Interim Financial Statements (Policies)	3 Months Ended
Interim Financial Statements (Policies)	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The accompanying Unaudited Condensed Consolidated Financial Statements include the accounts of AutoNation, Inc. and its subsidiaries; all significant intercompany accounts and transactions have been eliminated.
Use Of Estimates	The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. In preparing these financial statements, management has made its best estimates and judgments of certain amounts included in the financial statements, giving due consideration to materiality. We base our estimates and judgments on historical experience and other assumptions that we believe are reasonable. However, application of these accounting policies involves the exercise of judgment and use of assumptions as to future uncertainties and, as a result, actual results could differ materially from these estimates. We periodically evaluate estimates and assumptions used in the preparation of the financial statements and make changes on a prospective basis when adjustments are necessary. Significant estimates made by AutoNation in the accompanying Unaudited Condensed Consolidated Financial Statements include certain assumptions related to goodwill, intangible assets, long-lived assets, assets held for sale, accruals for chargebacks against revenue recognized from the sale of finance and insurance products, accruals related to self-insurance programs, certain legal proceedings, estimated tax liabilities, and certain assumptions related to stock-based compensation.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Revenue Recognition In May 2014, the Financial Accounting Standards Board (“FASB”) issued an accounting standard update that amends the accounting guidance on revenue recognition. The amendments in this accounting standard update are intended to provide a more robust framework for addressing revenue issues, improve comparability of revenue recognition practices, and improve disclosure requirements. The amendments in this accounting standard update should be applied using either of the following transition methods: (i) a full retrospective approach reflecting the application of the standard in each prior reporting period with the option to elect certain practical expedients, or (ii) a retrospective approach with the cumulative effect of initially adopting the standard recognized at the date of adoption (which requires additional footnote disclosures). This accounting standard update is effective for interim and annual reporting periods beginning after December 15, 2016, with no early adoption permitted. However, the FASB recently agreed to propose a one-year deferral of the effective date for all entities along with the option to adopt the standard as of the original effective date. We are currently evaluating the method of adoption and the impact of the provisions of the accounting standard update. Presentation of Debt Issuance Costs In April 2015, the FASB issued an accounting standard update to simplify the presentation of debt issuance costs. The amendments in this accounting standard update require debt issuance costs be presented on the balance sheet as a direct reduction from the carrying amount of the related debt liability. The amendments in this accounting standard update are to be applied retrospectively and are effective for interim and annual reporting periods beginning after December 15, 2015. We do not expect the adoption of this accounting standard update to have a material impact on our balance sheet.

Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting. The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary.

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