following tables summarize the location and amount of gains and losses of derivative contracts in the Unaudited Consolidated Statements of Total Comprehensive Income (Loss) for the three and six months ended June 30, 2023 and 2022: Location of Gain (Loss) Amount of Gain (Loss) Recognized in Consolidated Statement of Total Comprehensive Income (Loss) Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Non-VIE derivatives: Interest rate swaps Net gains (losses) on derivative contracts 1 17 (3) 47 Warrants Net gains (losses) on derivative contracts — 1 — 1 Futures contracts Net gains (losses) on derivative contracts — 11 — 37 Total Non-VIE derivatives $ — $ 29 (3) 86 Variable Interest Entities: Currency swaps Income (loss) on variable interest entities $ (1) $ 14 (3) 20 Interest rate swaps Income (loss) on variable interest entities 97 264 (2) 269 Total Variable Interest Entities 96 278 (5) 289 Total derivative contracts $ 97 $ 307 $ (8) $ 376 Interest Rate Derivatives: AFS provided interest rate derivatives to financial guarantee customers and used derivatives to provide a partial hedge against interest rate risk in AAC's insurance and investment portfolios. Additionally, AFS provided interest rate swaps to states, municipalities and their authorities, asset-backed issuers and other entities in connection with their financings. As of June 30, 2023, AFS's only remaining derivative positions include a limited number of legacy customer swaps and their associated hedges. As of June 30, 2023 and December 31, 2022, the notional amounts of AFS’s derivatives are as follows: Notional Type of Derivative June 30, December 31, Interest rate swaps—pay-fixed/receive-variable $ 142 $ 989 Interest rate swaps—receive-fixed/pay-variable 170 337 Other Derivatives: As of June 30, 2023 Ambac holds warrants to purchase preferred stock of a development stage company. Derivatives of Consolidated Variable Interest Entities Certain VIEs consolidated under the Consolidation Topic of the ASC entered into derivative contracts to meet specified purposes within the securitization structure. The notional amounts for VIE derivatives outstanding as of June 30, 2023 and December 31, 2022, were as follows: Notional Type of VIE Derivative June 30, December 31, Interest rate swaps—receive-fixed/pay-variable $ 1,655 $ 1,573 Interest rate swaps—pay-fixed/receive-variable 898 887 Currency swaps 163 176 Contingent Features in Derivatives Related to Ambac Credit Risk Certain of Ambac's interest rate swaps remain with professional swap-dealer counterparties executed under standardized derivative documents including collateral support and master netting agreements. Under these agreements, Ambac is required to post collateral in the event net unrealized losses exceed predetermined threshold levels. Additionally, given that AAC is no longer rated by an independent rating agency, counterparties have the right to terminate the swap positions. As of June 30, 2023 and December 31, 2022, the net liability fair value of derivative instruments with contingent features linked to Ambac’s own credit risk was $36 and $38, respectively, related to which Ambac had posted cash and securities as collateral with a fair value of $54 and $54, respectively. All such ratings-based contingent features have been triggered requiring maximum collateral levels to be posted by Ambac while preserving counterparties’ rights to terminate the contracts. Assuming all such contracts terminated at fair value on June 30, 2023, settlement of collateral balances and net derivative liabilities would result in a net receipt of cash and/or securities by Ambac. If counterparties elect to exercise their right to terminate, the actual termination payment amounts will be determined in accordance with derivative contract terms, which may result in amounts that differ from market values as reported in Ambac’s financial statements.

Intangible Assets

Intangible Assets	6 Months Ended
Intangible Assets	Jun. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets Disclosure [Text Block]	8. GOODWILL AND INTANGIBLE ASSETS See Note 2. Basis of Presentation and Significant Accounting Policies for discussion of goodwill. The following table presents the Company's goodwill. June 30, December 31, Beginning balance $ 61 $ 46 Business acquisitions — 15 Impairments — — Ending balance $ 61 $ 61 Intangible assets and accumulated amortization are included in the Consolidated Balance Sheets, as shown below. June 30, December 31, Finite-lived Intangible Assets: Insurance intangible: Gross carrying value $ 1,257 $ 1,247 Accumulated amortization 999 981 Net insurance intangible asset 258 266 Other intangibles: Gross carrying value 52 52 Accumulated amortization 7 6 Net other intangible assets 45 47 Total finite-lived intangible assets 303 312 Indefinite-lived Intangible Assets: Insurance licenses 14 14 Total intangible assets $ 317 $ 326

Revenue Recognition and Deferre

Revenue Recognition and Deferred Revenue	6 Months Ended
Revenue Recognition and Deferred Revenue	Jun. 30, 2023
Revenue Recognition and Deferred Revenue [Abstract]
Revenue from Contract with Customer	The following table presents the Insurance Distribution business operations revenues recognized in accordance with the Revenue from Contracts with Customers Topic of the ASC disaggregated by policy type for the affected periods: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Employer Stop Loss $ 2 $ 1 $ 7 $ 5 Affinity Products 5 5 10 9 Commercial Auto 2 — 5 — Other 1 — 2 — Total $ 10 $ 6 $ 25 $ 15 During the six months ended June 30, 2023 and 2022, the amount of revenue recognized related to performance obligations satisfied in a previous period, inclusive of changes due to estimates was approximately $5 and $5, respectively. Contract Assets and Liabilities The balances of contract assets and contract liabilities with customers were as follows: June 30, 2023 December 31, 2022 Premiums and commissions receivable $ 6 $ 7 Contract assets 9 5 Contract liabilities 1 1 Contract assets represent estimated future consideration related to base commissions and profit-sharing commissions that were recognized as revenue upon the placement of the policy. The Company does not have the right to bill or collect payment on i) base commissions until the related premiums from policyholders has been collected nor ii) profit-sharing commissions until after the contract year is completed. Changes in contract assets during the six months ended June 30, 2023, is primarily due to the timing of new or renewal policies, growth in the business, reclassifications to receivables (unconditional right) and collections.

Comprehensive Income

Comprehensive Income	6 Months Ended
Comprehensive Income	Jun. 30, 2023
Equity [Abstract]
Comprehensive Income	11. COMPREHENSIVE INCOME The following tables detail the changes in the balances of each component of accumulated other comprehensive income for the affected periods: Three Months Ended June 30, 2023: Three Months Ended June 30, 2022: Unrealized Gains (1) Amortization of Postretirement Benefit (1) Gain (Loss) on Foreign Currency (1) Credit Risk Changes of Fair Value Option Liabilities (1) (2) Total Unrealized Gains (1) Amortization of Postretirement Benefit (1) Gain (Loss) on Foreign Currency (1) Credit Risk Changes of Fair Value Option Liabilities (1) (2) Total Beginning Balance $ (54) $ 6 $ (168) $ (1) $ (217) $ 49 $ 4 $ (123) $ (1) $ (70) Other comprehensive income (loss) before reclassifications (15) — 21 — 6 (67) — (55) — (122) Amounts reclassified from accumulated other comprehensive income (loss) 3 — — — 2 (5) — — 1 (4) Net current period other comprehensive income (loss) (13) — 21 — 8 (72) — (55) 1 (126) Ending Balance $ (67) $ 6 $ (147) $ (1) $ (209) $ (23) $ 4 $ (177) $ — $ (196) Six Months Ended June 30, 2023 Six Months Ended June 30, 2022 Unrealized Gains (1) Amortization of Postretirement Benefit (1) Gain (Loss) on Foreign Currency (1) Credit Risk Changes of Fair Value Option Liabilities (1) (2) Total Unrealized Gains (1) Amortization of Postretirement Benefit (1) Gain (Loss) on Foreign Currency (1) Credit Risk Changes of Fair Value Option Liabilities (1) (2) Total Beginning Balance $ (71) $ 3 $ (184) $ (1) $ (253) $ 154 $ 4 $ (100) $ (1) $ 58 Other comprehensive income before reclassifications (1) 3 37 — 39 (171) — (78) — (249) Amounts reclassified from accumulated other comprehensive income 6 (1) — — 5 (6) — — 1 (5) Net current period other comprehensive income 5 2 37 — 44 (177) — (78) 1 (254) Ending Balance $ (67) $ 6 $ (147) $ (1) $ (209) $ (23) $ 4 $ (177) $ — $ (196) (1) All amounts are net of tax and noncontrolling interest. Amounts in parentheses indicate reductions to Accumulated Other Comprehensive Income. (2) Represents the changes in fair value attributable to instrument-specific credit risk of liabilities for which the fair value option is elected. The following table details the significant amounts reclassified from each component of accumulated other comprehensive income, shown in the above rollforward tables, for the affected periods: Details about Accumulated Amount Reclassified from Affected Line Item in the Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Unrealized Gains (Losses) on Available-for-Sale Securities $ 3 $ (7) $ 8 $ (8) Net realized investment gains (losses) (1) 2 (2) 2 Provision for income taxes $ 3 $ (5) $ 6 $ (6) Net of tax and noncontrolling interest Amortization of Postretirement Benefit Prior service cost $ — $ — $ — $ — Other income Actuarial (losses) — — — — Other income — — (1) — Total before tax — — — — Provision for income taxes $ — $ — $ (1) $ — Net of tax and noncontrolling interest Credit Risk Changes of Fair Value Option Liabilities $ (1) $ 1 $ — $ 1 Credit risk changes of fair value option liabilities — — — — Provision for income taxes $ — $ 1 $ — $ 1 Net of tax and noncontrolling interest Total reclassifications for the period $ 2 $ (4) $ 5 $ (5) Net of tax and noncontrolling interest

Net Income Per Share

Net Income Per Share	6 Months Ended
Net Income Per Share	Jun. 30, 2023
Earnings Per Share [Abstract]
Net Income Per Share	12. NET INCOME PER SHARE As of June 30, 2023, 45,303,998 shares of AFG's common stock (par value $0.01) were issued and outstanding. Common shares outstanding increased by 330,241 during the six months ended June 30, 2023, primarily due settlements of employee restricted and performance stock units, partially offset by common stock repurchased under an approved share repurchase program. As of April 30, 2023, all of AFG's outstanding warrants expired without being exercised. Earnings Per Share Calculation The numerator of the basic and diluted earnings per share computation represents net income (loss) attributable to common stockholders adjusted by the retained earnings impact of the noncontrolling adjustment to redemption value under ASC 480. The redemption value adjustment is further described in the Redeemable Noncontrolling Interest section of Note 2. Basis of Presentation and Significant Accounting Policies . The following table provides a reconciliation of net income attributable to common stockholders to the numerator in the basic and diluted earnings per share calculation, together with the resulting earnings per share amounts: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Net income (loss) attributable to common stockholders $ (13) $ 5 $ (47) 7 Adjustment to redemption value (ASC 480) — — — — Numerator of basic and diluted EPS $ (13) $ 5 $ (47) 7 Per Share: Basic $ (0.29) $ 0.11 $ (1.02) $ 0.15 Diluted $ (0.29) $ 0.11 $ (1.02) $ 0.15 The denominator of the basic earnings per share computation represents the weighted average common shares outstanding plus vested restricted stock units (together, "Basic Weighted Average Shares Outstanding"). The denominator of diluted earnings per share adjusts the Basic Weighted Average Shares Outstanding for all potential dilutive common shares outstanding during the period. All potential dilutive common shares outstanding consider common stock deliverable pursuant to warrants, unvested restricted stock units and performance stock units granted under existing compensation plans. The following table provides a reconciliation of the weighted average shares denominator used for basic net income per share to the denominator used for diluted net income per share: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Basic weighted average shares outstanding denominator 45,757,234 45,519,093 45,661,288 46,121,927 Effect of potential dilutive shares : Warrants — — — — Restricted stock units — 82,128 — 81,411 Performance stock units (1) — 84,128 — 107,349 Diluted weighted average shares outstanding denominator 45,757,234 45,685,349 45,661,288 46,310,687 Anti-dilutive shares excluded from the above reconciliation: Warrants — 4,877,617 — 4,877,617 Restricted stock units 556,602 471,697 555,981 388,326 Performance stock units (1) 667,365 472,592 667,365 429,243

Income Taxes

Income Taxes	6 Months Ended
Income Taxes	Jun. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	13. INCOME TAXES AFG files a consolidated Federal income tax return with its subsidiaries. AFG and its subsidiaries also file separate or combined income tax returns in various states, local and foreign jurisdictions. The following are the major jurisdictions in which Ambac and its subsidiaries operate and the earliest tax years subject to examination: Jurisdiction Tax Year United States 2010 New York State 2013 New York City 2018 United Kingdom 2019 Italy 2018 In accordance with the Income Tax Topic of the ASC, a valuation allowance is recognized if, based on the weight of available evidence, it is more-likely-than-not that some, or all, of the deferred tax asset will not be realized. As a result of the risks and uncertainties associated with future operating results, management believes it is more likely than not that the Company will not generate sufficient U.S. federal, state and/or local taxable income to recover its deferred tax operating assets and therefore maintains a full valuation allowance. Consolidated Pretax Income (Loss) U.S. and foreign components of pre-tax income (loss) were as follows: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 U.S. $ (18) $ 10 $ (66) $ 10 Foreign 7 (4) 26 — Total $ (11) $ 6 $ (40) $ 9 Provision (Benefit) for Income Taxes The components of the provision for income taxes were as follows: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Current taxes U. S. federal $ 1 $ — $ 1 $ — U.S. state and local — — — — Foreign — 1 2 2 Total Current taxes 2 1 4 2 Deferred taxes Foreign — — 2 (1) Total Deferred taxes — — 2 (1) Provision for income taxes $ 2 $ 1 $ 6 $ 1

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	14. COMMITMENTS AND CONTINGENCIES The following commitments and contingencies provide an update of those discussed in Note 20: Commitments and Contingencies in the Notes to Consolidated Financial Statements included Part II, Item 8 in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 and in Note 14: Commitments and Contingencies in the Notes to the Unaudited Consolidated Financial Statements included in Part I, Item 1 in the Company's Quarterly Report on Form 10-Q for the quarter ended March 31, 2023, and should be read in conjunction with the complete descriptions provided in the aforementioned Form 10-K and Form 10-Q. Litigation Against Ambac Financial Oversight and Management Board for Puerto Rico, et al. v. Ambac Assurance Corporation, et al. (United States District Court, District of Puerto Rico, No. 19-ap-00363, filed May 20, 2019). On May 20, 2019, the Oversight Board, together with the Committee, as Plaintiffs, filed an adversary proceeding against certain parties that filed proofs of claim on account of bonds issued by PRHTA, including AAC. The complaint seeks declarations that the PRHTA bonds are only secured by revenues on deposit with the PRHTA fiscal agent and that PRHTA bondholders have no security interest in any other property of PRHTA or the Commonwealth, and in the alternative, to the extent such other security interests exist, the complaint seeks to avoid other security interests that holders of PRHTA bonds may have. On June 14, 2019, at the request of the Plaintiffs, the District Court stayed the case until September 1, 2019; on July 24, 2019, the District Court referred this matter to mediation and ordered it stayed during the pendency of such mediation. On December 19, 2019, the District Court ordered that this matter remain stayed pending further order of the District Court pursuant to the Oversight Board’s initiation of a separate adversary proceeding concerning PRHTA bonds (No. 20-ap-00005). The October 12, 2022 confirmation of the PRHTA POA, which has been affirmed by the First Circuit on appeal, resolved this litigation. AAC expects this case will be dismissed pursuant to PRHTA POA. Litigation Filed or Joined by Ambac Puerto Rico In re Financial Oversight and Management Board for Puerto Rico (United States District Court, District of Puerto Rico, No. 1:17- bk-03283) (appeals of the Commonwealth Plan). On January 18, 2022, the District Court entered an order confirming the Commonwealth Plan and entered its findings of fact and conclusions of law related thereto. Several parties filed notices of appeal of the District Court’s confirmation order to the First Circuit Court of Appeals, including a number of teachers’ unions (“the Teachers’ Unions”), the Oversight Board, certain individual creditors, a number of credit unions (“the Credit Unions”), and Suiza Dairy Corporation (“Suiza”). The First Circuit denied the appeals of the Oversight Board, the Teachers’ Unions, the individual creditors, and the Credit Unions and affirmed the order approving the Commonwealth Plan in each. Briefing in the Suiza appeal is complete; the First Circuit has not yet resolved the appeal. In re Financial Oversight and Management Board for Puerto Rico (United States District Court, District of Puerto Rico, No. 1:17- bk-03567) (appeal of the PRHTA POA). On October 12, 2022, the District Court entered an order confirming the PRHTA POA and entered its findings of fact and conclusions of law related thereto. On October 24, 2022, a group of present and former employees of PRHTA (“the Vazquez-Velazquez Group”) appealed the PRHTA POA confirmation order. On July 12, 2023, the First Circuit denied the appeal and affirmed the PRHTA POA confirmation order. On July 24, 2023, the Vazquez-Velazquez Group filed a petition for panel rehearing in the First Circuit. On July 24, 2023, the Vazquez-Velazquez Group filed a petition for panel rehearing in the First Circuit. Student Loans Exposure CFPB v. Nat’l Collegiate Master Student Loan Trust (United States District Court, District of Delaware, Case No. 1:17-cv-01323, filed September 18, 2017). The Third Circuit heard oral argument in the matter on May 17, 2023. RMBS Litigation Ambac Assurance Corporation v. U.S. Bank National Association (United States District Court, Southern District of New York, Docket No. 17-cv-02614, filed April 11, 2017). On October 18, 2022, the Court set a schedule for additional summary judgment

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2023
Accounting Policies [Abstract]
Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block]	Consolidation: The consolidated financial statements include the accounts of AFG and all other entities in which AFG (directly or through its subsidiaries) has a controlling financial interest, including variable interest entities (“VIEs”) for which AFG or an AFG subsidiary is deemed the primary beneficiary in accordance with the Consolidation Topic of the Accounting Standards Codification ("ASC"). All significant intercompany balances have been eliminated. See Note 9. Variable Interest Entities
Basis of Presentation and Significant Accounting Policies [Text Block]	Basis of Presentation: The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial reporting and with the instructions to Form 10-Q and Article 10 of
Foreign Currency Transactions and Translations Policy [Policy Text Block]	Foreign Currency:The impact of non-functional currency transactions and the remeasurement of non-functional currency assets and liabilities into the respective subsidiaries' functional currency (collectively "foreign currency transactions gains/(losses)") are $(3) and $7 for the six months ended June 30, 2023 and 2022, respectively. Foreign currency transactions gains/(losses) are primarily the result of remeasuring Ambac UK's assets and liabilities denominated in currencies (primarily the U.S. dollar and the Euro) other than its functional currency (the British Pound Sterling).
Noncontrolling Interest Disclosure	Redeemable Noncontrolling Interest: The All Trans, Capacity Marine and Xchange acquisitions, further described in the in the Notes to Consolidated Financial Statements included in Part II, Item 8 in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, resulted in 85%, 80% and 80%, respectively, ownership of the acquired entities by Ambac. Under the terms of the acquisition agreements, Ambac has call options to purchase the remaining 15%, 20% and 20%, respectively, from the minority owners (i.e., noncontrolling interests) and the minority owners have put options to sell the remaining 15%, 20% and 20%, respectively, to Ambac. Because the exercise of the put options are outside the control of Ambac, in accordance with the Distinguishing Liabilities from Equity Topic of the ASC, Ambac reports redeemable noncontrolling interests in the mezzanine section of its consolidated balance sheet. The redeemable noncontrolling interest is remeasured each period as the greater of: i. the carrying value under ASC 810, which attributes a portion of consolidated net income (loss) to the redeemable noncontrolling interest, and ii. the redemption value of the put option under ASC 480 as if it were exercisable at the end of the reporting period. Any increase (decrease) in the carrying amount of the redeemable noncontrolling interest as a result of adjusting to the redemption value of the put option is recorded as an offset to retained earnings. The impact of such differences on earnings per share are presented in Note 12. Net Income Per Share . Following is a rollforward of redeemable noncontrolling interest. Six Months Ended June 30, 2023 2022 Beginning balance $ 20 $ 18 Net income attributable to redeemable noncontrolling interest (ASC 810) — — Adjustment to redemption value (ASC 480) — — Ending balance $ 20 $ 18
Reclassifications	Reclassifications and Rounding 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.
New Accounting Pronouncements, Policy [Policy Text Block]	Adopted Accounting Standards: There have been no new accounting standards adopted during 2023. Future Application of Accounting Standards:
Noncontrolling Interest Policy	Redeemable Noncontrolling Interest: The All Trans, Capacity Marine and Xchange acquisitions, further described in the in the Notes to Consolidated Financial Statements included in Part II, Item 8 in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, resulted in 85%, 80% and 80%, respectively, ownership of the acquired entities by Ambac. Under the terms of the acquisition agreements, Ambac has call options to purchase the remaining 15%, 20% and 20%, respectively, from the minority owners (i.e., noncontrolling interests) and the minority owners have put options to sell the remaining 15%, 20% and 20%, respectively, to Ambac. Because the exercise of the put options are outside the control of Ambac, in accordance with the Distinguishing Liabilities from Equity Topic of the ASC, Ambac reports redeemable noncontrolling interests in the mezzanine section of its consolidated balance sheet. The redeemable noncontrolling interest is remeasured each period as the greater of: i. the carrying value under ASC 810, which attributes a portion of consolidated net income (loss) to the redeemable noncontrolling interest, and ii. the redemption value of the put option under ASC 480 as if it were exercisable at the end of the reporting period. Any increase (decrease) in the carrying amount of the redeemable noncontrolling interest as a result of adjusting to the redemption value of the put option is recorded as an offset to retained earnings. The impact of such differences on earnings per share are presented in Note 12. Net Income Per Share . Following is a rollforward of redeemable noncontrolling interest. Six Months Ended June 30, 2023 2022 Beginning balance $ 20 $ 18 Net income attributable to redeemable noncontrolling interest (ASC 810) — — Adjustment to redemption value (ASC 480) — — Ending balance $ 20 $ 18

Segment Reporting (Policies)

Segment Reporting (Policies)	6 Months Ended
Segment Reporting (Policies)	Jun. 30, 2023
Segment Reporting [Abstract]
Segment Reporting, Policy	The Company reports its results of operations in three segments: Legacy Financial Guarantee Insurance, Specialty Property and Casualty Insurance and Insurance Distribution, separate from Corporate and Other, which is consistent with the manner in which the Company's chief operating decision maker ("CODM") reviews the business to assess performance and allocate resources.

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies Supplemental Cash Flow Information (Tables)	6 Months Ended
	Jun. 30, 2023
Supplemental Cash Flow Elements [Abstract]
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]	Supplemental Disclosure of Cash Flow Information Six Months Ended June 30, 2023 2022 Cash paid during the period for: Income taxes $ 6 $ 5 Interest on long-term debt 50 32 Non-cash investing and financing activities: Exchange of investments in Puerto Rico bonds for new securities issued in the restructuring transactions $ — $ 185 Securities acquired (transferred) in transactions related to Puerto Rico restructurings (1) — June 30, 2023 2022 Reconciliation of cash, cash equivalents, and restricted cash reported within the Cash and cash equivalents $ 33 $ 32 Restricted cash 10 5 Variable Interest Entity restricted cash 266 2 Total cash, cash equivalents, and restricted cash shown on the Consolidated Statements of Cash Flows $ 309 $ 39
Redeemable Noncontrolling Interest	Following is a rollforward of redeemable noncontrolling interest. Six Months Ended June 30, 2023 2022 Beginning balance $ 20 $ 18 Net income attributable to redeemable noncontrolling interest (ASC 810) — — Adjustment to redemption value (ASC 480) — — Ending balance $ 20 $ 18

Segment Reporting (Tables)

Segment Reporting (Tables)	6 Months Ended
Segment Reporting (Tables)	Jun. 30, 2023
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following tables summarize the components of the Company’s total revenues and expenses, pretax income (loss) and total assets by reportable business segment. Information provided below for “Corporate and Other” primarily relates to the operations of AFG, which will include investment income on its investment portfolio and costs to maintain the operations of AFG, including public company reporting, capital management and business development costs for the acquisition and development of new business initiatives. Three Months Ended June 30, 2023 Three Months Ended June 30, 2022 Legacy Financial Guarantee Insurance Specialty Property & Casualty Insurance Insurance Distribution Corporate & Other Consoli-dated (2) Legacy Financial Guarantee Insurance Specialty Property & Casualty Insurance Insurance Distribution Corporate & Other Consoli-dated (2) Revenues: Net premiums earned $ 8 $ 8 $ 15 $ 11 $ 3 $ 14 Commission income $ 10 10 $ 6 6 Program fees 2 2 1 1 Net investment income (loss) 32 1 $ 2 35 (22) — — $ 1 (21) Net investment gains (losses), including impairments (3) — — (3) 7 — — 7 Net gains (losses) on derivative contracts 1 — — 28 — 1 29 Net realized gains on extinguishment of debt — — — 57 — 57 Other (1) 2 — — — 3 (6) — — — (6) Total revenues (2) 39 11 10 2 62 75 4 6 2 86 Expenses: Losses and loss adjustment expenses 2 6 7 (14) 2 (12) Amortization of deferred acquisition costs, net — 1 1 — — — Commission expenses 6 6 4 4 General and administrative expenses (3) 23 4 2 6 36 23 3 2 1 29 Depreciation expense (3) — — — — — — — — — — Intangible amortization 6 1 7 13 1 13 Interest expense 16 — — 16 45 45 Total expenses (2) 47 11 9 6 73 68 5 6 1 80 Pretax income (loss) $ (8) $ — $ 1 $ (4) $ (11) $ 7 $ (1) $ — $ 1 $ 6 Total assets (2) $ 7,376 $ 395 $ 137 $ 225 $ 8,132 $ 9,579 $ 229 $ 94 $ 159 $ 10,061 Six Months Ended June 30, 2023 Six Months Ended June 30, 2022 Legacy Financial Guarantee Insurance Specialty Property & Casualty Insurance Insurance Distribution Corporate & Other Consoli-dated (2) Legacy Financial Guarantee Insurance Specialty Property & Casualty Insurance Insurance Distribution Corporate & Other Consoli-dated (2) Revenues: Net premiums earned $ 14 $ 15 $ 29 24 4 28 Commission income 25 25 15 15 Program fees 4 4 1 1 Net investment income (loss) 63 2 4 69 (18) 1 1 (16) Net investment gains (losses), including impairments (8) — — (8) 17 — — 17 Net gains (losses) on derivative contracts (3) — — (3) 85 — 1 86 Net realized gains on extinguishment of debt — — 57 — 57 Other (1) 4 — — — 4 18 — — — 18 Total revenues (2) 71 20 25 4 120 184 5 15 2 206 Expenses: Losses and loss adjustment expenses 15 10 25 9 3 12 Amortization of deferred acquisition costs, net — 3 3 — — — Commission expenses 14 14 8 8 General and administrative expenses (3) 52 8 5 7 72 44 6 3 4 58 Depreciation expense (3) 1 — — — 1 1 — — — 1 Intangible amortization 11 2 13 26 1 28 Interest expense $ 32 $ 32 $ 89 $ 89 Total expenses (2) 111 21 20 8 160 170 9 13 4 197 Pretax income (loss) (40) (1) 4 (3) (40) 13 (4) 2 (3) 9 (1) Other revenues include the following line item on the Consolidated Statements of Total Comprehensive Income: Income (loss) on variable interest entities and other income. (2) Inter-segment revenues and inter-segment pre-tax income (loss) amounts are insignificant and are not presented separately. Total assets noted in the Corporate and Other Column is net of AFG's investment in surplus notes issued by the Legacy Financial Guarantee Segment with fair values of $— and $61 at June 30, 2023 and 2022. (3) The Consolidated Statements of Comprehensive Income presents the sum of these items as General & Administrative Expenses.

Investments (Tables)

Investments (Tables)	6 Months Ended
Investments (Tables)	Jun. 30, 2023
Investments, Debt and Equity Securities [Abstract]
Summary of Amortized Cost and Estimated Fair Value of Available-for-Sale Investments, Excluding VIE Investments Held by Successor Ambac, by Contractual Maturity	The amortized cost and estimated fair value of available-for-sale investments, excluding VIE investments, at June 30, 2023, by contractual maturity, were as follows: Amortized Estimated Due in one year or less $ 464 $ 463 Due after one year through five years 554 518 Due after five years through ten years 291 257 Due after ten years 62 54 1,371 1,292 Residential mortgage-backed securities 230 238 Commercial mortgage-backed securities 16 16 Collateralized debt obligations 140 138 Other asset-backed securities 275 268 Total $ 2,033 $ 1,953
Summary of Gross Unrealized Losses and Fair Values of Ambac's Available-for-Sale Investments	The following table shows gross unrealized losses and fair values of Ambac’s available-for-sale investments, excluding VIE investments, which at June 30, 2023 and December 31, 2022, did not have an allowance for credit losses under the CECL standard. This information is aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position, at June 30, 2023 and December 31, 2022: June 30, 2023 December 31, 2022 Less Than 12 Months 12 Months or More Total Less Than 12 Months 12 Months or More Total Fair Gross Fair Gross Fair Gross Fair Gross Fair Gross Fair Gross Fixed maturity securities: Municipal obligations $ 22 $ — $ 16 $ 2 $ 38 $ 2 $ 21 $ 1 $ 7 $ 1 $ 28 $ 2 Corporate obligations 209 9 447 53 656 62 280 21 279 42 559 63 Foreign obligations 36 2 47 9 83 11 27 2 47 7 73 9 U.S. government obligations 27 2 40 2 66 4 40 3 19 1 58 4 Residential mortgage-backed securities 74 2 91 15 165 17 132 19 — — 132 19 Commercial mortgage-backed securities 15 — — — 15 — 3 — — — 3 — Collateralized debt obligations — — 117 3 117 3 90 3 36 1 126 4 Other asset-backed securities 173 9 6 1 179 10 198 4 5 1 203 5 556 24 764 85 1,319 109 791 53 392 53 1,183 106 Short-term 37 — — — 37 — 78 — 8 — 86 — Total temporarily impaired securities $ 593 $ 24 $ 764 $ 85 $ 1,357 $ 109 $ 869 $ 53 $ 400 $ 53 $ 1,269 $ 106
Summary of Amounts Included in Net Realized (Losses) Gains and Other-Than-Temporary Impairments	The following table details amounts included in net investment gains (losses) and impairments included in earnings for the affected periods: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Gross realized gains on securities $ — $ — $ 1 $ 23 Gross realized losses on securities (2) (2) (3) (16) Foreign exchange gains (losses) (2) 8 (4) 11 Credit impairments — — (1) — Intent / requirement to sell impairments — — — — Net investment gains (losses), including impairments $ (3) $ 7 $ (8) $ 17
Summary of Fair Value, Including Financial Guarantee, and Weighted-Average Underlying Rating, Excluding Financial Guarantee, of Insured Securities	The following table represents the fair value and weighted-average underlying rating of insured securities in Ambac's investment portfolio at June 30, 2023 and December 31, 2022, respectively: Municipal Mortgage Total Weighted (1) June 30, 2023: $ 9 $ 436 $ 446 B- December 31, 2022: $ 10 $ 394 $ 403 B (1) Ratings are based on the lower of Standard & Poor’s or Moody’s rating. If unavailable, Ambac’s internal rating is used.
Equity Method Investments [Table Text Block]	In addition to these investments, Ambac has unfunded commitments of $52 to private credit and private equity funds at June 30, 2023. Fair Value Class of Funds June 30, December 31, 2022 Redemption Frequency Redemption Notice Period Hedge funds (1) $ 172 $ 186 quarterly or semi-annually 90 days Private credit (2) 85 84 quarterly if permitted 180 days if permitted High yields and leveraged loans (3) 74 80 daily 0 - 30 days Equity market investments (4) (10) 56 64 daily or quarterly 0 - 90 days Investment grade floating rate income (5) 41 63 weekly 0 days Private equity (6) 53 47 quarterly if permitted 90 days if permitted Real estate properties (7) 23 22 see footnote (7) see footnote (7) Convertible bonds (8)(10) 13 8 daily 0 days Insurance-linked investments (9) 1 1 see footnote (9) see footnote (9) Total equity investments in pooled funds $ 518 $ 556 (1) This class seeks to generate superior risk-adjusted returns through selective asset sourcing, active trading and hedging strategies across a range of asset types. (2) This class aims to obtain high long-term returns primarily through credit and preferred equity investments with low liquidity and defined term. (3) This class of funds includes investments in a range of instruments including high-yield bonds, leveraged loans, CLOs, ABS and floating rate notes to generate income and capital appreciation. (4) This class of funds aim to achieve long term growth through diversified exposure to global equity-markets. (5) This class of funds includes investments in high quality floating rate debt securities including ABS and corporate floating rate notes. (6) This class seeks to generate long-term capital appreciation through investments in private equity, equity-related and other instruments. (7) Investments consist of UK property to generate income and capital growth. In normal conditions, the fund allowed for quarterly redemptions with 10 days notice. The investment is currently restricted in connection with redemptions for a period of 12 months or longer. These restrictions are a result of redemption requests received by the fund in the calendar quarter or in aggregate in any rolling 12 month period, that exceed 10% or 15% of NAV of a portfolio, respectively. Ambac has requested full redemption of its interest in this fund. (8) This class seeks to generate total returns from portfolios focused primarily on convertible securities. (9) This class seeks to generate returns from insurance markets through investments in catastrophe bonds, life insurance and other insurance linked investments. This investment is restricted in connection with the unwind of certain insurance linked exposures. Ambac has redeemed its investment to the extent permitted by the fund.
Summary of Net Investment Income	Net investment income (loss) was comprised of the following for the affected periods: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Fixed maturity securities $ 19 $ 13 $ 35 $ 28 Short-term investments 5 1 10 1 Investment expense (1) (1) (3) (3) Securities available-for-sale and short-term 22 13 43 27 Fixed maturity securities - trading 4 (11) 5 (21) Other investments 9 (23) 22 (23) Total net investment income (loss) $ 35 $ (21) $ 69 $ (16)
Debt Securities, Available-for-Sale	The amortized cost and estimated fair value of available-for-sale investments, excluding VIE investments, at June 30, 2023 and December 31, 2022, were as follows: June 30, 2023: December 31, 2022: Amortized Allowance for Credit Losses (2) Gross Unrealized Estimated Amortized Allowance for Credit Losses Gross Unrealized Estimated Gains Losses Gains Losses Fixed maturity securities: Municipal obligations $ 64 $ — $ — $ 2 $ 63 $ 44 — $ — $ 2 $ 43 Corporate obligations 736 — — 62 674 659 — 1 63 598 Foreign obligations 94 — — 11 83 85 — — 9 76 U.S. government obligations 75 — — 4 71 68 — — 4 65 Residential mortgage-backed securities 230 1 26 17 238 230 — 28 19 238 Commercial mortgage-backed securities 16 — — — 16 15 — — — 15 Collateralized debt obligations 140 — — 3 138 141 — — 4 137 Other asset-backed securities (1) 275 — 3 10 268 227 — 2 5 224 1,632 1 30 109 1,552 1,469 — 31 106 1,395 Short-term 365 — — — 365 507 — — — 507 1,997 1 30 109 1,917 1,977 — 31 106 1,902 Fixed maturity securities pledged as collateral: Short-term 36 — — — 36 64 — — — 64 36 — — — 36 64 — — — 64 Total available-for-sale investments $ 2,033 $ 1 $ 30 $ 109 $ 1,953 $ 2,041 $ — $ 31 $ 106 $ 1,966 (1) Consists primarily of military housing and student loan securities. (2) For the three and six months ended June 30, 2023, the allowance for credit losses increased $0 and $1 on residential mortgage-backed securities on which credit losses were not previously recorded, respectively.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
Fair Value Measurements (Tables)	Jun. 30, 2023
Fair Value Disclosures [Abstract]
Summary of Carrying Amount and Fair Value of Ambac's Financial Assets and Liabilities	The following table sets forth the carrying amount and fair value of Ambac’s financial assets and liabilities as of June 30, 2023 and December 31, 2022, including the level within the fair value hierarchy at which fair value measurements are categorized. As required by the Fair Value Measurement Topic of the ASC, financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. June 30, 2023 December 31, 2022 Carrying Total Fair Fair Value Measurements Categorized as: Carrying Total Fair Fair Value Measurements Categorized as: Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Financial assets: Fixed maturity securities: Municipal obligations $ 90 $ 90 $ — $ 90 $ — $ 102 $ 102 $ — $ 102 $ — Corporate obligations 674 674 — 662 13 598 598 — 585 12 Foreign obligations 83 83 83 — — 76 76 76 — — U.S. government obligations 71 71 71 — — 65 65 65 — — Residential mortgage-backed securities 238 238 — 238 — 238 238 — 238 — Commercial mortgage-backed securities 16 16 — 16 — 15 15 — 15 — Collateralized debt obligations 138 138 — 138 — 137 137 — 137 — Other asset-backed securities 268 268 — 200 69 224 224 — 157 67 Fixed maturity securities, pledged as collateral: Short-term 36 36 36 — — 64 64 64 — — Short term investments 365 365 358 7 — 507 507 506 1 — Other investments (1) 530 518 69 — — 568 556 61 — — Cash, cash equivalents and restricted cash 43 43 43 — — 44 44 43 1 — Derivative assets: Interest rate swaps—asset position 25 25 — — 25 27 27 — 1 26 Warrants 1 1 — — 1 1 1 — — 1 Other assets-Loans 2 2 — — 2 10 10 — — 10 Variable interest entity assets: Fixed maturity securities: Corporate obligations, fair value option 1,952 1,952 — — 1,952 1,828 1,828 — — 1,828 Fixed maturity securities: Municipal obligation, trading — — — — — 43 43 — 43 — Fixed maturity securities: Municipal obligations, available-for-sale 104 104 — 104 — 96 96 — 96 — Restricted cash 266 266 266 — — 17 17 17 — — Loans 1,772 1,772 — — 1,772 1,829 1,829 — — 1,829 Derivative assets: Interest rate swaps—asset position 185 185 — 185 — 190 190 — 190 — Derivative assets: Currency swaps—asset position 39 39 — 39 — 49 49 — 49 — Total financial assets $ 6,899 $ 6,887 $ 926 $ 1,679 $ 3,833 $ 6,726 $ 6,715 $ 833 $ 1,615 $ 3,772 Financial liabilities: Long term debt, including accrued interest $ 951 $ 773 $ — $ 757 $ 16 $ 1,065 $ 878 $ — $ 864 $ 14 Derivative liabilities: Interest rate swaps—liability position 37 37 — 37 — 38 38 — 38 — Liabilities for net financial guarantees written (2) 311 727 — — 727 159 476 — — 476 Variable interest entity liabilities: Long-term debt 2,956 2,957 — 2,832 125 3,107 3,145 — 2,992 154 Derivative liabilities: Interest rate swaps—liability position 1,106 1,106 — 1,106 — 1,048 1,048 — 1,048 — Total financial liabilities $ 5,361 $ 5,600 $ — $ 4,732 $ 868 $ 5,418 $ 5,586 $ — $ 4,942 $ 644 (1) Excluded from the fair value measurement categories in the table above are investment funds of $449 and $494 as of June 30, 2023 and December 31, 2022, respectively, which are measured using NAV as a practical expedient. Also excluded from the fair value amounts in the table above are equity securities with a carrying value of $12 and $12 as of June 30, 2023 and December 31, 2022, respectively, that do not have readily determinable fair values and have carrying amounts determined using the measurement alternative. (2) The carrying value of net financial guarantees written includes financial guarantee amounts in the following balance sheet items: Premium receivables; Reinsurance recoverable on paid and unpaid losses; Deferred ceded premium; Subrogation recoverable; Insurance intangible asset; Unearned premiums; Loss and loss expense reserves; Ceded premiums payable, premiums taxes payable and other deferred fees recorded in Other liabilities.
Summary of Changes in Level 3 Fair Value Category	The following tables present the changes in the Level 3 fair value category for the periods presented in 2023 and 2022. Ambac classifies financial instruments in Level 3 of the fair value hierarchy when there is reliance on at least one significant unobservable input to the valuation model. In addition to these unobservable inputs, the valuation models for Level 3 financial instruments typically also rely on a number of inputs that are readily observable either directly or indirectly. Thus, the gains and losses presented below include changes in the fair value related to both observable and unobservable inputs. Level 3 - Financial Assets and Liabilities Accounted for at Fair Value VIE Assets Investments Derivatives Investments Loans Total Three Months Ended June 30, 2023: Balance, beginning of period $ 81 $ 31 $ 2,003 $ 1,856 $ 3,972 Total gains/(losses) realized and unrealized: Included in earnings — (5) (53) (66) (124) Included in other comprehensive income — — 14 50 64 Settlements — — (12) (69) (81) Balance, end of period $ 81 $ 25 $ 1,952 $ 1,772 $ 3,831 The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ — $ (5) $ (53) $ (66) $ (124) The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ — $ — $ 14 $ 50 $ 64 Three Months Ended June 30, 2022: Balance, beginning of period $ 86 $ 52 $ 3,131 $ 2,469 $ 5,738 Total gains/(losses) realized and unrealized: Included in earnings — (12) (365) (83) (460) Included in other comprehensive income (5) — (215) (174) (395) Settlements — (2) (18) (68) (88) Balance, end of period $ 81 $ 38 $ 2,533 $ 2,144 $ 4,795 The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ — $ (12) $ (365) $ (83) $ (460) The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ (5) $ — $ (215) $ (174) $ (395) Level 3 - Financial Assets and Liabilities Accounted for at Fair Value VIE Assets Investments Other Derivatives Investments Loans Total Six Months Ended June 30, 2023: Balance, beginning of period $ 79 $ — $ 26 $ 1,828 $ 1,829 $ 3,762 Total gains/(losses) realized and unrealized: Included in earnings 1 — — 80 (7) 73 Included in other comprehensive income 3 — — 57 92 152 Settlements (1) — — (12) (141) (155) Balance, end of period $ 81 $ — $ 25 $ 1,952 $ 1,772 $ 3,831 The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ 1 $ — $ — $ 80 $ (7) $ 73 The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ 3 $ — $ — $ 57 $ 92 $ 152 Six Months Ended June 30, 2022: Balance, beginning of period $ 91 $ — $ 70 $ 3,320 $ 2,718 $ 6,199 Total gains/(losses) realized and unrealized: Included in earnings 1 — (29) (458) (178) (664) Included in other comprehensive income (10) — — (311) (251) (572) Settlements (1) — (4) (18) (145) (168) Balance, end of period $ 81 $ — $ 38 $ 2,533 $ 2,144 $ 4,795 The amount of total gains/(losses) included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ 1 $ — $ (29) $ (458) $ (178) $ (664) The amount of total gains/(losses) included in other comprehensive income attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the reporting date $ (10) $ — $ — $ (311) $ (251) (572)
Summary of Gains and Losses (Realized and Unrealized) Relating to Level 3 Assets and Liabilities Included in Earnings	Gains and losses (realized and unrealized) relating to Level 3 assets and liabilities included in earnings for the affected periods are reported as follows: Three Months Ended June 30, 2023 Three Months Ended June 30, 2022 Net Net Gains Income (Loss) Other Net Net Gains Income (Loss) Other Total gains (losses) included in earnings for the period $ — $ (5) $ (119) $ — $ — $ (12) $ (448) $ — Changes in unrealized gains (losses) relating to financial instruments still held at the reporting date — (5) (119) — — (12) (448) — Six Months Ended June 30, 2023 Six Months Ended June 30, 2022 Net Net Gains Income (Loss) Other Net Net Gains Income (Loss) Other Total gains or losses included in earnings for the period $ 1 $ — $ 72 $ — $ 1 $ (29) $ (636) $ — Changes in unrealized gains or losses included in earnings relating to the assets and liabilities still held at the reporting date — — 72 — — (29) (636) —

Insurance Contracts (Tables)

Insurance Contracts (Tables)	6 Months Ended
Insurance Contracts (Tables)	Jun. 30, 2023	Jun. 30, 2022
Insurance [Line Items]
Schedule of Loss And Loss Expense Reserves And Subrogation Recoverable Table [Table Text Block]	Ambac’s loss and loss expense reserves (“loss reserves”) are based on management’s on-going review of the insured portfolio. Below are the components of the loss and loss expense reserves and the subrogation recoverable asset at June 30, 2023 and December 31, 2022: June 30, 2023 December 31, 2022 Specialty Property and Casualty Legacy Financial Guarantee Specialty Property and Casualty Legacy Financial Guarantee Present Value of Expected Net Cash Flows Present Value of Expected Net Cash Flows Balance Sheet Line Item Gross Loss Claims and Recoveries Unearned Gross Loss Gross Loss Claims and Recoveries Unearned Gross Loss Loss and loss expense reserves $ 130 $ 813 $ (50) $ (31) $ 863 $ 90 $ 787 $ (44) $ (28) $ 805 Subrogation recoverable — 2 (140) — (139) — 5 (276) — (271) Totals $ 130 $ 815 $ (190) $ (31) $ 724 $ 90 $ 791 $ (319) $ (28) $ 534
Premiums Receivable by Risk Classification Code [Table Text Block]	Below is the amortized cost basis of financial guarantee premium receivables by risk classification code and asset class as of June 30, 2023 and December 31, 2022: Surveillance Categories as of June 30, 2023 Surveillance Categories as of December 31, 2022 Type of Guaranteed Bond I IA II III IV Total I IA II III IV Total Public Finance: Housing revenue $ 136 $ 3 $ 5 $ — $ — $ 144 $ 140 $ 3 $ 5 $ — $ — $ 148 Other 2 — — — — 2 2 — — — — 2 Total Public Finance 138 3 5 — — 145 142 3 5 — — 150 Structured Finance: Mortgage-backed and home equity — — — — 10 11 — — — — 11 11 Student loan — — — 7 — 8 1 1 — 7 — 8 Other 4 — — — — 4 4 — — — — 4 Total Structured Finance 4 1 — 7 10 23 5 1 — 7 11 24 International: Sovereign/sub-sovereign 59 1 8 — — 69 49 7 — 9 — 64 Investor-owned and public utilities 18 — — — — 18 18 — — — — 18 Other 3 — — — — 3 2 — — — — 2 Total International 80 1 8 — — 89 70 7 — 9 — 85 Total (1) (2) $ 222 $ 5 $ 13 $ 7 $ 10 $ 257 $ 217 $ 10 $ 5 $ 16 $ 11 $ 259 (1) Excludes specialty property and casualty premium receivables of $23 and $16 at June 30, 2023 and December 31, 2022, respectively. (2) The underwriting origination dates for all policies included are greater than five years prior to the current reporting date.
Premium Receivable, Allowance for Credit Loss [Table Text Block]		Below is a rollforward of the premium receivable allowance for credit losses as of June 30, 2023 and 2022: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Beginning balance $ 5 $ 8 $ 5 $ 9 Current period provision (benefit) (1) (1) (1) (2) Write-offs of the allowance — (1) — (1) Recoveries of previously written-off amounts — — — — Ending balance (1) $ 5 $ 6 $ 5 $ 6 (1) At June 30, 2023 and 2022, $0 and $0 of premiums were past due.
Summary of Loss Reserve Roll-Forward, Net of Subrogation Recoverable and Reinsurance	Below is the loss and loss reserve expense roll-forward, net of subrogation recoverable and reinsurance, for the affected periods: Six Months Ended June 30, 2023 2022 Beginning gross loss and loss expense reserves $ 534 $ (522) Reinsurance recoverable 115 56 Beginning balance of net loss and loss expense reserves 419 (578) Losses and loss expenses (benefit): Current year 8 3 Prior years 18 9 Total (1) (2) 25 12 Loss and loss expenses paid (recovered): Current year 1 — Prior years (136) (158) Total (135) (157) Foreign exchange effect — (2) Ending net loss and loss expense reserves 580 (410) Impact of VIE consolidation — (292) Reinsurance recoverable (3) 144 55 Ending gross loss and loss expense reserves $ 724 $ (647) (1) Total losses and loss expenses (benefit) includes $(45) and $(14) for the six months ended June 30, 2023 and 2022, respectively, related to ceded reinsurance. (2) Ambac recorded 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) for the Legacy Financial Guarantee segment. The losses and loss expense incurred associated with changes in estimated R&W's for the six months ended June 30, 2023 and 2022, was $0 and $242, respectively. (3) 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 $5 and $0 as of June 30, 2023 and 2022, respectively, related to previously presented loss and loss expenses and subrogation.
Summary of Information Related to Policies Currently Included in Ambac's Loss Reserves or Subrogation Recoverable	The tables below summarize information related to policies currently included in Ambac’s loss and loss expense reserves or subrogation recoverable at June 30, 2023 and December 31, 2022, excluding consolidated VIEs. Gross par exposures include capital appreciation bonds which are reported at the par amount at the time of issuance of the insurance policy as opposed to the current accreted value of the bond. The weighted average risk-free rate used to discount loss reserves at June 30, 2023 and December 31, 2022,was 3.8% and 3.9%, respectively. Surveillance Categories as of June 30, 2023 I IA II III IV V Total Number of policies 32 9 12 12 93 5 163 Remaining weighted-average contract period (in years) (1) 8 13 12 14 12 7 12 Gross insured contractual payments outstanding: Principal $ 573 $ 633 $ 1,048 $ 408 $ 1,568 $ 28 $ 4,258 Interest 389 352 286 146 593 19 1,784 Total $ 962 $ 986 $ 1,334 $ 553 $ 2,161 $ 46 $ 6,042 Gross undiscounted claim liability $ 3 $ 12 $ 56 $ 409 $ 769 $ 46 $ 1,296 Discount, gross claim liability (1) (2) (9) (145) (320) (9) (486) Gross claim liability before all subrogation and before reinsurance 3 10 47 263 449 37 810 Less: Gross other subrogation (2) (15) (2) — (29) (200) (12) (257) Discount, other subrogation 3 — — 5 56 4 67 Discounted other subrogation, before reinsurance (12) (2) — (24) (144) (8) (190) Gross claim liability, net of all subrogation and discounts, before reinsurance (9) 7 47 239 305 29 620 Less: Unearned premium revenue (1) (6) (12) — (10) (1) (31) Plus: Loss expense reserves — 1 1 1 1 — 5 Gross loss and loss expense reserves $ (10) $ 2 $ 37 $ 239 $ 297 $ 28 $ 594 Reinsurance recoverable reported on Balance Sheet (3) $ 1 $ — $ 8 $ 20 $ 4 $ — $ 33 (1) Remaining weighted-average contract period is weighted based on projected gross claims over the lives of the respective policies. (2) Other subrogation represents subrogation related to excess spread and other contractual cash flows on public finance and structured finance transactions, including RMBS. (3) Reinsurance recoverable reported on the Balance Sheet includes reinsurance recoverables of $33 related to future loss and loss expenses and $0 related to presented loss and loss expenses and subrogation. Surveillance Categories as of December 31, 2022 I IA II III IV V Total Number of policies 37 6 9 12 93 5 162 Remaining weighted-average contract period (in years) (1) 7 19 14 14 12 7 14 Gross insured contractual payments outstanding: Principal $ 709 $ 200 $ 459 $ 1,000 $ 1,646 $ 34 $ 4,047 Interest 526 198 286 156 565 19 1,750 Total $ 1,235 $ 399 $ 745 $ 1,156 $ 2,210 $ 53 $ 5,797 Gross undiscounted claim liability $ 4 $ 4 $ 43 $ 446 $ 729 $ 53 $ 1,279 Discount, gross claim liability (1) (1) (7) (162) (316) (9) (496) Gross claim liability before all subrogation and before reinsurance 3 3 36 284 413 43 783 Less: Gross RMBS subrogation (2) — — — — (140) — (140) Discount, RMBS subrogation — — — — — — — Discounted RMBS subrogation, before reinsurance — — — — (140) — (140) Less: Gross other subrogation (3) (14) (4) — (31) (172) (12) (233) Discount, other subrogation 2 — — 5 42 4 54 Discounted other subrogation, before reinsurance (12) (3) — (26) (130) (8) (179) Gross claim liability, net of all subrogation and discounts, before reinsurance (9) — 36 258 143 35 464 Less: Unearned premium revenue (2) (2) (5) (8) (10) (1) (28) Plus: Loss expense reserves 1 1 — 2 4 — 8 Gross loss and loss expense reserves $ (10) $ (2) $ 32 $ 252 $ 137 $ 34 $ 444 Reinsurance recoverable reported on Balance Sheet (4) $ 1 $ — $ 8 $ 21 $ 3 $ — $ 33 (1) Remaining weighted-average contract period is weighted based on projected gross claims over the lives of the respective policies. (2) RMBS subrogation represents Ambac’s estimate of subrogation recoveries from RMBS transaction sponsors for R&W breaches. (3) Other subrogation represents subrogation related to excess spread and other contractual cash flows on public finance and structured finance transactions, including RMBS. (4) Reinsurance recoverable reported on the Balance Sheet includes reinsurance recoverables of $33 related to future loss and loss expenses and $0 related to presented loss and loss expenses and subrogation.
Summary of Rollforward of RMBS Subrogation, by Estimation Approach	On December 29, 2022, AAC entered into a Settlement Agreement and Release with Nomura Credit & Capital, Inc. ("Nomura") whereby the parties settled all RMBS litigation brought by AAC against Nomura and AAC received $140 on January 3, 2023, bringing to a close all of AAC's legacy litigation against RMBS sponsors.
Effects of Reinsurance	The effect of reinsurance on premiums written and earned was as follows: Three Months Ended June 30, 2023 2022 Written Earned Written Earned Direct $ 55 $ 52 $ 37 $ 30 Assumed — — — — Ceded 100 37 27 16 Net premiums $ (45) $ 15 $ 9 $ 14 Six Months Ended June 30, 2023 2022 Written Earned Written Earned Direct $ 115 $ 98 $ 67 $ 53 Assumed — — — — Ceded 142 69 46 24 Net premiums $ (27) $ 29 $ 21 $ 28 The following table summarizes net premiums earned by location of risk: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 United States $ 12 $ 10 $ 23 $ 20 United Kingdom 3 3 5 7 Other international 1 1 1 2 Total $ 15 $ 14 $ 29 $ 28
Premiums Receivable for Financial Guarantees	Below is the gross premium receivable roll-forward, net of the allowance for credit losses, for the affected periods: Six Months Ended June 30, 2023 2022 Beginning premium receivable $ 254 $ 320 Premium receipts (15) (22) Adjustments for changes in expected and contractual cash flows for contracts (1) 6 (5) Accretion of premium receivable discount for contracts 4 4 Changes to allowance for credit losses 1 3 Other adjustments (including foreign exchange) (2) 4 (12) Ending premium receivable (3) $ 253 $ 288 (1) Adjustments for changes in expected and contractual cash flows are primarily due to indexation offset by reductions in insured exposure as a result of early policy terminations and unscheduled principal paydowns. (2) Includes foreign exchange gains (losses) of $4 and $(11) for 2023 and 2022, respectively. (3) Premium receivable includes premiums to be received in foreign denominated currencies most notably in British Pounds and Euros. At June 30, 2023 and 2022, premium receivables include British Pounds of $76 (£60) and $91 (£74), respectively, and Euros of $14 (€12) and $15 (€14), respectively.
Financial Guarantee Insurance Contracts, Premium Received over Contract Period	The following table summarizes the future gross undiscounted premiums to be collected and future premiums earned, net of reinsurance at June 30, 2023: Future Premiums Collected (1) Future (2) Three months ended: September 30, 2023 $ 7 $ 4 December 31, 2023 5 4 Twelve months ended: December 31, 2024 27 16 December 31, 2025 26 15 December 31, 2026 25 15 December 31, 2027 24 14 Five years ended: December 31, 2032 100 58 December 31, 2037 63 33 December 31, 2042 29 11 December 31, 2047 14 4 December 31, 2052 4 1 December 31, 2057 — — Total $ 323 $ 176 (1) Future premiums to be collected are undiscounted, gross of allowance for credit losses, and are used to derive the discounted premium receivable asset recorded on Ambac's balance sheet. (2) Future premiums to be earned, net of reinsurance relate to the unearned premiums liability and deferred ceded premium asset recorded on Ambac’s balance sheet. The use of contractual lives for many bond types which do not have homogeneous pools of underlying collateral is required in the calculation of the premium receivable, as further described in Note 2. Basis of Presentation and Significant Accounting Policies in the Notes to Consolidated Financial Statements included in Ambac's Annual Report on Form 10-K for the year ended December 31, 2022. This results in a different premium receivable balance than if expected lives were considered. If installment paying policies are retired or prepay early, premiums reflected in the premium receivable asset and amounts reported in the above table for such policies may not be collected. Future premiums to be earned also considers the use of contractual lives for many bond types which do not have homogeneous pools of underlying collateral, which may result in different unearned premium than if expected lives were considered. If those bonds types are retired early, premium earnings may be negative in the period of call or refinancing.
Reinsurance Recoverable, Credit Quality Indicator	The following table sets forth our three most significant reinsurers by amount of reinsurance recoverable as of June 30, 2023. Reinsurers Type of Insurance Rating (1) Reinsurance Recoverable (2) Unsecured Recoverable (3) QBE Insurance Corporation Specialty P&C A $ 40 $ 40 General Reinsurance Company Specialty P&C A++ 51 37 Assured Guaranty Re Ltd. Financial AA 29 — All other reinsurers 29 10 Total recoverables $ 149 $ 87 (1) Represents financial strength ratings from S&P for financial guarantee reinsurers and AM Best for specialty P&C reinsurers. (2) Represents reinsurance recoverables on paid and unpaid losses. Unsecured amounts from QBE Insurance Corporation is also supported by an unlimited, uncapped indemnity from Enstar Holdings (US). (3) Reinsurance recoverables reduced by ceded premiums payables due to reinsurers, letters of credit, and collateral posted for the benefit of Ambac.

Derivative Instruments (Tables)

Derivative Instruments (Tables)	6 Months Ended
Derivative Instruments (Tables)	Jun. 30, 2023
Summary of Gross Fair Values of Individual Derivative Instruments	The following tables summarize the gross fair values of individual derivative instruments and the impact of legal rights of offset as reported in the Consolidated Balance Sheets as of June 30, 2023 and December 31, 2022: June 30, 2023 December 31, 2022 Gross Gross Net Amounts Gross Amount Net Gross Gross Net Amounts Gross Amount Net Derivative Assets: Interest rate swaps $ 25 $ — $ 25 $ — $ 25 $ 27 $ — $ 27 $ — $ 27 Warrants 1 — 1 — 1 1 — 1 — 1 Total non-VIE derivative assets $ 26 $ — $ 26 $ — $ 26 $ 28 $ — $ 27 $ — $ 27 Derivative Liabilities: Interest rate swaps $ 37 $ — $ 37 $ 36 $ — $ 38 $ — $ 38 $ 38 $ — Total non-VIE derivative liabilities $ 37 $ — $ 37 $ 36 $ — $ 38 $ — $ 38 $ 38 $ — Variable Interest Entities Derivative Assets: Interest rate swaps $ 185 $ — $ 185 $ 184 $ 1 $ 190 $ — $ 190 $ — $ 190 Currency swaps 39 — 39 39 — 49 — 49 — 49 Total VIE derivative assets $ 224 $ — $ 224 $ 223 $ 1 $ 239 $ — $ 239 $ — $ 239 Variable Interest Entities Derivative Liabilities: Interest rate swaps $ 1,106 $ — $ 1,106 $ — $ 1,106 $ 1,048 $ — $ 1,048 $ — $ 1,048 Total VIE derivative liabilities $ 1,106 $ — $ 1,106 $ — $ 1,106 $ 1,048 $ — $ 1,048 $ — $ 1,048
Summary of Location and Amount of Gains and Losses of Derivative Contracts	The following tables summarize the location and amount of gains and losses of derivative contracts in the Unaudited Consolidated Statements of Total Comprehensive Income (Loss) for the three and six months ended June 30, 2023 and 2022: Location of Gain (Loss) Amount of Gain (Loss) Recognized in Consolidated Statement of Total Comprehensive Income (Loss) Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Non-VIE derivatives: Interest rate swaps Net gains (losses) on derivative contracts 1 17 (3) 47 Warrants Net gains (losses) on derivative contracts — 1 — 1 Futures contracts Net gains (losses) on derivative contracts — 11 — 37 Total Non-VIE derivatives $ — $ 29 (3) 86 Variable Interest Entities: Currency swaps Income (loss) on variable interest entities $ (1) $ 14 (3) 20 Interest rate swaps Income (loss) on variable interest entities 97 264 (2) 269 Total Variable Interest Entities 96 278 (5) 289 Total derivative contracts $ 97 $ 307 $ (8) $ 376
Summary of Notional Amounts of AFS's Trading Derivative Products	As of June 30, 2023 and December 31, 2022, the notional amounts of AFS’s derivatives are as follows: Notional Type of Derivative June 30, December 31, Interest rate swaps—pay-fixed/receive-variable $ 142 $ 989 Interest rate swaps—receive-fixed/pay-variable 170 337
Variable Interest Entity, Primary Beneficiary [Member]
Summary of Notional Amounts of AFS's Trading Derivative Products	The notional amounts for VIE derivatives outstanding as of June 30, 2023 and December 31, 2022, were as follows: Notional Type of VIE Derivative June 30, December 31, Interest rate swaps—receive-fixed/pay-variable $ 1,655 $ 1,573 Interest rate swaps—pay-fixed/receive-variable 898 887 Currency swaps 163 176

Intangible Assets (Tables)

Intangible Assets (Tables)	6 Months Ended
Intangible Assets (Tables)	Jun. 30, 2023
Insurance Intangible Asset [Member]
Finite-Lived Intangible Assets [Line Items]
Schedule of Finite-Lived Intangible Assets	ntangible assets and accumulated amortization are included in the Consolidated Balance Sheets, as shown below. June 30, December 31, Finite-lived Intangible Assets: Insurance intangible: Gross carrying value $ 1,257 $ 1,247 Accumulated amortization 999 981 Net insurance intangible asset 258 266 Other intangibles: Gross carrying value 52 52 Accumulated amortization 7 6 Net other intangible assets 45 47 Total finite-lived intangible assets 303 312 Indefinite-lived Intangible Assets: Insurance licenses 14 14 Total intangible assets $ 317 $ 326

Special Purpose Entities, Inclu

Special Purpose Entities, Including Variable Interest Entities (Tables)	6 Months Ended
	Jun. 30, 2023
Variable Interest Entity [Line Items]
Components of VIE Gain (Loss) [Table Text Block]	The following schedule details the components of Income (loss) on variable interest entities for the affected periods: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Net change in fair value of VIE assets and liabilities reported under the fair value option $ — $ 1 $ 2 $ 1 Less: Credit risk changes of fair value option long-term debt reported through other comprehensive income (loss) 1 (1) 1 (2) Net change in fair value of VIE assets and liabilities reported in earnings under the fair value option — — 3 (1) Investment income (loss) 3 (1) 5 (5) Net realized investment gains (losses) on available-for-sale securities — — — 1 Interest expense on long-term debt carried at par less unamortized cost (3) (5) (8) (7) Gain (loss) from consolidating VIEs — — — 28 Income (loss) on variable interest entities $ — $ (6) $ (1) $ 15
Summary of Carrying Amount of Assets, Liabilities and Maximum Exposure to Loss of Ambac's Variable Interests in Non-Consolidated Variable Interest Entities	The following table displays the carrying amount of the assets, liabilities and maximum exposure to loss of Ambac’s variable interests in non-consolidated VIEs resulting from financial guarantee and derivative contracts by major underlying asset classes, as of June 30, 2023 and December 31, 2022: June 30, 2023: December 31, 2022: Carrying Value of Assets and Liabilities Carrying Value of Assets and Liabilities Maximum (1) Insurance (2) Insurance (3) Net Derivative (4) Maximum (1) Insurance (2) Insurance (3) Net Derivative (4) Global structured finance: Mortgage-backed—residential $ 2,475 $ 135 $ 434 $ — $ 2,559 $ 266 $ 400 $ — Other consumer asset-backed 595 5 226 — 652 6 225 — Other 432 2 2 — 430 2 2 1 Total global structured finance 3,503 142 662 — 3,642 274 628 1 Global public finance 17,981 218 215 — 17,997 216 212 — Total $ 21,484 $ 361 $ 877 $ — $ 21,639 $ 490 $ 840 $ 1 (1) Maximum exposure to loss represents the maximum future payments of principal and interest on insured obligations and derivative contracts. Ambac’s maximum exposure to loss does not include the benefit of any financial instruments (such as reinsurance or hedge contracts) that Ambac may utilize to mitigate the risks associated with these variable interests. (2) Insurance assets represent the amount included in “Premium receivables” and “Subrogation recoverable” for financial guarantee insurance contracts on Ambac’s Consolidated Balance Sheets. (3) Insurance liabilities represent the amount included in “Loss and loss expense reserves” and “Unearned premiums” for financial guarantee insurance contracts on Ambac’s Consolidated Balance Sheets. (4) Net derivative assets (liabilities) represent the fair value recognized on interest rate swaps on Ambac’s Consolidated Balance Sheets.
Schedule of Variable Interest Entities Assets and Liabilities [Table Text Block]	The following table summarizes the carrying values of assets and liabilities, along with other supplemental information related to FG VIEs that are consolidated as a result of financial guarantees of Ambac UK and AAC: June 30, 2023 December 31, 2022 Ambac UK Ambac Assurance Total VIEs Ambac UK Ambac Assurance Total VIEs ASSETS: Fixed maturity securities, at fair value: Corporate obligations, fair value option $ 1,952 $ — $ 1,952 $ 1,828 $ — $ 1,828 Municipal obligations, trading — — — — 43 43 Municipal obligations, available-for-sale (1) — 104 104 — 96 96 Total FG VIE fixed maturity securities, at fair value 1,952 104 2,056 1,828 139 1,967 Restricted cash 264 1 266 1 16 17 Loans, at fair value (2) 1,772 — 1,772 1,829 — 1,829 Derivative assets 224 — 224 239 — 239 Other assets — 2 2 — 2 2 Total FG VIE assets $ 4,213 $ 107 $ 4,320 $ 3,896 $ 157 $ 4,054 LIABILITIES: Long-term debt: Long-term debt, at fair value (3) $ 2,785 $ — $ 2,785 $ 2,788 $ — $ 2,788 Long-term debt, at par less unamortized discount — 171 171 — 319 319 Total long-term debt 2,785 171 2,956 2,788 319 3,107 Derivative liabilities 1,106 — 1,106 1,048 — 1,048 Cash collateral payable 263 — 263 — — — Other liabilities — 1 1 — 5 5 Total FG VIE liabilities $ 4,154 $ 172 $ 4,326 $ 3,836 $ 324 $ 4,160 Number of FG VIEs consolidated 4 4 8 5 4 9 (1) Available-for-sale FG VIE fixed maturity securities consist of municipal obligations with an amortized cost basis of $99 and $99 at June 30, 2023 and December 31, 2022, respectively. At June 30, 2023, there were $5 aggregate gross unrealized gains and $0 aggregated gross unrealized losses. At December 31, 2022, there were $1 aggregate gross unrealized gains and $(4) aggregated gross unrealized losses. All such securities had contractual maturities due after ten years as of June 30, 2023. (2) The unpaid principal balances of loan assets carried at fair value were $1,988 as of June 30, 2023 and $1,977 as of December 31, 2022. (3) The unpaid principal balances of long-term debt carried at fair value were $3,133 as of June 30, 2023 and $3,064 as of December 31, 2022.

Revenue Recognition and Defer_2

Revenue Recognition and Deferred Revenue (Tables)	6 Months Ended
Revenue Recognition and Deferred Revenue (Tables)	Jun. 30, 2023
Revenue Recognition and Deferred Revenue [Abstract]
Disaggregation of Revenue	The following table presents the Insurance Distribution business operations revenues recognized in accordance with the Revenue from Contracts with Customers Topic of the ASC disaggregated by policy type for the affected periods: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Employer Stop Loss $ 2 $ 1 $ 7 $ 5 Affinity Products 5 5 10 9 Commercial Auto 2 — 5 — Other 1 — 2 — Total $ 10 $ 6 $ 25 $ 15
Contract with Customer, Contract Asset, Contract Liability, and Receivable	The balances of contract assets and contract liabilities with customers were as follows: June 30, 2023 December 31, 2022 Premiums and commissions receivable $ 6 $ 7 Contract assets 9 5 Contract liabilities 1 1

Comprehensive Income (Tables)

Comprehensive Income (Tables)	6 Months Ended
Comprehensive Income (Tables)	Jun. 30, 2023
Equity [Abstract]
Schedule of Changes in Balances of Each Component of Accumulated Other Comprehensive Income	The following tables detail the changes in the balances of each component of accumulated other comprehensive income for the affected periods: Three Months Ended June 30, 2023: Three Months Ended June 30, 2022: Unrealized Gains (1) Amortization of Postretirement Benefit (1) Gain (Loss) on Foreign Currency (1) Credit Risk Changes of Fair Value Option Liabilities (1) (2) Total Unrealized Gains (1) Amortization of Postretirement Benefit (1) Gain (Loss) on Foreign Currency (1) Credit Risk Changes of Fair Value Option Liabilities (1) (2) Total Beginning Balance $ (54) $ 6 $ (168) $ (1) $ (217) $ 49 $ 4 $ (123) $ (1) $ (70) Other comprehensive income (loss) before reclassifications (15) — 21 — 6 (67) — (55) — (122) Amounts reclassified from accumulated other comprehensive income (loss) 3 — — — 2 (5) — — 1 (4) Net current period other comprehensive income (loss) (13) — 21 — 8 (72) — (55) 1 (126) Ending Balance $ (67) $ 6 $ (147) $ (1) $ (209) $ (23) $ 4 $ (177) $ — $ (196) Six Months Ended June 30, 2023 Six Months Ended June 30, 2022 Unrealized Gains (1) Amortization of Postretirement Benefit (1) Gain (Loss) on Foreign Currency (1) Credit Risk Changes of Fair Value Option Liabilities (1) (2) Total Unrealized Gains (1) Amortization of Postretirement Benefit (1) Gain (Loss) on Foreign Currency (1) Credit Risk Changes of Fair Value Option Liabilities (1) (2) Total Beginning Balance $ (71) $ 3 $ (184) $ (1) $ (253) $ 154 $ 4 $ (100) $ (1) $ 58 Other comprehensive income before reclassifications (1) 3 37 — 39 (171) — (78) — (249) Amounts reclassified from accumulated other comprehensive income 6 (1) — — 5 (6) — — 1 (5) Net current period other comprehensive income 5 2 37 — 44 (177) — (78) 1 (254) Ending Balance $ (67) $ 6 $ (147) $ (1) $ (209) $ (23) $ 4 $ (177) $ — $ (196) (1) All amounts are net of tax and noncontrolling interest. Amounts in parentheses indicate reductions to Accumulated Other Comprehensive Income. (2) Represents the changes in fair value attributable to instrument-specific credit risk of liabilities for which the fair value option is elected.
Schedule of Amounts Reclassed Out of Each Component of Accumulated Other Comprehensive Income	The following table details the significant amounts reclassified from each component of accumulated other comprehensive income, shown in the above rollforward tables, for the affected periods: Details about Accumulated Amount Reclassified from Affected Line Item in the Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Unrealized Gains (Losses) on Available-for-Sale Securities $ 3 $ (7) $ 8 $ (8) Net realized investment gains (losses) (1) 2 (2) 2 Provision for income taxes $ 3 $ (5) $ 6 $ (6) Net of tax and noncontrolling interest Amortization of Postretirement Benefit Prior service cost $ — $ — $ — $ — Other income Actuarial (losses) — — — — Other income — — (1) — Total before tax — — — — Provision for income taxes $ — $ — $ (1) $ — Net of tax and noncontrolling interest Credit Risk Changes of Fair Value Option Liabilities $ (1) $ 1 $ — $ 1 Credit risk changes of fair value option liabilities — — — — Provision for income taxes $ — $ 1 $ — $ 1 Net of tax and noncontrolling interest Total reclassifications for the period $ 2 $ (4) $ 5 $ (5) Net of tax and noncontrolling interest

Net Income Per Share (Tables)

Net Income Per Share (Tables)	6 Months Ended
Net Income Per Share (Tables)	Jun. 30, 2023
Earnings Per Share [Abstract]
Reconciliation of Common Shares Used for Basic and Diluted Earnings Per Share	The following table provides a reconciliation of the weighted average shares denominator used for basic net income per share to the denominator used for diluted net income per share: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Basic weighted average shares outstanding denominator 45,757,234 45,519,093 45,661,288 46,121,927 Effect of potential dilutive shares : Warrants — — — — Restricted stock units — 82,128 — 81,411 Performance stock units (1) — 84,128 — 107,349 Diluted weighted average shares outstanding denominator 45,757,234 45,685,349 45,661,288 46,310,687 Anti-dilutive shares excluded from the above reconciliation: Warrants — 4,877,617 — 4,877,617 Restricted stock units 556,602 471,697 555,981 388,326 Performance stock units (1) 667,365 472,592 667,365 429,243
Schedule of Earnings Per Share, Basic and Diluted	The following table provides a reconciliation of net income attributable to common stockholders to the numerator in the basic and diluted earnings per share calculation, together with the resulting earnings per share amounts: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Net income (loss) attributable to common stockholders $ (13) $ 5 $ (47) 7 Adjustment to redemption value (ASC 480) — — — — Numerator of basic and diluted EPS $ (13) $ 5 $ (47) 7 Per Share: Basic $ (0.29) $ 0.11 $ (1.02) $ 0.15 Diluted $ (0.29) $ 0.11 $ (1.02) $ 0.15

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
Income Taxes (Tables)	Jun. 30, 2023
Income Tax Disclosure [Abstract]
Major Jurisdictions	The following are the major jurisdictions in which Ambac and its subsidiaries operate and the earliest tax years subject to examination: Jurisdiction Tax Year United States 2010 New York State 2013 New York City 2018 United Kingdom 2019 Italy 2018
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]	U.S. and foreign components of pre-tax income (loss) were as follows: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 U.S. $ (18) $ 10 $ (66) $ 10 Foreign 7 (4) 26 — Total $ (11) $ 6 $ (40) $ 9
Schedule of Components of Income Tax Expense (Benefit)	The components of the provision for income taxes were as follows: Three Months Ended June 30, Six Months Ended June 30, 2023 2022 2023 2022 Current taxes U. S. federal $ 1 $ — $ 1 $ — U.S. state and local — — — — Foreign — 1 2 2 Total Current taxes 2 1 4 2 Deferred taxes Foreign — — 2 (1) Total Deferred taxes — — 2 (1) Provision for income taxes $ 2 $ 1 $ 6 $ 1

Background and Business Descr_2

Background and Business Description - Additional Information (Details)	6 Months Ended
	Jun. 30, 2023 level3FinancialInstruments USD ($)
Background And Basis Of Presentation [Line Items]
Entity Incorporation, Date of Incorporation	Apr. 29, 1991
Number of Admitted Carriers Owned \| $	5
Number of Reportable Segments \| level3FinancialInstruments	3
Background and Business Description	1. BACKGROUND AND BUSINESS DESCRIPTION The following description provides an update of Note 1. Background and Business Description in the Notes to the Consolidated Financial Statements included in Part II, Item 8 in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, and should be read in conjunction with the complete descriptions provided in the Form 10-K. Capitalized terms used, but not defined herein, and in the other footnotes to the Consolidated Financial Statements included in this Quarterly Report on Form 10-Q shall have the meanings ascribed thereto in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022. Ambac Financial Group, Inc. (“AFG”), headquartered in New York City, is a financial services holding company incorporated in the state of Delaware on April 29, 1991. References to “Ambac,” the “Company,” “we,” “our,” and “us” are to AFG and its subsidiaries, as the context requires. Ambac's principal businesses include: • Legacy Financial Guarantee Insurance — Ambac's financial guarantee business includes the activities of Ambac Assurance Corporation ("AAC") and its wholly owned subsidiaries, including Ambac Assurance UK Limited (“Ambac UK”) and Ambac Financial Services LLC ("AFS"). Both AAC and Ambac UK (the "Legacy Financial Guarantee Companies") have financial guarantee insurance portfolios that have been in runoff since 2008. AFS provided interest rate derivatives to financial guarantee customers and used derivatives to hedge interest rate risk in AAC's insurance and investment portfolios. As of June 30, 2023, AFS' only remaining derivative positions include a limited number of legacy customer swaps and their associated hedges. • Specialty Property & Casualty Insurance — Ambac's Specialty Property & Casualty Insurance program business. Currently includes five admitted carriers and an excess and surplus lines (“E&S” or “nonadmitted”) insurer (collectively, “Everspan”). Everspan carriers have an AM Best rating of 'A-' (Excellent) that was affirmed on June 13, 2023. • Insurance Distribution — Ambac's specialty property and casualty ("P&C") insurance distribution business, which could include Managing General Agents and Underwriters (collectively "MGAs"), insurance brokers, and other distribution businesses. Currently includes Xchange Benefits, LLC (“Xchange”), a P&C MGA specializing in accident and health products; All Trans Risk Solutions, LLC ("All Trans"), an MGA specializing in commercial automobile insurance for specific "for-hire" auto clauses; and Capacity Marine Corporation ("Capacity Marine"), a wholesale and retail brokerage and reinsurance intermediary specializing in marine and international risk. The Company reports these three business operations as segments; see Note 3. Segment Information for further information. Strategies to Enhance Shareholder Value The Company's primary goal is to maximize long-term shareholder value through the execution of targeted strategies for its (i) Specialty Property and Casualty Insurance and Insurance Distribution businesses and (ii) Legacy Financial Guarantee Insurance business. Specialty Property and Casualty Insurance and Insurance Distribution strategic priorities include: • Growing a Specialty Property and Casualty Insurance business which generates underwriting profits and an attractive return on capital from a diversified portfolio of commercial and personal liability risks accessed through program administrators. • Building an Insurance Distribution business based on deep domain knowledge in specialty and niche classes of risk which generate attractive margins at scale. This will be achieved through acquisitions, new business “de-novo” formation and incubation, and product expansion supported by a centralized technology led shared services offering. • Making opportunistic investments that are strategic to both the Specialty Property and Casualty Insurance and Insurance Distribution businesses. Legacy Financial Guarantee Insurance strategic priorities include: • Actively managing, de-risking and mitigating insured portfolio risk, and pursuing recovery of previously paid losses. • Improving operating efficiency and optimizing our asset and liability profile. • Exploring strategic options to further maximize value for AFG. The execution of Ambac’s strategy to increase the value of its investment in AAC is subject to the restrictions set forth in the Settlement Agreement, dated as of June 7, 2010, as amended (the "Settlement Agreement"), by and among AAC, Ambac Credit Products LLC ("ACP"), AFG and certain counterparties to credit default swaps with ACP that were guaranteed by AAC, as well as the Stipulation and Order among the Office of the Commissioner of Insurance for the State of Wisconsin (“OCI”), AFG and AAC that became effective on February 12, 2018, as amended (the “Stipulation and Order”), each of which requires OCI and, under certain circumstances, holders of surplus notes, to approve certain actions taken by or in respect of AAC. In exercising its approval rights, OCI will act for the benefit of policyholders, and will not take into account the interests of AFG. The Settlement Agreement limits certain activities of AAC and its subsidiaries, such as issuing indebtedness; engaging in mergers and similar transactions; disposing of assets; making restricted payments; creating or permitting liens; engaging in transactions with affiliates; modifying or creating tax sharing agreements; and taking certain actions with respect to surplus notes (among other restrictions and limitations). The Settlement Agreement includes certain allowances with respect to these activities and generally requires the approval of OCI and, in some cases, holders of surplus notes issued pursuant to the Settlement Agreement, for consents, waivers or amendments. The Stipulation and Order includes affirmative covenants, as well as restrictions on certain business activities and transactions, of AFG and AAC. The Stipulation and Order has no fixed term and may be terminated or modified only with the approval of OCI. OCI reserved the right to modify or terminate the Stipulation and Order in a manner consistent with the interests of policyholders, creditors and the public generally. The execution of Ambac’s strategy to increase the value of its investment in AAC may also be affected by a new capital framework being developed by OCI ("OCI's Runoff Capital Framework") to assist OCI with making decisions related to capital and liquidity management at AAC. OCI's Runoff Capital Framework is not yet complete and therefore we are not able to predict the results of such and what it may mean for our Legacy Financial Guarantee strategy, particularly as it relates to deleveraging AAC and distributing capital to AFG. Opportunities for remediating losses on poorly performing insured transactions also depend on market conditions, including the perception of AAC’s creditworthiness, the structure of the underlying risk and associated policy as well as other counterparty specific factors. AAC's ability to commute policies or purchase certain investments may also be limited by available liquidity.

Basis of Presentation and Sig_4

Basis of Presentation and Significant Accounting Policies FX gain (loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Foreign Currency Transaction Gain (Loss), before Tax			$ (3)	$ 7
Gain (Loss) on Investments [Member]
Foreign Currency Transaction Gain (Loss), before Tax	$ (2)	$ 8	$ (4)	$ 11

Basis of Presentation and Sig_5

Basis of Presentation and Significant Accounting Policies Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Stockholders' Equity Attributable to Noncontrolling Interest	$ 53,000,000		$ 53,000,000		$ 53,000,000
Preferred Stock, Shares Issued	0		0
Redeemable Noncontrolling Interest, Equity, Carrying Amount	$ 20,000,000	$ 18,000,000	$ 20,000,000	$ 18,000,000	20,000,000	$ 18,000,000
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest			0	0
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	0	0	(1,000,000)	0
Noncontrolling Interest, Change in Redemption Value	$ 0	$ 0	$ 0	$ 0
Number of Variable Interest Entities Consolidated During the Period	0	0	0	2
Temporary Equity, Accretion to Redemption Value, Adjustment			$ 0	$ 0
Xchange
Derivative [Line Items]
Redeemable Noncontrolling Interest, Equity, Carrying Amount					$ 20,000,000
Redeemable Noncontrolling Interest, Equity, Redemption Value	$ 20,000,000		$ 20,000,000
All Trans
Derivative [Line Items]
Business Combination, Redeemable Noncontrolling Percentage					15%
Business Acquisition, Percentage of Voting Interests Acquired					85%
Capacity Marine
Derivative [Line Items]
Business Combination, Redeemable Noncontrolling Percentage					20%
Business Acquisition, Percentage of Voting Interests Acquired					80%
Xchange
Derivative [Line Items]
Business Combination, Redeemable Noncontrolling Percentage					20%
Business Acquisition, Percentage of Voting Interests Acquired					80%

Basis of Presentation and Sig_6

Basis of Presentation and Significant Accounting Policies Supplemental Cash Flow information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Cash and Cash Equivalents, at Carrying Value	$ 33	$ 33	$ 32
Income Taxes Paid		6	5
Restricted Cash	10	10	5	$ 14
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	309	309	39	61	$ 23
Non Cash Exchange of Puerto Rico Bonds			185
Securities acquired (transferred) in transactions related to Puerto Rico restructurings	(1)
Long-term Debt [Member]
Interest Paid, Including Capitalized Interest, Operating and Investing Activities		50	32
Variable Interest Entity, Primary Beneficiary [Member]
Restricted Cash	$ 266	$ 266	$ 2	$ 17

Segment Reporting (Details)

Segment Reporting (Details) $ in Millions	3 Months Ended		6 Months Ended
Segment Reporting (Details) $ in Millions	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) level3FinancialInstruments	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Segment Reporting, Revenue Reconciling Item [Line Items]
Number of Reportable Segments \| level3FinancialInstruments			3
Revenues	$ 62	$ 86	$ 120	$ 206
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(11)	6	(40)	9
Provision for income taxes	2	1	6	1
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(13)	5	(46)	8
Premiums Earned, Net	15	14	29	28
Net Investment Income	35	(21)	69	(16)
Amortization of Intangible Assets	7	13	13	28
Interest Expense	16	45	32
Total assets	8,132	10,061	8,132	10,061	$ 7,973
Premiums Written, Net	(45)	9	(27)	21
Derivative, Gain (Loss) on Derivative, Net	0	29	(3)	86
Net realized gains on extinguishment of debt	0	57	0	57
Insurance Commissions and Fees	10	6	25	15
Losses and loss adjustment expenses	7	(12)	25	12
Other Cost and Expense, Operating	36	29	72	58
Insurance Commissions	6	4	14	8
Depreciation	0	0	1	1
Benefits, Losses and Expenses	73	80	160	197
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	0	0	(1)	0
Net income attributable to common shareholders	(13)	5	(47)	7
Realized Investment Gains (Losses)	(3)	7	(8)	17
Contractually Specified Servicing Fee, Late Fee, and Ancillary Fee Earned in Exchange for Servicing Financial Asset	2	1	4	1
Other income Items	3	(6)	4	18
Deferred Policy Acquisition Costs, Amortization Expense	1	0	3	0
Financial Guarantee
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	39	75	71	184
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(8)	7	(40)	13
Premiums Earned, Net	8	11	14	24
Net Investment Income	32	(22)	63	(18)
Amortization of Intangible Assets	6	13	11	26
Interest Expense	16	45	32	89
Total assets	7,376	9,579	7,376	9,579
Derivative, Gain (Loss) on Derivative, Net	1	28	(3)	85
Net realized gains on extinguishment of debt	0	57	0	57
Losses and loss adjustment expenses	2	(14)	15	9
Other Cost and Expense, Operating	23	23	52	44
Depreciation	0	0	1	1
Benefits, Losses and Expenses	47	68	111	170
Realized Investment Gains (Losses)	(3)	7	(8)	17
Other income Items	2	(6)	4	18
Deferred Policy Acquisition Costs, Amortization Expense	0	0	0	0
Specialty Property & Casualty Program
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	11	4	20	5
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	0	(1)	(1)	(4)
Premiums Earned, Net	8	3	15	4
Net Investment Income	1	0	2	1
Total assets	395	229	395	229
Losses and loss adjustment expenses	6	2	10	3
Other Cost and Expense, Operating	4	3	8	6
Depreciation	0	0	0	0
Benefits, Losses and Expenses	11	5	21	9
Managing General Agency Underwriter
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	10	6	25	15
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	1	0	4	2
Amortization of Intangible Assets	1	1	2	1
Total assets	137	94	137	94
Insurance Commissions and Fees	10	6	25	15
Other Cost and Expense, Operating	2	2	5	3
Insurance Commissions	6	4	14	8
Depreciation	0	0	0	0
Benefits, Losses and Expenses	9	6	20	13
Corporate and Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	2	2	4	2
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(4)	1	(3)	(3)
Net Investment Income	2	1	4	1
Total assets	225	159	225	159
Derivative, Gain (Loss) on Derivative, Net	0	1	0	1
Other Cost and Expense, Operating	6	1	7	4
Depreciation	0	0	0	0
Benefits, Losses and Expenses	6	1	8	4
Surplus Notes	0	61	0	61
Realized Investment Gains (Losses)	0	0	0	0
Other income Items	0	0	0	0
Property and Casualty, Commercial Insurance
Segment Reporting, Revenue Reconciling Item [Line Items]
Contractually Specified Servicing Fee, Late Fee, and Ancillary Fee Earned in Exchange for Servicing Financial Asset	2	1	4	1
Other income Items	0	0	0	0
Deferred Policy Acquisition Costs, Amortization Expense	1	0	3	0
Insurance Distribution
Segment Reporting, Revenue Reconciling Item [Line Items]
Other income Items	$ 0	$ 0	$ 0	$ 0

Investments - Summary of Amorti

Investments - Summary of Amortized Cost and Estimated Fair Value of Available-for-Sale Investments, Excluding VIE Investments (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 1	$ 1	$ 0	$ 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	30	30	31
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	24	24	53
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	764	764	400
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	85	85	53
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	109	109	106
Fixed maturity securities, at fair value	1,953	1,953
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Period Increase (Decrease)	0	1
Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	37	37	86
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	37	37	78
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0	8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0	0
Fixed maturity securities, at fair value	365	365	507
Fixed Income Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	1,319	1,319	1,183
Debt Securities, Available-for-sale, Allowance for Credit Loss	1	1	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	30	30	31
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	556	556	791
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	24	24	53
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	764	764	392
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	85	85	53
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	109	109	106
Fixed maturity securities, at fair value	1,552	1,552	1,395
Fixed Income Securities [Member] \| Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	38	38	28
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	22	22	21
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0	1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	16	16	7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2	2	1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	2	2	2
Fixed maturity securities, at fair value	63	63	43
Fixed Income Securities [Member] \| Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	656	656	559
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0	1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	209	209	280
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	9	9	21
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	447	447	279
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	53	53	42
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	62	62	63
Fixed maturity securities, at fair value	674	674	598
Fixed Income Securities [Member] \| Foreign Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	83	83	73
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	36	36	27
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2	2	2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	47	47	47
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	9	9	7
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	11	11	9
Fixed maturity securities, at fair value	83	83	76
Fixed Income Securities [Member] \| US Government Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	66	66	58
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	27	27	40
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2	2	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	40	40	19
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2	2	1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	4	4	4
Fixed maturity securities, at fair value	71	71	65
Fixed Income Securities [Member] \| Residential Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	165	165	132
Debt Securities, Available-for-sale, Allowance for Credit Loss	1	1	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	26	26	28
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	74	74	132
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2	2	19
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	91	91	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	15	15	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	17	17	19
Fixed maturity securities, at fair value	238	238	238
Fixed Income Securities [Member] \| Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	117	117	126
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	0	90
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	117	117	36
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	3	3	1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	3	3	4
Fixed maturity securities, at fair value	138	138	137
Fixed Income Securities [Member] \| Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	179	179	203
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	3	3	2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	173	173	198
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	9	9	4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	6	6	5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1	1	1
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	10	10	5
Fixed maturity securities, at fair value	268	268	224
Fixed Income Securities [Member] \| Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	15	15	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	15	15	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0	0
Fixed maturity securities, at fair value	16	16
Fixed Income Securities [Member] \| Collateralized Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0	0
Fixed maturity securities, at fair value	16	16	15
Fixed Income Investments And Other Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	1	1	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	30	30	31
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	109	109	106
Fixed maturity securities, at fair value	1,917	1,917	1,902
Collateral Pledged [Member] \| Fixed Income Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0	0
Fixed maturity securities, at fair value	36	36	64
Collateral Pledged [Member] \| Fixed Income Securities [Member] \| Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0	0
Fixed maturity securities, at fair value	36	36	64
Asset Pledged as Collateral [Member] \| Fixed Income Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 0	$ 0	$ 0

Investments - Summary of Amor_2

Investments - Summary of Amortized Cost and Estimated Fair Value of Available-for-Sale Investments, Excluding VIE Investments Held by Successor Ambac, by Contractual Maturity (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 2,033	$ 2,041
Fixed maturity securities, at fair value	1,953
Amortized Cost, Due in one year or less	464
Amortized Cost, Due after one year through five years	554
Amortized Cost, Due after five years through ten years	291
Amortized Cost, Due after ten years	62
Amortized Cost, Total	1,371
Estimated Fair Value, Due in one year or less	463
Estimated Fair Value, Due after one year through five years	518
Estimated Fair Value, Due after five years through ten years	257
Estimated Fair Value, Due after ten years	54
Estimated Fair Value due, Total	1,292
Fixed Income Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	1,632	1,469
Fixed maturity securities, at fair value	1,552	1,395
Fixed Income Securities [Member] \| Residential Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	230	230
Fixed maturity securities, at fair value	238	238
Fixed Income Securities [Member] \| Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	16
Fixed maturity securities, at fair value	16
Fixed Income Securities [Member] \| Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	140	141
Fixed maturity securities, at fair value	138	137
Fixed Income Securities [Member] \| Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	275	227
Fixed maturity securities, at fair value	$ 268	$ 224

Investments - Summary of Gross

Investments - Summary of Gross Unrealized Losses and Fair Values of Ambac's Available-for-Sale Investments (Details) $ in Millions	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 24	$ 53
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	764	400
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	85	53
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	109	106
Debt Securities , Available for sale, Continuous Unrealized Loss Position,	593	869
Debt Securities, Available for sale, Unrealized Loss Position, Including Pledged Securities	1,357	1,269
Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	37	78
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position	37	86
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 0	0
Ambac Insured Securities \| Parsed Fixed Income Securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	5,000
Fixed Income Investments And Other Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 109	106
Fixed Income Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	556	791
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	24	53
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	764	392
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	85	53
Debt Securities, Available-for-sale, Unrealized Loss Position	1,319	1,183
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	109	106
Fixed Income Securities [Member] \| Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	22	21
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	16	7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2	1
Debt Securities, Available-for-sale, Unrealized Loss Position	38	28
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	2	2
Fixed Income Securities [Member] \| Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	209	280
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	9	21
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	447	279
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	53	42
Debt Securities, Available-for-sale, Unrealized Loss Position	656	559
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 62	63
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	838,000
Fixed Income Securities [Member] \| Debt Security, Government, Non-US [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 36	27
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2	2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	47	47
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	9	7
Debt Securities, Available-for-sale, Unrealized Loss Position	83	73
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	11	9
Fixed Income Securities [Member] \| US Government Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	27	40
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	40	19
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2	1
Debt Securities, Available-for-sale, Unrealized Loss Position	66	58
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	4	4
Fixed Income Securities [Member] \| Residential Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	74	132
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2	19
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	91	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	15	0
Debt Securities, Available-for-sale, Unrealized Loss Position	165	132
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	17	19
Fixed Income Securities [Member] \| Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	15	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position	15	3
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Fixed Income Securities [Member] \| Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	90
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	117	36
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	3	1
Debt Securities, Available-for-sale, Unrealized Loss Position	117	126
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	3	4
Fixed Income Securities [Member] \| Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	173	198
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	9	4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	6	5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1	1
Debt Securities, Available-for-sale, Unrealized Loss Position	179	203
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 10	5
Debt Securities Available for Sale Unrealized Loss Measured as a Percent of Amortized Cost	5%
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	18,000
Fixed Income Securities [Member] \| Ambac Insured Securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 16
Debt Securities Available for Sale Unrealized Loss Measured as a Percent of Amortized Cost	13%
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	14,000
Collateral Pledged [Member] \| Fixed Income Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 0	0
Collateral Pledged [Member] \| Fixed Income Securities [Member] \| Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 0	$ 0

Investments - Additional Inform

Investments - Additional Information (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 1	$ 0	$ 0
Securities fair value	24	23
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 109	106
Average Percentage of Unrealized Loss Versus Amortized Cost for Below Investment Grade Securities	6%
Average Percentage of Unrealized Loss Versus Amortized Cost for Investment Grade Securities	9%
Investment Portfolio [Member]
Schedule of Investments [Line Items]
Fair Value of Cash and Securities Pledged to Derivative Counterparties	$ 36	64
Interest Rate Contract [Member]
Schedule of Investments [Line Items]
Other investments	74	80
Fixed Income Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	1	0
Debt Securities, Available-for-sale, Unrealized Loss Position	1,319	1,183
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	109	106
Fixed Income Securities [Member] \| Corporate Debt Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position	656	559
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	62	63
Fixed Income Securities [Member] \| Corporate Debt Securities [Member] \| External Credit Rating, Investment Grade
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	61
Fixed Income Securities [Member] \| Corporate Debt Securities [Member] \| External Credit Rating, Non Investment Grade [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	1
Fixed Income Securities [Member] \| Residential Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	1	0
Debt Securities, Available-for-sale, Unrealized Loss Position	165	132
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	17	19
Fixed Income Securities [Member] \| Asset-backed Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position	179	203
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	10	5
Reported Value Measurement [Member]
Schedule of Investments [Line Items]
Other investments	$ 69	$ 61

Investments - Summary of Amount

Investments - Summary of Amounts Included in Net Realized (Losses) Gains and Other-Than-Temporary Impairments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Investment [Line Items]
Foreign exchange (losses) gains			$ (3)	$ 7
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not to Sell before Recovery, Credit Loss, Previously Recorded, Expense (Reversal)	$ 0	$ 0	(1)	0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Sell before Recovery	0	0	0	0
Realized Investment Gains (Losses)	(3)	7	(8)	17
Fair Value of Securities Deposited in Connection wtih Letter of Credit	1		1		$ 1
Debt Securities, Available-for-sale, Realized Gain	0	0
Debt Securities, Available-for-sale, Realized Loss	2	2
Gross realized gains on securities			1	23
Available-for-sale Securities, Gross Realized Losses			(3)	(16)
Net realized (losses) gains			(8)	17
Gain (Loss) on Investments [Member]
Investment [Line Items]
Foreign exchange (losses) gains	$ (2)	$ 8	$ (4)	$ 11

Investments - Summary of Source

Investments - Summary of Sources of Collateral Received and Various Investment Agreement in which Collateral Pledged (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Investment [Line Items]
Fair Value Of Securities Deposited With Governmental Authorities	$ 24	$ 23
Fair Value of Securities Deposited in Connection wtih Letter of Credit	$ 1	1
Standard & Poor's, B Rating [Member]
Investment [Line Items]
Investment Owned, at Fair Value		403
Standard & Poor's, B Rating [Member] \| Municipal Bonds [Member]
Investment [Line Items]
Investment Owned, at Fair Value		10
Standard & Poor's, B Rating [Member] \| Mortgage And Other Asset Backed Securities [Member]
Investment [Line Items]
Investment Owned, at Fair Value		$ 394

Investments - Summary of Fair V

Investments - Summary of Fair Value, Including Financial Guarantee, and Weighted-Average Underlying Rating, Excluding Financial Guarantee, of Insured Securities (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Standard & Poor's, B Rating [Member]
Schedule of Investments [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		$ 403
Standard & Poor's, B- Rating [Member]
Schedule of Investments [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	$ 446
Municipal Bonds [Member] \| Standard & Poor's, B Rating [Member]
Schedule of Investments [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		10
Municipal Bonds [Member] \| Standard & Poor's, B- Rating [Member]
Schedule of Investments [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	9
Mortgage And Other Asset Backed Securities [Member] \| Standard & Poor's, B Rating [Member]
Schedule of Investments [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		$ 394
Mortgage And Other Asset Backed Securities [Member] \| Standard & Poor's, B- Rating [Member]
Schedule of Investments [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	$ 436

Investments - Summary of Fair_2

Investments - Summary of Fair Value, Including Financial Guarantee, and Weighted-Average Underlying Rating, Excluding Financial Guarantee, of Insured Securities (Phantom) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Investment [Line Items]
Net Realized and Unrealized Gain (Loss) on Trading Securities	$ 9	$ (29)
Investment expense	(1)	(1)	$ (3)	$ (3)
Interest and Dividend Income, Securities, Operating, Available-for-Sale	22	13	43	27
Net investment income (loss)	35	(21)	69	(16)
Gains (losses) on securities held as of reporting date [Member]
Investment [Line Items]
Net Realized and Unrealized Gain (Loss) on Trading Securities			16	(42)
Other Investments Income	2	(15)	6	(17)
Fixed Income Investments [Member]
Investment [Line Items]
Gross Investment Income, Operating	19	13	35	28
Short-Term [Member]
Investment [Line Items]
Gross Investment Income, Operating	5	1	10	1
Other Investments [Member]
Investment [Line Items]
Gross Investment Income, Operating	$ 9	$ (23)	$ 22	$ (23)

Investments - Summary of Net In

Investments - Summary of Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Investment [Line Items]
Equity Securities, FV-NI, Realized Gain (Loss)	$ 6	$ (14)
Interest and Dividend Income, Securities, Operating, Available-for-Sale	22	13	$ 43	$ 27
Short-term Investments [Member]
Investment [Line Items]
Gross Investment Income, Operating	5	1	10	1
Fixed Income Investments [Member]
Investment [Line Items]
Gross Investment Income, Operating	19	13	35	28
Fixed Income Securities, Trading
Investment [Line Items]
Gross Investment Income, Operating	$ 4	$ (11)	$ 5	$ (21)

Investments Investments - Equit

Investments Investments - Equity Investments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Equity Securities Excluded From Fair Value Table	$ 12		$ 12		$ 12
Equity Securities, FV-NI, Realized Gain (Loss)	6	$ (14)
Debt Securities, Available-for-sale, Allowance for Credit Loss	1	0	1	$ 0	0
Net Realized and Unrealized Gain (Loss) on Trading Securities	9	$ (29)
Real Estate [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	23		23		22
Hedge Funds, Multi-strategy [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	172		172		186
Interest Rate Contract [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	74		74		80
Illiquid Investments [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	85		85		84
Insurance Linked [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	1		1		1
Equity [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	56		56		64
Credit Index Product [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	41		41		63
Private Equity Funds [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	53		53		47
Equity investments in pooled funds [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	518		518		556
Equity Securities Excluded From Fair Value
Schedule of Equity Method Investments [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	0		0		0
Convertibles and Bonds with Warrants Attached
Schedule of Equity Method Investments [Line Items]
Other investments	13		13
Priced Through Pricing Vendors [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	69		69		61
Priced Through Pricing Vendors [Member] \| Equity [Member]
Schedule of Equity Method Investments [Line Items]
Other investments	56		56		53
Priced Through Pricing Vendors [Member] \| Convertibles and Bonds with Warrants Attached
Schedule of Equity Method Investments [Line Items]
Other investments	$ 13		13		$ 8
Gains (losses) on securities held as of reporting date [Member]
Schedule of Equity Method Investments [Line Items]
Equity Securities, FV-NI, Realized Gain (Loss)			10	(25)
Net Realized and Unrealized Gain (Loss) on Trading Securities			$ 16	$ (42)

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Carrying Amount and Fair Value of Ambac's Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	$ 1,953,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	1,000	$ 0	$ 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	30,000	31,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	109,000	106,000
Financial assets:
Derivative assets	26,000	28,000
Other assets	0
Long-term Debt	501,000	639,000
Financial liabilities:
Derivative liabilities	37,000	38,000
Equity Securities Excluded From Fair Value Table	12,000	12,000
Debt Securities, Available-for-sale, Amortized Cost	2,033,000	2,041,000
Debt Securities, Available-for-Sale, Current	1,953,000	1,966,000
Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	1,552,000	1,395,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	1,000	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	30,000	31,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	109,000	106,000
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	1,632,000	1,469,000
Fixed Income Investments And Other Investments [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	1,917,000	1,902,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	1,000	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	30,000	31,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	109,000	106,000
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	1,997,000	1,977,000
Commercial Mortgage Backed Securities [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	16,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	16,000
Short-term Investments [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	365,000	507,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	365,000	507,000
Asset-backed Securities [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	268,000	224,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	3,000	2,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	10,000	5,000
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	275,000	227,000
Collateralized Debt Obligations [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	138,000	137,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	3,000	4,000
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	140,000	141,000
Residential Mortgage-Backed Securities [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	238,000	238,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	1,000	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	26,000	28,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	17,000	19,000
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	230,000	230,000
US Government Debt Securities [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	71,000	65,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	4,000	4,000
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	75,000	68,000
Debt Security, Government, Non-US [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	83,000	76,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	11,000	9,000
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	94,000	85,000
Corporate Debt Securities [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	674,000	598,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	1,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	62,000	63,000
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	736,000	659,000
Municipal Bonds [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	63,000	43,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	2,000	2,000
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	64,000	44,000
Collateralized Mortgage Backed Securities [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	16,000	15,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	16,000	15,000
Total Fair Value [Member]
Financial assets:
Cash	43,000	44,000
Reported Value Measurement [Member]
Financial assets:
Other investments	69,000	61,000
Cash	43,000	44,000
Loans	2,000	10,000
Total financial assets	6,899,000	6,726,000
Financial liabilities:
Liabilities for net financial guarantees written	311,000	159,000
Long-term debt	951,000	1,065,000
Total financial liabilities	5,361,000	5,418,000
Reported Value Measurement [Member] \| Short-term Investments [Member]
Financial assets:
Short term investments	365,000	507,000
Reported Value Measurement [Member] \| Other Debt Obligations [Member]
Financial assets:
Other investments	530,000	568,000
Reported Value Measurement [Member] \| Interest Rate Swap [Member]
Financial liabilities:
Derivative liabilities	37,000	38,000
Reported Value Measurement [Member] \| Interest Rate Swap [Member] \| Other Assets [Member]
Financial assets:
Derivative assets	25,000	27,000
Reported Value Measurement [Member] \| Warrants [Member]
Financial assets:
Derivative assets	1,000	1,000
Level 1 [Member]
Financial assets:
Cash	43,000	43,000
Total financial assets	926,000	833,000
Financial liabilities:
Liabilities for net financial guarantees written	0	0
Long-term debt	0	0
Total financial liabilities	0	0
Level 1 [Member] \| Short-term Investments [Member]
Financial assets:
Short term investments	358,000	506,000
Level 1 [Member] \| Loans Receivable [Member]
Financial assets:
Loans	0	0
Level 1 [Member] \| Other Debt Obligations [Member]
Financial assets:
Other investments	69,000	61,000
Level 1 [Member] \| Interest Rate Swap [Member]
Financial liabilities:
Derivative liabilities	0	0
Level 1 [Member] \| Interest Rate Swap [Member] \| Other Assets [Member]
Financial assets:
Derivative assets	0	0
Level 1 [Member] \| Warrants [Member]
Financial assets:
Derivative assets	0	0
Level 2 [Member]
Financial assets:
Cash	0	1,000
Total financial assets	1,679,000	1,615,000
Financial liabilities:
Liabilities for net financial guarantees written	0	0
Long-term debt	757,000	864,000
Total financial liabilities	4,732,000	4,942,000
Level 2 [Member] \| Short-term Investments [Member]
Financial assets:
Short term investments	7,000	1,000
Level 2 [Member] \| Loans Receivable [Member]
Financial assets:
Loans	0	0
Level 2 [Member] \| Other Debt Obligations [Member]
Financial assets:
Other investments	0	0
Level 2 [Member] \| Interest Rate Swap [Member]
Financial liabilities:
Derivative liabilities	37,000	38,000
Level 2 [Member] \| Interest Rate Swap [Member] \| Other Assets [Member]
Financial assets:
Derivative assets	0	1,000
Level 2 [Member] \| Warrants [Member]
Financial assets:
Derivative assets	0	0
Level 3 [Member]
Financial assets:
Cash	0	0
Total financial assets	3,833,000	3,772,000
Financial liabilities:
Liabilities for net financial guarantees written	727,000	476,000
Long-term debt	16,000	14,000
Total financial liabilities	868,000	644,000
Level 3 [Member] \| Short-term Investments [Member]
Financial assets:
Short term investments	0	0
Level 3 [Member] \| Loans Receivable [Member]
Financial assets:
Loans	2,000	10,000
Level 3 [Member] \| Other Debt Obligations [Member]
Financial assets:
Other investments	0	0
Level 3 [Member] \| Interest Rate Swap [Member]
Financial liabilities:
Derivative liabilities	0	0
Level 3 [Member] \| Interest Rate Swap [Member] \| Other Assets [Member]
Financial assets:
Derivative assets	25,000	26,000
Level 3 [Member] \| Warrants [Member]
Financial assets:
Derivative assets	1,000	1,000
Commercial Mortgage Backed Securities [Member] \| Reported Value Measurement [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	16,000	15,000
Municipal Bonds [Member] \| Reported Value Measurement [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	90,000	102,000
Corporate Debt Securities [Member] \| Reported Value Measurement [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	674,000	598,000
Debt Security, Government, Non-US [Member] \| Reported Value Measurement [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	83,000	76,000
US Government Debt Securities [Member] \| Reported Value Measurement [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	71,000	65,000
Residential Mortgage-Backed Securities [Member] \| Reported Value Measurement [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	238,000	238,000
Collateralized Debt Obligations [Member] \| Reported Value Measurement [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	138,000	137,000
Asset-backed Securities [Member] \| Reported Value Measurement [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	268,000	224,000
Fair Value, Recurring [Member]
Financial assets:
Total financial assets	6,887,000	6,715,000
Financial liabilities:
Liabilities for net financial guarantees written	727,000	476,000
Long-term debt	773,000	878,000
Total financial liabilities	5,600,000	5,586,000
Fair Value, Recurring [Member] \| Commercial Mortgage Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	16,000	15,000
Fair Value, Recurring [Member] \| Short-term Investments [Member]
Financial assets:
Short term investments	365,000	507,000
Fair Value, Recurring [Member] \| Loans Receivable [Member]
Financial assets:
Loans	2,000	10,000
Fair Value, Recurring [Member] \| Other Debt Obligations [Member]
Financial assets:
Other investments	518,000	556,000
Fair Value, Recurring [Member] \| Asset-backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	268,000	224,000
Fair Value, Recurring [Member] \| Collateralized Debt Obligations [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	138,000	137,000
Fair Value, Recurring [Member] \| Residential Mortgage-Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	238,000	238,000
Fair Value, Recurring [Member] \| US Government Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	71,000	65,000
Fair Value, Recurring [Member] \| Debt Security, Government, Non-US [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	83,000	76,000
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	674,000	598,000
Fair Value, Recurring [Member] \| Municipal Bonds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	90,000	102,000
Fair Value, Recurring [Member] \| Interest Rate Swap [Member]
Financial liabilities:
Derivative liabilities	37,000	38,000
Fair Value, Recurring [Member] \| Interest Rate Swap [Member] \| Other Assets [Member]
Financial assets:
Derivative assets	25,000	27,000
Fair Value, Recurring [Member] \| Warrants [Member]
Financial assets:
Derivative assets	1,000	1,000
Fair Value, Recurring [Member] \| Level 1 [Member] \| Commercial Mortgage Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Fair Value, Recurring [Member] \| Level 1 [Member] \| Asset-backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Fair Value, Recurring [Member] \| Level 1 [Member] \| Collateralized Debt Obligations [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Fair Value, Recurring [Member] \| Level 1 [Member] \| Residential Mortgage-Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Fair Value, Recurring [Member] \| Level 1 [Member] \| US Government Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	71,000	65,000
Fair Value, Recurring [Member] \| Level 1 [Member] \| Debt Security, Government, Non-US [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	83,000	76,000
Fair Value, Recurring [Member] \| Level 1 [Member] \| Corporate Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Fair Value, Recurring [Member] \| Level 1 [Member] \| Municipal Bonds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Fair Value, Recurring [Member] \| Level 2 [Member] \| Commercial Mortgage Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	16,000	15,000
Fair Value, Recurring [Member] \| Level 2 [Member] \| Asset-backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	200,000	157,000
Fair Value, Recurring [Member] \| Level 2 [Member] \| Collateralized Debt Obligations [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	138,000	137,000
Fair Value, Recurring [Member] \| Level 2 [Member] \| Residential Mortgage-Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	238,000	238,000
Fair Value, Recurring [Member] \| Level 2 [Member] \| US Government Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Fair Value, Recurring [Member] \| Level 2 [Member] \| Debt Security, Government, Non-US [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Fair Value, Recurring [Member] \| Level 2 [Member] \| Corporate Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	662,000	585,000
Fair Value, Recurring [Member] \| Level 2 [Member] \| Municipal Bonds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	90,000	102,000
Fair Value, Recurring [Member] \| Level 3 [Member] \| Commercial Mortgage Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Fair Value, Recurring [Member] \| Level 3 [Member] \| Asset-backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	69,000	67,000
Fair Value, Recurring [Member] \| Level 3 [Member] \| Collateralized Debt Obligations [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Fair Value, Recurring [Member] \| Level 3 [Member] \| Residential Mortgage-Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Fair Value, Recurring [Member] \| Level 3 [Member] \| US Government Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Fair Value, Recurring [Member] \| Level 3 [Member] \| Debt Security, Government, Non-US [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Fair Value, Recurring [Member] \| Level 3 [Member] \| Corporate Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	13,000	12,000
Fair Value, Recurring [Member] \| Level 3 [Member] \| Municipal Bonds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Collateral Pledged [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	36,000	64,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Collateral Pledged [Member] \| Short-term Investments [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	36,000	64,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0	0
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	36,000	64,000
Collateral Pledged [Member] \| Short-term Investments [Member] \| Reported Value Measurement [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	36,000	64,000
Collateral Pledged [Member] \| Fair Value, Recurring [Member] \| Short-term Investments [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	36,000	64,000
Collateral Pledged [Member] \| Fair Value, Recurring [Member] \| Level 1 [Member] \| Short-term Investments [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	36,000	64,000
Collateral Pledged [Member] \| Fair Value, Recurring [Member] \| Level 2 [Member] \| Short-term Investments [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Collateral Pledged [Member] \| Fair Value, Recurring [Member] \| Level 3 [Member] \| Short-term Investments [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Asset Pledged as Collateral [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	36,000	64,000
Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	2,056,000	1,967,000
Financial assets:
Loans	1,772,000	1,829,000
Derivative assets	224,000	239,000
Long-term Debt	2,956,000	3,107,000
Financial liabilities:
Derivative liabilities	1,106,000	1,048,000
Long-term debt	2,785,000	2,788,000
Variable Interest Entity, Primary Beneficiary [Member] \| Corporate Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	1,952,000	1,828,000
Variable Interest Entity, Primary Beneficiary [Member] \| Municipal Bonds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	104,000	96,000
Financial liabilities:
Debt Securities, Available-for-sale, Amortized Cost	99,000	99,000
Variable Interest Entity, Primary Beneficiary [Member] \| US States and Political Subdivisions Debt Securities
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	43,000
Variable Interest Entity, Primary Beneficiary [Member] \| Reported Value Measurement [Member]
Financial assets:
Restricted Cash and Cash Equivalents, Current	266,000	17,000
Loans	1,772,000	1,829,000
Financial liabilities:
Long-term debt	2,956,000	3,107,000
Variable Interest Entity, Primary Beneficiary [Member] \| Reported Value Measurement [Member] \| Corporate Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	1,952,000	1,828,000
Variable Interest Entity, Primary Beneficiary [Member] \| Reported Value Measurement [Member] \| Municipal Bonds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	104,000		$ 96,000
Variable Interest Entity, Primary Beneficiary [Member] \| Reported Value Measurement [Member] \| Interest Rate Swap [Member]
Financial assets:
Derivative assets	185,000	190,000
Financial liabilities:
Derivative liabilities	1,106,000	1,048,000
Variable Interest Entity, Primary Beneficiary [Member] \| Reported Value Measurement [Member] \| Currency Swaps [Member]
Financial assets:
Derivative assets	39,000	49,000
Variable Interest Entity, Primary Beneficiary [Member] \| Reported Value Measurement [Member] \| US States and Political Subdivisions Debt Securities
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Debt Securities, Trading	0	43,000
Variable Interest Entity, Primary Beneficiary [Member] \| Level 1 [Member]
Financial assets:
Restricted Cash and Cash Equivalents, Current	266,000	17,000
Loans	0	0
Financial liabilities:
Long-term debt	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Level 1 [Member] \| Corporate Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Level 1 [Member] \| Municipal Bonds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Level 1 [Member] \| Interest Rate Swap [Member]
Financial assets:
Derivative assets	0	0
Financial liabilities:
Derivative liabilities	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Level 1 [Member] \| Currency Swaps [Member]
Financial assets:
Derivative assets	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Level 1 [Member] \| US States and Political Subdivisions Debt Securities
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Debt Securities, Trading	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Level 2 [Member]
Financial assets:
Restricted Cash and Cash Equivalents, Current	0	0
Loans	0	0
Financial liabilities:
Long-term debt	2,832,000	2,992,000
Variable Interest Entity, Primary Beneficiary [Member] \| Level 2 [Member] \| Corporate Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Level 2 [Member] \| Municipal Bonds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	104,000	96,000
Variable Interest Entity, Primary Beneficiary [Member] \| Level 2 [Member] \| Interest Rate Swap [Member]
Financial assets:
Derivative assets	185,000	190,000
Financial liabilities:
Derivative liabilities	1,106,000	1,048,000
Variable Interest Entity, Primary Beneficiary [Member] \| Level 2 [Member] \| Currency Swaps [Member]
Financial assets:
Derivative assets	39,000	49,000
Variable Interest Entity, Primary Beneficiary [Member] \| Level 2 [Member] \| US States and Political Subdivisions Debt Securities
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Debt Securities, Trading	0	43,000
Variable Interest Entity, Primary Beneficiary [Member] \| Level 3 [Member]
Financial assets:
Restricted Cash and Cash Equivalents, Current	0	0
Loans	1,772,000	1,829,000
Financial liabilities:
Long-term debt	125,000	154,000
Variable Interest Entity, Primary Beneficiary [Member] \| Level 3 [Member] \| Corporate Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	1,952,000	1,828,000
Variable Interest Entity, Primary Beneficiary [Member] \| Level 3 [Member] \| Municipal Bonds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Level 3 [Member] \| Interest Rate Swap [Member]
Financial assets:
Derivative assets	0	0
Financial liabilities:
Derivative liabilities	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Level 3 [Member] \| Currency Swaps [Member]
Financial assets:
Derivative assets	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Level 3 [Member] \| US States and Political Subdivisions Debt Securities
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Debt Securities, Trading	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Fair Value, Recurring [Member]
Financial assets:
Restricted Cash and Cash Equivalents, Current	266,000	17,000
Loans	1,772,000	1,829,000
Financial liabilities:
Long-term debt	2,957,000	3,145,000
Variable Interest Entity, Primary Beneficiary [Member] \| Fair Value, Recurring [Member] \| Corporate Debt Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	1,952,000	1,828,000
Variable Interest Entity, Primary Beneficiary [Member] \| Fair Value, Recurring [Member] \| Municipal Bonds [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fixed maturity securities, at fair value	104,000	96,000
Variable Interest Entity, Primary Beneficiary [Member] \| Fair Value, Recurring [Member] \| Interest Rate Swap [Member]
Financial assets:
Derivative assets	185,000	190,000
Financial liabilities:
Derivative liabilities	1,106,000	1,048,000
Variable Interest Entity, Primary Beneficiary [Member] \| Fair Value, Recurring [Member] \| Currency Swaps [Member]
Financial assets:
Derivative assets	39,000	49,000
Variable Interest Entity, Primary Beneficiary [Member] \| Fair Value, Recurring [Member] \| US States and Political Subdivisions Debt Securities
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Debt Securities, Trading	$ 0	$ 43,000

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Derivative Credit Risk Valuation Adjustment, Derivative Liabilities	$ 283	$ 19
Derivative liabilities	$ 37,000	$ 38,000
Weighted average discounted rate of estimated future premium payments to be paid by the VIEs	3.10%	3%
Derivative assets	$ 26,000	$ 27,000
Derivative assets	26,000	28,000
Warrants [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Derivative assets	1,000	1,000
Fair Value Measured at Net Asset Value Per Share [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Other investments	$ 449,000	$ 494,000
Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Percentage of investment portfolio valued using dealer quotes	2%	5%
Minimum [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Percentage of investment portfolio valued using internal valuation models	4%	4%
Maximum [Member] \| Fixed Income Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Percentage of investment portfolio valued using external pricing services	94%	91%
Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Derivative liabilities	$ 1,106,000	$ 1,048,000
Weighted average discounted rate of estimated future premium payments to be paid by the VIEs	7.50%	6.80%
Derivative assets	$ 224,000	$ 239,000
Derivative assets	$ 224,000	$ 239,000

Fair Value Measurements - Infor

Fair Value Measurements - Information about Valuation Inputs for Fixed Income Securities Classified as Level 3 (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Inputs Yield Rate	13.40%			13.40%		11.30%
Asset-backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Coupon rate	5.98%			5.98%		5.98%
Fair Value Inputs Maturity		13 years 5 months 15 days		13 years 1 month 17 days
Yield	12%			12%		12.60%
Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	$ 3,831,000	$ 3,972,000	$ 4,795,000	$ 3,831,000	$ 4,795,000	$ 3,762,000	$ 5,738,000	$ 6,199,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(81,000)		(88,000)	(155,000)	(168,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held				73,000	(664,000)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)	(124,000)		(460,000)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	64,000		(395,000)	152,000	(572,000)
Fair Value, Inputs, Level 3 [Member] \| Investments [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	81,000	$ 81,000	81,000	81,000	81,000	79,000	86,000	91,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	0		0	(1,000)	(1,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held				1,000	1,000
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI			(5,000)	3,000	(10,000)
Fair Value, Inputs, Level 3 [Member] \| Other Assets [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	0		0	0	0	0		0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements				0	0
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held				0	0
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI				0	0
Fair Value, Inputs, Level 3 [Member] \| Derivative Financial Instruments, Liabilities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	25,000		38,000	25,000	$ 38,000	26,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements				0
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held				0
Corporate Obligations [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Recurring [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Inputs Maturity		1 year 9 months			1 year 3 months
Derivative Financial Instruments, Liabilities [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability								70,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements					$ (4,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held					(29,000)
Derivative Financial Instruments, Liabilities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Derivative Financial Instruments, Liabilities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	25,000	$ 31,000	38,000	25,000	38,000		52,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	0		(2,000)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)	(5,000)		(12,000)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0		0	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Fair Value, Inputs, Level 3 [Member] \| Corporate Obligations [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability								3,320,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements					(18,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held					(458,000)
Variable Interest Entity, Primary Beneficiary [Member] \| Fair Value, Inputs, Level 3 [Member] \| Loans Receivable [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability								$ 2,718,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements					(145,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held					(178,000)
Variable Interest Entity, Primary Beneficiary [Member] \| Investment Contracts [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	1,952,000		2,533,000	1,952,000	2,533,000	1,828,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements				(12,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held				80,000
Variable Interest Entity, Primary Beneficiary [Member] \| Investment Contracts [Member] \| Fair Value, Inputs, Level 3 [Member] \| Corporate Obligations [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	1,952,000	2,003,000	2,533,000	1,952,000	2,533,000		3,131,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(12,000)		(18,000)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)	(53,000)		(365,000)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	14,000		(215,000)	57,000	(311,000)
Variable Interest Entity, Primary Beneficiary [Member] \| Loan Origination Commitments [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	1,772,000		2,144,000	1,772,000	2,144,000	$ 1,829,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements				(141,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held				(7,000)
Variable Interest Entity, Primary Beneficiary [Member] \| Loan Origination Commitments [Member] \| Fair Value, Inputs, Level 3 [Member] \| Loans Receivable [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	1,772,000	$ 1,856,000	2,144,000	1,772,000	2,144,000		$ 2,469,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(69,000)		(68,000)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)	(66,000)		(83,000)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	$ 50,000		$ (174,000)	$ 92,000	$ (251,000)

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Information about Described Model Inputs Used to Determine Fair Value of Each Class of Credit Derivatives (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair value of derivative liabilities		$ 36
Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair value of derivative liabilities		0
Real Estate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other investments		23	$ 22
Interest Rate Contract [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other investments		74	80
Illiquid Investments [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other investments		$ 85	$ 84
Asset-backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Inputs Coupon Rate		5.98%	5.98%
Fair Value Inputs Maturity	13 years 5 months 15 days	13 years 1 month 17 days
Fair Value Inputs Yield		12%	12.60%

Fair Value Measurements - Inf_2

Fair Value Measurements - Information about Valuation Inputs for Variable Interest Entity Assets and Liabilities Classified as Level 3 (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Estimated Future Premium Payments Minimum Discounted Rate	6.20%		6.20%			5.80%
Estimated Future Premium Payments Maximum Discounted Rate	9.40%		9.40%			8.50%
Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	$ 3,831,000	$ 4,795,000	$ 3,831,000	$ 4,795,000	$ 3,972,000	$ 3,762,000	$ 5,738,000	$ 6,199,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings	(124,000)	(460,000)	73,000	(664,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	64,000	(395,000)	152,000	(572,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(81,000)	(88,000)	(155,000)	(168,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held			73,000	(664,000)
Fair Value, Inputs, Level 3 [Member] \| Investments [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	81,000	81,000	81,000	81,000	81,000	79,000	86,000	91,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings	0	0	1,000	1,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	0	(5,000)	3,000	(10,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	0	0	(1,000)	(1,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held			1,000	1,000
Fair Value, Inputs, Level 3 [Member] \| Other Assets [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	0	0	0	0		0		0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings			0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss			0	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements			0	0
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held			0	0
Fair Value, Inputs, Level 3 [Member] \| Derivative Financial Instruments, Liabilities [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	25,000	38,000	25,000	38,000		26,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings			0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss			0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements			0
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held			0
Fair Value, Inputs, Level 3 [Member] \| Loans Receivable [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability								2,718,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings				(178,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss				(251,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements				(145,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held				(178,000)
Fair Value, Inputs, Level 3 [Member] \| Corporate Debt Securities [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability								3,320,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings				(458,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss				(311,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements				(18,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held				(458,000)
Loan Origination Commitments [Member] \| Fair Value, Inputs, Level 3 [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	1,772,000	2,144,000	1,772,000	2,144,000		1,829,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings			(7,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss			92,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements			(141,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held			(7,000)
Loan Origination Commitments [Member] \| Fair Value, Inputs, Level 3 [Member] \| Loans Receivable [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	1,772,000	2,144,000	1,772,000	2,144,000	1,856,000		2,469,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings	(66,000)	(83,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	50,000	(174,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(69,000)	(68,000)
Derivative Financial Instruments, Liabilities [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability								$ 70,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings				(29,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss				0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements				(4,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held				(29,000)
Derivative Financial Instruments, Liabilities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Derivative Financial Instruments, Liabilities [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	25,000	38,000	25,000	38,000	31,000		52,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings	(5,000)	(12,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	0	(2,000)
Investment Contracts [Member] \| Fair Value, Inputs, Level 3 [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	1,952,000	2,533,000	1,952,000	2,533,000		$ 1,828,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings			80,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss			57,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements			(12,000)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held			80,000
Investment Contracts [Member] \| Fair Value, Inputs, Level 3 [Member] \| Corporate Debt Securities [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability	1,952,000	2,533,000	$ 1,952,000	$ 2,533,000	$ 2,003,000		$ 3,131,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Earnings	(53,000)	(365,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Gain Loss Included In Other Comprehensive Income Loss	14,000	(215,000)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	$ (12,000)	$ (18,000)

Fair Value Measurements - Sum_3

Fair Value Measurements - Summary of Changes in Level 3 Fair Value Category (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($) level3FinancialInstruments	Jun. 30, 2022 USD ($) level3FinancialInstruments
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis Asset or Liability, Transfers into or out of Level 3 \| level3FinancialInstruments			0	0
Level 3 [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	$ (81,000)	$ (88,000)	$ (155,000)	$ (168,000)
Level 3 [Member] \| Investment Contracts [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements			(12,000)
Level 3 [Member] \| Loans [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements			(141,000)
Level 3 [Member] \| Derivative Financial Instruments, Liabilities [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements				(4,000)
Level 3 [Member] \| Loans Receivable [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements				(145,000)
Level 3 [Member] \| Loans Receivable [Member] \| Loans [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	(69,000)	(68,000)
Level 3 [Member] \| Investments [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	0	0	(1,000)	(1,000)
Level 3 [Member] \| Other Assets [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements			0	0
Level 3 [Member] \| Derivative Financial Instruments, Liabilities [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements			$ 0
Level 3 [Member] \| Derivative Financial Instruments, Liabilities [Member] \| Derivative Financial Instruments, Liabilities [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	0	(2,000)
Level 3 [Member] \| Corporate Debt Securities [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements				$ (18,000)
Level 3 [Member] \| Corporate Debt Securities [Member] \| Investment Contracts [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Or Liability Settlements	$ (12,000)	$ (18,000)

Fair Value Measurements - Sum_4

Fair Value Measurements - Summary of Gains and Losses (Realized and Unrealized) Relating to Level 3 Assets and Liabilities Included in Earnings (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2021
Net Investment Income [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total gains or losses included in earnings for the period	$ 0	$ 0	$ 1	$ 1
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held	0	0	0		$ 0
Interest Rate Swap [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held			0		(29)
Gain (Loss) on Derivative Instruments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total gains or losses included in earnings for the period	(5)	(12)	0	$ (29)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held	(5)	(12)
Income Loss On Variable Interest Entities [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total gains or losses included in earnings for the period	(119)	(448)	72		(636)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held	(119)	(448)	72		(636)
Other Income or (Loss) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total gains or losses included in earnings for the period	0	0	0		0
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held	$ 0	$ 0	$ 0		$ 0

Insurance Contracts - Additiona

Insurance Contracts - Additional Information (Details) € in Millions, £ in Millions, $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	Jun. 30, 2023 GBP (£)	Jun. 30, 2023 EUR (€)	Mar. 31, 2023 USD ($)	Jun. 30, 2022 GBP (£)	Jun. 30, 2022 EUR (€)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Insurance [Line Items]
Reinsurance Recoverable Credit Exposure	$ 87		$ 87		$ 60
Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Rmbs Subrogation	0		0		140
Financial Guarantee Insurance Contracts, Premium Receivable	$ 253	$ 288	$ 253	$ 288	$ 254							$ 320
Estimated Future Premium Payments Weighted Average Discounted Rate	3.10%		3.10%		3%	3.10%	3.10%
Reinsurance Payable	$ 96		$ 96		$ 39
Weighted average period of future premiums			7 years 10 months 24 days		8 years
Uncollectable premium receivables	5		$ 5		$ 5
Reinsurance recoveries of losses included in losses and loss expenses			(45)	(14)
Subrogation recoveries, net of reinsurance	0		0		(140)
Amortization of Intangible Assets	7	13	13	28
Intangible assets	317		317		326
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,303	846	1,303	846	$ 1,305			$ 1,307			$ 974	$ 1,098
Past Due Premiums	0	0	$ 0	$ 0
Loss Reserves [Member]
Insurance [Line Items]
Weighted average risk-free rate used to discount loss reserves			3.80%	3.90%
United Kingdom, Pounds
Insurance [Line Items]
Financial Guarantee Insurance Contracts, Premium Receivable	76	91	$ 76	$ 91		£ 60			£ 74
Euro Member Countries, Euro
Insurance [Line Items]
Financial Guarantee Insurance Contracts, Premium Receivable	$ 14	$ 15	$ 14	$ 15			€ 12			€ 14

Financial Guarantee Insurance C

Financial Guarantee Insurance Contracts - Summary of Gross Premium Receivable Roll-Forward (Direct and Assumed Contracts) (Details) $ in Thousands, € in Millions, £ in Millions	3 Months Ended						6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2023 GBP (£)	Jun. 30, 2023 EUR (€)	Jun. 30, 2022 USD ($)	Jun. 30, 2022 GBP (£)	Jun. 30, 2022 EUR (€)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Insurance [Line Items]
Allowance for Doubtful Accounts, Premiums and Other Receivables	$ 5,000			$ 6,000			$ 5,000	$ 6,000	$ 5,000	$ 5,000	$ 8,000	$ 9,000
Past Due Premiums Receivable	0						0			0
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Beginning premium receivable							254,000	320,000
Premium receipts							15,000	22,000
Adjustments for changes in expected and contractual cash flows							6,000	(5,000)
Accretion of premium receivable discount							4,000	4,000
Uncollectable premiums							1,000	3,000
Other adjustments (including foreign exchange)							4,000	(12,000)
Ending premium receivable	253,000			288,000			253,000	288,000
Premium Receivable, Allowance for Credit Loss	5,000						5,000			5,000
Premium Receivable, Credit Loss Expense (Reversal)	(1,000)			(1,000)			(1,000)	(2,000)
Premium Receivable, Allowance for Credit Loss, Writeoff	0			(1,000)			0	(1,000)
Premium Receivable, Allowance for Credit Loss, Recovery	0			0			0	0
Financing Receivable, 90 Days or More Past Due, Still Accruing	0						0			0
Premiums Receivable, Gross	257,000						257,000			259,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,303,000			846,000			1,303,000	846,000	$ 1,307,000	1,305,000	$ 974,000	$ 1,098,000
Premiums Receivable, Net	276,000						276,000			269,000
Real Estate [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Other investments	23,000						23,000			22,000
Real Estate [Member] \| Foreign Exchange
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Other adjustments (including foreign exchange)							4,000	(11,000)
Specialty Property & Casualty Program
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	23,000						23,000			16,000
Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	145,000						145,000			150,000
Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	23,000						23,000			24,000
International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	89,000						89,000			85,000
I/SL [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	222,000						222,000			217,000
I/SL [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	138,000						138,000			142,000
I/SL [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	4,000						4,000			5,000
I/SL [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	80,000						80,000			70,000
IA [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	5,000						5,000			10,000
IA [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	3,000						3,000			3,000
IA [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	1,000						1,000			1,000
IA [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	1,000						1,000			7,000
II [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	13,000						13,000			5,000
II [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	5,000						5,000			5,000
II [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
II [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	8,000						8,000			0
III [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	7,000						7,000			16,000
III [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
III [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	7,000						7,000			7,000
III [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			9,000
IV [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	10,000						10,000			11,000
IV [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
IV [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	10,000						10,000			11,000
IV [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
United Kingdom, Pounds
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Ending premium receivable	76,000	£ 60		91,000	£ 74		76,000	91,000
Euro Member Countries, Euro
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Ending premium receivable	14,000		€ 12	$ 15,000		€ 14	14,000	$ 15,000
Other Public Finance Sectors [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	2,000						2,000			2,000
Other Public Finance Sectors [Member] \| I/SL [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	2,000						2,000			2,000
Other Public Finance Sectors [Member] \| IA [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Other Public Finance Sectors [Member] \| II [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Other Public Finance Sectors [Member] \| III [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Other Public Finance Sectors [Member] \| IV [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Other International [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	3,000						3,000			2,000
Other International [Member] \| I/SL [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	3,000						3,000			2,000
Other International [Member] \| IA [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Other International [Member] \| II [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Other International [Member] \| III [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Other International [Member] \| IV [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Mortgage Backed And Home Equity [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	11,000						11,000			11,000
Mortgage Backed And Home Equity [Member] \| I/SL [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Mortgage Backed And Home Equity [Member] \| IA [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Mortgage Backed And Home Equity [Member] \| II [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Mortgage Backed And Home Equity [Member] \| III [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Mortgage Backed And Home Equity [Member] \| IV [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	10,000						10,000			11,000
Student Loans [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	8,000						8,000			8,000
Student Loans [Member] \| I/SL [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			1,000
Student Loans [Member] \| IA [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			1,000
Student Loans [Member] \| II [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Student Loans [Member] \| III [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	7,000						7,000			7,000
Student Loans [Member] \| IV [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Other Structured Finance [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	4,000						4,000			4,000
Other Structured Finance [Member] \| I/SL [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	4,000						4,000			4,000
Other Structured Finance [Member] \| IA [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Other Structured Finance [Member] \| II [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Other Structured Finance [Member] \| III [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Other Structured Finance [Member] \| IV [Member] \| Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Sovereign And Sub Sovereign [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	69,000						69,000			64,000
Sovereign And Sub Sovereign [Member] \| I/SL [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	59,000						59,000			49,000
Sovereign And Sub Sovereign [Member] \| IA [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	1,000						1,000			7,000
Sovereign And Sub Sovereign [Member] \| II [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	8,000						8,000			0
Sovereign And Sub Sovereign [Member] \| III [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			9,000
Sovereign And Sub Sovereign [Member] \| IV [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Investor Owned And Public Utilities [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	18,000						18,000			18,000
Investor Owned And Public Utilities [Member] \| I/SL [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	18,000						18,000			18,000
Investor Owned And Public Utilities [Member] \| IA [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Investor Owned And Public Utilities [Member] \| II [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Investor Owned And Public Utilities [Member] \| III [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Investor Owned And Public Utilities [Member] \| IV [Member] \| International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Housing Revenue [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	144,000						144,000			148,000
Housing Revenue [Member] \| I/SL [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	136,000						136,000			140,000
Housing Revenue [Member] \| IA [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	3,000						3,000			3,000
Housing Revenue [Member] \| II [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	5,000						5,000			5,000
Housing Revenue [Member] \| III [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0						0			0
Housing Revenue [Member] \| IV [Member] \| Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	$ 0						$ 0			$ 0

Insurance Contracts - Effect of

Insurance Contracts - Effect of Reinsurance on Premiums Written and Earned (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Written	$ 55	$ 37	$ 115	$ 67
Assumed Reinsurance Premiums Written	0	0	0	0
Ceded Reinsurance Premiums Written	100	27	142	46
Premiums written, net of reinsurance	45	(9)	27	(21)
Direct Premiums Earned	52	30	98	53
Assumed Reinsurance Premiums Earned	0	0	0	0
Ceded Reinsurance Premiums Earned	$ 37	$ 16	$ 69	$ 24

Insurance Contracts - Summarize

Insurance Contracts - Summarized Future Gross Undiscounted Premiums Expected to be Collected, and Future Expected Premiums Earned, Net of Reinsurance (Details) $ in Millions	Jun. 30, 2023 USD ($)
Future premiums expected to be collected, September 30, 2021	$ 7
Future premiums expected to be collected, December 31, 2021	5
Future premiums expected to be collected, December 31, 2022	27
Future premiums expected to be collected, December 31, 2023	26
Future premiums expected to be collected, December 31, 2024	25
Future premiums expected to be collected, December 31, 2025	24
Future premiums expected to be collected, December 31, 2030	100
Future premiums expected to be collected, December 31, 2035	63
Future premiums expected to be collected, December 31, 2040	29
Future premiums expected to be collected, December 31, 2045	14
Future premiums expected to be collected, December 31, 2050	4
Future premiums expected to be collected, December 31, 2055	0
Future premiums expected to be collected, Total	323
Future expected premiums to be earned, net of reinsurance, September 30, 2021	4
Future expected premiums to be earned, net of reinsurance, December 31, 2021	4
Future expected premiums to be earned, net of reinsurance, December 31, 2022	16
Future expected premiums to be earned, net of reinsurance, December 31, 2023	15
Future expected premiums to be earned, net of reinsurance, December 31, 2024	15
Future expected premiums to be earned, net of reinsurance, December 31, 2025	14
Future expected premiums to be earned, net of reinsurance, December 31, 2030	58
Future expected premiums to be earned, net of reinsurance, December 31, 2035	33
Future expected premiums to be earned, net of reinsurance, December 31, 2040	11
Future expected premiums to be earned, net of reinsurance, December 31, 2045	4
Future expected premiums to be earned, net of reinsurance, December 31, 2050	1
Future expected premiums to be earned, net of reinsurance, December 31, 2055	0
Future expected premiums to be earned, net of reinsurance, Total	$ 176

Insurance Contracts Financial G

Insurance Contracts Financial Guarantee Insurance Contracts - Components of Loss and Loss Expense Reserves and Subrogation Recoverable (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Components of Loss and Loss Expense Reserves and Subrogation Recoverable [Line Items]
Ceded Loss And Loss Expenses Paid Not Yet Recovered		$ 0
Policyholder Benefits and Claims Incurred, Ceded	$ 45	14
Subrogation recoverable	(139)		$ (271)
Claim liability reported on Balance Sheet, before reinsurance	594		444
Liability for Claims and Claims Adjustment Expense	863		805
Liability for Claim and Claim Adjustment Expenses Net of Subrogation recoverables	724	$ (647)	534	$ (522)
Property and Casualty, Commercial Insurance
Components of Loss and Loss Expense Reserves and Subrogation Recoverable [Line Items]
Liability for Claims and Claims Adjustment Expense	130		90
Liability for Claim and Claim Adjustment Expenses Net of Subrogation recoverables	130		90
Present Value of Expected Net Cash Flows- Claims and Loss Expenses [Member]
Components of Loss and Loss Expense Reserves and Subrogation Recoverable [Line Items]
Subrogation recoverable	2		5
Claim liability reported on Balance Sheet, before reinsurance	815		791
Liability for Claims and Claims Adjustment Expense	813		787
Present Value of Expected Net Cash Flows-Recoveries [Member]
Components of Loss and Loss Expense Reserves and Subrogation Recoverable [Line Items]
Subrogation recoverable	(140)		(276)
Claim liability reported on Balance Sheet, before reinsurance	(190)		(319)
Liability for Claims and Claims Adjustment Expense	(50)		(44)
Unearned Premium Reserve [Member]
Components of Loss and Loss Expense Reserves and Subrogation Recoverable [Line Items]
Subrogation recoverable	0		0
Claim liability reported on Balance Sheet, before reinsurance	(31)		(28)
Liability for Claims and Claims Adjustment Expense	$ (31)		$ (28)

Insurance Contracts - Summary o

Insurance Contracts - Summary of Loss Reserve Roll-Forward, Net of Subrogation Recoverable and Reinsurance (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021
Loss And Loss Adjustment Expense Reserves [Line Items]
Impact of VIE Consolidation on Gross Loss and Loss Reserves	$ 0	$ 292
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Beginning balance of net loss and loss expense reserves	419	(578)
Current Year Claims and Claims Adjustment Expense	8	3
Prior Year Claims and Claims Adjustment Expense	18	9
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims	25	12
Claim and loss expense payments, net of subrogation and reinsurance	(1)	0
Claim and loss expense (payments) recoveries, net of subrogation and reinsurance	136	158
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid	(135)	(157)
Liability for Unpaid Claims and Claims Adjustment Expense, Foreign Currency Translation Gain (Loss)	0	(2)
Liability for Unpaid Claims and Claims Adjustment Expense, Net	580	(410)	$ 419	$ (578)
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	144	55	115	56
Policyholder Benefits and Claims Incurred, Ceded	45	14
Net Incurred RMBS Subrogation Recoveries	0	(242)
Ceded Loss And Loss Expenses Paid Not Yet Recovered		0
Liability for Claim and Claim Adjustment Expenses Net of Subrogation recoverables	724	$ (647)	534	$ (522)
Financial Guarantee
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Ceded Loss And Loss Expenses Paid Not Yet Recovered	0		0
Loss Reserves Ceded To Reinsurers	$ 33		$ 33

Insurance Contracts - Summary_2

Insurance Contracts - Summary of Information Related to Policies Currently Included in Ambac's Loss Reserves or Subrogation Recoverable (Details) $ in Millions	6 Months Ended	9 Months Ended
	Jun. 30, 2023 USD ($) Policies	Sep. 30, 2022	Dec. 31, 2022 USD ($) Policies	Jun. 30, 2022 USD ($)
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Ceded Loss And Loss Expenses Paid Not Yet Recovered				$ 0
Number of policies \| Policies	163		162
Remaining weighted-average contract period (in years)	12 years	14 years
Gross insured contractual payments outstanding:
Principal	$ 4,258		$ 4,047
Interest	1,784		1,750
Total	6,042		5,797
Gross undiscounted claim liability	1,296		1,279
Discount, gross claim liability	486		496
Gross claim liability before all subrogation and before reinsurance	(810)		783
Less:
Gross RMBS subrogation			(140)
Discount, RMBS subrogation			0
Discounted RMBS subrogation, before reinsurance	0		(140)
Less:
Gross other subrogation	(257)		(233)
Discount, other subrogation	67		54
Discounted other subrogation, before reinsurance	(190)		(179)
Gross claim liability, net of all subrogation and discounts, before reinsurance	(620)		464
Less: Unearned premium reserves	(31)		(28)
Plus: Loss adjustment expenses reserves	5		8
Claim liability reported on Balance Sheet, before reinsurance	594		444
Reinsurance recoverable reported on Balance Sheet	33		33
Financial Guarantee
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Ceded Loss And Loss Expenses Paid Not Yet Recovered	5
Financial Guarantee
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Loss Reserves Ceded To Reinsurers	33		33
Ceded Loss And Loss Expenses Paid Not Yet Recovered	$ 0		$ 0
I/SL [Member]
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Number of policies \| Policies	32		37
Remaining weighted-average contract period (in years)	8 years	7 years
Gross insured contractual payments outstanding:
Principal	$ 573		$ 709
Interest	389		526
Total	962		1,235
Gross undiscounted claim liability	3		4
Discount, gross claim liability	1		1
Gross claim liability before all subrogation and before reinsurance	(3)		3
Less:
Gross RMBS subrogation			0
Discount, RMBS subrogation			0
Discounted RMBS subrogation, before reinsurance			0
Less:
Gross other subrogation	(15)		(14)
Discount, other subrogation	3		2
Discounted other subrogation, before reinsurance	(12)		(12)
Gross claim liability, net of all subrogation and discounts, before reinsurance	9		9
Less: Unearned premium reserves	(1)		(2)
Plus: Loss adjustment expenses reserves	0		1
Claim liability reported on Balance Sheet, before reinsurance	(10)		(10)
Reinsurance recoverable reported on Balance Sheet	$ 1		$ 1
IA [Member]
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Number of policies \| Policies	9		6
Remaining weighted-average contract period (in years)	13 years	19 years
Gross insured contractual payments outstanding:
Principal	$ 633		$ 200
Interest	352		198
Total	986		399
Gross undiscounted claim liability	12		4
Discount, gross claim liability	2		1
Gross claim liability before all subrogation and before reinsurance	(10)		3
Less:
Gross RMBS subrogation			0
Discount, RMBS subrogation			0
Discounted RMBS subrogation, before reinsurance			0
Less:
Gross other subrogation	(2)		(4)
Discount, other subrogation	0		0
Discounted other subrogation, before reinsurance	(2)		(3)
Gross claim liability, net of all subrogation and discounts, before reinsurance	(7)		0
Less: Unearned premium reserves	(6)		(2)
Plus: Loss adjustment expenses reserves	1		1
Claim liability reported on Balance Sheet, before reinsurance	2		(2)
Reinsurance recoverable reported on Balance Sheet	$ 0		$ 0
II [Member]
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Number of policies \| Policies	12		9
Remaining weighted-average contract period (in years)	12 years	14 years
Gross insured contractual payments outstanding:
Principal	$ 1,048		$ 459
Interest	286		286
Total	1,334		745
Gross undiscounted claim liability	56		43
Discount, gross claim liability	9		7
Gross claim liability before all subrogation and before reinsurance	(47)		36
Less:
Gross RMBS subrogation			0
Discount, RMBS subrogation			0
Discounted RMBS subrogation, before reinsurance			0
Less:
Gross other subrogation	0		0
Discount, other subrogation	0		0
Discounted other subrogation, before reinsurance	0		0
Gross claim liability, net of all subrogation and discounts, before reinsurance	(47)		36
Less: Unearned premium reserves	(12)		(5)
Plus: Loss adjustment expenses reserves	1		0
Claim liability reported on Balance Sheet, before reinsurance	37		32
Reinsurance recoverable reported on Balance Sheet	$ 8		$ 8
III [Member]
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Number of policies \| Policies	12		12
Remaining weighted-average contract period (in years)	14 years	14 years
Gross insured contractual payments outstanding:
Principal	$ 408		$ 1,000
Interest	146		156
Total	553		1,156
Gross undiscounted claim liability	409		446
Discount, gross claim liability	145		162
Gross claim liability before all subrogation and before reinsurance	(263)		284
Less:
Gross RMBS subrogation			0
Discount, RMBS subrogation			0
Discounted RMBS subrogation, before reinsurance			0
Less:
Gross other subrogation	(29)		(31)
Discount, other subrogation	5		5
Discounted other subrogation, before reinsurance	(24)		(26)
Gross claim liability, net of all subrogation and discounts, before reinsurance	(239)		258
Less: Unearned premium reserves	0		(8)
Plus: Loss adjustment expenses reserves	1		2
Claim liability reported on Balance Sheet, before reinsurance	239		252
Reinsurance recoverable reported on Balance Sheet	$ 20		$ 21
IV [Member]
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Number of policies \| Policies	93		93
Remaining weighted-average contract period (in years)	12 years	12 years
Gross insured contractual payments outstanding:
Principal	$ 1,568		$ 1,646
Interest	593		565
Total	2,161		2,210
Gross undiscounted claim liability	769		729
Discount, gross claim liability	320		316
Gross claim liability before all subrogation and before reinsurance	(449)		413
Less:
Gross RMBS subrogation			(140)
Discount, RMBS subrogation			0
Discounted RMBS subrogation, before reinsurance			(140)
Less:
Gross other subrogation	(200)		(172)
Discount, other subrogation	56		42
Discounted other subrogation, before reinsurance	(144)		(130)
Gross claim liability, net of all subrogation and discounts, before reinsurance	(305)		143
Less: Unearned premium reserves	(10)		(10)
Plus: Loss adjustment expenses reserves	1		4
Claim liability reported on Balance Sheet, before reinsurance	297		137
Reinsurance recoverable reported on Balance Sheet	$ 4		$ 3
V [Member]
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Number of policies \| Policies	5		5
Remaining weighted-average contract period (in years)	7 years	7 years
Gross insured contractual payments outstanding:
Principal	$ 28		$ 34
Interest	19		19
Total	46		53
Gross undiscounted claim liability	46		53
Discount, gross claim liability	9		9
Gross claim liability before all subrogation and before reinsurance	(37)		43
Less:
Gross RMBS subrogation			0
Discount, RMBS subrogation			0
Discounted RMBS subrogation, before reinsurance			0
Less:
Gross other subrogation	(12)		(12)
Discount, other subrogation	4		4
Discounted other subrogation, before reinsurance	(8)		(8)
Gross claim liability, net of all subrogation and discounts, before reinsurance	(29)		35
Less: Unearned premium reserves	(1)		(1)
Plus: Loss adjustment expenses reserves	0		0
Claim liability reported on Balance Sheet, before reinsurance	28		34
Reinsurance recoverable reported on Balance Sheet	$ 0		$ 0

Insurance Contracts - Summary_3

Insurance Contracts - Summary of Information Related to Policies Currently Included in Ambac's Loss Reserves or Subrogation Recoverable (Phantom) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Loss and loss expense reserves	$ 863	$ 805
Subrogation recoverable	(139)	(271)
Liability for Claims	$ 863	$ 805
Ceded Loss And Loss Expenses Paid Not Yet Recovered			$ 0

Insurance Contracts - Summary_4

Insurance Contracts - Summary of Balance of RMBS Subrogation Recoveries and Related Claim Liabilities, by Estimation Approach (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Schedule Of Balance Of Rmbs Subrogation Recoveries And Related Claim Liabilities By Estimation Approach [Line Items]
Balance Of Rmbs Subrogation Recoveries Net Of Reinsurance	$ 0	$ (140)
Subrogation recoveries	$ 0	$ 140

Insurance Contracts Financial_2

Insurance Contracts Financial Guarantee Insurance Contracts - Summary of Percentage Ceded to Reinsurers and Reinsurance Recoverable and Rating Levels (Details) $ in Millions	Jun. 30, 2022 USD ($)
Insurance [Abstract]
Ceded Loss And Loss Expenses Paid Not Yet Recovered	$ 0

Insurance - Summary of Percenta

Insurance - Summary of Percentage Ceded to Reinsurers and Reinsurance Recoverable and Rating Levels (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Ceded Loss And Loss Expenses Paid Not Yet Recovered			$ 0
Reinsurance Recoverable, Allowance for Credit Loss	$ 68
Reinsurance Recoverables, Gross	149,000
Unsecured Reinsurance Recoverables	87,000
Reinsurance Recoverable, Gross, All Other	29,000
Unsecured Reinsurance Recoverable, All Other	10,000
Letters of Credit Outstanding, Amount	$ 113,000
Number of Reinsurers Covering Majority	3
Percentage of Ceded Reinsurance Recoverable Represented by Top Three	80.80%
Uncollateralized Credit Exposure Supoorted by Unlimited Uncapped Indemnity	$ 43,000	$ 45,000
Deferred Ceded Premiums And Reinsurance Recoverables	$ 346,000
Reinsurance, Reinsured Risk, Percentage	70%
Financial Guarantee
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Ceded Loss And Loss Expenses Paid Not Yet Recovered	$ 0	$ 0
QBE Insurance Corporation \| Property and Casualty, Commercial Insurance
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Reinsurance Recoverables, Gross	40,000
Unsecured Reinsurance Recoverables	40,000
Assured Guaranty Re Ltd \| Property and Casualty, Commercial Insurance
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Reinsurance Recoverables, Gross	29,000
Unsecured Reinsurance Recoverables	0
General Reinsurance Company \| Property and Casualty, Commercial Insurance
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Reinsurance Recoverables, Gross	51,000
Unsecured Reinsurance Recoverables	$ 37,000

Insurance Contracts - Premium E

Insurance Contracts - Premium Earned (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Insurance [Line Items]
Premiums Earned, Net	$ 15	$ 14	$ 29	$ 28
Direct Premiums Written	55	37	115	67
Direct Premiums Earned	52	30	98	53
Assumed Reinsurance Premiums Written	0	0	0	0
Assumed Reinsurance Premiums Earned	0	0	0	0
Ceded Premiums Written	100	27	142	46
Ceded Reinsurance Premiums Earned	37	16	69	24
Premiums Written, Net	(45)	9	(27)	21
Premiums Receivable, Net	$ 276		$ 276		$ 269
Estimated Future Premium Payments Weighted Average Discounted Rate	3.10%		3.10%		3%
Weighted average period of future premiums			7 years 10 months 24 days		8 years
Reportable Geographical Components [Member] \| United States [Member]
Insurance [Line Items]
Premiums Earned, Net	$ 12	10	$ 23	20
Reportable Geographical Components [Member] \| United Kingdom [Member]
Insurance [Line Items]
Premiums Earned, Net	3	3	5	7
Reportable Geographical Components [Member] \| Other International [Member]
Insurance [Line Items]
Premiums Earned, Net	$ 1	$ 1	$ 1	$ 2

Derivative Instruments - Summar

Derivative Instruments - Summary of Gross Fair Values of Individual Derivative Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Derivative, Collateral, Right to Reclaim Cash	$ 17	$ 6
Net Amounts of Assets Presented in the Consolidated Balance Sheet, Derivative Assets	26	27
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet, Derivative Liabilities	37	38
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	36
Gross Amount of Collateral Received/Pledged Not Offset in the Consolidated Balance Sheet, Derivative Liabilities		38
Net Amount, Derivative Assets	26	27
Derivative Asset, Fair Value, Gross Asset	26	28
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Derivative liabilities	37	38
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Derivative Liabilities Net Amount	0	0
Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Net Amounts of Assets Presented in the Consolidated Balance Sheet, Derivative Assets	25	27
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet, Derivative Liabilities	37	38
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	36	38
Net Amount, Derivative Assets	25	27
Derivative Asset, Fair Value, Gross Asset	25	27
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Derivative liabilities	37	38
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Derivative Liabilities Net Amount	0	0
Warrants [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	1	1
Derivative Asset, Fair Value, Gross Asset	1	1
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Variable Interest Entity, Primary Beneficiary [Member]
Derivatives, Fair Value [Line Items]
Net Amounts of Assets Presented in the Consolidated Balance Sheet, Derivative Assets	224	239
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	223	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet, Derivative Liabilities	1,106	1,048
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	0
Gross Amount of Collateral Received/Pledged Not Offset in the Consolidated Balance Sheet, Derivative Liabilities		0
Net Amount, Derivative Assets	1	239
Derivative Asset, Fair Value, Gross Asset	224	239
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Derivative liabilities	1,106	1,048
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Derivative Liabilities Net Amount	1,106	1,048
Variable Interest Entity, Primary Beneficiary [Member] \| Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Net Amounts of Assets Presented in the Consolidated Balance Sheet, Derivative Assets	185	190
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	184
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet, Derivative Liabilities	1,106	1,048
Net Amount, Derivative Assets	1	190
Derivative Asset, Fair Value, Gross Asset	185	190
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Derivative liabilities	1,106	1,048
Derivative Liabilities Net Amount	1,106	1,048
Variable Interest Entity, Primary Beneficiary [Member] \| Currency Swaps [Member]
Derivatives, Fair Value [Line Items]
Net Amounts of Assets Presented in the Consolidated Balance Sheet, Derivative Assets	39	49
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	39	0
Net Amount, Derivative Assets	0	49
Derivative Asset, Fair Value, Gross Asset	39	$ 49
Derivative Asset, Fair Value, Amount Offset Against Collateral	$ 0

Derivative Instruments - Additi

Derivative Instruments - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Value of right to reclaim cash collateral and posted margin, recorded in Other assets	$ 17		$ 17		$ 6
Gains in change in fair value of the call options	0	$ 29	(3)	$ 86
Net liability fair value of all derivative instruments linked to Ambac's own credit risk	36		36		38
Fair value of posted assets as collateral	54		54		54
Derivative assets	26		26		28
Variable Interest Entity, Primary Beneficiary [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Value of obligation to return cash collateral, recorded in "Other liabilities"	263		263		0
Derivative assets	224		224		239
Warrants [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative assets	$ 1		$ 1		$ 1

Derivative Instruments - Summ_2

Derivative Instruments - Summary of Location and Amount of Gains and Losses of Derivative Contracts (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 0	$ 29	$ (3)	$ 86
Derivative, Gain (Loss) on Derivatives, Total Net	97	307	(8)	376
Net gains (losses) on derivative contracts [Domain] \| Interest Rate Swap [Member]
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1	17	(3)	47
Net gains (losses) on derivative contracts [Domain] \| Futures Contracts [Member]
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	11	0	37
Net gains (losses) on derivative contracts [Domain] \| Warrants [Member]
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	1	0	1
Income Loss On Variable Interest Entities [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	96	278	(5)	289
Income Loss On Variable Interest Entities [Member] \| Interest Rate Swap [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	97	264	(2)	269
Income Loss On Variable Interest Entities [Member] \| Currency Swaps [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (1)	$ 14	$ (3)	$ 20

Derivative Instruments - Summ_3

Derivative Instruments - Summary of Notional Amounts of AFS's Trading Derivative Products (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
AFS [Member] \| Interest Rate Swap [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	$ 170	$ 337
AFS [Member] \| Interest Rate Swaps-Pay-Fixed/Receive-Variable [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	142	989
Variable Interest Entity, Primary Beneficiary [Member] \| Interest Rate Swap [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	1,655	1,573
Variable Interest Entity, Primary Beneficiary [Member] \| Interest Rate Swaps-Pay-Fixed/Receive-Variable [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	$ 898	$ 887

Derivative Instruments - Summ_4

Derivative Instruments - Summary of Notional for VIE Derivatives Outstanding (Details) - Variable Interest Entity, Primary Beneficiary [Member] - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Interest Rate Swap [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	$ 1,655	$ 1,573
Interest Rate Swaps-Pay-Fixed/Receive-Variable [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	898	887
Currency Swaps [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative products, Notional Amount	$ 163	$ 176

Intangible Assets (Details)

Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
Intangible Assets (Details) - USD ($) $ in Millions	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Intangible assets	$ 317		$ 317		$ 326
Amortization of Intangible Assets	7	$ 13	13	$ 28
Finite-Lived Intangible Assets, Net	303		303		312
PWIC
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	14		14		14
Insurance Intangible Asset [Member]
Intangible Assets, Gross (Excluding Goodwill)	1,257		1,257		1,247
Finite-Lived Intangible Assets, Accumulated Amortization	999		999		981
Intangible assets	258		258		266
Other Intangible Assets
Intangible Assets, Gross (Excluding Goodwill)	52		52		52
Finite-Lived Intangible Assets, Accumulated Amortization	7		7		6
Intangible assets	$ 45		$ 45		$ 47

Special Purpose Entities, Inc_2

Special Purpose Entities, Including Variable Interest Entities - Additional Information (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($) Entity consolidationVIE	Jun. 30, 2022 USD ($) consolidationVIE	Jun. 30, 2023 USD ($) Entity consolidationVIE	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) Entity
Variable Interest Entities [Line Items]
Variable Interest Entity Change in Fair Value of Assets and Liabilities	$ 0	$ 1,000,000	$ 2,000,000	$ 1,000,000
Realized Investment Gains (Losses)	(3,000,000)	7,000,000	(8,000,000)	17,000,000
Other Operating Income (Expense), Net	2,000,000	0	5,000,000	3,000,000
Fair value of special purpose entities	0		0
Variable Interest Entity, Measure of Activity, Income or Loss before Tax	0	$ (6,000,000)	(1,000,000)	$ 15,000,000
Long-term debt	$ 501,000,000		$ 501,000,000		$ 639,000,000
Number of Variable Interest Entities Consolidated During the Period	0	0	0	2
Number of Variable Interest Entities Deconsolidated During Period \| consolidationVIE	0	0	1
Gain (loss) from consolidating VIEs	$ 0	$ 0	$ 0	$ 28,000,000
Number of Trusts Established Resulting From Puerto Rico Restructuring Transaction			2
Variable Interest Entity Deconsolidation Gain Loss	$ 0
Consolidated Entities [Member]
Variable Interest Entities [Line Items]
Number Of Consolidated Variable Interest Entities \| Entity	8		8		9
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, before Tax	$ 1,000,000	(1,000,000)	$ 1,000,000	(2,000,000)
VIE Change in FV of Assets Liabilities, Net of Credit Risk Change	0	0	3,000,000	(1,000,000)
Gross Investment Income, Operating	3,000,000	(1,000,000)
Interest Expense, Long-term Debt	(3,000,000)	(5,000,000)	(8,000,000)	(7,000,000)
Long-term debt	$ 2,956,000,000		$ 2,956,000,000		$ 3,107,000,000
Ambac UK [Member] \| Consolidated Entities [Member]
Variable Interest Entities [Line Items]
Number Of Consolidated Variable Interest Entities \| Entity	4		4		5
Ambac UK [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Long-term debt	$ 2,785,000,000		$ 2,785,000,000		$ 2,788,000,000
Ambac Assurance [Member] \| Consolidated Entities [Member]
Variable Interest Entities [Line Items]
Number Of Consolidated Variable Interest Entities \| Entity	4		4		4
Ambac Assurance [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Long-term debt	$ 171,000,000		$ 171,000,000		$ 319,000,000
Fixed Income Investments [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Gross Investment Income, Operating			5,000,000	(5,000,000)
Realized Investment Gains (Losses)	$ 0	$ 0	$ 0	$ 1,000,000

Special Purpose Entities, Inc_3

Special Purpose Entities, Including Variable Interest Entities - Summary of Fair Value of Fixed Income Securities, by Asset-Type, Held by Consolidated Variable Interest Entities (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Variable Interest Entities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 2,033	$ 2,041
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	30	31
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	109	106
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Loans Unpaid Principal Balance	1,988	1,977
Long Term Debt Unpaid Principal Balance	3,133	3,064
Variable Interest Entity, Primary Beneficiary [Member] \| Municipal Bonds [Member]
Variable Interest Entities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 99	$ 99

Special Purpose Entities, Inc_4

Special Purpose Entities, Including Variable Interest Entities - Supplemental Information about Loans Held as Assets and Long-Term Debt Associated with Consolidated Variable Interest Entities (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Variable Interest Entities [Line Items]
Long-term debt	$ 501	$ 639
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Long-term debt	2,956	3,107
Long-term debt, Estimated fair value	2,785	2,788
Loans Unpaid Principal Balance	1,988	1,977
Long Term Debt Unpaid Principal Balance	$ 3,133	$ 3,064

Special Purpose Entities, Inc_5

Special Purpose Entities, Including Variable Interest Entities - Summary of Carrying Amount of Assets, Liabilities and Maximum Exposure to Loss of Ambac's Variable Interests in Non-Consolidated Variable Interest Entities (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Variable Interest Entities [Line Items]
Maximum Exposure To Loss	$ 21,484	$ 21,639
Insurance Assets	361	490
Insurance Liabilities	877	840
Derivative Liabilities	0
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Derivative Liabilities		1
Global Public Finance [Member]
Variable Interest Entities [Line Items]
Maximum Exposure To Loss	17,981	17,997
Insurance Assets	218	216
Insurance Liabilities	215	212
Derivative Liabilities	0	0
Global Structured Finance [Member]
Variable Interest Entities [Line Items]
Maximum Exposure To Loss	3,503	3,642
Insurance Assets	142	274
Insurance Liabilities	662	628
Derivative Liabilities	0	1
Global Structured Finance [Member] \| Residential Mortgage-Backed Securities [Member]
Variable Interest Entities [Line Items]
Maximum Exposure To Loss	2,475	2,559
Insurance Assets	135	266
Insurance Liabilities	434	400
Derivative Liabilities	0	0
Global Structured Finance [Member] \| Other Consumer Asset-Backed [Member]
Variable Interest Entities [Line Items]
Maximum Exposure To Loss	595	652
Insurance Assets	5	6
Insurance Liabilities	226	225
Derivative Liabilities	0	0
Global Structured Finance [Member] \| Other [Member]
Variable Interest Entities [Line Items]
Maximum Exposure To Loss	432	430
Insurance Assets	2	2
Insurance Liabilities	2	2
Derivative Liabilities	$ 0	$ 1

Variable Interest Entities Spec

Variable Interest Entities Special Purpose Entities, including Variable Interest Entities - Summary of Assets and Liabilities (Details) $ in Millions	Jun. 30, 2023 USD ($) Entity	Dec. 31, 2022 USD ($) Entity	Jun. 30, 2022 USD ($)
Debt Securities, Available-for-sale, Amortized Cost	$ 2,033	$ 2,041
Fixed maturity securities, at fair value	1,953
Restricted Cash	10	14	$ 5
Derivative assets	26	27
Other assets	89	84
Total assets	8,132	7,973	10,061
Interest Payable	450	427
Long-term debt	501	639
Derivative Liability	37	38
Other Liabilities	136	163
Liabilities	6,809	6,647
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	30	31
Variable Interest Entity, Primary Beneficiary [Member]
Fixed maturity securities, at fair value	2,056	1,967
Restricted Cash	266	17	$ 2
Financing Receivable, after Allowance for Credit Loss	1,772	1,829
Derivative assets	224	239
Other assets	2	2
Total assets	4,320	4,054
Long-term debt	2,785	2,788
Long-term Debt, at par less amortized discount	171	319
Long-term debt	2,956	3,107
Derivative Liability	1,106	1,048
Other Liabilities	1	5
Liabilities	4,326	4,160
Estimated Future Premium Payments Maximum Discounted Rate	263	0
Variable Interest Entity, Primary Beneficiary [Member] \| Corporate Debt Securities [Member]
Fixed maturity securities, at fair value	1,952	1,828
Variable Interest Entity, Primary Beneficiary [Member] \| Municipal Bonds [Member]
Debt Securities, Available-for-sale, Amortized Cost	99	99
Fixed maturity securities, at fair value	104	96
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	(4)
Available-for-Sale Securities, Accumulated Gross Unrealized Gain, before Tax	5	1
Variable Interest Entity, Primary Beneficiary [Member] \| US States and Political Subdivisions Debt Securities
Fixed maturity securities, at fair value	0	43
Variable Interest Entity, Primary Beneficiary [Member] \| Ambac UK [Member]
Fixed maturity securities, at fair value	1,952	1,828
Restricted Cash	264	1
Financing Receivable, after Allowance for Credit Loss	1,772	1,829
Derivative assets	224	239
Other assets	0	0
Total assets	4,213	3,896
Long-term debt	2,785	2,788
Long-term Debt, at par less amortized discount	0	0
Long-term debt	2,785	2,788
Derivative Liability	1,106	1,048
Cash collateral payable	263
Other Liabilities	0	0
Liabilities	4,154	3,836
Estimated Future Premium Payments Maximum Discounted Rate		0
Variable Interest Entity, Primary Beneficiary [Member] \| Ambac UK [Member] \| Corporate Debt Securities [Member]
Fixed maturity securities, at fair value	1,952	1,828
Variable Interest Entity, Primary Beneficiary [Member] \| Ambac UK [Member] \| Municipal Bonds [Member]
Fixed maturity securities, at fair value	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Ambac UK [Member] \| US States and Political Subdivisions Debt Securities
Fixed maturity securities, at fair value	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Ambac Assurance [Member]
Fixed maturity securities, at fair value	104	139
Restricted Cash	1	16
Financing Receivable, after Allowance for Credit Loss	0	0
Derivative assets	0	0
Other assets	2	2
Total assets	107	157
Long-term debt	0	0
Long-term Debt, at par less amortized discount	171	319
Long-term debt	171	319
Derivative Liability	0	0
Other Liabilities	1	5
Liabilities	172	324
Estimated Future Premium Payments Maximum Discounted Rate	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Ambac Assurance [Member] \| Corporate Debt Securities [Member]
Fixed maturity securities, at fair value	0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Ambac Assurance [Member] \| Municipal Bonds [Member]
Fixed maturity securities, at fair value	104	96
Variable Interest Entity, Primary Beneficiary [Member] \| Ambac Assurance [Member] \| US States and Political Subdivisions Debt Securities
Fixed maturity securities, at fair value	$ 0	$ 43
Consolidated Entities [Member]
Number Of Consolidated Variable Interest Entities \| Entity	8	9
Consolidated Entities [Member] \| Ambac UK [Member]
Number Of Consolidated Variable Interest Entities \| Entity	4	5
Consolidated Entities [Member] \| Ambac Assurance [Member]
Number Of Consolidated Variable Interest Entities \| Entity	4	4

Revenue Recognition and Defer_3

Revenue Recognition and Deferred Revenue (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2022 USD ($)
Contract with Customer, Liability, Revenue Recognized		$ 1	$ 0
Revenue from Contract with Customer, Excluding Assessed Tax	$ 10	6	25		$ 15
Contract with Customer, Receivable, after Allowance for Credit Loss	6		6			$ 7
Contract with Customer, Asset, after Allowance for Credit Loss	9		9			5
Contract with Customer, Liability	1		1			$ 1
Contract with Customer, Performance Obligation Satisfied in Previous Period	5	5
Employer Stop Loss
Revenue from Contract with Customer, Excluding Assessed Tax	2	1	7		5
Affinity Products
Revenue from Contract with Customer, Excluding Assessed Tax	5	5	10		$ 9
Commercial Auto
Revenue from Contract with Customer, Excluding Assessed Tax	2	0	5	$ 0
Product and Service, Other
Revenue from Contract with Customer, Excluding Assessed Tax	$ 1	$ 0	$ 2	$ 0
Minimum [Member]
Employee Stop Loss Time When Base Commissions Recognized Begin and End In Months	17
Maximum [Member]
Employee Stop Loss Time When Base Commissions Recognized Begin and End In Months	21

Comprehensive Income - Schedule

Comprehensive Income - Schedule of Changes in Balances of Each Component of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ (217)	$ (70)	$ (253)	$ 58
Other comprehensive income before reclassifications	(6)	122	(39)	249
Amounts reclassified from accumulated other comprehensive income	2	(4)	5	(5)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	8	(126)	44	(254)
Ending Balance	(209)	(196)	(209)	(196)
Income Tax Expense (Benefit)	2	1	6	1
Realized Investment Gains (Losses)	(3)	7	(8)	17
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(54)	49	(71)	154
Other comprehensive income before reclassifications	15	67	1	171
Amounts reclassified from accumulated other comprehensive income	3	(5)	6	(6)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(13)	(72)	5	(177)
Ending Balance	(67)	(23)	(67)	(23)
Realized Investment Gains (Losses)	3	(7)
Accumulated Translation Adjustment [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(168)	(123)	(184)	(100)
Other comprehensive income before reclassifications	(21)	55	(37)	78
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	21	(55)	37	(78)
Ending Balance	(147)	(177)	(147)	(177)
Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(1)	(1)	(1)	(1)
Other comprehensive income before reclassifications	0	0	0	0
Amounts reclassified from accumulated other comprehensive income	0	1	0	1
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0	1	0	1
Ending Balance	(1)	0	(1)	0
Other Postretirement Benefits Plan [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	6	4	3	4
Other comprehensive income before reclassifications	0	0	(3)	0
Amounts reclassified from accumulated other comprehensive income	0	0	(1)	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0	0	2	0
Ending Balance	6	4	6	4
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Income Tax Expense (Benefit)	(1)	2	(2)	2
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Income Tax Expense (Benefit)			0
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Other Postretirement Benefits Plan [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	0	0	0	0
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Amounts reclassified from accumulated other comprehensive income	0	0	(1)	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	0	0	0	0
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	0	0	(1)	0
Income Tax Expense (Benefit)	$ 0	$ 0	$ 0	$ 0

Comprehensive Income - Schedu_2

Comprehensive Income - Schedule of Amounts Reclassed Out of Each Component of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)	$ (2)	$ (1)	$ (6)	$ (1)
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Arising During Period, after Tax	0	1	0	1
Net of tax and noncontrolling interest	(13)	5	(47)	7
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	2	(4)	5	(5)
Realized Investment Gains (Losses)	(3)	7	(8)	17
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax and noncontrolling interest	3	(5)	6	(6)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	3	(5)	6	(6)
Realized Investment Gains (Losses)	3	(7)
Net realized investment gains			8	(8)
Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Arising During Period, after Tax	0	(1)	0	(1)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	1	0	1
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, before Tax, after Reclassification Adjustment	(1)	1	0	1
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net of tax and noncontrolling interest	2	(4)	5	(5)
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)	1	(2)	2	(2)
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)			0
Reclassification out of Accumulated Other Comprehensive Income [Member] \| Accumulated Gain (Loss), Financial Liability, Fair Value Option, Including Portion Attributable to Noncontrolling Interest [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)	0	0		0
Other Postretirement Benefits Plan [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0	(1)	0
Other Postretirement Benefits Plan [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)	0	0	0	0
Prior service cost	0	0	0	0
Actuarial gains (losses)	0	0	0	0
Total before tax	0	0	(1)	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 0	$ 0	$ (1)	$ 0

Net Income Per Share - Addition

Net Income Per Share - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Apr. 30, 2013
Schedule Of Earnings Per Share [Line Items]
Common stock, shares outstanding	45,303,998		45,303,998
Par value of common stock issued	$ 0.01		$ 0.01		$ 0.01
Earnings Per Share, Basic	(0.29)	$ 0.11	(1.02)	$ 0.15
Earnings Per Share, Diluted	$ (0.29)	$ 0.11	$ (1.02)	$ 0.15
Noncontrolling Interest, Change in Redemption Value	$ 0	$ 0	$ 0	$ 0
Net Income (Loss) Available to Common Stockholders, Basic	$ (13)	$ 5	$ (47)	$ 7
Common Stock [Member]
Schedule Of Earnings Per Share [Line Items]
Number of new common stock issued			330,241

Net Income Per Share - Reconcil

Net Income Per Share - Reconciliation of Common Shares Used for Basic and Diluted Earnings Per Share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of common shares used for basic earnings per share	45,757,234	45,519,093	45,661,288	46,121,927
Effect of potential dilutive shares:
Weighted average number of common shares and potential dilutive shares used for diluted earnings per share	45,757,234	45,685,349	45,661,288	46,310,687
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	4,877,617	0	4,877,617
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	556,602	471,697	555,981	388,326
Performance Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	667,365	472,592	667,365	429,243
Warrants [Member]
Effect of potential dilutive shares:
Effect of potential dilutive shares	0	0	0	0
Restricted Stock Units (RSUs) [Member]
Effect of potential dilutive shares:
Effect of potential dilutive shares	0	82,128	0	81,411
Performance Shares [Member]
Effect of potential dilutive shares:
Effect of potential dilutive shares	0	84,128	0	107,349

Net Income Per Share Schedule o

Net Income Per Share Schedule of Basic and Dilutive Securities for EPS (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Weighted Average Number of Shares Outstanding, Basic	45,757,234	45,519,093	45,661,288	46,121,927
Weighted Average Number of Shares Outstanding, Diluted	45,757,234	45,685,349	45,661,288	46,310,687
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	556,602	471,697	555,981	388,326
Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	4,877,617	0	4,877,617
Performance Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	667,365	472,592	667,365	429,243
Performance Shares [Member]
Weighted Average Number Diluted Shares Outstanding Adjustment	0	84,128	0	107,349
Restricted Stock Units (RSUs) [Member]
Weighted Average Number Diluted Shares Outstanding Adjustment	0	82,128	0	81,411

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details)	3 Months Ended
Income Taxes - Additional Information (Details)	Jun. 30, 2023
Minimum [Member]
Tax Credit Carryforward [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2030
Maximum [Member]
Tax Credit Carryforward [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2044

Income Taxes Income Taxes - Pro

Income Taxes Income Taxes - Provision for Income Taxes Charged To Income From Continuing Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Provision for Income Taxes [Line Items]
Current Federal Tax Expense (Benefit)	$ 1	$ 0	$ 1	$ 0
Income (Loss) from Continuing Operations before Income Taxes, Domestic	(18)	10	(66)	10
Current Income Tax Expense (Benefit)	2	1	4	2
Deferred Foreign Income Tax Expense (Benefit)	0	0	2	(1)
Deferred Income Tax Expense (Benefit)	0	0	2	(1)
Income Tax Expense (Benefit)	2	1	6	1
Income (Loss) from Continuing Operations before Income Taxes, Foreign	7	(4)	26	0
Current State and Local Tax Expense (Benefit)	0	0	0	0
Current Foreign Tax Expense (Benefit)	$ 0	$ 1	$ 2	$ 2

Income Taxes Income Taxes - NOL

Income Taxes Income Taxes - NOL Usage Table (Details) $ in Millions	3 Months Ended
	Jun. 30, 2023 USD ($)
Net Income Loss Reconciliation [Line Items]
NOL allocated amount	$ 3,466
Domestic Tax Authority [Member] \| Interest Expense
Net Income Loss Reconciliation [Line Items]
NOL allocated amount	$ 309
Minimum [Member]
Net Income Loss Reconciliation [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2030
Maximum [Member]
Net Income Loss Reconciliation [Line Items]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2044

Income Taxes Schedule of Income

Income Taxes Schedule of Income Before Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Schedule of Income Before Income Tax, Domestic and Foreign [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Domestic	$ (18)	$ 10	$ (66)	$ 10
Income (Loss) from Continuing Operations before Income Taxes, Foreign	7	(4)	26	0
Pretax income (loss)			(40)	9
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	$ (11)	$ 6	$ (40)	$ 9

Uncategorized Items - ambc-2023

Label	Element	Value
Goodwill, Acquired During Period	us-gaap_GoodwillAcquiredDuringPeriod	$ 15,000,000