Background and Business Description	9 Months Ended
Sep. 30, 2013
Accounting Policies [Abstract]
Background and Business Description	1. BACKGROUND AND BUSINESS DESCRIPTION These unaudited consolidated financial statements and notes thereto should be read in conjunction with the consolidated financial statements and notes thereto included in Ambac’s 2012 Annual Report on Form 10-K. Certain reclassifications may have been made to prior periods’ amounts to conform to the current period’s presentation. *Ambac Financial Group, Inc.* Ambac Financial Group, Inc. (“Ambac” or the “Company”), headquartered in New York City, is a financial services holding company incorporated in the state of Delaware. On May 1, 2013 (the “Effective Date”), the Second Modified Fifth Amended Plan of Reorganization of Ambac Financial Group, Inc. (the “Reorganization Plan”) became effective and Ambac emerged from bankruptcy. Pursuant to the Reorganization Plan, Ambac issued common stock and warrants that were listed on NASDAQ and began trading under the symbols “AMBC” and “AMBCW,” respectively, on May 1, 2013. Also as provided for in the Reorganization Plan, Ambac’s Amended and Restated Certificate of Incorporation and revised Bylaws became effective on the Effective Date. Ambac’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 Ambac’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 Ambac’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 Wisconsin Office of the Commissioner of Insurance (“OCI”), which is the primary regulator of Ambac Assurance Corporation (“Ambac Assurance”), the principal operating subsidiary of the Company. There are substantial restrictions on the ability to transfer Ambac’s common stock set forth in Article XII of Ambac’s Amended and Restated Certificate of Incorporation. 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 the Company’s common stock or (ii) the percentage stock ownership interest in Ambac of any holder of 5% or more of the Company’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 Ambac’s Board of Directors to such transfer. A purported transferee of a Prohibited Transfer shall not be recognized as a stockholder of Ambac 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 Ambac, 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 Ambac, 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 Ambac with respect to such Excess Securities, to an agent designated by Ambac. 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 Ambac’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. Upon emergence from bankruptcy the Company adopted fresh start financial statement reporting, as described more fully in Note 2. The adoption of fresh start accounting principles reflects the Company’s becoming a new entity for financial reporting purposes. *Segregated Account of Ambac Assurance Corporation* In March 2010, Ambac Assurance established a Segregated Account pursuant to Wisc. Stat. §611.24(2) (the “Segregated Account”) to segregate certain segments of Ambac Assurance’s liabilities, and OCI commenced rehabilitation proceedings in the Dane County, Wisconsin Circuit Court (the “Rehabilitation Court”) with respect to the Segregated Account (the “Segregated Account Rehabilitation Proceedings”) in order to permit OCI to facilitate an orderly run-off and/or settlement of the liabilities allocated to the Segregated Account pursuant to the provisions of the Wisconsin Insurers Rehabilitation and Liquidation Act. Net par exposure as of September 30, 2013 for policies allocated to the Segregated Account is $23,729,552. In 2010, Ambac Assurance issued a $2,000,000 secured note due in 2050 (the “Secured Note”) to the Segregated Account. Interest on the Secured Note accrues at the rate of 4.5% per annum, and accrued interest will be added to principal quarterly. The Segregated Account has the ability to demand payment under the Secured Note from time to time to pay claims and other liabilities. The balance of the Secured Note is $195,831 at September 30, 2013, including capitalized interest since the date of issuance. The Segregated Account also has the ability to demand payment from time to time under an aggregate excess of loss reinsurance agreement provided by Ambac Assurance (the “Reinsurance Agreement”) to pay claims and other liabilities after the Secured Note is fully drawn. Ambac Assurance is not obligated to make payments on the Secured Note or under the Reinsurance Agreement if its surplus as regards to policyholders is less than $100,000 (the “Minimum Surplus Amount”). As long as the surplus as regards to policyholders is not less than the Minimum Surplus Amount, payments by Ambac Assurance to the Segregated Account under the Secured Note and the Reinsurance Agreement are not capped. At September 30, 2013, insurance liabilities for policies allocated to the Segregated Account were $6,130,867. At September 30, 2013, Ambac Assurance’s surplus as regards to policyholders of $501,672 exceeds the Minimum Surplus Amount. On October 8, 2010, the Commissioner of Insurance for the State of Wisconsin, in his capacity as the court-appointed rehabilitator of the Segregated Account (the “Rehabilitator”) filed a plan of rehabilitation for the Segregated Account (the “Segregated Account Rehabilitation Plan”) in the Rehabilitation Court. The Rehabilitation Court confirmed the Segregated Account Rehabilitation Plan on January 24, 2011. The confirmed Segregated Account Rehabilitation Plan also made permanent the injunctions issued by the Rehabilitation Court on March 24, 2010. The Segregated Account Rehabilitation Plan has not been made effective and is subject to modification. On June 4, 2012, the Rehabilitation Court approved a motion made by the Rehabilitator to make partial interim policy claim payments to Segregated Account policyholders. In accordance with such approval, on August 1, 2012, the Rehabilitator promulgated Rules Governing the Submission, Processing and Partial Payment of Policy Claims in accordance with the June 4, 2012 Interim Cash Payment Order (the “Policy Claim Rules”). Pursuant to the Policy Claim Rules, effective from August 1, 2012, holders of policies allocated to the Segregated Account were, and continue to be, allowed to submit policy claims for review and partial payment equating to 25% of the permitted policy claim amount. On July 11, 2013 the Rehabilitator filed a motion with the Rehabilitation Court seeking approval from the Rehabilitation Court for the Segregated Account to make cash payments in excess of 25% of the permitted policy claim amount (“Supplemental Payments”) with respect to 14 policies (the “Identified Policies”) so that cash flow in the related securitization trusts that would have been available to reimburse Ambac Assurance had it paid claims in full under such policies is not diverted to uninsured holders who would not have received such cash flow if claims had been paid in full. The motion also sought authorization for the payment of Supplemental Payments on other policies identified from time to time where similar reimbursements are available (together with the Identified Policies, the “SP Policies”). Without making such Supplemental Payments, Ambac Assurance would likely realize lower levels of reimbursements and subrogation recoverables as cash flow that would have been available for the benefit of Ambac Assurance in relation to the SP Policies would be lost to such uninsured holders. A hearing on such motion was held on August 2, 2013, following which the Rehabilitation Court granted such motion and entered an order permitting Supplemental Payments to be made with respect to the SP Policies. As a result, the Segregated Account began making Supplemental Payments on certain SP Policies in August 2013. In September 2013, the Rehabilitator submitted a request for rulings from the United States Internal Revenue Service (“IRS”) as to certain tax issues associated with potential amendments to the Segregated Account Rehabilitation Plan. Pursuant to such amendments, surplus notes would not be issued with respect to the unpaid balance of permitted policy claims, but such balance would be recorded by the Segregated Account as outstanding policy obligations which would accrue interest at a rate of 5.1%, from the date on which the initial portion (currently 25%) of any such permitted policy claim is paid, compounded annually until paid (any such outstanding policy obligation, including accrued interest thereon, as such obligation may be adjusted from time to time in accordance with the Segregated Account Rehabilitation Plan, guidelines or rules issued by the Rehabilitator and/or orders of the Rehabilitation Court, a “Deferred Amount”). If favorable rulings are received by the Rehabilitator from the IRS as to such tax issues, then the Rehabilitator would likely file amendments to the Segregated Account Rehabilitation Plan to provide for Deferred Amounts to be established, rather than for surplus notes to be issued, with respect to the unpaid portion of permitted policy claims. The timing and likelihood of such amendments to the Segregated Account Rehabilitation Plan are presently unclear, but such amendments could result in a material change to our financial results. As more fully described in Note 12, on October 24, 2013, the Wisconsin Court of Appeals affirmed orders of the Rehabilitation Court entered in connection with the Segregated Account Rehabilitation Proceedings, thus upholding the Segregated Account Rehabilitation Plan and actions taken by the Rehabilitator or Wisconsin Commissioner of Insurance in formulating such Plan.

1. BACKGROUND AND BUSINESS DESCRIPTION

These unaudited consolidated financial statements and notes thereto should be read in conjunction with the consolidated financial statements and notes thereto included in Ambac’s 2012 Annual Report on Form 10-K. Certain reclassifications may have been made to prior periods’ amounts to conform to the current period’s presentation.

Ambac Financial Group, Inc.

Ambac Financial Group, Inc. (“Ambac” or the “Company”), headquartered in New York City, is a financial services holding company incorporated in the state of Delaware. On May 1, 2013 (the “Effective Date”), the Second Modified Fifth Amended Plan of Reorganization of Ambac Financial Group, Inc. (the “Reorganization Plan”) became effective and Ambac emerged from bankruptcy.

Pursuant to the Reorganization Plan, Ambac issued common stock and warrants that were listed on NASDAQ and began trading under the symbols “AMBC” and “AMBCW,” respectively, on May 1, 2013.

Also as provided for in the Reorganization Plan, Ambac’s Amended and Restated Certificate of Incorporation and revised Bylaws became effective on the Effective Date. Ambac’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 Ambac’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 Ambac’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 Wisconsin Office of the Commissioner of Insurance (“OCI”), which is the primary regulator of Ambac Assurance Corporation (“Ambac Assurance”), the principal operating subsidiary of the Company.

There are substantial restrictions on the ability to transfer Ambac’s common stock set forth in Article XII of Ambac’s Amended and Restated Certificate of Incorporation. 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 the Company’s common stock or (ii) the percentage stock ownership interest in Ambac of any holder of 5% or more of the Company’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 Ambac’s Board of Directors to such transfer. A purported transferee of a Prohibited Transfer shall not be recognized as a stockholder of Ambac 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 Ambac, 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 Ambac, 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 Ambac with respect to such Excess Securities, to an agent designated by Ambac. 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 Ambac’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.

Upon emergence from bankruptcy the Company adopted fresh start financial statement reporting, as described more fully in Note 2. The adoption of fresh start accounting principles reflects the Company’s becoming a new entity for financial reporting purposes.

Segregated Account of Ambac Assurance Corporation

In March 2010, Ambac Assurance established a Segregated Account pursuant to Wisc. Stat. §611.24(2) (the “Segregated Account”) to segregate certain segments of Ambac Assurance’s liabilities, and OCI commenced rehabilitation proceedings in the Dane County, Wisconsin Circuit Court (the “Rehabilitation Court”) with respect to the Segregated Account (the “Segregated Account Rehabilitation Proceedings”) in order to permit OCI to facilitate an orderly run-off and/or settlement of the liabilities allocated to the Segregated Account pursuant to the provisions of the Wisconsin Insurers Rehabilitation and Liquidation Act. Net par exposure as of September 30, 2013 for policies allocated to the Segregated Account is $23,729,552.

In 2010, Ambac Assurance issued a $2,000,000 secured note due in 2050 (the “Secured Note”) to the Segregated Account. Interest on the Secured Note accrues at the rate of 4.5% per annum, and accrued interest will be added to principal quarterly. The Segregated Account has the ability to demand payment under the Secured Note from time to time to pay claims and other liabilities. The balance of the Secured Note is $195,831 at September 30, 2013, including capitalized interest since the date of issuance. The Segregated Account also has the ability to demand payment from time to time under an aggregate excess of loss reinsurance agreement provided by Ambac Assurance (the “Reinsurance Agreement”) to pay claims and other liabilities after the Secured Note is fully drawn.

Ambac Assurance is not obligated to make payments on the Secured Note or under the Reinsurance Agreement if its surplus as regards to policyholders is less than $100,000 (the “Minimum Surplus Amount”). As long as the surplus as regards to policyholders is not less than the Minimum Surplus Amount, payments by Ambac Assurance to the Segregated Account under the Secured Note and the Reinsurance Agreement are not capped. At September 30, 2013, insurance liabilities for policies allocated to the Segregated Account were $6,130,867. At September 30, 2013, Ambac Assurance’s surplus as regards to policyholders of $501,672 exceeds the Minimum Surplus Amount.

On October 8, 2010, the Commissioner of Insurance for the State of Wisconsin, in his capacity as the court-appointed rehabilitator of the Segregated Account (the “Rehabilitator”) filed a plan of rehabilitation for the Segregated Account (the “Segregated Account Rehabilitation Plan”) in the Rehabilitation Court. The Rehabilitation Court confirmed the Segregated Account Rehabilitation Plan on January 24, 2011. The confirmed Segregated Account Rehabilitation Plan also made permanent the injunctions issued by the Rehabilitation Court on March 24, 2010. The Segregated Account Rehabilitation Plan has not been made effective and is subject to modification. On June 4, 2012, the Rehabilitation Court approved a motion made by the Rehabilitator to make partial interim policy claim payments to Segregated Account policyholders. In accordance with such approval, on August 1, 2012, the Rehabilitator promulgated Rules Governing the Submission, Processing and Partial Payment of Policy Claims in accordance with the June 4, 2012 Interim Cash Payment Order (the “Policy Claim Rules”). Pursuant to the Policy Claim Rules, effective from August 1, 2012, holders of policies allocated to the Segregated Account were, and continue to be, allowed to submit policy claims for review and partial payment equating to 25% of the permitted policy claim amount.

On July 11, 2013 the Rehabilitator filed a motion with the Rehabilitation Court seeking approval from the Rehabilitation Court for the Segregated Account to make cash payments in excess of 25% of the permitted policy claim amount (“Supplemental Payments”) with respect to 14 policies (the “Identified Policies”) so that cash flow in the related securitization trusts that would have been available to reimburse Ambac Assurance had it paid claims in full under such policies is not diverted to uninsured holders who would not have received such cash flow if claims had been paid in full. The motion also sought authorization for the payment of Supplemental Payments on other policies identified from time to time where similar reimbursements are available (together with the Identified Policies, the “SP Policies”). Without making such Supplemental Payments, Ambac Assurance would likely realize lower levels of reimbursements and subrogation recoverables as cash flow that would have been available for the benefit of Ambac Assurance in relation to the SP Policies would be lost to such uninsured holders. A hearing on such motion was held on August 2, 2013, following which the Rehabilitation Court granted such motion and entered an order permitting Supplemental Payments to be made with respect to the SP Policies. As a result, the Segregated Account began making Supplemental Payments on certain SP Policies in August 2013.

In September 2013, the Rehabilitator submitted a request for rulings from the United States Internal Revenue Service (“IRS”) as to certain tax issues associated with potential amendments to the Segregated Account Rehabilitation Plan. Pursuant to such amendments, surplus notes would not be issued with respect to the unpaid balance of permitted policy claims, but such balance would be recorded by the Segregated Account as outstanding policy obligations which would accrue interest at a rate of 5.1%, from the date on which the initial portion (currently 25%) of any such permitted policy claim is paid, compounded annually until paid (any such outstanding policy obligation, including accrued interest thereon, as such obligation may be adjusted from time to time in accordance with the Segregated Account Rehabilitation Plan, guidelines or rules issued by the Rehabilitator and/or orders of the Rehabilitation Court, a “Deferred Amount”). If favorable rulings are received by the Rehabilitator from the IRS as to such tax issues, then the Rehabilitator would likely file amendments to the Segregated Account Rehabilitation Plan to provide for Deferred Amounts to be established, rather than for surplus notes to be issued, with respect to the unpaid portion of permitted policy claims. The timing and likelihood of such amendments to the Segregated Account Rehabilitation Plan are presently unclear, but such amendments could result in a material change to our financial results.

As more fully described in Note 12, on October 24, 2013, the Wisconsin Court of Appeals affirmed orders of the Rehabilitation Court entered in connection with the Segregated Account Rehabilitation Proceedings, thus upholding the Segregated Account Rehabilitation Plan and actions taken by the Rehabilitator or Wisconsin Commissioner of Insurance in formulating such Plan.