<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>532</ContextCount>
  <ElementCount>688</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>140</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>6</UnitCount>
  <MyReports>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>75000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/documentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>75010 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/StatementConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>75020 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/StatementConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>75030 - Statement - Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/StatementConsolidatedStatementsOfOperations</Role>
      <ShortName>Consolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>75040 - Statement - Consolidated Statements of Operations (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/StatementConsolidatedStatementsOfOperationsParenthetical</Role>
      <ShortName>Consolidated Statements of Operations (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>75050 - Statement - Consolidated Statements of Comprehensive Income (Loss)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/StatementConsolidatedStatementsOfComprehensiveIncomeLoss</Role>
      <ShortName>Consolidated Statements of Comprehensive Income (Loss)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>75060 - Statement - Consolidated Statements of Changes in Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/statementOfChangesInStockholdersEquity</Role>
      <ShortName>Consolidated Statements of Changes in Stockholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>75080 - Statement - Condensed Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/statementOfCashFlows</Role>
      <ShortName>Condensed Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>75090 - Statement - Supplemental Disclosure of Cash Flow Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/StatementSupplementalDisclosureOfCashFlowInformation</Role>
      <ShortName>Supplemental Disclosure of Cash Flow Information</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>995410 - Disclosure - Pay vs Performance Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/PvpDisclosure</Role>
      <ShortName>Pay vs Performance Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>995455 - Disclosure - Basis of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsBasisOfPresentation</Role>
      <ShortName>Basis of Presentation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>995465 - Disclosure - Principles of Consolidation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsPrinciplesOfConsolidation</Role>
      <ShortName>Principles of Consolidation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>995475 - Disclosure - Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsAccountingPolicies</Role>
      <ShortName>Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>995485 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsEarningsPerShare</Role>
      <ShortName>Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>995495 - Disclosure - Trade Receivables and Reinsurance Recoverables, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureTradeReceivablesAndReinsuranceRecoverablesNet</Role>
      <ShortName>Trade Receivables and Reinsurance Recoverables, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>995505 - Disclosure - Investments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsInvestments</Role>
      <ShortName>Investments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>995515 - Disclosure - Other Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsOtherAssets</Role>
      <ShortName>Other Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>995525 - Disclosure - Accounts Payable and Accrued Expense</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureAccountsPayableAndAccruedExpense</Role>
      <ShortName>Accounts Payable and Accrued Expense</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>995535 - Disclosure - Net Investment and Interest Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsNetInvestmentAndInterestIncome</Role>
      <ShortName>Net Investment and Interest Income</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>995545 - Disclosure - Borrowings</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsBorrowings</Role>
      <ShortName>Borrowings</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>995555 - Disclosure - Interest on Borrowings</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsInterestOnBorrowings</Role>
      <ShortName>Interest on Borrowings</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>995565 - Disclosure - Derivatives</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsDerivativesPolicy</Role>
      <ShortName>Derivatives</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>995575 - Disclosure - Accumulated Other Comprehensive Income (Loss)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeLoss1</Role>
      <ShortName>Accumulated Other Comprehensive Income (Loss)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>995585 - Disclosure - Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/stockholdersEquity</Role>
      <ShortName>Stockholders' Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>995595 - Disclosure - Provision for Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsProvisionForTaxes</Role>
      <ShortName>Provision for Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>995605 - Disclosure - Employee Benefit Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedEmployeeBenefitPlans</Role>
      <ShortName>Employee Benefit Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>995615 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>995625 - Disclosure - Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedLeases</Role>
      <ShortName>Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>995635 - Disclosure - Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedStatementsContingencies</Role>
      <ShortName>Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>995645 - Disclosure - Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsRelatedPartyTransactions</Role>
      <ShortName>Related Party Transactions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>995655 - Disclosure - Reportable Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureReportableSegmentInformation</Role>
      <ShortName>Reportable Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>995665 - Disclosure - Geographic Area Data</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureGeographicAreaData1</Role>
      <ShortName>Geographic Area Data</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>995675 - Disclosure - Revenue Recognition</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsRevenueRecognition</Role>
      <ShortName>Revenue Recognition</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>995685 - Disclosure - Allowance for Credit Losses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsAllowanceForCreditLosses</Role>
      <ShortName>Allowance for Credit Losses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>995695 - Disclosure - Reinsurance and Policy Benefits and Losses, Claims and Loss Expenses Payable</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsReinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensePayable</Role>
      <ShortName>Reinsurance and Policy Benefits and Losses, Claims and Loss Expenses Payable</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>995705 - Disclosure - Deferred Policy Acquisition Costs, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureDeferredPolicyAcquisitionCostsNet</Role>
      <ShortName>Deferred Policy Acquisition Costs, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>995715 - Disclosure - Life Insurance Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureLifeInsuranceLiabilities1</Role>
      <ShortName>Life Insurance Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>995725 - Disclosure - Statutory Financial Information of Insurance Subsidiaries</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsStatutoryFinancialInformationOfInsruanceSubsidiaries</Role>
      <ShortName>Statutory Financial Information of Insurance Subsidiaries</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>995735 - Disclosure - Schedule II - U-Haul Holding Company and Consolidated Subsidiaries Valuation and Qualifying Accounts</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsUHaulHoldingCompanyAndConsolidatedSubsidiariesValuationAndQualifyingAccounts</Role>
      <ShortName>Schedule II - U-Haul Holding Company and Consolidated Subsidiaries Valuation and Qualifying Accounts</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>995745 - Disclosure - Schedule V - Supplemental Information (for Property-Casualty Insurance Operations)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsSupplementalInformation</Role>
      <ShortName>Schedule V - Supplemental Information (for Property-Casualty Insurance Operations)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>995755 - Disclosure - Accounting Policies (Policy Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/accountingPoliciesPolicyTextBlock</Role>
      <ShortName>Accounting Policies (Policy Text Block)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsAccountingPolicies</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>995765 - Disclosure - Accounting Policies (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/AccountingPoliciesTableTextBlock</Role>
      <ShortName>Accounting Policies (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsAccountingPolicies</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>995775 - Disclosure - Earnings Per Share (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureEarningsPerShareTableTextBlock</Role>
      <ShortName>Earnings Per Share (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsEarningsPerShare</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>995785 - Disclosure - Trade Receivables and Reinsurance Recoverables, Net (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureTradeReceivablesAndReinsuranceRecoverablesNetTableTextBlock</Role>
      <ShortName>Trade Receivables and Reinsurance Recoverables, Net (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureTradeReceivablesAndReinsuranceRecoverablesNet</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>995795 - Disclosure - Investments (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/InvestmentsTableTextBlock</Role>
      <ShortName>Investments (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsInvestments</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>995805 - Disclosure - Other Assets (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/otherAssetsTableTextBlock</Role>
      <ShortName>Other Assets (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsOtherAssets</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>995815 - Disclosure - Accounts Payable and Accrued Expense (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureAccountsPayableAndAccruedExpenseTableTextBlock</Role>
      <ShortName>Accounts Payable and Accrued Expense (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureAccountsPayableAndAccruedExpense</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>995825 - Disclosure - Net Investment and Interest Income (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/netInvestmentAndInterestIncomeTableTextBlock</Role>
      <ShortName>Net Investment and Interest Income (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsNetInvestmentAndInterestIncome</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>995835 - Disclosure - Notes, Loans and Finance Leases Payable, net (Table Text Block)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureNotesLoansAndFinanceLeasesPayableNetTableTextBlock</Role>
      <ShortName>Notes, Loans and Finance Leases Payable, net (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>995845 - Disclosure - Interest on Borrowings (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/InterestOnBorrowingsTableTextBlock</Role>
      <ShortName>Interest on Borrowings (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsInterestOnBorrowings</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>995855 - Disclosure - Derivatives (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/derivativesTableTextBlock</Role>
      <ShortName>Derivatives (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsDerivativesPolicy</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>995865 - Disclosure - Accumulated Other Comprehensive Income (Loss) (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeLossTableTextBlock</Role>
      <ShortName>Accumulated Other Comprehensive Income (Loss) (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeLoss1</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>995875 - Disclosure - Stockholders' Equity (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/stockholdersEquityTableTextBlock</Role>
      <ShortName>Stockholders' Equity (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/stockholdersEquity</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>995885 - Disclosure - Provision for Taxes (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/provisionForTaxesTableTextBlock</Role>
      <ShortName>Provision for Taxes (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsProvisionForTaxes</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>995895 - Disclosure - Employee Benefit Plans (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/EmployeeBenefitPlansTableTextBlock</Role>
      <ShortName>Employee Benefit Plans (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedEmployeeBenefitPlans</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>995905 - Disclosure - Fair Value Measurements (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/FairValueMeasurementsTableTextBlock</Role>
      <ShortName>Fair Value Measurements (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFairValueMeasurements</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>995915 - Disclosure - Leases (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/LeasesTableTextBlock</Role>
      <ShortName>Leases (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedLeases</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>995925 - Disclosure - Related Party Transactions (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/RelatedPartyTransactionsTableTextBlock</Role>
      <ShortName>Related Party Transactions (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsRelatedPartyTransactions</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>995935 - Disclosure - Reportable Segment Information (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureReportableSegmentInformationTableTextBlock</Role>
      <ShortName>Reportable Segment Information (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureReportableSegmentInformation</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>995945 - Disclosure - Geographic Area Data (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureGeographicAreaDataTableTextBlock</Role>
      <ShortName>Geographic Area Data (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureGeographicAreaData1</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>995955 - Disclosure - Revenue Recognition (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/RevenueRecognitionTableTextBlock</Role>
      <ShortName>Revenue Recognition (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsRevenueRecognition</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>995965 - Disclosure - Reinsurance and Policy Benefits and Losses, Claims and Loss Expenses Payable (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/reinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensesPayableTableTextBlock</Role>
      <ShortName>Reinsurance and Policy Benefits and Losses, Claims and Loss Expenses Payable (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsReinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensePayable</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>995975 - Disclosure - Deferred Policy Acquisition Costs, Net (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureDeferredPolicyAcquisitionCostsNetTableTextBlock</Role>
      <ShortName>Deferred Policy Acquisition Costs, Net (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureDeferredPolicyAcquisitionCostsNet</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>995985 - Disclosure - Life Insurance Liabilities (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureLifeInsuranceLiabilitiesTableTextBlock</Role>
      <ShortName>Life Insurance Liabilities (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureLifeInsuranceLiabilities1</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>995995 - Disclosure - Statutory Financial Information of Insurance Subsidiaries (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/statutoryFinancialInformationOfInsuranceSubsidiariesTableTextBlock</Role>
      <ShortName>Statutory Financial Information of Insurance Subsidiaries (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsStatutoryFinancialInformationOfInsruanceSubsidiaries</ParentRole>
      <Position>65</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>996005 - Disclosure - Allowance for Credit Losses (Table Text Block)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/AllowanceForCreditLossesTableTextBlock</Role>
      <ShortName>Allowance for Credit Losses (Table Text Block)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsAllowanceForCreditLosses</ParentRole>
      <Position>66</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>996015 - Disclosure - Basis of Presentation - (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureBasisOfPresentationNarrativesDetails</Role>
      <ShortName>Basis of Presentation - (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsBasisOfPresentation</ParentRole>
      <Position>67</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>996025 - Disclosure - Principles of Consolidation (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/PrinciplesOfConsolidationNarrativesDetails</Role>
      <ShortName>Principles of Consolidation (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/notesToConsolidatedFinancialStatementsPrinciplesOfConsolidation</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>996035 - Disclosure - Accounting Policies (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/AccountingPoliciesNarrativesDetails</Role>
      <ShortName>Accounting Policies (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/AccountingPoliciesTableTextBlock</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>996045 - Disclosure - Accounting Policies (Inventories, net) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/AccountingPoliciesInventoriesNetDetails</Role>
      <ShortName>Accounting Policies (Inventories, net) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/AccountingPoliciesTableTextBlock</ParentRole>
      <Position>70</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>996055 - Disclosure - Earnings Per Share (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/EarningsPerShareNarrativesDetails</Role>
      <ShortName>Earnings Per Share (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureEarningsPerShareTableTextBlock</ParentRole>
      <Position>71</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>996065 - Disclosure - Earnings Per Share Calculation Basic Diluted Earnings Per Share Voting Non Voting Common Stock (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/EarningsPerShareCalculationBasicDilutedEarningsPerShareVotingNonVotingCommonStockDetails</Role>
      <ShortName>Earnings Per Share Calculation Basic Diluted Earnings Per Share Voting Non Voting Common Stock (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>996075 - Disclosure - Trade Receivables and Reinsurance Recoverables, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureTradeReceivablesAndReinsuranceRecoverablesNetDetails</Role>
      <ShortName>Trade Receivables and Reinsurance Recoverables, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureTradeReceivablesAndReinsuranceRecoverablesNetTableTextBlock</ParentRole>
      <Position>73</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>996085 - Disclosure - Investments (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/InvestmentsNarrativesDetails</Role>
      <ShortName>Investments (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/InvestmentsTableTextBlock</ParentRole>
      <Position>74</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>996095 - Disclosure - Investments (Available For Sale Investments) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureInvestmentsAvailableForSaleInvestmentsDetails</Role>
      <ShortName>Investments (Available For Sale Investments) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/InvestmentsTableTextBlock</ParentRole>
      <Position>75</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>996105 - Disclosure - Investments (Available-for-sale investments with unrealized losses) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureInvestmentsAvailableforsaleInvestmentsWithUnrealizedLossesDetails</Role>
      <ShortName>Investments (Available-for-sale investments with unrealized losses) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/InvestmentsTableTextBlock</ParentRole>
      <Position>76</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>996115 - Disclosure - Investments (Adjusted cost and estimated market value of available-for-sale investments) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureInvestmentsAdjustedCostAndEstimatedMarketValueOfAvailableforsaleInvestmentsDetails</Role>
      <ShortName>Investments (Adjusted cost and estimated market value of available-for-sale investments) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/InvestmentsTableTextBlock</ParentRole>
      <Position>77</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>996125 - Disclosure - Investments (Available for sale equity investments) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/InvestmentsAvailableForSaleEquityInvestmentsDetails</Role>
      <ShortName>Investments (Available for sale equity investments) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/InvestmentsTableTextBlock</ParentRole>
      <Position>78</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>996135 - Disclosure - Investments (Carrying value of other investments) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/InvestmentsCarryingValueOfOtherInvestmentsDetails</Role>
      <ShortName>Investments (Carrying value of other investments) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/InvestmentsTableTextBlock</ParentRole>
      <Position>79</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>996145 - Disclosure - Other Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/otherAssetsDetails</Role>
      <ShortName>Other Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/otherAssetsTableTextBlock</ParentRole>
      <Position>80</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>996155 - Disclosure - Accounts Payable and Accrued Expenses and Other Reserves (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureAccountsPayableAndAccruedExpensesAndOtherReservesNarrativesDetails</Role>
      <ShortName>Accounts Payable and Accrued Expenses and Other Reserves (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>81</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>996165 - Disclosure - Accounts Payable and Accrued Expenses and Other Reserves Accounts payable and accrued expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureAccountsPayableAndAccruedExpensesAndOtherReservesAccountsPayableAndAccruedExpensesDetails</Role>
      <ShortName>Accounts Payable and Accrued Expenses and Other Reserves Accounts payable and accrued expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>996175 - Disclosure - Net Investment and Interest Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/netInvestmentAndInterestIncomeDetails</Role>
      <ShortName>Net Investment and Interest Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/netInvestmentAndInterestIncomeTableTextBlock</ParentRole>
      <Position>83</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>996185 - Disclosure - Notes, Loans and Finance Leases Payable, net (Narratives) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureNotesLoansAndFinanceLeasesPayableNetNarrativesDetails</Role>
      <ShortName>Notes, Loans and Finance Leases Payable, net (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureNotesLoansAndFinanceLeasesPayableNetTableTextBlock</ParentRole>
      <Position>84</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>996195 - Disclosure - Notes, Loans and Finance Leases Payable, net (Long-term Debt Borrowings) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureNotesLoansAndFinanceLeasesPayableNetLongtermDebtBorrowingsDetails</Role>
      <ShortName>Notes, Loans and Finance Leases Payable, net (Long-term Debt Borrowings) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureNotesLoansAndFinanceLeasesPayableNetTableTextBlock</ParentRole>
      <Position>85</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>996205 - Disclosure - Notes, Loans and Finance Leases Payable, net (Long-term Debt Borrowings) (Parenthetical) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureNotesLoansAndFinanceLeasesPayableNetLongtermDebtBorrowingsParentheticalDetails</Role>
      <ShortName>Notes, Loans and Finance Leases Payable, net (Long-term Debt Borrowings) (Parenthetical) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureNotesLoansAndFinanceLeasesPayableNetTableTextBlock</ParentRole>
      <Position>86</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>996215 - Disclosure - Notes, Loans and Finance Leases Payable, net (Annual Maturities of Notes, Loans and Leases Payable) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureNotesLoansAndFinanceLeasesPayableNetAnnualMaturitiesOfNotesLoansAndLeasesPayableDetails</Role>
      <ShortName>Notes, Loans and Finance Leases Payable, net (Annual Maturities of Notes, Loans and Leases Payable) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureNotesLoansAndFinanceLeasesPayableNetTableTextBlock</ParentRole>
      <Position>87</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>996225 - Disclosure - Interest on Notes, Loans and Finance Leases Payable, net (Narratives) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureInterestOnNotesLoansAndFinanceLeasesPayableNetNarrativesDetails</Role>
      <ShortName>Interest on Notes, Loans and Finance Leases Payable, net (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>88</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>996235 - Disclosure - Interest on Notes, Loans and Finance Leases Payable, net (Components of Interest Expense) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureInterestOnNotesLoansAndFinanceLeasesPayableNetComponentsOfInterestExpenseDetails</Role>
      <ShortName>Interest on Notes, Loans and Finance Leases Payable, net (Components of Interest Expense) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>89</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>996245 - Disclosure - Interest on Notes, Loans and Finance Leases Payable, net (Interest Rates and Company Borrowings) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureInterestOnNotesLoansAndFinanceLeasesPayableNetInterestRatesAndCompanyBorrowingsDetails</Role>
      <ShortName>Interest on Notes, Loans and Finance Leases Payable, net (Interest Rates and Company Borrowings) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>90</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>996255 - Disclosure - Derivatives (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DerivativesNarrativesDetails</Role>
      <ShortName>Derivatives (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/derivativesTableTextBlock</ParentRole>
      <Position>91</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>996265 - Disclosure - Derivatives (Interest Rate Contracts Designated as Hedging Instruments) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureDerivativesInterestRateContractsDesignatedAsHedgingInstrumentsDetails</Role>
      <ShortName>Derivatives (Interest Rate Contracts Designated as Hedging Instruments) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/derivativesTableTextBlock</ParentRole>
      <Position>92</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>996275 - Disclosure - Derivatives (Equity Market Contracts Designated As Hedging Instruments) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DerivativesEquityMarketContractsDesignatedAsHedgingInstrumentsDetails</Role>
      <ShortName>Derivatives (Equity Market Contracts Designated As Hedging Instruments) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/derivativesTableTextBlock</ParentRole>
      <Position>93</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>996285 - Disclosure - Accumulated Other Comprehensive Income (Loss) (Summary of Accumulated Other Comprehensive Income (Loss) Components, Net of Tax) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeLossSummaryOfAccumulatedOtherComprehensiveIncomeLossComponentsNetOfTaxDetails</Role>
      <ShortName>Accumulated Other Comprehensive Income (Loss) (Summary of Accumulated Other Comprehensive Income (Loss) Components, Net of Tax) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeLossTableTextBlock</ParentRole>
      <Position>94</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>996295 - Disclosure - Dividends - Summary of Dividends Declared (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureDividendsSummaryOfDividendsDeclaredDetails</Role>
      <ShortName>Dividends - Summary of Dividends Declared (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>95</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>996305 - Disclosure - Provision for Taxes (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/ProvisionForTaxesNarrativesDetails</Role>
      <ShortName>Provision for Taxes (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/provisionForTaxesTableTextBlock</ParentRole>
      <Position>96</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>996315 - Disclosure - Provision for Taxes (Earnings Before Taxes and Provision for Taxes) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureProvisionForTaxesEarningsBeforeTaxesAndProvisionForTaxesDetails</Role>
      <ShortName>Provision for Taxes (Earnings Before Taxes and Provision for Taxes) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/provisionForTaxesTableTextBlock</ParentRole>
      <Position>97</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R98.htm</HtmlFileName>
      <LongName>996325 - Disclosure - Provision for Taxes (Income taxes paid, net) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureProvisionForTaxesIncomeTaxesPaidNetDetails</Role>
      <ShortName>Provision for Taxes (Income taxes paid, net) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/provisionForTaxesTableTextBlock</ParentRole>
      <Position>98</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R99.htm</HtmlFileName>
      <LongName>996335 - Disclosure - Provision for Taxes - (Income taxes paid, jurisdiction exceeding 5% of total) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureProvisionForTaxesIncomeTaxesPaidJurisdictionExceeding5OfTotalDetails</Role>
      <ShortName>Provision for Taxes - (Income taxes paid, jurisdiction exceeding 5% of total) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/provisionForTaxesTableTextBlock</ParentRole>
      <Position>99</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R100.htm</HtmlFileName>
      <LongName>996345 - Disclosure - Provision for Taxes (Effective Income Tax Rate Reconciliation) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureProvisionForTaxesEffectiveIncomeTaxRateReconciliationDetails</Role>
      <ShortName>Provision for Taxes (Effective Income Tax Rate Reconciliation) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/provisionForTaxesTableTextBlock</ParentRole>
      <Position>100</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R101.htm</HtmlFileName>
      <LongName>996355 - Disclosure - Provision for Taxes (Significant Components of Deferred Tax Assets and Liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureProvisionForTaxesSignificantComponentsOfDeferredTaxAssetsAndLiabilitiesDetails</Role>
      <ShortName>Provision for Taxes (Significant Components of Deferred Tax Assets and Liabilities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/provisionForTaxesTableTextBlock</ParentRole>
      <Position>101</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R102.htm</HtmlFileName>
      <LongName>996365 - Disclosure - Provision for Taxes (Reconciliation of Total Amounts of Unrecognized Tax Benefits Roll Forward) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureProvisionForTaxesReconciliationOfTotalAmountsOfUnrecognizedTaxBenefitsRollForwardDetails</Role>
      <ShortName>Provision for Taxes (Reconciliation of Total Amounts of Unrecognized Tax Benefits Roll Forward) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/provisionForTaxesTableTextBlock</ParentRole>
      <Position>102</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R103.htm</HtmlFileName>
      <LongName>996375 - Disclosure - Employee Benefit Plans (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/EmployeeBenefitPlansNarrativesDetails</Role>
      <ShortName>Employee Benefit Plans (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/EmployeeBenefitPlansTableTextBlock</ParentRole>
      <Position>103</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R104.htm</HtmlFileName>
      <LongName>996385 - Disclosure - Employee Benefit Plans (Shares Held by the ESOP Plan) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/EmployeeBenefitPlansSharesHeldByTheESOPPlanDetails</Role>
      <ShortName>Employee Benefit Plans (Shares Held by the ESOP Plan) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/EmployeeBenefitPlansTableTextBlock</ParentRole>
      <Position>104</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R105.htm</HtmlFileName>
      <LongName>996395 - Disclosure - Employee Benefit Plans (Components of Net Periodic Post Retirement Benefit Cost) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureEmployeeBenefitPlansComponentsOfNetPeriodicPostRetirementBenefitCostDetails</Role>
      <ShortName>Employee Benefit Plans (Components of Net Periodic Post Retirement Benefit Cost) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/EmployeeBenefitPlansTableTextBlock</ParentRole>
      <Position>105</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R106.htm</HtmlFileName>
      <LongName>996405 - Disclosure - Employee Benefit Plans (Components of Postretirement Benefit Liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/EmployeeBenefitPlansComponentsOfPostretirementBenefitLiabilitiesDetails</Role>
      <ShortName>Employee Benefit Plans (Components of Postretirement Benefit Liabilities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/EmployeeBenefitPlansTableTextBlock</ParentRole>
      <Position>106</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R107.htm</HtmlFileName>
      <LongName>996415 - Disclosure - Employee Benefit Plans (Discount Rate Assumptions in Computation of Accumulated Postretirement Benefit Obligation) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/EmployeeBenefitPlansDiscountRateAssumptionsInComputationOfAccumulatedPostretirementBenefitObligationDetails</Role>
      <ShortName>Employee Benefit Plans (Discount Rate Assumptions in Computation of Accumulated Postretirement Benefit Obligation) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/EmployeeBenefitPlansTableTextBlock</ParentRole>
      <Position>107</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R108.htm</HtmlFileName>
      <LongName>996425 - Disclosure - Employee Benefit Plans (Future Net Benefit Payments Expected for Post Employee Benefit Obligations) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/EmployeeBenefitPlansFutureNetBenefitPaymentsExpectedForPostEmployeeBenefitObligationsDetails</Role>
      <ShortName>Employee Benefit Plans (Future Net Benefit Payments Expected for Post Employee Benefit Obligations) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/EmployeeBenefitPlansTableTextBlock</ParentRole>
      <Position>108</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R109.htm</HtmlFileName>
      <LongName>996435 - Disclosure - Fair Value Measurements (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureFairValueMeasurementsNarrativesDetails</Role>
      <ShortName>Fair Value Measurements (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/FairValueMeasurementsTableTextBlock</ParentRole>
      <Position>109</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R110.htm</HtmlFileName>
      <LongName>996445 - Disclosure - Fair Value Measurements (Financial instruments level within the fair value hierarchy) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureFairValueMeasurementsFinancialInstrumentsLevelWithinTheFairValueHierarchyDetails</Role>
      <ShortName>Fair Value Measurements (Financial instruments level within the fair value hierarchy) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/FairValueMeasurementsTableTextBlock</ParentRole>
      <Position>110</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R111.htm</HtmlFileName>
      <LongName>996455 - Disclosure - Fair Value Measurements (Carrying and Estimated Fair Values within Fair Value Hierarchy) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureFairValueMeasurementsCarryingAndEstimatedFairValuesWithinFairValueHierarchyDetails</Role>
      <ShortName>Fair Value Measurements (Carrying and Estimated Fair Values within Fair Value Hierarchy) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/FairValueMeasurementsTableTextBlock</ParentRole>
      <Position>111</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R112.htm</HtmlFileName>
      <LongName>996465 - Disclosure - Leases (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/LeasesNarrativesDetails</Role>
      <ShortName>Leases (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/LeasesTableTextBlock</ParentRole>
      <Position>112</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R113.htm</HtmlFileName>
      <LongName>996475 - Disclosure - Leases (Components of our right-of-use assets) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureLeasesComponentsOfOurRightofuseAssetsDetails</Role>
      <ShortName>Leases (Components of our right-of-use assets) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/LeasesTableTextBlock</ParentRole>
      <Position>113</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R114.htm</HtmlFileName>
      <LongName>996485 - Disclosure - Leases (Finance Leases Weighted Average Remaining Lease Term and Discount Rate) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/LeasesFinanceLeasesWeightedAverageTermAndDiscountRateDetails</Role>
      <ShortName>Leases (Finance Leases Weighted Average Remaining Lease Term and Discount Rate) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/LeasesTableTextBlock</ParentRole>
      <Position>114</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R115.htm</HtmlFileName>
      <LongName>996495 - Disclosure - Leases (Operating Leases Weighted Average Remaining Lease Term and Discount Rate) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/LeasesOperatingLeasesWeightedAverageTermAndDiscountRateDetails</Role>
      <ShortName>Leases (Operating Leases Weighted Average Remaining Lease Term and Discount Rate) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/LeasesTableTextBlock</ParentRole>
      <Position>115</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R116.htm</HtmlFileName>
      <LongName>996505 - Disclosure - Leases (Components Of Lease Expense) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/LeasesComponentsOfLeaseExpenseDetails</Role>
      <ShortName>Leases (Components Of Lease Expense) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/LeasesTableTextBlock</ParentRole>
      <Position>116</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R117.htm</HtmlFileName>
      <LongName>996515 - Disclosure - Leases (Maturities Of Lease Liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/LeasesMaturitiesOfLeaseLiabilitiesDetails</Role>
      <ShortName>Leases (Maturities Of Lease Liabilities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/LeasesTableTextBlock</ParentRole>
      <Position>117</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R118.htm</HtmlFileName>
      <LongName>996525 - Disclosure - Related Party Transactions (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/RelatedPartyTransactionsNarrativesDetails</Role>
      <ShortName>Related Party Transactions (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/RelatedPartyTransactionsTableTextBlock</ParentRole>
      <Position>118</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R119.htm</HtmlFileName>
      <LongName>996535 - Disclosure - Related Party Transactions - (Related Party Revenue) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureRelatedPartyTransactionsRelatedPartyRevenueDetails</Role>
      <ShortName>Related Party Transactions - (Related Party Revenue) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/RelatedPartyTransactionsTableTextBlock</ParentRole>
      <Position>119</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R120.htm</HtmlFileName>
      <LongName>996545 - Disclosure - Related Party Transactions (Related Party Costs and Expenses) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/RelatedPartyTransactionsRelatedPartyCostsAndExpensesDetails</Role>
      <ShortName>Related Party Transactions (Related Party Costs and Expenses) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/RelatedPartyTransactionsTableTextBlock</ParentRole>
      <Position>120</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R121.htm</HtmlFileName>
      <LongName>996555 - Disclosure - Related Party Transactions (Related Party Assets) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/RelatedPartyTransactionsRelatedPartyAssetsDetails</Role>
      <ShortName>Related Party Transactions (Related Party Assets) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/RelatedPartyTransactionsTableTextBlock</ParentRole>
      <Position>121</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R122.htm</HtmlFileName>
      <LongName>996565 - Disclosure - Reportable Segment Information - Revenues and Earnings from Operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureReportableSegmentInformationRevenuesAndEarningsFromOperationsDetails</Role>
      <ShortName>Reportable Segment Information - Revenues and Earnings from Operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>122</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R123.htm</HtmlFileName>
      <LongName>996575 - Disclosure - Reportable Segment Information - Gross Capital Expenditures (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureReportableSegmentInformationGrossCapitalExpendituresDetails</Role>
      <ShortName>Reportable Segment Information - Gross Capital Expenditures (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>123</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R124.htm</HtmlFileName>
      <LongName>996585 - Disclosure - Reportable Segment Information - Assets by Operating Segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureReportableSegmentInformationAssetsByOperatingSegmentDetails</Role>
      <ShortName>Reportable Segment Information - Assets by Operating Segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>124</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R125.htm</HtmlFileName>
      <LongName>996595 - Disclosure - Financial Information by Geographic Area (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/FinancialInformationByGeographicAreaDetails</Role>
      <ShortName>Financial Information by Geographic Area (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>125</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R126.htm</HtmlFileName>
      <LongName>996605 - Disclosure - Revenue Recognition (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureRevenueRecognitionNarrativesDetails</Role>
      <ShortName>Revenue Recognition (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/RevenueRecognitionTableTextBlock</ParentRole>
      <Position>126</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R127.htm</HtmlFileName>
      <LongName>996615 - Disclosure - Revenue Recognition (Revenue Over Time) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/RevenueRecognitionRevenueOverTimeDetails</Role>
      <ShortName>Revenue Recognition (Revenue Over Time) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/RevenueRecognitionTableTextBlock</ParentRole>
      <Position>127</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R128.htm</HtmlFileName>
      <LongName>996625 - Disclosure - Revenue Recognition (Revenue disaggregated by timing of revenue recognition) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/RevenueRecognitionRevenueDisaggregatedByTimingOfRevenueRecognitionDetails</Role>
      <ShortName>Revenue Recognition (Revenue disaggregated by timing of revenue recognition) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/RevenueRecognitionTableTextBlock</ParentRole>
      <Position>128</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R129.htm</HtmlFileName>
      <LongName>996635 - Disclosure - Allowance for Credit Losses (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/AllowanceForCreditLossesNarratives</Role>
      <ShortName>Allowance for Credit Losses (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/AllowanceForCreditLossesTableTextBlock</ParentRole>
      <Position>129</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R130.htm</HtmlFileName>
      <LongName>996645 - Disclosure - Allowance for Credit Losses (Reserve Allowance Various Credit Loss) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/AllowanceForCreditLossesReserveAllowanceVariousCreditLossDetails</Role>
      <ShortName>Allowance for Credit Losses (Reserve Allowance Various Credit Loss) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/AllowanceForCreditLossesTableTextBlock</ParentRole>
      <Position>130</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R131.htm</HtmlFileName>
      <LongName>996655 - Disclosure - Reinsurance and Policy Benefits and Losses, Claims and Loss Expenses Payable - (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureReinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensesPayableNarrativesDetails</Role>
      <ShortName>Reinsurance and Policy Benefits and Losses, Claims and Loss Expenses Payable - (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/reinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensesPayableTableTextBlock</ParentRole>
      <Position>131</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R132.htm</HtmlFileName>
      <LongName>996665 - Disclosure - Reinsurance and Policy Benefits and Losses, Claims and Loss Expenses Payable (Insurance Subsidiaries Activity) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/ReinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensesPayableInsuranceSubsidiariesActivityDetails</Role>
      <ShortName>Reinsurance and Policy Benefits and Losses, Claims and Loss Expenses Payable (Insurance Subsidiaries Activity) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/reinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensesPayableTableTextBlock</ParentRole>
      <Position>132</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R133.htm</HtmlFileName>
      <LongName>996675 - Disclosure - Reinsurance and Policy Benefits and Losses Claims and Loss Expenses Payable (Policy Benefits and Losses, Claims and Loss Expenses Payable for Property and Casualty Insurance) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/ReinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensesPayablePropertyAndCasualtyInsuranceDetails</Role>
      <ShortName>Reinsurance and Policy Benefits and Losses Claims and Loss Expenses Payable (Policy Benefits and Losses, Claims and Loss Expenses Payable for Property and Casualty Insurance) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>133</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R134.htm</HtmlFileName>
      <LongName>996685 - Disclosure - Reinsurance and Policy Benefits and Losses, Claims and Loss Expenses Payable (Activity in the Liability for Unpaid Losses and Loss Adjustment Expenses for Property and Casualty Insurance) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureReinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensesPayableActivityInTheLiabilityForUnpaidLossesAndLossAdjustmentExpenses</Role>
      <ShortName>Reinsurance and Policy Benefits and Losses, Claims and Loss Expenses Payable (Activity in the Liability for Unpaid Losses and Loss Adjustment Expenses for Property and Casualty Insurance) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/reinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensesPayableTableTextBlock</ParentRole>
      <Position>134</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R135.htm</HtmlFileName>
      <LongName>996695 - Disclosure - Reinsurance and Policy Benefits and Losses, Claims, and Loss Expenses Payable (Incurred Claims Development) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/ReinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensesPayableIncurredClaimsDevelopmentDetails</Role>
      <ShortName>Reinsurance and Policy Benefits and Losses, Claims, and Loss Expenses Payable (Incurred Claims Development) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>135</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R136.htm</HtmlFileName>
      <LongName>996705 - Disclosure - Reinsurance And Policy Benefits And Losses Claims And Loss Expenses Payable (Cumulative Paid Claims And Allocated Claim Adjustment Expense Net Of Reinsurance) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/ReinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensesPayableCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNetOfReinsuranceDetails</Role>
      <ShortName>Reinsurance And Policy Benefits And Losses Claims And Loss Expenses Payable (Cumulative Paid Claims And Allocated Claim Adjustment Expense Net Of Reinsurance) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>136</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R137.htm</HtmlFileName>
      <LongName>996715 - Disclosure - Reinsurance And Policy Benefits And Losses Claims And Loss Expenses Payable (Total Gross Liability For Unpaid Property And Casualty Claims And Claim Adjustment Expense) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/ReinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensesPayableTotalGrossLiabilityForUnpaidPropertyAndCasualtyClaimsAndClaimAdjustmentExpenseDetails</Role>
      <ShortName>Reinsurance And Policy Benefits And Losses Claims And Loss Expenses Payable (Total Gross Liability For Unpaid Property And Casualty Claims And Claim Adjustment Expense) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>137</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R138.htm</HtmlFileName>
      <LongName>996725 - Disclosure - Reinsurance And Policy Benefits And Losses Claims And Loss Expenses Payable (Average Annual Percentage Payout Of Incurred Claims By Age Net Of Reinsurance) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/ReinsuranceAndPolicyBenefitsAndLossesClaimsAndLossExpensesPayableAverageAnnualPercentagePayoutOfIncurredClaimsByAgeNetOfReinsuranceDetails</Role>
      <ShortName>Reinsurance And Policy Benefits And Losses Claims And Loss Expenses Payable (Average Annual Percentage Payout Of Incurred Claims By Age Net Of Reinsurance) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>138</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R139.htm</HtmlFileName>
      <LongName>996735 - Disclosure - Deferred Policy Acquisition Costs, Net (Schedule of Deferred Policy Acquisition Costs (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureDeferredPolicyAcquisitionCostsNetScheduleOfDeferredPolicyAcquisitionCostsDetails</Role>
      <ShortName>Deferred Policy Acquisition Costs, Net (Schedule of Deferred Policy Acquisition Costs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureDeferredPolicyAcquisitionCostsNetTableTextBlock</ParentRole>
      <Position>139</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R140.htm</HtmlFileName>
      <LongName>996745 - Disclosure - Life Insurance Liabilities (Present Value Expected Net Premiums) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureLifeInsuranceLiabilitiesPresentValueExpectedNetPremiumsDetails</Role>
      <ShortName>Life Insurance Liabilities (Present Value Expected Net Premiums) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureLifeInsuranceLiabilitiesTableTextBlock</ParentRole>
      <Position>140</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R141.htm</HtmlFileName>
      <LongName>996755 - Disclosure - Life Insurance Liabilities (Present Value Expected Future Policy Benefits) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureLifeInsuranceLiabilitiesPresentValueExpectedFuturePolicyBenefitsDetails</Role>
      <ShortName>Life Insurance Liabilities (Present Value Expected Future Policy Benefits) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureLifeInsuranceLiabilitiesTableTextBlock</ParentRole>
      <Position>141</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R142.htm</HtmlFileName>
      <LongName>996765 - Disclosure - Life Insurance Liabilities (Sensitive Life Insurance Type Products) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureLifeInsuranceLiabilitiesSensitiveLifeInsuranceTypeProductsDetails</Role>
      <ShortName>Life Insurance Liabilities (Sensitive Life Insurance Type Products) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureLifeInsuranceLiabilitiesTableTextBlock</ParentRole>
      <Position>142</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R143.htm</HtmlFileName>
      <LongName>996775 - Disclosure - Life Insurance Liabilities - (Balance Changes Liabilities Investment Contracts) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/DisclosureLifeInsuranceLiabilitiesBalanceChangesLiabilitiesInvestmentContractsDetails</Role>
      <ShortName>Life Insurance Liabilities - (Balance Changes Liabilities Investment Contracts) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/DisclosureLifeInsuranceLiabilitiesTableTextBlock</ParentRole>
      <Position>143</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R144.htm</HtmlFileName>
      <LongName>996785 - Disclosure - Statutory Financial Information of Insurance Subsidiaries (Narratives) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/StatutoryFinancialInformationOfInsuranceSubsidiariesNarrativesDetals</Role>
      <ShortName>Statutory Financial Information of Insurance Subsidiaries (Narratives) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/statutoryFinancialInformationOfInsuranceSubsidiariesTableTextBlock</ParentRole>
      <Position>144</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R145.htm</HtmlFileName>
      <LongName>996795 - Disclosure - Statutory Financial Information of Insurance Subsidiaries (Net income (loss) Capital and Surplus (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/StatutoryFinancialInformationOfInsuranceSubsidiariesNetIncomeLossCapitalAndSurplusDetails</Role>
      <ShortName>Statutory Financial Information of Insurance Subsidiaries (Net income (loss) Capital and Surplus (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://amerco.com/20260331/taxonomy/role/statutoryFinancialInformationOfInsuranceSubsidiariesTableTextBlock</ParentRole>
      <Position>145</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R146.htm</HtmlFileName>
      <LongName>996805 - Disclosure - Schedule II - U-Haul Holding Company and Consolidated Subsidiaries, Valuation and Qualifying Accounts (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/ScheduleIIUHaulHoldingCompanyAndConsolidatedSubsidiariesValuationAndQualifyingAccountsDetails</Role>
      <ShortName>Schedule II - U-Haul Holding Company and Consolidated Subsidiaries, Valuation and Qualifying Accounts (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>146</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R147.htm</HtmlFileName>
      <LongName>996815 - Disclosure - Schedule V - U-Haul Holding Company and Consolidated Subsidiaries, Supplemental Information (for Property-Casualty Insurance Operations) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/ScheduleVUHaulHoldingCompanyAndConsolidatedSubsidiariesSupplementalInformationForPropertyCasualtyInsuranceOperationsDetails</Role>
      <ShortName>Schedule V - U-Haul Holding Company and Consolidated Subsidiaries, Supplemental Information (for Property-Casualty Insurance Operations) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>147</Position>
    </Report>
    <Report instance="uhal-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R148.htm</HtmlFileName>
      <LongName>996825 - Disclosure - Schedule V - U-Haul Holding Company and Consolidated Subsidiaries, Supplemental Information (for Property-Casualty Insurance Operations), Parenthetical (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://amerco.com/20260331/taxonomy/role/ScheduleVUHaulHoldingCompanyAndConsolidatedSubsidiariesSupplementalInformationForPropertyCasualtyInsuranceOperationsParentheticalDetails</Role>
      <ShortName>Schedule V - U-Haul Holding Company and Consolidated Subsidiaries, Supplemental Information (for Property-Casualty Insurance Operations), Parenthetical (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>148</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-K" isDefinitelyFs="true" isUsgaap="true" original="uhal-20260331.htm">uhal-20260331.htm</File>
    <File>uhal-20260331.xsd</File>
  </InputFiles>
  <SupplementalFiles>
    <File>img165855109_0.jpg</File>
    <File>img165855109_1.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="24">http://fasb.org/srt/2025</BaseTaxonomy>
    <BaseTaxonomy items="2180">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="6">http://xbrl.sec.gov/cyd/2025</BaseTaxonomy>
    <BaseTaxonomy items="42">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>false</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
