Basis of Presentation and Significant Accounting Policies (Notes)	3 Months Ended
Mar. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES The Company has disclosed its significant accounting policies in Note 2. Significant Accounting Policies in the Notes to Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014. The following significant accounting policies provide an update to those included in the Company’s Annual Report on Form 10-K. Basis of Presentation The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial reporting and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by GAAP for annual periods. These statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Annual Report on Form 10-K for the year ended December 31, 2014. The accompanying consolidated financial statements have not been audited by an independent registered public accounting firm in accordance with the standards of the Public Company Accounting Oversight Board (U.S.), but in the opinion of management such financial statements include all adjustments, consisting only of normal recurring adjustments, necessary for the fair statement of the Company’s consolidated financial position and results of operations. All material intercompany balances and transactions have been eliminated. The results of operations for the three months ended March 31, 2015 may not be indicative of the results that may be expected for the year ending December 31, 2015. The December 31, 2014 consolidated balance sheet was derived from audited financial statements. The preparation of financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. As additional information becomes available or actual amounts become determinable, the recorded estimates are revised and reflected in operating results. Reclassifications Certain reclassifications have been made to prior years' amounts to conform to the current year's presentation. Recently Adopted and Recently Issued Accounting Standards Adopted: Effective January 1, 2015, Ambac adopted ASU 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360) - Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity. The objective of this ASU is to limit discontinued operations reporting to disposals of components of an entity that represent strategic shifts that have (or will have) a major effect on an entity's operations and financial results. Under previous U.S. GAAP, many disposals, some of which may be routine in nature and not a change in an entity's strategy, were reported in discontinued operations. The ASU also requires certain expanded disclosures for discontinued operations and disclosure of the pre-tax profit or loss of an individually significant component of an entity that does not qualify for discontinued operations reporting. The adoption of this ASU did not have a material effect on Ambac's financial statements. Issued: In April 2015, the FASB issued ASU 2015-03, Interest - Imputation of Interest (Subtopic 835-30). This ASU simplifies the presentation of debt issuance costs by requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this ASU. The ASU is effective for annual periods and interim periods within those annual periods beginning after December 15, 2015. Early adoption is also permitted for financial statements that have not been previously issued. Upon adoption, the ASU must be retrospectively applied to all prior periods presented. Ambac will adopt ASU 2015-02 on January 1, 2016. The adoption of this ASU is not expected to have a material impact on Ambac's financial statements. In May 2015, the FASB issued ASU 2015-07, Fair Value Measurement (Topic 820) - Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent). Reporting entities are permitted to use net asset value ("NAV") as a practical expedient to measure the fair value of certain investments. Under current U.S. GAAP, investments that use the NAV practical expedient to measure fair value are categorized within the fair value hierarchy as level 2 or level 3 investments depending on their redemption attributes, which has led to diversity in practice. This ASU will remove the requirement to categorize within the fair value hierarchy all investments that use the NAV practical expedient for fair value measurement purposes. Furthermore, the ASU will remove the requirement to make certain disclosures for all investments that are eligible to be measured at fair value using the NAV practical expedient. The ASU is effective for fiscal years beginning after December 15, 2015 and interim periods with those fiscal years. The ASU must be applied retrospectively to all prior periods presented. Ambac will adopt ASU 2015-07 on January 1, 2016. The adoption of this ASU is not expected to have a material impact on Ambac's financial statements. Basis of Presentation The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial reporting and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by GAAP for annual periods. These statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Annual Report on Form 10-K for the year ended December 31, 2014. The accompanying consolidated financial statements have not been audited by an independent registered public accounting firm in accordance with the standards of the Public Company Accounting Oversight Board (U.S.), but in the opinion of management such financial statements include all adjustments, consisting only of normal recurring adjustments, necessary for the fair statement of the Company’s consolidated financial position and results of operations. All material intercompany balances and transactions have been eliminated. The results of operations for the three months ended March 31, 2015 may not be indicative of the results that may be expected for the year ending December 31, 2015. The December 31, 2014 consolidated balance sheet was derived from audited financial statements. The preparation of financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. As additional information becomes available or actual amounts become determinable, the recorded estimates are revised and reflected in operating results.

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES

The Company has disclosed its significant accounting policies in Note 2. Significant Accounting Policies in the Notes to Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014. The following significant accounting policies provide an update to those included in the Company’s Annual Report on Form 10-K.

Basis of Presentation

The accompanying unaudited consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("GAAP") for interim financial reporting and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by GAAP for annual periods. These statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Annual Report on Form 10-K for the year ended December 31, 2014. The accompanying consolidated financial statements have not been audited by an independent registered public accounting firm in accordance with the standards of the Public Company Accounting Oversight Board (U.S.), but in the opinion of management such financial statements include all adjustments, consisting only of normal recurring adjustments, necessary for the fair statement of the Company’s consolidated financial position and results of operations. All material intercompany balances and transactions have been eliminated. The results of operations for the three months ended March 31, 2015 may not be indicative of the results that may be expected for the year ending December 31, 2015. The December 31, 2014 consolidated balance sheet was derived from audited financial statements.

The preparation of financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. As additional information becomes available or actual amounts become determinable, the recorded estimates are revised and reflected in operating results.

Reclassifications

Certain reclassifications have been made to prior years' amounts to conform to the current year's presentation.

Recently Adopted and Recently Issued Accounting Standards

Adopted:

Effective January 1, 2015, Ambac adopted ASU 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360) - Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity. The objective of this ASU is to limit discontinued operations reporting to disposals of components of an entity that represent strategic shifts that have (or will have) a major effect on an entity's operations and financial results. Under previous U.S. GAAP, many disposals, some of which may be routine in nature and not a change in an entity's strategy, were reported in discontinued operations. The ASU also requires certain expanded disclosures for discontinued operations and disclosure of the pre-tax profit or loss of an individually significant component of an entity that does not qualify for discontinued operations reporting. The adoption of this ASU did not have a material effect on Ambac's financial statements.

Issued:

In April 2015, the FASB issued ASU 2015-03, Interest - Imputation of Interest (Subtopic 835-30). This ASU simplifies the presentation of debt issuance costs by requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this ASU. The ASU is effective for annual periods and interim periods within those annual periods beginning after December 15, 2015. Early adoption is also permitted for financial statements that have not been previously issued. Upon adoption, the ASU must be retrospectively applied to all prior periods presented. Ambac will adopt ASU 2015-02 on January 1, 2016. The adoption of this ASU is not expected to have a material impact on Ambac's financial statements.

In May 2015, the FASB issued ASU 2015-07, Fair Value Measurement (Topic 820) - Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent). Reporting entities are permitted to use net asset value ("NAV") as a practical expedient to measure the fair value of certain investments. Under current U.S. GAAP, investments that use the NAV practical expedient to measure fair value are categorized within the fair value hierarchy as level 2 or level 3 investments depending on their redemption attributes, which has led to diversity in practice. This ASU will remove the requirement to categorize within the fair value hierarchy all investments that use the NAV practical expedient for fair value measurement purposes. Furthermore, the ASU will remove the requirement to make certain disclosures for all investments that are eligible to be measured at fair value using the NAV practical expedient. The ASU is effective for fiscal years beginning after December 15, 2015 and interim periods with those fiscal years. The ASU must be applied retrospectively to all prior periods presented. Ambac will adopt ASU 2015-07 on January 1, 2016. The adoption of this ASU is not expected to have a material impact on Ambac's financial statements.

Basis of Presentation