<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>304</ContextCount>
  <ElementCount>301</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>87</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>10</UnitCount>
  <MyReports>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>9952151 - Statement - Unaudited Condensed Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/UnauditedCondensedConsolidatedBalanceSheets</Role>
      <ShortName>Unaudited Condensed Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>9952152 - Statement - Unaudited Condensed Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/UnauditedCondensedConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Unaudited Condensed Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>9952153 - Statement - Unaudited Condensed Consolidated Statements Of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/UnauditedCondensedConsolidatedStatementsOfIncome</Role>
      <ShortName>Unaudited Condensed Consolidated Statements Of Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>9952154 - Statement - Unaudited Condensed Consolidated Statement Of Shareholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/UnauditedCondensedConsolidatedStatementOfShareholdersEquity</Role>
      <ShortName>Unaudited Condensed Consolidated Statement Of Shareholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>9952155 - Statement - Unaudited Condensed Consolidated Statements Of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/UnauditedCondensedConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Unaudited Condensed Consolidated Statements Of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>9952157 - Disclosure - Interim Financial Statements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/InterimFinancialStatements</Role>
      <ShortName>Interim Financial Statements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>9952158 - Disclosure - Revenue Recognition</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/RevenueRecognition</Role>
      <ShortName>Revenue Recognition</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>9952159 - Disclosure - AutoNation Finance Income (Loss)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/AutoNationFinanceIncomeLoss</Role>
      <ShortName>AutoNation Finance Income (Loss)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>9952160 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/EarningsPerShare</Role>
      <ShortName>Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>9952161 - Disclosure - Receivables, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/ReceivablesNet</Role>
      <ShortName>Receivables, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>9952162 - Disclosure - Auto Loans Receivable</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/AutoLoansReceivable</Role>
      <ShortName>Auto Loans Receivable</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>9952163 - Disclosure - Inventory and Vehicle Floorplan Payable</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/InventoryandVehicleFloorplanPayable</Role>
      <ShortName>Inventory and Vehicle Floorplan Payable</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>9952164 - Disclosure - Goodwill and Intangible Assets, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/GoodwillandIntangibleAssetsNet</Role>
      <ShortName>Goodwill and Intangible Assets, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>9952165 - Disclosure - Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/Debt</Role>
      <ShortName>Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>9952166 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>9952167 - Disclosure - Shareholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/ShareholdersEquity</Role>
      <ShortName>Shareholders' Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>9952168 - Disclosure - Acquisitions and Divestitures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/AcquisitionsandDivestitures</Role>
      <ShortName>Acquisitions and Divestitures</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>9952169 - Disclosure - Cash Flow Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/CashFlowInformation</Role>
      <ShortName>Cash Flow Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>9952170 - Disclosure - Financial Instruments and Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/FinancialInstrumentsandFairValueMeasurements</Role>
      <ShortName>Financial Instruments and Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>9952171 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/CommitmentsandContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>9952172 - Disclosure - Business and Credit Concentrations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/BusinessandCreditConcentrations</Role>
      <ShortName>Business and Credit Concentrations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>9952173 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/SegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>995445 - Disclosure - Insider Trading Arrangements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements</Role>
      <ShortName>Insider Trading Arrangements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>9955511 - Disclosure - Interim Financial Statements (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/InterimFinancialStatementsPolicies</Role>
      <ShortName>Interim Financial Statements (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>9955512 - Disclosure - Revenue Recognition (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/RevenueRecognitionTables</Role>
      <ShortName>Revenue Recognition (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.autonation.com/role/RevenueRecognition</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>9955513 - Disclosure - AutoNation Finance Income (Loss) (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/AutoNationFinanceIncomeLossTables</Role>
      <ShortName>AutoNation Finance Income (Loss) (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.autonation.com/role/AutoNationFinanceIncomeLoss</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>9955514 - Disclosure - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/EarningsPerShareTables</Role>
      <ShortName>Earnings Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.autonation.com/role/EarningsPerShare</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>9955515 - Disclosure - Receivables, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/ReceivablesNetTables</Role>
      <ShortName>Receivables, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.autonation.com/role/ReceivablesNet</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>9955516 - Disclosure - Auto Loans Receivable (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/AutoLoansReceivableTables</Role>
      <ShortName>Auto Loans Receivable (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.autonation.com/role/AutoLoansReceivable</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>9955517 - Disclosure - Inventory and Vehicle Floorplan Payable (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/InventoryandVehicleFloorplanPayableTables</Role>
      <ShortName>Inventory and Vehicle Floorplan Payable (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.autonation.com/role/InventoryandVehicleFloorplanPayable</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>9955518 - Disclosure - Goodwill and Intangible Assets, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/GoodwillandIntangibleAssetsNetTables</Role>
      <ShortName>Goodwill and Intangible Assets, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.autonation.com/role/GoodwillandIntangibleAssetsNet</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>9955519 - Disclosure - Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/DebtTables</Role>
      <ShortName>Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.autonation.com/role/Debt</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>9955520 - Disclosure - Shareholders' Equity (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/ShareholdersEquityTables</Role>
      <ShortName>Shareholders' Equity (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.autonation.com/role/ShareholdersEquity</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>9955521 - Disclosure - Cash Flow Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/CashFlowInformationTables</Role>
      <ShortName>Cash Flow Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.autonation.com/role/CashFlowInformation</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>9955522 - Disclosure - Financial Instruments and Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/FinancialInstrumentsandFairValueMeasurementsTables</Role>
      <ShortName>Financial Instruments and Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.autonation.com/role/FinancialInstrumentsandFairValueMeasurements</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>9955523 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/SegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.autonation.com/role/SegmentInformation</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>9955524 - Disclosure - Interim Financial Statements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/InterimFinancialStatementsDetails</Role>
      <ShortName>Interim Financial Statements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/InterimFinancialStatementsPolicies</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>9955525 - Disclosure - Revenue Recognition (Disaggregation of Revenue) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/RevenueRecognitionDisaggregationofRevenueDetails</Role>
      <ShortName>Revenue Recognition (Disaggregation of Revenue) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/RevenueRecognitionTables</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>9955526 - Disclosure - Revenue Recognition (Estimated Revenue Expected to be Recognized In the Future) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/RevenueRecognitionEstimatedRevenueExpectedtobeRecognizedIntheFutureDetails</Role>
      <ShortName>Revenue Recognition (Estimated Revenue Expected to be Recognized In the Future) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/RevenueRecognitionTables</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>9955527 - Disclosure - Revenue Recognition (Contract Assets and Liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/RevenueRecognitionContractAssetsandLiabilitiesDetails</Role>
      <ShortName>Revenue Recognition (Contract Assets and Liabilities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/RevenueRecognitionTables</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>9955528 - Disclosure - AutoNation Finance Income (Loss) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/AutoNationFinanceIncomeLossDetails</Role>
      <ShortName>AutoNation Finance Income (Loss) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/AutoNationFinanceIncomeLossTables</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>9955529 - Disclosure - Earnings Per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/EarningsPerShareDetails</Role>
      <ShortName>Earnings Per Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/EarningsPerShareTables</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>9955530 - Disclosure - Receivables, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/ReceivablesNetDetails</Role>
      <ShortName>Receivables, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/ReceivablesNetTables</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>9955531 - Disclosure - Auto Loans Receivable - Components Of Receivables, Net Of Allowances For Expected Credit Losses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/AutoLoansReceivableComponentsOfReceivablesNetOfAllowancesForExpectedCreditLossesDetails</Role>
      <ShortName>Auto Loans Receivable - Components Of Receivables, Net Of Allowances For Expected Credit Losses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>9955532 - Disclosure - Auto Loans Receivable - Financing Receivable Credit Quality Indicators (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/AutoLoansReceivableFinancingReceivableCreditQualityIndicatorsDetails</Role>
      <ShortName>Auto Loans Receivable - Financing Receivable Credit Quality Indicators (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>9955533 - Disclosure - Auto Loans Receivable - Financing Receivable, Allowance for Credit Loss (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/AutoLoansReceivableFinancingReceivableAllowanceforCreditLossDetails</Role>
      <ShortName>Auto Loans Receivable - Financing Receivable, Allowance for Credit Loss (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>9955534 - Disclosure - Auto Loans Receivable - Financing Receivable, Past Due (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/AutoLoansReceivableFinancingReceivablePastDueDetails</Role>
      <ShortName>Auto Loans Receivable - Financing Receivable, Past Due (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>9955535 - Disclosure - Inventory and Vehicle Floorplan Payable (Components Of Inventory) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/InventoryandVehicleFloorplanPayableComponentsOfInventoryDetails</Role>
      <ShortName>Inventory and Vehicle Floorplan Payable (Components Of Inventory) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/InventoryandVehicleFloorplanPayableTables</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>9955536 - Disclosure - Inventory and Vehicle Floorplan Payable (Components Of Vehicle Floorplan Payable) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/InventoryandVehicleFloorplanPayableComponentsOfVehicleFloorplanPayableDetails</Role>
      <ShortName>Inventory and Vehicle Floorplan Payable (Components Of Vehicle Floorplan Payable) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/InventoryandVehicleFloorplanPayableTables</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>9955537 - Disclosure - Inventory and Vehicle Floorplan Payable (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/InventoryandVehicleFloorplanPayableNarrativeDetails</Role>
      <ShortName>Inventory and Vehicle Floorplan Payable (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/InventoryandVehicleFloorplanPayableTables</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>9955538 - Disclosure - Goodwill and Intangible Assets, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/GoodwillandIntangibleAssetsNetDetails</Role>
      <ShortName>Goodwill and Intangible Assets, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/GoodwillandIntangibleAssetsNetTables</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>9955539 - Disclosure - Debt (Long-Term Debt) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/DebtLongTermDebtDetails</Role>
      <ShortName>Debt (Long-Term Debt) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/DebtTables</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>9955540 - Disclosure - Long-Term Debt And Commercial Paper (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/LongTermDebtAndCommercialPaperNarrativeDetails</Role>
      <ShortName>Long-Term Debt And Commercial Paper (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>9955541 - Disclosure - Debt (Non-Recourse Debt) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/DebtNonRecourseDebtDetails</Role>
      <ShortName>Debt (Non-Recourse Debt) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/DebtTables</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>9955542 - Disclosure - Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/IncomeTaxesDetails</Role>
      <ShortName>Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/IncomeTaxes</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>9955543 - Disclosure - Shareholders' Equity (Shares Repurchased Under Stock Repurchase Program) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/ShareholdersEquitySharesRepurchasedUnderStockRepurchaseProgramDetails</Role>
      <ShortName>Shareholders' Equity (Shares Repurchased Under Stock Repurchase Program) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/ShareholdersEquityTables</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>9955544 - Disclosure - Shareholders' Equity (Preferred Stock) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/ShareholdersEquityPreferredStockDetails</Role>
      <ShortName>Shareholders' Equity (Preferred Stock) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/ShareholdersEquityTables</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>9955545 - Disclosure - Shareholders' Equity (Shares Issued And Shares Surrendered To Satisfy Tax Withholdings In Connection With Restricted Stock Units) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/ShareholdersEquitySharesIssuedAndSharesSurrenderedToSatisfyTaxWithholdingsInConnectionWithRestrictedStockUnitsDetails</Role>
      <ShortName>Shareholders' Equity (Shares Issued And Shares Surrendered To Satisfy Tax Withholdings In Connection With Restricted Stock Units) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/ShareholdersEquityTables</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>9955546 - Disclosure - Acquisitions and Divestitures (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/AcquisitionsandDivestituresDetails</Role>
      <ShortName>Acquisitions and Divestitures (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/AcquisitionsandDivestitures</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>9955547 - Disclosure - Cash Flow Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/CashFlowInformationDetails</Role>
      <ShortName>Cash Flow Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/CashFlowInformationTables</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>9955548 - Disclosure - Financial Instruments and Fair Value Measurements (Summary Of Carrying Values and Fair Values Of Fixed Rate Debt) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/FinancialInstrumentsandFairValueMeasurementsSummaryOfCarryingValuesandFairValuesOfFixedRateDebtDetails</Role>
      <ShortName>Financial Instruments and Fair Value Measurements (Summary Of Carrying Values and Fair Values Of Fixed Rate Debt) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/FinancialInstrumentsandFairValueMeasurementsTables</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>9955549 - Disclosure - Financial Instruments and Fair Value Measurements (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/FinancialInstrumentsandFairValueMeasurementsNarrativeDetails</Role>
      <ShortName>Financial Instruments and Fair Value Measurements (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/FinancialInstrumentsandFairValueMeasurementsTables</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>9955550 - Disclosure - Financial Instruments and Fair Value Measurements (Assets Measured on a Nonrecurring Basis) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/FinancialInstrumentsandFairValueMeasurementsAssetsMeasuredonaNonrecurringBasisDetails</Role>
      <ShortName>Financial Instruments and Fair Value Measurements (Assets Measured on a Nonrecurring Basis) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/FinancialInstrumentsandFairValueMeasurementsTables</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>9955551 - Disclosure - Commitments and Contingencies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/CommitmentsandContingenciesDetails</Role>
      <ShortName>Commitments and Contingencies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/CommitmentsandContingencies</ParentRole>
      <Position>65</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>9955552 - Disclosure - Business and Credit Concentrations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/BusinessandCreditConcentrationsDetails</Role>
      <ShortName>Business and Credit Concentrations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/BusinessandCreditConcentrations</ParentRole>
      <Position>66</Position>
    </Report>
    <Report instance="an-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>9955553 - Disclosure - Segment Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.autonation.com/role/SegmentInformationDetails</Role>
      <ShortName>Segment Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.autonation.com/role/SegmentInformationTables</ParentRole>
      <Position>67</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-Q" isDefinitelyFs="true" isUsgaap="true" original="an-20260331.htm">an-20260331.htm</File>
    <File>an-20260331.xsd</File>
    <File>an-20260331_cal.xml</File>
    <File>an-20260331_def.xml</File>
    <File>an-20260331_lab.xml</File>
    <File>an-20260331_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="837">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="29">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="4">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
