Description Of Business, Basis Of Presentation, And Changes In Significant Accounting Policies	9 Months Ended
Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block]	Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies Ally Financial Inc. (formerly GMAC Inc. and referred to herein as Ally, we, our, or us) is a leading, independent, diversified, financial services firm. Founded in 1919, we are a leading automotive financial services company with approximately 95 years of experience, providing a broad array of financial products and services to automotive dealers and their customers. We operate as a financial holding company and a bank holding company. Our banking subsidiary, Ally Bank, is an indirect wholly owned subsidiary of Ally Financial Inc. and a leading franchise in the growing direct (internet, telephone, mobile, and mail) banking market. Our accounting and reporting policies conform to accounting principles generally accepted in the United States of America (GAAP). Additionally, where applicable, the policies conform to the accounting and reporting guidelines prescribed by bank regulatory authorities. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and that affect income and expenses during the reporting period. In developing the estimates and assumptions, management uses all available evidence; however, actual results could differ. The Condensed Consolidated Financial Statements at September 30, 2014, and for the three months and nine months ended September 30, 2014, and 2013, are unaudited but reflect all adjustments that are, in management’s opinion, necessary for the fair presentation of the results for the interim periods presented. All such adjustments are of a normal recurring nature. These unaudited Condensed Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements (and the related notes) included in our Annual Report on Form 10-K for the year ended December 31, 2013, as filed on March 3, 2014, with the U.S. Securities and Exchange Commission (SEC). Initial Public Offering of Common Stock, Stock Split, and Changes in Number of Shares Authorized In April 2014, we completed an initial public offering (IPO) of our common stock. All proceeds from the offering were obtained by the U.S. Department of the Treasury (Treasury) as the single selling stockholder. In connection with the IPO, we effected a 310-for-one stock split on shares of our common stock, $0.01 par value per share. Accordingly, all references in the Condensed Consolidated Financial Statements to share and per share amounts relating to common stock have been adjusted, on a retroactive basis, to recognize the 310-for-one stock split. In addition, on April 9, 2014, we increased the number of shares authorized for issuance of common stock to 1.1 billion and decreased the number of shares authorized for issuance of Series A Preferred Stock to approximately 41 million. Significant Accounting Policies Income Taxes In calculating the provision for interim income taxes, in accordance with Accounting Standards Codification (ASC) 740, Income Taxes, we apply an estimated annual effective tax rate to year-to-date ordinary income. At the end of each interim period, we estimate the effective tax rate expected to be applicable for the full fiscal year. This method differs from that described in Note 1 to the Consolidated Financial Statements in our 2013 Annual Report on Form 10-K, which describes our annual significant income tax accounting policy and related methodology. Refer to Note 1 to the Consolidated Financial Statements in our 2013 Annual Report on Form 10-K regarding additional significant accounting policies. Recently Adopted Accounting Standards Liabilities — Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation Is Fixed at the Reporting Date (ASU 2013-04) As of January 1, 2014, we adopted Accounting Standards Update (ASU) 2013-04. The guidance within the ASU requires an entity to measure obligations resulting from joint and several liability arrangements for which the total amount of the obligation within the scope of this guidance is fixed at the reporting date, as the sum of the following: (a) The amount the reporting entity agreed to pay on the basis of its arrangement among its co-obligors and (b) any additional amount the reporting entity expects to pay on behalf of its co-obligors. The amendments were effective retrospectively for all arrangements within its scope. It further requires an entity to disclose the nature and amount of the obligation as well as other information about those obligations. The adoption of this guidance did not have a material effect on our consolidated financial condition or results of operations. Foreign Currency Matters — Parent's Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entity (ASU 2013-05) As of January 1, 2014, we adopted ASU 2013-05. The guidance within the ASU closes diversity in practice in this area and requires a reporting entity that ceases to have a controlling financial interest, in a subsidiary or group of assets or a business, within a foreign entity to release any related Cumulative Translation Adjustment (CTA) into net income. The CTA should be released into net income only if the sale or transfer results in the complete or substantially complete liquidation of the foreign entity. For an equity method investment that is a foreign entity, a pro rata portion of the CTA should be released into net income upon a partial sale of such an investment. This ASU further clarifies that the sale of an investment in a foreign entity includes both events that result in the loss of a controlling financial interest in a foreign entity, irrespective of any retained investment, and events that result in step acquisition under which an acquirer obtains control of an acquiree in which it held an equity interest immediately before the acquisition date. Under these circumstances, the CTA should be released into net income upon their occurrence. The amendments are to be applied prospectively for all transactions within its scope. Since the guidance is prospective and we have previously sold or exited substantially all of our international businesses and released the related CTA upon those dispositions, the adoption of this guidance did not have a material effect on our consolidated financial condition or results of operations. Income Taxes — Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists (ASU 2013-11) As of January 1, 2014, we adopted ASU 2013-11. The guidance within the ASU closes diversity in practice and requires an unrecognized tax benefit, or a portion of an unrecognized tax benefit, to be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward. The guidance further includes an exception that if a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available to settle any additional income taxes that would result from the disallowance of a tax position at the reporting date or the tax law of the applicable jurisdiction does not require the entity to use them and the entity does not intend to use them, the unrecognized tax benefit for such purpose should be presented in the financial statements as a liability and should not be combined with deferred tax assets. The assessment of whether a deferred tax asset is available is based on the unrecognized tax benefit and deferred tax asset that exist at the reporting date and should be made presuming disallowance of the tax position at the reporting date. The amendments are to be applied prospectively to all unrecognized tax benefits that exist at the effective date. The adoption of this guidance did not have a material effect to our consolidated financial condition or results of operations. Investments — Accounting for Investments in Qualified Affordable Housing Projects (ASU 2014-01) As of January 1, 2014, we adopted ASU 2014-01. The amendments in this ASU allow an entity to make an accounting policy election to account for investments in qualified affordable housing projects using a proportional amortization method, if certain conditions are met. Under the election, the entity would amortize the initial cost of the investment in proportion to the tax credits and other benefits received while recognizing the net investment performance in the statement of comprehensive income as a component of income tax expense. The amendments are to be applied retrospectively to all periods presented. We have elected to utilize the proportional amortization method for qualifying affordable housing investments and therefore will be presenting the amortization and tax impacts of such investments as a component of income tax expense under the proportional amortization method. The adoption of this guidance did not have a material effect to our consolidated financial condition or results of operations. Recently Issued Accounting Standards Receivables — Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure (ASU 2014-04) In January 2014, the Financial Accounting Standards Board (FASB) issued ASU 2014-04. The amendments in this ASU clarify the timing for which an entity should reclassify a loan that has been foreclosed or where an in substance repossession has occurred to real estate owned. The guidance requires such reclassification to occur when the entity obtains legal title upon completion of foreclosure or the borrower conveys all interest in the residential real estate property to the entity to satisfy the loan through completion of a deed in lieu of foreclosure or similar legal agreement. In addition, the ASU clarifies that redemption rights of the borrower should be ignored for purposes of determining whether legal title has transferred. The amendments are effective for us beginning on January 1, 2015. The amendments can be applied using either a modified retrospective or prospective basis. Under the modified retrospective approach, the entity should record a cumulative-effect adjustment to residential consumer mortgage loans and residential real estate owned as of the beginning of the annual period for which the amendments are effective. Early adoption is permitted. Management is assessing the impact of the adoption of this guidance. Presentation of Financial Statements and Property, Plant, and Equipment — Reporting Discontinued Operations and Disclosure of Disposals of Components of an Entity (ASU 2014-08) In April 2014, the FASB issued ASU 2014-08. The amendments in this ASU modify the requirements for the reporting of discontinued operations. In order to qualify as a discontinued operation, the disposal of a component of an entity, a group of components, or a business of an entity must represent a strategic shift that has (or will have) a major effect on an entity’s operations and financial results. The ASU further indicates that the timing for recording a discontinued operation is when one of the following occurs: the component, group of components, or business meets the criteria to be classified as held for sale; the component, group of components, or business is disposed of by sale; or the component, group of components, or business is disposed of other than by sale (for example abandonment or spinoff). In addition, the ASU also requires additional disclosure items about an entity’s discontinued operations. The amendments are effective for us beginning on January 1, 2015. The amendments are to be applied prospectively solely to newly identified disposals that qualify as discontinued operations after the effective date. Items previously reported as discontinued operations will maintain their classification based on the prior guidance. Early adoption is permitted, but only for disposals that have not been previously reported as discontinued operations in previously issued financial statements. Because the guidance is prospective only for newly identified disposals that qualify as a discontinued operation, this guidance is not expected to have a material impact to our consolidated financial condition or results of operations upon adoption. Revenue from Contracts with Customers (ASU 2014-09) In May 2014, the FASB issued ASU 2014-09. The purpose of this guidance is to streamline and consolidate existing revenue recognition principles in GAAP and to converge revenue recognition principles with International Financial Reporting Standards (IFRS). The core principle of the amendments is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to receive in exchange for those goods or services. The amendments include a five step process for consideration of the main principle, guidance on accounting treatment for costs associated with a contract, and disclosure requirements related to the revenue process. The amendments are effective for us beginning on January 1, 2017. The amendments can be applied either through a full retrospective application or retrospectively with a cumulative effect adjustment on the date of initial adoption. Early adoption is prohibited. Management is assessing the impact of the adoption of this guidance. Transfers and Servicing — Repurchase-to-Maturity Transactions, Repurchase Financings and Disclosures (ASU 2014-11) In June 2014, the FASB issued ASU 2014-11. The amendments in this ASU change the accounting for repurchase to maturity transactions and repurchase financing transactions such that both will be reported as secured borrowings when the guidance becomes effective. In addition to the changes to how these transactions are reported, the ASU also includes new disclosure requirements. The amendments are effective for us beginning on January 1, 2015. The amendments are to be applied to all transactions that fall under the guidance as of the date of adoption with a cumulative effect adjustment recorded on the date of initial adoption. Early adoption is prohibited. The guidance is not expected to have a material impact to our consolidated financial condition or results of operations.

Description of Business, Basis of Presentation, and Changes in Significant Accounting Policies

Ally Financial Inc. (formerly GMAC Inc. and referred to herein as Ally, we, our, or us) is a leading, independent, diversified, financial services firm. Founded in 1919, we are a leading automotive financial services company with approximately 95 years of experience, providing a broad array of financial products and services to automotive dealers and their customers. We operate as a financial holding company and a bank holding company. Our banking subsidiary, Ally Bank, is an indirect wholly owned subsidiary of Ally Financial Inc. and a leading franchise in the growing direct (internet, telephone, mobile, and mail) banking market.

Our accounting and reporting policies conform to accounting principles generally accepted in the United States of America (GAAP). Additionally, where applicable, the policies conform to the accounting and reporting guidelines prescribed by bank regulatory authorities. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and that affect income and expenses during the reporting period. In developing the estimates and assumptions, management uses all available evidence; however, actual results could differ.

The Condensed Consolidated Financial Statements at September 30, 2014, and for the three months and nine months ended September 30, 2014, and 2013, are unaudited but reflect all adjustments that are, in management’s opinion, necessary for the fair presentation of the results for the interim periods presented. All such adjustments are of a normal recurring nature. These unaudited Condensed Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements (and the related notes) included in our Annual Report on Form 10-K for the year ended December 31, 2013, as filed on March 3, 2014, with the U.S. Securities and Exchange Commission (SEC).

Initial Public Offering of Common Stock, Stock Split, and Changes in Number of Shares Authorized

In April 2014, we completed an initial public offering (IPO) of our common stock. All proceeds from the offering were obtained by the U.S. Department of the Treasury (Treasury) as the single selling stockholder. In connection with the IPO, we effected a 310-for-one stock split on shares of our common stock, $0.01 par value per share. Accordingly, all references in the Condensed Consolidated Financial Statements to share and per share amounts relating to common stock have been adjusted, on a retroactive basis, to recognize the 310-for-one stock split. In addition, on April 9, 2014, we increased the number of shares authorized for issuance of common stock to 1.1 billion and decreased the number of shares authorized for issuance of Series A Preferred Stock to approximately 41 million.

Significant Accounting Policies

Income Taxes

In calculating the provision for interim income taxes, in accordance with Accounting Standards Codification (ASC) 740, Income Taxes, we apply an estimated annual effective tax rate to year-to-date ordinary income. At the end of each interim period, we estimate the effective tax rate expected to be applicable for the full fiscal year. This method differs from that described in Note 1 to the Consolidated Financial Statements in our 2013 Annual Report on Form 10-K, which describes our annual significant income tax accounting policy and related methodology.

Refer to Note 1 to the Consolidated Financial Statements in our 2013 Annual Report on Form 10-K regarding additional significant accounting policies.

Recently Adopted Accounting Standards

Liabilities — Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation Is Fixed at the Reporting Date (ASU 2013-04)

As of January 1, 2014, we adopted Accounting Standards Update (ASU) 2013-04. The guidance within the ASU requires an entity to measure obligations resulting from joint and several liability arrangements for which the total amount of the obligation within the scope of this guidance is fixed at the reporting date, as the sum of the following: (a) The amount the reporting entity agreed to pay on the basis of its arrangement among its co-obligors and (b) any additional amount the reporting entity expects to pay on behalf of its co-obligors. The amendments were effective retrospectively for all arrangements within its scope. It further requires an entity to disclose the nature and amount of the obligation as well as other information about those obligations. The adoption of this guidance did not have a material effect on our consolidated financial condition or results of operations.

Foreign Currency Matters — Parent's Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entity (ASU 2013-05)

As of January 1, 2014, we adopted ASU 2013-05. The guidance within the ASU closes diversity in practice in this area and requires a reporting entity that ceases to have a controlling financial interest, in a subsidiary or group of assets or a business, within a foreign entity to release any related Cumulative Translation Adjustment (CTA) into net income. The CTA should be released into net income only if the sale or transfer results in the complete or substantially complete liquidation of the foreign entity. For an equity method investment that is a foreign entity, a pro rata portion of the CTA should be released into net income upon a partial sale of such an investment. This ASU further clarifies that the sale of an investment in a foreign entity includes both events that result in the loss of a controlling financial interest in a foreign entity, irrespective of any retained investment, and events that result in step acquisition under which an acquirer obtains control of an acquiree in which it held an equity interest immediately before the acquisition date. Under these circumstances, the CTA should be released into net income upon their occurrence. The amendments are to be applied prospectively for all transactions within its scope. Since the guidance is prospective and we have previously sold or exited substantially all of our international businesses and released the related CTA upon those dispositions, the adoption of this guidance did not have a material effect on our consolidated financial condition or results of operations.

Income Taxes — Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists (ASU 2013-11)

As of January 1, 2014, we adopted ASU 2013-11. The guidance within the ASU closes diversity in practice and requires an unrecognized tax benefit, or a portion of an unrecognized tax benefit, to be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward. The guidance further includes an exception that if a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available to settle any additional income taxes that would result from the disallowance of a tax position at the reporting date or the tax law of the applicable jurisdiction does not require the entity to use them and the entity does not intend to use them, the unrecognized tax benefit for such purpose should be presented in the financial statements as a liability and should not be combined with deferred tax assets. The assessment of whether a deferred tax asset is available is based on the unrecognized tax benefit and deferred tax asset that exist at the reporting date and should be made presuming disallowance of the tax position at the reporting date. The amendments are to be applied prospectively to all unrecognized tax benefits that exist at the effective date. The adoption of this guidance did not have a material effect to our consolidated financial condition or results of operations.

Investments — Accounting for Investments in Qualified Affordable Housing Projects (ASU 2014-01)

As of January 1, 2014, we adopted ASU 2014-01. The amendments in this ASU allow an entity to make an accounting policy election to account for investments in qualified affordable housing projects using a proportional amortization method, if certain conditions are met. Under the election, the entity would amortize the initial cost of the investment in proportion to the tax credits and other benefits received while recognizing the net investment performance in the statement of comprehensive income as a component of income tax expense. The amendments are to be applied retrospectively to all periods presented. We have elected to utilize the proportional amortization method for qualifying affordable housing investments and therefore will be presenting the amortization and tax impacts of such investments as a component of income tax expense under the proportional amortization method. The adoption of this guidance did not have a material effect to our consolidated financial condition or results of operations.

Recently Issued Accounting Standards

Receivables — Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure (ASU 2014-04)

In January 2014, the Financial Accounting Standards Board (FASB) issued ASU 2014-04. The amendments in this ASU clarify the timing for which an entity should reclassify a loan that has been foreclosed or where an in substance repossession has occurred to real estate owned. The guidance requires such reclassification to occur when the entity obtains legal title upon completion of foreclosure or the borrower conveys all interest in the residential real estate property to the entity to satisfy the loan through completion of a deed in lieu of foreclosure or similar legal agreement. In addition, the ASU clarifies that redemption rights of the borrower should be ignored for purposes of determining whether legal title has transferred. The amendments are effective for us beginning on January 1, 2015. The amendments can be applied using either a modified retrospective or prospective basis. Under the modified retrospective approach, the entity should record a cumulative-effect adjustment to residential consumer mortgage loans and residential real estate owned as of the beginning of the annual period for which the amendments are effective. Early adoption is permitted. Management is assessing the impact of the adoption of this guidance.

Presentation of Financial Statements and Property, Plant, and Equipment — Reporting Discontinued Operations and Disclosure of Disposals of Components of an Entity (ASU 2014-08)

In April 2014, the FASB issued ASU 2014-08. The amendments in this ASU modify the requirements for the reporting of discontinued operations. In order to qualify as a discontinued operation, the disposal of a component of an entity, a group of components, or a business of an entity must represent a strategic shift that has (or will have) a major effect on an entity’s operations and financial results. The ASU further indicates that the timing for recording a discontinued operation is when one of the following occurs: the component, group of components, or business meets the criteria to be classified as held for sale; the component, group of components, or business is disposed of by sale; or the component, group of components, or business is disposed of other than by sale (for example abandonment or spinoff). In addition, the ASU also requires additional disclosure items about an entity’s discontinued operations. The amendments are effective for us beginning on January 1, 2015. The amendments are to be applied prospectively solely to newly identified disposals that qualify as discontinued operations after the effective date. Items previously reported as discontinued operations will maintain their classification based on the prior guidance. Early adoption is permitted, but only for disposals that have not been previously reported as discontinued operations in previously issued financial statements. Because the guidance is prospective only for newly identified disposals that qualify as a discontinued operation, this guidance is not expected to have a material impact to our consolidated financial condition or results of operations upon adoption.

Revenue from Contracts with Customers (ASU 2014-09)

In May 2014, the FASB issued ASU 2014-09. The purpose of this guidance is to streamline and consolidate existing revenue recognition principles in GAAP and to converge revenue recognition principles with International Financial Reporting Standards (IFRS). The core principle of the amendments is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to receive in exchange for those goods or services. The amendments include a five step process for consideration of the main principle, guidance on accounting treatment for costs associated with a contract, and disclosure requirements related to the revenue process. The amendments are effective for us beginning on January 1, 2017. The amendments can be applied either through a full retrospective application or retrospectively with a cumulative effect adjustment on the date of initial adoption. Early adoption is prohibited. Management is assessing the impact of the adoption of this guidance.

Transfers and Servicing — Repurchase-to-Maturity Transactions, Repurchase Financings and Disclosures (ASU 2014-11)

In June 2014, the FASB issued ASU 2014-11. The amendments in this ASU change the accounting for repurchase to maturity transactions and repurchase financing transactions such that both will be reported as secured borrowings when the guidance becomes effective. In addition to the changes to how these transactions are reported, the ASU also includes new disclosure requirements. The amendments are effective for us beginning on January 1, 2015. The amendments are to be applied to all transactions that fall under the guidance as of the date of adoption with a cumulative effect adjustment recorded on the date of initial adoption. Early adoption is prohibited. The guidance is not expected to have a material impact to our consolidated financial condition or results of operations.