Ambac Financial (AMBC) 10-K1 Mar 232022 FY Annual reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2022	Feb. 24, 2023	Jun. 30, 2022	Apr. 30, 2013
Entity Information [Line Items]
Entity File Number	1-10777
Document Quarterly Report	true
Document Transition Report	false
City Area Code	(212)
Entity Incorporation, State or Country Code	DE
Document Type	10-K
Amendment Flag	false
Entity Well-known Seasoned Issuer	Yes
Entity Interactive Data Current	Yes
Entity Voluntary Filers	No
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Entity Registrant Name	AMBAC FINANCIAL GROUP, INC.
Entity Central Index Key	0000874501
Current Fiscal Year End Date	--12-31
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		45,287,112
Entity Public Float			$ 510,068,047
Common Stock, Par or Stated Value Per Share				$ 0.01
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
Local Phone Number	658-7470
ICFR Auditor Attestation Flag	true
Document Period End Date	Dec. 31, 2022
Documents Incorporated by Reference	Portions of the Registrant’s Proxy Statement related to its annual meeting of stockholders are incorporated by reference in this Form 10-K in response to Part III Items 10, 11, 12, 13, and 14.
Entity Current Reporting Status	Yes
Common Stock [Member]
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	AMBC
Security Exchange Name	NYSE
Warrant [Member]
Entity Information [Line Items]
Title of 12(b) Security	Warrants
Trading Symbol	AMBC WS
Security Exchange Name	NYSE

Audit Information

Audit Information	12 Months Ended
Audit Information	Dec. 31, 2022
Document And Entity Information [Abstract]
Auditor Name	KPMG LLP
Auditor Location	New York, NY
Auditor Firm ID	185

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Assets:
Available-for-sale Securities	$ 1,966
Debt Securities, Trading and Available-for-Sale	59
Short-term Investments	507	$ 414
Other Investments	568	690
Investments, Total	2,593	2,955
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	61	23
Restricted Cash	14	5
Premiums Receivable, Net	269	323
Reinsurance Recoverables, Including Reinsurance Premium Paid	115	55
Deferred ceded premium	124	90
Subrogation recoverable	271	2,092
Derivative assets	27	76
Intangible assets	326	362
Goodwill	61	46
Other assets	84	68
Total assets	7,973	12,303
Liabilities:
Unearned premiums	372	395
Liability for Claims and Claims Adjustment Expense	805	1,570
Ceded premiums payable	39	33
Capitalized Contract Cost, Net	5	0
Long-term debt	639	2,230
Accrued interest payable	427	576
Derivative liabilities	38	95
Other liabilities	163	133
Total liabilities	$ 6,647	$ 11,187
Preferred Stock, Shares Outstanding	0	0
Preferred stock, shares authorized	20,000,000	20,000,000
Stockholders’ equity:
Preferred Stock, Value, Issued	$ 0	$ 0
Common Stock, Value, Issued	0	0
Additional paid-in capital	274	257
Accumulated other comprehensive income (loss)	(253)	58
Retained earnings	1,245	726
Treasury Stock, Value	(15)	(3)
Total Ambac Financial Group, Inc. stockholders’ equity	1,252	1,038
Nonredeemable noncontrolling interest	53	60
Total stockholders’ equity	$ 1,305	$ 1,098
Preferred stock, par value	$ 0.01
Common stock, shares issued	46,658,990	46,477,068
Common stock, shares authorized	130,000,000	130,000,000
Redeemable Noncontrolling Interest, Equity, Carrying Amount	$ 20	$ 18
Total liabilities, redeemable noncontrolling interest and stockholders’ equity	7,973	12,303
AFG [Member]
Assets:
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	44	21
Xchange
Stockholders’ equity:
Redeemable Noncontrolling Interest, Equity, Carrying Amount		7
Variable Interest Entity [Member]
Assets:
Available-for-sale Securities	1,967	3,455
Restricted Cash	17	2
Loans, at fair value	1,829	2,718
Derivative and other assets	241	40
Derivative assets	239	38
Other assets	2	2
Total assets	4,054	6,216
Variable interest entity assets:
Loans, at fair value	1,829	2,718
Liabilities:
Long-term debt	3,107	4,216
Derivative liabilities	1,048	1,940
Other liabilities	5	0
Total liabilities	4,160	6,156
Stockholders’ equity:
Long-term Debt	2,788	4,056
Fixed Income Securities [Member]
Assets:
Available-for-sale Securities	1,395	1,730
Collateral Pledged [Member]
Assets:
Available-for-sale Securities	64	120
Short-term Investments	64	105
Collateral Pledged [Member] \| Fixed Income Securities [Member]
Assets:
Available-for-sale Securities	$ 0	$ 15

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Fixed income securities, amortized cost	$ 2,041
Short-term investments, amortized cost	507	$ 415
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Uncollectable premium receivables	5	9
Reinsurance Recoverable, Allowance for Credit Loss	$ 0	$ 0
Preferred stock, par value	$ 0.01
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred Stock, Shares Outstanding	0	0
Common stock, shares authorized	130,000,000	130,000,000
Common stock, shares issued	46,658,990	46,477,068
Common Stock, Shares, Outstanding	44,973,757
Treasury stock, shares	1,685,233	172,929
Fixed Income Securities [Member]
Fixed income securities, amortized cost	$ 1,469	$ 1,605
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Equity investments in pooled funds [Member]
Other Investment Not Readily Marketable, Fair Value	556	683
Collateral Pledged [Member]
Short-term investments, amortized cost	64	105
Collateral Pledged [Member] \| Fixed Income Securities [Member]
Fixed income securities, amortized cost	0	15
Short-term Investments [Member]
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Short-term Investments [Member] \| Collateral Pledged [Member] \| Fixed Income Securities [Member]
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Variable Interest Entity, Primary Beneficiary [Member]
Long-term Debt	2,788	4,056
Parent Company [Member]
Fixed income securities, amortized cost	13	130
Short-term investments, amortized cost	175	124
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	3
Parent Company [Member] \| Short-term Investments [Member]
Fixed income securities, amortized cost	$ 175	$ 124

Consolidated Statements of Tota

Consolidated Statements of Total Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenues:
Net premiums earned	$ 56	$ 47	$ 54
Insurance Commissions and Fees	31	26
Contractually Specified Servicing Fee, Late Fee, and Ancillary Fee Earned in Exchange for Servicing Financial Asset	3	0	0
Net investment income:
Securities available-for-sale and short-term	66	74	103
Net investment income	17	139	122
Realized Investment Gains (Losses)	31	7	22
Derivative, Gain (Loss) on Derivative, Net	129	22	(50)
Net realized gains on extinguishment of debt	81	33	0
Other income	10	1	3
Income (loss) on variable interest entities	21	7	5
Gain (Loss) Related to Litigation Settlement	126	0
Total revenues and other income	505	282	156
Policyholder Benefits and Claims Incurred, Net	(396)
Expenses:
Losses and loss adjustment expenses (benefit)		(88)	225
Deferred Policy Acquisition Costs, Amortization Expense	3	1	0
Insurance Commissions	18	15
Intangible amortization	47	55	57
General and Administrative Expense	141	111	92
Interest expense	168	187	222
Total expenses	(20)	281	596
Pretax income (loss)	525	2	(440)
Provision (benefit) for income taxes	2	18	(3)
Net income	522	(16)	(437)
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	(1)	(1)
Net income (loss) attributable to common stockholders	522	(17)	(437)
Other comprehensive income (loss), after tax
Net income	522	(16)	(437)
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, after Tax	0	(1)	1
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	(1)	(1)	(3)
Total other comprehensive income (loss), net of income tax	(310)	(21)	37
Total comprehensive income (loss), net of income tax	212	(38)	(400)
Less: net (gain) loss attributable to noncontrolling interest
Total comprehensive income (loss) attributable to common stockholders	$ 212	$ (38)	$ (400)
Basic	$ 11.48	$ (0.61)	$ (9.47)
Diluted	$ 11.31	$ (0.61)	$ (9.47)
Weighted Average Number of Shares Outstanding, Basic	45,719,906	46,535,001	46,147,062
Weighted Average Number of Shares Outstanding, Diluted	46,414,830	46,535,001	46,147,062
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest	$ (1)	$ (1)
AMPS Gain on Purchase of Shares	$ 1

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Accounting Standards Update 2016-13 [Member]	Retained Earnings [Member]	Retained Earnings [Member] Accounting Standards Update 2016-13 [Member]	AOCI Attributable to Parent [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Common Stock Held in Treasury, at Cost [Member]	Noncontrolling Interest [Member]	Parent Company [Member]	Parent Company [Member] Accounting Standards Update 2016-13 [Member]	Parent Company [Member] Retained Earnings [Member]	Parent Company [Member] Retained Earnings [Member] Accounting Standards Update 2016-13 [Member]	Parent Company [Member] AOCI Attributable to Parent [Member]	Parent Company [Member] Additional Paid-in Capital [Member]	Parent Company [Member] Common Stock Held in Treasury, at Cost [Member]
Beginning balance at Dec. 31, 2019	$ 1,536		$ 1,203		$ 42	$ 0	$ 0	$ 232	$ 0	$ 60
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	(400)		(437)		37						$ (400)		$ (437)		$ 37
Effect of New Accounting Principle		$ (4)		$ (4)								$ (4)		$ (4)
Stock-based compensation	11		0		0	0	0	11	0	0	11					$ 11
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(3)		(2)		0	0	0	0	(1)	0	(3)		(2)				$ (1)
Ending balance at Dec. 31, 2020	1,140		759		79	0	0	242	(1)	60
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	(38)		(17)		(21)						(38)		(17)		(21)
Stock-based compensation	14		0		0	0	0	14	0	0	14					14	0
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(6)		(4)		0	0	0	0	(2)	0	(6)		(4)				(2)
Ending balance at Dec. 31, 2021	1,098		726		58	0	0	257	(3)	60
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Noncontrolling Interest, Change in Redemption Value	(12)		(12)								(12)		(12)
Total comprehensive income (loss)	212		521		(310)						211		521		$ (310)
Stock-based compensation	17		0		0	0	0	17	0	0	17					$ 17
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(4)		(5)		0	0	0	0	2	0	(4)		(5)				$ 2
Treasury Stock, Value, Acquired, Cost Method	(14)								(14)
Ending balance at Dec. 31, 2022	1,305		1,245		$ (253)	$ 0	$ 0	$ 274	$ (15)	53
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest, Total, Excluding Gain on AMPS Repurchase	211
Noncontrolling Interest, Change in Redemption Value	3		3								3		3
AMPS Impact on Stockholders Equity	(8)		$ 1							(9)	$ 1		$ 1
Proceeds from Noncontrolling Interests	$ 2									$ 2

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income (loss) attributable to common stockholders	$ 522	$ (17)	$ (437)
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	(1)	(1)
AMPS Gain on Purchase of Shares	1
Net income	522	(16)	(437)
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation	2	2	1
Amortization of bond premium and discount	(11)	(13)	(15)
Share-based compensation	17	14	11
Unearned premiums, net	(58)	(82)	(48)
Losses and loss expenses, net	1,220	(147)	76
Ceded premiums payable	6	6	(3)
Premium receivables	54	48	44
Accrued interest payable	(134)	103	93
Amortization of intangible assets	47	55	57
Net investment gains (losses), including impairments	(31)	(7)	(22)
Net realized gains (losses) on extinguishment of debt	(81)	(33)	0
Income (loss) on variable interest entities	21	7	5
Increase (Decrease) in Derivative Assets and Liabilities	(44)	(23)	6
Other, net	(152)	(33)	67
Net cash provided by (used in) operating activities	1,335	(131)	(175)
Cash flows from investing activities:
Proceeds from sales of bonds	523	236	1,109
Proceeds from matured bonds	206	698	137
Purchases of bonds	(403)	(343)	(975)
Proceeds from sales of other invested assets	166	39	374
Purchases of other invested assets	(112)	(127)	(475)
Change in short-term investments	(52)	98	158
Change in cash collateral receivable	44	9	0
Proceeds From Financial Guaranty Variable Interest Entity Assets	504	171	178
Payments to Acquire Businesses, Net of Cash Acquired	(18)	0	(74)
Other, net	9	(5)	1
Net cash provided by investing activities	866	776	432
Cash flows from financing activities:
Proceeds from Sale of Senior Surplus Notes	0	11
Proceeds from Issuance of Secured Debt		1,163
Proceeds from (Payments to) Noncontrolling Interests	(1)	(1)
Paydown of Ambac Note		(1,641)	(121)
Payments of Debt Issuance Costs		(12)
Payments for Repurchase of Common Stock	(14.2)
Payment, Tax Withholding, Share-based Payment Arrangement	(4)	(6)	(3)
Paydown of Financial Guaranty Variable Interest Entity Liabilities	(591)	(170)	(178)
Net Cash Provided by (Used in) Financing Activities	(2,163)	(657)	(303)
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Continuing Operations	(1)	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	38	(12)	(46)
Supplemental disclosure of cash flow information
Income Taxes Paid	6	15	11
Cash payments related to reorganization items:
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	61	23	35
AMPS Exchange Cash Paid	(8)
Sitka AAC Note
Cash payments related to reorganization items:
Repayments of Secured Debt	1,210
5.1 % Surplus Notes Due 2020 [Member]
Cash payments related to reorganization items:
Payments for purchase of surplus notes	(191)
Tier 2 Notes [Member]
Cash payments related to reorganization items:
Repayments of Secured Debt	143
Ambac Financial Group, Inc Parent Company Only [Member]
Cash flows from operating activities:
Net income (loss) attributable to common stockholders	522	(17)	(437)
Net income	522	(17)	(437)
Adjustments to reconcile net income to net cash used in operating activities:
Amortization of bond premium and discount	(7)	(9)	(6)
Share-based compensation	12	14	11
Current income taxes	(1)	1	30
Net investment gains (losses), including impairments	14	5	1
Other, net	1	(6)	(10)
Net cash provided by (used in) operating activities	46	(10)	11
Cash flows from investing activities:
Proceeds from matured bonds	68	33	46
Purchases of bonds	(1)	(34)	(45)
Proceeds from sales of other invested assets	(4)	(8)	0
Change in short-term investments	(51)	105	89
Net cash provided by investing activities	12	95	16
Cash flows from financing activities:
Payments for Repurchase of Common Stock	(14)
Net Cash Provided by (Used in) Financing Activities	(57)	(92)	(29)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	1	(6)	(2)
Supplemental disclosure of cash flow information
Income Taxes Paid	$ 0	$ 0	$ 0

Background and Business Descrip

Background and Business Description	12 Months Ended
Background and Business Description	Dec. 31, 2022
Accounting Policies [Abstract]
Background and Business Description	1. BACKGROUND AND BUSINESS DESCRIPTION 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 business operations 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 have financial guarantee insurance portfolios that have been in runoff since 2008. AFS uses derivatives to hedge interest rate risk in AAC's insurance and investment portfolios. • Specialty Property and Casualty Insurance — Ambac's Specialty Property and Casualty Insurance program business includes five admitted carriers and an excess and surplus lines (“E&S” or “nonadmitted”) insurer (collectively, “Everspan”). Three of the five admitted carrier were acquired in 2022. Everspan carriers have an AM Best rating of 'A-' (Excellent). • Insurance Distribution — Ambac's specialty property and casualty ("P&C") insurance distribution business, which could include Managing General Agents and Underwriters (collectively "MGA/Us"), insurance wholesalers, and other distribution businesses, currently includes (i) Xchange Benefits, LLC (“Xchange”), a P&C MGA/U specializing in accident and health products, (ii) All Trans Risk Solutions, LLC ("All Trans"), a full service managing general underwriter specializing in commercial automobile insurance for specific "for-hire" auto classes, and (iii) Capacity Marine Corporation ("Capacity Marine"), a wholesale retail brokerage and reinsurance intermediary specializing in marine and international risk. Both All Trans and Capacity Marine Corporation were acquired in November 2022, refer to Note 4. Business Combination for further information relating to these acquisitions. Beginning in 2022, the Company began reporting these three business operations as segments; see Note 3. Segment Information for further information. Limitations on Voting and Transfer of Common Stock AFG’s Amended and Restated Certificate of Incorporation limits voting and transfer rights of stockholders in significant ways. Article IV contains voting restrictions applicable to any person owning at least 10% of AFG's common stock so that such person (including any group consisting of such person and any other person with whom such person or any affiliate or associate of such person has any agreement, contract, arrangement or understanding with respect to acquiring, voting, holding or disposing of AFG’s common stock) shall not be entitled to cast votes in excess of one vote less than 10% of the votes entitled to be cast by all common stock holders, except as otherwise approved by the OCI (as defined below). Article XII contains substantial restrictions on the ability to transfer AFG’s common stock. In order to preserve certain tax benefits, subject to limited exceptions, any attempted transfer of common stock shall be prohibited and void to the extent that, as a result of such transfer (or any series of transfers of which such transfer is a part), either (i) any person or group of persons shall become a holder of 5% or more of AFG’s common stock or (ii) the percentage stock ownership interest in AFG of any holder of 5% or more of AFG’s common stock shall be increased (a “Prohibited Transfer”). These restrictions shall not apply to an attempted transfer if the transferor or the transferee obtains the written approval of AFG’s Board of Directors to such transfer. A purported transferee of a Prohibited Transfer shall not be recognized as a stockholder of AFG for any purpose whatsoever in respect of the securities which are the subject of the Prohibited Transfer (the “Excess Securities”). Until the Excess Securities are acquired by another person in a transfer that is not a Prohibited Transfer, the purported transferee of a Prohibited Transfer shall not be entitled with respect to such Excess Securities to any rights of stockholders of AFG, including, without limitation, the right to vote such Excess Securities and to receive dividends or distributions, whether liquidating or otherwise, in respect thereof, if any. Once the Excess Securities have been acquired in a transfer that is not a Prohibited Transfer, the securities shall cease to be Excess Securities. If the Board determines that a transfer of securities constitutes a Prohibited Transfer then, upon written demand by AFG, the purported transferee shall transfer or cause to be transferred any certificate or other evidence of ownership of the Excess Securities within the purported transferee’s possession or control, together with any distributions paid by AFG with respect to such Excess Securities, to an agent designated by AFG. Such agent shall thereafter sell such Excess Securities and the proceeds of such sale shall be distributed as set forth in the Amended and Restated Certificate of Incorporation. If the purported transferee of a Prohibited Transfer has resold the Excess Securities before receiving such demand, such person shall be deemed to have sold the Excess Securities for AFG’s agent and shall be required to transfer to such agent the proceeds of such sale, which shall be distributed as set forth in the Amended and Restated Certificate of Incorporation. Strategies to Enhance Shareholder Value The Company's primary goal is to maximize long-term shareholder value through the execution of key strategies for its (i) Specialty Property and Casualty Insurance and Insurance Distribution businesses and (ii) Legacy Financial Guarantee Insurance. 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. Surplus Note Exchanges and Repurchases On January 19, 2021, AAC entered into a purchase agreement (the “Purchase Agreement”) with AFG and certain funds or accounts (the “Note Holders”), pursuant to which (i) the Note Holders agreed to sell to AAC all of the individual beneficial interests (the “Interests”) in the 5.1% senior notes due August 28, 2039 (the “Corolla Notes”), issued by the Corolla Trust, a Delaware statutory trust formed by AFG in 2014 (the "Corolla Trust")(see Note 12. Variable Interest Entities for a discussion of the establishment of the Corolla Trust), (ii) AFG agreed to sell to AAC the owner trust certificate for the Corolla Trust (the “Corolla Certificate”), which constituted all of the equity interests in the Corolla Trust, and (iii) AAC agreed to exchange the Interests and the Corolla Certificate for AAC’s surplus notes (collectively, the “Corolla Note Exchange”). The Note Holders held 100% of the outstanding Corolla Notes. Pursuant to the Purchase Agreement, each $1.00 principal amount of the Corolla Notes (and the associated amount of accrued and unpaid interest thereon) was exchanged for $0.9125 principal amount of surplus notes (and the associated amount of accrued and unpaid interest thereon) on the date of the consummation of the Corolla Note Exchange (the “Closing”). In addition, every $1.00 principal amount of the Corolla Certificate (and the associated amount of accrued and unpaid interest thereon) was exchanged for $0.64 principal amount of surplus notes (and the associated amount of accrued and unpaid interest thereon) on the date of Closing. The Closing occurred on January 22, 2021. At the Closing AAC issued $267 aggregate principal amount of surplus notes to consummate the Corolla Note Exchange and acquire all of the interests in the Corolla Trust. Subsequent to the closing the Corolla Trust was dissolved and the junior surplus note that had been deposited in the Corolla Trust by AFG in 2014 was canceled. In February 2021, AAC entered into a purchase agreement pursuant to which the holder of $15 principal amount of 5.1% junior surplus notes issued by AAC agreed to sell such notes to AAC in exchange for surplus notes (the "JSN Exchange"). Pursuant to the purchase agreement, each $1.00 principal amount of the junior surplus notes (and the associated amount of accrued and unpaid interest thereon) was exchanged for $0.8581 principal amount of surplus notes (and the associated amount of accrued and unpaid interest thereon). The closing of the JSN Exchange occurred on February 11, 2021, when AAC issued approximately $13 aggregate principal amount of surplus notes. Subsequent to the closing of the JSN Exchange the junior surplus notes were canceled. As a result of the Corolla Note Exchange and the JSN Exchange, AAC no longer has any junior surplus notes outstanding. The surplus notes exchanged pursuant to the Corolla Note Exchange and the JSN Exchange are part of the same series as, and rank equally with, the surplus notes previously issued by AAC. The Company recorded a gain of $33 for the year ended December 31, 2021, arising from AAC's purchases of junior surplus notes below their carrying values which is reported within Net realized gains (losses) on extinguishment of debt in the Consolidated Statements of Total Comprehensive Income (Loss). In addition, the Company recorded a gain of $4 for the year ended December 31, 2021, from the exchange of the Corolla Certificate held by AFG above its carrying value, which is reported within Net realized investment gains (losses) in the Consolidated Statements of Total Comprehensive Income (Loss). During 2022, AAC repurchased $266 current par of surplus notes from third party holders below the carrying value of the surplus notes including accrued interest, resulting in a gain of $134 which is reported within Net realized gains (losses) on extinguishment of debt in the Consolidated Statements of Total Comprehensive Income (Loss) for the year ended December 31, 2022. In addition, in November 2022, AAC purchased all of the remaining surplus notes received by AFG following execution of the Corolla Trust Purchase Agreement described above. AAC's repurchase of surplus notes from AFG had no impact on the consolidated financial statements of the Company. Puerto Rico Our financial guarantee insured exposure to Puerto Rico (the "Commonwealth") consisted of several different issuing entities (all below investment grade and whereby AAC has paid substantial claims since 2016) that have been part of the debt restructuring process under the Puerto Rico Oversight, Management, and Economic Stability Act (“PROMESA”), a U.S. federal law enacted in 2016 that, among other things, established a financial oversight board (the “FOMB”) and provided for a process for restructuring debt that roughly follows U.S. Bankruptcy laws. As of December 6, 2022, all AAC-insured Puerto Rico obligations have been restructured under PROMESA via court-approved plans of adjustment or qualifying modifications. Secured Note Refinancing On July 6, 2021, a newly formed variable interest entity and wholly-owned subsidiary of AFG, Sitka Holdings, LLC (“Sitka”), issued $1,175 par amount of LIBOR plus 4.5% senior secured notes due 2026 (the “Sitka Senior Secured Notes”). In connection with the issuance and sale of the Sitka Senior Secured Notes, AAC issued a secured note to Sitka in the same amount and with the same interest rate and maturity date as the Sitka Senior Secured Notes (the "Sitka AAC Note"). The proceeds from this offering of $1,163 were used to fund a portion of the full redemption of the Ambac LSNI Secured Notes due 2023 (the “LSNI Secured Notes”) and the secured note issued by AAC concurrently with the issuance of the LSNI Secured Notes (the "LSNI Ambac Note"). The remaining balance of the LSNI Secured Notes were redeemed utilizing other available temporary sources of liquidity. Ambac did not consolidate Sitka since it does not have a variable interest in the trust. Accordingly, the Sitka AAC Note was reported within Long-term debt on the Consolidated Balance Sheet. The Sitka AAC Note and the Sitka Senior Secured Notes were fully redeemed with the proceeds (net of reinsurance) of the BOA Settlement Payment from the BOA Parties (as such terms are defined below). Settlement of RMBS Litigations and Redemption of Secured Notes: Settlement of RMBS Litigations: In October 2022, AAC entered into a Settlement Agreement and Release (the “BOA Settlement Agreement”) with Bank of America Corporation and certain affiliates thereof (together, the “BOA Parties”) pursuant to which the BOA Parties paid AAC the sum of $1,840 (the “BOA Settlement Payment”) following the dismissal of AAC’s lawsuits against the BOA Parties concerning certain residential mortgage-backed securities (“RMBS”) trusts, and the withdrawal by AAC of its objections, including any pending appeals, concerning the settlements that were the subject of certain trust instructional proceedings. The BOA Settlement Payment received in October 2022 significantly reduced the subrogation recoverable asset on the Consolidated Balance Sheet. In exchange for the BOA Settlement Payment, AAC, on its own behalf and on behalf of its affiliates, agreed to release the BOA Parties and related parties (the “Released Parties”) from claims asserted or which could have been asserted in AAC’s pending litigations against the BOA Parties as well as claims that AAC and its affiliates ever had, may currently have or may have in the future against the Released Parties, subject to certain limited exceptions. The BOA Settlement Agreement also requires AAC to dismiss other pending claims against the Released Parties, and to generally refrain from, and in certain situations hold the Released Parties harmless with respect to, certain actions taken by AAC with respect to RMBS trusts created prior to the date of the BOA Settlement Agreement involving the Released Parties. The BOA Settlement Payment included recoveries from litigations for alleged breaches of contractual obligations and fraud by the BOA Parties. Management allocated the BOA Settlement Payment to each of the litigations based on previously developed valuations of each individual litigation. The portion of the BOA Settlement Payment allocated to fraud litigation recoveries has been recorded as a litigation recovery in the Statement of Comprehensive Income (Loss). On December 29, 2022, AAC entered into a Settlement Agreement and Release (the “Nomura Settlement Agreement”) with Nomura Credit & Capital, Inc. (“Nomura”) to settle its litigation against Nomura concerning certain RMBS trusts (the “Trusts”). Pursuant to the Nomura Settlement Agreement, Nomura made a cash payment to AAC of $140 (the "Nomura Settlement Payment"), and AAC and Nomura agreed to release each other and their respective affiliates and related persons from any claims relating to the Trusts, the financial guaranty policies issued by AAC in connection with Trusts (other than AAC’s obligations to pay insurance claims under such policies), the securities related to the Trusts, and the mortgage loans related to the Trusts. The Nomura Settlement Payment received in January 2023 will further reduce the subrogation recoverable asset on the Consolidated Balance Sheet. Redemption of Notes: During 2022 and 2023, AAC wholly redeemed its secured debt, in accordance with the terms of such debt, utilizing the BOA Settlement Payment, the Nomura Settlement Payment and other resources as follows: • Effective October 29, 2022, AAC wholly redeemed the Sitka AAC Note from the BOA Settlement Payment, for $1,218 (a price equal to 103% of the principal amount plus accrued and unpaid interest) and Sitka wholly redeemed the Sitka Senior Secured Notes for the same amount. Ambac recorded a loss of $53 reported in Net realized gains (losses) on extinguishment of debt in the Consolidated Statements of Total Comprehensive Income (Loss) for difference between the carrying value of the Sitka AAC Note and the redemption amount paid, excluding accrued interest. • Effective October 29, 2022, AAC applied Net Proceeds (as defined below) of approximately $213 from the BOA Settlement Payment to partially redeem Tier 2 Notes plus accrued and unpaid interest as of the date of redemption. The Tier 2 Notes were secured by proceeds from RMBS litigations net of reinsurance (“Net Proceeds”) in excess of $1,600 and were subject to mandatory redemption from Net Proceeds in excess of $1,600. • Effective January 15, 2023, AAC applied the Net Proceeds of $140 from the Nomura Settlement Payment plus approximately $6 from other sources to fully redeem the remaining Tier 2 Notes plus accrued and unpaid interest in the amount of approximately $146 as of the date of redemption. See Note 13. Long-term Debt in the Notes to the Consolidated Financial Statements included in Part II, Item 8 in this Annual Report on Form 10-K for the year ended December 31, 2022, for a description of Sitka, the Sitka AAC Note, the Sitka Senior Secured Notes and the Tier 2 Notes. AAC also invested a portion of its assets in the Sitka Senior Secured Notes, reported as Fixed maturity securities - available-for-sale on the Consolidated Balance Sheet and recorded a realized investment gain of $5 in the Consolidated Statements of Total Comprehensive Income (Loss) on the redemption date. Impact to the Consolidated Statement of Comprehensive Income (Loss): The total gain recognized in net income attributable to common stockholders related to entering into the BOA Settlement Agreement and the Nomura Settlement Agreement, including the redemption of the Sitka AAC Note following the BOA Settlement, was as follows: Third Fourth Full Losses and loss benefit (1) $ 319 $ 43 $ 362 Litigation recoveries — 126 126 Net realized gains (losses) on extinguishment of debt — (53) (53) Net investment gains (losses), including impairments — 5 5 Impact to net income attributable to common stockholders $ 319 $ 121 $ 440 (1) Full year 2022 losses and loss benefit relating to R&W recoveries were $123.
Settlement of RMBS Litigation and Redemption of Secured Notes	Settlement of RMBS Litigations and Redemption of Secured Notes: Settlement of RMBS Litigations: In October 2022, AAC entered into a Settlement Agreement and Release (the “BOA Settlement Agreement”) with Bank of America Corporation and certain affiliates thereof (together, the “BOA Parties”) pursuant to which the BOA Parties paid AAC the sum of $1,840 (the “BOA Settlement Payment”) following the dismissal of AAC’s lawsuits against the BOA Parties concerning certain residential mortgage-backed securities (“RMBS”) trusts, and the withdrawal by AAC of its objections, including any pending appeals, concerning the settlements that were the subject of certain trust instructional proceedings. The BOA Settlement Payment received in October 2022 significantly reduced the subrogation recoverable asset on the Consolidated Balance Sheet. In exchange for the BOA Settlement Payment, AAC, on its own behalf and on behalf of its affiliates, agreed to release the BOA Parties and related parties (the “Released Parties”) from claims asserted or which could have been asserted in AAC’s pending litigations against the BOA Parties as well as claims that AAC and its affiliates ever had, may currently have or may have in the future against the Released Parties, subject to certain limited exceptions. The BOA Settlement Agreement also requires AAC to dismiss other pending claims against the Released Parties, and to generally refrain from, and in certain situations hold the Released Parties harmless with respect to, certain actions taken by AAC with respect to RMBS trusts created prior to the date of the BOA Settlement Agreement involving the Released Parties. The BOA Settlement Payment included recoveries from litigations for alleged breaches of contractual obligations and fraud by the BOA Parties. Management allocated the BOA Settlement Payment to each of the litigations based on previously developed valuations of each individual litigation. The portion of the BOA Settlement Payment allocated to fraud litigation recoveries has been recorded as a litigation recovery in the Statement of Comprehensive Income (Loss). On December 29, 2022, AAC entered into a Settlement Agreement and Release (the “Nomura Settlement Agreement”) with Nomura Credit & Capital, Inc. (“Nomura”) to settle its litigation against Nomura concerning certain RMBS trusts (the “Trusts”). Pursuant to the Nomura Settlement Agreement, Nomura made a cash payment to AAC of $140 (the "Nomura Settlement Payment"), and AAC and Nomura agreed to release each other and their respective affiliates and related persons from any claims relating to the Trusts, the financial guaranty policies issued by AAC in connection with Trusts (other than AAC’s obligations to pay insurance claims under such policies), the securities related to the Trusts, and the mortgage loans related to the Trusts. The Nomura Settlement Payment received in January 2023 will further reduce the subrogation recoverable asset on the Consolidated Balance Sheet. Redemption of Notes: During 2022 and 2023, AAC wholly redeemed its secured debt, in accordance with the terms of such debt, utilizing the BOA Settlement Payment, the Nomura Settlement Payment and other resources as follows: • Effective October 29, 2022, AAC wholly redeemed the Sitka AAC Note from the BOA Settlement Payment, for $1,218 (a price equal to 103% of the principal amount plus accrued and unpaid interest) and Sitka wholly redeemed the Sitka Senior Secured Notes for the same amount. Ambac recorded a loss of $53 reported in Net realized gains (losses) on extinguishment of debt in the Consolidated Statements of Total Comprehensive Income (Loss) for difference between the carrying value of the Sitka AAC Note and the redemption amount paid, excluding accrued interest. • Effective October 29, 2022, AAC applied Net Proceeds (as defined below) of approximately $213 from the BOA Settlement Payment to partially redeem Tier 2 Notes plus accrued and unpaid interest as of the date of redemption. The Tier 2 Notes were secured by proceeds from RMBS litigations net of reinsurance (“Net Proceeds”) in excess of $1,600 and were subject to mandatory redemption from Net Proceeds in excess of $1,600. • Effective January 15, 2023, AAC applied the Net Proceeds of $140 from the Nomura Settlement Payment plus approximately $6 from other sources to fully redeem the remaining Tier 2 Notes plus accrued and unpaid interest in the amount of approximately $146 as of the date of redemption. See Note 13. Long-term Debt in the Notes to the Consolidated Financial Statements included in Part II, Item 8 in this Annual Report on Form 10-K for the year ended December 31, 2022, for a description of Sitka, the Sitka AAC Note, the Sitka Senior Secured Notes and the Tier 2 Notes. AAC also invested a portion of its assets in the Sitka Senior Secured Notes, reported as Fixed maturity securities - available-for-sale on the Consolidated Balance Sheet and recorded a realized investment gain of $5 in the Consolidated Statements of Total Comprehensive Income (Loss) on the redemption date. Impact to the Consolidated Statement of Comprehensive Income (Loss): The total gain recognized in net income attributable to common stockholders related to entering into the BOA Settlement Agreement and the Nomura Settlement Agreement, including the redemption of the Sitka AAC Note following the BOA Settlement, was as follows: Third Fourth Full Losses and loss benefit (1) $ 319 $ 43 $ 362 Litigation recoveries — 126 126 Net realized gains (losses) on extinguishment of debt — (53) (53) Net investment gains (losses), including impairments — 5 5 Impact to net income attributable to common stockholders $ 319 $ 121 $ 440 (1) Full year 2022 losses and loss benefit relating to R&W recoveries were $123.
Surplus Note Exchanges and Repurchases	Surplus Note Exchanges and Repurchases On January 19, 2021, AAC entered into a purchase agreement (the “Purchase Agreement”) with AFG and certain funds or accounts (the “Note Holders”), pursuant to which (i) the Note Holders agreed to sell to AAC all of the individual beneficial interests (the “Interests”) in the 5.1% senior notes due August 28, 2039 (the “Corolla Notes”), issued by the Corolla Trust, a Delaware statutory trust formed by AFG in 2014 (the "Corolla Trust")(see Note 12. Variable Interest Entities for a discussion of the establishment of the Corolla Trust), (ii) AFG agreed to sell to AAC the owner trust certificate for the Corolla Trust (the “Corolla Certificate”), which constituted all of the equity interests in the Corolla Trust, and (iii) AAC agreed to exchange the Interests and the Corolla Certificate for AAC’s surplus notes (collectively, the “Corolla Note Exchange”). The Note Holders held 100% of the outstanding Corolla Notes. Pursuant to the Purchase Agreement, each $1.00 principal amount of the Corolla Notes (and the associated amount of accrued and unpaid interest thereon) was exchanged for $0.9125 principal amount of surplus notes (and the associated amount of accrued and unpaid interest thereon) on the date of the consummation of the Corolla Note Exchange (the “Closing”). In addition, every $1.00 principal amount of the Corolla Certificate (and the associated amount of accrued and unpaid interest thereon) was exchanged for $0.64 principal amount of surplus notes (and the associated amount of accrued and unpaid interest thereon) on the date of Closing. The Closing occurred on January 22, 2021. At the Closing AAC issued $267 aggregate principal amount of surplus notes to consummate the Corolla Note Exchange and acquire all of the interests in the Corolla Trust. Subsequent to the closing the Corolla Trust was dissolved and the junior surplus note that had been deposited in the Corolla Trust by AFG in 2014 was canceled. In February 2021, AAC entered into a purchase agreement pursuant to which the holder of $15 principal amount of 5.1% junior surplus notes issued by AAC agreed to sell such notes to AAC in exchange for surplus notes (the "JSN Exchange"). Pursuant to the purchase agreement, each $1.00 principal amount of the junior surplus notes (and the associated amount of accrued and unpaid interest thereon) was exchanged for $0.8581 principal amount of surplus notes (and the associated amount of accrued and unpaid interest thereon). The closing of the JSN Exchange occurred on February 11, 2021, when AAC issued approximately $13 aggregate principal amount of surplus notes. Subsequent to the closing of the JSN Exchange the junior surplus notes were canceled. As a result of the Corolla Note Exchange and the JSN Exchange, AAC no longer has any junior surplus notes outstanding. The surplus notes exchanged pursuant to the Corolla Note Exchange and the JSN Exchange are part of the same series as, and rank equally with, the surplus notes previously issued by AAC. The Company recorded a gain of $33 for the year ended December 31, 2021, arising from AAC's purchases of junior surplus notes below their carrying values which is reported within Net realized gains (losses) on extinguishment of debt in the Consolidated Statements of Total Comprehensive Income (Loss). In addition, the Company recorded a gain of $4 for the year ended December 31, 2021, from the exchange of the Corolla Certificate held by AFG above its carrying value, which is reported within Net realized investment gains (losses) in the Consolidated Statements of Total Comprehensive Income (Loss). During 2022, AAC repurchased $266 current par of surplus notes from third party holders below the carrying value of the surplus notes including accrued interest, resulting in a gain of $134 which is reported within Net realized gains (losses) on extinguishment of debt in the Consolidated Statements of Total Comprehensive Income (Loss) for the year ended December 31, 2022. In addition, in November 2022, AAC purchased all of the remaining surplus notes received by AFG following execution of the Corolla Trust Purchase Agreement described above. AAC's repurchase of surplus notes from AFG had no impact on the consolidated financial statements of the Company. Puerto Rico Our financial guarantee insured exposure to Puerto Rico (the "Commonwealth") consisted of several different issuing entities (all below investment grade and whereby AAC has paid substantial claims since 2016) that have been part of the debt restructuring process under the Puerto Rico Oversight, Management, and Economic Stability Act (“PROMESA”), a U.S. federal law enacted in 2016 that, among other things, established a financial oversight board (the “FOMB”) and provided for a process for restructuring debt that roughly follows U.S. Bankruptcy laws. As of December 6, 2022, all AAC-insured Puerto Rico obligations have been restructured under PROMESA via court-approved plans of adjustment or qualifying modifications. Secured Note Refinancing On July 6, 2021, a newly formed variable interest entity and wholly-owned subsidiary of AFG, Sitka Holdings, LLC (“Sitka”), issued $1,175 par amount of LIBOR plus 4.5% senior secured notes due 2026 (the “Sitka Senior Secured Notes”). In connection with the issuance and sale of the Sitka Senior Secured Notes, AAC issued a secured note to Sitka in the same amount and with the same interest rate and maturity date as the Sitka Senior Secured Notes (the "Sitka AAC Note"). The proceeds from this offering of $1,163 were used to fund a
Strategies to Enhance Shareholder Vakye	Strategies to Enhance Shareholder Value The Company's primary goal is to maximize long-term shareholder value through the execution of key strategies for its (i) Specialty Property and Casualty Insurance and Insurance Distribution businesses and (ii) Legacy Financial Guarantee Insurance. 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)	12 Months Ended
	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Significant Accounting Policies	2. BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES Ambac’s consolidated financial statements have been prepared on the basis of U.S. generally accepted accounting principles (“GAAP”). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses and disclosures. Such estimates that are particularly susceptible to change are used in connection with certain fair value measurements, valuation of financial guarantee loss reserves for non-derivative insurance policies and the valuation allowance on the deferred tax asset, any of which individually could be material. 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. The usual condition for a controlling financial interest is ownership of a majority of the voting interests of an entity. However, a controlling financial interest may also exist in entities, such as VIEs, through arrangements that do not involve controlling voting interests. A VIE is an entity: a) that lacks enough equity investment at risk to permit the entity to finance its activities without additional subordinated financial support from other parties; or b) where the group of equity holders does not have: (1) the power, through voting rights or similar rights, to direct the activities of an entity that most significantly impact the entity’s economic performance; (2) the obligation to absorb the entity’s expected losses; or (3) the right to receive the entity’s expected residual returns. The determination of whether a variable interest holder is the primary beneficiary involves performing a qualitative analysis of the VIE that includes, among other factors, its capital structure, contractual terms including the rights of each variable interest holder, the activities of the VIE, whether the variable interest holder has the power to direct the activities of a VIE that most significantly impact the VIE’s economic performance, whether the variable interest holder has the obligation to absorb losses of the VIE that could potentially be significant to the VIE or the right to receive benefits from the VIE that could potentially be significant to the VIE, related party relationships and the design of the VIE. An entity that is deemed the primary beneficiary of a VIE is required to consolidate the VIE. Refer to Note 12. 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. AFG Unconsolidated Financial Information Financial information of AFG is presented in Schedule II in this Annual Report on Form 10-K as of December 31, 2022 and 2021 and for the years ended December 31, 2022, 2021 and 2020. Investments in subsidiaries are accounted for using the equity method of accounting in Schedule II. Measurement of Credit Losses on Financial Instruments (CECL) Ambac measures credit losses on financial assets that are not accounted for at fair value through net income in accordance with the Current Expected Credit Loss standard or "CECL". The CECL impact on available-for-sale debt securities is discussed in the Investments sub-section below. The CECL impact on amortized cost assets is addressed in the Premium, Reinsurance Recoverables and Loan sub-sections below. These amortized cost assets reflect management's current estimate of all expected lifetime credit losses. The estimate of expected lifetime credit losses considers historical information, current information, as well as reasonable and supportable forecasts. Expected lifetime credit losses for amortized cost assets are recorded as an allowance for credit losses, with subsequent increases or decreases in the allowance reflected in net income each period. CECL does not apply to subrogation recoveries of previously paid and unpaid losses on insurance contracts accounted for under ASC 944 nor does it apply to equity method investments accounted for under ASC 323. Investments The Investments - Debt Securities Topic of the ASC requires that all debt instruments be classified in Ambac’s Consolidated Balance Sheets according to their purpose and, depending on that classification, be carried at either cost or fair market value. Ambac’s non-VIE debt investment portfolio is accounted for on a trade-date basis and consists primarily of: • Investments in fixed maturity securities are either classified as available-for-sale or trading as defined by the Investments - Debt Securities Topic of the ASC. Available-for-sale debt securities are reported in the financial statements at fair value with unrealized gains and losses, net of deferred taxes, reflected in Accumulated Other Comprehensive Income (Loss) in Stockholders’ Equity and computed using amortized cost as the basis. For purposes of computing amortized cost, premiums and discounts are accounted for using the effective interest method over the term of the security. For structured debt securities with a large underlying pool of homogenous loans, such as mortgage-backed and asset-backed securities, premiums and discounts are adjusted for the effects of actual and anticipated prepayments. For other fixed maturity securities, such as corporate and municipal bonds, discounts are amortized or accreted over the remaining term of the securities and premiums are amortized to the earliest call date. Investments in fixed maturity securities classified at trading are reported in the financial statements at fair value with unrealized gains and losses included in Net investment income on the Statement of Total Comprehensive Income (Loss). • Equity interests in pooled investment funds which are accounted for in accordance with the Investments - Equity Securities Topic of the ASC and reported as Other investments on the Consolidated Balance Sheet with income reported through Net investment income on the Statement of Total Comprehensive Income (Loss). Equity interests in the form of common stock or in-substance common stock are classified as trading securities and reported at fair value while limited partner interests in such funds are reported using the equity method. • Preferred equity investments that do not have readily determinable fair values and are carried at cost, less any impairments as permitted under the Investments — Equity Securities Topic of the ASC. VIE investments in fixed maturity securities are carried at fair value as they are classified as either available-for-sale or trading as defined by the Investments — Debt Securities Topic of the ASC, or accounted for under the fair value option election. For additional information about VIE investments, including fair value by asset-type, see Note 12. Variable Interest Entities . Fair value is based primarily on quotes obtained from independent market sources. When quotes for fixed maturity securities are not available or cannot be reasonably corroborated, valuation models are used to estimate fair value. These models include estimates, made by management, which utilize current market information. When fair value is not readily determinable for pooled investment funds, the investments are valued using net asset value ("NAV") as a practical expedient as permitted under the Fair Value Measurement Topic of the ASC. Investment valuations could differ materially from amounts that would actually be realized in the market. Realized gains and losses on the sale of investments are determined on the basis of specific identification. Refer to Note 6. Fair Value Measurements for further description of the methodologies used to determine the fair value of investments, including model inputs and assumptions where applicable. Ambac has a formal credit impairment review process for fixed maturity available-for-sale securities in its investment portfolio. Ambac conducts a review each quarter to identify and evaluate investments that have indications of impairment in accordance with the Investments - Debt Securities Topic of the ASC. Under CECL, factors considered to identify and assess securities for other than temporary impairment included: (i) fair values that have declined by 20% or more below amortized cost; (ii) recent downgrades by rating agencies; (iii) the financial condition of the issuer and financial guarantor, as applicable, and an analysis of projected defaults on the underlying collateral; (iv) whether scheduled interest payments are past due; (v) whether Ambac has the intent to sell the security; and (vi) whether it is more likely than not that Ambac will be required to sell a security before the anticipated recovery of its amortized cost basis. The recognition of credit impairment losses for available-for-sale debt securities are recorded as an allowance for credit losses with an offsetting charge to net income. Improvements to estimated credit losses for available-for-sale debt securities are recognized immediately in net income. If we believe a decline in the fair value of a particular fixed maturity available-for-sale investment is not credit impaired, we record the decline as an unrealized loss net of tax in Accumulated Other Comprehensive Income (Loss) in Stockholders’ Equity on our Consolidated Balance Sheets. If management either: (i) has the intent to sell its investment in a debt security or (ii) determines that the Company more likely than not will be required to sell the debt security before its anticipated recovery of the amortized cost basis less any current period credit impairment, then an impairment charge is recognized in earnings, with the amortized cost of the security written-down to fair value. The evaluation of securities for credit impairment is a quantitative and qualitative process, which is subject to risks and uncertainties and is intended to determine whether, and to what extent, declines in the fair value of investments should be recognized in current period earnings. The risks and uncertainties include changes in general economic conditions, the issuer’s or guarantor’s financial condition and/or future prospects, the impact of regulatory actions on the investment portfolio, the performance of the underlying collateral, the effects of changes in interest rates or credit spreads and the expected recovery period. With respect to Ambac insured securities owned, future cash flows used to measure credit impairment represents the sum of (i) the bond’s intrinsic cash flows and (ii) the estimated AAC claim payments. Ambac’s assessment about whether a decline in value is considered a credit impairment reflects management’s current judgment regarding facts and circumstances specific to a security and the factors noted above. If that judgment changes, Ambac may ultimately record a charge for credit impairment in future periods. Ambac has made certain accounting policy elections related to accrued interest receivable ("AIR") for available-for-sale investments under CECL. Elections include: i) not measuring AIR for credit impairment, instead AIR is written off when it becomes 90 days past due; ii) writing off AIR by reversing interest income; iii) presenting AIR separately in Other Assets on the balance sheet and iv) excluding AIR from amortized cost balances in required CECL disclosures found in Note 5. Investments. AIR at December 31, 2022 and 2021 was $10 and $10, respectively. Refer to Note 5. Investments for further credit impairment disclosures. Premiums Legacy Financial Guarantee Insurance: Gross premiums were received either upfront or in installments. For premiums received upfront, an unearned premium revenue (“UPR”) liability was established, which was initially recorded as the cash amount received. For installment premium transactions, a premium receivable asset and offsetting UPR liability was initially established in an amount equal to: (i) the present value of future contractual premiums due (the “contractual” method) or (ii) if the underlying insured obligation is a homogenous pool of assets which are contractually prepayable, the present value of premiums to be collected over the expected life of the transaction (the “expected” method). An appropriate risk-free rate corresponding to the weighted average life of each policy and currency is used to discount the future premiums contractually due or expected to be collected. For example, U.S. dollar exposures are discounted using U.S. Treasury rates while exposures denominated in a foreign currency are discounted using the appropriate risk-free rate for the respective currency. The weighted average risk-free rate at December 31, 2022 and 2021, was 3.0%. and 2.2%, respectively, and the weighted average period of future premiums used to estimate the premium receivable at December 31, 2022 and 2021, was 8.0 years and 8.0 years, respectively. Insured obligations consisting of homogeneous pools for which Ambac uses expected future premiums to estimate the premium receivable include residential mortgage-backed securities ("RMBS"). As prepayment assumptions change for homogenous pool transactions, or if there is an actual prepayment for a “contractual” method installment transaction, the related premium receivable and UPR are adjusted in equal and offsetting amounts with no immediate effect on earnings using new premium cash flows and the then current risk-free rate corresponding to the initial weighted average life of the related policy. For both upfront and installment premium policies, premium revenues are earned over the life of the financial guarantee contract in proportion to the insured principal amount outstanding at each reporting date (referred to as the level-yield method). For installment paying policies, the premium receivable discount, equating to the difference between the undiscounted future installment premiums and the present value of future installment premiums, is accreted as premiums earned in proportion to the premium receivable balance at each reporting date. When a bond issue insured by Ambac has been retired early, typically due to an issuer call, any remaining UPR is recognized at that time to the extent the financial guarantee contract is legally extinguished, causing accelerated premium revenue. For installment premium paying transactions, we offset the recognition of any remaining UPR by the reduction of the related premium receivable to zero (as it will not be collected as a result of the retirement), which may cause negative accelerated premium revenue. Certain obligations insured by Ambac have been legally defeased whereby government securities are purchased by the issuer with the proceeds of a new bond issuance, or less frequently with other funds of the issuer, and held in escrow. The principal and interest received from the escrowed securities are then used to retire the Ambac-insured obligations at a future date either to their maturity date (a refunding) or a specified call date (a pre-refunding). Ambac has evaluated the provisions in policies issued on these obligations and determined those insurance policies have not been legally extinguished. For policies with refunding securities, premium revenue recognition is not impacted as the escrowed maturity date is the same as the previous legal maturity date. For policies with pre-refunding securities, the maturity date of the pre-refunded security has been shortened from its previous legal maturity. Although premium revenue recognition has not been accelerated in the period of the pre-refunding, it results in an increase in the rate at which the policy's remaining UPR is to be recognized. For financial guarantee contracts, the issuer's ability and willingness to pay its insured debt obligation impacts the payment of policy losses by Ambac as well as the receipt of premiums from the issuer. As such, management leverages its existing loss reserve estimation process to evaluate credit impairment for premium receivables. Key factors in assessing credit impairment include historical premium collection data, internal risk classifications, credit ratings and loss severities. For structured finance transactions involving special purpose entities, we further evaluate the priority of premiums paid to Ambac within the contractual waterfall, as required by bond indentures. Ambac has a formal quarterly credit impairment review process for premium receivables. Under CECL, management utilizes either a discounted cash flow ("DCF") or probability of default/loss given default ("PD/LGD") approach to estimate credit impairment. The DCF approach utilizes expected cash flows developed by Ambac's Risk Management Group using the same (or similar) models used for estimating loss reserves where such models can identify shortfalls in premiums. Credit impairment using the DCF approach is equal to the difference between amortized cost and the present value of expected cash flows. Credit impairment under the PD/LGD approach is the product of (i) the premium receivable carrying value, (ii) internally developed default probability (considering internal ratings and average life), and (iii) internally developed loss severities. Refer to Note 8. Insurance Contracts for further credit impairment disclosures. AAC has reinsurance in place pursuant to surplus share treaties and facultative reinsurance agreements. Similar to gross premiums, premiums ceded to reinsurers were paid either upfront or in installments. For premiums paid upfront, a deferred ceded premium asset was established which is initially recorded as the cash amount paid. For installment premiums, a ceded premiums payable liability and offsetting deferred ceded premium asset were initially established in an amount equal to: i) the present value of future contractual premiums due or ii) if the underlying insured obligation is a homogenous pool of assets, the present value of expected premiums to be paid over the life of the transaction. An appropriate risk-free rate corresponding to the weighted average life of each policy and exposure currency is used to discount the future premiums contractually due or expected to be collected. Premiums ceded to reinsurers reduce the amount of premiums earned by Ambac from its financial guarantee insurance policies. For both upfront and installment premiums, ceded premiums written are primarily recognized in earnings in proportion to and at the same time as the related gross premium revenue is recognized. For premiums paid to reinsurers on an installment basis, Ambac records the present value of future ceding commissions as an offset to ceded premiums payable, using the same assumptions noted above for installment premiums. Specialty Property and Casualty Insurance: Gross written premiums on insurance policies are recorded at the inception of the policy and can be received on an upfront or installment basis. Ceded premiums written are based on contractual terms applied against related gross written premiums. Premiums, net of reinsurance, are recognized as revenue on a daily pro-rata basis over the term of the insured risk. Unearned premiums and Deferred ceded premiums represents the portion of gross and ceded premiums written that relate to unexpired risk, respectively. Premium receivables represent balances currently due and amounts not yet due from policyholders, managing general agents or producers issuing insurance policies on Everspan's behalf. Premium receivables are reported net of an allowance for expected lifetime credit losses. The allowance is based upon Everspan's ongoing review of amounts outstanding, including delinquencies and write-offs, and other relevant factors. Credit risk is partially mitigated by the managing general agent's ability to cancel the policy on behalf of Everspan if the policyholder does not pay the premium, thereby reducing the related policy's premium written and Everspan's premium receivable. Loans Loans are reported at either their outstanding principal balance less unamortized discount or at fair value. • Loans not held by consolidated VIEs are reported at their outstanding principal balance less unamortized discount and are reported within Other assets on the Consolidated Balance Sheet. Interest income is earned using the effective interest method based upon interest accrued on the unpaid principal balance adjusted for accretion of discounts. A loan is considered impaired when, based on the financial condition of the borrower, it is probable that Ambac will be unable to collect all principal and interest due according to the contractual terms of the loan agreement. Ambac has a formal quarterly credit impairment review process for these loans. The key factors in assessing credit impairment are internal credit ratings and loss severities. Management utilizes a PD/LGD approach, similar to the one described above for financial guarantee premium receivables, which is applied to the loan carrying value. • Loans held by VIEs consolidated as required under the Consolidation Topic of the ASC are carried at fair value under the fair value option election with changes in fair value recorded in Income (loss) on variable interest entities on the Consolidated Statements of Total Comprehensive Income (Loss). Such loans are reported as Loans, at fair value within the Variable interest entity assets section of the Consolidated Balance Sheet. Derivative Contracts The Company has entered into derivative contracts primarily to hedge certain economic risks inherent in its asset and liability portfolios. None of Ambac’s derivative contracts are designated as hedges under the Derivatives and Hedging Topic of the ASC. Ambac's derivatives consist primarily of interest rate swaps and futures contracts. • Ambac maintains a portfolio consisting primarily of interest rate swaps and futures contracts to economically hedge interest rate risk in the financial guarantee and investment portfolios. While this portfolio also includes certain legacy interest rate swaps executed in connection with financial guarantee client financings, the interest rate derivatives portfolio is managed on the basis of its net sensitivity to changes in interest rates. Changes in the fair value of these interest rate derivatives are recorded, along with changes in fair value of other derivative contracts, within Net gains (losses) on derivative contracts on the Consolidated Statements of Total Comprehensive Income (Loss). • VIEs consolidated under the Consolidation Topic of the ASC entered into derivative contracts to meet specified purposes within their securitization structure. Changes in fair value of consolidated VIE derivatives are included within Income (loss) on variable interest entities on the Consolidated Statements of Total Comprehensive Income (Loss). All derivatives are recorded on the Consolidated Balance Sheets at fair value on a gross basis; assets and liabilities are netted by counterparty only when a legal right of offset exists. Variation payments on centrally cleared swaps and futures contracts are considered settlements of the associated derivative balances and are reflected as a reduction to derivative liabilities or assets on the Consolidated Balance Sheets. For other derivatives, Ambac has determined that the amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral may not be used to offset amounts due under the derivative instruments in the normal course of settlement. Therefore, such amounts are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement and are included in Other assets on the Consolidated Balance Sheets. Refer to Note 10. Derivative Instruments for further discussion of the Company’s use of derivative instruments and their impact of the consolidated financial statements. Refer to Note 6. Fair Value Measurements for further description of the methodologies used to determine the fair value of derivative contracts, including model inputs and assumptions where applicable. Deferred Acquisition Costs, Ceding Commissions and Deferred Program Fees The Specialty Property and Casualty Program business defers acquisition costs incurred that are related directly to the successful acquisition of new or renewal insurance contracts, including commissions paid to managing general agents. Ceding commissions received from reinsurers represent a recovery of related acquisition costs. Deferred acquisition costs, net of ceding commissions, are amortized over the related policy period, generally one year, and recognized in amortization of deferred acquisition costs. Ceding commissions received in excess of the related direct acquisition costs are deferred and amortized over the related policy period, and recognized as program fees. Goodwill Goodwill is attributable to acquisitions, discussed in Note 4. Business Combination and represents the acquisition cost in excess of the fair value of net assets acquired, including identifiable intangible assets. Goodwill is assigned at acquisition to the applicable reporting unit of the acquired entity giving rise to the goodwill. Goodwill is not amortized but is subject to impairment testing. Goodwill impairment tests are performed annually or more frequently if circumstances indicate a possible impairment. Ambac tests goodwill for impairment as of October 1st of each year. If, after assessing qualitative factors, management believes it is more likely than not that the fair value of a reporting unit is less than its carrying amount, a quantitative impairment evaluation is performed. Management also has the option to bypass the qualitative evaluation and proceed directly to the quantitative evaluation. The quantitative test compares the estimated fair value of the reporting unit with its carrying value (including goodwill and identifiable intangible assets). An impairment is recognized for the excess of the carrying amount of the reporting unit over it estimated fair value. If the reporting unit’s estimated fair value exceeds its carrying value, goodwill is not impaired. There have been no accumulated impairment losses since goodwill was established. Intangible Assets Financial Guarantee Insurance intangible: Upon Ambac's emergence from bankruptcy in 2013, an insurance intangible asset was recorded which represented the difference between the fair value and aggregate carrying value of the financial guarantee insurance and reinsurance assets and liabilities. The carrying values of financial guarantee insurance and reinsurance contracts continue to be reported and measured in accordance with their existing accounting policies. Pursuant to the Financial Services-Insurance Topic of the ASC, the insurance intangible is to be measured on a basis consistent with the related financial guarantee insurance and reinsurance contracts. The initial insurance intangible asset was assigned to groups of insurance and reinsurance contracts with similar characteristics and has been amortized using a level-yield method based on par exposure of the related groups. Finite-lived intangibles: Ambac acquired identifiable intangible assets attributable to the Xchange, All Trans and Capacity Marine acquisitions further discussed in Note 4. Business Combination . The intangible assets primarily relate to distribution relationships, non-compete agreements and trade names, all of which have finite lives and are amortized over their estimated useful lives using the straight- line method. The Company tests finite-lived acquired intangible assets for impairment if certain events occur or circumstances change indicating that the carrying amount of the intangible asset may not be recoverable. The carrying amount of the intangible asset is not recoverable if it exceeds the projected undiscounted cash flows expected to result from the use and eventual disposal of the asset or asset group. If deemed unrecoverable, an impairment loss is recognized for the excess carrying amount over the fair value. There have been no accumulated impairment losses since these finite-lived intangible assets were established. Indefinite-lived intangibles Ambac acquired identifiable intangible assets attributable to its acquisitions of admitted carriers in both 2021 and 2022, which were accounted for as asset acquisitions. The intangible assets relate to insurance licenses which have indefinite lives and therefore are not amortized. The useful lives are re-evaluated each period to determine whether facts and circumstances continue to support an indefinite life. The Company tests indefinite-lived acquired intangible assets for impairment annually or more frequently if circumstances indicate a possible impairment. Ambac tests indefinite-lived intangibles for impairment as of October 1st of each year. If, after assessing qualitative factors, management believes it is more likely than not that the intangible assets are impaired, a quantitative impairment evaluation is performed. Management also has the option to bypass the qualitative evaluation and proceed directly to the quantitative evaluation. The quantitative test compares the estimated fair value of the intangible asset with its carrying value. An impairment is recognized for the excess of the carrying amount of the intangible asset over it estimated fair value. If the asset’s estimated fair value exceeds its carrying value, the intangible asset is not impaired. There have been no accumulated impairment losses since these indefinite-lived intangible assets were established. Restricted Cash Cash that we do not have the right to use for general purposes is recorded as restricted cash in our consolidated balance sheets. Restricted cash includes (i) consolidated variable interest entity cash restricted to support the obligations of the consolidated VIEs and (ii) fiduciary cash held by Ambac's insurance distribution subsidiaries as described below. Fiduciary Funds: As an intermediary, we hold funds, generally in a fiduciary capacity, for the account of third parties, typically as the result of premiums received from retail brokers or insureds that are in transit to insurers and claims due that are in transit from insurers. Since fiduciary assets are not available for corporate use, they are shown in the consolidated balance sheets as restricted cash and we present an equal and corresponding fiduciary liability relating to these funds representing amounts or claims or premiums due on our consolidated balance sheets (included in Other liabilities). Fiduciary funds are generally required to be kept in bank accounts subject to guidelines which emphasize capital preservation and liquidity. The Company is entitled to retain investment income earned on certain of these fiduciary funds in accordance with industry custom and practice and, in some cases, as supported by agreements with insureds. Restricted cash for net uncollected premiums and claims and the related fiduciary liabilities were $14 and $5 at December 31, 2022 and 2021, respectively. Loss and Loss Adjustment Expenses Legacy Financial Guarantee: The loss and loss adjustment expense reserve (“loss reserve”) policy relates only to Ambac’s non-derivative financial guarantee insurance business for insurance policies issued to beneficiaries, including VIEs, for which we do not consolidate the VIE. Losses and loss expenses are based upon estimates of the ultimate aggregate losses inherent in the insured portfolio as of the reporting date. The policy for derivative contracts is discussed in the “Derivative Contracts” section above. A loss reserve is recorded on the balance sheet on a policy-by-policy basis based upon the present value ("PV") of expected net claim cash outflows or expected net recovery cash inflows, discounted at risk-free rates. The estimate for future net cash flows consider the likelihood of all possible outcomes that may occur from missed principal and/or interest payments on the insured obligation. This estimate also considers future recoveries related to breaches of contractual representations and warranties by RMBS transaction sponsors (prior to the settlements as more fully described in Note 1. Background and Business Description ), remediation
Business Combination Disclosure	4. BUSINESS COMBINATION Ambac has acquired the following entities that were accounted for as business combinations and advance Ambac's strategy of expanding into the Insurance Distribution sector. • Effective November 1, 2022, Ambac completed the acquisition of 85% of All Trans and 80% of Capacity Marine for a combined purchase price of $26 in cash. Based on the acquisition date and the complexity of the underlying valuation work, certain amounts included in the Company's Consolidated Financial Statements may be provisional and thus subject to further adjustments within the permitted measurement period as defined by ASC 805. • On December 31, 2020, Ambac completed the acquisition of 80% of the membership interests of Xchange for a purchase price of $81 in cash. All amounts recorded at the time of the acquisitions are final and no subsequent adjustments were made within the permitted measurement period as defined by ASC 805. The following table summarizes the consideration paid for these acquisitions and the estimated fair values of the aggregate assets and liabilities acquired, as well as the fair value of the noncontrolling interest, at the acquisition dates: Fair Value All Trans & Capacity Marine Xchange Cash $ 4 $ 2 Restricted cash 4 4 Intangible assets 16 36 Goodwill 15 46 Other assets 6 8 Total assets acquired $ 45 $ 96 Other liabilities 13 8 Total liabilities assumed 13 8 Less: Redeemable noncontrolling interest 5 7 Total consideration $ 26 $ 81 Goodwill was recorded to reflect the excess purchase consideration over net assets acquired and primarily consists of the future economic benefits that we expect to receive as a result of the acquisitions, driven by the value potential future distribution and carrier relationships, and synergies with other Ambac business operations. Tax deductible goodwill totaled $21 and $65, deductible over 15 years for each of the All Trans and Capacity Marine and Xchange acquisitions, respectively. The fair values assigned to tangible and identifiable intangible assets acquired and liabilities assumed were based on management’s estimates and assumptions at the time of the acquisitions. The fair value of the redeemable non-controlling interest of $5 and $7, respectively on the acquisition dates for the All Trans and Capacity Marine and Xchange acquisitions were estimated based on the non-controlling interest’s respective share of each acquiree's enterprise value, adjusted for the value of Ambac's call options to purchase, and the minority owners' put options to sell to Ambac, respectively, the remaining non-controlling interests. Please refer to the Noncontrolling Interests section of Note 2. Basis of Presentation and Significant Accounting Policies, for further information regarding the terms of the call and put options, as well as the redeemable noncontrolling interest balance sheet classification. The following table sets forth the estimated fair values of identifiable intangible assets acquired and their estimated useful lives as of the date of acquisition. Fair Weighted All Trans & Capacity Marine Distribution relationships $ 15 15.0 Trade name 1 15.0 Total 16 Xchange Distribution relationships $ 33 15.0 Non-compete agreements 1 5.0 Trade name 1 8.0 Total $ 36 The distribution relationships intangible represents existing relationships maintained with a variety of brokers and distributors across its product lines. It excludes the value of potential future distribution relationships that may be developed, which is included in goodwill. The trade name intangible represents the rights to the brand names which are well known in the marketplace that each company competes in. The non-compete agreements intangible relates to agreements entered into with certain key management personnel. The overall weighted average useful life of the identified amortizable intangible assets acquired is 15 years and 14 years for the All Trans and Capacity Marine and Xchange acquisitions, respectively. Pro forma information related to the acquisitions was not presented as the impact was not material to the Company’s financial results.

Segment Reporting

Segment Reporting	12 Months Ended
Segment Reporting	Dec. 31, 2022
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.

Business Combinations

Business Combinations	12 Months Ended
Business Combinations	Dec. 31, 2022
Business Combinations [Abstract]
Business Combination Disclosure	4. BUSINESS COMBINATION Ambac has acquired the following entities that were accounted for as business combinations and advance Ambac's strategy of expanding into the Insurance Distribution sector. • Effective November 1, 2022, Ambac completed the acquisition of 85% of All Trans and 80% of Capacity Marine for a combined purchase price of $26 in cash. Based on the acquisition date and the complexity of the underlying valuation work, certain amounts included in the Company's Consolidated Financial Statements may be provisional and thus subject to further adjustments within the permitted measurement period as defined by ASC 805. • On December 31, 2020, Ambac completed the acquisition of 80% of the membership interests of Xchange for a purchase price of $81 in cash. All amounts recorded at the time of the acquisitions are final and no subsequent adjustments were made within the permitted measurement period as defined by ASC 805. The following table summarizes the consideration paid for these acquisitions and the estimated fair values of the aggregate assets and liabilities acquired, as well as the fair value of the noncontrolling interest, at the acquisition dates: Fair Value All Trans & Capacity Marine Xchange Cash $ 4 $ 2 Restricted cash 4 4 Intangible assets 16 36 Goodwill 15 46 Other assets 6 8 Total assets acquired $ 45 $ 96 Other liabilities 13 8 Total liabilities assumed 13 8 Less: Redeemable noncontrolling interest 5 7 Total consideration $ 26 $ 81 Goodwill was recorded to reflect the excess purchase consideration over net assets acquired and primarily consists of the future economic benefits that we expect to receive as a result of the acquisitions, driven by the value potential future distribution and carrier relationships, and synergies with other Ambac business operations. Tax deductible goodwill totaled $21 and $65, deductible over 15 years for each of the All Trans and Capacity Marine and Xchange acquisitions, respectively. The fair values assigned to tangible and identifiable intangible assets acquired and liabilities assumed were based on management’s estimates and assumptions at the time of the acquisitions. The fair value of the redeemable non-controlling interest of $5 and $7, respectively on the acquisition dates for the All Trans and Capacity Marine and Xchange acquisitions were estimated based on the non-controlling interest’s respective share of each acquiree's enterprise value, adjusted for the value of Ambac's call options to purchase, and the minority owners' put options to sell to Ambac, respectively, the remaining non-controlling interests. Please refer to the Noncontrolling Interests section of Note 2. Basis of Presentation and Significant Accounting Policies, for further information regarding the terms of the call and put options, as well as the redeemable noncontrolling interest balance sheet classification. The following table sets forth the estimated fair values of identifiable intangible assets acquired and their estimated useful lives as of the date of acquisition. Fair Weighted All Trans & Capacity Marine Distribution relationships $ 15 15.0 Trade name 1 15.0 Total 16 Xchange Distribution relationships $ 33 15.0 Non-compete agreements 1 5.0 Trade name 1 8.0 Total $ 36 The distribution relationships intangible represents existing relationships maintained with a variety of brokers and distributors across its product lines. It excludes the value of potential future distribution relationships that may be developed, which is included in goodwill. The trade name intangible represents the rights to the brand names which are well known in the marketplace that each company competes in. The non-compete agreements intangible relates to agreements entered into with certain key management personnel. The overall weighted average useful life of the identified amortizable intangible assets acquired is 15 years and 14 years for the All Trans and Capacity Marine and Xchange acquisitions, respectively. Pro forma information related to the acquisitions was not presented as the impact was not material to the Company’s financial results.

Investments

Investments	12 Months Ended
Investments	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Investments	5. INVESTMENTS Ambac’s non-VIE invested assets are primarily comprised of (i) fixed maturity securities classified as either available-for-sale or trading securities, (ii) interests in pooled investment funds which are reported within Other investments on the Consolidated Balance Sheets and (iii) preferred equity investments 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 and other obligations of Puerto Rico issuing entities that are part of the the PROMESA restructuring process as described further in Note 8. Insurance Contracts. Fixed Maturity Securities The amortized cost and estimated fair value of available-for-sale investments, excluding VIE investments, at December 31, 2022 and 2021 were as follows: Amortized Allowance for Credit Losses Gross Gross Estimated December 31, 2022 Fixed maturity securities: Municipal obligations $ 44 $ — $ — $ 2 $ 43 Corporate obligations 659 — 1 63 598 Foreign obligations 85 — — 9 76 U.S. government obligations 68 — — 4 65 Residential mortgage-backed securities 230 — 28 19 238 Commercial mortgage-backed securities 15 — — — 15 Collateralized debt obligations 141 — — 4 137 Other asset-backed securities (1) 227 — 2 5 224 1,469 — 31 106 1,395 Short-term 507 — — — 507 1,977 — 31 106 1,902 Fixed maturity securities pledged as collateral: Short-term 64 — — — 64 64 — — — 64 Total available-for-sale investments $ 2,041 $ — $ 31 $ 106 $ 1,966 December 31, 2021 Fixed maturity securities: Municipal obligations $ 315 — 28 3 340 Corporate obligations 612 — 10 9 613 Foreign obligations 89 — — 2 87 U.S. government obligations 45 — 1 1 45 Residential mortgage-backed securities 182 — 70 — 252 Collateralized debt obligations 128 — — — 128 Other asset-backed securities (1) 234 — 32 — 265 1,605 — 141 16 1,730 Short-term 415 — — — 414 2,020 — 141 16 2,145 Fixed maturity securities pledged as collateral: U.S. government obligations 15 — — — 15 Short-term 105 — — — 105 120 — — — 120 Total available-for-sale investments 2,140 $ — $ 141 $ 16 $ 2,265 (1) Consists primarily of Ambac's holdings of military housing and student loan securities. The amortized cost and estimated fair value of available-for-sale investments, excluding VIE investments, at December 31, 2022, by contractual maturity, were as follows: Amortized Estimated Due in one year or less $ 606 $ 605 Due after one year through five years 456 427 Due after five years through ten years 317 277 Due after ten years 51 43 1,429 1,353 Residential mortgage-backed securities 230 238 Commercial mortgage-backed securities 15 15 Collateralized debt obligations 141 137 Other asset-backed securities 227 224 Total $ 2,041 $ 1,966 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 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 December 31, 2022 and 2021: Less Than 12 Months 12 Months or More Total Fair Value Gross Fair Value Gross Fair Value Gross December 31, 2022 Fixed maturity securities: Municipal obligations $ 21 $ 1 $ 7 $ 1 $ 28 $ 2 Corporate obligations 280 21 279 42 559 63 Foreign obligations 27 2 47 7 73 9 U.S. government obligations 40 3 19 1 58 4 Residential mortgage-backed securities 132 19 — — 132 19 Commercial mortgage-backed securities 3 — — — 3 — Collateralized debt obligations 90 3 36 1 126 4 Other asset-backed securities 198 4 5 1 203 5 791 53 392 53 1,183 106 Short-term 78 — 8 — 86 — Total temporarily impaired securities $ 869 $ 53 $ 400 $ 53 $ 1,269 $ 106 Less Than 12 Months 12 Months or More Total Fair Value Gross Fair Value Gross Fair Value Gross December 31, 2021 Fixed maturity securities: Municipal obligations $ 117 $ 3 $ 2 $ — $ 118 $ 3 Corporate obligations 363 8 17 1 380 9 Foreign obligations 75 2 3 — 78 2 U.S. government obligations 25 — 2 — 27 1 Residential mortgage-backed securities — — 1 — 2 — Collateralized debt obligations 68 — 3 — 71 — Other asset-backed securities 6 — — — 6 — 654 14 28 1 682 16 Short-term 114 — 13 — 128 — 768 14 41 1 810 16 Fixed income securities, pledged as collateral: U.S. government obligations 15 — — — 15 — Total collateralized investments 15 — — — 15 — Total temporarily impaired securities $ 783 $ 14 $ 41 $ 1 $ 825 $ 16 Management has determined that the securities in the above table do not have credit impairment as of December 31, 2022 and 2021 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 December 31, 2022, 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 December 31, 2022 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 December 31, 2022 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 584 investment grade securities with an average unrealized loss equal to 10% of amortized cost at December 31, 2022. Securities that have below investment grade credit ratings or are unrated comprise $2 of the gross unrealized loss and have an average unrealized loss equal to 8% of amortized cost at December 31, 2022. Management believes that the full and timely receipt of all principal and interest payment on corporate obligations with unrealized losses as of December 31, 2022 is probable. Residential mortgage-backed securities and Other asset-backed securities As of December 31, 2022, all of the $19 unrealized loss on residential mortgage-backed securities related to 13 Ambac-insured securities. Five of these account for $18 of the unrealized loss and have an average unrealized loss equal to 15% of amortized cost. The $5 unrealized loss on other asset backed securities related to 14 Ambac-insured securities or resecuritization instruments collateralized with Ambac-insured securities and have an average unrealized loss equal to 2% 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 on Ambac-insured securities. 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: Year Ended December 31, 2022 2021 2020 Fixed maturity securities $ 61 $ 78 $ 103 Short-term investments 11 — 5 Loans 1 — 1 Investment expense (6) (6) (6) Securities available-for-sale and short-term 66 74 103 Fixed maturity securities - trading (23) — — Other investments (26) 66 19 Total net investment income (loss) $ 17 $ 139 $ 122 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: Year Ended December 31, 2022 2021 2020 Gross realized gains on securities $ 36 $ 14 $ 38 Gross realized losses on securities (18) (2) (12) Foreign exchange (losses) gains 14 (5) (4) Credit impairments — — — Intent / requirement to sell impairments — — — Net investment gains (losses), including impairments $ 31 $ 7 $ 22 Ambac had an allowance for credit losses $— and $— at December 31, 2022 and 2021, respectively. Ambac did not purchase any financial assets with credit deterioration for the years ended December 31, 2022 and 2021. 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 $64 and $120 at December 31, 2022 and 2021, 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 “Fixed maturity securities pledged as collateral, at fair value” and "Short-term investments pledged as collateral, at fair value". Refer to Note 10. 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 $23 and $17 at December 31, 2022 and 2021, 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 as December 31, 2022, were deposited as security in connection with a letter of credit issued for an office lease. Securities with a fair value of $669 at December 31, 2021, were held by Ambac UK, the capital stock of which was pledged as collateral for the Sitka AAC Note. The Sitka AAC Note was fully redeemed as of October 29, 2022, and therefore the pledge of Ambac UK's capital stock was subsequently released. Refer to Note 13. Long-term Debt for further information about the Sitka AAC Note. Guaranteed Securities Ambac’s fixed maturity portfolio includes securities covered by guarantees issued by AAC and other financial guarantors (“insured securities”). The published rating agency ratings on these securities reflect the higher of the financial strength rating of the financial guarantor or the rating of the underlying issuer. Rating agencies do not always publish separate underlying ratings (those ratings excluding the insurance by the financial guarantor). In the event these underlying ratings are not available from the rating agencies, Ambac will assign an internal rating. The following table represents the fair value and weighted-average underlying rating of insured securities in Ambac's investment portfolio at December 31, 2022 and 2021, respectively: Municipal Corporate Mortgage Total Weighted (1) December 31, 2022: Ambac Assurance Corporation $ 10 $ — $ 394 $ 403 B Total $ 10 $ — $ 394 $ 403 B December 31, 2021: Ambac Assurance Corporation $ 316 $ — $ 439 $ 754 B National Public Finance Guarantee Corporation 2 — — 2 BBB- Assured Guaranty Municipal Corporation 1 — — 1 A- Total $ 318 $ — $ 439 $ 757 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 $53 to private credit and private equity funds at December 31, 2022. Class of Funds December 31, 2022 2021 Redemption Frequency Redemption Notice Period Hedge funds (1) $ 186 $ 216 quarterly or semi-annually 90 days Private credit (4) 84 88 quarterly if permitted 180 days if permitted High yield and leveraged loans (5) 80 78 daily 0 - 30 days Equity market investments (3) (11) 64 98 daily or quarterly 0 - 90 days Investment grade floating rate income (2) 63 107 weekly 0 days Private equity (6) 47 37 quarterly if permitted 90 days if permitted Real estate properties (7) 22 33 quarterly 10 business days Convertible bonds (10)(11) 8 — daily 0 days Emerging markets debt (8) (11) — 24 daily 0 days Insurance-linked investments (9) 1 2 see footnote (9) see footnote (9) Total equity investments in pooled funds $ 556 $ 683 (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 of funds includes investments in high quality floating rate debt securities including ABS and corporate floating rate notes. (3) This class of funds aim to achieve long-term growth through diversified exposure to global equity markets. (4) This class aims to obtain high long-term returns primarily through credit and preferred equity investments with low liquidity and defined term. (5) 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. (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 (8) This class seeks long-term income and growth through investments in the bonds of issuers in emerging markets. (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) This class seeks to generate total return from portfolios focused primarily on convertible securities (11) These categories include fair value amounts totaling $61 and $106 at December 31, 2022 and 2021, respectively, that are readily determinable and are priced through pricing vendors, for Equity market investments of $53 and $82; Convertible bonds investments $8 and $—; and for Emerging markets debt of $— and $24. Other investments also includes preferred equity investments with a carrying value of $12 and $8 as of December 31, 2022 and 2021, respectively, that do not have readily determinable fair values and are carried at cost, less any impairments as permitted under the Investments — Equity Securities Topic of the ASC. There were no impairments recorded on these investments or adjustments to fair value to reflect observable price changes in identical or similar investments from the same issuer during the periods presented. The portion of net unrealized gains (losses) related to securities classified as trading and equity securities, excluding those reported using the equity method, still held at the end of each period is as follows: Year Ended December 31, 2022 2021 2020 Net gains (losses) recognized during the period on trading securities $ (48) $ 23 $ — Less: net gains (losses) recognized during the reporting period on trading securities sold during the period (26) 1 (18) Unrealized gains (losses) recognized during the reporting period on trading securities still held at the reporting date $ (22) $ 22 $ 18
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 December 31, 2022 and 2021, respectively: Municipal Corporate Mortgage Total Weighted (1) December 31, 2022: Ambac Assurance Corporation $ 10 $ — $ 394 $ 403 B Total $ 10 $ — $ 394 $ 403 B December 31, 2021: Ambac Assurance Corporation $ 316 $ — $ 439 $ 754 B National Public Finance Guarantee Corporation 2 — — 2 BBB- Assured Guaranty Municipal Corporation 1 — — 1 A- Total $ 318 $ — $ 439 $ 757 B (1) Ratings are based on the lower of Standard & Poor’s or Moody’s rating. If unavailable, Ambac’s internal rating is used.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
Fair Value Measurements	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	6. 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 December 31, 2022 and 2021, 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. Carrying Total Fair Fair Value Measurements Categorized as: Level 1 Level 2 Level 3 December 31, 2022: Financial assets: Fixed maturity securities: Municipal obligations $ 102 $ 102 $ — $ 102 $ — Corporate obligations 598 598 — 585 12 Foreign obligations 76 76 76 — — U.S. government obligations 65 65 65 — — Residential mortgage-backed securities 238 238 — 238 — Commercial mortgage-backed securities 15 15 — 15 — Collateralized debt obligations 137 137 — 137 — Other asset-backed securities 224 224 — 157 67 Fixed maturity securities, pledged as collateral: Short-term 64 64 64 — — Short term investments 507 507 506 1 — Other investments (1) 568 556 61 — — Cash, cash equivalents and restricted cash 44 44 43 1 — Derivative assets: Interest rate swaps—asset position 27 27 — 1 26 Warrants 1 1 — — 1 Other assets-loans 10 10 — — 10 Variable interest entity assets: Fixed maturity securities: Corporate obligations, fair value option 1,828 1,828 — — 1,828 Fixed maturity securities: Municipal obligation, trading 43 43 — 43 — Fixed maturity securities: Municipal obligations, available-for-sale 96 96 — 96 — Restricted cash 17 17 17 — — Loans 1,829 1,829 — — 1,829 Derivative assets: Interest rate swaps—asset position 190 190 — 190 — Derivative assets: Currency swaps—asset position 49 49 — 49 — Total financial assets $ 6,537 $ 6,525 $ 833 $ 1,425 $ 3,772 Financial liabilities: Long term debt, including accrued interest $ 1,065 $ 878 $ — $ 864 $ 14 Derivative liabilities: Interest rate swaps—liability position 38 38 — 38 — Liabilities for net financial guarantees written (2) 159 476 — — 476 Variable interest entity liabilities: Long-term debt (includes $2,788 at fair value) 3,107 3,145 — 2,992 154 Derivative liabilities: Interest rate swaps—liability position 1,048 1,048 — 1,048 — Total financial liabilities $ 5,418 $ 5,586 $ — $ 4,942 $ 644 Carrying Total Fair Fair Value Measurements Categorized as: Level 1 Level 2 Level 3 December 31, 2021: Financial assets: Fixed maturity securities: Municipal obligations $ 340 $ 340 $ — $ 340 $ — Corporate obligations 613 613 1 600 12 Foreign obligations 87 87 87 — — U.S. government obligations 45 45 45 — — Residential mortgage-backed securities 252 252 — 252 — Collateralized debt obligations 128 128 — 128 — Other asset-backed securities 265 265 — 187 79 Fixed maturity securities, pledged as collateral: U.S. government obligations 15 15 15 — — Short-term 105 105 105 — — Short term investments 414 414 369 46 — Other investments (1) 690 683 106 — — Cash, cash equivalents and restricted cash 21 21 21 1 — Derivative assets: Interest rate swaps—asset position 76 76 — 5 71 Other assets-loans 3 3 — — 3 Variable interest entity assets: Fixed maturity securities: Corporate obligations, fair value option 3,320 3,320 — — 3,320 Fixed maturity securities: Municipal obligations, available-for-sale 136 136 — 136 — Restricted cash 2 2 2 — — Loans 2,718 2,718 — — 2,718 Derivative assets; Currency swaps-asset position 38 38 — 38 — Total financial assets $ 9,268 $ 9,261 $ 750 $ 1,732 $ 6,202 Financial liabilities: Long term debt, including accrued interest $ 2,806 $ 2,598 $ — $ 2,575 $ 22 Derivative liabilities: Interest rate swaps—liability position 94 94 — 94 — Liabilities for net financial guarantees written (2) (866) (112) — — (112) Variable interest entity liabilities: Long-term debt (includes $4,056 at fair value) 4,216 4,255 — 4,086 169 Derivative liabilities: Interest rate swaps—liability position 1,940 1,940 — 1,940 — Total financial liabilities $ 8,190 $ 8,775 — 8,695 79 (1) Excluded from the fair value measurement categories in the table above are investment funds of $494 and $577 as of December 31, 2022 and 2021, respectively, which are measured using NAV as a practical expedient. Also excluded from the fair value measurements in the table above are equity securities with a carrying value of $12 and $8 as of December 31, 2022 and 2021, 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 adjustment 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 many of the financial instruments valued using significant unobservable inputs 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 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. At December 31, 2021, approximately 6%, 90%, 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 $67 and $79 at December 31, 2022 and 2021, 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 December 31, 2022 and 2021 include the following: December 31, 2022: a. Coupon rate 5.98% b. Average Life 13.46 years c. Yield 12.60% December 31, 2021: a. Coupon rate 5.97% b. Average Life 14.14 years c. Yield 10.20% Corporate obligations: This includes certain investments in convertible debt securities. The fair value classified as Level 3 was $12 and $12 at December 31, 2022 and 2021, respectively. Fair value was calculated by discounting cash flows to average maturity of 1.75 years and yield of 11.3% at December 31, 2022, and 2.75 years and a yield of 11.6% at December 31, 2021. 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 5. 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 also 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 both December 31, 2022 or 2021. 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. All of Ambac's credit derivatives ("CDS") positions have terminated as of June 30, 2022 and were not significant to Ambac's financial position or results of operations for the periods presented. As of December 31, 2022 Ambac holds warrants to purchase preferred stock of a development stage company. These warrants have a fair value of $1 as of December 31, 2022, 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 As of December 31, 2022, long-term debt includes AAC surplus notes, Tier 2 Notes issued in connection with the conclusion of the rehabilitation of the Segregated Account of AAC, and the Ambac UK debt issued in connection with the Ballantyne commutation. As described in Note 1. Background and Business Description , the Sitka AAC Note was wholly redeemed effective October 29, 2022, and Tier 2 Notes were partially redeemed effective October 29, 2022 and fully redeemed effective January 15, 2023. The fair values of surplus notes, Sitka AAC Note 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 12. 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 6.8% and 3.0% at December 31, 2022 and 2021, respectively. At December 31, 2022, the range of these discount rates was between 5.8% and 8.5%. At December 31, 2021, the range of these discount rates was between 2.2% and 4.1%. 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 2022, 2021 and 2020. 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 and Liabilities Year ended December 31, 2022 Investments (1) Other Derivatives Investments Loans Total Balance, beginning of period $ 91 $ — $ 70 $ 3,320 $ 2,718 $ 6,199 Total gains/(losses) realized and unrealized: Included in earnings 1 — (38) (789) (333) (1,160) Included in other comprehensive income (12) — — (353) (279) (644) Purchases — — — — — — Issuances — — — — — — Sales — — — — — — Settlements (1) — (6) (349) (278) (633) Balance, end of period $ 79 $ — $ 26 $ 1,828 $ 1,829 $ 3,762 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 $ — $ (38) $ (789) $ (333) $ (1,160) 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 $ (12) $ — $ — $ (353) $ (279) $ (644) Level-3 Financial Assets and Liabilities Accounted for at Fair Value VIE Assets and Liabilities Year Ended December 31, 2021 Investments (1) Other Assets (2) Derivatives Investments Loans Total Balance, beginning of period $ 78 $ 1 $ 84 $ 3,215 $ 2,998 $ 6,376 Total gains/(losses) realized and unrealized: Included in earnings 1 — (6) 176 59 230 Included in other comprehensive income 1 — — (32) (26) (58) Purchases 13 — — — — 13 Issuances — — — — — — Sales — — — — — — Settlements (2) (1) (8) (38) (313) (362) Balance, end of period $ 91 $ — $ 70 $ 3,320 $ 2,718 $ 6,199 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) $ — $ (6) $ 176 $ 59 $ 227 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 $ (1) $ — $ — $ (32) $ (26) $ (59) Level-3 Financial Assets and Liabilities Accounted for at Fair Value VIE Assets and Liabilities Year Ended December 31, 2020 Investments (1) Other Assets (2) Derivatives Investments Loans Total Balance, beginning of period $ 72 $ 3 $ 66 $ 2,957 $ 3,108 $ 6,207 Total gains/(losses) realized and unrealized: Included in earnings 1 (2) 25 183 98 306 Included in other comprehensive income 6 — — 109 83 198 Purchases — — — — — — Issuances — — — — — — Sales — — — — — — Settlements (1) — (7) (35) (290) (334) Balance, end of period $ 78 $ 1 $ 84 $ 3,215 $ 2,998 $ 6,376 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 $ (2) $ 25 $ 183 $ 98 $ 305 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 $ 6 $ — $ — $ 109 $ 83 $ 198 (1) Investments classified as Level 3 consist of a one other asset-backed security and two convertible notes acquired in 2021. (2) Other assets carried at fair value and classified as Level 3 relate to an equity interest in an Ambac sponsored VIE liquidated in 2021. 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: Net Investment Income Net Gains Income (Loss) on Variable Interest Entities Other Year Ended December 31, 2022 Total gains (losses) included in earnings for the period $ 1 $ (38) $ (1,123) $ — Changes in unrealized gains (losses) relating to financial instruments still held at the reporting date 1 (39) (1,123) — Year Ended December 31, 2021 Total gains (losses) included in earnings for the period $ 1 $ (6) $ 235 $ — Changes in unrealized gains (losses) relating to financial instruments still held at the reporting date 1 (6) 235 — Year Ended December 31, 2020 Total gains (losses) included in earnings for the period $ 1 $ 25 $ 281 $ (2) Changes in unrealized gains (losses) relating to financial instruments still held at the reporting date — 25 281 (2)

Financial Guarantees in Force (

Financial Guarantees in Force (Notes)	12 Months Ended
Financial Guarantees in Force (Notes)	Dec. 31, 2022
Guarantees [Abstract]
Financial Guarantees in Force	7. FINANCIAL GUARANTEES IN FORCE Legacy financial guarantees outstanding includes the exposures of policies that insure variable interest entities (“VIEs”) consolidated in accordance with ASC Topic 810, Consolidation. Financial guarantees outstanding include the exposure of policies that insure 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 bonds. Financial guarantees outstanding exclude the exposures of policies that insure bonds which have been called, pre-refunded or refunded and excludes exposure of the policies insuring the Sitka Senior Secured Notes as defined in Note 1. Background and Business Description. The gross par amount of financial guarantees outstanding was $27,551 and $34,122 at December 31, 2022 and 2021, respectively. The par amount of financial guarantees outstanding, net of reinsurance, was $22,613 and $28,020 at December 31, 2022 and 2021, respectively. As of December 31, 2022, the aggregate amount of financial guarantee insured par ceded to reinsurers under reinsurance agreements was $4,938 with the largest reinsurer accounting for $2,187 or 7.9% of gross par outstanding at December 31, 2022. As of December 31, 2022 and 2021, the legacy financial guarantee portfolio consisted of the types of guaranteed bonds as shown in the following table: Net Par Outstanding December 31, (1) 2022 2021 Public Finance: Housing revenue (2) $ 5,491 $ 5,610 Lease and tax-backed revenue 1,979 3,196 General obligation 1,301 1,612 Other 1,776 1,942 Total Public Finance 10,547 12,360 Structured Finance: Mortgage-backed and home equity 1,930 2,724 Investor-owned utilities 1,103 1,556 Other 579 624 Total Structured Finance 3,612 4,904 International Finance: Sovereign/sub-sovereign 4,077 5,141 Investor-owned and public utilities 2,583 3,283 Asset-backed and other 1,083 1,276 Transportation 711 1,056 Total International Finance 8,454 10,756 Total $ 22,613 $ 28,020 (1) Net Par Outstanding includes 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. (2) Includes $5,400 and $5,490 of Military Housing net par at December 31, 2022 and 2021, respectively. As of December 31, 2022 and 2021, the financial guaranteed portfolio by location of risk was as outlined in the table below: Net Par Outstanding December 31, 2022 2021 United States $ 14,159 $ 17,264 United Kingdom 7,223 9,255 Italy 644 718 Austria 310 343 Australia 259 203 France 14 219 Other international 4 18 Total $ 22,613 $ 28,020 Gross financial guarantees in force (principal and interest) were $44,734 and $54,272 at December 31, 2022 and 2021, respectively. Net financial guarantees in force (after giving effect to reinsurance) were $34,975 and $42,653 as of December 31, 2022 and 2021, respectively.

Financial Guarantee Insurance C

Financial Guarantee Insurance Contracts	12 Months Ended
Financial Guarantee Insurance Contracts	Dec. 31, 2022
Insurance [Abstract]
Reinsurance	Reinsurance Recoverables, Including Credit Impairments: The Company uses ceded reinsurance to transfer certain insurance risk, along with premiums written and earned, to other insurance carriers that agree to share in such risks. The primary purpose of the reinsurance is to (i) protect the Company, at a cost, from losses in excess of amounts it is willing to accept, (ii) protect the Company's capital, and (iii) within the Specialty Property and Casualty Insurance operations, to manage the Company's net retention on individual risks and overall exposure to losses while providing the Company the ability to offer policies with sufficient limits to meet policyholder needs. • Within its Specialty Property and Casualty Insurance segment, the Company generally enters into quota share reinsurance agreements whereby the Company cedes to the capacity providers (reinsurers) a substantial amount (generally 70% or more) of its gross liability under all policies issued by and on behalf of the Company by the MGA/U. Ambac is exposed to the credit risk of the reinsurer, or the risk that one of its reinsurers becomes insolvent or otherwise unable or unwilling to pay policyholder claims. This credit risk is generally mitigated by either selecting well capitalized, highly rated authorized capacity providers or requiring that the capacity provider post collateral to secure the reinsured risks, which in some instances, exceeds the related reinsurance recoverable. Amounts recoverable from reinsurers are estimated in a manner consistent with the associated loss and loss adjustment expense reserves. The Company reports its reinsurance recoverables net of an allowance for amounts that are estimated to be uncollectible. Ambac’s reinsurance assets, including deferred ceded premiums and reinsurance recoverables on losses amounted to $239 at December 31, 2022. Credit exposure existed at December 31, 2022, with respect to reinsurance recoverables to the extent that any reinsurer may not be able to reimburse Ambac under the terms of these reinsurance arrangements. At December 31, 2022, there were ceded reinsurance balances payable of $39 offsetting this credit exposure. Contractually ceded reinsurance payables can only be offset against amounts owed from the same reinsurer in the event that such reinsurer is unable to meet its obligations to reimburse Ambac. To minimize its credit exposure to losses from reinsurer insolvencies, Ambac (i) is entitled to receive collateral from its reinsurance counterparties in certain reinsurance contracts and (ii) has certain cancellation rights that can be exercised by Ambac in the event of rating agency downgrades of a reinsurer (among other events and circumstances). Ambac held letters of credit and collateral amounting to $116 from its reinsurers at December 31, 2022. For those reinsurance counterparties that do not currently post collateral, Ambac's reinsurers are well capitalized, highly rated, authorized capacity providers. Additionally, while legacy liabilities from the PWIC acquisition and the three admitted carriers acquired by Everspan on January 3, 2022(the "21st Century Companies") were fully ceded to certain reinsurers, Everspan also benefits from an unlimited, uncapped indemnity from Enstar Holdings (US) and 21st Century Premier Insurance Company, respectively, to mitigate any residual risk to these reinsurers. The allowance for credit losses is based upon Ambac's ongoing review of amounts outstanding and the key indicators management uses to assess the credit quality of reinsurance recoverables are collateral posted by the reinsurers and independent rating agency credit ratings. The evaluation begins with a comparison of the fair value of collateral posted by the reinsurer to the recoverable, net of ceded premiums payable. Any shortfall of collateral posted is evaluated against the credit rating of the reinsurer to determine whether an allowance is considered necessary. For 2022, our top three reinsurers represented 84.2% of our total ceded reinsurance recoverables, and reinsurance recoverables were primarily from reinsurers with applicable ratings of A or better. The following table sets forth our three most significant reinsurers by amount of reinsurance recoverable as of December 31, 2022. Reinsurers Type of Insurance Rating (1) Reinsurance Recoverable (2) Unsecured Recoverable (3) QBE Insurance Corporation Specialty P&C A $ 41 $ 41 Assured Guaranty Re Ltd. Financial AA 30 — General Reinsurance Company Specialty P&C A++ 25 11 All other reinsurers 18 7 Total recoverables $ 115 $ 60 (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. The allowance for credit losses is based upon Ambac's ongoing review of amounts outstanding. Key indicators management uses to assess the credit quality of reinsurance recoverables are financial performance of the reinsurers, collateral posted by the reinsurers and independent rating agency credit ratings. The evaluation begins with a comparison of the fair value of collateral posted by the reinsurer to the recoverable, net of ceded premiums payable. Any shortfall of collateral posted is evaluated against our assessment of the reinsurer's financial strength, including its credit rating to determine whether an allowance is considered necessary. Ambac has uncollateralized credit exposure of $60 and $32 and has recorded an allowance for credit losses of less than a million at December 31, 2022 and December 31, 2021, respectively. The uncollateralized credit exposure includes legacy liabilities obtained from the acquisitions of PWIC and the 21st Century Companies of $45 and $30 at December 31, 2022 and December 31, 2021, respectively. Legacy liabilities are also supported by an unlimited, uncapped indemnity from Enstar Holdings (US) and 21st Century Premier Insurance Company, respectively.
Puerto Rico Disclosure	8. INSURANCE CONTRACTS Amounts presented in this Note relate only to Ambac’s non-derivative insurance business for insurance policies issued to beneficiaries, excluding consolidated VIEs. Premiums The effect of reinsurance on premiums written and earned was as follows: Year Ended Direct Assumed Ceded Net 2022: Written $ 127 $ — $ 104 $ 23 Earned 126 — 69 56 2021: Written $ 2 $ — $ 35 $ (33) Earned 62 — 15 47 2020: Written $ (1) $ — $ (1) $ — Earned 65 1 12 54 Included in net earned premiums are accelerated financial guarantee premium revenues for retired obligations for the years ended December 31, 2022, 2021 and 2020, of $8, $1 and $12, respectively. The following table summarizes net premiums earned by location of risk: Year Ended December 31, 2022 2021 2020 United States 41 $ 27 $ 32 United Kingdom 13 14 24 Other international 3 6 (2) Total 56 $ 47 $ 54 Premium Receivables, including credit impairments Premium receivables at December 31, 2022 and 2021 were $269 and $323, respectively. Management evaluates premium receivables for expected credit losses ("credit impairment") in accordance with the CECL standard adopted January 1, 2020, which is further described in Note 2. Basis of Presentation and Significant Accounting Policies . The key indicator management uses to assess the credit quality of legacy financial guarantee premium receivables is Ambac's internal risk classifications for the insured obligation determined by the Risk Management Group. Below is the amortized cost basis of financial guarantee premium receivables by risk classification code and asset class as of December 31, 2022 and 2021: Surveillance Categories as of December 31, 2022 Type of Guaranteed Bond I IA II III IV Total Public Finance: Housing revenue $ 140 $ 3 $ 5 $ — $ — $ 148 Other 2 — — — — 2 Total Public Finance 142 3 5 — — 150 Structured Finance: Mortgage-backed and home equity — — — — 11 11 Student loan 1 1 — 7 — 8 Structured insurance — — — — — — Other 4 — — — — 4 Total Structured Finance 5 1 — 7 11 24 International: Sovereign/sub-sovereign 49 7 — 9 — 64 Investor-owned and public utilities 18 — — — — 18 Other 2 — — — — 2 Total International 70 7 — 9 — 85 Total (1) (2) $ 217 $ 10 $ 5 $ 16 $ 11 $ 259 Surveillance Categories as of December 31, 2021 Type of Guaranteed Bond I IA II III IV Total Public Finance: Housing revenue $ 149 $ 3 $ 5 $ — $ — $ 157 Other 2 — — — — 2 Total Public Finance 151 3 5 — — 159 Structured Finance: Mortgage-backed and home equity 1 — 1 2 12 16 Student loan 1 1 — 9 — 12 Structured insurance 10 — — — — 10 Other 7 — — — — 7 Total Structured Finance 19 1 1 12 12 45 International: Sovereign/sub-sovereign 74 8 — 11 — 93 Investor-owned and public utilities 28 — — — — 28 Other 5 — — — — 5 Total International 107 8 — 11 — 125 Total (2) $ 277 $ 12 $ 6 $ 22 $ 12 $ 329 (1) Excludes specialty property and casualty premium receivables of $16 and $2 at December 31, 2022 and 2021, respectively. (2) The underwriting origination dates for all policies included are greater than five years prior to the current reporting date. Below is a rollforward of the premium receivable allowance for credit losses as of December 31, 2022 and 2021: Year Ended December 31, 2022 2021 Beginning balance $ 9 $ 17 Current period provision (benefit) (4) (6) Write-offs of the allowance — (2) Recoveries of previously written-off amounts — — Ending balance $ 5 $ 9 At December 31, 2022 and 2021, $— and $— of premiums were past due. Legacy Financial Guarantee Premium Receivables Gross premiums are received either upfront or in installments. For premiums received upfront, an unearned premium revenue (“UPR”) liability is established, which is initially recorded as the cash amount received. For installment premium policies, a premium receivable asset and offsetting UPR liability is initially established in an amount equal to: (i) the present value of future contractual premiums due (the “contractual” method) or (ii) if the assets underlying the insured obligation are homogenous pools which are contractually prepayable, the present value of premiums to be collected over the expected life of the transaction (the “expected” method). Below is the gross premium receivable roll-forward (direct contracts), net of the allowance for credit losses, for the affected periods: Year Ended 2022 2021 2020 Beginning premium receivable $ 320 $ 370 $ 416 Adjustment to initially apply ASU 2016-13 — — (3) Premium receipts (36) (35) (46) Adjustments for changes in expected and contractual cash flows for contracts (1) (31) (27) (6) Accretion of premium receivable discount for contracts 8 8 9 Changes to allowance for credit losses 4 8 (4) Other adjustments (including foreign exchange) (2) (12) (4) 5 Ending premium $ 254 $ 320 $ 370 (1) Adjustments for changes in expected and contractual cash flows are primarily due to higher discount rates and reductions in insured exposure as a result of early policy terminations and unscheduled principal paydowns . (2) Includes foreign exchange gains/(losses) of ($13), ($2) and $4 for 2022, 2021,and 2020 respectively. (3) Premium receivable includes premiums to be received in foreign denominated currencies most notably in British Pounds and Euros. At December 31, 2022, 2021 and 2020 premium receivables include British Pounds of $71 (£59), $108 (£80) and $117 (£86), respectively, and Euros of $14 (€13), $16 (€14) and $19 (€16), respectively. The following table summarizes the future gross undiscounted premiums to be collected and future premiums earned, net of reinsurance at December 31, 2022: Future Premiums Collected (1) Future to be Earned Net of (2) Three months ended: March 31, 2023 $ 8 $ 5 June 30, 2023 7 5 September 30, 2023 7 5 December 31, 2023 5 5 Twelve months ended: December 31, 2024 26 19 December 31, 2025 25 18 December 31, 2026 24 18 December 31, 2027 23 17 Five years ended: December 31, 2032 95 70 December 31, 2037 59 42 December 31, 2042 27 17 December 31, 2047 13 8 December 31, 2052 4 2 December 31, 2057 — — Total $ 322 $ 231 (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 . 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. Loss and Loss Adjustment Expense Reserves Ambac's loss and loss adjustment 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 adjustment expense reserves and the subrogation recoverable asset at December 31, 2022 and 2021: Legacy Financial Guarantee Specialty Property and Casualty Present Value of Expected Balance Sheet Line Item Gross Loss and Claims and Recoveries Unearned Gross Loss and December 31, 2022: Loss and loss adjustment expense reserves $ 90 $ 787 $ (44) $ (28) $ 805 Subrogation recoverable — 5 (276) — (271) Totals $ 90 $ 791 $ (319) $ (28) $ 534 December 31, 2021: Loss and loss adjustment expense reserves $ 32 $ 1,749 $ (155) $ (56) $ 1,570 Subrogation recoverable — 88 (2,180) — (2,092) Totals $ 32 $ 1,837 $ (2,335) $ (56) $ (522) Below is the loss and loss reserve expense roll-forward, net of subrogation recoverable and reinsurance, for the affected periods. Year Ended December 31, 2022 2021 2020 Beginning gross loss and loss adjustment expense reserves $ (522) $ (397) $ (482) Reinsurance recoverable 55 33 26 Beginning balance of net loss and loss adjustment expense reserves (578) (430) (508) Losses and loss expenses (benefit) incurred: Current year 4 — 15 Prior years (401) (89) 210 Total (1)(2) (397) (88) 225 Loss and loss adjustment expenses (recovered) paid: Current year 7 — 1 Prior years (1,867) 59 148 Total (1,860) 59 149 Foreign exchange effect (2) — 2 Ending net loss and loss adjustment expense reserves 883 (578) (430) Impact of VIE consolidation (3) (464) — — Reinsurance recoverable (4) 115 55 33 Ending gross loss and loss adjustment expense reserves 534 (522) (397) (1) Total losses and loss expenses (benefit) includes $(41), $5 and $(7) for the years ended December 31, 2022, 2021 and 2020, respectively, related to ceded reinsurance. (2) Ambac records the impact of estimated recoveries related to securitized loans in RMBS transactions that breached certain representations and warranties ("R&W's") by transaction sponsors within losses and loss expenses (benefit) for the Legacy Financial Guarantee segment. The losses and loss expense (benefit) incurred associated with changes in estimated R&W's for the year ended December 31, 2022, 2021 and 2020 was $(123), $20 and $(23), respectively. Refer to Note 1. Background and Business Description to the Consolidated Financial Statements in this Annual Report on Form 10-K for details of the RMBS litigation settlements reached in October and December 2022. (3) In connection with the Puerto Rico restructuring, three new trusts were established for the year ended December 31, 2022. These trusts were consolidated by Ambac as further discussed in Note 12. Variable Interest Entities. (4) Represents reinsurance recoverable on future loss and loss adjustment expenses. Additionally, the Balance Sheet line "Reinsurance recoverable on paid and unpaid losses" includes reinsurance recoverables (payables) of $0, $0 and $0 as of December 31, 2022, 2021 and 2020, respectively, related to previously presented loss and loss adjustment expenses and subrogation. For 2022, the positive development in prior years was primarily attributable to the Puerto Rico restructuring and favorable RMBS development due to the positive impact of discount rates and the impact of the litigation settlements with Bank of America Corporation and certain affiliates thereof and Nomura Credit & Capital, Inc. as described in Note 1. Background and Business Description to the Consolidated Financial Statements in this Annual Report on Form 10-K; both in the legacy financial guarantee segment. For 2022, prior years' loss and loss expenses recovered includes $1,687 related the litigation settlement with Bank of America Corporation and certain affiliates. For 2021, the positive development in prior years was primarily due to favorable development in Public Finance credits (largely Puerto Rico) and the RMBS portfolio. For 2020, the adverse development in prior years was primarily a result of deterioration in Public Finance credits, largely Puerto Rico, partially offset by favorable development in the RMBS portfolio. Legacy Financial Guarantee Loss Reserves: The tables below summarize information related to policies currently included in Ambac’s loss and loss adjustment expense reserves or subrogation recoverable at December 31, 2022 and 2021, 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 December 31, 2022 and 2021 was 3.9% and 1.2%, respectively. 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 13 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 adjustment expense reserves $ (10) $ (2) $ 32 $ 252 $ 137 $ 34 $ 444 Reinsurance recoverable reported on $ 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 adjustment expenses and $0 related to presented loss and loss adjustment expenses and subrogation. Surveillance Categories as of December 31, 2021 I IA II III IV V Total Number of policies 34 15 7 14 130 5 205 Remaining weighted-average contract period (in years) (1) 9 12 14 15 13 7 14 Gross insured contractual payments outstanding: Principal $ 904 $ 840 $ 459 $ 1,300 $ 2,759 $ 40 $ 6,302 Interest 589 612 308 169 1,284 22 2,984 Total $ 1,493 $ 1,452 $ 767 $ 1,469 $ 4,043 $ 62 $ 9,286 Gross undiscounted claim liability $ 5 $ 16 $ 45 $ 544 $ 1,423 $ 62 $ 2,095 Discount, gross claim liability — (1) (3) (109) (185) (4) (303) Gross claim liability before all subrogation and before reinsurance $ 5 $ 15 $ 42 $ 435 $ 1,238 $ 57 $ 1,792 Less: Gross RMBS subrogation (2) $ — $ — $ — $ — $ (1,737) $ — $ (1,737) Discount, RMBS subrogation — — — — 7 — 7 Discounted RMBS subrogation, before reinsurance — — — — (1,730) — (1,730) Less: Gross other subrogation (3) — (5) — (33) (583) (12) (633) Discount, other subrogation — — — 2 24 2 28 Discounted other subrogation, before reinsurance — (5) — (31) (559) (10) (605) Gross claim liability, net of all subrogation and discounts, before reinsurance $ 5 $ 10 $ 42 $ 404 $ (1,051) $ 47 $ (543) Less: Unearned premium revenue $ (3) $ (10) $ (5) $ (14) $ (24) $ (1) $ (56) Plus: Loss expense reserves 1 — — 4 40 — 45 Gross loss and loss adjustment expense reserves $ 3 $ 1 $ 38 $ 394 $ (1,036) $ 46 $ (554) Reinsurance recoverable reported on $ 1 $ 1 $ 10 $ 22 $ (11) $ — $ 23 (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 $24 related to future loss and loss adjustment expenses and $0 related to presented loss and loss adjustment expenses and subrogation. Puerto Rico Ambac has remaining exposure to the Commonwealth of Puerto Rico (the "Commonwealth") and its instrumentalities on two different issuing entities with total net par exposure of $244. Components of the remaining Puerto Rico net par outstanding include capital appreciation bonds which are reported at the par amount at the time of issuance of the related insurance policy as opposed to the current accreted value of the bonds. We have been paying claims for several years on most of our exposure to Puerto Rico, which had consisted of several different issuing entities. These issuing entities had been part of the PROMESA restructuring process that began in 2016. On December 6, 2022, the Fifth Amended Title III Plan of Adjustment of The Puerto Rico Highways and Transportation Authority ("PRHTA POA") became effective and concluded the debt restructuring of all AAC-insured Puerto Rico obligations under PROMESA. The consummation of the PRHTA POA followed previous plans of adjustment and qualifying modifications related to AAC's insured Puerto Rico exposure, including the Eighth Amended Plan Title III Joint Plan of Adjustment for the Commonwealth of Puerto Rico, et al. ("Eighth Amended POA") together with the Qualifying Modifications for PRIFA and CCDA ("PRIFA QM" and "CCDA QM"), respectively, in March 2022, which resolved the PROMESA restructuring process for the GO, PBA, PRIFA and CCDA issuing entities that had portions of their bonds insured by AAC; and COFINA Plan of Adjustment in February 2019, which resolved the restructuring process for the COFINA issuing entity that had portions of their bonds insured by AAC. PRHTA / CCDA PSA Creditor recoveries under the PRHTA POA were based upon the PRHTA/CCDA PSA, which was originally executed on May 5, 2021, and provides for certain consideration for holders of bonds issued by certain Commonwealth instrumentalities, PRHTA, and CCDA on account of their claims against the Commonwealth arising from such bonds ("Clawback" claims). Under the PRHTA/CCDA PSA, PRHTA creditors shared $389 of cash proceeds that was paid on July 8, 2022, once the PRHTA distribution condition was met pursuant to the Eighth Amended POA (the “Interim Distribution”). In addition, PRHTA creditors received an approximately 69% share, subject to a lifetime nominal cap of $3,698, of the Clawback Creditors' portion of the outperformance of the Commonwealth's sales and use tax ("SUT") relative to the certified 2020 Commonwealth Fiscal Plan's projections (the "Clawback CVI"). The Clawback CVI instrument was also distributed as part of the Interim Distribution on July 8, 2022. PRHTA bondholder also received new PRHTA bonds with a face amount of $1,245. Of the $1,245 in new bonds, approximately $646.4 was allocated to holders of PRHTA '68 bonds and approximately $598.6 was allocated to holders of PRHTA '98 bonds. The new PRHTA bonds were distributed to creditors on December 6, 2022, upon the effective date of the PRHTA POA. AAC and other PRHTA creditors also received restriction fees and consummation costs on the effective date of the PRHTA POA. PRHTA Interim Distribution On July 8, 2022, following satisfaction of the PRHTA distribution condition, AAC received its share of the Interim Distribution of cash and Clawback CVI related to the Ambac-insured PRHTA ’68 and ’98 bonds in satisfaction of the Clawback claims against the Commonwealth under the Eighth Amended POA. On the PRHTA POA effective date, a portion of the cash and Clawback CVI, or the proceeds thereof, were: (i) distributed to PRHTA ’98 commuting bondholders together with the new PRHTA bonds in connection with the PRHTA POA and a commutation payment from AAC in full satisfaction of in full and final discharge of Ambac’s obligations under the Ambac insurance policies or (ii) deposited into a trust, as described below, together with the new PRHTA bonds in connection with the PRHTA POA. PRHTA Effective Date Transactions On December 6, 2022, 1) all remaining outstanding AAC-insured PRHTA '68 bonds or about $4 of net par exposure were fully satisfied and eliminated via acceleration, and 2), pursuant to bondholder election, about 21% or $83 of net par exposure of AAC-insured PRHTA '98 bonds were fully satisfied and eliminated via commutation. The AAC-insured PRHTA '98 bondholders who failed to elect commutation had their bondholders’ share of plan consideration under the PRHTA POA and the interim distribution under the Eighth Amended POA deposited into a newly formed trust. These trusts with initial net par exposure of about $312 were consolidated by Ambac as further discussed in Note 12. Variable Interest Entities. Following the effective date, trust units were redeemed, reducing the PRHTA '98 net par exposure to about $178 at December 31, 2022. Since year-end, AAC-insured PRHTA exposure has been further reduced through redemptions of trusts units. Eighth Amended POA Effective Date Transactions On March 15, 2022, and pursuant to bondholder elections: (i) all of the remaining outstanding AAC-insured GO and PBA bonds or about $94 in insured par were satisfied and eliminated via commutation or acceleration and (ii) about 39% and 19% of the par of AAC's outstanding AAC-insured PRIFA and CCDA bonds, respectively, or about $172, were eliminated via commutation. The AAC-insured PRIFA and CCDA bondholders who failed to elect commutation had their respective shares of consideration available under the Commonwealth Plan and the PRIFA QM, or CCDA QM, as applicable, deposited into newly formed trusts. These trusts were consolidated by Ambac as further discussed in Note 12. Variable Interest Entities . Since the effective date, the remainder of those PRIFA and CCDA bonds belonging to bondholders who elected not to commute their AAC insurance policies and that were deposited into trusts together with the related AAC policies have all been accelerated, satisfying and eliminating all of the Ambac-insured PRIFA and CCDA bonds. Representation and Warranty Recoverable Ambac records estimated RMBS R&W subrogation recoverables for breaches of R&W by sponsors of certain RMBS transactions. For a discussion of the approach utilized to estimate RMBS R&W subrogation recoverables, see Note 2. Basis of Presentation and Significant Accounting Policies. Ambac has recorded RMBS R&W subrogation recoverables of $140, ($140 net of reinsurance) and $1,730, ($1,704 net of reinsurance) at December 31, 2022 and 2021, respectively. On December 29, 2022, AAC entered into a Settlement Agreement and Release with Nomura Credit & Capital, Inc. 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 sponsor. Reinsurance Recoverables, Including Credit Impairments: The Company uses ceded reinsurance to transfer certain insurance risk, along with premiums written and earned, to other insurance carriers that agree to share in such risks. The primary purpose of the reinsurance is to (i) protect the Company, at a cost, from losses in excess of amounts it is willing to accept, (ii) protect the Company's capital, and (iii) within the Specialty Property and Casualty Insurance operations, to manage the Company's net retention on individual risks and overall exposure to losses while providing the Company the ability to offer policies with sufficient limits to meet policyholder needs. • Within its Specialty Property and Casualty Insurance segment, the Company generally enters into quota share reinsurance agreements whereby the Company cedes to the capacity providers (reinsurers) a substantial amount (generally 70% or more) of its gross liability under all policies issued by and on behalf of the Company by the MGA/U. Ambac is exposed to the credit risk of the reinsurer, or the risk that one of its reinsurers becomes insolvent or otherwise unable or unwilling to pay policyholder claims. This credit risk is generally mitigated by either selecting well capitalized, highly rated authorized capacity providers or requiring that the capacity provider post collateral to secure the reinsured risks, which in some instances, exceeds the related reinsurance recoverable. Amounts recoverable from reinsurers are estimated in a manner consistent with the associated loss and loss adjustment expense reserves. The Company reports its reinsurance recoverables net of an allowance for amounts that are estimated to be uncollectible. Ambac’s reinsurance assets, including deferred ceded premiums and reinsurance recoverables on losses amounted to $239 at December 31, 2022. Credit exposure existed at December 31, 2022, with respect to reinsurance recoverables to the extent that any reinsurer may not be able to reimburse Ambac under the terms of these reinsurance arrangements. At December 31, 2022, there were ceded reinsurance balances payable of $39 offsetting this credit exposure. Contractually ceded reinsurance payables can only be offset against amounts owed from the same reinsurer in the event that such reinsurer is unable to meet its obligations to reimburse Ambac. To minimize its credit exposure to losses from reinsurer insolvencies, Ambac (i) is entitled to receive collateral from its reinsurance counterparties in certain reinsurance contracts and (ii) has certain cancellation rights that can be exercised by Ambac in the event of rating agency downgrades of a reinsurer (among other events and circumstances). Ambac held letters of credit and collateral amounting to $116 from its reinsurers at December 31, 2022. For those reinsurance counterparties that do not currently post collateral, Ambac's reinsurers are well capitalized, highly rated, authorized capacity providers. Additionally, while legacy liabilities from the PWIC acquisition and the three admitted carriers acquired by Everspan on January 3, 2022(the "21st Century Companies") were fully ceded to certain reinsurers, Everspan also benefits from an unlimited, uncapped indemnity from Enstar Holdings (US) and 21st Century Premier Insurance Company, respectively, to mitigate any residual risk to these reinsurers. The allowance for credit losses is based upon Ambac's ongoing review of amounts outstanding and the key indicators management uses to assess the credit quality of reinsurance recoverables are collateral posted by the reinsurers and independent rating agency credit ratings. The evaluation begins with a comparison of the fair value of collateral posted by the reinsurer to the recoverable, net of ceded premiums payable. Any shortfall of collateral posted is evaluated against the credit rating of the reinsurer to determine whether an allowance is considered necessary. For 2022, our top three reinsurers represented 84.2% of our total ceded reinsurance recoverables, and reinsurance recoverables were primarily from reinsurers with applicable ratings of A or better. The following table sets forth our three most significant reinsurers by amount of reinsurance recoverable as of December 31, 2022. Reinsurers Type of Insurance Rating (1) Reinsurance Recoverable (2) Unsecured Recoverable (3) QBE Insurance Corporation Specialty P&C A $ 41 $ 41 Assured Guaranty Re Ltd. Financial AA 30 — General Reinsurance Company Specialty P&C A++ 25 11 All other reinsurers 18 7 Total recoverables $ 115 $ 60 (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. The allowance for credit losses is based upon Ambac's ongoing review of amounts outstanding. Key indicators management uses to assess the credit quality of reinsurance recoverables are financial performance of the reinsurers, collateral posted by the reinsurers and independent rating agency credit ratings. The evaluation begins with a comparison of the fair value of collateral posted by the reinsurer to the recoverable, net of ceded premiums payable. Any shortfall of collateral posted is evaluated against our assessment of the reinsurer's financial strength, including its credit rating to determine whether an allowance is considered necessary. Ambac has uncollateralized credit exposure of $60 and $32 and has recorded an allowance for credit losses of less than a million at December 31, 2022 and December 31, 2021, respectively. The uncollateralized credit exposure includes legacy liabilities obtained from the acquisitions of PWIC and the 21st Century Companies of $45 and $30 at December 31, 2022 and December 31, 2021, respectively. Legacy liabilities are also supported by an unlimited, uncapped indemnity from Enstar Holdings (US) and 21st Century Premier Insurance Company, respectively.

Insurance Regulatory Restrictio

Insurance Regulatory Restrictions (Notes)	12 Months Ended
Insurance Regulatory Restrictions (Notes)	Dec. 31, 2022
Regulatory Assets and Liabilities Disclosure [Abstract]
Insurance Regulatory Restrictions	9. INSURANCE REGULATORY RESTRICTIONS United States AAC is domiciled in the State of Wisconsin and, as such, it is subject to the insurance laws and regulations of the State of Wisconsin (the “Wisconsin Insurance Laws”) and is regulated by the OCI as a domestic insurer. Everspan Indemnity and its wholly owned subsidiary, Everspan Insurance Company ("Everspan Insurance"), are domiciled in Arizona and are subject to the insurance laws and regulations of Arizona (the “Arizona Insurance Laws”) and are regulated by the Arizona Department of Insurance and Financial Institutions as domestic insurers. The other subsidiaries of Everspan Insurance are domiciled in various States and are therefore subject to the insurance laws and regulations of their respective States of domicile (together with the Wisconsin Insurance Laws and the Arizona Insurance Laws, the “State Insurance Laws”) and regulated by the insurance departments of those States as domestic insurers. In addition, AAC, Everspan Insurance and its subsidiaries are subject to the insurance laws and regulations of the other jurisdictions in which they are licensed and operate as foreign insurers. Insurance laws and regulations applicable to insurers vary by jurisdiction, but the insurance laws and regulations applicable to our insurance carriers generally require them to maintain minimum standards of business conduct and solvency; to meet certain financial tests; and to file policy forms, premium rate schedules and certain reports with regulatory authorities, including information concerning capital structure, ownership, financial condition (such as risk-based capital), corporate governance and enterprise risk. AAC, because it is a financial guarantee insurer, is not subject to risk-based capital requirements. As a run-off financial guarantor, AAC has been operating under the Stipulation and Order required by OCI. OCI is developing OCI's Runoff Capital Framework to assist with decisioning related to capital and liquidity management at AAC. Regulated insurance companies are also required to file quarterly and annual statutory financial statements in each jurisdiction in which they are licensed. The State Insurance Laws also require prior approval (or non-disapproval) of certain transactions between an insurance carrier and its affiliates. The level of supervisory authority that may be exercised by non-domiciliary insurance regulators varies by jurisdiction. Generally, however, non-domiciliary regulators are authorized to suspend or revoke the insurance license they issued and to impose restrictions on that license in the event that laws or regulations are breached by a regulated insurance company or in the event that continued or unrestricted licensing of the regulated insurance company constitutes a “hazardous condition” (or meets a similar standard) in the opinion of the non-domiciliary regulator. The domiciliary regulators have primary regulatory authority, including with respect to the initiation and administration of rehabilitation or liquidation proceedings. Additionally, the accounts and operations of AAC and Everspan are subject to individual periodic comprehensive financial examinations by their domestic regulators, and may be examined collectively by the lead regulator of the affiliated insurance company group. In December 2020, Everspan Insurance completed its re-domestication from Wisconsin to Arizona and obtained broad authority to write property and casualty insurance (while contemporaneously surrendering its authority to write financial guaranty insurance) in Arizona. Everspan Insurance thereafter sought similar amendments to its certificates of authority in all other states. Everspan Insurance and its subsidiaries (Providence Washington Insurance Company, Greenwood Insurance Company, Consolidated National Insurance Company and 21st Century Auto Insurance Company of New Jersey) are subject to risk-based capital requirements. Everspan Indemnity was formed in 2020 as a domestic surplus lines insurer in Arizona and, accordingly, is eligible to write property and casualty insurance as an excess and surplus lines insurance in all states by virtue of the U.S. Nonadmitted and Reinsurance Reform Act of 2010. Everspan Indemnity owns 100% of Everspan Insurance. Everspan Indemnity issued its first policies in May 2021. All of Ambac's insurance subsidiaries are in compliance with the minimum capital and surplus levels required under the State Insurance Laws required to transact all business written to date. Our Insurance Distribution businesses, like some other managing general agents, brokerages and program administrators, may be subject to licensing requirements and regulation by insurance regulators in various states in which they conduct business. In addition to the legal restrictions applicable to AAC as described herein, pursuant to the terms of the Settlement Agreement and the Stipulation and Order, AAC must seek prior approval by OCI of certain corporate actions. The Settlement Agreement and Stipulation and Order include covenants which restrict the operations of AAC. The Settlement Agreement will remain in force until the surplus notes that were issued pursuant to the Settlement Agreement have been redeemed, repurchased or repaid in full. The Stipulation and Order will remain in force for so long as OCI determines it to be necessary. Certain of the restrictions in the Settlement Agreement may be waived with the approval of the OCI and/or the requisite percentage of holders of AAC's surplus notes. OCI's Runoff Capital Framework, when implemented, will 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. Nevertheless, in the event that the OCI Runoff Capital Framework were to indicate that AAC is in a capital deficit position, OCI cannot require AFG or any other Ambac entity to contribute capital to or otherwise support AAC. Although not domiciled in New York, AAC is nevertheless subject to the New York insurance law governing financial guarantee insurers. New York’s comprehensive financial guarantee insurance law defines the scope of permitted financial guarantee insurance and governs the conduct of business of all financial guarantors licensed to do business in New York, including AAC. The New York financial guarantee insurance law also establishes single and aggregate risk limits with respect to insured obligations insured by financial guarantee insurers. Such single risk limits are specific to the type of insured obligation (for example, municipal or asset-backed). Under the aggregate limits, policyholders’ surplus and contingency reserves must at least equal a percentage of aggregate net liability that is equal to the sum of various percentages of aggregate net liability for various categories of specified obligations. At December 31, 2022, AAC is in compliance with applicable aggregate risk limits and applicable single risk limits. The financial statements of AAC and Everspan are prepared on the basis of accounting practices prescribed or permitted by the State Insurance Laws and the actions of regulatory authorities thereunder. AAC and Everspan use such statutory accounting practices prescribed or permitted by the applicable regulatory authorities for determining and reporting their financial condition and results of operations, including for determining solvency under the State Insurance Laws. The States in which AAC and Everspan are domiciled have adopted the National Association of Insurance Commissioners (“NAIC”) accounting practices and procedures manual (“NAIC SAP”) as a component of prescribed practices as codified in each State’s applicable law or regulation. Statutory policyholder surplus differs from stockholder's equity determined under GAAP principally due to statutory accounting rules that treat financial guarantee premiums and loss reserves, investments, consolidation of subsidiaries or variable interest entities and surplus notes differently. The following are details of statutory surplus for AAC and Everspan Indemnity: • AAC’s statutory policyholder surplus was $598 at December 31, 2022, as compared to $757 as of December 31, 2021. • Everspan Indemnity has statutory policyholder surplus of $107 as of December 31, 2022 as compared to $106 as of December 31, 2021. The OCI has prescribed additional practices and has permitted accounting practices for AAC. As a result of the prescribed and permitted practices discussed below, AAC’s statutory surplus at December 31, 2022 and 2021 was higher by $90 and lower by $5, respectively, than if AAC had reported such amounts in accordance with NAIC SAP. Everspan Indemnity and its subsidiaries do not have permitted or additional prescribed practices at December 31, 2022. The Arizona Department of Insurance and Financial Institutions has permitted accounting practices for Everspan Indemnity and Everspan Insurance at December 31, 2021 As a result of the permitted practice discussed below, Everspan Indemnity's statutory surplus at December 31, 2021 was higher by $18 than if Everspan had reported such amounts with NAIC SAP. Everspan had no additional prescribed practices as at December 31, 2021. Additional Prescribed Accounting Practices AAC: OCI has prescribed the following accounting practices that differ from NAIC SAP for AAC: • Paragraph 8 of Statement of Statutory Accounting Principles No. 60 “Financial Guaranty Insurance” allows for a deduction from loss reserves for the time value of money by application of a discount rate equal to the average rate of return on the admitted assets of the financial guaranty insurer as of the date of the computation of the reserve. The discount rate shall be adjusted at the end of each calendar year. Additionally, in accordance with paragraph 13.e of Statutory Accounting Principles No. 97 "Investments in Subsidiary, Controlled and Affiliated Entities" and paragraph 8 of Statutory Accounting Principles No. 5R “Liabilities, Contingencies and Impairments of Assets - Revised”, AAC records probable losses on its subsidiaries for which it guarantees their obligations. AAC also discounts probable losses on guarantees of subsidiary obligations using a discount rate equal to the average rate of return on its admitted assets. AAC’s average rates of return on its admitted assets at December 31, 2022 and 2021 were 3.22% and 5.28%, respectively. OCI has directed AAC to utilize a prescribed discount rate of 5.10% for the purpose of discounting both its loss reserves and its probable losses on subsidiary guarantees. • Paragraph 4 of Statement of Statutory Accounting Principles No. 41 “Surplus Notes” (“SSAP 41”) states that proceeds received by the issuer of surplus notes must be in the form of cash or other admitted assets having readily determinable values and liquidity satisfactory to the commissioner of the state of domicile. Under statutory accounting principles, surplus notes issued in conjunction with commutations or the settlement of obligations would be valued at zero upon issuance pursuant to paragraph 4, SSAP 41. OCI has directed the Company to record surplus notes issued in connection with commutations or the settlement of obligations at full par value upon issuance. The surplus notes issued have a claim against surplus senior to the preferred and common shareholders. • Paragraph 35 of Statement of Statutory Accounting Principles No. 43R ”Loan-backed and Structured Securities” states that when an other-than-temporary impairment ("OTTI") has occurred, the amount of the OTTI recognized as a realized loss shall equal the difference between the investment’s amortized cost basis and the present value of cash flows expected to be collected, discounted at the loan-backed or structured security’s effective interest rate. From June 11, 2014 to February 12, 2018, OCI had directed AAC to not evaluate for OTTI investments in AAC insured securities with designated policies that were allocated to a segregated account of AAC in rehabilitation overseen by OCI, and required all such investments be reported at amortized cost regardless of its NAIC risk designation. Permitted Accounting Practices AAC: OCI has allowed the following permitted practice for AAC: • Wisconsin accounting practices for changes to contingency reserves differ from NAIC SAP. Under NAIC SAP, contributions to and releases from the contingency reserve are recorded via a direct charge or credit to surplus. Under the Wisconsin Administrative Code, contributions to and releases from the contingency reserve are to be recorded through underwriting income. AAC received permission from OCI to record contributions to and releases from the contingency reserve, in accordance with NAIC SAP. Everspan: The Arizona Department of Insurance and Financial Institutions has allowed the following permitted practice for Everspan: • Paragraph 8 of Statement of Statutory Accounting Principles No. 97 “Investment in Subsidiary, Controlled and Affiliated Entities” (“SSAP 97”) states Investments in US insurance Subsidiary, Controlled and Affiliated entities shall be recorded based on the underlying audited statutory equity of the respective entity's financial statements adjusted for any unamortized goodwill. Everspan has received permission from the Arizona Department of Insurance and Financial Institutions to admit its investment at December 31, 2021 of its wholly owned subsidiary, Providence Washington Insurance Company. Providence Washington Insurance Company received a waiver from its regulator to file a statutory audit report issued for the year ended December 31, 2021. United Kingdom The Prudential Regulatory Authority (“PRA”) and Financial Conduct Authority (“FCA”) (and their predecessor regulator the Financial Services Authority (“FSA”)) are the dual statutory regulator responsible for regulating the financial services industry in the United Kingdom, with the purpose of maintaining confidence in the U.K. financial system, providing public understanding of the system, securing the proper degree of protection for consumers and helping to reduce financial crime. These regulators have exercised significant oversight of Ambac UK since 2008, after Ambac, AAC and Ambac UK began experiencing financial stress. In 2009, Ambac UK’s license to write new business was curtailed by the FSA and the insurance license was limited to undertaking only run-off related activity. As such, Ambac UK is authorized to run-off its credit, suretyship and financial guarantee insurance portfolio in the United Kingdom. The PRA requires that non-life insurance companies such as Ambac UK maintain a margin of solvency at all times in respect of the liabilities of the insurance company, the calculation of which depends on the type and amount of insurance business a company writes. These solvency requirements were amended on January 1, 2016, in order to implement the European Union's "Solvency II" directive on risk-based capital. Ambac UK had previously been in a capital shortfall position as compared to these solvency capital requirements, but has met the requirements since December 31, 2021. Dividend Restrictions, Including Contractual Restrictions State Insurance Regulators prescribe rules that determine if AAC and Everspan may declare dividends. In addition, AAC and Everspan are subject to certain restrictions in their respective articles of incorporation with regards to the payment of dividends. Board action authorizing a distribution by an insurance company must generally be reported to the applicable domiciliary regulator prior to payment. In addition, State Insurance Laws generally require regulatory approval for the payment of extraordinary dividends, which are distributions in amounts that would exceed certain thresholds, such as a percentage of surplus or net income for the prior year or number of years. Everspan does not have sufficient earned surplus at this time to pay ordinary dividends under the State Insurance Laws. Furthermore, certain subsidiaries of Everspan Insurance are restricted from paying dividends to Everspan Insurance until 2025 or later pursuant to the regulatory orders approving the acquisition of those subsidiaries, unless specifically approved by the applicable domiciliary regulator. Due to losses experienced by AAC, it has been unable to pay ordinary dividends to AFG since 2008 and will be unable to pay common dividends in 2023 without the prior consent of the OCI, which is extremely unlikely. AAC’s ability to pay dividends is further restricted by the Settlement Agreement (as described below), by the terms of its AMPS (as described below) and by the Stipulation and Order, and may be affected by OCI's Runoff Capital Framework, although OCI's Runoff Capital Framework has not yet been implemented and we cannot predict the results or implications thereof. See Note 1. Background and Business Description for further information. Accordingly, AAC's ability to pay dividends to AFG and the timing thereof remain subject to substantial uncertainty. • Pursuant to the Settlement Agreement, AAC may not make any “Restricted Payment” (which includes dividends from AAC to Ambac) in excess of $5 in the aggregate per annum, other than Restricted Payments from AAC to Ambac in an amount up to $8 per annum solely to pay operating expenses of Ambac. Concurrent with making any such Restricted Payment, a pro rata amount of AAC's surplus notes would also need to be redeemed at par. • Under the terms of AAC’s AMPS, dividends may not be paid on the common stock of AAC unless all accrued and unpaid dividends on the AMPS for the then current dividend period have been paid, provided, that dividends on the common stock may be made at all times for the purpose of, and only in such amounts as are necessary for, enabling Ambac (i) to service its indebtedness for borrowed money as such payments become due or (ii) to pay its operating expenses. If dividends are paid on the common stock as provided in the prior sentence, dividends on the AMPS become cumulative until the date that all accumulated and unpaid dividends have been paid on the AMPS. • The Stipulation and Order requires OCI approval for the payment of any dividend or distribution on the common stock of AAC. • OCI's Runoff Capital Framework may be implemented in the near term. While OCI's Runoff Capital Framework is not complete and we cannot predict the results and implications thereof, it is possible that OCI's Runoff Capital Framework and decisions based thereon may affect AAC's ability to reduce financial leverage or to pay dividends to AFG. Nevertheless, in the event that the OCI Runoff Capital Framework were to indicate that AAC is in a capital deficit position, OCI cannot require AFG or any other Ambac entity to contribute capital to or otherwise support AAC. UK law prohibits Ambac UK from declaring a dividend to its shareholders unless it has “profits available for distribution.” The determination of whether a company has profits available for distribution is based on its accumulated realized profits less its accumulated realized losses. While the UK insurance regulatory laws impose no statutory restrictions on a general insurer’s ability to declare a dividend, the PRA’s and FCA’s rules governing capital extraction by insurance firms in run off require Ambac UK to consider its future capital requirements over a 3 to 5 year period in both base case and downside stress scenarios before declaring a dividend. Further, the FSA

Derivative Instruments

Derivative Instruments	12 Months Ended
Derivative Instruments	Dec. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	10. 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 December 31, 2022 and 2021. Gross Gross Net Amounts Gross Amount Net Amount December 31, 2022: Derivative Assets: Interest rate swaps $ 27 $ — $ 27 $ — $ 27 Warrants 1 — 1 — 1 Total non-VIE derivative assets $ 28 $ — $ 27 $ — $ 27 Derivative Liabilities: Interest rate swaps 38 — 38 38 — Total non-VIE derivative liabilities $ 38 $ — $ 38 $ 38 $ — Variable Interest Entities Derivative Assets: Interest rate swaps $ 190 $ — $ 190 $ — $ 190 Currency swaps 49 — 49 — 49 Total VIE derivative assets $ 239 $ — $ 239 $ — $ 239 Variable Interest Entities Derivative Liabilities: Interest rate swaps $ 1,048 $ — $ 1,048 $ — $ 1,048 Total VIE derivative liabilities $ 1,048 $ — $ 1,048 $ — $ 1,048 December 31, 2021: Derivative Assets: Interest rate swaps $ 76 $ — $ 76 $ — $ 76 Total non-VIE derivative assets $ 76 $ — $ 76 $ — $ 76 Derivative Liabilities: Credit derivatives $ — $ — $ — $ — $ — Interest rate swaps 94 — 94 93 1 Total non-VIE derivative liabilities $ 95 $ — $ 95 $ 93 $ 2 Variable Interest Entities Derivative Assets: Currency swaps $ 38 $ — $ 38 $ — $ 38 Total VIE derivative assets $ 38 $ — $ 38 $ — $ 38 Variable Interest Entities Derivative Liabilities: Interest rate swaps $ 1,940 $ — $ 1,940 $ — $ 1,940 Total VIE derivative liabilities $ 1,940 $ — $ 1,940 $ — $ 1,940 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 Consolidated Balance Sheets. The amounts representing the right to reclaim cash collateral and posted margin, recorded in “Other assets” were $6 and $13 as of December 31, 2022 and 2021, respectively. There were no amounts held representing an obligation to return cash collateral as of December 31, 2022 and 2021. The following tables summarize the location and amount of gains and losses of derivative contracts in the Consolidated Statements of Total Comprehensive Income (Loss) for the years ended December 31, 2022, 2021 and 2020: Location of Gain (Loss) Recognized Amount of Gain (Loss) Recognized in Consolidated Statement of Total Comprehensive Income (Loss) – 2022 2021 2020 Non-VIE derivatives: Credit derivatives Net gains (losses) on derivative contracts $ — $ — $ — Interest rate swaps Net gains (losses) on derivative contracts 65 13 (9) Warrants Net gains (losses) on derivative contracts 1 — — Futures contracts Net gains (losses) on derivative contracts 62 9 (41) Total Non-VIE derivatives 129 22 (50) Variable Interest Entities: Currency swaps Income (loss) on variable interest entities 24 2 (6) Interest rate swaps Income (loss) on variable interest entities 541 (152) (138) Total Variable Interest Entities 565 (150) (144) Total derivative contracts $ 694 $ (128) $ (193) Interest Rate Derivatives Ambac, through its subsidiary Ambac Financial Services (“AFS”), uses interest rate swaps, US Treasury futures contracts and other derivatives, to provide a partial economic hedge against the effects of rising interest rates elsewhere in the Legacy Financial Guarantee Insurance segment, including on Ambac’s financial guarantee exposures. 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 December 31, 2022 and 2021, the notional amounts of AFS's derivatives are as follows: Notional - December 31, Type of Derivative 2022 2021 Interest rate swaps—pay-fixed/receive-variable $ 989 $ 1,275 US Treasury futures contracts—short — 470 Interest rate swaps—receive-fixed/pay-variable 337 185 Other Derivatives: The principal notional outstanding for credit derivative contracts was $0 and $201 as of December 31, 2022 and December 31, 2021, respectively. As of December 31, 2022 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 for VIE derivatives outstanding as of December 31, 2022 and 2021, were as follows: Notional - December 31, Type of VIE Derivative 2022 2021 Interest rate swaps—receive-fixed/pay-variable $ 1,573 $ 1,221 Interest rate swaps—pay-fixed/receive-variable 887 1,069 Currency swaps 176 272 Contingent Features in Derivatives Related to Ambac Credit Risk Ambac’s over-the-counter interest rate swaps are centrally cleared when eligible. Certain interest rate swaps remain with professional swap-dealer counterparties and direct customer counterparties. These non-cleared swaps are generally 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 December 31, 2022 and 2021, the net liability fair value of derivative instruments with contingent features linked to Ambac’s own credit risk was $38 and $93, respectively, related to which Ambac had posted cash and securities as collateral with a fair value of $54 and $109, 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 December 31, 2022, 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	12 Months Ended
Intangible Assets	Dec. 31, 2022
Statement of Financial Position [Abstract]
Goodwill and Intangible Assets Disclosure	11. 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. December 31, 2022 2021 Beginning balance $ 46 $ 46 Business acquisitions 15 — Impairments — — Ending balance $ 61 $ 46 Intangible asset and accumulated amortization are included in the Consolidated Balance Sheets, as shown below. December 31, 2022 2021 Finite-lived Intangible Assets: Insurance intangible: Gross carrying value $ 1,247 $ 1,278 Accumulated amortization 981 958 Net insurance intangible asset 266 320 Other intangibles: Gross Carrying value 52 36 Accumulated amortization 6 3 Net other intangible assets 47 33 Total finite-lived intangible assets $ 312 $ 353 Indefinite-lived Intangible Assets: Insurance licenses $ 14 $ 9 Total intangible assets $ 326 $ 362 Amortization Expense: Amortization expense is included in the Consolidated Statements of Total Comprehensive Income (Loss), as shown below. Year ended December 31, 2022 2021 2020 Insurance intangible $ 44 52 $ 57 Other intangibles 3 3 — Total $ 47 $ 55 $ 57 The estimated future amortization expense for finite-lived intangible assets is as follows: Amortization Expense Insurance Intangible Asset (1) Other Intangible Assets (1) Total 2023 $ 27 $ 4 $ 31 2024 25 4 29 2025 23 4 27 2026 21 3 25 2027 19 3 23 Thereafter 149 28 178

Variable Interest Entities

Variable Interest Entities	12 Months Ended
Variable Interest Entities	Dec. 31, 2022
Accounting Policies [Abstract]
Variable Interest Entity Disclosure	12. VARIABLE INTEREST ENTITIES Ambac, with its subsidiaries, has engaged in transactions with variable interest entities ("VIEs") in various capacities. • AAC and Ambac UK provide financial guarantees for various debt obligations issued by special purpose entities, including VIEs ("FG VIEs"); • Ambac sponsors special purpose entities that issued notes to investors for various purposes; and • AAC and Ambac UK invest in collateralized debt obligations, mortgage-backed and other asset-backed securities issued by VIEs and their ownership interest is generally insignificant to the VIE and/or Ambac does not have rights that direct the activities that are most significant to such VIE. FG VIEs AAC and Ambac UK provide financial guarantees in respect of assets held or debt obligations of VIEs. AAC and Ambac UK’s primary variable interest exists through this financial guarantee insurance. The transaction structures provide certain financial protection to Ambac. Generally, upon deterioration in the performance of a transaction or upon an event of default as specified in the transaction legal documents, AAC or Ambac UK will obtain certain control rights that enable them to remediate losses. These rights may enable them to direct the activities of the entity that most significantly impact the entity’s economic performance. Under the Stipulation and Order, AAC is required to obtain OCI approval with respect to the exercise of certain significant control rights in connection with policies that had previously been allocated to the Segregated Account, which was established in 2010 to segregate certain segments of AAC’s liabilities for purposes of the rehabilitation proceeding overseen by the Wisconsin Insurance Commissioner in order to facilitate an orderly run-off and/or settlement of the liabilities allocated to the Segregated Account (which ceased to exist in 2018). Accordingly, AAC does not have the right to direct the most significant activities of those FG VIEs. • We determined that AAC or Ambac UK generally have the obligation to absorb a FG VIE's expected losses given that they have issued financial guarantees supporting certain liabilities (and in some cases certain assets). As further described below, Ambac consolidates certain FG VIEs in cases where we also have the power to direct the activities that most significantly impact the VIE’s economic performance due to one or more of the following: (i) the transaction experiencing deterioration and breaching performance triggers, giving AAC or Ambac UK the ability to exercise certain control rights, (ii) AAC or Ambac UK being involved in the design of the VIE and receiving control rights from its inception, such as may occur from loss remediation activities, or (iii) the transaction not experiencing deterioration, however due to the passive nature of the VIE, AAC or Ambac UK's contingent control rights upon a future breach of performance triggers is considered to be the power over the most significant activity. • A VIE is generally deconsolidated in the period that AAC or Ambac UK no longer has such control rights, which could occur in connection with the execution of remediation activities on the transaction or amortization of insured exposure, either of which may reduce the degree of control over a VIE. • Assets and liabilities of FG VIEs that are consolidated are reported within Variable interest entity assets or Variable interest entity liabilities on the Consolidated Balance Sheets. • The election to use the fair value option is made on an instrument by instrument basis. Generally, Ambac has elected the fair value option for consolidated FG VIE financial assets and financial liabilities, except in cases where AAC or Ambac UK was involved in the design of the VIE and was granted control rights at its inception. ◦ When the fair value option is elected, changes in the fair value of the FG VIE's financial assets and liabilities are reported within Income (loss) on variable interest entities in the Consolidated Statements of Total Comprehensive Income (Loss), except for the portion of the total change in fair value of financial liabilities caused by changes in the instrument-specific credit risk which is presented separately in Other comprehensive income (loss). ◦ In cases where the fair value option has not been elected, the FG VIE's invested assets are fixed maturity securities and are classified as either available-for-sale or trading as defined by the Investments - Debt Securities Topic of the ASC. Available-for-sale assets are reported in the financial statements at fair value with unrealized gains and losses reflected in Accumulated Other Comprehensive Income (Loss) in Stockholders' Equity. Trading assets are reported at fair value with unrealized gains and losses reflected within net income. The financial liabilities of these FG VIEs consist of long term debt obligations and are carried at par less unamortized discount. Income from the FG VIE's securities (including investment income, realized gains and losses and credit impairments as applicable) and interest expense on long term debt are reported within Income (loss) on variable interest entities in the Consolidated Statements of Total Comprehensive Income (Loss). • Upon initial consolidation of a FG VIE, Ambac recognizes a gain or loss in earnings for the difference between: (i) the fair value of the consideration paid, the fair value of any non-controlling interests and the reported amount of any previously held interests and (ii) the net amount, as measured on a fair value basis, of the assets and liabilities consolidated. Upon deconsolidation of a FG VIE, Ambac recognizes a gain or loss for the difference between: (i) the fair value of any consideration received, the fair value of any retained non-controlling investment in the VIE and the carrying amount of any non-controlling interest in the VIE and (ii) the carrying amount of the VIE’s assets and liabilities. Gains or losses from consolidation and deconsolidation that are reported in earnings are reported within Income (loss) on variable interest entities on the Consolidated Statements of Total Comprehensive Income (Loss). • The impact of consolidating such FG VIEs on Ambac’s balance sheet is the elimination of transactions between the consolidated FG VIEs and AAC or Ambac UK and the inclusion of the FG VIE’s third party assets and liabilities. For a financial guarantee insurance policy issued to a consolidated VIE, Ambac does not reflect the financial guarantee insurance policy in accordance with the related insurance accounting rules under the Financial Services — Insurance Topic of the ASC. Consequently, upon consolidation, Ambac eliminates the insurance assets and liabilities associated with the policy from the Consolidated Balance Sheets. Such insurance assets and liabilities may include premium receivables, reinsurance recoverable, deferred ceded premium, subrogation recoverable, unearned premiums, loss and loss adjustment expense reserves, ceded premiums payable and insurance intangible assets. For investment securities owned by AAC or Ambac UK that are debt instruments issued by the VIE, the associated debt and investment balances are eliminated upon consolidation. FG VIEs which are consolidated may include recourse and non-recourse liabilities. FG VIEs' liabilities that are insured by AAC or Ambac UK are with recourse, because the AAC or Ambac UK guarantees the payment of principal and interest in the event the issuer defaults. FG VIEs' liabilities that are not insured by the AAC or Ambac UK are without recourse, because AAC or Ambac UK has not issued a financial guarantee and is under no obligation for the payment of principal and interest of these instruments. AAC or Ambac UK’s economic exposure to consolidated FG VIEs is limited to the financial guarantees issued for recourse liabilities and any additional variable interests held by them. Additionally, AAC or Ambac UK’s general creditors, other than those specific policy holders which own the VIE debt obligations, do not have rights with regard to the assets of the VIEs. Ambac evaluates the net income effects and earnings per share effects to determine attributions between AAC or Ambac UK and non-controlling interests as a result of consolidating a VIE. Ambac has determined that the net income and earnings per share effect of consolidated FG VIEs are attributable to AAC or Ambac UK’s interests through financial guarantee premium and loss payments with the VIE. The following table summarizes the carrying values of assets and liabilities, along with other supplemental information related to VIEs that are consolidated as a result of financial guarantees of Ambac UK and AAC: December 31, 2022 2021 Ambac UK Ambac Assurance Total VIEs Ambac UK Ambac Assurance Total VIEs ASSETS: Fixed maturity securities, at fair value: Corporate obligations, fair value option $ 1,828 $ — $ 1,828 $ 3,320 $ — $ 3,320 Municipal obligations, trading — 43 43 — — — Municipal obligations, available-for-sale (1) — 96 96 — 136 136 Total FG VIE fixed maturity securities, at fair value 1,828 139 1,967 3,320 136 3,455 Restricted cash 1 16 17 1 1 2 Loans, at fair value (2) 1,829 — 1,829 2,718 — 2,718 Derivative assets 239 — 239 38 — 38 Other assets — 2 2 — 2 2 Total FG VIE assets $ 3,896 $ 157 $ 4,054 $ 6,077 $ 139 $ 6,216 LIABILITIES: Long-term debt: Long-term debt, at fair value (3) $ 2,788 $ — $ 2,788 $ 4,056 $ — $ 4,056 Long-term debt, at par less unamortized discount — 319 319 — 160 160 Total long-term debt 2,788 319 3,107 4,056 160 4,216 Derivative liabilities 1,048 — 1,048 1,940 — 1,940 Other liabilities — 5 5 — — — Total FG VIE liabilities $ 3,836 $ 324 $ 4,160 $ 5,996 $ 160 $ 6,156 Number of FG VIEs consolidated 5 4 9 5 1 6 (1) Available-for-sale FG VIE fixed maturity securities consist of municipal obligations with an amortized cost basis of $99 and $106 at December 31, 2022 and December 31, 2021, respectively. At December 31, 2022, there were $1 aggregate gross gains and $(4) aggregated gross losses. At December 31, 2021, there were aggregate gross unrealized gains of $29. All such securities had contractual maturities due after ten years as of December 31, 2022. (2) The unpaid principal balances of loan assets carried at fair value were $1,977 and $2,363 as of December 31, 2022 and 2021, respectively. (3) The unpaid principal balances of long-term debt carried at fair value were $3,064 and $3,579 as of December 31, 2022 and 2021, respectively. The following schedule details the components of Income (loss) on variable interest entities for the affected periods: Year ended December 31, 2022 2021 2020 Net change in fair value of VIE assets and liabilities reported under the fair value option $ — $ 4 $ (1) Less: Credit risk changes of fair value option long-term debt reported through other comprehensive income (loss) (1) 1 (1) Net change in fair value of VIE assets and liabilities reported in earnings under the fair value option (1) 5 (3) Investment income (loss) (4) 6 7 Net realized investment gains (losses) on available-for-sale securities 2 2 8 Interest expense on long-term debt carried at par less unamortized cost (12) (6) (6) Other expenses (1) (1) — Gain (loss) from consolidating VIEs 37 — — Income (loss) on variable interest entities $ 21 $ 7 $ 5 As further discussed in Note 8. Insurance Contracts , in connection with the Puerto Rico restructuring, three new trusts were established for the year ended December 31, 2022. Ambac was required to consolidate these trusts which resulted in a combined gain of $37. Including these new trusts, Ambac consolidated three and zero FG VIEs for the years ended December 31, 2022 and 2021, respectively. Ambac did not deconsolidate any FG VIEs for the years ended December 31, 2022 and 2021. 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 December 31, 2022 and 2021: Carrying Value of Assets and Liabilities Maximum (1) Insurance (2) Insurance (3) Net Derivative (Liabilities) (4) December 31, 2022: Global structured finance: Mortgage-backed—residential $ 2,559 $ 266 $ 400 $ — Other consumer asset-backed 652 6 225 — Other 430 2 2 1 Total global structured finance 3,642 274 628 1 Global public finance 17,997 216 212 — Total $ 21,639 $ 490 $ 840 $ 1 December 31, 2021: Global structured finance: Mortgage-backed—residential $ 3,265 $ 1,929 $ 521 $ — Other consumer asset-backed 788 17 234 — Other 826 3 10 5 Total global structured finance 4,879 1,949 765 5 Global public finance 20,233 246 257 — Total $ 25,112 $ 2,195 $ 1,023 $ 5 (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 adjustment 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 credit derivative contracts and interest rate swaps on Ambac’s Consolidated Balance Sheets. Ambac Sponsored Non-consolidated VIEs

Long-Term Debt (Notes)

Long-Term Debt (Notes)	12 Months Ended
Long-Term Debt (Notes)	Dec. 31, 2022
Debt Disclosure [Abstract]
Long-term Debt	13. LONG-TERM DEBT Long-term debt outstanding, excluding VIE long-term debt, was as follows: December 31, 2022 2021 Par Value Unamortized Discount Carrying Value Par Value Unamortized Discount Carrying Value Ambac Assurance: 5.1% Surplus Notes $ 519 $ (42) $ 477 $ 785 $ (56) $ 729 Sitka AAC Note — — $ — 1,175 (21) 1,154 Tier 2 Notes 146 — 146 333 — 333 Ambac UK Debt 41 (25) 16 41 (26) 15 Long-term debt $ 706 $ (67) $ 639 $ 2,334 $ (104) $ 2,230 Aggregated annual maturities of non-VIE long-term debt obligations (based on scheduled maturity dates as further discussed below) are as follows: 2023 $ 665 (1), (2) 2024 — 2025 — 2026 — 2027 — Thereafter 41 Total $ 706 (1) Surplus Notes had a scheduled maturity date of June 7, 2020. OCI declined the request of Ambac Assurance to pay the principal amount of the surplus notes, plus all accrued and unpaid interest thereon, on June 7, 2020, June 7, 2021 and June 7, 2022. As a result, the payment date for principal of the surplus notes was extended until OCI grants approval to make the payment. Interest will accrue, compounded on each anniversary of the original scheduled payment date or scheduled maturity date, on any unpaid principal or interest through the actual date of payment at 5.1% per annum. Included in the table above is the potential principal payment at the next scheduled payment date of June 7, 2023. (2) Includes $146 of Tier 2 Notes, as more fully described in Note 1. Background and Business Description, which were fully redeemed on January 15, 2023. Surplus Notes Ambac Assurance's surplus notes, with a par amount of $519 and $785 at December 31, 2022 and 2021, respectively, had a scheduled maturity of June 7, 2020, which has been extended until OCI grants approval to make the payment. During the year ended December 31, 2022, surplus notes with aggregate par amount of $266 were acquired and extinguished. The discount on surplus notes outstanding as of December 31, 2022, is being accreted into income at a weighted average effective interest rate of 7.0%. Ambac can provide no assurance as to when surplus note principal and interest payments will be made. If OCI does not approve payments on or the acquisition of surplus notes over time, the ongoing accretion of interest on the notes may impair AAC's ability to extinguish the notes in full. Surplus notes are subordinated in right of payment to policyholder and other claims. Sitka AAC Note The Sitka AAC Note, issued in connection with the Secured Note Refinancing on July 6, 2021, was wholly redeemed effective October 29, 2022, as a result of the BOA Settlement Payment as more fully described in Note 1. Background and Business Description. Interest on the Sitka AAC Note was payable quarterly (on the last day of each quarter beginning with September 30, 2021) at an annual rate of 3-month U.S. Dollar LIBOR + 4.50%, subject to a 0.75% LIBOR floor. The discount on Sitka AAC Note was being accreted into income at an effective interest rate of 5.7% Tier 2 Notes The Tier 2 Notes, issued on February 12, 2018, were partially redeemed on October 29, 2022, as a result of the BOA Settlement Payment as more fully described in Note 1. Background and Business Description. The Tier 2 Notes had a par value of $146 and $333 (including paid-in-kind interest of $49 and $93) at December 31, 2022 and 2021, respectively, and had a legal maturity of February 12, 2055. Interest on the Tier 2 Notes was at an annual rate of 8.50%. Other than upon payment of principal at redemption or maturity, interest payments were not due in cash on interest payment dates and were paid-in-kind and compounded on the last day of each calendar quarter. The Tier 2 Notes were recorded at a discount to par as any consideration paid that was directly related to the issuance of the Tier 2 Notes was capitalized and was part of the effective yield calculation. Ambac accreted the discount on the Tier 2 Notes into earnings at an effective interest rate of 9.9% based on the projected redemption at the date of issuance. The discount had been fully accreted as of December 31, 2020. The Tier 2 Notes were secured by recoveries from the RMBS Litigations in excess of $1,600 and subject to mandatory redemption upon: (i) receipt of recoveries from the RMBS Litigations in excess of $1,600 ("Tier 2 Net Proceeds") and (ii) payment of principal or interest on AAC surplus notes. Promptly, and in any event within five business days after the receipt (whether directly or indirectly) of Tier 2 Net Proceeds, AAC was required to deposit an amount equal to the Tier 2 Net Proceeds to a collateral account. As described in Note 1. Background and Business Description, the Tier 2 Notes were fully redeemed effective January 15, 2023 as a result of the Nomura Settlement Payment. Ambac UK Debt The Ambac UK debt, issued in connection with the commutation of its exposure with respect to Ballantyne Re plc on June 18, 2019, has a par value of $41 and $41 at December 31, 2022 and 2021, and a legal maturity of May 2, 2036. Interest on the Ambac UK debt is at an annual rate of 0.00%. The Ambac UK debt was recorded at its fair value at the date of issuance. The discount on the debt is currently being accreted into income at an effective interest rate of 7.4%. Variable Interest Entities, Long-term Debt The variable interest entity notes were issued by consolidated VIEs. Ambac is the primary beneficiary of the VIEs as a result of providing financial guarantees on certain of the VIEs obligations. Consequently, Ambac has consolidated these variable interest entity notes and all other assets and liabilities of the VIEs. Ambac is not primarily liable for the debt obligations of these entities. Ambac would only be required to make payments on these debt obligations in the event that the issuer defaults on any principal or interest due and to the extent such obligations are guaranteed by Ambac. The total unpaid principal amount of outstanding long-term debt associated with VIEs consolidated as a result of the financial guarantee provided by Ambac was $3,388 and $3,739 as of December 31, 2022 and 2021, respectively. As of December 31, 2022 and 2021, the ranges of final maturity dates of the outstanding long-term debt

Revenue from Contract with Cust

Revenue from Contract with Customer	12 Months Ended
Revenue from Contract with Customer	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer	14. REVENUES FROM CONTRACTS WITH CUSTOMERS The following table presents the revenues recognized in accordance with the Revenue from Contracts with Customers Topic of the ASC disaggregated by policy type for the year ended December 31, 2022 and 2021: Year ended December 31, 2022 2021 Employer stop loss $ 9 $ 8 Affinity products 19 18 Commercial Auto, Marine and Other 3 — Total 31 $ 26 During the year ended December 31, 2022, the amount of revenue recognized related to performance obligations satisfied in a previous period, inclusive of changes due to estimates was approximately $6. Contract Assets and Liabilities The balances of contract assets and contract liabilities with customers were as follows: December 31, 2022 2021 Premiums and commissions receivable $ 7 $ 2 Contract assets 5 4 Contract liabilities 1 1

Comprehensive Income

Comprehensive Income	12 Months Ended
Comprehensive Income	Dec. 31, 2022
Equity [Abstract]
Comprehensive Income	15. COMPREHENSIVE INCOME The following tables detail the changes in the balances of each component of accumulated other comprehensive income for the affected periods: Unrealized Gains (1) Amortization of (1) Gain (Loss) on (1) Credit Risk Changes of Fair Value Option Liabilities (1) (2) Total Year Ended December 31, 2022: Beginning Balance $ 154 $ 4 $ (100) $ (1) $ 58 Other comprehensive income (loss) before reclassifications (211) — (85) — (296) Amounts reclassified from accumulated other comprehensive income (loss) (14) (1) — — (15) Net current period other comprehensive income (loss) (225) (1) (85) — (310) Balance at December 31, 2022 $ (71) $ 3 $ (184) $ (1) $ (253) Year ended December 31, 2021: Beginning Balance $ 166 $ 5 $ (92) $ — $ 79 Other comprehensive income before reclassifications (5) — (8) — (13) Amounts reclassified from accumulated other comprehensive income (7) (1) — (1) (9) Net current period other comprehensive income (loss) (12) (1) (8) (1) (21) Balance at December 31, 2021 $ 154 $ 4 $ (100) $ (1) $ 58 (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 Other Amount Reclassified from Accumulated Affected Line Item in the Year Ended December 31, 2022 2021 Unrealized Gains (Losses) on Available-for-Sale Securities (1) $ (17) $ (7) Net realized investment gains (losses) 3 (1) Provision for income taxes $ (14) $ (7) Net of tax and noncontrolling interest Amortization of Postretirement Benefit Prior service cost $ (1) $ (1) Other income Actuarial gains (losses) — — Other income (1) (1) Total before tax — — Provision for income taxes $ (1) $ (1) Net of tax and noncontrolling interest Credit Risk Changes of Fair Value Option Liabilities $ — $ (1) Credit risk changes of fair value option liabilities — — Provision for income taxes — (1) Net of tax and noncontrolling interest Total reclassifications for the period $ (15) $ (9) Net of tax and noncontrolling interest (1) Net unrealized investment gains (losses) on available for sale securities are included in Ambac's Consolidated Statements of Comprehensive Income as a component of Accumulated Other Comprehensive Income. Changes in these amounts include reclassification adjustments to exclude from "Other comprehensive income (loss)" those items that are included as part of "Net income" for a period that has been part of "Other comprehensive income (loss)" in earlier periods.

Net Income Per Share

Net Income Per Share	12 Months Ended
Net Income Per Share	Dec. 31, 2022
Earnings Per Share [Abstract]
Net Income Per Share	16. NET INCOME PER SHARE As of December 31, 2022, 44,973,757 shares of AFG's common stock (par value $0.01) and warrants entitling holders to acquire up to 4,877,617 shares of new common stock at an exercise price of $16.67 per share were issued and outstanding. Common shares outstanding decreased by 1,330,382, during the year ended December 31, 2022, primarily due to share repurchases partially offset by settlements of employee restricted and performance stock units. For the three years ended December 31, 2022, 2021 and 2020, —, 132 and 34 warrants were exercised, respectively, resulting in an issuance of —, 4 and 8 shares of common stock, respectively. Share Repurchases On March 29, 2022, AFG's Board of Directors approved a share repurchase program authorizing up to $20 in share repurchases, with an expiration date of March 31, 2024, which may be terminated at any time. As of December 31, 2022, AFG repurchased 1,605,316 shares for $14.2 with an average purchase price of $8.86 per share. On May 5, 2022, the Board of Directors authorized an additional $15 in share repurchase bringing the total unused authorized amount to $20.8. Warrant Repurchases On June 30, 2015, the Board of Directors of AFG authorized the establishment of a warrant repurchase program that permits the repurchase of up to $10 of warrants. On November 3, 2016, the Board of Directors of AFG authorized a $10 increase to the warrant repurchase program. The remaining aggregate authorization at December 31, 2022 was $12. For the years ended December 31, 2022 and 2021, AFG did not repurchase any warrants. 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 adjustment to redemption value of redeemable noncontrolling interests under ASC 480. The redemption value adjustment is further described in the Redeemable Noncontrolling Interests 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: Year ended December 31, 2022 2021 2020 Net income (loss) attributable to common stockholders $ 522 $ (17) $ (437) Adjustment to redemption value (ASC 480) 3 (12) — Numerator of basic and diluted EPS $ 525 $ (28) $ (437) Per Share: Basic 11.48 $ (0.61) $ (9.47) Diluted 11.31 $ (0.61) $ (9.47) 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 common shares used for basic net income per share to the diluted shares used for diluted net income per share: Year Ended December 31, 2022 2021 2020 Basic weighted average shares outstanding 45,719,906 46,535,001 46,147,062 Effect of potential dilutive shares (1) : Warrants — — — Stock options — — — Restricted stock units 144,194 — — Performance stock units (2) 550,730 — — Diluted weighted average shares outstanding 46,414,830 46,535,001 46,147,062 Anti-dilutive shares excluded from the above reconciliation Warrants 4,877,617 4,877,653 4,877,754 Stock options — — 16,121 Restricted stock units 177,119 475,333 302,145 Performance stock units (2) — 700,915 1,002,501 (1) For the years ended years ended December 31, 2021 and 2020, Ambac had a net loss and accordingly excluded all potentially dilutive securities from the determination of diluted loss per share as their impact was anti-dilutive. (2) Performance stock units are reflected based on the performance metrics through the balance sheet date. Vesting of these units is contingent upon meeting certain performance metrics. Although a portion of these performance metrics have been achieved as of the respective period end, it is possible that awards may no longer meet the metric at the end of the performance period.

Income Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	17. 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 Consolidated Pretax Income (Loss) U.S. and foreign components of pre-tax income (loss) were as follows: Year Ended December 31, 2022 2021 2020 U.S. $ 511 $ (32) $ (441) Foreign 13 34 1 Total $ 525 $ 2 $ (440) Provision (Benefit) for Income Taxes The components of the provision (benefit) for income taxes were as follows: Year Ended December 31, 2022 2021 2020 Current taxes U.S. state and local $ — $ 2 $ — Foreign 7 10 8 Total current taxes 6 12 8 Deferred taxes Foreign (4) 6 (10) Total deferred taxes $ (4) $ 6 $ (10) Provision for income taxes $ 2 $ 18 $ (3) The total effect of income taxes on net income and stockholders’ equity for the years ended December 31, 2022, 2021 and 2020 is as follows: Year Ended December 31, 2022 2021 2020 Total income taxes charged to net income $ 2 $ 18 $ (3) Income taxes charged (credited) to stockholders’ equity: Unrealized gains (losses) on investment securities, including foreign exchange (47) (3) 3 Change in retirement benefits — — — Credit Risk Changes to Fair Value Options — — — Valuation allowance to equity 41 1 (3) Total charged to stockholders’ equity: (6) (2) 1 Total effect of income taxes $ (4) $ 16 $ (1) Reconciliation of U.S. Federal Statutory Income Tax Rate to Actual Income Tax Rate The tax provisions in the accompanying Consolidated Statements of Total Comprehensive Loss reflect effective tax rates differing from prevailing Federal corporate income tax rates. The following is a reconciliation of these differences: Year Ended December 31, 2022 2021 2020 Tax on income (loss) at statutory rate $ 110 21 % $ — 21 % $ (92) 21 % Changes in expected tax resulting from: Tax-exempt interest (1) — % (2) (114) % (2) — % Foreign taxes 4 1 % 8 448 % 6 (1) % State Income Taxes (1) — % 14 794 % — — % Substantiation adjustment — — % — — % (29) 7 % Variable Interest Entities 25 5 % — — % — — % Valuation allowance (131) (25) % (4) (230) % 113 (26) % Other, net (4) (1) % 1 72 % 2 — % Tax expense on income (loss) $ 2 1 % $ 18 991 % $ (3) 1 % Unrecognized Tax Positions The Company had no material unrecognized tax benefits at December 31, 2021 and 2020. Deferred Income Taxes The tax effects of temporary differences that give rise to significant portions of the deferred tax liabilities and deferred tax assets at December 31, 2022 and 2021, are presented below: December 31, 2022 2021 Deferred tax liabilities: Insurance intangible $ 56 $ 67 Unearned premiums and credit fees 24 32 Investments — 14 Variable interest entities 4 15 Other 1 6 Total deferred tax liabilities 85 134 Deferred tax assets: Net operating loss carryforward 725 736 Interest expense carryforward 66 50 Investments 6 — Loss reserves 38 180 State capital loss carryforward 8 7 Debentures 15 7 Compensation 6 8 Other 4 4 Subtotal deferred tax assets 867 993 Valuation allowance 796 886 Total deferred tax assets 70 106 Net deferred tax liability $ 15 $ 28 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 the deferred tax operating assets and therefore maintains a full valuation allowance. The remaining net deferred tax liability of $15 is attributable to Ambac U.K. and is classified in other liabilities on the Consolidated Balance Sheet. NOL Usage & Investment Interest Carryforward Pursuant to a 2013 Closing Agreement between Ambac and the United States Internal Revenue Service ("IRS"), AAC could have to pay as much as $8 to the IRS in the year utilized should AAC utilize $2,142 of NOLs and Interest Expense Limitation available to it as of December 31, 2022.
Schedule of Net Operating Loss And Tax Credit Carryovers	Pursuant to a 2013 Closing Agreement between Ambac and the United States Internal Revenue Service ("IRS"), AAC could have to pay as much as $8 to the IRS in the year utilized should AAC utilize $2,142 of NOLs and Interest Expense Limitation available to it as of December 31, 2022.As of December 31, 2022, the Company has (i) $3,454 of NOLs, which if not utilized will begin expiring in 2030, and will fully expire in 2043, and (ii) $314 of interest expense tax deduction carryover, which has an indefinite carryforward period but is limited in any particular year based on certain provisions. Beginning in 2022, the Company is presenting these items separately in the deferred income tax table above with conforming display in 2021.

Employment Benefit Plans (Notes

Employment Benefit Plans (Notes)	12 Months Ended
Employment Benefit Plans (Notes)	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Compensation and Employee Benefit Plans [Text Block]	18. EMPLOYMENT BENEFIT PLANS Postretirement Health Care and Postemployment Benefits Ambac provides postretirement and postemployment/severance benefits, including health and life benefits for certain employees who meet predefined age and service requirements. None of the plans are currently funded. Postretirement and postemployment benefits expense, including severance benefits paid, were $2, $1 and $1 for the years ended December 31, 2022, 2021 and 2020, respectively. Effective August 1, 2005, new employees were not eligible for postretirement benefits. The current postretirement benefit requires retirees to purchase their own medical insurance policy with a portion of their premium being reimbursed by Ambac. The unfunded accumulated postretirement benefit obligation was $11 as of December 31, 2022. The assumed health care cost trend rates range from 5.5% in 2023, decreasing ratably to 4.5% in 2032. The following table sets forth projected benefit payments from Ambac’s postretirement plan over the next ten years for current retirees: 2023 $ — 2024 — 2025 — 2026 — 2027 1 Thereafter 3 Total $ 5 The discount rate used in determining the projected benefit obligations for the postretirement plan is selected by reference to a pension liability index with similar duration to that of the benefit plan. The rates used for the projected plan benefit obligations at the measurement date for December 31, 2022 and 2021, were 5.00% and 2.75%, respectively. Savings Incentive Plans As a result of the acquisitions of All Trans and Capacity Marine effective November 1, 2022, Ambac has multiple savings incentive plans. Substantially all US employees are covered by one of these plans. The Plan sponsored by AFG includes employer matching contributions equal to 100% of the employees’ contributions, up to 3% of such participants’ compensation, as defined in the plan, plus 50% of contributions up to an additional 2% of compensation, subject to limits set by the Internal Revenue Code. Xchange employees moved to this plan from a previous plan sponsored by Xchange during 2022. The Xchange sponsored plan included employer matching contributions equal to 4% of such participants' compensation, as defined in the plan. Employees of All Trans and Capacity Marine are included in a multiple employer plan that has discretionary contributions for which none were made during Ambac's ownership of these entities. The total cost of the savings incentive plans were $1, $1 and $1 for the years December 31, 2022, 2021 and 2020, respectively. Incentive Compensation - Stock Units and Cash Employees, directors and consultants of Ambac are eligible to participate in Ambac’s 2020 Incentive Plan, which is the successor plan to the 2013 Incentive Plan, subject to the discretion of the compensation committee of Ambac’s Board of Directors. There are 1,475,000 and 4,000,000 shares of Ambac's common stock authorized for awards under the 2020 Plan and 2013 Plan, respectively. Awards may also be made under the 2020 Plan with respect to the shares that remained available for grant under the 2013 Plan. In addition, shares subject to outstanding awards granted under the 2013 Plan that subsequently terminate by expiration or forfeiture, cancellation, or otherwise without the issuance of such shares become available for awards under the 2020 Plan. Of the total shares authorized for issuance pursuant to the 2020 Plan and 2013 Plan, the following are the number of shares available for future grant at December 31, 2022: • 74,907 shares when shares available for future grant are reduced by the maximum number of shares that could be issued pursuant to outstanding performance awards; and • 1,145,243 shares when shares available for future grant are reduced by the probable number of shares that could be issued pursuant to outstanding performance awards which are subject to change depending on actual performance. On June 24, 2021, the compensation committee of Ambac's Board of Directors adopted the Ambac Financial Group, Inc. Executive Stock Deferral Plan (the “Stock Deferral Plan”). Under the Stock Deferral Plan, certain executives of AFG and its subsidiaries who are designated by the compensation committee as eligible to participate in the Stock Deferral Plan may elect to defer the settlement of all or a portion of the RSU (as defined below) awards and PSU (as defined below) awards that are granted to the executives to a future date(s) selected by the executive. Deferred awards under the Stock Deferral Plan (and any related dividend equivalents) will continue to be paid in shares of common stock of AFG, which will be issued under the 2020 Plan, provided that any dividend equivalents credited on a participant’s deferred awards in respect of cash dividends paid by AFG will be paid to the participant in cash. The Stock Deferral Plan is not funded, and deferred awards under the Stock Deferral Plan are not segregated from the Company’s general assets. The amount of stock-based compensation expense and corresponding after-tax expense are as follows: Year Ended December 31, 2022 2021 2020 Restricted stock units 5 5 3 Performance awards 12 10 8 Total stock-based compensation $ 17 $ 14 $ 11 Total stock-based compensation (after-tax) $ 17 $ 14 $ 11 Restricted Stock Units (“RSUs”) RSUs can be awarded to certain employees for a portion of their STIP compensation, LTIP compensation, sign-on and special awards for exceptional performance. RSUs can also be awarded to consultants for meeting certain contractual performance goals. The LTIP, sign-on, consultant and special awards generally vest in equal installments over a two to three year period. Such vesting is expressly conditioned upon continued service with Ambac through the applicable vesting date, although vesting may be accelerated in certain circumstances under the awards, including for terminations due to death, disability, eligible retirement, or involuntary termination by Ambac other than for cause. As part of our director compensation program, prior to 2021 RSUs were awarded annually on or about April 30 of each year to directors and would vest on the last day of April of the following year. During 2021, the director compensation program was revised to provide for quarterly grants of RSUs that would vest one year from the grant date. These RSUs will not settle until the respective director’s termination from the board of directors or, if earlier, upon a change in control. All RSUs provide for accelerated vesting upon a change in control, death or disability or involuntary removal other than for cause (not including removal pursuant to a shareholder vote at a regularly scheduled annual meeting of shareholders). Upon termination (other than for cause), the unvested RSUs shall partially vest as of the date of such termination in an amount equal to the number of then outstanding unvested RSUs multiplied by a fraction, the numerator of which shall be the number of calendar days which have lapsed since the grant date and the denominator of which shall be the number of calendar days from the grant date until the next regularly scheduled quarterly grant date pursuant to Ambac’s director compensation program. As of December 31, 2022, 923,250 RSUs remained outstanding, of which (i) 538,163 units required future service as a condition to the delivery of the underlying shares of common stock and (ii) 385,087 units do not require future service and are deferred for future settlement. As of December 31, 2021, 837,070 RSUs remained outstanding, of which (i) 504,764 units required future service as a condition to the delivery of the underlying shares of common stock, and (ii) 332,306 units did not require future service and were deferred for future settlement. A summary of RSU activity for 2022 is as follows: Shares Weighted Average Grant Date Fair Value Per Share Outstanding at beginning of period 837,070 $ 17.82 Granted 352,141 $ 12.48 Delivered or returned to plan (1) (263,505) $ 17.13 Forfeited (2,456) $ 15.65 Outstanding at end of period 923,250 $ 15.94 (1) When restricted stock unit awards issued by Ambac become taxable compensation to employees, shares may be withheld to cover the employee’s withholding taxes. For the year ended December 31, 2022, Ambac withheld 97,871 shares from employees that settled restricted stock units to meet the required tax withholdings. Ambac’s closing share price on the grant date was used to estimate the fair value of the service condition based RSU on the grant date. The weighted average grant date fair value per share of RSUs granted during 2022, 2021 and 2020 was $12.48, $17.39 and $17.36, respectively. As of December 31, 2022, there was $4 of total unrecognized compensation costs related to unvested RSUs granted. These costs are expected to be recognized over a weighted average period of 1.6 years. The fair value for RSUs vested and delivered during the year ended December 31, 2022, 2021 and 2020 was $4, $4 and $4, respectively. Performance Stock Awards ("PSUs") PSUs are awarded to certain employees for a portion of their LTIP compensation and vest after 3 years from grant date. The actual number of shares payable at settlement is subject to performance metrics relative to AFG, Xchange, Everspan and AAC. Actual payout can range from 0% to 240% of the number of units granted. Under currently outstanding award agreements, performance will be evaluated as follows: • In regards to Xchange, for the 2021 and 2022 PSU awards, cumulative earnings before interest, taxes, depreciation and amortization over the vesting period. • In regards to Everspan, for the 2022 PSU awards, cumulative earnings before interest, taxes, depreciation and amortization over the vesting period. • In regards to AAC: (i) changes in AAC's assets relative to its insurance and financial obligations, which is intended to reward participants for increases in the relative value of AAC (2020 PSU awards only) and (ii) reductions in watch list and adversely classified credits, which is intended to reward participants for de-risking the financial guarantee insured portfolio. • Relative Total Shareholder Return; the modifier will cause the payout at the end of the performance period to be increased or decreased 10% for awards issued through 2021 and 20% for 2022 awards, if AFG's stock performance compared to a peer group is at or above the 75th percentile or at or below the 25th percentile, respectively . Pursuant to the LTIP award agreements if (i) a termination occurs by reason of disability, an involuntary termination by the Company other than for “cause,” or "retirement," the recipient would be entitled to receive the PSU award which would only be payable at the end of the relevant performance period and based on the satisfaction of the performance conditions related to such award at the time of termination and (ii) a termination occurred prior to the last day of the performance period by reason of death, the beneficiaries of the recipient would be entitled to receive the number of PSUs that the recipient would have been entitled to receive at a 100% overall payout multiple regardless of the outcome of any of the performance conditions. The current performance awards shall be settled within 75 days after the end of the performance period, including those with partial or accelerated vesting, subject to any deferrals made pursuant to the Stock Deferral Plan. A summary of PSU activity for 2022 is as follows: Shares Weighted Average Outstanding at beginning of period 722,056 $ 18.97 Granted (1) 529,285 13.44 Delivered (2) (422,620) 19.42 Forfeited (7,361) 16.93 Performance adjustment (3) 97,591 19.17 Outstanding at end of period 918,951 $ 15.67 (1) Represents performance share units at 100% of units granted for LTIP Awards. (2) Reflects the number of performance shares attributable to the performance goals attained over the completed performance period and for which service conditions have been met. When performance stock unit awards issued by Ambac become taxable compensation to employees, shares may be withheld to cover the employee’s withholding taxes. For the year ended December 31, 2022, Ambac purchased 157,377 of shares from employees that settled performance based restricted stock units to meet the required tax withholdings. (3) Represents the number of additional shares issued for awards granted in 2019 as a result of actual performance during the performance period.

Leases (Notes)

Leases (Notes)	12 Months Ended
Leases (Notes)	Dec. 31, 2022
Leases of Lessee Disclosure [Text Block]	19. LEASES Ambac is the lessee and lessor under certain lease agreements further described below. Lessee information Ambac is the lessee in operating leases for corporate offices, a data center, auto and equipment. Leases in effect at December 31, 2022, have remaining lease terms ranging from under 1 year to 7 years. Certain of these leases include automatic renewal or early termination provisions. Ambac does not include these provisions in the determination of its lease liabilities and right-of-use assets unless exercise is considered reasonably certain. Lease costs are included in operating expenses on the Consolidated Statement of Total Comprehensive Income (Loss). The components of lease costs, net of sub-lessor income, is as follows: Year Ended December 31, 2022 2021 Operating lease cost $ 4 $ 5 Short-term lease cost — — Variable lease cost — — Sublease income (1) (1) Total lease cost $ 4 $ 4 Ambac is required to make variable lease payments under certain leases which primarily relates to variable costs of the lessor, such as taxes, insurance, maintenance and electricity. Supplemental information related to leases is as follows: Year Ended December 31, 2022 2021 Cash paid for amounts included in the measurement of operating lease liabilities $ 5 $ 5 Right-of-use assets obtained in exchange for operating lease liabilities (non-cash) — — Supplemental balance sheet information related to leases is as follows: December 31, 2022 2021 Operating leases: Operating lease right of use assets $ 21 $ 23 Operating lease liabilities 25 28 Weighted average remaining lease term: Operating leases 6.8 years 7.7 years Weighted average discount rate: Operating leases 7.8 % 7.7 % Operating lease right of use assets and operating lease liabilities are included in Other assets and Other liabilities, respectively, on the consolidated balance sheet. Future undiscounted lease payments, gross of sublease receipts, to be made are as follows: As of December 31, 2022 Operating Leases 2023 $ 5 2024 5 2025 5 2026 4 2027 4 Thereafter 9 Total lease payments 32 Less: imputed interest (7) Total $ 25 Lessor information Ambac is the lessor in one operating sublease of corporate office space which has a remaining term of 7.0 years. There are no extension or termination provisions. Future undiscounted lease payments to be received are as follows: As of December 31, 2022 Operating Leases 2023 $ 1 2024 1 2025 1 2026 1 2027 1 Thereafter 3 Total lease receipts $ 9

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended	12 Months Ended
Commitments and Contingencies	Jun. 30, 2021	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	20. COMMITMENTS AND CONTINGENCIES	20. COMMITMENTS AND CONTINGENCIES Litigation Against Ambac - Pending Cases Monterey Bay Military Housing, LLC, et al. v. Ambac Assurance Corporation, et al. (United States District Court, Southern District of New York, Case No. 1:19-cv-09193-PGG, transferred on October 4, 2019 from the United States District Court, Northern District of California, San Jose Division, Case No. 17-cv-04992-BLF, filed August 28, 2017). Plaintiffs, the corporate developers of various military housing projects, filed an amended complaint on October 27, 2017 against AAC, a former employee of AAC, and certain unaffiliated persons and entities, asserting claims for (i) violation of 18 U.S.C §§ 1962(c) and 1962(d) (civil Racketeer Influenced and Corrupt Organizations Act (“RICO”) and conspiracy to commit civil RICO), (ii) breach of fiduciary duty, (iii) aiding and abetting breach of fiduciary duty, (iv) fraudulent misrepresentation, (v) fraudulent concealment and (vi) conspiracy to commit fraud. The claims relate to bonds and debt certificates (insured by AAC) that were issued to finance the renovation and construction of housing at certain military bases. Plaintiffs allege that defendants secretly conspired to overcharge plaintiffs for the financing of the projects and directed the excess profits to themselves. Plaintiffs allege defendants generated these excess profits by supposedly charging inflated interest rates, manipulating “shadow ratings,” charging unnecessary fees, and hiding evidence of their alleged wrongdoing. Plaintiffs seek, among other things, compensatory damages, disgorgement of profits and fees, punitive damages, trebled damages and attorneys’ fees. AAC and the other defendants filed motions to dismiss the amended complaint on November 13, 2017. On July 17, 2018, the court granted AAC’s and the other defendants’ motion to dismiss the first amended complaint without prejudice. On December 17, 2018, Plaintiffs filed a second amended complaint. On February 15, 2019, AAC and the other defendants filed a motion to dismiss the second amended complaint. On September 26, 2019, the court issued a decision denying defendants’ motion to dismiss and sua sponte reconsidering its previous denial of defendants’ motion to transfer venue to the Southern District of New York (“SDNY”). On October 10, 2019, after the case was transferred to the SDNY, the defendants filed motions to vacate or reconsider the decision by the Northern District of California on the defendants’ motion to dismiss. On March 31, 2021, the court granted defendants’ motions for reconsideration and, upon reconsideration, dismissed the claims against AAC and its former employee for breach of fiduciary duty and for aiding and abetting breach of AAC’s or its former employee’s fiduciary duty; dismissed two plaintiffs’ RICO claims against AAC and its former employee; and in all other respects denied defendants’ motions. Defendants served answers to the second amended complaint on April 21, 2021, asserting several affirmative defenses, including a defense for unclean hands focused on the plaintiffs’ failure to maintain the project properties and falsification of maintenance records. On May 24, 2021, plaintiffs moved to strike defendants’ unclean hands defenses. On September 14, 2021, Magistrate Judge Sarah L. Cave, to whom plaintiffs’ motion to strike was referred for a Report and Recommendation, issued an opinion and order denying plaintiffs’ motion. On April 6, 2022, certain co-defendants filed a motion to sever the plaintiffs’ claims and to dismiss all claims except for claims asserted by the Monterey Bay plaintiffs. In re National Collegiate Student Loan Trusts Litigation (Delaware Court of Chancery, Consolidated C.A. No. 12111, filed November 1, 2019). On November 1, 2019, AAC became aware of a new declaratory judgment action filed by certain residual equity interest holders (“NC Owners” or “Plaintiffs”) in fourteen National Collegiate Student Loan Trusts (the “Trusts”) against Wilmington Trust Company, the Owner Trustee for the Trusts; U.S. Bank National Association, the Indenture Trustee; GSS Data Services, Inc., the Administrator; and AAC. Through this action, Plaintiffs seek a number of judicial determinations. On January 21, 2020, the presiding Vice Chancellor entered an order consolidating the action with previously filed litigation relating to the Trusts. On February 13, 2020, AAC, the Owner Trustee, the Indenture Trustee, and other parties filed declaratory judgment counterclaims. Several parties, including Plaintiffs and AAC, filed motions for judgment on the pleadings in support of their requested judicial determinations. On August 27, 2020, the Vice Chancellor issued an opinion addressing all of the pending motions for judgment on the pleadings, which granted certain of the parties’ requested judicial determinations and denied others. He deferred judgment on still other declarations pending further factual development. The Vice Chancellor has entered a series of stays to facilitate good-faith settlement discussions, the most recent of which was entered on January 27, 2023, and stays the matter through February 28, 2023. Financial Oversight and Management Board for Puerto Rico, et al. v. Autonomy Master Fund Limited, et al. (United States District Court, District of Puerto Rico, No. 19-ap-00291, filed May 2, 2019). On May 2, 2019, the Financial Oversight and Management Board for Puerto Rico (the “Oversight Board”), together with the Official Committee of Unsecured Creditors for the Commonwealth (the “Committee”), filed an adversary proceeding against certain parties that filed proofs of claim on account of general obligation bonds issued by the Commonwealth of Puerto Rico, including AAC. The complaint seeks declarations that the general obligation bonds are unsecured obligations and, in the alternative, seeks to avoid any security interests that holders of such bonds may have. On June 12, 2019, a group of general obligation bondholders moved to dismiss the complaint. On June 13, 2019, at the request of the Plaintiffs, the District Court stayed the case until September 1, 2019 as to all defendants; on July 24, 2019, the District Court referred this matter to mediation and ordered it stayed during the pendency of such mediation. AAC filed a statement of position and reservation of rights on February 5, 2020; certain other defendants filed motions to dismiss on this same date. On February 9, 2020, the Oversight Board announced that it intended to file, and to seek to confirm, an amended plan of adjustment (the “Commonwealth Plan”). On March 10, 2020, the District Court ordered that this case remain stayed while the Oversight Board attempted to confirm the Commonwealth Plan. The January 18, 2022 confirmation of the Commonwealth Plan, which is currently being appealed (as described below), resolved this litigation. On May 9, 2022, the District Court dismissed this case. 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 (as defined below), 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, discussed below). The October 12, 2022 confirmation of the PRHTA POA (as defined below), which is currently being appealed (as described below), resolved this litigation. AAC expects this case will be dismissed pursuant to PRHTA POA. Financial Oversight and Management Board for Puerto Rico v. Ambac Assurance Corp., et al. (United States District Court, District of Puerto Rico, No. 20-ap-00003, filed Jan. 16, 2020). On January 16, 2020, the Oversight Board filed an adversary proceeding against monoline insurers insuring PRIFA (as defined below) bonds and the PRIFA bond trustee, all of which defendants filed proofs of claim against the Commonwealth relating to PRIFA bonds. The complaint seeks to disallow defendants’ proofs of claim against the Commonwealth in their entirety, including for lack of secured status. On February 27, 2020, defendants filed motions to dismiss. On March 10, 2020, the District Court stayed the motions to dismiss and authorized the Oversight Board to move for summary judgment, which motion defendants opposed. On May 5, 2021, Assured Guaranty Corp. and Assured Guaranty Municipal Corp. (“Assured”) and National Public Finance Guarantee Corporation (“National”) announced an agreement with the Oversight Board with respect to the PRHTA/PRCCDA Settlement (as defined below). On July 14, 2021, AAC and Financial Guaranty Insurance Company (“FGIC”) reached an agreement in principle with the Oversight Board with respect to the PRIFA Settlement (as defined below). On August 2, 2021, the Oversight Board, AAC, FGIC, and the PRIFA bond trustee jointly moved to stay this case as a result of the PRIFA Settlement and AAC’s joinder to the PRHTA/PRCCDA Settlement and the GO/PBA Settlement (as defined below). On August 3, 2021, the District Court ordered that this case be stayed. The January 18, 2022 confirmation of the Commonwealth Plan, which is currently being appealed (as described below), resolved this litigation. On September 30, 2022, the District Court entered an order closing this adversary proceeding. Financial Oversight and Management Board for Puerto Rico v. Ambac Assurance Corp., et al. (United States District Court, District of Puerto Rico, No. 20-ap-00004, filed Jan. 16, 2020). On January 16, 2020, the Oversight Board filed an adversary proceeding against monoline insurers insuring PRCCDA (as defined below) bonds and the PRCCDA bond trustee, all of which defendants filed proofs of claim against the Commonwealth relating to PRCCDA bonds. The complaint seeks to disallow defendants’ proofs of claim against the Commonwealth in their entirety, including for lack of secured status. On February 27, 2020, defendants filed motions to dismiss. On March 10, 2020, the District Court stayed the motions to dismiss and authorized the Oversight Board to move for summary judgment, which motion defendants opposed. On May 5, 2021, Assured and National announced an agreement with the Oversight Board with respect to the PRHTA/PRCCDA Settlement. On July 14, 2021, AAC and FGIC reached an agreement in principle with the Oversight Board with respect to the PRIFA Settlement. On August 2, 2021, the Oversight Board, AAC, FGIC, and the PRCCDA bond trustee jointly moved to stay this case as a result of the PRIFA Settlement and AAC’s joinder to the PRHTA/PRCCDA Settlement and the GO/PBA Settlement. On August 3, 2021, the District Court ordered that this case be stayed. The January 18, 2022 confirmation of the Commonwealth Plan, which is currently being appealed (as described below), resolved this litigation. On September 30, 2022, the Court entered an order closing this adversary proceeding. Financial Oversight and Management Board for Puerto Rico v. Ambac Assurance Corp., et al. (United States District Court, District of Puerto Rico, No. 20-ap-00005, filed Jan. 16, 2020). On January 16, 2020, the Oversight Board filed an adversary proceeding against monoline insurers insuring PRHTA bonds, certain PRHTA bondholders, and the PRHTA fiscal agent for bondholders, all of which defendants filed proofs of claim against the Commonwealth relating to PRHTA bonds. The complaint seeks to disallow defendants’ proofs of claim against the Commonwealth in their entirety, including for lack of secured status. On February 27, 2020, defendants filed motions to dismiss. On March 10, 2020, the District Court stayed the motions to dismiss and authorized the Oversight Board to move for summary judgment, which motion defendants opposed. On May 5, 2021, Assured and National announced an agreement with the Oversight Board with respect to the PRHTA/PRCCDA Settlement. On July 14, 2021, AAC and FGIC reached an agreement in principle with the Oversight Board with respect to the PRIFA Settlement. On August 2, 2021, the Oversight Board, AAC, FGIC, and the PRHTA fiscal agent jointly moved to stay this case as a result of the PRIFA Settlement and AAC’s joinder to the PRHTA/PRCCDA Settlement and the GO/PBA Settlement. On August 3, 2021, the District Court ordered that this case be stayed. The January 18, 2022 confirmation of the Commonwealth Plan, which is currently being appealed (as described below), resolved this litigation. On September 30, 2022, the District Court entered an order closing this adversary proceeding. Financial Oversight and Management Board for Puerto Rico v. Ambac Assurance Corp., et al. (United States District Court, District of Puerto Rico, No. 20-ap-00007, filed Jan. 16, 2020). On January 16, 2020, the Oversight Board and the Committee filed an adversary proceeding against monoline insurers insuring bonds issued by PRHTA, certain PRHTA bondholders, and the PRHTA fiscal agent for bondholders, all of which defendants filed proofs of claim against PRHTA relating to PRHTA bonds. The complaint seeks to disallow portions of defendants’ proofs of claim against PRHTA, including for lack of secured status. On March 10, 2020, the District Court stayed this case. On May 5, 2021, Assured and National announced an agreement with the Oversight Board with respect to the PRHTA/PRCCDA Settlement. On July 14, 2021, AAC and FGIC reached an agreement in principle with the Oversight Board with respect to the PRIFA Settlement. On August 2, 2021, the Oversight Board, AAC, FGIC, and the PRHTA fiscal agent jointly moved to stay this case as a result of the PRIFA Settlement and AAC’s joinder to the PRHTA/PRCCDA Settlement and the GO/PBA Settlement. On August 3, 2021, the District Court ordered that this case be stayed. On April 14, 2022, the Oversight Board filed a notice that this case has not been resolved by the Commonwealth Plan and should remain pending. The October 12, 2022 confirmation of the PRHTA POA, which is currently being appealed (as described below), resolved this litigation. On September 30, 2022, the Court entered an order closing this adversary proceeding. Litigation Against Ambac - General AAC’s estimates of projected losses for RMBS transactions consider, among other things, the RMBS transactions’ payment waterfall structure, including the application of interest and principal payments and recoveries, and depend in part on our interpretations of contracts and other bases of our legal rights. From time to time, bond trustees and other transaction participants have employed different contractual interpretations and have commenced, or threatened to commence, litigation to resolve these differences. It is not possible to predict whether additional disputes will arise, nor the outcomes of any potential litigation. It is possible that there could be unfavorable outcomes in this or other disputes or proceedings and that our interpretations may prove to be incorrect, which could lead to changes to our estimate of loss reserves. AAC has periodically received various regulatory inquiries and requests for information with respect to investigations and inquiries that such regulators are conducting. AAC has complied with all such inquiries and requests for information. The Company is involved from time to time in various routine legal proceedings, including proceedings related to litigation with present or former employees. Although such litigation routine and incidental to the conduct of its business, such litigation can potentially result in large monetary awards when a civil jury is allowed to determine compensatory and/or punitive damages. Everspan may be subject to disputes with policyholders regarding the scope and extent of coverage offered under Everspan's policies; be required to defend claimants in suits against its policyholders for covered liability claims; or enter into commercial disputes with its reinsurers, MGA/Us or third party claims administrators regarding their respective contractual obligations and rights. Under some circumstances, the results of such disputes or suits may lead to liabilities beyond those which are anticipated or reserved. From time to time, Ambac is subject to allegations concerning its corporate governance that may lead to litigation, including derivative litigation, and while the monetary impacts may not be material, the matters may distract management and the Board of Directors from their principal focus on Ambac's business, strategy and objectives. It is not reasonably possible to predict whether additional suits will be filed or whether additional inquiries or requests for information will be made, and it is also not possible to predict the outcome of litigation, inquiries or requests for information. It is possible that there could be unfavorable outcomes in these or other proceedings. Legal accruals for litigation against the Company in which a loss is probable and reasonably estimable are not material to the operating results or financial position of the Company, nor is it possible to predict a range of loss in excess of the accrued amounts. For all other litigation matters the Company is defending, management is unable to make a meaningful estimate of the amount or range of loss that could result from unfavorable outcomes. Under some circumstances, adverse results in any such proceedings could be material to our business, operations, financial position, profitability or cash flows. The Company believes that it has substantial defenses to the claims above and, to the extent that these actions proceed, the Company intends to defend itself vigorously; however, the Company is not able to predict the outcomes of these actions. Litigation Filed or Joined by Ambac In the ordinary course of their businesses, certain of Ambac’s subsidiaries assert claims in legal proceedings against third parties to recover losses already paid and/or mitigate future losses. The amounts recovered and/or losses avoided which may result from these proceedings is uncertain, although recoveries and/or losses avoided in any one or more of these proceedings during any quarter or fiscal year could be material to Ambac’s results of operations in that quarter or fiscal year. Puerto Rico On January 18, 2022, the United States District Court for the District of Puerto Rico (the “District Court”) entered an order confirming a plan of adjustment for the Commonwealth of Puerto Rico (the “Commonwealth Plan”). On January 20, 2022, the District Court entered orders approving a Qualifying Modification (the “PRIFA QM”) for the Puerto Rico Infrastructure Finance Authority (“PRIFA”) and a Qualifying Modification (the “PRCCDA QM”) for the Puerto Rico Convention Center District Authority (“PRCCDA”). On October 12, 2022, the District Court entered an order confirming a plan of adjustment (the “PRHTA POA”) for the Puerto Rico Highways and Transportation Authority (the “PRHTA”). These two plans of adjustment and two qualifying modifications incorporated settlements reached between AAC, the Oversight Board, and certain other parties related to each of AAC’s Puerto Rico-related exposures, which included agreements with respect to the treatment of general obligation and Puerto Rico Public Buildings Authority (“PBA”) bonds (the “GO/PBA Settlement”), PRHTA and PRCCDA bonds (the “PRHTA/PRCCDA Settlement”), and PRIFA bonds (the “PRIFA Settlement”). By incorporating these settlements, the Commonwealth Plan, PRIFA QM, PRCCDA QM, and PRHTA POA resolved the majority of AAC’s outstanding Puerto Rico-related litigation. The confirmation orders for both the Commonwealth Plan and the PRHTA POA have been appealed; if either confirmation order is reversed on appeal, the litigations that have been resolved by that confirmation order may be affected. The status of those appeals is discussed immediately below, followed by a discussion of AAC’s additional remaining outstanding Puerto Rico-related litigation. 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”). Teachers’ Unions : On April 26, 2022, the First Circuit rejected the Teachers’ Unions’ challenges to the Commonwealth Plan and affirmed the confirmation order; on May 10, 2022, the Teachers’ Unions petitioned for rehearing en banc . On May 13, 2022, the First Circuit denied the Teachers’ Unions’ petition for rehearing en banc . On August 9, 2022, the Teachers’ Unions filed a petition for a writ of certiorari seeking Supreme Court review of the First Circuit’s decision affirming the confirmation order; the Supreme Court denied the Teachers’ Unions’ petition on November 21, 2022. Oversight Board : On July 18, 2022, the First Circuit rejected the Oversight Board’s challenges to, and affirmed, the confirmation order. The Oversight Board filed a petition for a writ of certiorari seeking Supreme Court review of the First Circuit’s decision in its appeal of the confirmation order on October 17, 2022; the Supreme Court denied the petition on February 21, 2023. Individual creditors : On October 27, 2022, the First Circuit entered an order dismissing the individual creditors’ confirmation appeal. Credit Unions : On November 23, 2022, the First Circuit entered an order dismissing the Credit Unions’ appeal. Suiza : The Suiza appeal remains pending before the First Circuit. 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”) filed a notice of appeal with respect to, and a motion to stay, the PRHTA POA confirmation order. On October 28, 2022, a number of parties—including AAC—filed an opposition to the stay motion, requesting, in the alternative, that the appealing parties seeking a stay be required to post supersedeas bonds pending appeal. On November 15, 2022, the District Court entered an order denying the Vazquez-Velazquez Group’s motion for a stay pending appeal. On November 21, 2022, the Vazquez-Velazquez Group filed a motion in the First Circuit for a stay pending appeal. On November 29, 2022, a number of parties—including the Oversight Board and AAC—filed oppositions to the Vazquez-Velazquez Group’s stay motion. The Vazquez-Velazquez Group filed a brief on the same day requesting to withdraw their stay motion. The First Circuit granted the request to withdraw the stay motion on November 30, 2022. The Vazquez-Velazquez Group filed its opening brief in the First Circuit on February 15, 2023. Assured Guaranty Corp., Assured Guaranty Municipal Corp., and Ambac Assurance Corporation v. Alejandro Garcia Padilla, et al. (United States District Court, District of Puerto Rico No. 3:16-cv-01037, filed January 7, 2016). On January 7, 2016, AAC, along with co-plaintiffs Assured, filed a complaint for declaratory and injunctive relief to protect its rights against the illegal clawback of certain revenue by the Commonwealth of Puerto Rico. Defendants moved to dismiss on January 29, 2016. On October 4, 2016, the court denied the Defendants’ motions to dismiss. On October 14, 2016, Defendants filed a Notice of Automatic Stay, asserting that Plaintiffs’ claims have been rendered moot and further asserting that the case was automatically stayed under section 405 of the Puerto Rico Oversight, Management and Economic Stability Act ("PROMESA"). On May 3, 2017, the Oversight Board filed a petition to adjust the Commonwealth’s debts under Title III of PROMESA, resulting in an automatic stay of litigation against the Commonwealth. On May 17, 2017, the court issued an order staying this case until further order of the court. AAC expects this case will be dismissed given the settlements reached between AAC and the Oversight Board. Ambac Assurance Corporation v. Puerto Rico Highways and Transportation Authority (United States District Court, District of Puerto Rico, No. 16-cv-1893, filed May 10, 2016). AAC filed a complaint against the PRHTA on May 10, 2016, alleging breach of fiduciary duty and breach of contract in connection with PRHTA’s extension of an existing toll road concession agreement. The complaint alleges that it was inappropriate for PRHTA to enter into the extension agreement in its current state of financial distress because PRHTA has no control over, and is unlikely to receive, the proceeds of the transaction. AAC also filed related motions seeking the appointment of a provisional receiver for PRHTA and expedited discovery. On May 21, 2017, the Oversight Board filed a petition to adjust PRHTA’s debts under Title III of PROMESA, resulting in an automatic stay of litigation against PRHTA. On May 24, 2017, the court issued an order staying this case until further order of the court. The settlements reached between AAC and the Oversight Board resolved this litigation, and the January 20, 2022 PRIFA QM provided for dismissal of this case. AAC expects this case will be dismissed pursuant to the PRIFA QM. Ambac Assurance Corporation v. Puerto Rico, et al. (United States District Court, District of Puerto Rico, No. 17-1567, filed May 2, 2017). On May 2, 2017, AAC filed a complaint seeking a declaration that the Commonwealth’s Fiscal and Economic Growth Plan (the “FEGP”) and a statute called the “Fiscal Plan Compliance Law” are unconstitutional and unlawful because they violate the Contracts, Takings, and Due Process Clauses of the U.S. Constitution, are preempted by PROMESA, and are unlawful transfers of property from COFINA to the Commonwealth in violation of PROMESA. On May 3, 2017, a petition under Title III of PROMESA was filed on behalf of the Commonwealth of Puerto Rico, and on May 5, 2017, a petition under Title III of PROMESA was filed on behalf of COFINA, resulting in an automatic stay of litigation against COFINA. On May 17, 2017, the court issued an order staying this case until further order of the court. On August 2, 2021, the Oversight Board, AAC, FGIC, and the PRCCDA bond trustee jointly moved to stay this case as a result of the PRIFA Settlement and AAC's joinder to the PRHTA/PRCCDA Settlement and the GO/PBA Settlement. On August 3, 2021, the District Court ordered that this case be stayed. The settlements reached between AAC and the Oversight Board resolved this litigation, and the January 20, 2022 PRIFA QM provided for dismissal of this case. On January 24, 2023, the court dismissed this case. Ambac Assurance Corporation v. Puerto Rico, et al. (United States District Court, District of Puerto Rico, No. 17-1568, filed May 2, 2017). On May 2, 2017, AAC filed a complaint alleging that various moratorium laws and executive orders enacted by the Commonwealth to claw back funds from PRIFA, PRHTA, and PRCCDA bonds violate the Contracts, Takings, and Due Process Clauses of the U.S. Constitution, are preempted by PROMESA, and unlawfully transfer PRHTA, PRCCDA, and PRIFA property to the Commonwealth. On May 3, 2017, a petition under Title III of PROMESA was filed on behalf of the Commonwealth of Puerto Rico and on May 21, 2017, a petition under Title III of PROMESA was filed on behalf of PRHTA, resulting in an automatic stay of litigation against the Commonwealth and PRHTA (respectively). On May 17, 2017, the court issued an order staying this case until further order of the court. On August 2, 2021, the Oversight Board, AAC, FGIC, and the PRCCDA bond trustee jointly moved to stay this case as a result of the PRIFA Settlement and AAC's joinder to the PRHTA/PRCCDA Settlement and the GO/PBA Settlement. On August 3, 2021, the District Court ordered that this case be further stayed. The settlements reached between AAC and the Oversight Board resolved this litigation, and the January 20, 2022 PRIFA QM provided for dismissal of this case. On February 1, 2023, the court dismissed this case. Ambac Assurance Corporation v. Bank of New York Mellon (United States District Court, Southern District of New York, No. 1:17-cv-03804, filed May 2, 2017). On May 2, 2017, AAC filed a complaint in New York State Supreme Court, New York County, against the trustee for the COFINA bonds, Bank of New York Mellon (“BNY”), alleging breach of fiduciary, contractual, and other duties for failing to adequately and appropriately protect the holders of certain AAC-insured senior COFINA bonds. On May 19, 2017, BNY filed a notice of removal of this action from New York state court to the United States District Court for the Southern District of New York. On May 30, 2017, the United States District Court for the District of Puerto Rico entered an order in an adversary proceeding brought by BNY (No. 1:17-ap-00133) staying this litigation pending further order of the court. The COFINA Plan became effective on February 12, 2019, and, pursuant to the District Court’s confirmation order, this litigation was permitted to continue, with AAC’s claims against BNYM being limited to those for gross negligence, willful misconduct and intentional fraud. On November 17, 2021, the District Court denied as moot BNY's motion to transfer venue to the District of Puerto Rico and continued the stay of the action. On July 6, 2022, the District Court granted AAC’s motion to lift the stay and for leave to file a Second Amended Complaint (“SAC”). AAC filed its SAC on July 10, 2022, and on July 25, 2022, BNY moved to dismiss the SAC. On September 23, 2022, Ambac filed its opposition to BNY’s motion to dismiss, and on October 24, 2022, BNY filed its reply in support of its motion to dismiss. Oral argument has been requested but not yet scheduled. Financial Oversight and Management Board for Puerto Rico v. Public Buildings Authority (United States District Court, District of Puerto Rico, No. 1:18-ap-00149, filed December 21, 2018). On December 21, 2018, the Oversight Board, together with the Committee, as Plaintiffs, filed a complaint against the PBA seeking declaratory judgment that the leases between PBA and its lessees—many of whom are agencies and instrumentalities of the Commonwealth—are “disguised financings,” not true leases, and therefore should not be afforded administrative expense priority under the Bankruptcy Code. On March 12, 2019, AAC and other interested parties were permitted to intervene in order to argue that the PBA leases are valid leases and are entitled to administrative expense treatment under the Bankruptcy Code. On March 10, 2020, the District Court ordered that this case be stayed while the Oversight Board attempted to confirm the Commonwealth Plan. The January 18, 2022 confirmation of the Commonwealth Plan, which is currently being appealed, resolved this litigation. AAC expects this case will be dismissed pursuant to the Commonwealth Plan. In re Financial Oversight and Management Board for Puerto Rico (United States District Court, District of Puerto Rico, No. 1:17-bk-03283), Omnibus Objection of (I) Financial Oversight and Management Board, Acting Through its Special Claims Committee, and (II) Official Committee of Unsecured

SEC Schedule, Article 12-04, Co

SEC Schedule, Article 12-04, Condensed Financial Information of Registrant	12 Months Ended
	Dec. 31, 2022
Condensed Financial Information Disclosure [Abstract]
Condensed Financial Information of Parent Company Only Disclosure	AMBAC FINANCIAL GROUP, INC. AND SUBSIDIARIES Condensed Financial Information Of Registrant (Parent Company Only) Condensed Balance Sheets ($ in millions, except share data) December 31, 2022 2021 Assets: Fixed maturity securities, at fair value (amortized cost of $13 and $130) $ 12 $ 119 Short-term investments, at fair value (amortized cost of $175 and $124) 175 124 Other investments 16 11 Total investments (net of allowance for credit losses of $0 and $3) 203 254 Cash 3 1 Investment in subsidiaries 1,029 769 Investment income due and accrued 1 1 Other assets 19 17 Total assets $ 1,255 $ 1,041 Liabilities and Stockholders' Equity: Liabilities: Current taxes $ 1 $ 1 Accounts payable and other liabilities 3 2 Total liabilities 3 3 Stockholders’ equity: Preferred stock, par value $0.01 per share; 20,000,000 shares authorized shares; issued and outstanding shares—none — — Common stock, par value $0.01 per share; 130,000,000 shares authorized; issued shares: 46,658,990 and 46,477,068 — — Additional paid-in capital 274 257 Accumulated other comprehensive income (loss) (253) 58 Retained earnings 1,245 726 Treasury stock, shares at cost: 1,685,233 and 172,929 (15) (3) Total Ambac Financial Group, Inc. stockholders’ equity 1,252 1,038 Total liabilities and stockholders’ equity $ 1,255 $ 1,041 The condensed financial statements should be read in conjunction with the consolidated financial statements and notes thereto and the following notes. See the Report of Independent Registered Public Accounting Firm. SCHEDULE II AMBAC FINANCIAL GROUP, INC. AND SUBSIDIARIES Condensed Financial Information Of Registrant (Parent Company Only) Condensed Statement of Comprehensive Income ($ in millions) Year Ended December 31, 2022 2021 2020 Revenues: Investment income $ 10 $ 10 $ 13 Other income — — — Net gains on derivative contracts 1 — — Net investment gains (losses), including impairments (14) (5) (1) Total revenues (2) 5 12 Expenses: General and administrative expenses 17 19 19 Total expenses 17 19 19 Income (loss) before income taxes and equity in undistributed net gain (loss) of subsidiaries (20) (14) (7) Federal income tax provision (benefit) — 2 — Income (loss) before net income (loss) of subsidiaries (19) (16) (7) Net gain (loss) of subsidiaries 542 (1) (430) Net income (loss) $ 522 $ (17) $ (437) Other comprehensive income (loss), after tax: Net income (loss) $ 522 $ (17) $ (437) Unrealized gains (losses) on securities, net of income tax provision (benefit) of $(6), $(2) and $1 (225) (12) 15 Gains (losses) on foreign currency translation, net of income tax provision (benefit) of $—, $— and $— (85) (8) 23 Credit risk changes of fair value option liabilities, net of income tax provision (benefit) of $—, $— and $— — (1) 1 Changes to postretirement benefit, net of income tax provision (benefit) of $—, $— and $— (1) (1) (3) Total other comprehensive income (loss) (310) (21) 37 Total comprehensive income (loss) attributable to Ambac Financial Group, Inc. $ 212 $ (38) $ (400) The condensed financial statements should be read in conjunction with the consolidated financial statements and notes thereto and the following notes. See the Report of Independent Registered Public Accounting Firm. SCHEDULE II AMBAC FINANCIAL GROUP, INC. AND SUBSIDIARIES Condensed Financial Information Of Registrant (Parent Company Only) Condensed Statement of Stockholders' Equity ($ in millions) Total Retained Earnings Accumulated Other Comprehensive Income (Loss) Preferred Stock Common Stock Additional Paid-in Capital Common Stock Held in Treasury, at Cost Balance at January 1, 2020 $ 1,477 $ 1,203 $ 42 $ — $ — $ 232 $ — Total comprehensive income (loss) (400) (437) 37 — — — — Adjustment to initially apply ASU 2016-13 (4) (4) — — — — — Stock-based compensation 11 — — — — 11 — Cost of shares (acquired) issued under equity plan (3) (2) — — — — (1) Balance at December 31, 2020 1,080 759 79 — — 242 (1) Total comprehensive income (loss) (38) (17) (21) — — — — Stock-based compensation 14 — — — — 14 — Cost of shares (acquired) issued under equity plan (6) (4) — — — — (2) Changes to redeemable noncontrolling interest (12) (12) — — — — — Balance at December 31, 2021 1,038 726 58 — — 257 (3) Total comprehensive income (loss) 211 521 (310) — — — — Stock-based compensation 17 — — — — 17 — Cost of shares (acquired) issued under equity plan (4) (5) — — — — 2 Cost of shares repurchased (14) — — — — — (14) Change in redeemable noncontrolling interest 3 3 — — — — — Purchase of Ambac Assurance auction market preferred shares 1 1 — — — — — Balance at December 31, 2022 $ 1,252 $ 1,245 $ (253) $ — $ — $ 274 $ (15) The condensed financial statements should be read in conjunction with the consolidated financial statements and notes thereto and the following notes. See the Report of Independent Registered Public Accounting Firm. SCHEDULE II AMBAC FINANCIAL GROUP, INC. AND SUBSIDIARIES Condensed Financial Information Of Registrant (Parent Company Only) Condensed Statements of Cash Flow ($ in millions) Year Ended December 31, 2022 2021 2020 Cash flows from operating activities: Net income (loss) $ 522 $ (17) $ (437) Adjustments to reconcile net income loss to net cash used in operating activities: Net (income) loss of subsidiaries (542) 1 423 Amortization of bond premium and discount (7) (9) (6) Net investment gains (losses), including impairments 14 5 1 Increase (decrease) in current income taxes payable (1) 1 30 Share-based compensation 12 14 11 (Increase) decrease in other assets and liabilities 41 (5) (1) Distributions received from majority owned subsidiary 6 6 — Other, net 1 (6) (10) Net cash provided by (used in) operating activities 46 (10) 11 Cash flows from investing activities: Proceeds from sales and matured bonds 68 33 46 Purchases of bonds (1) (34) (45) Change in short-term investments (51) 105 89 Change in other investments (4) (8) — Acquisitions, net of cash acquired — — (74) Net cash provided by (used in) investing activities 12 95 16 Cash flows from financing activities: Capital contribution to subsidiaries (42) (92) (29) Cost of shares acquired (14) — — Net cash (used in) financing activities (57) (92) (29) Net cash flow 1 (6) (2) Cash at beginning of period 1 7 9 Cash at end of period $ 3 $ 1 $ 7 Supplemental disclosure of cash flow information: Cash paid during the period for: Income taxes $ — $ — $ — The condensed financial statements should be read in conjunction with the consolidated financial statements and notes thereto and the following notes.

Reorganizations (Policies)

Reorganizations (Policies)	12 Months Ended
Reorganizations (Policies)	Dec. 31, 2022
Reorganizations [Abstract]
Strategies to Enhance Shareholder Vakye	Strategies to Enhance Shareholder Value The Company's primary goal is to maximize long-term shareholder value through the execution of key strategies for its (i) Specialty Property and Casualty Insurance and Insurance Distribution businesses and (ii) Legacy Financial Guarantee Insurance. 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.
Surplus Note Exchanges and Repurchases	Surplus Note Exchanges and Repurchases On January 19, 2021, AAC entered into a purchase agreement (the “Purchase Agreement”) with AFG and certain funds or accounts (the “Note Holders”), pursuant to which (i) the Note Holders agreed to sell to AAC all of the individual beneficial interests (the “Interests”) in the 5.1% senior notes due August 28, 2039 (the “Corolla Notes”), issued by the Corolla Trust, a Delaware statutory trust formed by AFG in 2014 (the "Corolla Trust")(see Note 12. Variable Interest Entities for a discussion of the establishment of the Corolla Trust), (ii) AFG agreed to sell to AAC the owner trust certificate for the Corolla Trust (the “Corolla Certificate”), which constituted all of the equity interests in the Corolla Trust, and (iii) AAC agreed to exchange the Interests and the Corolla Certificate for AAC’s surplus notes (collectively, the “Corolla Note Exchange”). The Note Holders held 100% of the outstanding Corolla Notes. Pursuant to the Purchase Agreement, each $1.00 principal amount of the Corolla Notes (and the associated amount of accrued and unpaid interest thereon) was exchanged for $0.9125 principal amount of surplus notes (and the associated amount of accrued and unpaid interest thereon) on the date of the consummation of the Corolla Note Exchange (the “Closing”). In addition, every $1.00 principal amount of the Corolla Certificate (and the associated amount of accrued and unpaid interest thereon) was exchanged for $0.64 principal amount of surplus notes (and the associated amount of accrued and unpaid interest thereon) on the date of Closing. The Closing occurred on January 22, 2021. At the Closing AAC issued $267 aggregate principal amount of surplus notes to consummate the Corolla Note Exchange and acquire all of the interests in the Corolla Trust. Subsequent to the closing the Corolla Trust was dissolved and the junior surplus note that had been deposited in the Corolla Trust by AFG in 2014 was canceled. In February 2021, AAC entered into a purchase agreement pursuant to which the holder of $15 principal amount of 5.1% junior surplus notes issued by AAC agreed to sell such notes to AAC in exchange for surplus notes (the "JSN Exchange"). Pursuant to the purchase agreement, each $1.00 principal amount of the junior surplus notes (and the associated amount of accrued and unpaid interest thereon) was exchanged for $0.8581 principal amount of surplus notes (and the associated amount of accrued and unpaid interest thereon). The closing of the JSN Exchange occurred on February 11, 2021, when AAC issued approximately $13 aggregate principal amount of surplus notes. Subsequent to the closing of the JSN Exchange the junior surplus notes were canceled. As a result of the Corolla Note Exchange and the JSN Exchange, AAC no longer has any junior surplus notes outstanding. The surplus notes exchanged pursuant to the Corolla Note Exchange and the JSN Exchange are part of the same series as, and rank equally with, the surplus notes previously issued by AAC. The Company recorded a gain of $33 for the year ended December 31, 2021, arising from AAC's purchases of junior surplus notes below their carrying values which is reported within Net realized gains (losses) on extinguishment of debt in the Consolidated Statements of Total Comprehensive Income (Loss). In addition, the Company recorded a gain of $4 for the year ended December 31, 2021, from the exchange of the Corolla Certificate held by AFG above its carrying value, which is reported within Net realized investment gains (losses) in the Consolidated Statements of Total Comprehensive Income (Loss). During 2022, AAC repurchased $266 current par of surplus notes from third party holders below the carrying value of the surplus notes including accrued interest, resulting in a gain of $134 which is reported within Net realized gains (losses) on extinguishment of debt in the Consolidated Statements of Total Comprehensive Income (Loss) for the year ended December 31, 2022. In addition, in November 2022, AAC purchased all of the remaining surplus notes received by AFG following execution of the Corolla Trust Purchase Agreement described above. AAC's repurchase of surplus notes from AFG had no impact on the consolidated financial statements of the Company. Puerto Rico Our financial guarantee insured exposure to Puerto Rico (the "Commonwealth") consisted of several different issuing entities (all below investment grade and whereby AAC has paid substantial claims since 2016) that have been part of the debt restructuring process under the Puerto Rico Oversight, Management, and Economic Stability Act (“PROMESA”), a U.S. federal law enacted in 2016 that, among other things, established a financial oversight board (the “FOMB”) and provided for a process for restructuring debt that roughly follows U.S. Bankruptcy laws. As of December 6, 2022, all AAC-insured Puerto Rico obligations have been restructured under PROMESA via court-approved plans of adjustment or qualifying modifications. Secured Note Refinancing On July 6, 2021, a newly formed variable interest entity and wholly-owned subsidiary of AFG, Sitka Holdings, LLC (“Sitka”), issued $1,175 par amount of LIBOR plus 4.5% senior secured notes due 2026 (the “Sitka Senior Secured Notes”). In connection with the issuance and sale of the Sitka Senior Secured Notes, AAC issued a secured note to Sitka in the same amount and with the same interest rate and maturity date as the Sitka Senior Secured Notes (the "Sitka AAC Note"). The proceeds from this offering of $1,163 were used to fund a
Settlement of RMBS Litigation and Redemption of Secured Notes	Settlement of RMBS Litigations and Redemption of Secured Notes: Settlement of RMBS Litigations: In October 2022, AAC entered into a Settlement Agreement and Release (the “BOA Settlement Agreement”) with Bank of America Corporation and certain affiliates thereof (together, the “BOA Parties”) pursuant to which the BOA Parties paid AAC the sum of $1,840 (the “BOA Settlement Payment”) following the dismissal of AAC’s lawsuits against the BOA Parties concerning certain residential mortgage-backed securities (“RMBS”) trusts, and the withdrawal by AAC of its objections, including any pending appeals, concerning the settlements that were the subject of certain trust instructional proceedings. The BOA Settlement Payment received in October 2022 significantly reduced the subrogation recoverable asset on the Consolidated Balance Sheet. In exchange for the BOA Settlement Payment, AAC, on its own behalf and on behalf of its affiliates, agreed to release the BOA Parties and related parties (the “Released Parties”) from claims asserted or which could have been asserted in AAC’s pending litigations against the BOA Parties as well as claims that AAC and its affiliates ever had, may currently have or may have in the future against the Released Parties, subject to certain limited exceptions. The BOA Settlement Agreement also requires AAC to dismiss other pending claims against the Released Parties, and to generally refrain from, and in certain situations hold the Released Parties harmless with respect to, certain actions taken by AAC with respect to RMBS trusts created prior to the date of the BOA Settlement Agreement involving the Released Parties. The BOA Settlement Payment included recoveries from litigations for alleged breaches of contractual obligations and fraud by the BOA Parties. Management allocated the BOA Settlement Payment to each of the litigations based on previously developed valuations of each individual litigation. The portion of the BOA Settlement Payment allocated to fraud litigation recoveries has been recorded as a litigation recovery in the Statement of Comprehensive Income (Loss). On December 29, 2022, AAC entered into a Settlement Agreement and Release (the “Nomura Settlement Agreement”) with Nomura Credit & Capital, Inc. (“Nomura”) to settle its litigation against Nomura concerning certain RMBS trusts (the “Trusts”). Pursuant to the Nomura Settlement Agreement, Nomura made a cash payment to AAC of $140 (the "Nomura Settlement Payment"), and AAC and Nomura agreed to release each other and their respective affiliates and related persons from any claims relating to the Trusts, the financial guaranty policies issued by AAC in connection with Trusts (other than AAC’s obligations to pay insurance claims under such policies), the securities related to the Trusts, and the mortgage loans related to the Trusts. The Nomura Settlement Payment received in January 2023 will further reduce the subrogation recoverable asset on the Consolidated Balance Sheet. Redemption of Notes: During 2022 and 2023, AAC wholly redeemed its secured debt, in accordance with the terms of such debt, utilizing the BOA Settlement Payment, the Nomura Settlement Payment and other resources as follows: • Effective October 29, 2022, AAC wholly redeemed the Sitka AAC Note from the BOA Settlement Payment, for $1,218 (a price equal to 103% of the principal amount plus accrued and unpaid interest) and Sitka wholly redeemed the Sitka Senior Secured Notes for the same amount. Ambac recorded a loss of $53 reported in Net realized gains (losses) on extinguishment of debt in the Consolidated Statements of Total Comprehensive Income (Loss) for difference between the carrying value of the Sitka AAC Note and the redemption amount paid, excluding accrued interest. • Effective October 29, 2022, AAC applied Net Proceeds (as defined below) of approximately $213 from the BOA Settlement Payment to partially redeem Tier 2 Notes plus accrued and unpaid interest as of the date of redemption. The Tier 2 Notes were secured by proceeds from RMBS litigations net of reinsurance (“Net Proceeds”) in excess of $1,600 and were subject to mandatory redemption from Net Proceeds in excess of $1,600. • Effective January 15, 2023, AAC applied the Net Proceeds of $140 from the Nomura Settlement Payment plus approximately $6 from other sources to fully redeem the remaining Tier 2 Notes plus accrued and unpaid interest in the amount of approximately $146 as of the date of redemption. See Note 13. Long-term Debt in the Notes to the Consolidated Financial Statements included in Part II, Item 8 in this Annual Report on Form 10-K for the year ended December 31, 2022, for a description of Sitka, the Sitka AAC Note, the Sitka Senior Secured Notes and the Tier 2 Notes. AAC also invested a portion of its assets in the Sitka Senior Secured Notes, reported as Fixed maturity securities - available-for-sale on the Consolidated Balance Sheet and recorded a realized investment gain of $5 in the Consolidated Statements of Total Comprehensive Income (Loss) on the redemption date. Impact to the Consolidated Statement of Comprehensive Income (Loss): The total gain recognized in net income attributable to common stockholders related to entering into the BOA Settlement Agreement and the Nomura Settlement Agreement, including the redemption of the Sitka AAC Note following the BOA Settlement, was as follows: Third Fourth Full Losses and loss benefit (1) $ 319 $ 43 $ 362 Litigation recoveries — 126 126 Net realized gains (losses) on extinguishment of debt — (53) (53) Net investment gains (losses), including impairments — 5 5 Impact to net income attributable to common stockholders $ 319 $ 121 $ 440 (1) Full year 2022 losses and loss benefit relating to R&W recoveries were $123.

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Operating Leased Assets [Line Items]
Consolidation	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. The usual condition for a controlling financial interest is ownership of a majority of the voting interests of an entity. However, a controlling financial interest may also exist in entities, such as VIEs, through arrangements that do not involve controlling voting interests. A VIE is an entity: a) that lacks enough equity investment at risk to permit the entity to finance its activities without additional subordinated financial support from other parties; or b) where the group of equity holders does not have: (1) the power, through voting rights or similar rights, to direct the activities of an entity that most significantly impact the entity’s economic performance; (2) the obligation to absorb the entity’s expected losses; or (3) the right to receive the entity’s expected residual returns. The determination of whether a variable interest holder is the primary beneficiary involves performing a qualitative analysis of the VIE that includes, among other factors, its capital structure, contractual terms including the rights of each variable interest holder, the activities of the VIE, whether the variable interest holder has the power to direct the activities of a VIE that most significantly impact the VIE’s economic performance, whether the variable interest holder has the obligation to absorb losses of the VIE that could potentially be significant to the VIE or the right to receive benefits from the VIE that could potentially be significant to the VIE, related party relationships and the design of the VIE. An entity that is deemed the primary beneficiary of a VIE is required to consolidate the VIE. Refer to Note 12. Variable Interest Entities
Unconsolidated Financial Information	AFG Unconsolidated Financial InformationFinancial information of AFG is presented in Schedule II in this Annual Report on Form 10-K as of December 31, 2022 and 2021 and for the years ended December 31, 2022, 2021 and 2020. Investments in subsidiaries are accounted for using the equity method of accounting in Schedule II.
Financing Receivable, Allowance for Credit Losses, Policy for Uncollectible Amounts	Measurement of Credit Losses on Financial Instruments (CECL) Ambac measures credit losses on financial assets that are not accounted for at fair value through net income in accordance with the Current Expected Credit Loss standard or "CECL". The CECL impact on available-for-sale debt securities is discussed in the Investments sub-section below. The CECL impact on amortized cost assets is addressed in the Premium, Reinsurance Recoverables and Loan sub-sections below. These amortized cost assets reflect management's current estimate of all expected lifetime credit losses. The estimate of expected lifetime credit losses considers historical information, current information, as well as reasonable and supportable forecasts. Expected lifetime credit losses for amortized cost assets are recorded as an allowance for credit losses, with subsequent increases or decreases in the allowance reflected in net income each period.
Investments	Investments The Investments - Debt Securities Topic of the ASC requires that all debt instruments be classified in Ambac’s Consolidated Balance Sheets according to their purpose and, depending on that classification, be carried at either cost or fair market value. Ambac’s non-VIE debt investment portfolio is accounted for on a trade-date basis and consists primarily of: • Investments in fixed maturity securities are either classified as available-for-sale or trading as defined by the Investments - Debt Securities Topic of the ASC. Available-for-sale debt securities are reported in the financial statements at fair value with unrealized gains and losses, net of deferred taxes, reflected in Accumulated Other Comprehensive Income (Loss) in Stockholders’ Equity and computed using amortized cost as the basis. For purposes of computing amortized cost, premiums and discounts are accounted for using the effective interest method over the term of the security. For structured debt securities with a large underlying pool of homogenous loans, such as mortgage-backed and asset-backed securities, premiums and discounts are adjusted for the effects of actual and anticipated prepayments. For other fixed maturity securities, such as corporate and municipal bonds, discounts are amortized or accreted over the remaining term of the securities and premiums are amortized to the earliest call date. Investments in fixed maturity securities classified at trading are reported in the financial statements at fair value with unrealized gains and losses included in Net investment income on the Statement of Total Comprehensive Income (Loss). • Equity interests in pooled investment funds which are accounted for in accordance with the Investments - Equity Securities Topic of the ASC and reported as Other investments on the Consolidated Balance Sheet with income reported through Net investment income on the Statement of Total Comprehensive Income (Loss). Equity interests in the form of common stock or in-substance common stock are classified as trading securities and reported at fair value while limited partner interests in such funds are reported using the equity method. • Preferred equity investments that do not have readily determinable fair values and are carried at cost, less any impairments as permitted under the Investments — Equity Securities Topic of the ASC. VIE investments in fixed maturity securities are carried at fair value as they are classified as either available-for-sale or trading as defined by the Investments — Debt Securities Topic of the ASC, or accounted for under the fair value option election. For additional information about VIE investments, including fair value by asset-type, see Note 12. Variable Interest Entities . Fair value is based primarily on quotes obtained from independent market sources. When quotes for fixed maturity securities are not available or cannot be reasonably corroborated, valuation models are used to estimate fair value. These models include estimates, made by management, which utilize current market information. When fair value is not readily determinable for pooled investment funds, the investments are valued using net asset value ("NAV") as a practical expedient as permitted under the Fair Value Measurement Topic of the ASC. Investment valuations could differ materially from amounts that would actually be realized in the market. Realized gains and losses on the sale of investments are determined on the basis of specific identification. Refer to Note 6. Fair Value Measurements for further description of the methodologies used to determine the fair value of investments, including model inputs and assumptions where applicable. Ambac has a formal credit impairment review process for fixed maturity available-for-sale securities in its investment portfolio. Ambac conducts a review each quarter to identify and evaluate investments that have indications of impairment in accordance with the Investments - Debt Securities Topic of the ASC. Under CECL, factors considered to identify and assess securities for other than temporary impairment included: (i) fair values that have declined by 20% or more below amortized cost; (ii) recent downgrades by rating agencies; (iii) the financial condition of the issuer and financial guarantor, as applicable, and an analysis of projected defaults on the underlying collateral; (iv) whether scheduled interest payments are past due; (v) whether Ambac has the intent to sell the security; and (vi) whether it is more likely than not that Ambac will be required to sell a security before the anticipated recovery of its amortized cost basis. The recognition of credit impairment losses for available-for-sale debt securities are recorded as an allowance for credit losses with an offsetting charge to net income. Improvements to estimated credit losses for available-for-sale debt securities are recognized immediately in net income. If we believe a decline in the fair value of a particular fixed maturity available-for-sale investment is not credit impaired, we record the decline as an unrealized loss net of tax in Accumulated Other Comprehensive Income (Loss) in Stockholders’ Equity on our Consolidated Balance Sheets. If management either: (i) has the intent to sell its investment in a debt security or (ii) determines that the Company more likely than not will be required to sell the debt security before its anticipated recovery of the amortized cost basis less any current period credit impairment, then an impairment charge is recognized in earnings, with the amortized cost of the security written-down to fair value. The evaluation of securities for credit impairment is a quantitative and qualitative process, which is subject to risks and uncertainties and is intended to determine whether, and to what extent, declines in the fair value of investments should be recognized in current period earnings. The risks and uncertainties include changes in general economic conditions, the issuer’s or guarantor’s financial condition and/or future prospects, the impact of regulatory actions on the investment portfolio, the performance of the underlying collateral, the effects of changes in interest rates or credit spreads and the expected recovery period. With respect to Ambac insured securities owned, future cash flows used to measure credit impairment represents the sum of (i) the bond’s intrinsic cash flows and (ii) the estimated AAC claim payments. Ambac’s assessment about whether a decline in value is considered a credit impairment reflects management’s current judgment regarding facts and circumstances specific to a security and the factors noted above. If that judgment changes, Ambac may ultimately record a charge for credit impairment in future periods. Ambac has made certain accounting policy elections related to accrued interest receivable ("AIR") for available-for-sale investments under CECL. Elections include: i) not measuring AIR for credit impairment, instead AIR is written off when it becomes 90 days past due; ii) writing off AIR by reversing interest income; iii) presenting AIR separately in Other Assets on the balance sheet and iv) excluding AIR from amortized cost balances in required CECL disclosures found in Note 5. Investments. AIR at December 31, 2022 and 2021 was $10 and $10, respectively. Refer to Note 5. Investments for further credit impairment disclosures.
Net Premiums Earned	Premiums Legacy Financial Guarantee Insurance: Gross premiums were received either upfront or in installments. For premiums received upfront, an unearned premium revenue (“UPR”) liability was established, which was initially recorded as the cash amount received. For installment premium transactions, a premium receivable asset and offsetting UPR liability was initially established in an amount equal to: (i) the present value of future contractual premiums due (the “contractual” method) or (ii) if the underlying insured obligation is a homogenous pool of assets which are contractually prepayable, the present value of premiums to be collected over the expected life of the transaction (the “expected” method). An appropriate risk-free rate corresponding to the weighted average life of each policy and currency is used to discount the future premiums contractually due or expected to be collected. For example, U.S. dollar exposures are discounted using U.S. Treasury rates while exposures denominated in a foreign currency are discounted using the appropriate risk-free rate for the respective currency. The weighted average risk-free rate at December 31, 2022 and 2021, was 3.0%. and 2.2%, respectively, and the weighted average period of future premiums used to estimate the premium receivable at December 31, 2022 and 2021, was 8.0 years and 8.0 years, respectively. Insured obligations consisting of homogeneous pools for which Ambac uses expected future premiums to estimate the premium receivable include residential mortgage-backed securities ("RMBS"). As prepayment assumptions change for homogenous pool transactions, or if there is an actual prepayment for a “contractual” method installment transaction, the related premium receivable and UPR are adjusted in equal and offsetting amounts with no immediate effect on earnings using new premium cash flows and the then current risk-free rate corresponding to the initial weighted average life of the related policy. For both upfront and installment premium policies, premium revenues are earned over the life of the financial guarantee contract in proportion to the insured principal amount outstanding at each reporting date (referred to as the level-yield method). For installment paying policies, the premium receivable discount, equating to the difference between the undiscounted future installment premiums and the present value of future installment premiums, is accreted as premiums earned in proportion to the premium receivable balance at each reporting date. When a bond issue insured by Ambac has been retired early, typically due to an issuer call, any remaining UPR is recognized at that time to the extent the financial guarantee contract is legally extinguished, causing accelerated premium revenue. For installment premium paying transactions, we offset the recognition of any remaining UPR by the reduction of the related premium receivable to zero (as it will not be collected as a result of the retirement), which may cause negative accelerated premium revenue. Certain obligations insured by Ambac have been legally defeased whereby government securities are purchased by the issuer with the proceeds of a new bond issuance, or less frequently with other funds of the issuer, and held in escrow. The principal and interest received from the escrowed securities are then used to retire the Ambac-insured obligations at a future date either to their maturity date (a refunding) or a specified call date (a pre-refunding). Ambac has evaluated the provisions in policies issued on these obligations and determined those insurance policies have not been legally extinguished. For policies with refunding securities, premium revenue recognition is not impacted as the escrowed maturity date is the same as the previous legal maturity date. For policies with pre-refunding securities, the maturity date of the pre-refunded security has been shortened from its previous legal maturity. Although premium revenue recognition has not been accelerated in the period of the pre-refunding, it results in an increase in the rate at which the policy's remaining UPR is to be recognized. For financial guarantee contracts, the issuer's ability and willingness to pay its insured debt obligation impacts the payment of policy losses by Ambac as well as the receipt of premiums from the issuer. As such, management leverages its existing loss reserve estimation process to evaluate credit impairment for premium receivables. Key factors in assessing credit impairment include historical premium collection data, internal risk classifications, credit ratings and loss severities. For structured finance transactions involving special purpose entities, we further evaluate the priority of premiums paid to Ambac within the contractual waterfall, as required by bond indentures. Ambac has a formal quarterly credit impairment review process for premium receivables. Under CECL, management utilizes either a discounted cash flow ("DCF") or probability of default/loss given default ("PD/LGD") approach to estimate credit impairment. The DCF approach utilizes expected cash flows developed by Ambac's Risk Management Group using the same (or similar) models used for estimating loss reserves where such models can identify shortfalls in premiums. Credit impairment using the DCF approach is equal to the difference between amortized cost and the present value of expected cash flows. Credit impairment under the PD/LGD approach is the product of (i) the premium receivable carrying value, (ii) internally developed default probability (considering internal ratings and average life), and (iii) internally developed loss severities. Refer to Note 8. Insurance Contracts for further credit impairment disclosures. AAC has reinsurance in place pursuant to surplus share treaties and facultative reinsurance agreements. Similar to gross premiums, premiums ceded to reinsurers were paid either upfront or in installments. For premiums paid upfront, a deferred ceded premium asset was established which is initially recorded as the cash amount paid. For installment premiums, a ceded premiums payable liability and offsetting deferred ceded premium asset were initially established in an amount equal to: i) the present value of future contractual premiums due or ii) if the underlying insured obligation is a homogenous pool of assets, the present value of expected premiums to be paid over the life of the transaction. An appropriate risk-free rate corresponding to the weighted average life of each policy and exposure currency is used to discount the future premiums contractually due or expected to be collected. Premiums ceded to reinsurers reduce the amount of premiums earned by Ambac from its financial guarantee insurance policies. For both upfront and installment premiums, ceded premiums written are primarily recognized in earnings in proportion to and at the same time as the related gross premium revenue is recognized. For premiums paid to reinsurers on an installment basis, Ambac records the present value of future ceding commissions as an offset to ceded premiums payable, using the same assumptions noted above for installment premiums. Specialty Property and Casualty Insurance: Gross written premiums on insurance policies are recorded at the inception of the policy and can be received on an upfront or installment basis. Ceded premiums written are based on contractual terms applied against related gross written premiums. Premiums, net of reinsurance, are recognized as revenue on a daily pro-rata basis over the term of the insured risk. Unearned premiums and Deferred ceded premiums represents the portion of gross and ceded premiums written that relate to unexpired risk, respectively.
Loans	Loans Loans are reported at either their outstanding principal balance less unamortized discount or at fair value. • Loans not held by consolidated VIEs are reported at their outstanding principal balance less unamortized discount and are reported within Other assets on the Consolidated Balance Sheet. Interest income is earned using the effective interest method based upon interest accrued on the unpaid principal balance adjusted for accretion of discounts. A loan is considered impaired when, based on the financial condition of the borrower, it is probable that Ambac will be unable to collect all principal and interest due according to the contractual terms of the loan agreement. Ambac has a formal quarterly credit impairment review process for these loans. The key factors in assessing credit impairment are internal credit ratings and loss severities. Management utilizes a PD/LGD approach, similar to the one described above for financial guarantee premium receivables, which is applied to the loan carrying value. • Loans held by VIEs consolidated as required under the Consolidation Topic of the ASC are carried at fair value under the fair value option election with changes in fair value recorded in Income (loss) on variable interest entities on the Consolidated Statements of Total Comprehensive
Derivative Contracts	Derivative Contracts The Company has entered into derivative contracts primarily to hedge certain economic risks inherent in its asset and liability portfolios. None of Ambac’s derivative contracts are designated as hedges under the Derivatives and Hedging Topic of the ASC. Ambac's derivatives consist primarily of interest rate swaps and futures contracts. • Ambac maintains a portfolio consisting primarily of interest rate swaps and futures contracts to economically hedge interest rate risk in the financial guarantee and investment portfolios. While this portfolio also includes certain legacy interest rate swaps executed in connection with financial guarantee client financings, the interest rate derivatives portfolio is managed on the basis of its net sensitivity to changes in interest rates. Changes in the fair value of these interest rate derivatives are recorded, along with changes in fair value of other derivative contracts, within Net gains (losses) on derivative contracts on the Consolidated Statements of Total Comprehensive Income (Loss). • VIEs consolidated under the Consolidation Topic of the ASC entered into derivative contracts to meet specified purposes within their securitization structure. Changes in fair value of consolidated VIE derivatives are included within Income (loss) on variable interest entities on the Consolidated Statements of Total Comprehensive Income (Loss). All derivatives are recorded on the Consolidated Balance Sheets at fair value on a gross basis; assets and liabilities are netted by counterparty only when a legal right of offset exists. Variation payments on centrally cleared swaps and futures contracts are considered settlements of the associated derivative balances and are reflected as a reduction to derivative liabilities or assets on the Consolidated Balance Sheets. For other derivatives, Ambac has determined that the amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral may not be used to offset amounts due under the derivative instruments in the normal course of settlement. Therefore, such amounts are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement and are included in Other assets on the Consolidated Balance Sheets. Refer to Note 10. Derivative Instruments for further discussion of the Company’s use of derivative instruments and their impact of the consolidated financial statements. Refer to Note 6. Fair Value Measurements
Goodwill and Intangible Assets, Policy	Goodwill Goodwill is attributable to acquisitions, discussed in Note 4. Business Combination and represents the acquisition cost in excess of the fair value of net assets acquired, including identifiable intangible assets. Goodwill is assigned at acquisition to the applicable reporting unit of the acquired entity giving rise to the goodwill. Goodwill is not amortized but is subject to impairment testing. Goodwill impairment tests are performed annually or more frequently if circumstances indicate a possible impairment. Ambac tests goodwill for impairment as of October 1st of each year. If, after assessing qualitative factors, management believes it is more likely than not that the fair value of a reporting unit is less than its carrying amount, a quantitative impairment evaluation is performed. Management also has the option to bypass the qualitative evaluation and proceed directly to the quantitative evaluation. The quantitative test compares the estimated fair value of the reporting unit with its carrying value (including goodwill and identifiable intangible assets). An impairment is recognized for the excess of the carrying amount of the reporting unit over it estimated fair value. If the reporting unit’s estimated fair value exceeds its carrying value, goodwill is not impaired. There have been no accumulated impairment losses since goodwill was established. Intangible Assets Financial Guarantee Insurance intangible: Upon Ambac's emergence from bankruptcy in 2013, an insurance intangible asset was recorded which represented the difference between the fair value and aggregate carrying value of the financial guarantee insurance and reinsurance assets and liabilities. The carrying values of financial guarantee insurance and reinsurance contracts continue to be reported and measured in accordance with their existing accounting policies. Pursuant to the Financial Services-Insurance Topic of the ASC, the insurance intangible is to be measured on a basis consistent with the related financial guarantee insurance and reinsurance contracts. The initial insurance intangible asset was assigned to groups of insurance and reinsurance contracts with similar characteristics and has been amortized using a level-yield method based on par exposure of the related groups. Finite-lived intangibles: Ambac acquired identifiable intangible assets attributable to the Xchange, All Trans and Capacity Marine acquisitions further discussed in Note 4. Business Combination . The intangible assets primarily relate to distribution relationships, non-compete agreements and trade names, all of which have finite lives and are amortized over their estimated useful lives using the straight- line method. The Company tests finite-lived acquired intangible assets for impairment if certain events occur or circumstances change indicating that the carrying amount of the intangible asset may not be recoverable. The carrying amount of the intangible asset is not recoverable if it exceeds the projected undiscounted cash flows expected to result from the use and eventual disposal of the asset or asset group. If deemed unrecoverable, an impairment loss is recognized for the excess carrying amount over the fair value. There have been no accumulated impairment losses since these finite-lived intangible assets were established. Indefinite-lived intangibles Ambac acquired identifiable intangible assets attributable to its acquisitions of admitted carriers in both 2021 and 2022, which were accounted for as asset acquisitions. The intangible assets relate to insurance licenses which have indefinite lives and therefore are not amortized. The useful lives are re-evaluated each period to determine whether facts and circumstances continue to support an indefinite life. The Company tests indefinite-lived acquired intangible assets for impairment annually or more frequently if circumstances indicate a possible impairment. Ambac tests indefinite-lived intangibles for impairment as of October 1st of each year. If, after assessing qualitative factors, management believes it is more likely than not that the intangible assets are impaired, a quantitative impairment evaluation is performed. Management also has the option to bypass the qualitative evaluation and proceed directly to the quantitative evaluation. The quantitative test compares the estimated fair value of the intangible asset with its carrying value. An impairment is recognized for the excess of the carrying amount of the intangible asset over it estimated fair value. If the asset’s estimated fair value exceeds its carrying value, the intangible asset is not impaired. There have been no accumulated impairment losses since these indefinite-lived intangible assets were established.
Restricted Cash	Restricted Cash Cash that we do not have the right to use for general purposes is recorded as restricted cash in our consolidated balance sheets. Restricted cash includes (i) consolidated variable interest entity cash restricted to support the obligations of the consolidated VIEs and (ii) fiduciary cash held by Ambac's insurance distribution subsidiaries as described below. Fiduciary Funds: As an intermediary, we hold funds, generally in a fiduciary capacity, for the account of third parties, typically as the result of premiums received from retail brokers or insureds that are in transit to insurers and claims due that are in transit from insurers. Since fiduciary assets are not available for corporate use, they are shown in the consolidated balance sheets as restricted cash and we present an equal and corresponding fiduciary liability relating to these funds representing amounts or claims or premiums due on our consolidated balance sheets (included in Other liabilities). Fiduciary funds are generally required to be kept in bank accounts subject to guidelines which emphasize capital preservation and liquidity. The Company is entitled to retain investment income earned on certain of these fiduciary funds in accordance with industry custom and practice and, in some cases, as supported by agreements with insureds. Restricted cash for net uncollected premiums and claims and the related fiduciary liabilities were $14 and $5 at December 31, 2022 and 2021, respectively.
Loss Reserves	Loss and Loss Adjustment Expenses Legacy Financial Guarantee: The loss and loss adjustment expense reserve (“loss reserve”) policy relates only to Ambac’s non-derivative financial guarantee insurance business for insurance policies issued to beneficiaries, including VIEs, for which we do not consolidate the VIE. Losses and loss expenses are based upon estimates of the ultimate aggregate losses inherent in the insured portfolio as of the reporting date. The policy for derivative contracts is discussed in the “Derivative Contracts” section above. A loss reserve is recorded on the balance sheet on a policy-by-policy basis based upon the present value ("PV") of expected net claim cash outflows or expected net recovery cash inflows, discounted at risk-free rates. The estimate for future net cash flows consider the likelihood of all possible outcomes that may occur from missed principal and/or interest payments on the insured obligation. This estimate also considers future recoveries related to breaches of contractual representations and warranties by RMBS transaction sponsors (prior to the settlements as more fully described in Note 1. Background and Business Description ), remediation strategies and other contractual or subrogation-related cash flows. • Net claim cash outflow policies represent contracts where the PV of expected cash outflows are greater than the PV of expected recovery cash inflows. For such policies, a “loss and loss adjustment expense reserves” liability is recorded for the excess of the PV of expected net claim cash outflows over the unearned premium revenue. • Net recovery cash inflow policies represent contracts where the PV of expected recovery cash inflows are greater than the PV of expected claim cash outflows. For such policies, a “Subrogation recoverable” asset is recorded. The evaluation process for determining expected losses is subject to certain judgments based on our assumptions regarding the probability of default by the issuer of the insured security, probability of settlement outcomes (which may include commutation settlements, refinancing and/or other settlement outcomes) and expected severity of credits for each insurance contract. Ambac’s loss reserves are based on management’s ongoing review of the financial guarantee credit portfolio. Active surveillance of the insured portfolio enables Ambac’s Risk Management Group ("RMG") to track credit migration of insured obligations from period to period and update internal classifications and credit ratings for each transaction. Non-adversely classified credits are assigned a Class I rating while adversely classified credits are assigned a rating of Class IA through Class V. The criteria for an exposure to be assigned an adversely classified credit rating includes the deterioration of an issuer’s financial condition, underperformance of the underlying collateral (for collateral dependent transactions such as mortgage-backed or student loan securitizations), poor performance by the servicer of the underlying collateral and other adverse economic events or trends. The servicer of the underlying collateral of an insured securitization transaction is a consideration in assessing credit quality because the servicer’s performance can directly impact the performance of the related issue. All credits are assigned risk classifications by RMG using the following guidelines: CLASS I – “Fully Performing - Meets Ambac Criteria with Remote Probability of Claim” - Credits that demonstrate adequate security and structural protection with a strong capacity to pay interest, repay principal and perform as underwritten. Factors supporting debt service payment and performance are considered unlikely to change and any such change would not have a negative impact upon the fundamental credit quality. Through ongoing surveillance, Ambac may also designate Class I credits into one or more of the following categories: • Survey List - credits that may lack information or demonstrate a weakness but further deterioration is not expected. • Watch List - credits that demonstrate the potential for future material adverse development due to such factors as long-term uncertainty about a particular sector, a certain structural element, large exposure concentration or concern related to the issuer or transaction or the overall financial and economic sustainability. CLASS IA – “Potential Problem with Risks to be Dimensioned” - Credits that are fully current and monetary default or claims-payment are not anticipated. The issuer’s financial condition may be deteriorating or the credits may lack adequate collateral. A structured financing may also evidence weakness in its fundamental credit quality as evidenced by its under-performance relative to its modeled projections at underwriting, issues related to the servicer’s ability to perform or questions about the structural integrity of the transaction. While certain of these credits may still retain an investment grade rating, they usually have experienced or are vulnerable to a ratings downgrade. Further investigation is required to dimension and correct any deficiencies. A complete legal review of documents may be required. An action plan should be developed with triggers for future classification changes upward or downward. CLASS II – “Substandard Requiring Intervention” - Credits whose fundamental credit quality has deteriorated to the point that timely payment of debt service may be jeopardized by adversely developing trends of a financial, economic, structural, managerial or political nature. No claim payment is currently foreseen but the probability of loss or claim payment over the life of the transaction is now existent (generally 10% or greater probability). Class II credits may be border-line or below investment grade (BBB- to B). Prompt and sustained action must be taken to execute a comprehensive loss mitigation plan and correct deficiencies. CLASS III – “Doubtful with Clear Potential for Loss” - Credits whose fundamental credit quality has deteriorated to the point that timely payment of debt service has been or will be jeopardized by adverse trends of a financial, economic, structural, managerial or political nature which, in the absence of positive change or corrective action, are likely to result in a loss. The probability of monetary default or claims paying over the life of the transaction is generally 50% or greater. Full exercise of all available remedial actions is required to avert or minimize losses. Class III credits will generally be rated below investment grade (B to CCC). CLASS IV – “Imminent Default or Defaulted” - Monetary default or claim payments have occurred or are expected imminently. Class IV credits are generally rated D. CLASS V – “Fully Reserved” - The credit has defaulted and payments have occurred. The claim payments are scheduled and known, reserves have been established to fully cover such claims, and no claim volatility is expected. The population of credits evaluated in Ambac’s loss reserve process are: (i) all adversely classified credits and ii) non-adversely classified credits which had an internal Ambac rating downgrade since the transaction’s inception. One of two approaches is then utilized to estimate losses to ultimately determine if a loss reserve should be established. • The first approach is a statistical expected loss approach, which considers the likelihood of all possible outcomes. The “base case” statistical expected loss is the product of: (i) the par outstanding on the credit; (ii) internally developed default information (taking into consideration internal ratings and average life of an obligation); (iii) internally developed loss severities; and (iv) a discount factor. The loss severities and default information are based on rating agency information, are specific to each bond type and are established and approved by senior RMG officers. For certain credit exposures, Ambac’s additional monitoring, loss remediation efforts and probabilities of potential settlement outcomes may provide information relevant to adjust this estimate of “base case” statistical expected losses. Analysts may accept the “base case” statistical expected loss as the best estimate of expected loss or assign multiple probability weighted scenarios to determine an adjusted statistical expected loss that better reflects management’s view of a given transaction’s expected losses, as well as the potential for additional remediation activities (e.g., commutations). • The second approach entails the use of cash-flow based models to estimate expected losses (future claims, net of potential recoveries, expected to be paid to the holder of the insured financial obligation). Ambac’s RMG group will consider the likelihood of all possible outcomes and develop appropriate cash flow scenarios. This approach can include the utilization of internal or third party models and tools to project future losses and resultant claim payment estimates. We utilize cash flow models for RMBS, student loans and other exposures. RMBS and student loan models use historical performance of the collateral pools in order to then derive future performance characteristics, such as default and voluntary prepayment rates, which in turn determine projected future claim payments. In other cases, such as many public finance exposures, including Puerto Rico, we do not specifically forecast resources available to pay debt service in the cash flow model itself. Rather, we consider the issuers’ overall ability and willingness to pay, including the fiscal, economic, legal and political framework to develop projected future claim payment estimates. In this approach, a probability-weighted expected loss estimate is developed based on assigning probabilities to multiple claim payment scenarios and applying an appropriate discount factor. Additionally, we consider the issuer’s ability to refinance an insured issue, Ambac’s ability to execute a potential settlement (i.e., commutation) of the insurance policy, including the impact on future installment premiums, and/or other restructuring possibilities in our scenarios. The commutation scenarios and the related probabilities of occurrence vary by transaction, depending on our view of the likelihood of negotiating such a transaction with issuers and/or investors. The discount factor applied to the statistical expected loss approach is based on a risk-free discount rate corresponding to the remaining expected weighted-average life of the exposure and the exposure currency. For the cash flow scenario approach, discount factors are applied based on a risk-free discount rate term structure and correspond to the date of each respective cash flow payment or recovery and the exposure currency. Discount factors are updated for the current risk-free rate each reporting period. Ambac establishes loss expense reserves based on our estimate of expected net cash outflows for loss expenses, such as legal and consulting costs. Below we provide further details of our loss reserve models for both RMBS and student loan exposures: RMBS Expected Loss Estimate Ambac insures RMBS transactions collateralized by (i) first-lien mortgages; and (ii) second-lien mortgage loans such as closed-end seconds and home equity lines of credit. If the borrower defaults on the payments due under these loans and the property is subsequently liquidated, the liquidation proceeds are first utilized to pay off the first-lien loan (as well as other costs) and any remaining funds are applied to pay off the second-lien loan. As a result of this subordinate position to the first-lien loan, second-lien loans may carry a significantly higher severity in the event of a loss. Ambac primarily utilizes a cash flow model (“RMBS cash flow model”) to develop estimates of projected losses for both our first and second lien transactions. First, the RMBS cash flow model projects collateral performance utilizing: (i) the transaction’s underlying loans' characteristics and status, (ii) projected home price appreciation (“HPA”) and (iii) projected interest rates. Depending on the amount of collateral information available for each transaction, we project such performance either at the loan-level or the deal-level using a variety of data that helps dimension the risk of the loans and/or deals. Observed servicer-level behavior may also have an impact on projected transaction performance. We source HPA projections from a market accepted vendor and interest rate projections are developed from market sources. We use three HPA projection scenarios to develop a base case as well as stress and upside cases. The highest probability is assigned to the base case, with lower probabilities to the stress and upside cases. For the liabilities of the transaction which we insure, we generally utilize waterfall projections generated from a tool provided by a market accepted vendor. This waterfall tool allows us to capture the impact of each transaction’s specific structure (e.g., the waterfall priority of payments, triggers, redemption priority) to generate our specific projected claims profile in the base, upside and downside scenarios. On a monthly basis, we compare monthly claims submitted against the trustees’ reports, waterfall projections and our understanding of the transactions’ structures to identify and resolve discrepancies. In our experience, market performance and model characteristics change and therefore need to be updated and reflected in our models through time. As such, we conduct regular reviews of current models, alternative models and the overall approach to loss estimation. RMBS Representation and Warranty Subrogation Recoveries Prior to the settlement of all representation and warranty ("R&W") litigation settlements in 2022, as discussed in Note 1. Background and Business Description, Ambac recorded, as a component of its loss reserve estimate, subrogation recoverables related to securitized loans in RMBS transactions that breached certain R&W described herein. Generally, the sponsor of an RMBS transaction provided R&W with respect to the securitized loans, including R&W with respect to loan characteristics, the absence of borrower misrepresentations in the underlying loans and other misconduct in the origination process and attesting to the compliance of loans with the applicable underwriting guidelines. In such cases, the sponsor of the transaction is obligated, in accordance with the underlying contract, to repurchase, cure or substitute collateral for any loan that breaches the R&W. • Ambac or its counsel engaged consultants with significant mortgage underwriting experience to review the underwriting documentation for mortgage loans underlying certain insured RMBS transactions with significant collateral losses, resulting in significant claims payments by Ambac. • Ambac's approach used to estimate RMBS R&W subrogation recoverables was based on obtaining loan files from the original pool and conducting loan file re-underwriting to derive a quantum of breaches and an estimated repurchase obligation.. • Multiple probability-weighted scenarios were developed by applying various realization factors to the estimated repurchase obligation. The realization factors in these scenarios reflected Ambac’s own assumptions about the likelihood of outcomes based on all the information available to it including, but not limited to, (i) discussions with external legal counsel and their views on ultimate settlement and/or litigation outcomes; (ii) assessment of the strength of the specific case; (iii) changes in law or developments in RMBS litigation cases that impact our estimated recoveries; and (iv) experience in settling similar claims. The probability weightings were developed based on the unique facts and circumstances for each transaction. The sum of these probability-weighted scenarios represented the undiscounted RMBS R&W subrogation recovery, which was then discounted using a factor derived from a risk-free discount rate term structure that corresponds to the estimated date of each respective recovery. Student Loan Expected Loss Estimate The student loan insured portfolio consists of credits collateralized by private student loans. The calculation of loss reserves for our student loan portfolio involves evaluating numerous factors that can impact ultimate losses. Since our policies cover timely interest and ultimate principal payment, our loss projections must make assumptions for many factors covering a long horizon. Key assumptions that will impact ultimate losses include, but are not limited to, the following: collateral performance (which is highly correlated to the economic environment); interest rates; operating risks associated with the issuer, servicers, special servicers, and administrators; investor appetite for tendering or commuting insured obligations; and as applicable, Ambac’s ability and willingness to commute policies. In addition, we consider in our student loan loss projections the potential impact, if any, of proposed or final regulatory actions or orders, including by the Consumer Financial Protection Bureau ("CFPB"), affecting our insured transactions. We develop and assign probabilities to multiple cash flow scenarios based on each transaction’s unique characteristics. Probabilities assigned are based on available data related to the credit, information from contact with the issuer (if applicable), and any economic or market information that may impact the outcomes of the various scenarios being evaluated. Our base case usually projects deal performance out to maturity using expected loss assumptions. As appropriate, we also develop other cases that incorporate various upside and downside scenarios that may include changes to defaults and recoveries. Specialty Property and Casualty: loss and loss adjustment expense reserves for Everspan represent management's estimate of the ultimate liability for unpaid losses and loss expenses for claims that have been reported and claims that have been incurred but not yet reported ("IBNR") as of the balance sheet date. The reserves are estimated based upon experience and using a variety of actuarial methods. These estimates are reviewed and are subject to the impact of future changes in factors such as claim severity and frequency, underwriting and claims practices, changes in social and economic conditions including the impact of inflation, legal and judicial developments, medical cost trends and upward trends in damage awards. The ultimate amount for loss and loss adjustment expenses may be in excess, or less than, the amounts recorded on our financial statements. Adjustments will be reflected as part of the net increase or reduction in loss and loss adjustment expense reserves in the periods in which they become known. The Company performs a continuing review of its loss and loss adjustment expense reserves, including its reserving techniques and the impact of reinsurance. The reserves are also reviewed by qualified actuaries, including actuaries employed by the Company and third party actuaries. Since the reserves are based on estimates, the ultimate liability may be more or less than such reserves.
Reinsurance Accounting Policy	Reinsurance Recoverable The corresponding loss and loss adjustment expense reserve ceded to reinsurers is reported as reinsurance recoverable on paid and unpaid losses. The reinsurance recoverable from reinsurers is estimated in a manner consistent with the associated loss and loss adjustment expense reserve. Ambac has reinsurance in place pursuant to quota share, surplus share treaty and facultative reinsurance agreements. The reinsurance of risk does not legally relieve Ambac of its original liability to its policyholders. In the event that any of Ambac’s reinsurers are unable to meet their obligations under reinsurance contracts, Ambac would, nonetheless, be liable to its policyholders for the full amount of its policy. To minimize its credit exposure to losses from reinsurer insolvencies, Ambac (i) is entitled to receive collateral from certain reinsurance counterparties pursuant to the terms of the relevant reinsurance contracts and (ii) has certain cancellation rights that can be exercised by Ambac in the event of rating agency downgrades of a reinsurer (among other events and circumstances). For those reinsurance counterparties that do not currently post collateral, Ambac’s reinsurers are well capitalized, highly rated, authorized capacity providers. Under CECL, Ambac has a formal quarterly credit impairment review process whereby Ambac has elected to use the practical expedient of considering the fair value of collateral posted by reinsurers when evaluating credit impairment. To determine the total unsecured recoverable to be evaluated for credit impairment, Ambac nets the reinsurance recoverable amount by ceded premiums payable and the fair value of collateral posted, if any. The key factors in assessing credit impairment for reinsurance recoverables are independent rating agency credit ratings and loss severities. Management utilizes a probability of default/loss given default ("PD/LGD") approach, which is applied to the net unsecured reinsurance recoverable amount. Refer to Note 8. Insurance Contracts
Debt, Policy	Long-term Debt Long-term debt issued by Ambac is carried at par value less unamortized discount. Accrued interest and discount accretion on long-term debt is reported as Interest expense on the Consolidated Statements of Total Comprehensive Income (Loss). To the extent Ambac repurchases or redeems its long-term debt, such repurchases or redemptions may be settled for an amount different than the carrying value of the obligation. Any difference between the payment and carrying value of the obligation is reported in Net realized gains (losses) on extinguishment of debt on the Consolidated Statements of Total Comprehensive Income (Loss). For surplus note repurchases, the pro-rata purchase price related to principal and accrued interest is reported as a financing and operating activity, respectively, on the Statement of Cash Flows. For long-term debt issued by consolidated VIEs in which Ambac's variable interest arises from financial guarantees written by Ambac's subsidiaries ("FG VIEs"), we may elect to use the fair value option on an instrument by instrument basis. When the fair value option is elected, changes in the fair value of the FG VIEs' long-term debt is reported within Income (loss) on variable interest entities in the Consolidated Statements of Total Comprehensive Income (Loss), except for the portion of the total change in fair value of financial liabilities caused by changes in the instrument-specific credit risk which is presented separately in Other comprehensive income (loss). In cases where the fair value option has not been elected, the FG VIEs' long-term debt is carried at par less unamortized discount, with interest expense reported within Income (loss) on variable interest entities in the Consolidated Statements of Total Comprehensive Income (Loss).
Noncontrolling Interest Policy [Policy Text Block]	Noncontrolling Interests Nonredeemable noncontrolling interests At December 31, 2022 and 2021, AAC had 4,596 and 5,501 shares of issued and outstanding Auction Market Preferred Shares ("AMPS") with a liquidation preference of $115 and $138 (reported as nonredeemable noncontrolling interest of $53 and $60 on Ambac's balance sheet), respectively. In 2022, Ambac purchased 905 shares of AMPS for $8. The difference between this amount paid to AMPS holders and the carrying amount was reflected as an increase to Net income attributable to common shareholders for approximately $1. The auction occurs every 28 days and the dividend rate has continuously been reset at the maximum rate of one-month LIBOR plus 200 basis points. Under the terms of the AMPS, dividends may not be paid on the common stock of AAC unless all accrued and unpaid dividends on the AMPS for the then current dividend period have been paid, provided, that dividends on the common stock may be made at all times for the purpose of, and only in such amounts as are necessary for, enabling AFG (i) to service its indebtedness for borrowed money as such payments become due or (ii) to pay its operating expenses. If dividends are paid on the common stock as provided in the prior sentence, dividends on the AMPS become cumulative until the date that all accumulated and unpaid dividends have been paid on the AMPS. AAC has not paid dividends on its AMPS since 2010. Redeemable noncontrolling interests The All Trans, Capacity Marine and Xchange acquisitions, further described in Note 4. Business Combination, resulted in 85%, 80% and 80%, respectively, ownership of the acquired entities by Ambac. Under the terms of the acquisition agreements, Ambac has a call option to purchase the remaining 15%, 20% and 20%, respectively, from the minority owners (i.e., noncontrolling interests) and the minority owners have a put option 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 16. Net Income Per Share. Following is a rollforward of redeemable noncontrolling interest. Years ended December 31, 2022 2021 Beginning balance $ 18 $ 7 Fair value of redeemable noncontrolling interest at acquisition date 5 — Net income attributable to redeemable noncontrolling interest (ASC 810) (1) (1) Adjustment to redemption value (ASC 480 ) (3) 12 Ending Balance $ 20 $ 18
Short-Duration Contracts Revenue Recognition, Policy	Revenue Recognition: Revenues for the Insurance Distribution business operations are recognized in accordance with the Revenue from Contracts with Customers Topic of the ASC. The following steps are applied to recognize revenue: (i) identify the contract(s) with the customer, (ii) identify the performance obligations in the contract(s), (iii) determine the transaction price, and (iv) allocate the transaction price to the performance obligations in the contract and recognize revenue when (or as) the entity satisfies a performance obligation. A performance obligation is satisfied either at a point in time or over time depending on the nature of the product or service provided, and the specific terms of the contract with customers. Insurance Distribution performance obligations consist of underwriting and placing policies with insurers and, for certain products, providing claims servicing. Revenue from insurance policies covering i) limited and short-term medical sold through affinity groups ("Affinity"), ii) commercial and "for hire" auto, and iii) marine and international risks are recognized up front as no further performance obligations exist after policy placement. Revenue from employer stop loss policies ("ESL") is apportioned to policy placement and claims servicing based on the relative stand-alone selling price of the respective performance obligations with policy placement revenue recognized upfront while claims servicing revenue is recognized over the claim adjustment period. Revenue consists of base and profit-sharing commissions. Base commissions, associated with policy placement and claims servicing, are estimated by applying the contractual commission percentages to estimated gross premiums written. Profit-sharing commissions represent variable consideration associated with policy placement only and are estimated based on expected loss ratios and the estimated gross premium for base commissions. Base and profit-sharing commissions are estimated with a constraint applied such that a significant reversal of revenue in the future is not probable. Revenue is reported in Commissions income on the Consolidated Statement of Total Comprehensive Income. Contract assets represent the Company's right to future consideration for services it has already transferred to the customer, which is subject to certain contingencies such as the achievement of loss ratios on underlying insurance policies. Once the right to consideration becomes unconditional, it is reported as a receivable. Contract liabilities represent the Company's obligation to transfer services for which it has already received consideration from the customer. Contract assets and contract liabilities are reported as other assets and other liabilities, respectively, on the Consolidated Balance Sheet. The Company’s costs to fulfill customer contracts relate to certain commissions paid to independent agents for procuring policies. As these costs relate to the Company’s policy placement performance obligation to its customers, they are expensed as incurred. These costs are reported in Commission expenses on the Consolidated Statement of Total Comprehensive Income. The Company does not incur costs related to obtaining customer contracts.
Postretirement and Postemployment Benefits	Postretirement and Postemployment BenefitsAmbac provides postretirement and postemployment benefits, including health and life benefits covering employees who meet certain age and service requirements. Ambac accounts for these benefits under the accrual method of accounting. Amounts related to the postretirement health benefits liability are established and charged to expense based on actuarial determinations.
Long Term Incentive and Stock Compensation Plan	Incentive Compensation Incentive compensation is a key component of our compensation strategy. Incentive compensation has two components: short term incentive compensation (consisting of an annual cash bonus) and long term incentive plan awards (consisting of deferred cash and awards of restricted and performance stock units). Annual decisions with regard to incentive compensation are generally made in the first quarter of each year and are based on the prior year's performance for the Company, the employee and the employee's business unit. In 2020, the Ambac 2013 Incentive Compensation Plan (the “2013 Incentive Plan”) was superseded by the 2020 Incentive Compensation Plan ("2020 Incentive Plan"). Both plans allow for the granting of stock options, restricted stock, stock appreciation rights, restricted and performance units and other awards to employees, directors and consultants that are valued or determined by reference to Ambac's common stock. Under these plans, Ambac has issued both cash and equity awards to US employees and consultants. In connection with the adoption of the 2020 Incentive Plan, all shares reserved but unissued under the 2013 Incentive Plan were transferred to the the 2020 Incentive Plan in addition to any shares underlying outstanding awards under the 2013 Incentive Plan as of June 2, 2020 that subsequently terminate by expiration or forfeiture, cancellation, or otherwise are not issued. Under the 2013 and 2020 Incentive Compensation Plans. Ambac recognizes compensation costs for all equity classified awards granted at fair value, which is measured on the grant date, and records forfeitures for unvested shares only when they occur. For awards that only include service and performance conditions, the fair value is the market price of Ambac stock on the grant date. For awards that also contain a market condition, specifically a total shareholder return ("TSR") modifier, the fair value is estimated using a Monte Carlo simulation. The types of equity awards granted to employees are as follows: • Restricted stock units — only require future service and accordingly the respective fair value is recognized as compensation expense over the relevant service period. • Performance stock units — require both future service and achieving specified performance targets to vest. Certain performance stock unit grants also include a market condition TSR modifier that will cause the total payout at the end the performance period to increase or decrease depending on Ambac's stock performance relative to a peer group. Compensation costs for all performance stock units are only recognized when the achievement of the performance conditions are considered probable. Once deemed probable, such compensation costs are recognized as compensation expense over the relevant service period. Compensation costs are initially based on the probable outcome of the performance conditions and adjusted for subsequent changes in the estimated or actual outcome each reporting period as necessary. Changes in the estimated or actual outcome of a performance condition are recognized by reflecting a retrospective adjustment to compensation cost in the current period. In 2020, the Ambac UK Board of Directors adopted a long term incentive plan for Ambac UK employees, which includes both performance and time based awards. Compensation costs for all performance based awards are based on the probable outcome of the performance conditions and adjusted for subsequent changes in the estimated or actual outcome each reporting period as
Lessee, Operating Lease, Disclosure [Table Text Block]	Operating Leases A contract contains a lease if it conveys the right to control the use of identified property, plant, or equipment for a period of time in exchange for consideration. Ambac's evaluation of whether certain contracts contain leases requires judgment regarding what party controls the asset and whether the asset is physically distinct. Ambac is the lessee in leases which are classified as operating leases. Ambac recognizes a single lease cost, calculated so that the cost is allocated generally on a straight-line basis over the lease term within operating expenses in the Consolidated Statements of Total Comprehensive Income (Loss). The lease term commences on the earlier of the date when we become legally obligated for the rent payments or the date on which we take possession of the property. For such operating leases, Ambac recognizes a right-of-use ("ROU") asset and a lease liability, initially measured at the present value of the lease payments. The discount rate used to initially measure the ROU assets and lease liabilities reflects the estimated secured borrowing rate of the applicable Ambac subsidiary, which considers the rate of existing or recent debt obligations of the entity. All cash payments are classified within operating activities in the statement of cash flows.
Depreciation and Amortization	Depreciation and AmortizationDepreciation of furniture and fixtures, certain information technology development costs and electronic data processing equipment is charged over the estimated useful lives of the respective assets, ranging from three five
Foreign Currency	Foreign Currency Financial statement accounts expressed in foreign currencies are translated into U.S. dollars in accordance with the Foreign Currency Matters Topic of the ASC. The functional currencies of Ambac's subsidiaries are the local currencies of the country where the respective subsidiaries are based, which are also the primary operating environments in which the subsidiaries operate. Foreign currency translation: Functional currency assets and liabilities of Ambac’s foreign subsidiaries are translated into U.S. dollars using exchange rates in effect at the balance sheet dates and the related translation adjustments, net of deferred taxes, are included as a component of Accumulated Other Comprehensive Income (Loss) in Stockholders' Equity. Functional currency operating results of foreign subsidiaries are translated using average exchange rates. Foreign currency transactions: 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 $11, $(7) and $(1) for the years ended December 31, 2022, 2021 and 2020, respectively. Foreign currency transactions gains/(losses) are primarily the result of remeasuring Ambac UK's assets and liabilities denominated in currencies other than its functional currency, primarily the U.S. dollar and the Euro.
Income Taxes	Income Taxes Ambac files a consolidated U.S. Federal income tax return with its subsidiaries. Ambac and its subsidiaries also file separate or combined income tax returns in various states, local and foreign jurisdictions. Current tax assets and liabilities are recognized for taxes refundable or payable for the current year. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on current and deferred tax assets and liabilities of a change in tax rates is recognized in the period that includes the enactment date. In June 2021, the United Kingdom legislation increasing the tax rate from 19% to 25% was fully enacted. As such, we incorporated the effects of the tax rate increase in our current and deferred tax evaluation for the years ended December 31, 2021 and 2022. The Income Taxes Topic of the ASC requires that companies assess whether valuation allowances should be established against their deferred tax assets based on the consideration of all available evidence using a ‘more likely than not' standard. In making such judgments, significant weight is given to evidence that can be objectively verified. The level of deferred tax asset recognition is influenced by management’s assessment of future profitability, which depends on the existence of sufficient
Net Income Per Share	Net Income Per Share Basic net income per share is computed by dividing net income attributable to common stockholders, including the adjustment to redemption value of the redeemable noncontrolling interest, by the weighted-average number of common shares outstanding and vested restricted stock units (together, "Basic Weighted Average Shares Outstanding"). Diluted net income per share is
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.
Adoption of New Accounting Standards	Adopted Accounting Standards The Company adopted the following accounting standards in 2022: Contracts Assets and Liabilities in a Business Combination In October 2021, the FASB issued ASU 2021-08, Accounting for Contract Asset and Contract Liabilities from Contracts with Customers . The business combination guidance in ASC 805 generally requires a company to recognize and measure the assets and the liabilities it acquires at fair value on the acquisition date. ASC 805 further requires the acquired assets and liabilities to be subsequently measured in accordance with other relevant GAAP standards. ASU 2021-08 creates an exception to the general rule and requires contract assets and liabilities acquired in a business combination to be recognized in accordance with ASC 606 at the acquisition date. The ASU aligns the business combination accounting at the acquisition date with the subsequent accounting for contract assets and liabilities under ASC 606. The ASU is effective for fiscal years beginning after December 15, 2022, with early adoption permitted, including early adoption in an interim period. Ambac early-adopted the ASU on November 1, 2022, and applied it to the acquisitions of All-Trans and Capacity Marine. The adoption did not have a consequential impact on Ambac's financial statements. Reference Rate Reform In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848) - Facilitation of the Effects of Reference Rate Reform on Financial Reporting . The ASU provides companies with optional guidance to ease the potential accounting burden related to transitioning away from reference rates, such as LIBOR, that are expected to be discontinued as a result of initiatives undertaken by various jurisdictions around the world. For example, under current GAAP, contract modifications which change a reference rate are required to be evaluated in determining whether the modifications result in the establishment of new contracts or the continuation of existing contracts. The amendments in this ASU provide optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The ASU can be applied prospectively as of the beginning of the interim period that includes or is subsequent to March 12, 2020, or any date thereafter, but does not apply to contract modifications and other transactions entered into or evaluated after December 31, 2022. In December 2022, the FASB issued ASU 2022-06 which extends the sunset date to December 31, 2024. The ASU was adopted in 2022 for applicable financial instruments and contracts that transitioned to new reference rates and the adoption did not have a consequential impact on Ambac's financial statements. Equity-classified Written Call Options In May 2021, the FASB issued ASU 2021-04, Issuer's Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options . The ASU clarifies and reduces diversity in practice for an issuer's accounting for modifications or exchanges of equity-classified written call options (e.g. warrants) that remain equity-classified after the modification or exchange. The ASU requires an issuer to account for the modification or exchange based on the economic substance of the transaction. For example, if the modification or exchange is related to the issuance of debt or equity, any change in the fair value of the written call option would be accounted for as part of the debt issuance cost in accordance with the debt guidance or equity issuance cost in accordance with the equity guidance, respectively. The ASU was adopted on January 1, 2022 and did not have a consequential impact on Ambac's financial statements. Convertible Instruments and Contracts in an Entity's Own Equity In August 2020, the FASB issued ASU 2020-06, Accounting for Convertible Instruments and Contracts in an Entity's Own Equity . The ASU i) simplifies the accounting for convertible debt and convertible preferred stock by reducing the number of accounting models, and amends certain disclosures, ii) amends and simplifies the derivative scope exception guidance for contracts in an entity's own equity, including share-based compensation, and iii) amends the diluted earnings per share calculations for convertible instruments and contracts in an entity's own equity. The ASU was adopted on January 1, 2022 and did not have a consequential impact on Ambac's financial statements. Future Application of Accounting Standards: There are no material future accounting standards currently being evaluated.

Background and Business Descr_2

Background and Business Description Reorganization Costs (Tables)	12 Months Ended
	Dec. 31, 2022
Reorganizations [Abstract]
RMBS Litigation Settlement Impact on Consolidated Results	The total gain recognized in net income attributable to common stockholders related to entering into the BOA Settlement Agreement and the Nomura Settlement Agreement, including the redemption of the Sitka AAC Note following the BOA Settlement, was as follows: Third Fourth Full Losses and loss benefit (1) $ 319 $ 43 $ 362 Litigation recoveries — 126 126 Net realized gains (losses) on extinguishment of debt — (53) (53) Net investment gains (losses), including impairments — 5 5 Impact to net income attributable to common stockholders $ 319 $ 121 $ 440 (1) Full year 2022 losses and loss benefit relating to R&W recoveries were $123.

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies Supplemental Cash Flow Information (Tables)	12 Months Ended
	Dec. 31, 2022
Schedule of Cash Flow Supplemental Information [Line Items]
Schedule of Supplemental Cash Flow Information [Table Text Block]	Supplemental Disclosure of Cash Flow Information Year Ended December 31, 2022 2021 2020 Cash paid during the period for: Income taxes $ 6 $ 15 $ 11 Interest on long-term debt 283 80 107 Non-cash investing and financing activities: Decrease in long-term debt as a result of surplus notes exchanges — 71 — Securities acquired in transactions related to Puerto Rico restructurings 508 — — Loans acquired through financial guarantee subrogation 20 — — VIE long-term debt issued related to Puerto Rico restructurings 583 — — December 31, 2022 2021 2020 Reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets to the Consolidated Statements of Cash Flow: Cash and cash equivalents $ 31 $ 17 $ 20 Restricted cash 14 5 13 Variable Interest Entity Restricted cash 17 2 2 Total cash, cash equivalents, and restricted cash shown on the Consolidated Statements of Cash Flows 61 23 35
Cash Flow, Supplemental Disclosures [Text Block]	Supplemental information related to leases is as follows: Year Ended December 31, 2022 2021 Cash paid for amounts included in the measurement of operating lease liabilities $ 5 $ 5 Right-of-use assets obtained in exchange for operating lease liabilities (non-cash) — —
Redeemable Noncontrolling Interest	Following is a rollforward of redeemable noncontrolling interest. Years ended December 31, 2022 2021 Beginning balance $ 18 $ 7 Fair value of redeemable noncontrolling interest at acquisition date 5 — Net income attributable to redeemable noncontrolling interest (ASC 810) (1) (1) Adjustment to redemption value (ASC 480 ) (3) 12 Ending Balance $ 20 $ 18

Business Combinations (Tables)

Business Combinations (Tables)	3 Months Ended	12 Months Ended
Business Combinations (Tables)	Dec. 31, 2022	Dec. 31, 2022
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	Fair Value All Trans & Capacity Marine Xchange Cash $ 4 $ 2 Restricted cash 4 4 Intangible assets 16 36 Goodwill 15 46 Other assets 6 8 Total assets acquired $ 45 $ 96 Other liabilities 13 8 Total liabilities assumed 13 8 Less: Redeemable noncontrolling interest 5 7 Total consideration $ 26 $ 81	The following table summarizes the consideration paid for these acquisitions and the estimated fair values of the aggregate assets and liabilities acquired, as well as the fair value of the noncontrolling interest, at the acquisition dates: Fair Value All Trans & Capacity Marine Xchange Cash $ 4 $ 2 Restricted cash 4 4 Intangible assets 16 36 Goodwill 15 46 Other assets 6 8 Total assets acquired $ 45 $ 96 Other liabilities 13 8 Total liabilities assumed 13 8 Less: Redeemable noncontrolling interest 5 7 Total consideration $ 26 $ 81
Schedule of Indefinite-lived Intangible Assets Acquired as Part of Business Combination		The following table sets forth the estimated fair values of identifiable intangible assets acquired and their estimated useful lives as of the date of acquisition. Fair Weighted All Trans & Capacity Marine Distribution relationships $ 15 15.0 Trade name 1 15.0 Total 16 Xchange Distribution relationships $ 33 15.0 Non-compete agreements 1 5.0 Trade name 1 8.0 Total $ 36
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense		The estimated future amortization expense for finite-lived intangible assets is as follows: Amortization Expense Insurance Intangible Asset (1) Other Intangible Assets (1) Total 2023 $ 27 $ 4 $ 31 2024 25 4 29 2025 23 4 27 2026 21 3 25 2027 19 3 23 Thereafter 149 28 178

Investments (Tables)

Investments (Tables)	12 Months Ended
Investments (Tables)	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Summary of Amortized Cost and Estimated Fair Value of Available-for-Sale Investments, Excluding VIE Investments	The amortized cost and estimated fair value of available-for-sale investments, excluding VIE investments, at December 31, 2022 and 2021 were as follows: Amortized Allowance for Credit Losses Gross Gross Estimated December 31, 2022 Fixed maturity securities: Municipal obligations $ 44 $ — $ — $ 2 $ 43 Corporate obligations 659 — 1 63 598 Foreign obligations 85 — — 9 76 U.S. government obligations 68 — — 4 65 Residential mortgage-backed securities 230 — 28 19 238 Commercial mortgage-backed securities 15 — — — 15 Collateralized debt obligations 141 — — 4 137 Other asset-backed securities (1) 227 — 2 5 224 1,469 — 31 106 1,395 Short-term 507 — — — 507 1,977 — 31 106 1,902 Fixed maturity securities pledged as collateral: Short-term 64 — — — 64 64 — — — 64 Total available-for-sale investments $ 2,041 $ — $ 31 $ 106 $ 1,966 December 31, 2021 Fixed maturity securities: Municipal obligations $ 315 — 28 3 340 Corporate obligations 612 — 10 9 613 Foreign obligations 89 — — 2 87 U.S. government obligations 45 — 1 1 45 Residential mortgage-backed securities 182 — 70 — 252 Collateralized debt obligations 128 — — — 128 Other asset-backed securities (1) 234 — 32 — 265 1,605 — 141 16 1,730 Short-term 415 — — — 414 2,020 — 141 16 2,145 Fixed maturity securities pledged as collateral: U.S. government obligations 15 — — — 15 Short-term 105 — — — 105 120 — — — 120 Total available-for-sale investments 2,140 $ — $ 141 $ 16 $ 2,265
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 December 31, 2022, by contractual maturity, were as follows: Amortized Estimated Due in one year or less $ 606 $ 605 Due after one year through five years 456 427 Due after five years through ten years 317 277 Due after ten years 51 43 1,429 1,353 Residential mortgage-backed securities 230 238 Commercial mortgage-backed securities 15 15 Collateralized debt obligations 141 137 Other asset-backed securities 227 224 Total $ 2,041 $ 1,966
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 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 December 31, 2022 and 2021: Less Than 12 Months 12 Months or More Total Fair Value Gross Fair Value Gross Fair Value Gross December 31, 2022 Fixed maturity securities: Municipal obligations $ 21 $ 1 $ 7 $ 1 $ 28 $ 2 Corporate obligations 280 21 279 42 559 63 Foreign obligations 27 2 47 7 73 9 U.S. government obligations 40 3 19 1 58 4 Residential mortgage-backed securities 132 19 — — 132 19 Commercial mortgage-backed securities 3 — — — 3 — Collateralized debt obligations 90 3 36 1 126 4 Other asset-backed securities 198 4 5 1 203 5 791 53 392 53 1,183 106 Short-term 78 — 8 — 86 — Total temporarily impaired securities $ 869 $ 53 $ 400 $ 53 $ 1,269 $ 106 Less Than 12 Months 12 Months or More Total Fair Value Gross Fair Value Gross Fair Value Gross December 31, 2021 Fixed maturity securities: Municipal obligations $ 117 $ 3 $ 2 $ — $ 118 $ 3 Corporate obligations 363 8 17 1 380 9 Foreign obligations 75 2 3 — 78 2 U.S. government obligations 25 — 2 — 27 1 Residential mortgage-backed securities — — 1 — 2 — Collateralized debt obligations 68 — 3 — 71 — Other asset-backed securities 6 — — — 6 — 654 14 28 1 682 16 Short-term 114 — 13 — 128 — 768 14 41 1 810 16 Fixed income securities, pledged as collateral: U.S. government obligations 15 — — — 15 — Total collateralized investments 15 — — — 15 — Total temporarily impaired securities $ 783 $ 14 $ 41 $ 1 $ 825 $ 16
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: Year Ended December 31, 2022 2021 2020 Gross realized gains on securities $ 36 $ 14 $ 38 Gross realized losses on securities (18) (2) (12) Foreign exchange (losses) gains 14 (5) (4) Credit impairments — — — Intent / requirement to sell impairments — — — Net investment gains (losses), including impairments $ 31 $ 7 $ 22
Summary of Net Investment Income	The portion of net unrealized gains (losses) related to securities classified as trading and equity securities, excluding those reported using the equity method, still held at the end of each period is as follows: Year Ended December 31, 2022 2021 2020 Net gains (losses) recognized during the period on trading securities $ (48) $ 23 $ — Less: net gains (losses) recognized during the reporting period on trading securities sold during the period (26) 1 (18) Unrealized gains (losses) recognized during the reporting period on trading securities still held at the reporting date $ (22) $ 22 $ 18
Investment	In addition to these investments, Ambac has unfunded commitments of $53 to private credit and private equity funds at December 31, 2022. Class of Funds December 31, 2022 2021 Redemption Frequency Redemption Notice Period Hedge funds (1) $ 186 $ 216 quarterly or semi-annually 90 days Private credit (4) 84 88 quarterly if permitted 180 days if permitted High yield and leveraged loans (5) 80 78 daily 0 - 30 days Equity market investments (3) (11) 64 98 daily or quarterly 0 - 90 days Investment grade floating rate income (2) 63 107 weekly 0 days Private equity (6) 47 37 quarterly if permitted 90 days if permitted Real estate properties (7) 22 33 quarterly 10 business days Convertible bonds (10)(11) 8 — daily 0 days Emerging markets debt (8) (11) — 24 daily 0 days Insurance-linked investments (9) 1 2 see footnote (9) see footnote (9) Total equity investments in pooled funds $ 556 $ 683 (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 of funds includes investments in high quality floating rate debt securities including ABS and corporate floating rate notes. (3) This class of funds aim to achieve long-term growth through diversified exposure to global equity markets. (4) This class aims to obtain high long-term returns primarily through credit and preferred equity investments with low liquidity and defined term. (5) 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. (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 (8) This class seeks long-term income and growth through investments in the bonds of issuers in emerging markets. (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) This class seeks to generate total return from portfolios focused primarily on convertible securities

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
Fair Value Measurements (Tables)	Dec. 31, 2022
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 December 31, 2022 and 2021, 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. Carrying Total Fair Fair Value Measurements Categorized as: Level 1 Level 2 Level 3 December 31, 2022: Financial assets: Fixed maturity securities: Municipal obligations $ 102 $ 102 $ — $ 102 $ — Corporate obligations 598 598 — 585 12 Foreign obligations 76 76 76 — — U.S. government obligations 65 65 65 — — Residential mortgage-backed securities 238 238 — 238 — Commercial mortgage-backed securities 15 15 — 15 — Collateralized debt obligations 137 137 — 137 — Other asset-backed securities 224 224 — 157 67 Fixed maturity securities, pledged as collateral: Short-term 64 64 64 — — Short term investments 507 507 506 1 — Other investments (1) 568 556 61 — — Cash, cash equivalents and restricted cash 44 44 43 1 — Derivative assets: Interest rate swaps—asset position 27 27 — 1 26 Warrants 1 1 — — 1 Other assets-loans 10 10 — — 10 Variable interest entity assets: Fixed maturity securities: Corporate obligations, fair value option 1,828 1,828 — — 1,828 Fixed maturity securities: Municipal obligation, trading 43 43 — 43 — Fixed maturity securities: Municipal obligations, available-for-sale 96 96 — 96 — Restricted cash 17 17 17 — — Loans 1,829 1,829 — — 1,829 Derivative assets: Interest rate swaps—asset position 190 190 — 190 — Derivative assets: Currency swaps—asset position 49 49 — 49 — Total financial assets $ 6,537 $ 6,525 $ 833 $ 1,425 $ 3,772 Financial liabilities: Long term debt, including accrued interest $ 1,065 $ 878 $ — $ 864 $ 14 Derivative liabilities: Interest rate swaps—liability position 38 38 — 38 — Liabilities for net financial guarantees written (2) 159 476 — — 476 Variable interest entity liabilities: Long-term debt (includes $2,788 at fair value) 3,107 3,145 — 2,992 154 Derivative liabilities: Interest rate swaps—liability position 1,048 1,048 — 1,048 — Total financial liabilities $ 5,418 $ 5,586 $ — $ 4,942 $ 644 Carrying Total Fair Fair Value Measurements Categorized as: Level 1 Level 2 Level 3 December 31, 2021: Financial assets: Fixed maturity securities: Municipal obligations $ 340 $ 340 $ — $ 340 $ — Corporate obligations 613 613 1 600 12 Foreign obligations 87 87 87 — — U.S. government obligations 45 45 45 — — Residential mortgage-backed securities 252 252 — 252 — Collateralized debt obligations 128 128 — 128 — Other asset-backed securities 265 265 — 187 79 Fixed maturity securities, pledged as collateral: U.S. government obligations 15 15 15 — — Short-term 105 105 105 — — Short term investments 414 414 369 46 — Other investments (1) 690 683 106 — — Cash, cash equivalents and restricted cash 21 21 21 1 — Derivative assets: Interest rate swaps—asset position 76 76 — 5 71 Other assets-loans 3 3 — — 3 Variable interest entity assets: Fixed maturity securities: Corporate obligations, fair value option 3,320 3,320 — — 3,320 Fixed maturity securities: Municipal obligations, available-for-sale 136 136 — 136 — Restricted cash 2 2 2 — — Loans 2,718 2,718 — — 2,718 Derivative assets; Currency swaps-asset position 38 38 — 38 — Total financial assets $ 9,268 $ 9,261 $ 750 $ 1,732 $ 6,202 Financial liabilities: Long term debt, including accrued interest $ 2,806 $ 2,598 $ — $ 2,575 $ 22 Derivative liabilities: Interest rate swaps—liability position 94 94 — 94 — Liabilities for net financial guarantees written (2) (866) (112) — — (112) Variable interest entity liabilities: Long-term debt (includes $4,056 at fair value) 4,216 4,255 — 4,086 169 Derivative liabilities: Interest rate swaps—liability position 1,940 1,940 — 1,940 — Total financial liabilities $ 8,190 $ 8,775 — 8,695 79 (1) Excluded from the fair value measurement categories in the table above are investment funds of $494 and $577 as of December 31, 2022 and 2021, respectively, which are measured using NAV as a practical expedient. Also excluded from the fair value measurements in the table above are equity securities with a carrying value of $12 and $8 as of December 31, 2022 and 2021, 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 adjustment 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 2022, 2021 and 2020. 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 and Liabilities Year ended December 31, 2022 Investments (1) Other Derivatives Investments Loans Total Balance, beginning of period $ 91 $ — $ 70 $ 3,320 $ 2,718 $ 6,199 Total gains/(losses) realized and unrealized: Included in earnings 1 — (38) (789) (333) (1,160) Included in other comprehensive income (12) — — (353) (279) (644) Purchases — — — — — — Issuances — — — — — — Sales — — — — — — Settlements (1) — (6) (349) (278) (633) Balance, end of period $ 79 $ — $ 26 $ 1,828 $ 1,829 $ 3,762 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 $ — $ (38) $ (789) $ (333) $ (1,160) 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 $ (12) $ — $ — $ (353) $ (279) $ (644) Level-3 Financial Assets and Liabilities Accounted for at Fair Value VIE Assets and Liabilities Year Ended December 31, 2021 Investments (1) Other Assets (2) Derivatives Investments Loans Total Balance, beginning of period $ 78 $ 1 $ 84 $ 3,215 $ 2,998 $ 6,376 Total gains/(losses) realized and unrealized: Included in earnings 1 — (6) 176 59 230 Included in other comprehensive income 1 — — (32) (26) (58) Purchases 13 — — — — 13 Issuances — — — — — — Sales — — — — — — Settlements (2) (1) (8) (38) (313) (362) Balance, end of period $ 91 $ — $ 70 $ 3,320 $ 2,718 $ 6,199 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) $ — $ (6) $ 176 $ 59 $ 227 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 $ (1) $ — $ — $ (32) $ (26) $ (59) Level-3 Financial Assets and Liabilities Accounted for at Fair Value VIE Assets and Liabilities Year Ended December 31, 2020 Investments (1) Other Assets (2) Derivatives Investments Loans Total Balance, beginning of period $ 72 $ 3 $ 66 $ 2,957 $ 3,108 $ 6,207 Total gains/(losses) realized and unrealized: Included in earnings 1 (2) 25 183 98 306 Included in other comprehensive income 6 — — 109 83 198 Purchases — — — — — — Issuances — — — — — — Sales — — — — — — Settlements (1) — (7) (35) (290) (334) Balance, end of period $ 78 $ 1 $ 84 $ 3,215 $ 2,998 $ 6,376 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 $ (2) $ 25 $ 183 $ 98 $ 305 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 $ 6 $ — $ — $ 109 $ 83 $ 198 (1) Investments classified as Level 3 consist of a one other asset-backed security and two convertible notes acquired in 2021. (2) Other assets carried at fair value and classified as Level 3 relate to an equity interest in an Ambac sponsored VIE liquidated in 2021.
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: Net Investment Income Net Gains Income (Loss) on Variable Interest Entities Other Year Ended December 31, 2022 Total gains (losses) included in earnings for the period $ 1 $ (38) $ (1,123) $ — Changes in unrealized gains (losses) relating to financial instruments still held at the reporting date 1 (39) (1,123) — Year Ended December 31, 2021 Total gains (losses) included in earnings for the period $ 1 $ (6) $ 235 $ — Changes in unrealized gains (losses) relating to financial instruments still held at the reporting date 1 (6) 235 — Year Ended December 31, 2020 Total gains (losses) included in earnings for the period $ 1 $ 25 $ 281 $ (2) Changes in unrealized gains (losses) relating to financial instruments still held at the reporting date — 25 281 (2)

Financial Guarantees in Force_2

Financial Guarantees in Force (Tables)	12 Months Ended
Financial Guarantees in Force (Tables)	Dec. 31, 2022
Guarantees [Abstract]
Schedule of Financial Guarantee Insurance In Force By Bond Type	As of December 31, 2022 and 2021, the legacy financial guarantee portfolio consisted of the types of guaranteed bonds as shown in the following table: Net Par Outstanding December 31, (1) 2022 2021 Public Finance: Housing revenue (2) $ 5,491 $ 5,610 Lease and tax-backed revenue 1,979 3,196 General obligation 1,301 1,612 Other 1,776 1,942 Total Public Finance 10,547 12,360 Structured Finance: Mortgage-backed and home equity 1,930 2,724 Investor-owned utilities 1,103 1,556 Other 579 624 Total Structured Finance 3,612 4,904 International Finance: Sovereign/sub-sovereign 4,077 5,141 Investor-owned and public utilities 2,583 3,283 Asset-backed and other 1,083 1,276 Transportation 711 1,056 Total International Finance 8,454 10,756 Total $ 22,613 $ 28,020 (1) Net Par Outstanding includes 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. (2) Includes $5,400 and $5,490 of Military Housing net par at December 31, 2022 and 2021, respectively.
Schedule of International Financial Guarantee Insurance In Force Portfolio By Location Of Risk	As of December 31, 2022 and 2021, the financial guaranteed portfolio by location of risk was as outlined in the table below: Net Par Outstanding December 31, 2022 2021 United States $ 14,159 $ 17,264 United Kingdom 7,223 9,255 Italy 644 718 Austria 310 343 Australia 259 203 France 14 219 Other international 4 18 Total $ 22,613 $ 28,020

Financial Guarantee Insurance_2

Financial Guarantee Insurance Contracts (Tables)	12 Months Ended
Financial Guarantee Insurance Contracts (Tables)	Dec. 31, 2022
Insurance [Line Items]
Effect of Reinsurance on Premiums Written and Earned	The effect of reinsurance on premiums written and earned was as follows: Year Ended Direct Assumed Ceded Net 2022: Written $ 127 $ — $ 104 $ 23 Earned 126 — 69 56 2021: Written $ 2 $ — $ 35 $ (33) Earned 62 — 15 47 2020: Written $ (1) $ — $ (1) $ — Earned 65 1 12 54
Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block]	The following table summarizes net premiums earned by location of risk: Year Ended December 31, 2022 2021 2020 United States 41 $ 27 $ 32 United Kingdom 13 14 24 Other international 3 6 (2) Total 56 $ 47 $ 54 Premium Receivables, including credit impairments Premium receivables at December 31, 2022 and 2021 were $269 and $323, respectively. Management evaluates premium receivables for expected credit losses ("credit impairment") in accordance with the CECL standard adopted January 1, 2020, which is further described in Note 2. Basis of Presentation and Significant Accounting Policies . The key indicator management uses to assess the credit quality of legacy financial guarantee premium receivables is Ambac's internal risk classifications for the insured obligation determined by the Risk Management Group. Below is the amortized cost basis of financial guarantee premium receivables by risk classification code and asset class as of December 31, 2022 and 2021: Surveillance Categories as of December 31, 2022 Type of Guaranteed Bond I IA II III IV Total Public Finance: Housing revenue $ 140 $ 3 $ 5 $ — $ — $ 148 Other 2 — — — — 2 Total Public Finance 142 3 5 — — 150 Structured Finance: Mortgage-backed and home equity — — — — 11 11 Student loan 1 1 — 7 — 8 Structured insurance — — — — — — Other 4 — — — — 4 Total Structured Finance 5 1 — 7 11 24 International: Sovereign/sub-sovereign 49 7 — 9 — 64 Investor-owned and public utilities 18 — — — — 18 Other 2 — — — — 2 Total International 70 7 — 9 — 85 Total (1) (2) $ 217 $ 10 $ 5 $ 16 $ 11 $ 259 Surveillance Categories as of December 31, 2021 Type of Guaranteed Bond I IA II III IV Total Public Finance: Housing revenue $ 149 $ 3 $ 5 $ — $ — $ 157 Other 2 — — — — 2 Total Public Finance 151 3 5 — — 159 Structured Finance: Mortgage-backed and home equity 1 — 1 2 12 16 Student loan 1 1 — 9 — 12 Structured insurance 10 — — — — 10 Other 7 — — — — 7 Total Structured Finance 19 1 1 12 12 45 International: Sovereign/sub-sovereign 74 8 — 11 — 93 Investor-owned and public utilities 28 — — — — 28 Other 5 — — — — 5 Total International 107 8 — 11 — 125 Total (2) $ 277 $ 12 $ 6 $ 22 $ 12 $ 329 (1) Excludes specialty property and casualty premium receivables of $16 and $2 at December 31, 2022 and 2021, respectively. (2) The underwriting origination dates for all policies included are greater than five years prior to the current reporting date.
Summarized Future Gross Undiscounted Premiums Expected to be Collected and Future Expected Premiums Earned, Net of Reinsurance	The following table summarizes the future gross undiscounted premiums to be collected and future premiums earned, net of reinsurance at December 31, 2022: Future Premiums Collected (1) Future to be Earned Net of (2) Three months ended: March 31, 2023 $ 8 $ 5 June 30, 2023 7 5 September 30, 2023 7 5 December 31, 2023 5 5 Twelve months ended: December 31, 2024 26 19 December 31, 2025 25 18 December 31, 2026 24 18 December 31, 2027 23 17 Five years ended: December 31, 2032 95 70 December 31, 2037 59 42 December 31, 2042 27 17 December 31, 2047 13 8 December 31, 2052 4 2 December 31, 2057 — — Total $ 322 $ 231 (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 . 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.
Schedule of Loss And Loss Expense Reserves And Subrogation Recoverable Table	Below are the components of the loss and loss adjustment expense reserves and the subrogation recoverable asset at December 31, 2022 and 2021: Legacy Financial Guarantee Specialty Property and Casualty Present Value of Expected Balance Sheet Line Item Gross Loss and Claims and Recoveries Unearned Gross Loss and December 31, 2022: Loss and loss adjustment expense reserves $ 90 $ 787 $ (44) $ (28) $ 805 Subrogation recoverable — 5 (276) — (271) Totals $ 90 $ 791 $ (319) $ (28) $ 534 December 31, 2021: Loss and loss adjustment expense reserves $ 32 $ 1,749 $ (155) $ (56) $ 1,570 Subrogation recoverable — 88 (2,180) — (2,092) Totals $ 32 $ 1,837 $ (2,335) $ (56) $ (522)
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. Year Ended December 31, 2022 2021 2020 Beginning gross loss and loss adjustment expense reserves $ (522) $ (397) $ (482) Reinsurance recoverable 55 33 26 Beginning balance of net loss and loss adjustment expense reserves (578) (430) (508) Losses and loss expenses (benefit) incurred: Current year 4 — 15 Prior years (401) (89) 210 Total (1)(2) (397) (88) 225 Loss and loss adjustment expenses (recovered) paid: Current year 7 — 1 Prior years (1,867) 59 148 Total (1,860) 59 149 Foreign exchange effect (2) — 2 Ending net loss and loss adjustment expense reserves 883 (578) (430) Impact of VIE consolidation (3) (464) — — Reinsurance recoverable (4) 115 55 33 Ending gross loss and loss adjustment expense reserves 534 (522) (397) (1) Total losses and loss expenses (benefit) includes $(41), $5 and $(7) for the years ended December 31, 2022, 2021 and 2020, respectively, related to ceded reinsurance. (2) Ambac records the impact of estimated recoveries related to securitized loans in RMBS transactions that breached certain representations and warranties ("R&W's") by transaction sponsors within losses and loss expenses (benefit) for the Legacy Financial Guarantee segment. The losses and loss expense (benefit) incurred associated with changes in estimated R&W's for the year ended December 31, 2022, 2021 and 2020 was $(123), $20 and $(23), respectively. Refer to Note 1. Background and Business Description to the Consolidated Financial Statements in this Annual Report on Form 10-K for details of the RMBS litigation settlements reached in October and December 2022. (3) In connection with the Puerto Rico restructuring, three new trusts were established for the year ended December 31, 2022. These trusts were consolidated by Ambac as further discussed in Note 12. Variable Interest Entities. (4) Represents reinsurance recoverable on future loss and loss adjustment expenses. Additionally, the Balance Sheet line "Reinsurance recoverable on paid and unpaid losses" includes reinsurance recoverables (payables) of $0, $0 and $0 as of December 31, 2022, 2021 and 2020, respectively, related to previously presented loss and loss adjustment 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 adjustment expense reserves or subrogation recoverable at December 31, 2022 and 2021, 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 December 31, 2022 and 2021 was 3.9% and 1.2%, respectively. 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 13 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 adjustment expense reserves $ (10) $ (2) $ 32 $ 252 $ 137 $ 34 $ 444 Reinsurance recoverable reported on $ 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 adjustment expenses and $0 related to presented loss and loss adjustment expenses and subrogation. Surveillance Categories as of December 31, 2021 I IA II III IV V Total Number of policies 34 15 7 14 130 5 205 Remaining weighted-average contract period (in years) (1) 9 12 14 15 13 7 14 Gross insured contractual payments outstanding: Principal $ 904 $ 840 $ 459 $ 1,300 $ 2,759 $ 40 $ 6,302 Interest 589 612 308 169 1,284 22 2,984 Total $ 1,493 $ 1,452 $ 767 $ 1,469 $ 4,043 $ 62 $ 9,286 Gross undiscounted claim liability $ 5 $ 16 $ 45 $ 544 $ 1,423 $ 62 $ 2,095 Discount, gross claim liability — (1) (3) (109) (185) (4) (303) Gross claim liability before all subrogation and before reinsurance $ 5 $ 15 $ 42 $ 435 $ 1,238 $ 57 $ 1,792 Less: Gross RMBS subrogation (2) $ — $ — $ — $ — $ (1,737) $ — $ (1,737) Discount, RMBS subrogation — — — — 7 — 7 Discounted RMBS subrogation, before reinsurance — — — — (1,730) — (1,730) Less: Gross other subrogation (3) — (5) — (33) (583) (12) (633) Discount, other subrogation — — — 2 24 2 28 Discounted other subrogation, before reinsurance — (5) — (31) (559) (10) (605) Gross claim liability, net of all subrogation and discounts, before reinsurance $ 5 $ 10 $ 42 $ 404 $ (1,051) $ 47 $ (543) Less: Unearned premium revenue $ (3) $ (10) $ (5) $ (14) $ (24) $ (1) $ (56) Plus: Loss expense reserves 1 — — 4 40 — 45 Gross loss and loss adjustment expense reserves $ 3 $ 1 $ 38 $ 394 $ (1,036) $ 46 $ (554) Reinsurance recoverable reported on $ 1 $ 1 $ 10 $ 22 $ (11) $ — $ 23 (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 $24 related to future loss and loss adjustment expenses and $0 related to presented loss and loss adjustment expenses and subrogation.
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	ntangible asset and accumulated amortization are included in the Consolidated Balance Sheets, as shown below. December 31, 2022 2021 Finite-lived Intangible Assets: Insurance intangible: Gross carrying value $ 1,247 $ 1,278 Accumulated amortization 981 958 Net insurance intangible asset 266 320 Other intangibles: Gross Carrying value 52 36 Accumulated amortization 6 3 Net other intangible assets 47 33 Total finite-lived intangible assets $ 312 $ 353 Indefinite-lived Intangible Assets: Insurance licenses $ 14 $ 9 Total intangible assets $ 326 $ 362
Premium Receivable, Allowance for Credit Loss	Below is a rollforward of the premium receivable allowance for credit losses as of December 31, 2022 and 2021: Year Ended December 31, 2022 2021 Beginning balance $ 9 $ 17 Current period provision (benefit) (4) (6) Write-offs of the allowance — (2) Recoveries of previously written-off amounts — — Ending balance $ 5 $ 9
Schedule of Financial Guarantee Insurance In Force By Bond Type	As of December 31, 2022 and 2021, the legacy financial guarantee portfolio consisted of the types of guaranteed bonds as shown in the following table: Net Par Outstanding December 31, (1) 2022 2021 Public Finance: Housing revenue (2) $ 5,491 $ 5,610 Lease and tax-backed revenue 1,979 3,196 General obligation 1,301 1,612 Other 1,776 1,942 Total Public Finance 10,547 12,360 Structured Finance: Mortgage-backed and home equity 1,930 2,724 Investor-owned utilities 1,103 1,556 Other 579 624 Total Structured Finance 3,612 4,904 International Finance: Sovereign/sub-sovereign 4,077 5,141 Investor-owned and public utilities 2,583 3,283 Asset-backed and other 1,083 1,276 Transportation 711 1,056 Total International Finance 8,454 10,756 Total $ 22,613 $ 28,020 (1) Net Par Outstanding includes 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. (2) Includes $5,400 and $5,490 of Military Housing net par at December 31, 2022 and 2021, respectively.
Premiums Receivable for Financial Guarantees	Below is the gross premium receivable roll-forward (direct contracts), net of the allowance for credit losses, for the affected periods: Year Ended 2022 2021 2020 Beginning premium receivable $ 320 $ 370 $ 416 Adjustment to initially apply ASU 2016-13 — — (3) Premium receipts (36) (35) (46) Adjustments for changes in expected and contractual cash flows for contracts (1) (31) (27) (6) Accretion of premium receivable discount for contracts 8 8 9 Changes to allowance for credit losses 4 8 (4) Other adjustments (including foreign exchange) (2) (12) (4) 5 Ending premium $ 254 $ 320 $ 370 (1) Adjustments for changes in expected and contractual cash flows are primarily due to higher discount rates and reductions in insured exposure as a result of early policy terminations and unscheduled principal paydowns . (2) Includes foreign exchange gains/(losses) of ($13), ($2) and $4 for 2022, 2021,and 2020 respectively. (3) Premium receivable includes premiums to be received in foreign denominated currencies most notably in British Pounds and Euros.
Reinsurance Recoverable, Credit Quality Indicator	The following table sets forth our three most significant reinsurers by amount of reinsurance recoverable as of December 31, 2022. Reinsurers Type of Insurance Rating (1) Reinsurance Recoverable (2) Unsecured Recoverable (3) QBE Insurance Corporation Specialty P&C A $ 41 $ 41 Assured Guaranty Re Ltd. Financial AA 30 — General Reinsurance Company Specialty P&C A++ 25 11 All other reinsurers 18 7 Total recoverables $ 115 $ 60 (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)	12 Months Ended
Derivative Instruments (Tables)	Dec. 31, 2022
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]	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 December 31, 2022 and 2021. Gross Gross Net Amounts Gross Amount Net Amount December 31, 2022: Derivative Assets: Interest rate swaps $ 27 $ — $ 27 $ — $ 27 Warrants 1 — 1 — 1 Total non-VIE derivative assets $ 28 $ — $ 27 $ — $ 27 Derivative Liabilities: Interest rate swaps 38 — 38 38 — Total non-VIE derivative liabilities $ 38 $ — $ 38 $ 38 $ — Variable Interest Entities Derivative Assets: Interest rate swaps $ 190 $ — $ 190 $ — $ 190 Currency swaps 49 — 49 — 49 Total VIE derivative assets $ 239 $ — $ 239 $ — $ 239 Variable Interest Entities Derivative Liabilities: Interest rate swaps $ 1,048 $ — $ 1,048 $ — $ 1,048 Total VIE derivative liabilities $ 1,048 $ — $ 1,048 $ — $ 1,048 December 31, 2021: Derivative Assets: Interest rate swaps $ 76 $ — $ 76 $ — $ 76 Total non-VIE derivative assets $ 76 $ — $ 76 $ — $ 76 Derivative Liabilities: Credit derivatives $ — $ — $ — $ — $ — Interest rate swaps 94 — 94 93 1 Total non-VIE derivative liabilities $ 95 $ — $ 95 $ 93 $ 2 Variable Interest Entities Derivative Assets: Currency swaps $ 38 $ — $ 38 $ — $ 38 Total VIE derivative assets $ 38 $ — $ 38 $ — $ 38 Variable Interest Entities Derivative Liabilities: Interest rate swaps $ 1,940 $ — $ 1,940 $ — $ 1,940 Total VIE derivative liabilities $ 1,940 $ — $ 1,940 $ — $ 1,940
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 Consolidated Statements of Total Comprehensive Income (Loss) for the years ended December 31, 2022, 2021 and 2020: Location of Gain (Loss) Recognized Amount of Gain (Loss) Recognized in Consolidated Statement of Total Comprehensive Income (Loss) – 2022 2021 2020 Non-VIE derivatives: Credit derivatives Net gains (losses) on derivative contracts $ — $ — $ — Interest rate swaps Net gains (losses) on derivative contracts 65 13 (9) Warrants Net gains (losses) on derivative contracts 1 — — Futures contracts Net gains (losses) on derivative contracts 62 9 (41) Total Non-VIE derivatives 129 22 (50) Variable Interest Entities: Currency swaps Income (loss) on variable interest entities 24 2 (6) Interest rate swaps Income (loss) on variable interest entities 541 (152) (138) Total Variable Interest Entities 565 (150) (144) Total derivative contracts $ 694 $ (128) $ (193)
Summary of Notional Amounts of AFS's Trading Derivative Products	As of December 31, 2022 and 2021, the notional amounts of AFS's derivatives are as follows: Notional - December 31, Type of Derivative 2022 2021 Interest rate swaps—pay-fixed/receive-variable $ 989 $ 1,275 US Treasury futures contracts—short — 470 Interest rate swaps—receive-fixed/pay-variable 337 185 Other Derivatives: The principal notional outstanding for credit derivative contracts was $0 and $201 as of December 31, 2022 and December 31, 2021, respectively.
Variable Interest Entity [Member]
Summary of Notional Amounts of AFS's Trading Derivative Products	The notional for VIE derivatives outstanding as of December 31, 2022 and 2021, were as follows: Notional - December 31, Type of VIE Derivative 2022 2021 Interest rate swaps—receive-fixed/pay-variable $ 1,573 $ 1,221 Interest rate swaps—pay-fixed/receive-variable 887 1,069 Currency swaps 176 272

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
Intangible Assets (Tables)	Dec. 31, 2022
Statement of Financial Position [Abstract]
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	ntangible asset and accumulated amortization are included in the Consolidated Balance Sheets, as shown below. December 31, 2022 2021 Finite-lived Intangible Assets: Insurance intangible: Gross carrying value $ 1,247 $ 1,278 Accumulated amortization 981 958 Net insurance intangible asset 266 320 Other intangibles: Gross Carrying value 52 36 Accumulated amortization 6 3 Net other intangible assets 47 33 Total finite-lived intangible assets $ 312 $ 353 Indefinite-lived Intangible Assets: Insurance licenses $ 14 $ 9 Total intangible assets $ 326 $ 362
Finite-lived Intangible Assets Amortization Expense	Amortization expense is included in the Consolidated Statements of Total Comprehensive Income (Loss), as shown below. Year ended December 31, 2022 2021 2020 Insurance intangible $ 44 52 $ 57 Other intangibles 3 3 — Total $ 47 $ 55 $ 57
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The estimated future amortization expense for finite-lived intangible assets is as follows: Amortization Expense Insurance Intangible Asset (1) Other Intangible Assets (1) Total 2023 $ 27 $ 4 $ 31 2024 25 4 29 2025 23 4 27 2026 21 3 25 2027 19 3 23 Thereafter 149 28 178
Schedule of Goodwill	The following table presents the Company's goodwill. December 31, 2022 2021 Beginning balance $ 46 $ 46 Business acquisitions 15 — Impairments — — Ending balance $ 61 $ 46

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	12 Months Ended
Variable Interest Entities (Tables)	Dec. 31, 2022
Variable Interest Entity Not Primary Beneficiary Table [Line Items]
Schedule of Variable Interest Entities Assets and Liabilities [Table Text Block]	The following schedule details the components of Income (loss) on variable interest entities for the affected periods: Year ended December 31, 2022 2021 2020 Net change in fair value of VIE assets and liabilities reported under the fair value option $ — $ 4 $ (1) Less: Credit risk changes of fair value option long-term debt reported through other comprehensive income (loss) (1) 1 (1) Net change in fair value of VIE assets and liabilities reported in earnings under the fair value option (1) 5 (3) Investment income (loss) (4) 6 7 Net realized investment gains (losses) on available-for-sale securities 2 2 8 Interest expense on long-term debt carried at par less unamortized cost (12) (6) (6) Other expenses (1) (1) — Gain (loss) from consolidating VIEs 37 — — Income (loss) on variable interest entities $ 21 $ 7 $ 5
Variable Interest Entity Not Primary Beneficiary Table [Table Text Block]	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 December 31, 2022 and 2021: Carrying Value of Assets and Liabilities Maximum (1) Insurance (2) Insurance (3) Net Derivative (Liabilities) (4) December 31, 2022: Global structured finance: Mortgage-backed—residential $ 2,559 $ 266 $ 400 $ — Other consumer asset-backed 652 6 225 — Other 430 2 2 1 Total global structured finance 3,642 274 628 1 Global public finance 17,997 216 212 — Total $ 21,639 $ 490 $ 840 $ 1 December 31, 2021: Global structured finance: Mortgage-backed—residential $ 3,265 $ 1,929 $ 521 $ — Other consumer asset-backed 788 17 234 — Other 826 3 10 5 Total global structured finance 4,879 1,949 765 5 Global public finance 20,233 246 257 — Total $ 25,112 $ 2,195 $ 1,023 $ 5 (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 adjustment 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 credit derivative contracts and interest rate swaps on Ambac’s Consolidated Balance Sheets.

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
Long-Term Debt (Tables)	Dec. 31, 2022
Debt Instrument [Line Items]
Schedule of Maturities of Long-term Debt [Table Text Block]	Aggregated annual maturities of non-VIE long-term debt obligations (based on scheduled maturity dates as further discussed below) are as follows: 2023 $ 665 (1), (2) 2024 — 2025 — 2026 — 2027 — Thereafter 41 Total $ 706
Schedule of Long-term Debt Instruments	Long-term debt outstanding, excluding VIE long-term debt, was as follows: December 31, 2022 2021 Par Value Unamortized Discount Carrying Value Par Value Unamortized Discount Carrying Value Ambac Assurance: 5.1% Surplus Notes $ 519 $ (42) $ 477 $ 785 $ (56) $ 729 Sitka AAC Note — — $ — 1,175 (21) 1,154 Tier 2 Notes 146 — 146 333 — 333 Ambac UK Debt 41 (25) 16 41 (26) 15 Long-term debt $ 706 $ (67) $ 639 $ 2,334 $ (104) $ 2,230

Revenue from Contract with Cu_2

Revenue from Contract with Customer (Tables)	12 Months Ended
Revenue from Contract with Customer (Tables)	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table presents the revenues recognized in accordance with the Revenue from Contracts with Customers Topic of the ASC disaggregated by policy type for the year ended December 31, 2022 and 2021: Year ended December 31, 2022 2021 Employer stop loss $ 9 $ 8 Affinity products 19 18 Commercial Auto, Marine and Other 3 — Total 31 $ 26
Contract with Customer, Contract Asset, Contract Liability, and Receivable	The balances of contract assets and contract liabilities with customers were as follows: December 31, 2022 2021 Premiums and commissions receivable $ 7 $ 2 Contract assets 5 4 Contract liabilities 1 1

Comprehensive Income (Tables)

Comprehensive Income (Tables)	12 Months Ended
Comprehensive Income (Tables)	Dec. 31, 2022
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: Unrealized Gains (1) Amortization of (1) Gain (Loss) on (1) Credit Risk Changes of Fair Value Option Liabilities (1) (2) Total Year Ended December 31, 2022: Beginning Balance $ 154 $ 4 $ (100) $ (1) $ 58 Other comprehensive income (loss) before reclassifications (211) — (85) — (296) Amounts reclassified from accumulated other comprehensive income (loss) (14) (1) — — (15) Net current period other comprehensive income (loss) (225) (1) (85) — (310) Balance at December 31, 2022 $ (71) $ 3 $ (184) $ (1) $ (253) Year ended December 31, 2021: Beginning Balance $ 166 $ 5 $ (92) $ — $ 79 Other comprehensive income before reclassifications (5) — (8) — (13) Amounts reclassified from accumulated other comprehensive income (7) (1) — (1) (9) Net current period other comprehensive income (loss) (12) (1) (8) (1) (21) Balance at December 31, 2021 $ 154 $ 4 $ (100) $ (1) $ 58 (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 Other Amount Reclassified from Accumulated Affected Line Item in the Year Ended December 31, 2022 2021 Unrealized Gains (Losses) on Available-for-Sale Securities (1) $ (17) $ (7) Net realized investment gains (losses) 3 (1) Provision for income taxes $ (14) $ (7) Net of tax and noncontrolling interest Amortization of Postretirement Benefit Prior service cost $ (1) $ (1) Other income Actuarial gains (losses) — — Other income (1) (1) Total before tax — — Provision for income taxes $ (1) $ (1) Net of tax and noncontrolling interest Credit Risk Changes of Fair Value Option Liabilities $ — $ (1) Credit risk changes of fair value option liabilities — — Provision for income taxes — (1) Net of tax and noncontrolling interest Total reclassifications for the period $ (15) $ (9) Net of tax and noncontrolling interest (1) Net unrealized investment gains (losses) on available for sale securities are included in Ambac's Consolidated Statements of Comprehensive Income as a component of Accumulated Other Comprehensive Income. Changes in these amounts include reclassification adjustments to exclude from "Other comprehensive income (loss)" those items that are included as part of "Net income" for a period that has been part of "Other comprehensive income (loss)" in earlier periods.

Net Income Per Share (Tables)

Net Income Per Share (Tables)	12 Months Ended
Net Income Per Share (Tables)	Dec. 31, 2022
Earnings Per Share [Abstract]
Reconciliation of Common Shares Used for Basic and Diluted Earnings Per Share	The following table provides a reconciliation of the common shares used for basic net income per share to the diluted shares used for diluted net income per share: Year Ended December 31, 2022 2021 2020 Basic weighted average shares outstanding 45,719,906 46,535,001 46,147,062 Effect of potential dilutive shares (1) : Warrants — — — Stock options — — — Restricted stock units 144,194 — — Performance stock units (2) 550,730 — — Diluted weighted average shares outstanding 46,414,830 46,535,001 46,147,062 Anti-dilutive shares excluded from the above reconciliation Warrants 4,877,617 4,877,653 4,877,754 Stock options — — 16,121 Restricted stock units 177,119 475,333 302,145 Performance stock units (2) — 700,915 1,002,501 (1) For the years ended years ended December 31, 2021 and 2020, Ambac had a net loss and accordingly excluded all potentially dilutive securities from the determination of diluted loss per share as their impact was anti-dilutive. (2) Performance stock units are reflected based on the performance metrics through the balance sheet date. Vesting of these units is contingent upon meeting certain performance metrics. Although a portion of these performance metrics have been achieved as of the respective period end, it is possible that awards may no longer meet the metric at the end of the performance period.
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: Year ended December 31, 2022 2021 2020 Net income (loss) attributable to common stockholders $ 522 $ (17) $ (437) Adjustment to redemption value (ASC 480) 3 (12) — Numerator of basic and diluted EPS $ 525 $ (28) $ (437) Per Share: Basic 11.48 $ (0.61) $ (9.47) Diluted 11.31 $ (0.61) $ (9.47)

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2022
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
Significant Portions of Deferred Tax Liabilities and Deferred Tax Assets	The tax effects of temporary differences that give rise to significant portions of the deferred tax liabilities and deferred tax assets at December 31, 2022 and 2021, are presented below: December 31, 2022 2021 Deferred tax liabilities: Insurance intangible $ 56 $ 67 Unearned premiums and credit fees 24 32 Investments — 14 Variable interest entities 4 15 Other 1 6 Total deferred tax liabilities 85 134 Deferred tax assets: Net operating loss carryforward 725 736 Interest expense carryforward 66 50 Investments 6 — Loss reserves 38 180 State capital loss carryforward 8 7 Debentures 15 7 Compensation 6 8 Other 4 4 Subtotal deferred tax assets 867 993 Valuation allowance 796 886 Total deferred tax assets 70 106 Net deferred tax liability $ 15 $ 28
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: Year Ended December 31, 2022 2021 2020 U.S. $ 511 $ (32) $ (441) Foreign 13 34 1 Total $ 525 $ 2 $ (440)
Schedule of Components of Income Tax Expense (Benefit)	The components of the provision (benefit) for income taxes were as follows: Year Ended December 31, 2022 2021 2020 Current taxes U.S. state and local $ — $ 2 $ — Foreign 7 10 8 Total current taxes 6 12 8 Deferred taxes Foreign (4) 6 (10) Total deferred taxes $ (4) $ 6 $ (10) Provision for income taxes $ 2 $ 18 $ (3)
Schedule Of Income Taxes Charged Credited Directly To Equity	The total effect of income taxes on net income and stockholders’ equity for the years ended December 31, 2022, 2021 and 2020 is as follows: Year Ended December 31, 2022 2021 2020 Total income taxes charged to net income $ 2 $ 18 $ (3) Income taxes charged (credited) to stockholders’ equity: Unrealized gains (losses) on investment securities, including foreign exchange (47) (3) 3 Change in retirement benefits — — — Credit Risk Changes to Fair Value Options — — — Valuation allowance to equity 41 1 (3) Total charged to stockholders’ equity: (6) (2) 1 Total effect of income taxes $ (4) $ 16 $ (1)
Schedule of Effective Income Tax Rate Reconciliation	Year Ended December 31, 2022 2021 2020 Total income taxes charged to net income $ 2 $ 18 $ (3) Income taxes charged (credited) to stockholders’ equity: Unrealized gains (losses) on investment securities, including foreign exchange (47) (3) 3 Change in retirement benefits — — — Credit Risk Changes to Fair Value Options — — — Valuation allowance to equity 41 1 (3) Total charged to stockholders’ equity: (6) (2) 1 Total effect of income taxes $ (4) $ 16 $ (1) Reconciliation of U.S. Federal Statutory Income Tax Rate to Actual Income Tax Rate The tax provisions in the accompanying Consolidated Statements of Total Comprehensive Loss reflect effective tax rates differing from prevailing Federal corporate income tax rates. The following is a reconciliation of these differences: Year Ended December 31, 2022 2021 2020 Tax on income (loss) at statutory rate $ 110 21 % $ — 21 % $ (92) 21 % Changes in expected tax resulting from: Tax-exempt interest (1) — % (2) (114) % (2) — % Foreign taxes 4 1 % 8 448 % 6 (1) % State Income Taxes (1) — % 14 794 % — — % Substantiation adjustment — — % — — % (29) 7 % Variable Interest Entities 25 5 % — — % — — % Valuation allowance (131) (25) % (4) (230) % 113 (26) % Other, net (4) (1) % 1 72 % 2 — % Tax expense on income (loss) $ 2 1 % $ 18 991 % $ (3) 1 %
Schedule of Net Operating Loss And Tax Credit Carryovers	Pursuant to a 2013 Closing Agreement between Ambac and the United States Internal Revenue Service ("IRS"), AAC could have to pay as much as $8 to the IRS in the year utilized should AAC utilize $2,142 of NOLs and Interest Expense Limitation available to it as of December 31, 2022.As of December 31, 2022, the Company has (i) $3,454 of NOLs, which if not utilized will begin expiring in 2030, and will fully expire in 2043, and (ii) $314 of interest expense tax deduction carryover, which has an indefinite carryforward period but is limited in any particular year based on certain provisions. Beginning in 2022, the Company is presenting these items separately in the deferred income tax table above with conforming display in 2021.

Employment Benefit Plans (Table

Employment Benefit Plans (Tables)	12 Months Ended
Employment Benefit Plans (Tables)	Dec. 31, 2022
Postemployment Benefits [Abstract]
Schedule of Expected Benefit Payments [Table Text Block]	The following table sets forth projected benefit payments from Ambac’s postretirement plan over the next ten years for current retirees: 2023 $ — 2024 — 2025 — 2026 — 2027 1 Thereafter 3 Total $ 5
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable [Table Text Block]	The amount of stock-based compensation expense and corresponding after-tax expense are as follows: Year Ended December 31, 2022 2021 2020 Restricted stock units 5 5 3 Performance awards 12 10 8 Total stock-based compensation $ 17 $ 14 $ 11 Total stock-based compensation (after-tax) $ 17 $ 14 $ 11
Share-based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block]	A summary of RSU activity for 2022 is as follows: Shares Weighted Average Grant Date Fair Value Per Share Outstanding at beginning of period 837,070 $ 17.82 Granted 352,141 $ 12.48 Delivered or returned to plan (1) (263,505) $ 17.13 Forfeited (2,456) $ 15.65 Outstanding at end of period 923,250 $ 15.94 (1) When restricted stock unit awards issued by Ambac become taxable compensation to employees, shares may be withheld to cover the employee’s withholding taxes. For the year ended December 31, 2022, Ambac withheld 97,871 shares from
Schedule of Nonvested Performance-based Units Activity [Table Text Block]	A summary of PSU activity for 2022 is as follows: Shares Weighted Average Outstanding at beginning of period 722,056 $ 18.97 Granted (1) 529,285 13.44 Delivered (2) (422,620) 19.42 Forfeited (7,361) 16.93 Performance adjustment (3) 97,591 19.17 Outstanding at end of period 918,951 $ 15.67 (1) Represents performance share units at 100% of units granted for LTIP Awards. (2) Reflects the number of performance shares attributable to the performance goals attained over the completed performance period and for which service conditions have been met. When performance stock unit awards issued by Ambac become taxable compensation to employees, shares may be withheld to cover the employee’s withholding taxes. For the year ended December 31, 2022, Ambac purchased 157,377 of shares from employees that settled performance based restricted stock units to meet the required tax withholdings. (3) Represents the number of additional shares issued for awards granted in 2019 as a result of actual performance during the performance period.

Leases (Tables)

Leases (Tables)	12 Months Ended
Leases (Tables)	Dec. 31, 2022
Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block]	Future undiscounted lease payments to be received are as follows: As of December 31, 2022 Operating Leases 2023 $ 1 2024 1 2025 1 2026 1 2027 1 Thereafter 3 Total lease receipts $ 9
Lease, Cost [Table Text Block]	The components of lease costs, net of sub-lessor income, is as follows: Year Ended December 31, 2022 2021 Operating lease cost $ 4 $ 5 Short-term lease cost — — Variable lease cost — — Sublease income (1) (1) Total lease cost $ 4 $ 4 Ambac is required to make variable lease payments under certain leases which primarily relates to variable costs of the lessor, such as taxes, insurance, maintenance and electricity. Supplemental information related to leases is as follows: Year Ended December 31, 2022 2021 Cash paid for amounts included in the measurement of operating lease liabilities $ 5 $ 5 Right-of-use assets obtained in exchange for operating lease liabilities (non-cash) — — Supplemental balance sheet information related to leases is as follows: December 31, 2022 2021 Operating leases: Operating lease right of use assets $ 21 $ 23 Operating lease liabilities 25 28 Weighted average remaining lease term: Operating leases 6.8 years 7.7 years Weighted average discount rate: Operating leases 7.8 % 7.7 %
Cash Flow, Supplemental Disclosures [Text Block]	Supplemental information related to leases is as follows: Year Ended December 31, 2022 2021 Cash paid for amounts included in the measurement of operating lease liabilities $ 5 $ 5 Right-of-use assets obtained in exchange for operating lease liabilities (non-cash) — —
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	Future undiscounted lease payments, gross of sublease receipts, to be made are as follows: As of December 31, 2022 Operating Leases 2023 $ 5 2024 5 2025 5 2026 4 2027 4 Thereafter 9 Total lease payments 32 Less: imputed interest (7) Total $ 25
Schedule of Supplemental Cash Flow Information [Table Text Block]	Supplemental Disclosure of Cash Flow Information Year Ended December 31, 2022 2021 2020 Cash paid during the period for: Income taxes $ 6 $ 15 $ 11 Interest on long-term debt 283 80 107 Non-cash investing and financing activities: Decrease in long-term debt as a result of surplus notes exchanges — 71 — Securities acquired in transactions related to Puerto Rico restructurings 508 — — Loans acquired through financial guarantee subrogation 20 — — VIE long-term debt issued related to Puerto Rico restructurings 583 — — December 31, 2022 2021 2020 Reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets to the Consolidated Statements of Cash Flow: Cash and cash equivalents $ 31 $ 17 $ 20 Restricted cash 14 5 13 Variable Interest Entity Restricted cash 17 2 2 Total cash, cash equivalents, and restricted cash shown on the Consolidated Statements of Cash Flows 61 23 35

Background and Business Descr_3

Background and Business Description Rehabilitation Exit Support Agreement (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Apr. 29, 1991	Dec. 31, 2016	Dec. 31, 2022	Dec. 31, 2021	May 01, 2013	Apr. 30, 2013
Preferred Stock, Shares Outstanding			0	0
Entity Incorporation, Date of Incorporation	Apr. 29, 1991
Common stock, shares authorized			130,000,000	130,000,000
Common Stock, Par or Stated Value Per Share						$ 0.01
Preferred stock, shares authorized			20,000,000	20,000,000
Preferred Stock, Par or Stated Value Per Share			$ 0.01			$ 0.01
Common stock, shares issued			46,658,990	46,477,068
Class of Warrant or Right, Exercise Price of Warrants or Rights					$ 16.67
Common Stock Voting Restrictions	10%
Common Stock Voting Restriction Less One Vote	10%
Common Stock Transfer Restrictions	5%
Common Stock Additional Transfer Restrictions		5%
Stockholders' Equity Attributable to Noncontrolling Interest			$ 53	$ 60
Ambac Assurance Corporation [Member]
Preferred Stock, Shares Outstanding			4,596	5,501
Preferred Stock, Liquidation Preference, Value			$ 115	$ 138

Background and Business Descr_4

Background and Business Description Tier 2 Commitment (Details) $ in Millions	Feb. 12, 2018 USD ($)
Tier 2 Note Security in RMBS Litigation Settlement Proceeds	$ 1,600

Background and Basis of Present

Background and Basis of Presentation - Surplus Note Exchange (Details)	3 Months Ended	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Feb. 11, 2021 USD ($)	Jan. 19, 2021 USD ($)
Insurance [Line Items]
Net realized gains on extinguishment of debt		$ 81,000,000	$ 33,000,000	$ 0
Realized Investment Gains (Losses)		31,000,000	7,000,000	22,000,000
Parent Company [Member]
Insurance [Line Items]
Realized Investment Gains (Losses)		(14,000,000)	(5,000,000)	$ (1,000,000)
Parent [Member]
Insurance [Line Items]
Realized Investment Gains (Losses)		4,000,000
5.1% Surplus Notes, General Account, Due 2020 [Member]
Insurance [Line Items]
Net realized gains on extinguishment of debt		(134,000,000)
Ambac Assurance Corporation [Member]
Insurance [Line Items]
Long-term Debt, Gross	$ 706,000,000	$ 706,000,000	$ 2,334,000,000
Ambac Assurance Corporation [Member] \| 5.1 % Surplus Notes Due 2020 [Member]
Insurance [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.10%	5.10%	5.10%
Ambac Assurance Corporation [Member] \| Corolla Notes
Insurance [Line Items]
Debt Instrument, Interest Rate, Stated Percentage						5.10%
5.1% Junior Surplus Notes, General Account Due 2020 [Member] \| Ambac Assurance Corporation [Member] \| Lease Reducing Notes
Insurance [Line Items]
Long-term Debt Reduced in Exchange					$ 15,000,000
5.1% Junior Surplus Notes, General Account Due 2020 [Member] \| Ambac Assurance Corporation [Member] \| Corolla Notes
Insurance [Line Items]
Payment Amount in Exchange						$ 0.9125
Note Holders	1
5.1% Junior Surplus Notes, General Account Due 2020 [Member] \| Ambac Assurance Corporation [Member] \| Corolla Certificate
Insurance [Line Items]
One Dollar Outstanding						1
Payment Amount in Exchange						0.64
5.1% Surplus Notes, General Account, Due 2020 [Member] \| Ambac Assurance Corporation [Member]
Insurance [Line Items]
Long-term Debt, Gross	$ 519,000,000	$ 519,000,000	$ 785,000,000
Net realized gains on extinguishment of debt		$ 33,000,000
5.1% Surplus Notes, General Account, Due 2020 [Member] \| Ambac Assurance Corporation [Member] \| Corolla Notes
Insurance [Line Items]
Long-term Debt Issued in Exchange Transaction						267,000,000
Corolla Notes \| Ambac Assurance Corporation [Member]
Insurance [Line Items]
One Dollar Outstanding						$ 1
Lease Reducing Notes \| Ambac Assurance Corporation [Member]
Insurance [Line Items]
One Dollar Outstanding					1
Payment Amount in Exchange					0.8581
Long-term Debt Issued in Exchange Transaction					$ 13,000,000
Lease Reducing Notes \| Ambac Assurance Corporation [Member] \| 5.1% Junior Surplus Notes Due 2020 [Member]
Insurance [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					5.10%

Background and Business Descr_5

Background and Business Description AMPS Exchange (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2022	Dec. 31, 2021	May 01, 2013
Stockholders' Equity Attributable to Noncontrolling Interest	$ 53	$ 60
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 16.67
Preferred Stock, Shares Outstanding	0	0
Ambac Assurance Corporation [Member]
Preferred Stock, Liquidation Preference, Value	$ 115	$ 138
Preferred Stock, Shares Outstanding	4,596	5,501

Background and Business Descr_6

Background and Business Description - Additional Information (Detail)		12 Months Ended
	Apr. 29, 1991	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($)	Dec. 31, 2016	Jul. 06, 2021 USD ($)	Feb. 12, 2018 USD ($)	May 01, 2013 $ / shares	Apr. 30, 2013 $ / shares
Background And Basis Of Presentation [Line Items]
Entity Incorporation, Date of Incorporation	Apr. 29, 1991
Tier 2 Note Security in RMBS Litigation Settlement Proceeds							$ 1,600,000,000
Common stock, shares authorized \| shares		130,000,000	130,000,000
Common Stock, Par or Stated Value Per Share \| $ / shares									$ 0.01
Preferred stock, shares authorized \| shares		20,000,000	20,000,000
Preferred Stock, Par or Stated Value Per Share \| $ / shares		$ 0.01							$ 0.01
Common stock, shares issued \| shares		46,658,990	46,477,068
Class of Warrant or Right, Exercise Price of Warrants or Rights \| $ / shares								$ 16.67
Common Stock Voting Restrictions	10%
Common Stock Voting Restriction Less One Vote	10%
Common Stock Transfer Restrictions	5%
Common Stock Additional Transfer Restrictions					5%
Financial Guarantee Insurance Contracts, Accelerated Premium Revenue, Amount		$ 8,000,000	$ 1,000,000	$ 12,000,000
Number of Admitted Carriers Owned		5
Number of Admitted Carrier Owned		5
Number of Reportable Segments		3
LIBOR + 4.5% Senor Secured Notes Due 2026 \| London Interbank Offered Rate (LIBOR) [Member]
Background And Basis Of Presentation [Line Items]
Debt Instrument, Interest Rate, Stated Percentage						4.50%
LSNI Secured Notes due 2023
Background And Basis Of Presentation [Line Items]
Repayment of Long-term Debt, Long-term Lease Obligation, and Capital Security		$ 1,163,000,000
Sitka Holdings, LLC \| LIBOR + 4.5% Senor Secured Notes Due 2026
Background And Basis Of Presentation [Line Items]
Debt Instrument, Face Amount						$ 1,175,000,000

Background and Business Descr_7

Background and Business Description - Redemption of Notes - USD ($) $ in Millions		12 Months Ended
	Jan. 15, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net realized gains on extinguishment of debt		$ 81	$ 33	$ 0
5.1% Surplus Notes, General Account, Due 2020 [Member]
Net realized gains on extinguishment of debt		(134)
Subsequent Event
Remaining Cash Required For Repayment of Tier 2 Notes	$ 6
Nomura Credit & Capital, Inc.
Proceeds from Legal Settlements		140
Nomura Credit & Capital, Inc. \| Subsequent Event
Proceeds from Legal Settlements	140
Sitka AAC Note \| Ambac Assurance Corporation [Member]
Repayments of Long-term Debt		$ 1,218
Long-term Debt, Repayment, Premium Paid on Principal		103%
Net realized gains on extinguishment of debt		$ 53
Portion of Gain (Loss) on Extinguishment of Debt Attributable to AACs Ownership of Sitka Notes		5
Tier 2 Notes [Member] \| Ambac Assurance Corporation [Member]
Repayments of Long-term Debt		$ 213
Tier 2 Notes [Member] \| Ambac Assurance Corporation [Member] \| Subsequent Event
Repayments of Long-term Debt	$ 146

Background and Business Descr_8

Background and Business Description - Settlement of RMBS Litigation - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2022	Sep. 30, 2021	Dec. 31, 2022	Dec. 31, 2021
Gain (Loss) Related to Litigation Settlement			$ 126	$ 0
Loss Reserves [Member]
Gain (Loss) Related to Litigation Settlement	$ 43	$ 319	362
Litigation Recoveries
Gain (Loss) Related to Litigation Settlement	126		126
Gain (loss) on extinguishment of debt
Gain (Loss) Related to Litigation Settlement	(53)		(53)
Gain (Loss) on Investments [Member]
Gain (Loss) Related to Litigation Settlement	5		5
R&W value
Loss and Loss Benjefit Relating to R&W Recoveries			123
Bank of America
Proceeds from Legal Settlements			1,840
Gain (Loss) Related to Litigation Settlement	$ 121	$ 319	440
Nomura Credit & Capital, Inc.
Proceeds from Legal Settlements			$ 140

Basis of Presentation and Sig_4

Basis of Presentation and Significant Accounting Policies Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended	12 Months Ended
	Apr. 29, 1991	Dec. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2016	Jun. 30, 2021	Dec. 31, 2019	Jul. 01, 2019	Apr. 30, 2013
Finite-Lived Intangible Assets [Line Items]
Operating Lease, Liability		$ 25	$ 25	$ 28
Income Taxes Paid			$ 6	$ 15	$ 11
Common Stock Voting Restrictions	10%
Common Stock, Par or Stated Value Per Share										$ 0.01
Entity Incorporation, Date of Incorporation	Apr. 29, 1991
Preferred stock, shares authorized		20,000,000	20,000,000	20,000,000
Preferred Stock, Par or Stated Value Per Share		$ 0.01	$ 0.01							$ 0.01
Common stock, shares issued		46,658,990	46,658,990	46,477,068
Warrant Exercised During Period Shares			0	132	34
Common Stock Transfer Restrictions	5%
Common Stock Additional Transfer Restrictions						5%
Restricted Cash		$ 14	$ 14	$ 5	$ 13
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		61	61	23	35			$ 81
UK Income Tax Rate							19%		25%
Restricted Cash		$ 14	$ 14	$ 5	13
Weighted average period of future premiums			8 years	8 years
Estimated Future Premium Payments Weighted Average Discounted Rate		3%	3%	2.20%
CECL Securities Factor for Consideration		20%	20%
Xchange
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life		14 years
Business Combination, Redeemable Noncontrolling Percentage		20%	20%
Business Combination, Redeemable Noncontrolling Percentage		20%	20%
Capacity Marine
Business Combination, Redeemable Noncontrolling Percentage		20%	20%
Business Combination, Redeemable Noncontrolling Percentage		20%	20%
All Trans
Business Combination, Redeemable Noncontrolling Percentage		15%	15%
Business Combination, Redeemable Noncontrolling Percentage		15%	15%
Minimum [Member] \| Furniture and Fixtures [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			3 years
Maximum [Member] \| Furniture and Fixtures [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			5 years
Fixed Income Securities [Member]
Investment income due and accrued		$ 10	$ 10	$ 10
Investment income due and accrued		10	10	10
Long-term Debt [Member]
Finite-Lived Intangible Assets [Line Items]
Interest Paid, Including Capitalized Interest, Operating and Investing Activities			283	80	107
Variable Interest Entity, Primary Beneficiary [Member]
Finite-Lived Intangible Assets [Line Items]
Restricted Cash		17	17	2	2
Restricted Cash		$ 17	$ 17	$ 2	$ 2
Estimated Future Premium Payments Weighted Average Discounted Rate		6.80%	6.80%	3%

Basis of Presentation and Sig_5

Basis of Presentation and Significant Accounting Policies FX gain (loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Foreign Currency Transaction Gain (Loss), before Tax	$ 11	$ (7)	$ (1)
Gain (Loss) on Investments [Member]
Foreign Currency Transaction Gain (Loss), before Tax	$ 14	$ (5)	$ (4)

Basis of Presentation and Sig_6

Basis of Presentation and Significant Accounting Policies Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Intangible assets	$ 326	$ 362
Goodwill, Impaired, Accumulated Impairment Loss	0
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	0
Impairment of Intangible Assets, Finite-lived	$ 0

Basis of Presentation and Sig_7

Basis of Presentation and Significant Accounting Policies Noncontrolling Interest (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($)
Stockholders' Equity Attributable to Noncontrolling Interest	$ 53	$ 60
Preferred Stock, Shares Outstanding \| shares	0	0
Redeemable Noncontrolling Interest, Equity, Carrying Amount	$ 20	$ 18	$ 7
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value	5	0
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest	(1)	(1)
Temporary Equity, Accretion to Redemption Value, Adjustment	$ (3)	$ 12
AMPS Shares Purchased	(905)
AMPS Gain Based on Carry Value	$ 1
AMPS Purchase Cash Paid	$ 8
Ambac Assurance Corporation [Member]
Preferred Stock, Shares Outstanding \| shares	4,596	5,501
Preferred Stock, Liquidation Preference, Value	$ 115	$ 138
Xchange
Business Acquisition, Percentage of Voting Interests Acquired	80%
Capacity Marine
Business Acquisition, Percentage of Voting Interests Acquired	80%
All Trans
Business Acquisition, Percentage of Voting Interests Acquired	85%
London Interbank Offered Rate (LIBOR) [Member]
Dividend Rate on Auction Rate Preferred Shares	200

Basis of Presentation and Sig_8

Basis of Presentation and Significant Accounting Policies Adoption of New Accounting Standards (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Operating Lease, Liability	$ 25	$ 28

Basis of Presentation and Sig_9

Basis of Presentation and Significant Accounting Policies Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Taxes Paid	$ 6	$ 15	$ 11
Restricted Cash	14	5	13
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	61	23	35	$ 81
Decrease in long-term debt as a result of surplus notes exchanges		71
Securities acquired in transactions related to Puerto Rico restructurings	508
Loans acquired through financial guarantee subrogation	20
VIE long-term debt issued related to Puerto Rico restructurings	583
Long-term Debt [Member]
Interest Paid, Including Capitalized Interest, Operating and Investing Activities	283	80	107
Variable Interest Entity, Primary Beneficiary [Member]
Restricted Cash	$ 17	$ 2	$ 2

Basis of Presentation and Si_10

Basis of Presentation and Significant Accounting Policies Restricted Cash - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Restricted Cash	$ 14	$ 5	$ 13
Insurance Distribution
Restricted Cash	$ 14	$ 5

Segment Reporting (Details)

Segment Reporting (Details) - USD ($) $ in Millions	12 Months Ended
Segment Reporting (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Premiums Earned, Net	$ 56	$ 47	$ 54
Insurance Commissions and Fees	31	26
Contractually Specified Servicing Fee, Late Fee, and Ancillary Fee Earned in Exchange for Servicing Financial Asset	3	0	0
Net Investment Income	17	139	122
Realized Investment Gains (Losses)	31	7	22
Derivative, Gain (Loss) on Derivative, Net	129	22	(50)
Net realized gains on extinguishment of debt	81	33	0
Other income Items	31	8
Losses and loss adjustment expenses (benefit)		(88)	225
Deferred Policy Acquisition Costs, Amortization Expense	3	1	0
Insurance Commissions	18	15
Operating Expenses	139	110
Depreciation	2	2	1
Amortization of intangible assets	47	55	57
Interest Expense	168	187
Benefits, Losses and Expenses	(20)	281	596
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	525	2
Assets	7,973	12,303
Gain (Loss) Related to Litigation Settlement	126	0
Revenues	505	282	$ 156
Policyholder Benefits and Claims Incurred, Net	(396)
Legacy Financial Guarantee
Premiums Earned, Net	42	46
Net Investment Income	12	138
Realized Investment Gains (Losses)	32	3
Derivative, Gain (Loss) on Derivative, Net	128	22
Net realized gains on extinguishment of debt	81	33
Other income Items	30	8
Losses and loss adjustment expenses (benefit)		(89)
Deferred Policy Acquisition Costs, Amortization Expense	0	0
Operating Expenses	102	77
Depreciation	2	2
Amortization of intangible assets	44	52
Interest Expense	168	187
Benefits, Losses and Expenses	(89)	230
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	540	20
Assets	7,292	11,871
Gain (Loss) Related to Litigation Settlement	126	0
Revenues	451	250
Policyholder Benefits and Claims Incurred, Net	(406)
Corporate and Other
Net Investment Income	3	1
Realized Investment Gains (Losses)	0
Derivative, Gain (Loss) on Derivative, Net	1
Other income Items	0	0
Operating Expenses	17	19
Depreciation	0	0
Benefits, Losses and Expenses	17	19
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(14)	(15)
Assets	226	182
Revenues	4	5
Property and Casualty, Commercial Insurance
Premiums Earned, Net	14	1
Contractually Specified Servicing Fee, Late Fee, and Ancillary Fee Earned in Exchange for Servicing Financial Asset	3	0
Net Investment Income	2	1
Other income Items	0	0
Losses and loss adjustment expenses (benefit)		0
Deferred Policy Acquisition Costs, Amortization Expense	3	0
Operating Expenses	13	9
Depreciation	0	0
Benefits, Losses and Expenses	25	9
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(6)	(8)
Assets	316	156
Revenues	18	2
Policyholder Benefits and Claims Incurred, Net	9	0
Insurance Distribution
Insurance Commissions and Fees	31	26
Other income Items	1	0
Insurance Commissions	18	15
Operating Expenses	6	5
Depreciation	0	0
Amortization of intangible assets	3	3
Benefits, Losses and Expenses	27	22
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	5	4
Assets	138	93
Revenues	$ 31	$ 26

Business Combinations (Details)

Business Combinations (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Business Combinations (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2022	Dec. 31, 2020	Nov. 01, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Goodwill, Acquired During Period		$ 15
Redeemable Noncontrolling Interest, Equity, Carrying Amount	$ 20	20	$ 7		$ 18
2018	31	31
2019	29	29
2020	27	27
2021	25	25
2022	23	23
Thereafter	$ 178	$ 178
Business Combination, Goodwill Expected Tax Deductible Amount, Amortization Period		15 years	15 years
AllTrans & Capacity Marine
Business Acquisition [Line Items]
Business Combination, Consideration Transferred		$ 26
Xchange
Business Acquisition [Line Items]
Business Combination, Consideration Transferred			$ 81
AllTrans & Capacity Marine
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years
Distribution Relationships
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years
Non-compete Agreements
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years
Trade Names
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	8 years
Distribution Relationships
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross			33
Non-compete Agreements
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross			1
Trade Names
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross			1
Xchange
Business Acquisition [Line Items]
Business Combination, Consideration Transferred	$ 81
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents			2
BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedrResstrictedCash			4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill			36
Goodwill, Acquired During Period	46
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets			8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets			96
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable			8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities			8
Redeemable Noncontrolling Interest, Equity, Carrying Amount					7
Business Acquisition, Goodwill, Expected Tax Deductible Amount	21	21	65
AllTrans & Capacity Marine
Business Acquisition [Line Items]
Business Combination, Consideration Transferred	26
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents				$ 4
BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedrResstrictedCash				4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	16	$ 16		16
Goodwill, Acquired During Period	$ 15
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets				6
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets				45
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable				13
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities				$ 13
Redeemable Noncontrolling Interest, Equity, Carrying Amount					$ 5
AllTrans & Capacity Marine \| Distribution Relationships
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years
AllTrans & Capacity Marine \| Trade Names
Business Acquisition [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years
AllTrans & Capacity Marine \| Distribution Relationships
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross			15
AllTrans & Capacity Marine \| Trade Names
Business Acquisition [Line Items]
Finite-Lived Intangible Assets, Gross			$ 1

Investments - Summary of Amorti

Investments - Summary of Amortized Cost and Estimated Fair Value of Available-for-Sale Investments, Excluding VIE Investments (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 2,041
Gross Unrealized Gains	31	$ 141
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	106	16
Available-for-sale Securities, Current	1,966	2,265
Available-for-sale Securities	1,966
Available-for-sale Securities, Amortized Cost Basis	2,041	2,140
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	106	16
Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gains	0	0
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	0	0
Available-for-sale Securities	507	414
Available-for-sale Securities, Amortized Cost Basis	507	415
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Fixed Income Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,469	1,605
Gross Unrealized Gains	31	141
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	106	16
Available-for-sale Securities	1,395	1,730
Available-for-sale Securities, Amortized Cost Basis	1,469	1,605
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	106	16
Fixed Income Securities [Member] \| Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gains	0	28
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	2	3
Available-for-sale Securities	43	340
Available-for-sale Securities, Amortized Cost Basis	44	315
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	2	3
Fixed Income Securities [Member] \| Corporate Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gains	1	10
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	63	9
Available-for-sale Securities	598	613
Available-for-sale Securities, Amortized Cost Basis	659	612
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	63	9
Fixed Income Securities [Member] \| Debt Security, Government, Non-US [Member]
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gains	0	0
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	9	2
Available-for-sale Securities	76	87
Available-for-sale Securities, Amortized Cost Basis	85	89
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	9	2
Fixed Income Securities [Member] \| U.S. Government Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gains	0	1
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	4	1
Available-for-sale Securities	65	45
Available-for-sale Securities, Amortized Cost Basis	68	45
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	4	1
Fixed Income Securities [Member] \| Residential Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	230
Gross Unrealized Gains	28	70
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	19	0
Available-for-sale Securities	238	252
Available-for-sale Securities, Amortized Cost Basis	230	182
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	19	0
Fixed Income Securities [Member] \| Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	141
Gross Unrealized Gains	0	0
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	4	0
Available-for-sale Securities	137	128
Available-for-sale Securities, Amortized Cost Basis	141	128
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	4	0
Fixed Income Securities [Member] \| Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	227
Gross Unrealized Gains	2	32
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	5	0
Available-for-sale Securities	224	265
Available-for-sale Securities, Amortized Cost Basis	227	234
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	$ 5	0
Dbt Securities Available for Sale Unrealized Loss Measured as a Percent of Amortized Cost	2%
Fixed Income Securities [Member] \| Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 15
Gross Unrealized Gains	0
Available-for-sale Securities	15
Available-for-sale Securities, Amortized Cost Basis	15
Debt Securities, Available-for-sale, Allowance for Credit Loss	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0
Fixed Income Securities [Member] \| Collateralized Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	0
Available-for-sale Securities, Amortized Cost Basis	15
Fixed Income Investments And Other Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gains	31	141
Available-for-sale Securities	1,902	2,145
Available-for-sale Securities, Amortized Cost Basis	1,977	2,020
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	106	16
Collateral Pledged [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities	64	120
Collateral Pledged [Member] \| Fixed Income Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	0	15
Gross Unrealized Gains	0	0
Available-for-sale Securities	0	15
Available-for-sale Securities, 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]
Gross Unrealized Gains	0	0
Available-for-sale Securities	64	105
Available-for-sale Securities, Amortized Cost Basis	64	105
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Collateral Pledged [Member] \| Fixed Income Securities [Member] \| US Treasury and Government
Debt Securities, Available-for-sale [Line Items]
Gross Unrealized Gains		0
Available-for-sale Securities		15
Available-for-sale Securities, Amortized Cost Basis		15
Debt Securities, Available-for-sale, Allowance for Credit Loss		0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax		0
Asset Pledged as Collateral [Member] \| Fixed Income Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Amortized Cost Basis	64	120
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 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 (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Amortized Cost, Due in one year or less	$ 606
Amortized Cost, Due after one year through five years	456
Amortized Cost, Due after five years through ten years	317
Amortized Cost, Due after ten years	51
Amortized Cost, Total	1,429
Fixed income securities, amortized cost	2,041
Estimated Fair Value, Due in one year or less	605
Estimated Fair Value, Due after one year through five years	427
Estimated Fair Value, Due after five years through ten years	277
Estimated Fair Value, Due after ten years	43
Estimated Fair Value due, Total	1,353
Debt Securities, Available-for-sale	1,966
Fixed Income Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed income securities, amortized cost	1,469	$ 1,605
Debt Securities, Available-for-sale	1,395	1,730
Fixed Income Securities [Member] \| Residential Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed income securities, amortized cost	230
Debt Securities, Available-for-sale	238	252
Fixed Income Securities [Member] \| Collateralized Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed income securities, amortized cost	141
Debt Securities, Available-for-sale	137	128
Fixed Income Securities [Member] \| Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed income securities, amortized cost	227
Debt Securities, Available-for-sale	$ 224	$ 265

Investments - Summary of Gross

Investments - Summary of Gross Unrealized Losses and Fair Values of Ambac's Available-for-Sale Investments (Detail) $ in Millions	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months		$ 768
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 53	14
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	400	41
Available For Sale Securities Continuous Unrealized Loss Position 12 Months Or Longer Aggregate Losses Accumulated In Investments	53	1
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		810
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	106	16
Debt Securities Accumulated Gross Unrealized Loss Before Tax Included Pledged Securities		16
Debt Securities, Available for sale, Unrealized Loss Position, Including Pledged Securities	1,269	825
Debt Securities , Available for sale, Continuous Unrealized Loss Position,	869
Available-for-sale Securities	$ 1,966
Average Percentage Loss Versus Amortized Cost	10%
Average Percentage of Unrealized Loss Versus Amortized Cost for Below Investment Grade Securities	8%
Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 78	114
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	8	13
Available For Sale Securities Continuous Unrealized Loss Position 12 Months Or Longer Aggregate Losses Accumulated In Investments	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	86	128
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	0	0
Available-for-sale Securities	$ 507	414
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
Fixed Income Investments And Other Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities	$ 1,902	2,145
Fixed Income Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	791	654
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	53	14
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	392	28
Available For Sale Securities Continuous Unrealized Loss Position 12 Months Or Longer Aggregate Losses Accumulated In Investments	53	1
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,183	682
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	106	16
Available-for-sale Securities	1,395	1,730
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	21	117
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1	3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	7	2
Available For Sale Securities Continuous Unrealized Loss Position 12 Months Or Longer Aggregate Losses Accumulated In Investments	1	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	28	118
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	2	3
Available-for-sale Securities	43	340
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	40	25
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	3	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	19	2
Available For Sale Securities Continuous Unrealized Loss Position 12 Months Or Longer Aggregate Losses Accumulated In Investments	1	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	58	27
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	4	1
Available-for-sale Securities	65	45
Fixed Income Securities [Member] \| US Government Debt Securities [Member] \| Asset Pledged as Collateral [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months		15
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer		0
Available For Sale Securities Continuous Unrealized Loss Position 12 Months Or Longer Aggregate Losses Accumulated In Investments		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		15
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments		0
Debt Securities Available For Sale Continuous Unrealized Loss Position Less Than 12 Months Including Pledged Securities		783
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	280	363
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	21	8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	279	17
Available For Sale Securities Continuous Unrealized Loss Position 12 Months Or Longer Aggregate Losses Accumulated In Investments	42	1
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	559	380
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	$ 63	9
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	584
Available-for-sale Securities	$ 598	613
Fixed Income Securities [Member] \| Corporate Debt Securities [Member] \| External Credit Rating, Investment Grade
Debt Securities, Available-for-sale [Line Items]
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	61
Fixed Income Securities [Member] \| Corporate Debt Securities [Member] \| External Credit Rating, Non Investment Grade [Member]
Debt Securities, Available-for-sale [Line Items]
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	2
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	27	75
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	3
Available For Sale Securities Continuous Unrealized Loss Position 12 Months Or Longer Aggregate Losses Accumulated In Investments	7	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	73	78
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	9	2
Available-for-sale Securities	76	87
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	132	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	19	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	1
Available For Sale Securities Continuous Unrealized Loss Position 12 Months Or Longer Aggregate Losses Accumulated In Investments	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	132	2
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	19	0
Available-for-sale Securities	238	252
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	90	68
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	3	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	36	3
Available For Sale Securities Continuous Unrealized Loss Position 12 Months Or Longer Aggregate Losses Accumulated In Investments	1	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	126	71
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	4	0
Available-for-sale Securities	137	128
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	198	6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	5	0
Available For Sale Securities Continuous Unrealized Loss Position 12 Months Or Longer Aggregate Losses Accumulated In Investments	1	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	203	6
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	$ 5	0
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	14
Available-for-sale Securities	$ 224	265
Dbt Securities Available for Sale Unrealized Loss Measured as a Percent of Amortized Cost	2%
Fixed Income Securities [Member] \| Ambac Insured Securities
Debt Securities, Available-for-sale [Line Items]
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	$ 18
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	13
Dbt Securities Available for Sale Unrealized Loss Measured as a Percent of Amortized Cost	15%
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	$ 3
Available-for-sale Securities	15
Fixed Income Securities [Member] \| Collateralized Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0
Available For Sale Securities Continuous Unrealized Loss Position 12 Months Or Longer Aggregate Losses Accumulated In Investments	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	3
Available For Sale Securities Gross Unrealized Loss Accumulated In Investments	0
Collateral Pledged [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities	64	120
Collateral Pledged [Member] \| Fixed Income Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities	0	15
Collateral Pledged [Member] \| Fixed Income Securities [Member] \| Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities	$ 64	$ 105

Investments - Additional Inform

Investments - Additional Information (Detail)	3 Months Ended
Investments - Additional Information (Detail)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Reported Value Measurement [Member]
Investment [Line Items]
Other Investments	$ 61,000,000	$ 106,000,000
Reported Value Measurement [Member] \| Equity [Member]
Investment [Line Items]
Other Investments	53,000,000	82,000,000
Reported Value Measurement [Member] \| Emerging Market Debt [Member]
Investment [Line Items]
Other Investments	0	24,000,000
Other Investments	568,000,000	690,000,000
Securities fair value	23,000,000	17,000,000
Fair Value of Securities Deposited in Connection wtih Letter of Credit	1,000,000
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Equity Securities Excluded From Fair Value	12,000,000	8,000,000
Real Estate [Member]
Investment [Line Items]
Other Investments	22,000,000	33,000,000
Hedge Funds, Multi-strategy [Member]
Investment [Line Items]
Other Investments	186,000,000	216,000,000
Interest Rate Contract [Member]
Investment [Line Items]
Other Investments	80,000,000	78,000,000
Illiquid Investments [Member]
Investment [Line Items]
Other Investments	84,000,000	88,000,000
Insurance Linked [Member]
Investment [Line Items]
Other Investments	1,000,000	2,000,000
Equity [Member]
Investment [Line Items]
Other Investments	64,000,000	98,000,000
Credit Index Product [Member]
Investment [Line Items]
Other Investments	63,000,000	107,000,000
Equity investments in pooled funds [Member]
Investment [Line Items]
Other Investments	556,000,000	683,000,000
Private Equity Funds, US
Investment [Line Items]
Other Investments	47,000,000	37,000,000
Emerging Markets Debt
Investment [Line Items]
Other Investments	0	24,000,000
Convertibles and Bonds with Warrants Attached
Investment [Line Items]
Other Investments	8,000,000	0
Investment Portfolio [Member]
Investment [Line Items]
Fair Value of Cash and Securities Pledged to Derivative Counterparties	$ 64,000,000	$ 120,000,000
Ambac Assurance Corporation [Member] \| Corolla Notes \| 5.1% Junior Surplus Notes, General Account Due 2020 [Member]
Investment [Line Items]
Note Holders	1
Commitments [Member] \| Partnership Interest [Member]
Investment [Line Items]
Other Investments	$ 53,000,000

Investments - Summary of Amount

Investments - Summary of Amounts Included in Net Realized (Losses) Gains and Other-Than-Temporary Impairments (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Investment [Line Items]
Gross realized gains on securities	$ 36	$ 14	$ 38
Gross realized losses on securities	(18)	(2)	(12)
Foreign exchange (losses) gains	11	(7)	(1)
Debt Securities, Available-for-sale, Allowance for Credit Loss, Not to Sell before Recovery, Credit Loss, Previously Recorded, Expense (Reversal)	0	0	0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Sell before Recovery	0	0	0
Net realized (losses) gains	31	7	22
Gain (Loss) on Investments [Member]
Investment [Line Items]
Foreign exchange (losses) gains	$ 14	$ (5)	$ (4)

Investments - Summary of Roll-F

Investments - Summary of Roll-Forward of Ambac's Cumulative Credit Losses on Debt Securities for Which Portion of Other-than-Temporary Impairment was Recognized in Other Comprehensive Income (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Debt Securities, Available-for-sale, Allowance for Credit Loss	$ 0	$ 0

Investments - Summary of Source

Investments - Summary of Sources of Collateral Received and Various Investment Agreement in which Collateral Pledged (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Investment [Line Items]
Fair Value Of Securities Deposited With Governmental Authorities	$ 23	$ 17
Restricted Cash	$ 14	5	$ 13
Fair Value ol Securities Held by Ambac UK Where Capital Stock of AUK is Pledged as Collateral for Sitka AAC Note		$ 669

Investments - Summary of Fair V

Investments - Summary of Fair Value, Including Financial Guarantee, and Weighted-Average Underlying Rating, Excluding Financial Guarantee, of Insured Securities (Detail) - National Public Finance Guarantee Corporation [Member] - Standard & Poor's, BBB- Rating [Member] $ in Millions	Dec. 31, 2021 USD ($)
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	$ 2
Municipal Bonds [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	2
Corporate Debt Securities [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	$ 0

Investments - Summary of Fair_2

Investments - Summary of Fair Value, Including Financial Guarantee, and Weighted-Average Underlying Rating, Excluding Financial Guarantee, of Insured Securities (Detail2) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Investment [Line Items]
Securities fair value	$ 23	$ 17
Investment Portfolio [Member]
Investment [Line Items]
Fair Value of Cash and Securities Pledged to Derivative Counterparties	64	120
Standard & Poor's, B Rating
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	403
Standard & Poor's, B Rating \| Ambac Assurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	403
Standard & Poor's, B Rating \| Municipal Bonds [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	10
Standard & Poor's, B Rating \| Municipal Bonds [Member] \| Ambac Assurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	10
Standard & Poor's, B Rating \| Corporate Debt Securities [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	0
Standard & Poor's, B Rating \| Mortgage and Asset-Backed Securities [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	394
Standard & Poor's, B Rating \| Mortgage and Asset-Backed Securities [Member] \| Ambac Assurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors	$ 394
Standard & Poor's, BBB- Rating [Member] \| National Public Finance Guarantee Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		2
Standard & Poor's, BBB- Rating [Member] \| Municipal Bonds [Member] \| National Public Finance Guarantee Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		2
Standard & Poor's, BBB- Rating [Member] \| Corporate Debt Securities [Member] \| National Public Finance Guarantee Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		0
Standard & Poor's, C Rating \| Assured Guaranty Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		1
Standard & Poor's, C Rating \| Municipal Bonds [Member] \| Assured Guaranty Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		1
Standard & Poor's, C Rating \| Corporate Debt Securities [Member] \| Assured Guaranty Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		0
Standard & Poor's, CCC+ Rating
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		757
Standard & Poor's, CCC+ Rating \| Ambac Assurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		754
Standard & Poor's, CCC+ Rating \| Municipal Bonds [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		318
Standard & Poor's, CCC+ Rating \| Municipal Bonds [Member] \| Ambac Assurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		316
Standard & Poor's, CCC+ Rating \| Corporate Debt Securities [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		0
Standard & Poor's, CCC+ Rating \| Mortgage and Asset-Backed Securities [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		439
Standard & Poor's, CCC+ Rating \| Mortgage and Asset-Backed Securities [Member] \| Ambac Assurance Corporation [Member]
Investment [Line Items]
Fair value of securities that include benefit of guarantees provided by financial guarantors		$ 439

Investments - Summary of Net In

Investments - Summary of Net Investment Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Investment [Line Items]
Net Realized and Unrealized Gain (Loss) on Trading Securities	$ (48)	$ 23	$ 0
Trading Securities, Realized Gain (Loss)	(26)	1	(18)
Fixed income securities		78	103
Investment expense	(6)	(6)	(6)
Securities available-for-sale and short-term	66	74	103
Net investment income	17	139	122
Gains (losses) on securities held as of reporting date [Member]
Investment [Line Items]
Other Investments Income	(22)	22	18
Available-for-sale Securities [Member]
Investment [Line Items]
Fixed income securities	61
Short-term Investments [Member]
Investment [Line Items]
Fixed income securities	11	0	5
Financing Receivable [Member]
Investment [Line Items]
Fixed income securities	1	0	1
Other Investments [Member]
Investment [Line Items]
Fixed income securities	(26)	$ 66	$ 19
Debt Securities, Trading
Investment [Line Items]
Fixed income securities	$ (23)

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Carrying Amount and Fair Value of Ambac's Financial Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Carrying Amount [Member]
Financial assets:
Other Investments	$ 61,000	$ 106,000
Cash	44,000	21,000
Loans	10,000	3,000
Total financial assets	6,537,000	9,268,000
Financial liabilities:
Liabilities for net financial guarantees written	159,000	(866,000)
Long-term Debt	1,065,000	2,806,000
Total financial liabilities	5,418,000	8,190,000
Carrying Amount [Member] \| Variable Interest Entity [Member]
Financial assets:
Restricted cash	17,000	2,000
Loans, at fair value	1,829,000	2,718,000
Financial liabilities:
Long-term Debt	3,107,000	4,216,000
Carrying Amount [Member] \| Other Debt Obligations [Member]
Financial assets:
Other Investments	568,000	690,000
Carrying Amount [Member] \| Short-term Investments [Member]
Financial assets:
Short term investments	507,000	414,000
Carrying Amount [Member] \| Corporate Debt Securities [Member] \| Variable Interest Entity [Member]
Financial assets:
Debt Securities, Available-for-sale	1,828,000	3,320,000
Carrying Amount [Member] \| Municipal Bonds [Member] \| Variable Interest Entity [Member]
Financial assets:
Debt Securities, Available-for-sale	96,000	136,000
Debt Securities, Trading	43,000
Carrying Amount [Member] \| Interest Rate Swaps [Member]
Financial liabilities:
Derivative liabilities	38,000	94,000
Carrying Amount [Member] \| Interest Rate Swaps [Member] \| Variable Interest Entity [Member]
Financial assets:
Derivative assets	190,000
Financial liabilities:
Derivative liabilities	1,048,000	1,940,000
Carrying Amount [Member] \| Currency Swaps [Member] \| Variable Interest Entity [Member]
Financial assets:
Derivative assets	49,000	38,000
Carrying Amount [Member] \| Warrant [Member]
Financial assets:
Derivative assets	1,000
Total Fair Value [Member]
Financial assets:
Cash	44,000	21,000
Debt Securities, Available-for-sale	1,966,000
Other Investments	568,000	690,000
Derivative assets	28,000	76,000
Other assets	0
Financial liabilities:
Derivative liabilities	38,000	95,000
Credit valuation adjustment included in fair value of credit derivative liabilities	$ 32	$ 19
Estimated Future Premium Payments Weighted Average Discounted Rate	3%	2.20%
Variable Interest Entity [Member]
Financial assets:
Debt Securities, Available-for-sale	$ 1,967,000	$ 3,455,000
Loans, at fair value	1,829,000	2,718,000
Derivative assets	239,000	38,000
Financial liabilities:
Derivative liabilities	1,048,000	1,940,000
Long-term Debt	$ 2,788,000	$ 4,056,000
Estimated Future Premium Payments Weighted Average Discounted Rate	6.80%	3%
Short-term Investments [Member]
Financial assets:
Debt Securities, Available-for-sale	$ 507,000	$ 414,000
Corporate Debt Securities [Member] \| Variable Interest Entity [Member]
Financial assets:
Debt Securities, Available-for-sale	1,828,000	3,320,000
Municipal Bonds [Member] \| Variable Interest Entity [Member]
Financial assets:
Debt Securities, Available-for-sale	96,000	136,000
Debt Securities, Trading	43,000	0
Fair Value, Recurring [Member] \| Warrant [Member]
Financial assets:
Derivative assets	1,000
Other Assets [Member] \| Carrying Amount [Member] \| Interest Rate Swaps [Member]
Financial assets:
Derivative assets	27,000	76,000
Fair Value Measured at Net Asset Value Per Share [Member]
Financial assets:
Other Investments	494,000	577,000
Level 1 [Member]
Financial assets:
Cash	43,000	21,000
Total financial assets	833,000	750,000
Financial liabilities:
Liabilities for net financial guarantees written	0	0
Long-term Debt	0	0
Total financial liabilities	0	0
Level 1 [Member] \| Variable Interest Entity [Member]
Financial assets:
Restricted cash	17,000	2,000
Loans	0	0
Financial liabilities:
Long-term Debt	0	0
Level 1 [Member] \| Other Debt Obligations [Member]
Financial assets:
Other Investments	61,000	106,000
Level 1 [Member] \| Short-term Investments [Member]
Financial assets:
Short term investments	506,000	369,000
Level 1 [Member] \| Corporate Debt Securities [Member] \| Variable Interest Entity [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Level 1 [Member] \| Municipal Bonds [Member] \| Variable Interest Entity [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Debt Securities, Trading	0
Level 1 [Member] \| Interest Rate Swaps [Member]
Financial liabilities:
Derivative liabilities	0	0
Level 1 [Member] \| Interest Rate Swaps [Member] \| Variable Interest Entity [Member]
Financial assets:
Derivative assets	0
Financial liabilities:
Derivative liabilities	0	0
Level 1 [Member] \| Currency Swaps [Member] \| Variable Interest Entity [Member]
Financial assets:
Derivative assets	0	0
Level 1 [Member] \| Loans Receivable [Member]
Financial assets:
Loans	0	0
Level 1 [Member] \| Other Assets [Member] \| Interest Rate Swaps [Member]
Financial assets:
Derivative assets	0	0
Level 2 [Member]
Financial assets:
Cash	1,000	1,000
Total financial assets	1,425,000	1,732,000
Financial liabilities:
Liabilities for net financial guarantees written	0	0
Long-term Debt	864,000	2,575,000
Total financial liabilities	4,942,000	8,695,000
Level 2 [Member] \| Variable Interest Entity [Member]
Financial assets:
Restricted cash	0	0
Loans	0	0
Financial liabilities:
Long-term Debt	2,992,000	4,086,000
Level 2 [Member] \| Other Debt Obligations [Member]
Financial assets:
Other Investments	0	0
Level 2 [Member] \| Short-term Investments [Member]
Financial assets:
Short term investments	1,000	46,000
Level 2 [Member] \| Corporate Debt Securities [Member] \| Variable Interest Entity [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Level 2 [Member] \| Municipal Bonds [Member] \| Variable Interest Entity [Member]
Financial assets:
Debt Securities, Available-for-sale	96,000	136,000
Debt Securities, Trading	43,000
Level 2 [Member] \| Interest Rate Swaps [Member]
Financial liabilities:
Derivative liabilities	38,000	94,000
Level 2 [Member] \| Interest Rate Swaps [Member] \| Variable Interest Entity [Member]
Financial assets:
Derivative assets	190,000
Financial liabilities:
Derivative liabilities	1,048,000	1,940,000
Level 2 [Member] \| Currency Swaps [Member] \| Variable Interest Entity [Member]
Financial assets:
Derivative assets	49,000	38,000
Level 2 [Member] \| Loans Receivable [Member]
Financial assets:
Loans	0	0
Level 2 [Member] \| Other Assets [Member] \| Interest Rate Swaps [Member]
Financial assets:
Derivative assets	1,000	5,000
Level 3 [Member]
Financial assets:
Cash	0	0
Total financial assets	3,772,000	6,202,000
Financial liabilities:
Liabilities for net financial guarantees written	476,000	(112,000)
Long-term Debt	14,000	22,000
Total financial liabilities	644,000	79,000
Level 3 [Member] \| Variable Interest Entity [Member]
Financial assets:
Restricted cash	0	0
Loans	1,829,000	2,718,000
Financial liabilities:
Long-term Debt	154,000	169,000
Level 3 [Member] \| Other Debt Obligations [Member]
Financial assets:
Other Investments	0	0
Level 3 [Member] \| Short-term Investments [Member]
Financial assets:
Short term investments	0	0
Level 3 [Member] \| Corporate Debt Securities [Member] \| Variable Interest Entity [Member]
Financial assets:
Debt Securities, Available-for-sale	1,828,000	3,320,000
Level 3 [Member] \| Municipal Bonds [Member] \| Variable Interest Entity [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Debt Securities, Trading	0
Level 3 [Member] \| Interest Rate Swaps [Member]
Financial liabilities:
Derivative liabilities	0	0
Level 3 [Member] \| Interest Rate Swaps [Member] \| Variable Interest Entity [Member]
Financial liabilities:
Derivative liabilities	0	0
Level 3 [Member] \| Currency Swaps [Member] \| Variable Interest Entity [Member]
Financial assets:
Derivative assets	0	0
Level 3 [Member] \| Loans Receivable [Member]
Financial assets:
Loans	10,000	3,000
Level 3 [Member] \| Warrant [Member]
Financial assets:
Derivative assets	1,000
Level 3 [Member] \| Other Assets [Member] \| Interest Rate Swaps [Member]
Financial assets:
Derivative assets	26,000	71,000
Municipal Bonds [Member] \| Carrying Amount [Member]
Financial assets:
Debt Securities, Available-for-sale	102,000	340,000
Corporate Debt Securities [Member] \| Carrying Amount [Member]
Financial assets:
Debt Securities, Available-for-sale	598,000	613,000
Debt Security, Government, Non-US [Member] \| Carrying Amount [Member]
Financial assets:
Debt Securities, Available-for-sale	76,000	87,000
US Government Debt Securities [Member] \| Carrying Amount [Member]
Financial assets:
Debt Securities, Available-for-sale	65,000	45,000
Residential Mortgage-Backed Securities [Member] \| Carrying Amount [Member]
Financial assets:
Debt Securities, Available-for-sale	238,000	252,000
Collateralized Debt Obligations [Member] \| Carrying Amount [Member]
Financial assets:
Debt Securities, Available-for-sale	137,000	128,000
Asset-backed Securities [Member] \| Carrying Amount [Member]
Financial assets:
Debt Securities, Available-for-sale	224,000	265,000
Commercial Mortgage Backed Securities [Member] \| Carrying Amount [Member]
Financial assets:
Debt Securities, Available-for-sale	15,000
Fair Value, Recurring [Member]
Financial assets:
Total financial assets	6,525,000	9,261,000
Financial liabilities:
Liabilities for net financial guarantees written	476,000	(112,000)
Long-term Debt	878,000	2,598,000
Total financial liabilities	5,586,000	8,775,000
Fair Value, Recurring [Member] \| Variable Interest Entity [Member]
Financial assets:
Restricted cash	17,000	2,000
Loans	1,829,000	2,718,000
Financial liabilities:
Long-term Debt	3,145,000	4,255,000
Fair Value, Recurring [Member] \| Other Debt Obligations [Member]
Financial assets:
Other Investments	556,000	683,000
Fair Value, Recurring [Member] \| Short-term Investments [Member]
Financial assets:
Short term investments	507,000	414,000
Fair Value, Recurring [Member] \| Asset-backed Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	224,000	265,000
Fair Value, Recurring [Member] \| Collateralized Debt Obligations [Member]
Financial assets:
Debt Securities, Available-for-sale	137,000	128,000
Fair Value, Recurring [Member] \| Residential Mortgage-Backed Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	238,000	252,000
Fair Value, Recurring [Member] \| US Government Debt Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	65,000	45,000
Fair Value, Recurring [Member] \| Debt Security, Government, Non-US [Member]
Financial assets:
Debt Securities, Available-for-sale	76,000	87,000
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	598,000	613,000
Fair Value, Recurring [Member] \| Corporate Debt Securities [Member] \| Variable Interest Entity [Member]
Financial assets:
Debt Securities, Available-for-sale	1,828,000	3,320,000
Fair Value, Recurring [Member] \| Municipal Bonds [Member]
Financial assets:
Debt Securities, Available-for-sale	102,000	340,000
Fair Value, Recurring [Member] \| Municipal Bonds [Member] \| Variable Interest Entity [Member]
Financial assets:
Debt Securities, Available-for-sale	96,000	136,000
Debt Securities, Trading	43,000
Fair Value, Recurring [Member] \| Interest Rate Swaps [Member]
Financial liabilities:
Derivative liabilities	38,000	94,000
Fair Value, Recurring [Member] \| Interest Rate Swaps [Member] \| Variable Interest Entity [Member]
Financial assets:
Derivative assets	190,000
Financial liabilities:
Derivative liabilities	1,048,000	1,940,000
Fair Value, Recurring [Member] \| Currency Swaps [Member] \| Variable Interest Entity [Member]
Financial assets:
Derivative assets	49,000	38,000
Fair Value, Recurring [Member] \| Loans Receivable [Member]
Financial assets:
Loans	10,000	3,000
Fair Value, Recurring [Member] \| Commercial Mortgage Backed Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	15,000
Fair Value, Recurring [Member] \| Other Assets [Member] \| Interest Rate Swaps [Member]
Financial assets:
Derivative assets	27,000	76,000
Fair Value, Recurring [Member] \| Level 1 [Member] \| Asset-backed Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Fair Value, Recurring [Member] \| Level 1 [Member] \| Collateralized Debt Obligations [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Fair Value, Recurring [Member] \| Level 1 [Member] \| Residential Mortgage-Backed Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Fair Value, Recurring [Member] \| Level 1 [Member] \| US Government Debt Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	65,000	45,000
Fair Value, Recurring [Member] \| Level 1 [Member] \| Debt Security, Government, Non-US [Member]
Financial assets:
Debt Securities, Available-for-sale	76,000	87,000
Fair Value, Recurring [Member] \| Level 1 [Member] \| Corporate Debt Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	0	1,000
Fair Value, Recurring [Member] \| Level 1 [Member] \| Municipal Bonds [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Fair Value, Recurring [Member] \| Level 1 [Member] \| Commercial Mortgage Backed Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	0
Fair Value, Recurring [Member] \| Level 2 [Member] \| Asset-backed Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	157,000	187,000
Fair Value, Recurring [Member] \| Level 2 [Member] \| Collateralized Debt Obligations [Member]
Financial assets:
Debt Securities, Available-for-sale	137,000	128,000
Fair Value, Recurring [Member] \| Level 2 [Member] \| Residential Mortgage-Backed Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	238,000	252,000
Fair Value, Recurring [Member] \| Level 2 [Member] \| US Government Debt Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Fair Value, Recurring [Member] \| Level 2 [Member] \| Debt Security, Government, Non-US [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Fair Value, Recurring [Member] \| Level 2 [Member] \| Corporate Debt Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	585,000	600,000
Fair Value, Recurring [Member] \| Level 2 [Member] \| Municipal Bonds [Member]
Financial assets:
Debt Securities, Available-for-sale	102,000	340,000
Fair Value, Recurring [Member] \| Level 2 [Member] \| Commercial Mortgage Backed Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	15,000
Fair Value, Recurring [Member] \| Level 3 [Member] \| Asset-backed Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	67,000	79,000
Fair Value, Recurring [Member] \| Level 3 [Member] \| Collateralized Debt Obligations [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Fair Value, Recurring [Member] \| Level 3 [Member] \| Residential Mortgage-Backed Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Fair Value, Recurring [Member] \| Level 3 [Member] \| US Government Debt Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Fair Value, Recurring [Member] \| Level 3 [Member] \| Debt Security, Government, Non-US [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Fair Value, Recurring [Member] \| Level 3 [Member] \| Corporate Debt Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	12,000	12,000
Fair Value, Recurring [Member] \| Level 3 [Member] \| Municipal Bonds [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Fair Value, Recurring [Member] \| Level 3 [Member] \| Commercial Mortgage Backed Securities [Member]
Financial assets:
Debt Securities, Available-for-sale	0
Collateral Pledged [Member]
Financial assets:
Debt Securities, Available-for-sale	64,000	120,000
Collateral Pledged [Member] \| US Government Debt Securities [Member] \| Carrying Amount [Member]
Financial assets:
Debt Securities, Available-for-sale		15,000
Collateral Pledged [Member] \| Short-term Investments [Member] \| Carrying Amount [Member]
Financial assets:
Debt Securities, Available-for-sale	64,000	105,000
Collateral Pledged [Member] \| Fair Value, Recurring [Member] \| Short-term Investments [Member]
Financial assets:
Debt Securities, Available-for-sale	64,000	105,000
Collateral Pledged [Member] \| Fair Value, Recurring [Member] \| US Government Debt Securities [Member]
Financial assets:
Debt Securities, Available-for-sale		15,000
Collateral Pledged [Member] \| Fair Value, Recurring [Member] \| Level 1 [Member] \| Short-term Investments [Member]
Financial assets:
Debt Securities, Available-for-sale	64,000	105,000
Collateral Pledged [Member] \| Fair Value, Recurring [Member] \| Level 1 [Member] \| US Government Debt Securities [Member]
Financial assets:
Debt Securities, Available-for-sale		15,000
Collateral Pledged [Member] \| Fair Value, Recurring [Member] \| Level 2 [Member] \| Short-term Investments [Member]
Financial assets:
Debt Securities, Available-for-sale	0	0
Collateral Pledged [Member] \| Fair Value, Recurring [Member] \| Level 2 [Member] \| US Government Debt Securities [Member]
Financial assets:
Debt Securities, Available-for-sale		0
Collateral Pledged [Member] \| Fair Value, Recurring [Member] \| Level 3 [Member] \| Short-term Investments [Member]
Financial assets:
Debt Securities, Available-for-sale	$ 0	0
Collateral Pledged [Member] \| Fair Value, Recurring [Member] \| Level 3 [Member] \| US Government Debt Securities [Member]
Financial assets:
Debt Securities, Available-for-sale		$ 0

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Other Investments	$ 568,000	$ 690,000
Credit valuation adjustment included in fair value of credit derivative liabilities	32	19
Fair value of derivative liabilities	38,000
Derivative liabilities	$ 38,000	$ 95,000
Weighted average discounted rate of estimated future premium payments to be paid by the VIEs	3%	2.20%
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	5%	6%
Asset-backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Coupon rate	5.98%	5.97%
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	91%	90%
Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fair value of derivative liabilities	$ 0
Derivative liabilities	$ 1,048,000	$ 1,940,000
Weighted average discounted rate of estimated future premium payments to be paid by the VIEs	6.80%	3%
Real Estate [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Other Investments	$ 22,000	$ 33,000
Hedge Funds, Multi-strategy [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Other Investments	186,000	216,000
Interest Rate Contract [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Other Investments	80,000	78,000
Illiquid Investments [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Other Investments	$ 84,000	$ 88,000

Fair Value Measurements - Infor

Fair Value Measurements - Information about Valuation Inputs for Fixed Income Securities Classified as Level 3 (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Investments	$ 568	$ 690
Debt Securities, Available-for-sale	$ 1,966
Asset-backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Coupon rate	5.98%	5.97%
Fair Value Inputs Maturity	13 years 5 months 15 days	14 years 1 month 20 days
Yield	12.60%	10.20%
Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	$ 1,967	$ 3,455
Real Estate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Investments	22	33
Hedge Funds, Multi-strategy [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Investments	186	216
Interest Rate Contract [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Investments	80	78
Illiquid Investments [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Other Investments	84	88
Corporate Obligations [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	1,828	3,320
Corporate Obligations [Member] \| Variable Interest Entity, Primary Beneficiary [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	1,828	3,320
Fair Value, Recurring [Member] \| Residential Mortgage-Backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	238	252
Fair Value, Recurring [Member] \| Residential Mortgage-Backed Securities [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	0	0
Fair Value, Recurring [Member] \| Corporate Obligations [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	598	613
Fair Value, Recurring [Member] \| Corporate Obligations [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	$ 12	$ 12
Fair Value Inputs Maturity	1 year 9 months	2 years 9 months
Fair Value, Recurring [Member] \| Corporate Obligations [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Debt Securities, Available-for-sale	$ 1,828	$ 3,320

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 (Detail) $ in Millions	Dec. 31, 2022 USD ($)
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair value of derivative liabilities	$ 38

Fair Value Measurements - Sum_3

Fair Value Measurements - Summary of Information about Described Model Inputs Used to Determine Fair Value of Each Class of Credit Derivatives (Detail2) $ in Millions	Dec. 31, 2022 USD ($)
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair value of derivative liabilities	$ 38

Fair Value Measurements - Inf_2

Fair Value Measurements - Information about Valuation Inputs for Variable Interest Entity Assets and Liabilities Classified as Level 3 (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Estimated Future Premium Payments Weighted Average Discounted Rate	3%	2.20%
Asset-backed Securities [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Inputs Coupon Rate	5.98%	5.97%
Fair Value Inputs Maturity	13 years 5 months 15 days	14 years 1 month 20 days
Fair Value Inputs Yield	12.60%	10.20%
Variable Interest Entity [Member]
Fair Value Inputs, Liabilities, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held			$ 281
Estimated Future Premium Payments Weighted Average Discounted Rate	6.80%	3%
Estimated Future Premium Payments Minimum Discounted Rate	5.80%	2.20%
Estimated Future Premium Payments Maximum Discounted Rate	8.50%	4.10%

Fair Value Measurements - Sum_4

Fair Value Measurements - Summary of Changes in Level 3 Fair Value Category (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Financial Assets and Liabilities Transfers In or Out of Level 3	0
Fair Value Yield Rate	11.30%	11.60%
Asset-backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Number of Level 3 Security by Investment Type	1
Convertible Bonds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Number of Level 3 Security by Investment Type	2
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 Value	$ 3,762	$ 6,199	$ 6,376	$ 6,207
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	(1,160)		306
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)			198
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	(644)	(58)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		230
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	13	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(633)	(362)	(334)
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	1,160	(227)	(305)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	(644)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI		(59)	198
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 Value	79	91	78	72
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	1		1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)			6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	(12)	1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	13	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(1)	(2)	(1)
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)	1	(1)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	(12)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI		(1)	6
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 Value	0	0	1	3
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	0		(2)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)			0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0	(1)	0
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	0	0	2
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI		0	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 Value	26	70	84	66
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	(38)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)			0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings			25
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		(6)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(6)	(8)	(7)
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	38	6	(25)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	0
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI		0	0
Variable Interest Entity, Primary Beneficiary [Member] \| Level 3 [Member] \| Loans Receivable [Member] \| Loans [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 Value	1,829	2,718	2,998	3,108
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	(333)		98
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)			83
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	(279)	(26)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		59
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(278)	(313)	(290)
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	333	(59)	(98)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	(279)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI		(26)	83
Variable Interest Entity, Primary Beneficiary [Member] \| Level 3 [Member] \| Corporate Debt Securities [Member] \| Investments Contract [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 Value	1,828	3,320	3,215	$ 2,957
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	(789)		183
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)			109
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	(353)	(32)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		176
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(349)	(38)	(35)
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	789	(176)	(183)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI	$ (353)
Fair Value, Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss), OCI		$ (32)	$ 109

Fair Value Measurements - Sum_5

Fair Value Measurements - Summary of Gains and Losses (Realized and Unrealized) Relating to Level 3 Assets and Liabilities Included in Earnings (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Variable Interest Entity [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total gains or losses included in earnings for the period			$ 281
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held			281
Net Investment Income [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, Gain (Loss) Included in Earnings	$ 1	$ 1	1
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	1	1	0
Derivative Contract [Domain]
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, Gain (Loss) Included in Earnings	(38)	(6)	25
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	(39)	(6)	25
Income Loss On Variable Interest Entities [Member] \| Variable Interest Entity [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total gains or losses included in earnings for the period	(1,123)	235
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held	(1,123)	235
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	(2)
Fair Value Asset Or Liability Measured On Recurring Basis Change In Unrealized Gains Losses Still Held	$ 0	$ 0	$ (2)

Financial Guarantees in Force -

Financial Guarantees in Force - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Guarantor Obligations [Line Items]
Financial Guarantee Insurance Contracts, Accelerated Premium Revenue, Amount	$ 8	$ 1	$ 12
Gross par amount of financial guarantees outstanding	27,551	34,122
Net par amount of financial guarantees	22,613	28,020
Gross financial guarantees in force	44,734	54,272
Net financial guarantees in force	$ 34,975	42,653
Highest single insured risk of aggregate net par amount guaranteed	3.60%
Ceded Principal Outstanding Major Reinsurer Percentage	7.90%
Public Finance [Member]
Guarantor Obligations [Line Items]
Net par amount of financial guarantees	$ 10,547	12,360
Public Finance [Member] \| Housing Revenue [Member]
Guarantor Obligations [Line Items]
Net par amount of financial guarantees	5,491	5,610
Military Housing [Member] \| Public Finance [Member] \| Housing Revenue [Member]
Guarantor Obligations [Line Items]
Net par amount of financial guarantees	$ 5,400	$ 5,490

Financial Guarantees in Force_3

Financial Guarantees in Force - Summary of Financial Guarantee Portfolio Diversification by Type of Guaranteed Bond (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	$ 22,613	$ 28,020
Public Finance [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	10,547	12,360
Public Finance [Member] \| Lease and Tax-backed Revenue [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	1,979	3,196
Public Finance [Member] \| General Obligation [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	1,301	1,612
Public Finance [Member] \| Housing Revenue [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	5,491	5,610
Public Finance [Member] \| Other [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	1,776	1,942
Structured Finance [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	3,612	4,904
Structured Finance [Member] \| Mortgage-backed and Home Equity [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	1,930	2,724
Structured Finance [Member] \| Investor-owned Utilities [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	1,103	1,556
Structured Finance [Member] \| Other Structured Finance [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	579	624
International Finance [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	8,454	10,756
International Finance [Member] \| Asset Backed and Other [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	1,083	1,276
International Finance [Member] \| Investor-owned and Public Utilities [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	2,583	3,283
International Finance [Member] \| Sovereign/Sub-sovereign [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	4,077	5,141
International Finance [Member] \| Transportation [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	$ 711	$ 1,056

Financial Guarantees in Force_4

Financial Guarantees in Force - Summary of International Finance Guaranteed Portfolio (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	$ 22,613	$ 28,020
International Finance [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	8,454	10,756
International Finance [Member] \| United Kingdom [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	7,223	9,255
International Finance [Member] \| Australia [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	259	203
International Finance [Member] \| Italy [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	644	718
International Finance [Member] \| Austria [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	310	343
International Finance [Member] \| FRANCE
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	14	219
International Finance [Member] \| Other International [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	4	18
International Finance [Member] \| United States [Member]
Guarantor Obligations [Line Items]
Net Par Amount Outstanding	$ 14,159	$ 17,264

Financial Guarantee Insurance_3

Financial Guarantee Insurance Contracts - Additional Information (Detail) € in Millions, £ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2022 GBP (£)	Dec. 31, 2022 EUR (€)	Dec. 31, 2021 GBP (£)	Dec. 31, 2021 EUR (€)	Dec. 31, 2020 GBP (£)	Dec. 31, 2020 EUR (€)	Dec. 31, 2019 USD ($)
Insurance [Line Items]
Ceded Loss And Loss Expenses Paid Not Yet Recovered		$ 0	$ 0
Net par amount of financial guarantees	$ 22,613	$ 28,020
Estimated Future Premium Payments Weighted Average Discounted Rate	3%	2.20%		3%	3%	2.20%	2.20%
Financial Guarantee Insurance Contracts, Premium Receivable	$ 254	$ 320	370							$ 416
Amount Of Insured Par Outstanding Ceded To Reinsurer	$ 2,187
Ceded Principal Outstanding Major Reinsurer Percentage	7.90%
Reinsurance Payable	$ 39	$ 33
Weighted average period of future premiums	8 years	8 years
Uncollectable premium receivables	$ 5	$ 9
Accelerated premium revenue for retired obligations	8	1	12
Reinsurance recoveries of losses included in losses and loss expenses	(41)	5	(7)
Losses and loss expense reserves ceded to reinsurers		24
Subrogation recoveries, net of reinsurance	(140)	(1,704)
Amortization of intangible assets	47	55	57
Intangible assets	326	362
Financial Guarantee Outstanding Principal Ceded To Third Parties	4,938
Premiums Receivable, Gross	259	329
Allowance for Doubtful Accounts, Premiums and Other Receivables	5	9	17
Premium Receivable, Credit Loss Expense (Reversal)	(4)	(6)
Premium Receivable, Allowance for Credit Loss, Writeoff	0	(2)
Reinsurance Recoverable, Allowance for Credit Loss	0	0
Net Incurred RMBS Subrogation Recoveries	(123)	20	(23)
Reinsurance Recoverables, Gross	115
Net unsecured reinsurance recoverable	60
Reinsurance Recoverable, Gross, All Other	18
Unsecured Reinsurance Recoverable, All Other	7
Specialty Property & Casualty Program [Domain]
Insurance [Line Items]
Premiums Receivable, Gross	$ 16	2
Property and Casualty, Commercial Insurance
Insurance [Line Items]
Reinsurance, Reinsured Risk, Percentage	70%
Financial Guarantee
Insurance [Line Items]
Ceded Loss And Loss Expenses Paid Not Yet Recovered	$ 0
Losses and loss expense reserves ceded to reinsurers	33
Financial Guarantee \| Assured Guaranty Re Ltd [Member]
Insurance [Line Items]
Reinsurance Recoverables, Gross	30
Net unsecured reinsurance recoverable	0
Property and Casualty, Commercial Insurance \| QBE Insurance Corporation
Insurance [Line Items]
Reinsurance Recoverables, Gross	41
Net unsecured reinsurance recoverable	41
Property and Casualty, Commercial Insurance \| General Reinsurance Company
Insurance [Line Items]
Reinsurance Recoverables, Gross	25
Net unsecured reinsurance recoverable	11
Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross	217	277
IA [Member]
Insurance [Line Items]
Premiums Receivable, Gross	10	12
II [Member]
Insurance [Line Items]
Premiums Receivable, Gross	5	6
III [Member]
Insurance [Line Items]
Premiums Receivable, Gross	16	22
IV [Member]
Insurance [Line Items]
Premiums Receivable, Gross	$ 11	$ 12
Maximum [Member] \| Furniture and Fixtures [Member]
Insurance [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years
Loss Reserves [Member]
Insurance [Line Items]
Weighted average risk-free rate used to discount loss reserves	3.90%	1.20%
United Kingdom, Pounds
Insurance [Line Items]
Financial Guarantee Insurance Contracts, Premium Receivable	$ 71	$ 108	117	£ 59		£ 80		£ 86
Euro Member Countries, Euro
Insurance [Line Items]
Financial Guarantee Insurance Contracts, Premium Receivable	14	16	$ 19		€ 13		€ 14		€ 16
Public Finance [Member]
Insurance [Line Items]
Net par amount of financial guarantees	10,547	12,360
Premiums Receivable, Gross	150	159
Public Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross	142	151
Public Finance [Member] \| IA [Member]
Insurance [Line Items]
Premiums Receivable, Gross	3	3
Public Finance [Member] \| II [Member]
Insurance [Line Items]
Premiums Receivable, Gross	5	5
Public Finance [Member] \| III [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Public Finance [Member] \| IV [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Structured Finance [Member]
Insurance [Line Items]
Net par amount of financial guarantees	3,612	4,904
Premiums Receivable, Gross	24	45
Structured Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross	5	19
Structured Finance [Member] \| IA [Member]
Insurance [Line Items]
Premiums Receivable, Gross	1	1
Structured Finance [Member] \| II [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	1
Structured Finance [Member] \| III [Member]
Insurance [Line Items]
Premiums Receivable, Gross	7	12
Structured Finance [Member] \| IV [Member]
Insurance [Line Items]
Premiums Receivable, Gross	11	12
International Finance [Member]
Insurance [Line Items]
Net par amount of financial guarantees	8,454	10,756
Premiums Receivable, Gross	85	125
International Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross	70	107
International Finance [Member] \| IA [Member]
Insurance [Line Items]
Premiums Receivable, Gross	7	8
International Finance [Member] \| II [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
International Finance [Member] \| III [Member]
Insurance [Line Items]
Premiums Receivable, Gross	9	11
International Finance [Member] \| IV [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Housing Revenue [Member] \| Public Finance [Member]
Insurance [Line Items]
Net par amount of financial guarantees	5,491	5,610
Premiums Receivable, Gross	148	157
Housing Revenue [Member] \| Public Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross	140	149
Housing Revenue [Member] \| Public Finance [Member] \| IA [Member]
Insurance [Line Items]
Premiums Receivable, Gross	3	3
Housing Revenue [Member] \| Public Finance [Member] \| II [Member]
Insurance [Line Items]
Premiums Receivable, Gross	5	5
Housing Revenue [Member] \| Public Finance [Member] \| III [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Housing Revenue [Member] \| Public Finance [Member] \| IV [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Housing Revenue [Member] \| Military Housing [Member] \| Public Finance [Member]
Insurance [Line Items]
Net par amount of financial guarantees	5,400	5,490
Other Public Finance Sectors [Member] \| Public Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross	2	2
Other Public Finance Sectors [Member] \| Public Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross	2	2
Other Public Finance Sectors [Member] \| Public Finance [Member] \| IA [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Other Public Finance Sectors [Member] \| Public Finance [Member] \| II [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Other Public Finance Sectors [Member] \| Public Finance [Member] \| III [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Other Public Finance Sectors [Member] \| Public Finance [Member] \| IV [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Mortgage-backed and Home Equity [Member] \| Structured Finance [Member]
Insurance [Line Items]
Net par amount of financial guarantees	1,930	2,724
Premiums Receivable, Gross	11	16
Mortgage-backed and Home Equity [Member] \| Structured Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	1
Mortgage-backed and Home Equity [Member] \| Structured Finance [Member] \| IA [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Mortgage-backed and Home Equity [Member] \| Structured Finance [Member] \| II [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	1
Mortgage-backed and Home Equity [Member] \| Structured Finance [Member] \| III [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	2
Mortgage-backed and Home Equity [Member] \| Structured Finance [Member] \| IV [Member]
Insurance [Line Items]
Premiums Receivable, Gross	11	12
Structured Insurance [Member] \| Structured Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	10
Structured Insurance [Member] \| Structured Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	10
Structured Insurance [Member] \| Structured Finance [Member] \| IA [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Structured Insurance [Member] \| Structured Finance [Member] \| II [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Structured Insurance [Member] \| Structured Finance [Member] \| III [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Structured Insurance [Member] \| Structured Finance [Member] \| IV [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Student Loan [Member] \| Structured Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross	8	12
Student Loan [Member] \| Structured Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross	1	1
Student Loan [Member] \| Structured Finance [Member] \| IA [Member]
Insurance [Line Items]
Premiums Receivable, Gross	1	1
Student Loan [Member] \| Structured Finance [Member] \| II [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Student Loan [Member] \| Structured Finance [Member] \| III [Member]
Insurance [Line Items]
Premiums Receivable, Gross	7	9
Student Loan [Member] \| Structured Finance [Member] \| IV [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Other Structured Finance [Member] \| Structured Finance [Member]
Insurance [Line Items]
Net par amount of financial guarantees	579	624
Premiums Receivable, Gross	4	7
Other Structured Finance [Member] \| Structured Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross	4	7
Other Structured Finance [Member] \| Structured Finance [Member] \| IA [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Other Structured Finance [Member] \| Structured Finance [Member] \| II [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Other Structured Finance [Member] \| Structured Finance [Member] \| III [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Other Structured Finance [Member] \| Structured Finance [Member] \| IV [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Sovereign/Sub-sovereign [Member] \| International Finance [Member]
Insurance [Line Items]
Net par amount of financial guarantees	4,077	5,141
Premiums Receivable, Gross	64	93
Sovereign/Sub-sovereign [Member] \| International Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross	49	74
Sovereign/Sub-sovereign [Member] \| International Finance [Member] \| IA [Member]
Insurance [Line Items]
Premiums Receivable, Gross	7	8
Sovereign/Sub-sovereign [Member] \| International Finance [Member] \| II [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Sovereign/Sub-sovereign [Member] \| International Finance [Member] \| III [Member]
Insurance [Line Items]
Premiums Receivable, Gross	9	11
Sovereign/Sub-sovereign [Member] \| International Finance [Member] \| IV [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Investor-owned and Public Utilities [Member] \| International Finance [Member]
Insurance [Line Items]
Net par amount of financial guarantees	2,583	3,283
Premiums Receivable, Gross	18	28
Investor-owned and Public Utilities [Member] \| International Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross	18	28
Investor-owned and Public Utilities [Member] \| International Finance [Member] \| IA [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Investor-owned and Public Utilities [Member] \| International Finance [Member] \| II [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Investor-owned and Public Utilities [Member] \| International Finance [Member] \| III [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Investor-owned and Public Utilities [Member] \| International Finance [Member] \| IV [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Other International [Member] \| International Finance [Member]
Insurance [Line Items]
Premiums Receivable, Gross	2	5
Other International [Member] \| International Finance [Member] \| Surveillance Category One [Member]
Insurance [Line Items]
Premiums Receivable, Gross	2	5
Other International [Member] \| International Finance [Member] \| IA [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Other International [Member] \| International Finance [Member] \| II [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Other International [Member] \| International Finance [Member] \| III [Member]
Insurance [Line Items]
Premiums Receivable, Gross	0	0
Other International [Member] \| International Finance [Member] \| IV [Member]
Insurance [Line Items]
Premiums Receivable, Gross	$ 0	$ 0

Financial Guarantee Insurance_4

Financial Guarantee Insurance Contracts - Summary of Gross Premium Receivable Roll-Forward (Direct and Assumed Contracts) (Detail) € in Millions, £ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2022 GBP (£)	Dec. 31, 2022 EUR (€)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 GBP (£)	Dec. 31, 2021 EUR (€)	Dec. 31, 2020 USD ($)	Jan. 01, 2020 USD ($)	Dec. 31, 2019 USD ($)
Insurance [Line Items]
Premium Receivable, Allowance for Credit Loss	$ 5			$ 9
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Beginning premium receivable	320			370			$ 416
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,305			1,098			1,140		$ 1,536
Premium receipts	36			35			(46)
Adjustments for changes in expected and contractual cash flows	(31)			(27)			(6)
Accretion of premium receivable discount	8			8			9
Uncollectable premiums	4			8			(4)
Other adjustments (including foreign exchange)	(12)			(4)			5
Ending premium receivable	254			320			370
Allowance for Doubtful Accounts, Premiums and Other Receivables	5			9			17
Premium Receivable, Credit Loss Expense (Reversal)	(4)			(6)
Premium Receivable, Allowance for Credit Loss, Writeoff	0			(2)
Premiums Receivable, Gross	259			329
Premium Receivable, Allowance for Credit Loss, Recovery	0			0
Financial Guarantee Insurance Contracts, Premiums Receivable, Increase (Decrease), Foreign Exchange	(13)			(2)			4
Past Due Premiums	0			0
Specialty Property & Casualty Program [Domain]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	16			2
Surveillance Category One [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	217			277
IA [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	10			12
II [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	5			6
III [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	16			22
IV [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	11			12
Premiums Receivable [Member] \| Accounting Standards Update 2016-13 [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest								$ (3)
United Kingdom, Pounds
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Beginning premium receivable	108	£ 80		117	£ 86
Ending premium receivable	71	£ 59		108	£ 80		117
Euro Member Countries, Euro
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Beginning premium receivable	16		€ 14	19		€ 16
Ending premium receivable	14		€ 13	16		€ 14	$ 19
Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	24			45
Structured Finance [Member] \| Mortgage-backed and Home Equity [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	11			16
Structured Finance [Member] \| Student Loan [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	8			12
Structured Finance [Member] \| Structured Insurance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			10
Structured Finance [Member] \| Other Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	4			7
Structured Finance [Member] \| Surveillance Category One [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	5			19
Structured Finance [Member] \| Surveillance Category One [Member] \| Mortgage-backed and Home Equity [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			1
Structured Finance [Member] \| Surveillance Category One [Member] \| Student Loan [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	1			1
Structured Finance [Member] \| Surveillance Category One [Member] \| Structured Insurance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			10
Structured Finance [Member] \| Surveillance Category One [Member] \| Other Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	4			7
Structured Finance [Member] \| IA [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	1			1
Structured Finance [Member] \| IA [Member] \| Mortgage-backed and Home Equity [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Structured Finance [Member] \| IA [Member] \| Student Loan [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	1			1
Structured Finance [Member] \| IA [Member] \| Structured Insurance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Structured Finance [Member] \| IA [Member] \| Other Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Structured Finance [Member] \| II [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			1
Structured Finance [Member] \| II [Member] \| Mortgage-backed and Home Equity [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			1
Structured Finance [Member] \| II [Member] \| Student Loan [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Structured Finance [Member] \| II [Member] \| Structured Insurance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Structured Finance [Member] \| II [Member] \| Other Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Structured Finance [Member] \| III [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	7			12
Structured Finance [Member] \| III [Member] \| Mortgage-backed and Home Equity [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			2
Structured Finance [Member] \| III [Member] \| Student Loan [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	7			9
Structured Finance [Member] \| III [Member] \| Structured Insurance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Structured Finance [Member] \| III [Member] \| Other Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Structured Finance [Member] \| IV [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	11			12
Structured Finance [Member] \| IV [Member] \| Mortgage-backed and Home Equity [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	11			12
Structured Finance [Member] \| IV [Member] \| Student Loan [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Structured Finance [Member] \| IV [Member] \| Structured Insurance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Structured Finance [Member] \| IV [Member] \| Other Structured Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Public Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	150			159
Public Finance [Member] \| Housing Revenue [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	148			157
Public Finance [Member] \| Other Public Finance Sectors [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	2			2
Public Finance [Member] \| Surveillance Category One [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	142			151
Public Finance [Member] \| Surveillance Category One [Member] \| Housing Revenue [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	140			149
Public Finance [Member] \| Surveillance Category One [Member] \| Other Public Finance Sectors [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	2			2
Public Finance [Member] \| IA [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	3			3
Public Finance [Member] \| IA [Member] \| Housing Revenue [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	3			3
Public Finance [Member] \| IA [Member] \| Other Public Finance Sectors [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Public Finance [Member] \| II [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	5			5
Public Finance [Member] \| II [Member] \| Housing Revenue [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	5			5
Public Finance [Member] \| II [Member] \| Other Public Finance Sectors [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Public Finance [Member] \| III [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Public Finance [Member] \| III [Member] \| Housing Revenue [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Public Finance [Member] \| III [Member] \| Other Public Finance Sectors [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Public Finance [Member] \| IV [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Public Finance [Member] \| IV [Member] \| Housing Revenue [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
Public Finance [Member] \| IV [Member] \| Other Public Finance Sectors [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
International Finance [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	85			125
International Finance [Member] \| Sovereign/Sub-sovereign [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	64			93
International Finance [Member] \| Investor-owned and Public Utilities [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	18			28
International Finance [Member] \| Other International [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	2			5
International Finance [Member] \| Surveillance Category One [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	70			107
International Finance [Member] \| Surveillance Category One [Member] \| Sovereign/Sub-sovereign [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	49			74
International Finance [Member] \| Surveillance Category One [Member] \| Investor-owned and Public Utilities [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	18			28
International Finance [Member] \| Surveillance Category One [Member] \| Other International [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	2			5
International Finance [Member] \| IA [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	7			8
International Finance [Member] \| IA [Member] \| Sovereign/Sub-sovereign [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	7			8
International Finance [Member] \| IA [Member] \| Investor-owned and Public Utilities [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
International Finance [Member] \| IA [Member] \| Other International [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
International Finance [Member] \| II [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
International Finance [Member] \| II [Member] \| Sovereign/Sub-sovereign [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
International Finance [Member] \| II [Member] \| Investor-owned and Public Utilities [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
International Finance [Member] \| II [Member] \| Other International [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
International Finance [Member] \| III [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	9			11
International Finance [Member] \| III [Member] \| Sovereign/Sub-sovereign [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	9			11
International Finance [Member] \| III [Member] \| Investor-owned and Public Utilities [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
International Finance [Member] \| III [Member] \| Other International [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
International Finance [Member] \| IV [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
International Finance [Member] \| IV [Member] \| Sovereign/Sub-sovereign [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
International Finance [Member] \| IV [Member] \| Investor-owned and Public Utilities [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	0			0
International Finance [Member] \| IV [Member] \| Other International [Member]
Financial Guarantee Insurance Contracts, Premium Receivable [Roll Forward]
Premiums Receivable, Gross	$ 0			$ 0

Financial Guarantee Insurance_5

Financial Guarantee Insurance Contracts - Effect of Reinsurance on Premiums Written and Earned (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Direct Premiums Written	$ (127)	$ (2)	$ 1
Assumed Reinsurance Premiums Written	0	0	0
Ceded Reinsurance Premiums Written	(104)	(35)	1
Premiums written, net of reinsurance	(23)	33	0
Direct Premiums Earned	126	62	65
Premiums Earned, Net	56	47	54
Assumed Reinsurance Premiums Earned	0	0	1
Ceded Reinsurance Premiums Earned	69	15	12
Reinsurance on premiums earned, Net	56	47	$ 54
Reinsurance Recoverable, Allowance for Credit Loss	$ 0	$ 0

Financial Guarantee Insurance_6

Financial Guarantee Insurance Contracts - Summarized Future Gross Undiscounted Premiums Expected to be Collected, and Future Expected Premiums Earned, Net of Reinsurance (Detail) $ in Millions	Dec. 31, 2022 USD ($)
Future premiums expected to be collected, March 31, 2022	$ 8
Future premiums expected to be collected, June 30. 2022	7
Future premiums expected to be collected, September 30, 2022	7
Future premiums expected to be collected, December 31, 2022	5
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, 2026	23
Future premiums expected to be collected, December 31, 2031	95
Future premiums expected to be collected, December 31, 2036	59
Future premiums expected to be collected, December 31, 2041	27
Future premiums expected to be collected, December 31, 2046	13
Future premiums expected to be collected, December 31, 2051	4
Future premiums expected to be collected, December 31, 2056	0
Future premiums expected to be collected, Total	322
Future expected premium to be earned, net of reinsurance, March 31, 2022	5
Future expected premiums to be earned, net of reinsurance, June 30, 2022	5
Future expected premiums to be earned, net of reinsurance, September 30, 2022	5
Future expected premiums to be earned, net of reinsurance, December 31, 2022	5
Future expected premiums to be earned, net of reinsurance, December 31, 2023	19
Future expected premiums to be earned, net of reinsurance, December 31, 2024	18
Future expected premiums to be earned, net of reinsurance, December 31, 2025	18
Future expected premiums to be earned, net of reinsurance, December 31, 2026	17
Future expected premiums to be earned, net of reinsurance, December 31, 2031	70
Future expected premiums to be earned, net of reinsurance, December 31, 2036	42
Future expected premiums to be earned, net of reinsurance, December 31, 2041	17
Future expected premiums to be earned, net of reinsurance, December 31, 2046	8
Future expected premiums to be earned, net of reinsurance, December 31, 2051	2
Future expected premiums to be earned, net of reinsurance, December 31, 2056	0
Future expected premiums to be earned, net of reinsurance, Total	$ 231

Financial Guarantee Insurance_7

Financial Guarantee Insurance Contracts Financial Guarantee Insurance Contracts - Components of Loss and Loss Expense Reserves and Subrogation Recoverable (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Components of Loss and Loss Expense Reserves and Subrogation Recoverable [Line Items]
Policyholder Benefits and Claims Incurred, Ceded	$ 41	$ (5)	$ 7
Liability for Unpaid Claims and Claims Adjustment Expense, Net	883	(578)	(430)	$ (508)
Subrogation recoverable	(271)	(2,092)
Claim liability reported on Balance Sheet, before reinsurance		(554)
Liability for Claims and Claims Adjustment Expense	805	1,570
Liabillity for Claim and Claim Adjustment Expense, with Impact of VIE Consolidation	534	(522)	(397)	$ (482)
Premiums Earned, Net	56	47	$ 54
Legacy Financial Guarantee
Components of Loss and Loss Expense Reserves and Subrogation Recoverable [Line Items]
Premiums Earned, Net	42	46
Property and Casualty, Commercial Insurance
Components of Loss and Loss Expense Reserves and Subrogation Recoverable [Line Items]
Liability for Claims and Claims Adjustment Expense	90	32
Premiums Earned, Net	14	1
Property and Casualty, Commercial Insurance
Components of Loss and Loss Expense Reserves and Subrogation Recoverable [Line Items]
Liability for Claims and Claims Adjustment Expense	90	32
Liabillity for Claim and Claim Adjustment Expense, with Impact of VIE Consolidation	90	32
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	(28)	(56)
Liability for Claims and Claims Adjustment Expense	(28)	(56)
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	5	88
Claim liability reported on Balance Sheet, before reinsurance	791	1,837
Liability for Claims and Claims Adjustment Expense	787	1,749
Present Value of Expected Net Cash Flows-Recoveries [Member]
Components of Loss and Loss Expense Reserves and Subrogation Recoverable [Line Items]
Subrogation recoverable	(276)	(2,180)
Claim liability reported on Balance Sheet, before reinsurance	(319)	(2,335)
Liability for Claims and Claims Adjustment Expense	$ (44)	$ (155)

Financial Guarantee Insurance_8

Financial Guarantee Insurance Contracts - Summary of Loss Reserve Roll-Forward, Net of Subrogation Recoverable and Reinsurance (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Loss And Loss Adjustment Expense Reserves [Line Items]
Impact of VIE Consolidation on Gross Loss and Loss Reserves	$ 464
Liability for Unpaid Claims and Claims Adjustment Expense, Foreign Currency Translation Gain (Loss)	(2)	$ 0	$ 2
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims	(397)	(88)	225
Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Rmbs Subrogation	(140)	(1,730)
Policyholder Benefits and Claims Incurred, Ceded	41	(5)	7
Net Incurred RMBS Subrogation Recoveries	123	(20)	23
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Less reinsurance on loss and loss expense reserves	24
Beginning balance of net loss and loss expense reserves	(578)	(430)	(508)
Current year:
Claim and loss expense payments, net of subrogation and reinsurance	(7)	0	(1)
Prior years:
Claim and loss expense (payments) recoveries, net of subrogation and reinsurance	1,867	(59)	(148)
Liability for Unpaid Claims and Claims Adjustment Expense, Net	883	(578)	(430)	$ (508)
Add reinsurance on loss and loss expense reserves		24
Liabillity for Claim and Claim Adjustment Expense, with Impact of VIE Consolidation	534	(522)	(397)	(482)
Balance Of Rmbs Subrogation Recoveries Net Of Reinsurance	(140)	(1,704)
Current Year Claims and Claims Adjustment Expense	4	0	15
Prior Year Claims and Claims Adjustment Expense	(401)	(89)	210
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid	(1,860)	59	149
Ceded Loss And Loss Expenses Paid Not Yet Recovered		0	0
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	115	$ 55	33	$ 26
Liability For Unpaid Claims And Claims Adjustment Expense Net of VIE Consolidation			$ (430)
Settled Litigation
Prior years:
Claim and loss expense (payments) recoveries, net of subrogation and reinsurance	$ (1,687)

Financial Guarantee Insurance_9

Financial Guarantee Insurance Contracts - Summary of Information Related to Policies Currently Included in Ambac's Loss Reserves or Subrogation Recoverable (Detail)	12 Months Ended
	Dec. 31, 2022 USD ($) Policies	Dec. 31, 2021 USD ($) Policies	Jul. 08, 2022 USD ($)	Mar. 15, 2022 USD ($)	Dec. 31, 2020 USD ($)
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Number of policies \| Policies	162	205
Remaining weighted-average contract period (in years)	13 years	14 years
Gross insured contractual payments outstanding:
Principal	$ 4,047,000,000	$ 6,302,000,000
Interest	1,750,000,000	2,984,000,000
Total	5,797,000,000	9,286,000,000
Gross undiscounted claim liability	1,279,000,000	2,095,000,000
Discount, gross claim liability	496,000,000	303,000,000
Gross claim liability before all subrogation and before reinsurance	783,000,000	1,792,000,000
Less:
Gross RMBS subrogation	(140,000,000)	(1,737,000,000)
Discount, RMBS subrogation	0	7,000,000
Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Rmbs Subrogation	(140,000,000)	(1,730,000,000)
Less:
Gross other subrogation	(233,000,000)	(633,000,000)
Discount, other subrogation	54,000,000	28,000,000
Discounted other subrogation, before reinsurance	(179,000,000)	(605,000,000)
Gross claim liability, net of all subrogation and discounts, before reinsurance	464,000,000	(543,000,000)
Less: Unearned premium reserves	(28,000,000)	(56,000,000)
Plus: Loss adjustment expenses reserves	8,000,000	45,000,000
Claim liability reported on Balance Sheet, before reinsurance		(554,000,000)
Reinsurance recoverable reported on Balance Sheet	33,000,000	23,000,000
Ceded Loss And Loss Expenses Paid Not Yet Recovered		0			$ 0
Loss Reserves Ceded To Reinsurers		$ 24,000,000
Public Finance Puerto Rico Net Par Outstanding	244,000,000
Cash Shared by PRHTA Creditors Under the PRHTA/CCDA/PSA	389,000,000
Percent of Creditor Clawback of SUT, Subject to Lifetime Cap			69%
Lifetime Cap of Creditor Clawback of SUT			$ 3,698,000,000
New PRHTA Bonds to be Issued			1,245,000,000
AAC Insured GO / PBA Bonds Satisfied or Eliminated				$ 94
Percent of Par of AACs Outstanding AAC-Insured PRIFA Eliminated				39%
Percent of Par of AACs Outstanding AAC-Insured CCDA Eliminated				19%
Amount of AAC-Insured Par of PRIFA and CCDA Eliminated				$ 172,000,000
PRHTA 1968 Bonds
Less:
New PRHTA Bonds to be Issued			646,400,000
PRHTA 1998 Bonds
Less:
New PRHTA Bonds to be Issued			$ 598,600,000
Financial Guarantee
Less:
Claim liability reported on Balance Sheet, before reinsurance	444,000,000
Ceded Loss And Loss Expenses Paid Not Yet Recovered	0
Loss Reserves Ceded To Reinsurers	$ 33,000,000
Loss Reserves [Member]
Less:
Weighted average risk-free rate used to discount loss reserves	3.90%	1.20%
Surveillance Category One [Member]
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Number of policies \| Policies	37	34
Remaining weighted-average contract period (in years)	7 years	9 years
Gross insured contractual payments outstanding:
Principal	$ 709,000,000	$ 904,000,000
Interest	526,000,000	589,000,000
Total	1,235,000,000	1,493,000,000
Gross undiscounted claim liability	4,000,000	5,000,000
Discount, gross claim liability	1,000,000	0
Gross claim liability before all subrogation and before reinsurance	3,000,000	5,000,000
Less:
Gross RMBS subrogation	0	0
Discount, RMBS subrogation	0	0
Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Rmbs Subrogation	0	0
Less:
Gross other subrogation	(14,000,000)	0
Discount, other subrogation	2,000,000	0
Discounted other subrogation, before reinsurance	(12,000,000)	0
Gross claim liability, net of all subrogation and discounts, before reinsurance	(9,000,000)	5,000,000
Less: Unearned premium reserves	(2,000,000)	(3,000,000)
Plus: Loss adjustment expenses reserves	1,000,000	1,000,000
Claim liability reported on Balance Sheet, before reinsurance	(10,000,000)	3,000,000
Reinsurance recoverable reported on Balance Sheet	$ 1,000,000	$ 1,000,000
IA [Member]
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Number of policies \| Policies	6	15
Remaining weighted-average contract period (in years)	19 years	12 years
Gross insured contractual payments outstanding:
Principal	$ 200,000,000	$ 840,000,000
Interest	198,000,000	612,000,000
Total	399,000,000	1,452,000,000
Gross undiscounted claim liability	4,000,000	16,000,000
Discount, gross claim liability	1,000,000	1,000,000
Gross claim liability before all subrogation and before reinsurance	3,000,000	15,000,000
Less:
Gross RMBS subrogation	0	0
Discount, RMBS subrogation	0	0
Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Rmbs Subrogation	0	0
Less:
Gross other subrogation	(4,000,000)	(5,000,000)
Discount, other subrogation	0	0
Discounted other subrogation, before reinsurance	(3,000,000)	(5,000,000)
Gross claim liability, net of all subrogation and discounts, before reinsurance	0	10,000,000
Less: Unearned premium reserves	(2,000,000)	(10,000,000)
Plus: Loss adjustment expenses reserves	1,000,000	0
Claim liability reported on Balance Sheet, before reinsurance	(2,000,000)	1,000,000
Reinsurance recoverable reported on Balance Sheet	$ 0	$ 1,000,000
II [Member]
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Number of policies \| Policies	9	7
Remaining weighted-average contract period (in years)	14 years	14 years
Gross insured contractual payments outstanding:
Principal	$ 459,000,000	$ 459,000,000
Interest	286,000,000	308,000,000
Total	745,000,000	767,000,000
Gross undiscounted claim liability	43,000,000	45,000,000
Discount, gross claim liability	7,000,000	3,000,000
Gross claim liability before all subrogation and before reinsurance	36,000,000	42,000,000
Less:
Gross RMBS subrogation	0	0
Discount, RMBS subrogation	0	0
Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Rmbs Subrogation	0	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	36,000,000	42,000,000
Less: Unearned premium reserves	(5,000,000)	(5,000,000)
Plus: Loss adjustment expenses reserves	0	0
Claim liability reported on Balance Sheet, before reinsurance	32,000,000	38,000,000
Reinsurance recoverable reported on Balance Sheet	$ 8,000,000	$ 10,000,000
III [Member]
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Number of policies \| Policies	12	14
Remaining weighted-average contract period (in years)	14 years	15 years
Gross insured contractual payments outstanding:
Principal	$ 1,000,000,000	$ 1,300,000,000
Interest	156,000,000	169,000,000
Total	1,156,000,000	1,469,000,000
Gross undiscounted claim liability	446,000,000	544,000,000
Discount, gross claim liability	162,000,000	109,000,000
Gross claim liability before all subrogation and before reinsurance	284,000,000	435,000,000
Less:
Gross RMBS subrogation	0	0
Discount, RMBS subrogation	0	0
Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Rmbs Subrogation	0	0
Less:
Gross other subrogation	(31,000,000)	(33,000,000)
Discount, other subrogation	5,000,000	2,000,000
Discounted other subrogation, before reinsurance	(26,000,000)	(31,000,000)
Gross claim liability, net of all subrogation and discounts, before reinsurance	258,000,000	404,000,000
Less: Unearned premium reserves	(8,000,000)	(14,000,000)
Plus: Loss adjustment expenses reserves	2,000,000	4,000,000
Claim liability reported on Balance Sheet, before reinsurance	252,000,000	394,000,000
Reinsurance recoverable reported on Balance Sheet	$ 21,000,000	$ 22,000,000
IV [Member]
Schedule of Insured Financial Obligations with Credit Deterioration [Line Items]
Number of policies \| Policies	93	130
Remaining weighted-average contract period (in years)	12 years	13 years
Gross insured contractual payments outstanding:
Principal	$ 1,646,000,000	$ 2,759,000,000
Interest	565,000,000	1,284,000,000
Total	2,210,000,000	4,043,000,000
Gross undiscounted claim liability	729,000,000	1,423,000,000
Discount, gross claim liability	316,000,000	185,000,000
Gross claim liability before all subrogation and before reinsurance	413,000,000	1,238,000,000
Less:
Gross RMBS subrogation	(140,000,000)	(1,737,000,000)
Discount, RMBS subrogation	0	7,000,000
Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Rmbs Subrogation	(140,000,000)	(1,730,000,000)
Less:
Gross other subrogation	(172,000,000)	(583,000,000)
Discount, other subrogation	42,000,000	24,000,000
Discounted other subrogation, before reinsurance	(130,000,000)	(559,000,000)
Gross claim liability, net of all subrogation and discounts, before reinsurance	143,000,000	(1,051,000,000)
Less: Unearned premium reserves	(10,000,000)	(24,000,000)
Plus: Loss adjustment expenses reserves	4,000,000	40,000,000
Claim liability reported on Balance Sheet, before reinsurance	137,000,000	(1,036,000,000)
Reinsurance recoverable reported on Balance Sheet	$ 3,000,000	$ (11,000,000)
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	$ 34,000,000	$ 40,000,000
Interest	19,000,000	22,000,000
Total	53,000,000	62,000,000
Gross undiscounted claim liability	53,000,000	62,000,000
Discount, gross claim liability	9,000,000	4,000,000
Gross claim liability before all subrogation and before reinsurance	43,000,000	57,000,000
Less:
Gross RMBS subrogation	0	0
Discount, RMBS subrogation	0	0
Schedule Of Insured Financial Obligations With Credit Deterioration Reductions Of Gross Claim Liability Rmbs Subrogation	0	0
Less:
Gross other subrogation	(12,000,000)	(12,000,000)
Discount, other subrogation	4,000,000	2,000,000
Discounted other subrogation, before reinsurance	(8,000,000)	(10,000,000)
Gross claim liability, net of all subrogation and discounts, before reinsurance	35,000,000	47,000,000
Less: Unearned premium reserves	(1,000,000)	(1,000,000)
Plus: Loss adjustment expenses reserves	0	0
Claim liability reported on Balance Sheet, before reinsurance	34,000,000	46,000,000
Reinsurance recoverable reported on Balance Sheet	$ 0	$ 0

Financial Guarantee Insuranc_10

Financial Guarantee Insurance Contracts - Summary of Balance of RMBS Subrogation Recoveries and Related Claim Liabilities, by Estimation Approach (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Schedule Of Balance Of Rmbs Subrogation Recoveries And Related Claim Liabilities By Estimation Approach [Line Items]
Subrogation recoveries	$ 140	$ 1,730

Financial Guarantee Insuranc_11

Financial Guarantee Insurance Contracts - Summary of Rollforward of RMBS Subrogation, by Estimation Approach (Detail) $ in Millions	Dec. 31, 2022 USD ($)
Subrogation By Estimation Approach [Roll Forward]
Discounted RMBS subrogation (gross of reinsurance), beginning balance	$ 1,730
Changes recognized
Discounted RMBS subrogation (gross of reinsurance), ending balance	$ 140

Financial Guarantee Insuranc_12

Financial Guarantee Insurance Contracts - Estimated Future Amortization Expense for Insurance Intangible Asset (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Amortization Of Intangible Assets [Line Items]
Amortization of intangible assets	$ 47	$ 55	$ 57
2018	31
2019	29
2020	27
2021	25
2022	23
Thereafter	178
Intangible assets	$ 326	362
Insurance Intangible Asset [Member]
Amortization Of Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	7 years 3 months 18 days
Amortization of intangible assets	$ 44	52	$ 57
Intangible Assets, Gross (Excluding Goodwill)	1,247	1,278
2018	27
2019	25
2020	23
2021	21
2022	19
Thereafter	149
Finite-Lived Intangible Assets, Accumulated Amortization	981	958
Intangible assets	$ 266	$ 320

Financial Guarantee Insurance -

Financial Guarantee Insurance - Summary of Percentage Ceded to Reinsurers and Reinsurance Recoverable and Rating Levels (Detail)	Dec. 31, 2022
Summary of Ceded Par and Net Unsecured Reinsurance Recoverable [Line Items]
Percentage of Ceded Reinsurance Recoverable Represented by Top Three	84.20%

Financial Guarantee Insuranc_13

Financial Guarantee Insurance Contracts Financial Guarantee Insurance Contracts Earned Premiums by Geographic Location (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Premiums Earned, Net, Financial Guarantee Insurance Contracts	$ 56	$ 47	$ 54
Premiums Receivable, Gross	259	329
Liability for Claims and Claims Adjustment Expense	805	1,570
Subrogation recoverable	271	2,092
Property and Casualty, Commercial Insurance
Liability for Claims and Claims Adjustment Expense	90	32
Public Finance [Member]
Premiums Receivable, Gross	150	159
Structured Finance [Member]
Premiums Receivable, Gross	24	45
International Finance [Member]
Premiums Receivable, Gross	85	125
Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	148	157
Other Public Finance Sectors [Member] \| Public Finance [Member]
Premiums Receivable, Gross	2	2
Mortgage-backed and Home Equity [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	11	16
Student Loan [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	8	12
Structured Insurance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	10
Other Structured Finance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	4	7
Sovereign/Sub-sovereign [Member] \| International Finance [Member]
Premiums Receivable, Gross	64	93
Investor-owned and Public Utilities [Member] \| International Finance [Member]
Premiums Receivable, Gross	18	28
Other International [Member] \| International Finance [Member]
Premiums Receivable, Gross	2	5
Surveillance Category One [Member]
Premiums Receivable, Gross	217	277
Surveillance Category One [Member] \| Public Finance [Member]
Premiums Receivable, Gross	142	151
Surveillance Category One [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	5	19
Surveillance Category One [Member] \| International Finance [Member]
Premiums Receivable, Gross	70	107
Surveillance Category One [Member] \| Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	140	149
Surveillance Category One [Member] \| Other Public Finance Sectors [Member] \| Public Finance [Member]
Premiums Receivable, Gross	2	2
Surveillance Category One [Member] \| Mortgage-backed and Home Equity [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	1
Surveillance Category One [Member] \| Student Loan [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	1	1
Surveillance Category One [Member] \| Structured Insurance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	10
Surveillance Category One [Member] \| Other Structured Finance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	4	7
Surveillance Category One [Member] \| Sovereign/Sub-sovereign [Member] \| International Finance [Member]
Premiums Receivable, Gross	49	74
Surveillance Category One [Member] \| Investor-owned and Public Utilities [Member] \| International Finance [Member]
Premiums Receivable, Gross	18	28
Surveillance Category One [Member] \| Other International [Member] \| International Finance [Member]
Premiums Receivable, Gross	2	5
IA [Member]
Premiums Receivable, Gross	10	12
IA [Member] \| Public Finance [Member]
Premiums Receivable, Gross	3	3
IA [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	1	1
IA [Member] \| International Finance [Member]
Premiums Receivable, Gross	7	8
IA [Member] \| Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	3	3
IA [Member] \| Other Public Finance Sectors [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
IA [Member] \| Mortgage-backed and Home Equity [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
IA [Member] \| Student Loan [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	1	1
IA [Member] \| Structured Insurance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
IA [Member] \| Other Structured Finance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
IA [Member] \| Sovereign/Sub-sovereign [Member] \| International Finance [Member]
Premiums Receivable, Gross	7	8
IA [Member] \| Investor-owned and Public Utilities [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
IA [Member] \| Other International [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
II [Member]
Premiums Receivable, Gross	5	6
II [Member] \| Public Finance [Member]
Premiums Receivable, Gross	5	5
II [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	1
II [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
II [Member] \| Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	5	5
II [Member] \| Other Public Finance Sectors [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
II [Member] \| Mortgage-backed and Home Equity [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	1
II [Member] \| Student Loan [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
II [Member] \| Structured Insurance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
II [Member] \| Other Structured Finance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
II [Member] \| Sovereign/Sub-sovereign [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
II [Member] \| Investor-owned and Public Utilities [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
II [Member] \| Other International [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
III [Member]
Premiums Receivable, Gross	16	22
III [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
III [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	7	12
III [Member] \| International Finance [Member]
Premiums Receivable, Gross	9	11
III [Member] \| Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
III [Member] \| Other Public Finance Sectors [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
III [Member] \| Mortgage-backed and Home Equity [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	2
III [Member] \| Student Loan [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	7	9
III [Member] \| Structured Insurance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
III [Member] \| Other Structured Finance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
III [Member] \| Sovereign/Sub-sovereign [Member] \| International Finance [Member]
Premiums Receivable, Gross	9	11
III [Member] \| Investor-owned and Public Utilities [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
III [Member] \| Other International [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member]
Premiums Receivable, Gross	11	12
IV [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	11	12
IV [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Other Public Finance Sectors [Member] \| Public Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Mortgage-backed and Home Equity [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	11	12
IV [Member] \| Student Loan [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Structured Insurance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Other Structured Finance [Member] \| Structured Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Sovereign/Sub-sovereign [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Investor-owned and Public Utilities [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
IV [Member] \| Other International [Member] \| International Finance [Member]
Premiums Receivable, Gross	0	0
Reportable Geographical Components [Member] \| UNITED STATES
Premiums Earned, Net, Financial Guarantee Insurance Contracts	41	27	32
Reportable Geographical Components [Member] \| UNITED KINGDOM
Premiums Earned, Net, Financial Guarantee Insurance Contracts	13	14	24
Reportable Geographical Components [Member] \| Other International [Member]
Premiums Earned, Net, Financial Guarantee Insurance Contracts	$ 3	$ 6	$ (2)

Reinsurance

Reinsurance $ in Millions	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Insurance [Line Items]
Letters of Credit Outstanding, Amount	$ 116
Deferred Ceded Premiums And Reinsurance Recoverables	239
Reinsurance Payable	$ 39	$ 33
Percentage of Ceded Reinsurance Recoverable Represented by Top Three	84.20%
Reinsurance Recoverables, Gross	$ 115
Net unsecured reinsurance recoverable	60
Reinsurance Recoverable, Gross, All Other	18
Unsecured Reinsurance Recoverable, All Other	7
Reinsurance Recoverable Credit Exposure	60	32
Uncollateralized Credit Exposure Supoorted by Unlimited Uncapped Indemnity	$ 45	$ 30
Number of Reinsurers Covering Majority	3
QBE Insurance Corporation \| Property and Casualty, Commercial Insurance
Insurance [Line Items]
Reinsurance Recoverables, Gross	$ 41
Net unsecured reinsurance recoverable	41
Assured Guaranty Re Ltd [Member] \| Financial Guarantee
Insurance [Line Items]
Reinsurance Recoverables, Gross	30
Net unsecured reinsurance recoverable	0
General Reinsurance Company \| Property and Casualty, Commercial Insurance
Insurance [Line Items]
Reinsurance Recoverables, Gross	25
Net unsecured reinsurance recoverable	$ 11

Insurance Contracts (Details)

Insurance Contracts (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 06, 2022
Insurance [Abstract]
Amount of PRHTA Insured Exposure Fully Satisfied		$ 4
Amount of PRHTA Net Par Exposure Fully Satisfied		$ 83
Insurance [Line Items]
Percent of PRHTA Net Par Exposure Fully Satisfied		21%
Amount of Net Par Exposure Put in Trust and Consolidated by Ambac	$ 178	$ 312

Insurance Regulatory Restrict_2

Insurance Regulatory Restrictions Additional Details (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Average Annual Rate Of Return	3.22%	5.28%
Prescribed Discount Rate Percentage	5.10%
Minimum [Member]
Settlement Agreement Annual Restricted Payment Amount	$ 5
Maximum [Member]
Settlement Agreement Annual Restricted Payment Amount	8
Ambac Assurance [Member]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	598	$ 757
Ambac Assurance [Member] \| Prescribed Or Permitted Additional Accounting Practices [Member]
Statutory Accounting Practices, Prescribed Practice, Amount	90	(5)
Everspan Indemnity
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	107	$ 106
Everspan Indemnity \| Prescribed Or Permitted Additional Accounting Practices [Member]
Statutory Accounting Practices, Prescribed Practice, Amount	$ 18

Derivative Instruments - Summar

Derivative Instruments - Summary of Gross Fair Values of Individual Derivative Instruments (Detail) - USD ($)	Dec. 31, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 28,000,000	$ 76,000,000
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Net Amounts of Assets Presented in the Consolidated Balance Sheet, Derivative Assets	27,000,000	76,000,000
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet, Derivative Liabilities	38,000,000	95,000,000
Derivative Liabilities Gross Amount Of Collateral Cash And Securities Pledged Not Offset		93,000,000
Fair value of derivative liabilities	38,000,000
Net Amount, Derivative Assets	27,000,000	76,000,000
Net Amount, Derivative Liabilities	0	2,000,000
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	0	0
Derivative Liability, Fair Value, Gross Liability	38,000,000	95,000,000
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Derivative, Collateral, Obligation to Return Cash	0	0
Variable Interest Entity [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	239,000,000	38,000,000
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Net Amounts of Assets Presented in the Consolidated Balance Sheet, Derivative Assets	239,000,000	38,000,000
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet, Derivative Liabilities	1,048,000,000	1,940,000,000
Derivative Liabilities Gross Amount Of Collateral Cash And Securities Pledged Not Offset		0
Fair value of derivative liabilities	0
Net Amount, Derivative Assets	239,000,000	38,000,000
Net Amount, Derivative Liabilities	1,048,000,000	1,940,000,000
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	0	0
Derivative Liability, Fair Value, Gross Liability	1,048,000,000	1,940,000,000
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Other Credit Derivatives [Member]
Derivatives, Fair Value [Line Items]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet, Derivative Liabilities		0
Net Amount, Derivative Liabilities		0
Derivative Liability, Fair Value, Gross Liability		0
Derivative Liability, Fair Value, Amount Offset Against Collateral		0
Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	27,000,000	76,000,000
Derivative Asset, Fair Value, Amount Offset Against Collateral	0	0
Net Amounts of Assets Presented in the Consolidated Balance Sheet, Derivative Assets	27,000,000	76,000,000
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet, Derivative Liabilities	38,000,000	94,000,000
Fair value of derivative liabilities	38,000,000	93,000,000
Net Amount, Derivative Assets	27,000,000	76,000,000
Net Amount, Derivative Liabilities	0	1,000,000
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		0
Derivative Liability, Fair Value, Gross Liability	38,000,000	94,000,000
Derivative Liability, Fair Value, Amount Offset Against Collateral	0	0
Interest Rate Swaps [Member] \| Variable Interest Entity [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	190,000,000
Derivative Asset, Fair Value, Amount Offset Against Collateral	0
Net Amounts of Assets Presented in the Consolidated Balance Sheet, Derivative Assets	190,000,000
Net Amounts of Liabilities Presented in the Consolidated Balance Sheet, Derivative Liabilities	1,048,000,000	1,940,000,000
Net Amount, Derivative Assets	190,000,000
Net Amount, Derivative Liabilities	1,048,000,000	1,940,000,000
Derivative Liability, Fair Value, Gross Liability	1,048,000,000	1,940,000,000
Interest Rate Swaps [Member] \| Variable Interest Entity [Member] \| Level 3 [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0
Currency Swaps [Member] \| Variable Interest Entity [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	49,000,000	38,000,000
Derivative Asset, Fair Value, Amount Offset Against Collateral	0
Net Amounts of Assets Presented in the Consolidated Balance Sheet, Derivative Assets	49,000,000	38,000,000
Net Amount, Derivative Assets	49,000,000	38,000,000
Derivative Asset, Fair Value, Amount Not Offset Against Collateral		$ 0
Warrant [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,000,000
Net Amounts of Assets Presented in the Consolidated Balance Sheet, Derivative Assets	1,000,000
Net Amount, Derivative Assets	$ 1,000,000

Derivative Instruments - Additi

Derivative Instruments - Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Derivative, Net Liability Position, Aggregate Fair Value	$ 38	$ 93
Derivative, Collateral, Right to Reclaim Cash	6	13
Collateral Already Posted, Aggregate Fair Value	54	109
Variable Interest Entity, Primary Beneficiary [Member] \| Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	1,573	1,221
Variable Interest Entity, Primary Beneficiary [Member] \| Interest Rate Swap One [Member]
Derivative [Line Items]
Derivative, Notional Amount	887	1,069
Variable Interest Entity, Primary Beneficiary [Member] \| Currency Swaps [Member]
Derivative [Line Items]
Derivative, Notional Amount	176	272
AFS [Member] \| Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	337	185
AFS [Member] \| Interest Rate Swap One [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 989	$ 1,275

Derivative Instruments - Summ_2

Derivative Instruments - Summary of Location and Amount of Gains and Losses of Derivative Contracts (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 129	$ 22	$ (50)
Derivative, Gain (Loss) on Derivatives, Total Net	694	(128)	(193)
Net gains (losses) on derivative contracts [Domain] \| Credit Derivatives [Member]
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Net gains (losses) on derivative contracts [Domain] \| Interest Rate Swaps [Member]
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	65	13	(9)
Net gains (losses) on derivative contracts [Domain] \| Futures Contracts [Member]
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	62	9	(41)
Net gains (losses) on derivative contracts [Domain] \| Warrant [Member]
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1	0	0
Income Loss On Variable Interest Entities [Member] \| Variable Interest Entity [Member]
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	565	(150)	(144)
Income Loss On Variable Interest Entities [Member] \| Interest Rate Swaps [Member] \| Variable Interest Entity [Member]
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	541	(152)	(138)
Income Loss On Variable Interest Entities [Member] \| Currency Swaps [Member] \| Variable Interest Entity [Member]
Debt and Equity Securities, FV-NI [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 24	$ 2	$ (6)

Derivative Instruments - Summ_3

Derivative Instruments - Summary of Gross Principal Notional Outstanding for CDS Contracts (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Other Credit Derivatives [Member]
Ambac Rating
Derivative, Notional Amount	$ 0	$ 201
Variable Interest Entity [Member] \| Interest Rate Swap [Member]
Ambac Rating
Derivative, Notional Amount	1,573	1,221
Variable Interest Entity [Member] \| Interest Rate Swap One [Member]
Ambac Rating
Derivative, Notional Amount	887	1,069
Variable Interest Entity [Member] \| Currency Swaps [Member]
Ambac Rating
Derivative, Notional Amount	$ 176	$ 272

Derivative Instruments - Summ_4

Derivative Instruments - Summarize Information by Major Category of CDS Contracts (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Summary of information by major category of CDS contracts
Net derivative liabilities at fair value	$ 38
Other Credit Derivatives [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative, Notional Amount	$ 0	$ 201

Derivative Instruments - Summ_5

Derivative Instruments - Summary of Notional Amounts of AFS's Trading Derivative Products (Detail) - AFS [Member] - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Interest Rate Swaps [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative, Notional Amount	$ 337	$ 185
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, Notional Amount	989	1,275
US Treasury Securities
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative, Notional Amount	$ 0	$ 470

Derivative Instruments - Summ_6

Derivative Instruments - Summary of Notional for VIE Derivatives Outstanding (Detail) - Variable Interest Entity, Primary Beneficiary [Member] - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Interest Rate Swaps [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative, Notional Amount	$ 1,573	$ 1,221
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, Notional Amount	887	1,069
Currency Swaps [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative, Notional Amount	$ 176	$ 272

Financial Guarantee Insuranc_14

Financial Guarantee Insurance Contracts - Summary of Gross Premium Receivable Roll-Forward (Direct and Assumed Contracts) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Premiums Receivable, Gross	$ 259	$ 329
Public Finance [Member]
Premiums Receivable, Gross	150	159
Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	148	157
Surveillance Category One [Member]
Premiums Receivable, Gross	217	277
Surveillance Category One [Member] \| Public Finance [Member]
Premiums Receivable, Gross	142	151
Surveillance Category One [Member] \| Housing Revenue [Member] \| Public Finance [Member]
Premiums Receivable, Gross	$ 140	$ 149

Intangible Assets (Details)

Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 326	$ 362
Finite-Lived Intangible Assets, Net	312	353
2018	31
2019	29
2020	27
2021	25
2022	23
Thereafter	178
Amortization of intangible assets	47	55	$ 57
Goodwill	61	46
Goodwill, Acquired During Period	15
License
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	14	9
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	52	36
Finite-Lived Intangible Assets, Accumulated Amortization	6	3
Intangible assets	47	33
2018	4
2019	4
2020	4
2021	3
2022	3
Thereafter	$ 28
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	6 years 4 months 24 days
Amortization of intangible assets	$ 3	3	0
Insurance Intangible Asset [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	1,247	1,278
Finite-Lived Intangible Assets, Accumulated Amortization	981	958
Intangible assets	266	320
2018	27
2019	25
2020	23
2021	21
2022	19
Thereafter	$ 149
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	7 years 3 months 18 days
Amortization of intangible assets	$ 44	$ 52	$ 57

Variable Interest Entities - Ad

Variable Interest Entities - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($) Entity	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) Entity	Dec. 31, 2020 USD ($)
Variable Interest Entities [Line Items]
Fixed income securities, amortized cost	$ 2,041,000,000	$ 2,041,000,000	$ 2,041,000,000	$ 2,041,000,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	31,000,000	31,000,000	31,000,000	31,000,000	$ 141,000,000	$ 141,000,000	$ 141,000,000
Available-for-sale Securities	1,966,000,000	1,966,000,000	1,966,000,000	1,966,000,000
Restricted Cash	14,000,000	14,000,000	14,000,000	14,000,000	5,000,000	5,000,000	5,000,000	$ 13,000,000
Fair value of special purpose entities	0	0	0	0
Assets	7,973,000,000	7,973,000,000	7,973,000,000	7,973,000,000	12,303,000,000	12,303,000,000	12,303,000,000
Liabilities	6,647,000,000	6,647,000,000	6,647,000,000	6,647,000,000	11,187,000,000	11,187,000,000	11,187,000,000
Other Investments	568,000,000	568,000,000	568,000,000	568,000,000	690,000,000	690,000,000	690,000,000
Long-term debt	639,000,000	639,000,000	639,000,000	639,000,000	2,230,000,000	2,230,000,000	2,230,000,000
Derivative assets	27,000,000	27,000,000	27,000,000	27,000,000	76,000,000	76,000,000	76,000,000
Other assets	84,000,000	84,000,000	84,000,000	84,000,000	68,000,000	68,000,000	68,000,000
Accrued interest payable	427,000,000	427,000,000	427,000,000	427,000,000	576,000,000	576,000,000	576,000,000
Derivative liabilities	38,000,000	38,000,000	38,000,000	38,000,000	95,000,000	95,000,000	95,000,000
Other liabilities	163,000,000	163,000,000	$ 163,000,000	$ 163,000,000	133,000,000	$ 133,000,000	$ 133,000,000
Variable Interest Entity, Initial Consolidation, Gain (Loss)		37,000,000			0			$ 0
Number of DeConsolidated Variable Interest Entities			0			0		0
Consolidated Entities [Member]
Variable Interest Entities [Line Items]
Number of consolidated Variable Interest Entities			3	9		0	6
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Available-for-sale Securities	1,967,000,000	1,967,000,000	$ 1,967,000,000	$ 1,967,000,000	3,455,000,000	$ 3,455,000,000	$ 3,455,000,000
Restricted Cash	17,000,000	17,000,000	17,000,000	17,000,000	2,000,000	2,000,000	2,000,000	$ 2,000,000
Assets	4,054,000,000	4,054,000,000	4,054,000,000	4,054,000,000	6,216,000,000	6,216,000,000	6,216,000,000
Liabilities	4,160,000,000	4,160,000,000	4,160,000,000	4,160,000,000	6,156,000,000	6,156,000,000	6,156,000,000
Loans, Unpaid principal balance	1,977,000,000	1,977,000,000	1,977,000,000	1,977,000,000	2,363,000,000	2,363,000,000	2,363,000,000
Long-term Debt, Fair Value	2,788,000,000	2,788,000,000	2,788,000,000	2,788,000,000	4,056,000,000	4,056,000,000	4,056,000,000
Long-term debt, Unpaid principal balance	3,064,000,000	3,064,000,000	3,064,000,000	3,064,000,000	3,579,000,000	3,579,000,000	3,579,000,000
Long-term debt	3,107,000,000	3,107,000,000	3,107,000,000	3,107,000,000	4,216,000,000	4,216,000,000	4,216,000,000
Financing Receivable, after Allowance for Credit Loss	1,829,000,000	1,829,000,000	1,829,000,000	1,829,000,000	2,718,000,000	2,718,000,000	2,718,000,000
Derivative assets	239,000,000	239,000,000	239,000,000	239,000,000	38,000,000	38,000,000	38,000,000
Other assets	2,000,000	2,000,000	2,000,000	2,000,000	2,000,000	2,000,000	2,000,000
Long-term Debt, at par less amortized discount	319,000,000	319,000,000	319,000,000	319,000,000	160,000,000	160,000,000	160,000,000
Derivative liabilities	1,048,000,000	1,048,000,000	1,048,000,000	1,048,000,000	1,940,000,000	1,940,000,000	1,940,000,000
Other liabilities	5,000,000	5,000,000	5,000,000	$ 5,000,000	0	0	$ 0
Ambac UK [Member] \| Consolidated Entities [Member]
Variable Interest Entities [Line Items]
Number of consolidated Variable Interest Entities \| Entity				5			5
Ambac UK [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Available-for-sale Securities	1,828,000,000	1,828,000,000	1,828,000,000	$ 1,828,000,000	3,320,000,000	3,320,000,000	$ 3,320,000,000
Restricted Cash	1,000,000	1,000,000	1,000,000	1,000,000	1,000,000	1,000,000	1,000,000
Assets	3,896,000,000	3,896,000,000	3,896,000,000	3,896,000,000	6,077,000,000	6,077,000,000	6,077,000,000
Liabilities	3,836,000,000	3,836,000,000	3,836,000,000	3,836,000,000	5,996,000,000	5,996,000,000	5,996,000,000
Long-term Debt, Fair Value	2,788,000,000	2,788,000,000	2,788,000,000	2,788,000,000	4,056,000,000	4,056,000,000	4,056,000,000
Long-term debt	2,788,000,000	2,788,000,000	2,788,000,000	2,788,000,000	4,056,000,000	4,056,000,000	4,056,000,000
Financing Receivable, after Allowance for Credit Loss	1,829,000,000	1,829,000,000	1,829,000,000	1,829,000,000	2,718,000,000	2,718,000,000	2,718,000,000
Derivative assets	239,000,000	239,000,000	239,000,000	239,000,000	38,000,000	38,000,000	38,000,000
Other assets	0	0	0	0	0	0	0
Long-term Debt, at par less amortized discount	0	0	0	0	0	0	0
Derivative liabilities	1,048,000,000	1,048,000,000	1,048,000,000	1,048,000,000	1,940,000,000	1,940,000,000	1,940,000,000
Other liabilities	0	0	0	$ 0	0	0	$ 0
Ambac Assurance [Member] \| Consolidated Entities [Member]
Variable Interest Entities [Line Items]
Number of consolidated Variable Interest Entities \| Entity				4			1
Ambac Assurance [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Available-for-sale Securities	139,000,000	139,000,000	139,000,000	$ 139,000,000	136,000,000	136,000,000	$ 136,000,000
Restricted Cash	16,000,000	16,000,000	16,000,000	16,000,000	1,000,000	1,000,000	1,000,000
Assets	157,000,000	157,000,000	157,000,000	157,000,000	139,000,000	139,000,000	139,000,000
Liabilities	324,000,000	324,000,000	324,000,000	324,000,000	160,000,000	160,000,000	160,000,000
Long-term Debt, Fair Value	0	0	0	0	0	0	0
Long-term debt	319,000,000	319,000,000	319,000,000	319,000,000	160,000,000	160,000,000	160,000,000
Financing Receivable, after Allowance for Credit Loss	0	0	0	0	0	0	0
Derivative assets	0	0	0	0	0	0	0
Other assets	2,000,000	2,000,000	2,000,000	2,000,000	2,000,000	2,000,000	2,000,000
Long-term Debt, at par less amortized discount	319,000,000	319,000,000	319,000,000	319,000,000	160,000,000	160,000,000	160,000,000
Derivative liabilities	0	0	0	0	0	0	0
Other liabilities	5,000,000	5,000,000	5,000,000	5,000,000	0	0	0
Ambac Assurance Corporation [Member]
Variable Interest Entities [Line Items]
Long-term debt	$ 639,000,000	639,000,000	639,000,000	639,000,000	2,230,000,000	2,230,000,000	2,230,000,000
Ambac Assurance Corporation [Member] \| 5.1% Junior Surplus Notes, General Account Due 2020 [Member] \| Corolla Notes
Variable Interest Entities [Line Items]
Note Holders	1
Corporate Debt Securities [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Available-for-sale Securities	$ 1,828,000,000	1,828,000,000	1,828,000,000	1,828,000,000	3,320,000,000	3,320,000,000	3,320,000,000
Corporate Debt Securities [Member] \| Ambac UK [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Available-for-sale Securities	1,828,000,000	1,828,000,000	1,828,000,000	1,828,000,000	3,320,000,000	3,320,000,000	3,320,000,000
Corporate Debt Securities [Member] \| Ambac Assurance [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Available-for-sale Securities	0	0	0	0	0	0	0
Municipal Bonds [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,000,000	1,000,000	1,000,000	1,000,000	29,000,000	29,000,000	29,000,000
Available-for-sale Securities	96,000,000	96,000,000	96,000,000	96,000,000	136,000,000	136,000,000	136,000,000
Municipal Bonds [Member] \| Ambac UK [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Available-for-sale Securities	0	0	0	0	0	0	0
Municipal Bonds [Member] \| Ambac Assurance [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Available-for-sale Securities	$ 96,000,000	$ 96,000,000	$ 96,000,000	$ 96,000,000	$ 136,000,000	$ 136,000,000	$ 136,000,000

Variable Interest Entities - Su

Variable Interest Entities - Summary of Fair Value of Fixed Income Securities, by Asset-Type, Held by Consolidated Variable Interest Entities (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Variable Interest Entities [Line Items]
Variable Interest Entity Nonconsolidated Carrying Amount Insurance Assets	$ 490	$ 2,195
Variable Interest Entity Nonconsolidated Carrying Amount Insurance Liabilities	840	1,023
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	21,639	25,112
Variable Interest Entity Nonconsolidated Carrying Amount Derivative Net Assets Or Liabilities	1
Fixed income securities, amortized cost	2,041
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	31	141
Variable Interest Entity [Member]
Variable Interest Entities [Line Items]
Variable Interest Entity Nonconsolidated Carrying Amount Derivative Net Assets Or Liabilities		5
Municipal Bonds [Member] \| Variable Interest Entity [Member]
Variable Interest Entities [Line Items]
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	$ 1	$ 29

Variable Interest Entities - _2

Variable Interest Entities - Supplemental Information about Loans Held as Assets and Long-Term Debt Associated with Consolidated Variable Interest Entities (Detail) - Variable Interest Entity [Member] - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Variable Interest Entities [Line Items]
Long-term Debt, Fair Value	$ 2,788	$ 4,056
Loans, Unpaid principal balance	1,977	2,363
Long-term debt, Unpaid principal balance	$ 3,064	$ 3,579

Variable Interest Entities - _3

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 (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Variable Interest Entities [Line Items]
Maximum Exposure To Loss	$ 21,639	$ 25,112
Insurance Assets	490	2,195
Insurance Liabilities	840	1,023
Derivative Liabilities	1
Variable Interest Entity [Member]
Variable Interest Entities [Line Items]
Derivative Liabilities		5
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, before Tax	(1)	5	$ (3)
Global Structured Finance [Member]
Variable Interest Entities [Line Items]
Maximum Exposure To Loss	3,642	4,879
Insurance Assets	274	1,949
Insurance Liabilities	628	765
Derivative Liabilities	1	5
Global Structured Finance [Member] \| Residential Mortgage-Backed Securities [Member]
Variable Interest Entities [Line Items]
Maximum Exposure To Loss	2,559	3,265
Insurance Assets	266	1,929
Insurance Liabilities	400	521
Derivative Liabilities	0	0
Global Structured Finance [Member] \| Other Consumer Asset-Backed [Member]
Variable Interest Entities [Line Items]
Maximum Exposure To Loss	652	788
Insurance Assets	6	17
Insurance Liabilities	225	234
Derivative Liabilities	0	0
Global Structured Finance [Member] \| Other Debt Obligations [Member]
Variable Interest Entities [Line Items]
Maximum Exposure To Loss	430	826
Insurance Assets	2	3
Insurance Liabilities	2	10
Derivative Liabilities	1	5
Global Public Finance [Member]
Variable Interest Entities [Line Items]
Maximum Exposure To Loss	17,997	20,233
Insurance Assets	216	246
Insurance Liabilities	212	257
Derivative Liabilities	$ 0	$ 0

Variable Interest Entities Vari

Variable Interest Entities Variable Interest Entity - Change in Fair Value of Assets and Liabilities (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Fixed income securities, amortized cost	$ 2,041
Long-term debt	639	$ 2,230
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	31	141
Variable Interest Entity Change in Fair Value of Assets and Liabilities	0	4	$ (1)
Realized Investment Gains (Losses)	31	7	22
Variable Interest Entity, Initial Consolidation, Gain (Loss)	37	0	0
Variable Interest Entity, Measure of Activity, Income or Loss before Tax	21	7	$ 5
Assets	7,973	12,303
Liabilities	$ 6,647	$ 11,187
Number of DeConsolidated Variable Interest Entities	0	0	0
Variable Interest Entity [Member]
Long-term debt	$ 3,107	$ 4,216
Loans, Unpaid principal balance	1,977	2,363
Long-term debt, Unpaid principal balance	3,064	3,579
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, before Tax	(1)	1	$ (1)
Interest Expense, Long-term Debt	(12)	(6)	(6)
Other Expenses	(1)	(1)	0
Assets	4,054	6,216
Liabilities	4,160	6,156
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, before Tax	(1)	5	(3)
Variable Interest Entity [Member] \| Available-for-sale Securities [Member]
Gross Investment Income, Operating	(4)	6	7
Realized Investment Gains (Losses)	$ 2	$ 2	$ 8

Variable Interest Entities Va_2

Variable Interest Entities Variabile Interest Entities - Carry Value of Secured Notes from LSNI (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Long-term debt	$ 639	$ 2,230
Ambac Assurance Corporation [Member]
Long-term debt	$ 639	$ 2,230

Variable Interest Entities Spec

Variable Interest Entities Special Purpose Entities, including Variable Interest Entities - Summary of Assets and Liabilities (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($) Entity	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) Entity	Dec. 31, 2020 USD ($)
Available-for-sale Securities, Amortized Cost Basis	$ 2,041	$ 2,041	$ 2,140	$ 2,140
Available-for-sale Securities	1,966	1,966
Restricted Cash	14	14	5	5	$ 13
Derivative assets	27	27	76	76
Other assets	84	84	68	68
Assets	7,973	7,973	12,303	12,303
Accrued interest payable	427	427	576	576
Long-term debt	639	639	2,230	2,230
Derivative liabilities	38	38	95	95
Other liabilities	163	163	133	133
Liabilities	6,647	6,647	11,187	11,187
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	106	106	16	16
Variable Interest Entity [Member]
Available-for-sale Securities	1,967	1,967	3,455	3,455
Restricted Cash	17	17	2	2	$ 2
Loans, at fair value	1,829	1,829	2,718	2,718
Derivative assets	239	239	38	38
Other assets	2	2	2	2
Assets	4,054	4,054	6,216	6,216
Long-term Debt	2,788	2,788	4,056	4,056
Long-term Debt, at par less amortized discount	319	319	160	160
Long-term debt	3,107	3,107	4,216	4,216
Derivative liabilities	1,048	1,048	1,940	1,940
Other liabilities	5	5	0	0
Liabilities	4,160	4,160	6,156	6,156
Loans, Unpaid principal balance	1,977	1,977	2,363	2,363
Long-term debt, Unpaid principal balance	3,064	3,064	3,579	3,579
Variable Interest Entity [Member] \| Ambac UK [Member]
Available-for-sale Securities	1,828	1,828	3,320	3,320
Restricted Cash	1	1	1	1
Loans, at fair value	1,829	1,829	2,718	2,718
Derivative assets	239	239	38	38
Other assets	0	0	0	0
Assets	3,896	3,896	6,077	6,077
Long-term Debt	2,788	2,788	4,056	4,056
Long-term Debt, at par less amortized discount	0	0	0	0
Long-term debt	2,788	2,788	4,056	4,056
Derivative liabilities	1,048	1,048	1,940	1,940
Other liabilities	0	0	0	0
Liabilities	3,836	3,836	5,996	5,996
Variable Interest Entity [Member] \| Ambac Assurance [Member]
Available-for-sale Securities	139	139	136	136
Restricted Cash	16	16	1	1
Loans, at fair value	0	0	0	0
Derivative assets	0	0	0	0
Other assets	2	2	2	2
Assets	157	157	139	139
Long-term Debt	0	0	0	0
Long-term Debt, at par less amortized discount	319	319	160	160
Long-term debt	319	319	160	160
Derivative liabilities	0	0	0	0
Other liabilities	5	5	0	0
Liabilities	324	324	160	160
Variable Interest Entity [Member] \| Corporate Debt Securities [Member]
Available-for-sale Securities	1,828	1,828	3,320	3,320
Variable Interest Entity [Member] \| Corporate Debt Securities [Member] \| Ambac UK [Member]
Available-for-sale Securities	1,828	1,828	3,320	3,320
Variable Interest Entity [Member] \| Corporate Debt Securities [Member] \| Ambac Assurance [Member]
Available-for-sale Securities	0	0	0	0
Variable Interest Entity [Member] \| Municipal Bonds [Member]
Available-for-sale Securities, Amortized Cost Basis	99	99	106	106
Available-for-sale Securities	96	96	136	136
Debt Securities, Trading	43	43	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(4)	(4)
Variable Interest Entity [Member] \| Municipal Bonds [Member] \| Ambac UK [Member]
Available-for-sale Securities	0	0	0	0
Debt Securities, Trading	0	0	0	0
Variable Interest Entity [Member] \| Municipal Bonds [Member] \| Ambac Assurance [Member]
Available-for-sale Securities	96	96	136	136
Debt Securities, Trading	$ 43	$ 43	$ 0	$ 0
Consolidated Entities [Member]
Number of consolidated Variable Interest Entities	3	9	0	6
Consolidated Entities [Member] \| Ambac UK [Member]
Number of consolidated Variable Interest Entities \| Entity		5		5
Consolidated Entities [Member] \| Ambac Assurance [Member]
Number of consolidated Variable Interest Entities \| Entity		4		1

Long-Term Debt (Details)

Long-Term Debt (Details) - USD ($) $ in Millions	12 Months Ended
Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Feb. 12, 2018
Debt Instrument [Line Items]
Tier 2 Note Security in RMBS Litigation Settlement Proceeds				$ 1,600
Long-term debt	$ 639	$ 2,230
Debt Instrument, Interest Rate, Effective Percentage	7%
Net realized gains on extinguishment of debt	$ 81	33	$ 0
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	665
Long-term Debt, Maturities, Repayments of Principal in Year Two	0
Long-term Debt, Maturities, Repayments of Principal in Year Three	0
Long-term Debt, Maturities, Repayments of Principal in Year Four	0
Long-term Debt, Maturities, Repayments of Principal in Year Five	0
Paydown of Ambac Note		1,641	$ 121
Long-term Debt, Maturities, Repayments of Principal after Year Five	$ 41
Tier 2 Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	8.50%
Debt Instrument, Interest Rate, Effective Percentage	9.90%
Debt Instrument, Face Amount	$ 146
Paid-in-Kind Interest	$ 49	93
Sitka AAC Note
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	5.70%
Ambac Assurance Corporation [Member]
Debt Instrument [Line Items]
Long-term debt	$ 639	2,230
Long-term Debt, Gross	706	2,334
Debt Instrument, Unamortized Discount (Premium), Net	(67)	(104)
Ambac Assurance Corporation [Member] \| Tier 2 Notes [Member]
Debt Instrument [Line Items]
Long-term debt	146	333
Long-term Debt, Gross	146	333
Debt Instrument, Unamortized Discount (Premium), Net	0	0
Ambac Assurance Corporation [Member] \| 5.1% Surplus Notes, General Account, Due 2020 [Member]
Debt Instrument [Line Items]
Long-term debt	477	729
Long-term Debt, Gross	519	785
Debt Instrument, Unamortized Discount (Premium), Net	(42)	(56)
Net realized gains on extinguishment of debt	33
Ambac Assurance Corporation [Member] \| Sitka AAC Note
Debt Instrument [Line Items]
Long-term debt	0	1,154
Debt Instrument, Unamortized Discount (Premium), Net	0	(21)
Debt Instrument, Face Amount	0	1,175
Net realized gains on extinguishment of debt	$ 53
Ambac UK [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0%
Long-term debt	$ 16	15
Long-term Debt, Gross	41	41
Debt Instrument, Unamortized Discount (Premium), Net	$ (25)	$ (26)
Debt Instrument, Interest Rate, Effective Percentage	7.40%
5.1 % Surplus Notes Due 2020 [Member] \| Ambac Assurance Corporation [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.10%	5.10%
5.1% Surplus Notes, General Account, Due 2020 [Member]
Debt Instrument [Line Items]
Net realized gains on extinguishment of debt	$ (134)
Debt Instrument, Repurchased During Period	266
Consolidated Variable Interest Entities [Member]
Debt Instrument [Line Items]
Unpaid Principal Amount Of Fixed Rate Debt Accounted For Under Fair Value Option	3,388	$ 3,739
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	0
Long-term Debt, Maturities, Repayments of Principal in Year Two	0
Long-term Debt, Maturities, Repayments of Principal in Year Three	26
Long-term Debt, Maturities, Repayments of Principal in Year Four	0
Long-term Debt, Maturities, Repayments of Principal in Year Five	0
Long-term Debt, Maturities, Repayments of Principal after Year Five	$ 3,362
Consolidated Variable Interest Entities [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	0%	0%
Consolidated Variable Interest Entities [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	7.93%	7.93%
London Interbank Offered Rate (LIBOR) [Member] \| Sitka AAC Note
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	4.50%
London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member] \| Sitka AAC Note
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	0.75%

Revenue from Contract with Cu_3

Revenue from Contract with Customer (Details) $ in Millions	12 Months Ended
Revenue from Contract with Customer (Details) $ in Millions	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract with Customer, Asset, after Allowance for Credit Loss	$ 5	$ 4
Contract with Customer, Liability	1	1
Contract with Customer, Liability, Revenue Recognized	1
Contract with Customer, Receivable, after Allowance for Credit Loss	7	2
Revenue from Contract with Customer, Excluding Assessed Tax	31	26
Contract with Customer, Performance Obligation Satisfied in Previous Period	6
Employer Stop Loss
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	9	8
Affinity Products
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	19	$ 18
AllTrans & Capacity Marine
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 3
Minimum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Employee Stop Loss Time When Base Commissions Recognized Begin and End In Months	17
Maximum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Employee Stop Loss Time When Base Commissions Recognized Begin and End In Months	20

Comprehensive Income - Schedule

Comprehensive Income - Schedule of Changes in Balances of Each Component of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ 58	$ 79
Other comprehensive income before reclassifications	296	13
Amounts reclassified from accumulated other comprehensive income	(15)	(9)
Income Tax Expense (Benefit)	(2)	(18)	$ 3
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(310)	(21)
Ending Balance	(253)	58	79
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	154	166
Other comprehensive income before reclassifications	211	5
Amounts reclassified from accumulated other comprehensive income	(14)	(7)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(225)	(12)
Ending Balance	(71)	154	166
Accumulated Translation Adjustment [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(100)	(92)
Other comprehensive income before reclassifications	85	8
Amounts reclassified from accumulated other comprehensive income	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(85)	(8)
Ending Balance	(184)	(100)	(92)
Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(1)	0
Other comprehensive income before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income	0	(1)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0	(1)
Ending Balance	(1)	(1)	0
Other Postretirement Benefits Plan [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	4	5
Other comprehensive income before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income	(1)	(1)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(1)	(1)
Ending Balance	$ 3	$ 4	$ 5

Comprehensive Income - Schedu_2

Comprehensive Income - Schedule of Amounts Reclassed Out of Each Component of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)	$ (2)	$ (18)	$ 3
Net of tax and noncontrolling interest	525	(28)	$ (437)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(15)	(9)
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized investment gains	(17)	(7)
Net of tax and noncontrolling interest	(14)	(7)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(14)	(7)
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)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	(1)
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Arising During Period, before Tax	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	(15)	(9)
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)	(3)	1
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
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	(1)	(1)
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
Prior service cost	(1)	(1)
Actuarial gains (losses)	0	0
Total before tax	(1)	(1)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ (1)	$ (1)

Net Income Per Share - Addition

Net Income Per Share - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	May 05, 2022	Mar. 29, 2022	Jun. 30, 2017	Nov. 02, 2016	May 01, 2013	Apr. 30, 2013
Schedule Of Earnings Per Share [Line Items]
Common Stock, Shares, Outstanding	44,973,757
Class of Warrant or Right, Outstanding	4,877,617
Number of new common stock issued	46,658,990	46,477,068
Common Stock, Par or Stated Value Per Share									$ 0.01
Exercise price of common stock								$ 16.67
Warrant exercised	0	132	34
Stock Issued During Period, Shares, New Issues	0	4	8
First Warrant Buyback Authorization Dollars						$ 10
SecondWarrantBuyBackAuthorizedDollars							$ 10
RemainingWarrantBuyBackAuthorizedDollars	$ 12
Net Income (Loss) Available to Common Stockholders, Basic	525	$ (28)	$ (437)
Noncontrolling Interest, Change in Redemption Value	$ 3	$ (12)
Stock Repurchase Program, Authorized Amount				$ 15	$ 20
Stock Repurchased During Period, Shares	1,605,316
Payments for Repurchase of Common Stock	$ 14.2
Common Stock Repurchase
Schedule Of Earnings Per Share [Line Items]
Common Stock Remaining Repurchase Dollar Amount				$ 20.8
Payments for Common Stock per share	$ 8.86
Common Stock [Member]
Schedule Of Earnings Per Share [Line Items]
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture	(1,330,382)

Net Income Per Share - Reconcil

Net Income Per Share - Reconciliation of Common Shares Used for Basic and Diluted Earnings Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of common shares and potential dilutive shares used for diluted earnings per share	46,414,830	46,535,001	46,147,062
Weighted Average Number of Shares Outstanding, Basic	45,719,906	46,535,001	46,147,062
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	4,877,617	4,877,653	4,877,754
Share-based Payment Arrangement, Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	0	16,121
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	177,119	475,333	302,145
Performance Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	700,915	1,002,501
Warrant [Member]
Effect of potential dilutive shares:
Effect of potential dilutive shares	0	0	0
Share-based Payment Arrangement, Option [Member]
Effect of potential dilutive shares:
Effect of potential dilutive shares	0	0	0
Performance Shares [Member]
Effect of potential dilutive shares:
Effect of potential dilutive shares	550,730	0	0
Restricted Stock Units (RSUs) [Member]
Effect of potential dilutive shares:
Effect of potential dilutive shares	144,194	0	0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2022	Dec. 31, 2021
Tax Credit Carryforward [Line Items]
Deferred Tax Liabilities, Net		$ 15,000	$ 28,000
Impact of AMT Repeal on Current Taxes	$ 29,581
Net Impact of New Tax Law	$ 1,886
NOL allocated amount		3,454,000
AFG [Member]
Tax Credit Carryforward [Line Items]
NOL allocated amount		$ 1,630,000
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, 2043

Income Taxes - Significant Port

Income Taxes - Significant Portions of Deferred Tax Liabilities and Deferred Tax Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Schedule of Deferred Income Tax Assets and Liabilities [Line Items]
Deferred Tax Assets, Net of Valuation Allowance	$ 70	$ 106
Deferred tax assets:
Net operating loss and capital carryforward	725	736
Deferred Tax Asset, Interest Carryforward	66	50
Deferred Tax Assets, Investments	6
Loss reserves	38	180
Deferred Tax Assets, Operating Loss Carryforwards, State and Local	8	7
Deferred Tax Assets, Debentures	15	7
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation	6	8
Other	4	4
Sub total deferred tax assets	867	993
Valuation allowance	796	886
Insurance intangible	56	67
Variable interest entities	4	15
Investments		14
Unearned premiums and credit fees	24	32
Other	1	6
Deferred Tax Liabilities, Gross	85	134
Deferred Tax Liabilities, Net	$ 15	$ 28

Income Taxes Income Taxes - Pro

Income Taxes Income Taxes - Provision for Income Taxes Charged To Income From Continuing Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Provision for Income Taxes [Line Items]
Current Income Tax Expense (Benefit)	$ 6	$ 12	$ 8
Deferred Income Tax Expense (Benefit)	(4)	6	(10)
Income tax expense (benefit)	2	18	(3)
Deferred Foreign Income Tax Expense (Benefit)	(4)	6	(10)
Current State and Local Tax Expense (Benefit)	0	2	0
Current Foreign Tax Expense (Benefit)	$ 7	$ 10	$ 8

Income Taxes Income Taxes - Eff

Income Taxes Income Taxes - Effect of Income Taxes on Net Income and Stockholders' Equity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Expense (Benefit) [Roll Forward]
Income tax expense (benefit)	$ 2	$ 18	$ (3)
Net Unrealized Losses On Securities Tax Effect	(47)	(3)	3
Valuation Allowances And Reserves Charged To Equity	41	1	3
Income Tax Effects Allocated Directly to Equity	(6)	(2)	1
Change in retirement benefits Tax Effect	0	0	0
Credit Risk Changes to Fair Value Options Tax Effect	0	0	0
Income Tax Effects Allocated Directly to Equity, Other	$ (4)	$ 16	$ (1)

Income Taxes Income Taxes - E_2

Income Taxes Income Taxes - Effective Tax Rates Differing From Prevailing Federal Corporate Income Tax Rates (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of Effective Tax Rates [Line Items]
Tax on income from continuing operations at statutory rate	$ 110	$ 0	$ (92)
Tax on income from continuing operations at statutory rate,tax rate	21%	21%	21%
Tax-exempt interest	$ (1)	$ (2)	$ (2)
Tax-exempt interest, tax rate	0%	(114.00%)	0%
Derivative, Gain (Loss) on Derivative, Net	$ 129	$ 22	$ (50)
Valuation allowance	$ (131)	$ (4)	$ 113
Valuation allowance, tax rate	(25.00%)	(230.00%)	(26.00%)
Other, net	$ (4)	$ 1	$ 2
Foreign taxes	$ 4	$ 8	$ 6
Foreign taxes, tax rate	1%	448%	(1.00%)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	$ (1)	$ 14	$ 0
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	0%	794%	0%
Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Amount			$ (29)
Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Percent			7%
Other, net, tax rate	(1.00%)	72%	0%
Income tax expense (benefit)	$ 2	$ 18	$ (3)
Effective Income Tax Rate Reconciliation, Percent	1%	991%	1%
Variable Interest Entity, Primary Beneficiary [Member] \| Income Loss On Variable Interest Entities [Member]
Reconciliation of Effective Tax Rates [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 565	$ (150)	$ (144)
Variable Interest Entity, Primary Beneficiary [Member] \| Currency Swaps [Member] \| Income Loss On Variable Interest Entities [Member]
Reconciliation of Effective Tax Rates [Line Items]
Derivative, Gain (Loss) on Derivative, Net	24	2	(6)
Variable Interest Entity, Primary Beneficiary [Member] \| Interest Rate Swaps [Member] \| Income Loss On Variable Interest Entities [Member]
Reconciliation of Effective Tax Rates [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 541	$ (152)	$ (138)

Income Taxes Income Taxes - Rec

Income Taxes Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) $ in Millions	Dec. 31, 2022 USD ($)
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	$ 0

Income Taxes Income Taxes - NOL

Income Taxes Income Taxes - NOL Usage Table (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2022	Dec. 31, 2021
Net Income Loss Reconciliation [Line Items]
Impact of AMT Repeal on Current Taxes		$ 29,581
Change in Impact of AMT Repeal on Current Taxes	$ 1,902
AMT Related to Filing of 2017 Tax Return		5,536
AMT Receivable Resulting from TCJA				$ 37,019
Net Impact of New Tax Law		$ 1,886
NOL allocated amount			$ 3,454,000
Amount of NOL Utilized to Trigger Payment to IRS			2,142,000
Ambac Assurance [Member]
Net Income Loss Reconciliation [Line Items]
NOL allocated amount			1,824,000
AFG [Member]
Net Income Loss Reconciliation [Line Items]
NOL allocated amount			$ 1,630,000
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, 2043
Potential Tolling Payment From AAC to IRS			$ 8,000

Income Taxes Schedule of Income

Income Taxes Schedule of Income Before Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Income Before Income Tax, Domestic and Foreign [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Domestic	$ 511	$ (32)	$ (441)
Income (Loss) from Continuing Operations before Income Taxes, Foreign	13	34	1
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	$ 525	$ 2	$ (440)

Income Taxes Impact of New Tax

Income Taxes Impact of New Tax Legislation (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2021
AMT Receivable Resulting from TCJA			$ 37,019
Change in Impact of AMT Repeal on Current Taxes	$ 1,902
Impact of AMT Repeal on Current Taxes		$ 29,581
AMT Related to Filing of 2017 Tax Return		$ 5,536

Employment Benefit Plans Postre

Employment Benefit Plans Postretirement Health Care and Other Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Postemployment Benefits, Period Expense	$ 2	$ 1	$ 1
Unfunded Accumulated Postretirement Benefit Obligations Determined By Company	$ 11
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	5%	2.75%
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	$ 0
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	0
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	0
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	0
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	1
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	3
Defined Benefit Plan, Benefit Obligation	$ 5
Maximum [Member]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year	5.50%
Minimum [Member]
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year	4.50%

Employment Benefit Plans Saving

Employment Benefit Plans Savings Plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	2%
Defined Contribution Plan, Cost	$ 1	$ 1	$ 1
Xchange
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	4%
Minimum [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	100%
Maximum [Member]
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	50%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	3%

Employment Benefit Plans Stock

Employment Benefit Plans Stock Compensation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense	$ 17	$ 14	$ 11
Total stock-based compensation (after-tax)	$ 17	$ 14	11
Common stock, shares authorized	130,000,000	130,000,000
2013 Plan
Share-based compensation expense [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	4,000,000
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	4,000,000
2021 Plan
Share-based compensation expense [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	1,475,000
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	1,475,000
Minimum [Member]
Share-based compensation expense [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	74,907
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	74,907
Maximum [Member]
Share-based compensation expense [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,145,243
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,145,243
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense	$ 5	$ 5	3
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense	12	10	8
Retained Earnings [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense	$ 0	$ 0	$ 0

Employment Benefit Plans Restri

Employment Benefit Plans Restricted Stock Units (Details)	12 Months Ended
Employment Benefit Plans Restricted Stock Units (Details)	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payment, Tax Withholding, Share-based Payment Arrangement \| $	$ 4,000,000	$ 6,000,000	$ 3,000,000
Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Restricted Stock Units Vested Number	385,087	332,306
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	504,764
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	538,163	504,764
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payment, Tax Withholding, Share-based Payment Arrangement \| $	$ 97,871
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	837,070
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	352,141
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	263,505
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(2,456)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	923,250	837,070
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value \| $ / shares	$ 17.82
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value \| $ / shares	12.48	$ 17.39	$ 17.36
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value \| $ / shares	17.13
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value \| $ / shares	15.65
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value \| $ / shares	$ 15.94	$ 17.82
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized \| $	$ 4,000,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	1 year 7 months 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value \| $	$ 4,000,000	$ 4,000,000	$ 4,000,000
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payment, Tax Withholding, Share-based Payment Arrangement \| $	$ 157,377
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	722,056
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	529,285
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(422,620)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(7,361)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	918,951	722,056
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value \| $ / shares	$ 18.97
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value \| $ / shares	13.44
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value \| $ / shares	19.42
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value \| $ / shares	16.93
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value \| $ / shares	$ 15.67	$ 18.97
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized \| $	$ 8,000,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	1 year 7 months 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value \| $	$ 5,000,000	$ 10,000,000	$ 4,000,000
Performance Shares [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
2013 RSU Award First Vesting Percent	240%
Performance Shares [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
2013 RSU Award First Vesting Percent	0%
Long-term Incentive Compensation [Domain] \| Restricted Stock Units (RSUs) [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU Award Vesting Period	3
Long-term Incentive Compensation [Domain] \| Restricted Stock Units (RSUs) [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSU Award Vesting Period	2

Employment Benefit Plans Perfor

Employment Benefit Plans Performance Units (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
PerformanceAwardsSettlementPeriod	75 days
Payment, Tax Withholding, Share-based Payment Arrangement	$ 4,000,000	$ 6,000,000	$ 3,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	504,764
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	538,163	504,764
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
PSU Payout Percentage Upon Termination	100%
2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Shareholder Return Modifier	10%
2020 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Shareholder Return Modifier	20%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Shareholder Return Modifier	2,500%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Shareholder Return Modifier	7,500%
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSUUnrecognizedCompensationYearstoGo	1 year 7 months 6 days
Target Units	100%
Payment, Tax Withholding, Share-based Payment Arrangement	$ 157,377
PerformanceStockUnitsUnrecognizedCompensationExpense	$ 8,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	722,056
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	529,285
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(422,620)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(7,361)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	918,951	722,056
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 18.97
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	13.44
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	19.42
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	16.93
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 15.67	$ 18.97
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Period Increase (Decrease)	97,591
ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsIncrease(Decrease)WeightedAverageGrantDateFairValue	$ 19.17
Performance Shares [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	0%
Performance Shares [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	240%
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
PSUUnrecognizedCompensationYearstoGo	1 year 7 months 6 days
Payment, Tax Withholding, Share-based Payment Arrangement	$ 97,871
PerformanceStockUnitsUnrecognizedCompensationExpense	$ 4,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	837,070
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	352,141
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	263,505
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(2,456)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	923,250	837,070
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 17.82
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	12.48	$ 17.39	$ 17.36
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	17.13
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	15.65
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 15.94	$ 17.82

Leases Statement (Details)

Leases Statement (Details) - USD ($) $ in Millions	12 Months Ended
Leases Statement (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Lessor, Operating Lease, Term of Contract	7 years
Operating Leases, Future Minimum Payments Receivable, Remainder of Fiscal Year	$ 1
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	5
Lessee, Operating Lease, Liability, Payments, Due Year Two	5
Lessee, Operating Lease, Liability, Payments, Due Year Three	5
Lessee, Operating Lease, Liability, Payments, Due Year Four	4
Lessee, Operating Lease, Liability, Payments, Due Year Five	4
Lessee, Operating Lease, Liability, Payments, Due after Year Five	9
Lessee, Operating Lease, Liability, Payments, Due	32
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(7)
Operating Lease, Right-of-Use Asset	21	$ 23
Operating Lease, Payments	5	5
Operating Lease, Expense	4	5
Short-Term Lease, Cost	0	0
Variable Lease, Cost	0	0
Sublease Income	(1)	(1)
Lease, Cost	4	4
Operating Lease, Liability	$ 25	$ 28
Operating Lease, Weighted Average Remaining Lease Term	6 years 9 months 18 days	7 years 8 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent	7.80%	7.70%
Operating Leases, Future Minimum Payments Receivable, in Two Years	$ 1
Operating Leases, Future Minimum Payments Receivable, in Three Years	1
Operating Leases, Future Minimum Payments Receivable, in Four Years	1
Operating Leases, Future Minimum Payments Receivable, in Five Years	1
Operating Leases, Future Minimum Payments, Due Thereafter	3
Lessor, Operating Lease, Payments to be Received	9
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 0	$ 0
Minimum [Member]
Lessee Operating Lease Remaining Lease Term	1 year
Maximum [Member]
Lessee Operating Lease Remaining Lease Term	7 years

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)
Loss Contingencies [Line Items]
Operating Leases, Future Minimum Payments, Due Thereafter	$ 3
Retiree Committee Asserted Pension Liabilities	58,500
AAC Asserted Pension Liability Overstatement	$ 9,000

Schedule I - Summary Of Investm

Schedule I - Summary Of Investments (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost	$ 2,630
Investments	2,593
Available-for-sale Securities, Amortized Cost Basis	2,041	$ 2,140
Other Investments	568	690
Available-for-sale Securities	1,966
Investments	2,593	2,955
Short-term Investments [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	507	415
Available-for-sale Securities	507	414
ShortTermInvestmentsMember, including Pledged
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	572
Available-for-sale Securities	572
Other Investments [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	528
Available-for-sale Securities	556
Other Investments [Member] \| Fixed Income Funds
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities	568
Available-for-sale Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	60
Available-for-sale Securities	59
Fixed Income Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1,469	1,605
Available-for-sale Securities	1,395	1,730
Fixed Income Securities [Member] \| Municipal Bonds [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	44	315
Available-for-sale Securities	43	340
Fixed Income Securities [Member] \| Corporate Debt Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	659	612
Available-for-sale Securities	598	613
Fixed Income Securities [Member] \| Debt Security, Government, Non-US [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	85	89
Available-for-sale Securities	76	87
Fixed Income Securities [Member] \| Residential Mortgage-Backed Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	230	182
Available-for-sale Securities	238	252
Fixed Income Securities [Member] \| Collateralized Debt Obligations [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	141	128
Available-for-sale Securities	137	128
Fixed Income Securities [Member] \| Asset-backed Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	227	234
Available-for-sale Securities	224	265
Fixed Income Securities [Member] \| U S Government Obligations [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	68
Available-for-sale Securities	65
Fixed Income Securities [Member] \| US Government Debt Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	68	45
Available-for-sale Securities	65	$ 45
Fixed Income Securities [Member] \| Corporate Obligations, Excluding Related Party Investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	659
Available-for-sale Securities	598
Fixed Income Securities [Member] \| Commercial Mortgage Backed Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Available-for-sale Securities, Amortized Cost Basis	15
Available-for-sale Securities	15
Fair Value Amount, Excluding Related Party Investments [Domain]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Investments	$ 2,581

Schedule II - Condensed Financi

Schedule II - Condensed Financial Information of Registrant (Parent Company Only) - Condensed Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock, shares issued	46,658,990	46,477,068
Treasury stock, shares	1,685,233	172,929
Common Stock, Shares, Outstanding	44,973,757
Assets:
Debt Securities, Available-for-sale	$ 1,966
Short-term investments, at cost (approximates fair value)	2,041
Other Investments	568	$ 690
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Investments, Total	2,593	2,955
Other assets	84	68
Total assets	7,973	12,303
Liabilities:
Total liabilities	6,647	11,187
Stockholders' equity (deficit):
Preferred Stock, Value, Issued	0	0
Common stock	0	0
Additional paid-in capital	274	257
Accumulated other comprehensive income (loss)	(253)	58	$ 79
Retained earnings	1,245	726
Common stock held in treasury at cost	(15)	(3)
Total Ambac Financial Group, Inc. stockholders’ equity	1,252	1,038
Total liabilities, redeemable noncontrolling interest and stockholders’ equity	7,973	12,303
Short-term investments, amortized cost	507	415
Ambac Financial Group, Inc Parent Company Only [Member]
Assets:
Short-term investments, at cost (approximates fair value)	13	130
Other Investments	16	11
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	3
Investments, Total	203	254
Cash	3	1
Investment in subsidiaries	1,029	769
Investment income due and accrued	1	1
Other assets	19	17
Total assets	1,255	1,041
Taxes Payable, Current	1	1
Liabilities:
Accounts payable and other liabilities	3	2
Total liabilities	3	3
Stockholders' equity (deficit):
Preferred Stock, Value, Issued	0	0
Common stock	0	0
Additional paid-in capital	274	257
Accumulated other comprehensive income (loss)	(253)	58
Retained earnings	1,245	726
Common stock held in treasury at cost	(15)	(3)
Total Ambac Financial Group, Inc. stockholders’ equity	1,252	1,038	$ 1,080	$ 1,477
Total liabilities, redeemable noncontrolling interest and stockholders’ equity	1,255	1,041
Short-term investments, amortized cost	175	124
Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	507	414
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Short-term Investments [Member] \| Ambac Financial Group, Inc Parent Company Only [Member]
Assets:
Short-term investments, at cost (approximates fair value)	175	124
Fixed Income Securities [Member]
Assets:
Debt Securities, Available-for-sale	1,395	1,730
Short-term investments, at cost (approximates fair value)	1,469	1,605
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Investment income due and accrued	10	10
Fixed Income Securities [Member] \| Ambac Financial Group, Inc Parent Company Only [Member]
Assets:
Debt Securities, Available-for-sale	$ 12	$ 119

Schedule II - Condensed Finan_2

Schedule II - Condensed Financial Information of Registrant (Parent Company Only) - Condensed Statement of Total Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenues:
Other income	$ 10	$ 1	$ 3
Net investment gains (losses), including impairments	(31)	(7)	(22)
Total revenues and other income	505	282	156
General and Administrative Expense	141	111	92
Expenses:
Operating Expenses	139	110
Pretax income (loss)	525	2	(440)
Income tax expense (benefit)	(2)	(18)	3
Net income (loss) attributable to common stockholders	522	(17)	(437)
Other comprehensive income, after tax:
Net income	522	(16)	(437)
Unrealized gains (losses) on securities, net of deferred income taxes of $0	(225)	(12)	15
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(85)	(8)	23
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, after Tax	0	(1)	1
Total other comprehensive income (loss), net of income tax	(310)	(21)	37
Total comprehensive income (loss) attributable to common stockholders	212	(38)	(400)
Derivative, Gain (Loss) on Derivative, Net	129	22	(50)
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax	(6)	(2)	1
Other Comprehensive Income (Loss), Foreign Currency Translation Gain (Loss) Arising During Period, Tax	0	0	0
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, Tax	0	0	0
Revenues:
Investment income	10	10	13
Other income	0
Net investment gains (losses), including impairments	14	5	1
Total revenues and other income	(2)	5	12
General and Administrative Expense	17	19	19
Expenses:
Operating Expenses	17	19	19
Pretax income (loss)	(20)	(14)	(7)
Income tax expense (benefit)	0	(2)	0
Income (loss) before equity pick-up of net income (loss) of subsidiaries	19	16	7
Equity in undistributed net income (loss) of subsidiaries	542	(1)	(430)
Net income (loss) attributable to common stockholders	522	(17)	(437)
Other comprehensive income, after tax:
Net income	522	(17)	(437)
Unrealized gains (losses) on securities, net of deferred income taxes of $0	(225)	(12)	15
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(85)	(8)	23
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Reclassification Adjustment from AOCI for Derecognition, after Tax	0	(1)	1
Changes to postretirement benefit, net of tax	(1)	(1)	(3)
Total other comprehensive income (loss), net of income tax	(310)	(21)	37
Total comprehensive income (loss) attributable to common stockholders	212	(38)	(400)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Plan Amendments, Tax Effect	0	$ 0	$ 0
Derivative, Gain (Loss) on Derivative, Net	$ 1

Schedule II - Condensed Finan_3

Schedule II - Condensed Financial Information of Registrant (Parent Company Only) - Condensed Statements of Stockholders' Equity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss), net of income tax	$ 212	$ (38)	$ (400)
Stock-based compensation	(17)	(14)	(11)
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(4)	(6)	(3)
Ending balance	1,305	1,098	1,140
Stockholders' Equity Attributable to Parent	1,252	1,038
Noncontrolling Interest, Change in Redemption Value	3	(12)
Treasury Stock, Value, Acquired, Cost Method	(14)
AMPS Impact on Stockholders Equity	(8)
Accounting Standards Update 2016-13 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Effect of New Accounting Principle			(4)
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss), net of income tax	521	(17)	(437)
Stock-based compensation	0	0	0
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(5)	(4)	(2)
Ending balance	1,245	726	759
Noncontrolling Interest, Change in Redemption Value	3	(12)
AMPS Impact on Stockholders Equity	1
Retained Earnings [Member] \| Accounting Standards Update 2016-13 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Effect of New Accounting Principle			(4)
AOCI Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss), net of income tax	(310)	(21)	37
Stock-based compensation	0	0	0
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	0	0	0
Ending balance	(253)	58	79
Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	0	0	0
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	0	0	0
Ending balance	0	0	0
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	0	0	0
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	0	0	0
Ending balance	0	0	0
Additional Paid-in Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	(17)	(14)	(11)
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	0	0	0
Ending balance	274	257	242
Common Stock Held in Treasury, at Cost [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	0	0	0
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	2	(2)	(1)
Ending balance	(15)	(3)	(1)
Treasury Stock, Value, Acquired, Cost Method	(14)
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	0	0	0
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	0	0	0
Ending balance	53	60	60
AMPS Impact on Stockholders Equity	(9)
Parent Company [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss), net of income tax	211	(38)	(400)
Stock-based compensation	(17)	(14)	(11)
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(4)	(6)	(3)
Stockholders' Equity Attributable to Parent	1,252	1,038	1,080	$ 1,477
Noncontrolling Interest, Change in Redemption Value	3	(12)
AMPS Impact on Stockholders Equity	1
Parent Company [Member] \| Accounting Standards Update 2016-13 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Effect of New Accounting Principle			(4)
Parent Company [Member] \| Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss), net of income tax	521	(17)	(437)
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	(5)	(4)	(2)
Stockholders' Equity Attributable to Parent	1,245	726	759	1,203
Noncontrolling Interest, Change in Redemption Value	3	(12)
AMPS Impact on Stockholders Equity	1
Parent Company [Member] \| Retained Earnings [Member] \| Accounting Standards Update 2016-13 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Effect of New Accounting Principle			(4)
Parent Company [Member] \| AOCI Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss), net of income tax	(310)	(21)	37
Stockholders' Equity Attributable to Parent	(253)	58	79	42
Parent Company [Member] \| Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent	0	0	0	0
Parent Company [Member] \| Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity Attributable to Parent	0	0	0	0
Parent Company [Member] \| Additional Paid-in Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	(17)	(14)	(11)
Stockholders' Equity Attributable to Parent	274	257	242	232
Parent Company [Member] \| Common Stock Held in Treasury, at Cost [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation		0
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	2	(2)	(1)
Stockholders' Equity Attributable to Parent	$ (15)	$ (3)	$ (1)	$ 0

Schedule II - Condensed Finan_4

Schedule II - Condensed Financial Information of Registrant (Parent Company Only) - Condensed Statements of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 522	$ (16)	$ (437)
Adjustments to reconcile net income loss to net cash used in operating activities:
Accretion (Amortization) of Discounts and Premiums, Investments	(11)	(13)	(15)
Net investment gains (losses), including impairments	(31)	(7)	(22)
Share-based compensation	17	14	11
Proceeds from Contributions from Affiliates	6	6
Other, net	(152)	(33)	67
Net cash provided by (used in) operating activities	1,335	(131)	(175)
Cash flows from investing activities:
Proceeds from matured bonds	206	698	137
Purchases of bonds	(403)	(343)	(975)
Change in short-term investments	(52)	98	158
Proceeds from Sale and Maturity of Other Investments	166	39	374
Payments for (Proceeds from) Other Investing Activities	9	(5)	1
Net cash provided by investing activities	866	776	432
Cash flows from financing activities:
Net Cash Provided by (Used in) Financing Activities	(2,163)	(657)	(303)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	38	(12)	(46)
Cash and cash equivalents at beginning of period	17	20
Cash and cash equivalents end of period	31	17	20
Cash paid during the period for:
Income taxes	6	15	11
Payments to Acquire Businesses, Net of Cash Acquired	(18)	0	(74)
Payments for Repurchase of Common Stock	(14.2)
Ambac Financial Group, Inc Parent Company Only [Member]
Cash flows from operating activities:
Net income	522	(17)	(437)
Adjustments to reconcile net income loss to net cash used in operating activities:
Equity in undistributed net (income) loss of non-debtor subsidiaries	(542)	1	423
Accretion (Amortization) of Discounts and Premiums, Investments	(7)	(9)	(6)
Net investment gains (losses), including impairments	14	5	1
Decrease in current income taxes payable	(1)	1	30
Share-based compensation	12	14	11
Decrease in other assets	41	(5)	(1)
Other, net	1	(6)	(10)
Net cash provided by (used in) operating activities	46	(10)	11
Cash flows from investing activities:
Proceeds from matured bonds	68	33	46
Purchases of bonds	(1)	(34)	(45)
Change in short-term investments	(51)	105	89
Proceeds from Sale and Maturity of Other Investments	(4)	(8)	0
Net cash provided by investing activities	12	95	16
Capital Contribution to Subsidiaries	(42)	(92)	(29)
Cash flows from financing activities:
Net Cash Provided by (Used in) Financing Activities	(57)	(92)	(29)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	1	(6)	(2)
Cash and cash equivalents at beginning of period	1	7	9
Cash and cash equivalents end of period	3	1	7
Cash paid during the period for:
Income taxes	0	$ 0	$ 0
Payments for Repurchase of Common Stock	(14)
Parent [Member]
Adjustments to reconcile net income loss to net cash used in operating activities:
Net investment gains (losses), including impairments	$ (4)

Schedule II - Condensed Finan_5

Schedule II - Condensed Financial Information of Registrant (Parent Company Only) Schedule II - Condensed Financial Information of Registrant - Additional Information (Details)	Apr. 29, 1991
Entity Incorporation, Date of Incorporation	Apr. 29, 1991

Schedule II - Condensed Finan_6

Schedule II - Condensed Financial Information of Registrant (Parent Company Only) Schedule II - Condensed Financial Information of Registrant - Income Taxes (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)
Operating Loss Carryforwards	$ 3,454
Minimum [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2030
Maximum [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2043
AFG [Member]
Operating Loss Carryforwards	$ 1,630
Ambac Assurance [Member]
Operating Loss Carryforwards	1,824
Interest Expense \| U. S. Federal Net Operating Tax [Member]
Operating Loss Carryforwards	$ 314

SEC Schedule, Article 12-16, Su

SEC Schedule, Article 12-16, Supplementary Insurance Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Liability for Claims and Claims Adjustment Expense	$ 805	$ 1,570
Unearned premiums	372	395
Premiums Earned, Net	56	47	$ 54
Net Investment Income	17	139	122
Policyholder Benefits and Claims Incurred, Net	(396)
Deferred Policy Acquisition Costs, Amortization Expense	3	1	0
General and Administrative Expense	141	111	92
Premiums Written, Net	23	(33)	$ 0
Financial Guarantee
Liability for Claims and Claims Adjustment Expense	715	1,538
Deferred Policy Acquisition Cost	0	0
Unearned premiums	287	385
Premiums Earned, Net	42	46
Net Investment Income	12	138
Policyholder Benefits and Claims Incurred, Net	(406)	(89)
Deferred Policy Acquisition Costs, Amortization Expense	0
General and Administrative Expense	104	78
Premiums Written, Net	(6)	(35)
Property and Casualty, Commercial Insurance
Liability for Claims and Claims Adjustment Expense	90	32
Deferred Policy Acquisition Cost	3	0
Unearned premiums	85	10
Premiums Earned, Net	14	1
Net Investment Income	2	1
Policyholder Benefits and Claims Incurred, Net	9	0
Deferred Policy Acquisition Costs, Amortization Expense	3	0
General and Administrative Expense	13	9
Premiums Written, Net	29	3
Corporate and Other
Net Investment Income	$ 3	$ 1