<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.21.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>1087</ContextCount>
  <ElementCount>723</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>305</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>10</UnitCount>
  <MyReports>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000010001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>100010002 - Statement - Consolidated (Loss) Income Statement</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ConsolidatedLossIncomeStatement</Role>
      <ShortName>Consolidated (Loss) Income Statement</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>100020003 - Statement - Consolidated Statement of Comprehensive (Loss) Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ConsolidatedStatementofComprehensiveLossIncome</Role>
      <ShortName>Consolidated Statement of Comprehensive (Loss) Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>100030004 - Statement - Consolidated Statement of Financial Position</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ConsolidatedStatementofFinancialPosition</Role>
      <ShortName>Consolidated Statement of Financial Position</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>100040005 - Statement - Consolidated Statement of Changes in Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ConsolidatedStatementofChangesinEquity</Role>
      <ShortName>Consolidated Statement of Changes in Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>100050006 - Statement - Consolidated Statement of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ConsolidatedStatementofCashFlows</Role>
      <ShortName>Consolidated Statement of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>210011001 - Disclosure - NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/NATUREOFOPERATIONSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES</Role>
      <ShortName>NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>210051002 - Disclosure - CHANGES IN ACCOUNTING POLICIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/CHANGESINACCOUNTINGPOLICIES</Role>
      <ShortName>CHANGES IN ACCOUNTING POLICIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>210061003 - Disclosure - IMPACT OF THE COVID-19 PANDEMIC</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/IMPACTOFTHECOVID19PANDEMIC</Role>
      <ShortName>IMPACT OF THE COVID-19 PANDEMIC</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>210071004 - Disclosure - BUSINESS COMBINATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/BUSINESSCOMBINATIONS</Role>
      <ShortName>BUSINESS COMBINATIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>210111005 - Disclosure - L3HARRIS' MILITARY TRAINING BUSINESS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/L3HARRISMILITARYTRAININGBUSINESS</Role>
      <ShortName>L3HARRIS' MILITARY TRAINING BUSINESS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>210151006 - Disclosure - OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OPERATINGSEGMENTSANDGEOGRAPHICINFORMATION</Role>
      <ShortName>OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>210241007 - Disclosure - OTHER (GAINS) AND LOSSES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OTHERGAINSANDLOSSES</Role>
      <ShortName>OTHER (GAINS) AND LOSSES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>210281008 - Disclosure - RESTRUCTURING, INTEGRATION AND ACQUISITION COSTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/RESTRUCTURINGINTEGRATIONANDACQUISITIONCOSTS</Role>
      <ShortName>RESTRUCTURING, INTEGRATION AND ACQUISITION COSTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>210321009 - Disclosure - FINANCE EXPENSE - NET</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FINANCEEXPENSENET</Role>
      <ShortName>FINANCE EXPENSE - NET</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>210351010 - Disclosure - INCOME TAXES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INCOMETAXES</Role>
      <ShortName>INCOME TAXES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>210421011 - Disclosure - SHARE CAPITAL, EARNINGS PER SHARE AND DIVIDENDS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SHARECAPITALEARNINGSPERSHAREANDDIVIDENDS</Role>
      <ShortName>SHARE CAPITAL, EARNINGS PER SHARE AND DIVIDENDS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>210461012 - Disclosure - ACCOUNTS RECEIVABLE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ACCOUNTSRECEIVABLE</Role>
      <ShortName>ACCOUNTS RECEIVABLE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>210491013 - Disclosure - BALANCE FROM CONTRACTS WITH CUSTOMERS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/BALANCEFROMCONTRACTSWITHCUSTOMERS</Role>
      <ShortName>BALANCE FROM CONTRACTS WITH CUSTOMERS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>210531014 - Disclosure - INVENTORIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INVENTORIES</Role>
      <ShortName>INVENTORIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>210571015 - Disclosure - PROPERTY, PLANT AND EQUIPMENT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/PROPERTYPLANTANDEQUIPMENT</Role>
      <ShortName>PROPERTY, PLANT AND EQUIPMENT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>210611016 - Disclosure - INTANGIBLE ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INTANGIBLEASSETS</Role>
      <ShortName>INTANGIBLE ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>210641017 - Disclosure - LEASES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/LEASES</Role>
      <ShortName>LEASES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>210701018 - Disclosure - OTHER NON-CURRENT ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OTHERNONCURRENTASSETS</Role>
      <ShortName>OTHER NON-CURRENT ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>210731019 - Disclosure - ACCOUNTS PAYABLE AND ACCRUED LIABILITIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ACCOUNTSPAYABLEANDACCRUEDLIABILITIES</Role>
      <ShortName>ACCOUNTS PAYABLE AND ACCRUED LIABILITIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>210761020 - Disclosure - PROVISIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/PROVISIONS</Role>
      <ShortName>PROVISIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>210791021 - Disclosure - DEBT FACILITIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/DEBTFACILITIES</Role>
      <ShortName>DEBT FACILITIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>210841022 - Disclosure - EMPLOYEE BENEFITS OBLIGATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEEBENEFITSOBLIGATIONS</Role>
      <ShortName>EMPLOYEE BENEFITS OBLIGATIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>210951023 - Disclosure - OTHER NON-CURRENT LIABILITIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OTHERNONCURRENTLIABILITIES</Role>
      <ShortName>OTHER NON-CURRENT LIABILITIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>210981024 - Disclosure - SUPPLEMENTARY CASH FLOWS INFORMATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SUPPLEMENTARYCASHFLOWSINFORMATION</Role>
      <ShortName>SUPPLEMENTARY CASH FLOWS INFORMATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>211011025 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE INCOME</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ACCUMULATEDOTHERCOMPREHENSIVEINCOME</Role>
      <ShortName>ACCUMULATED OTHER COMPREHENSIVE INCOME</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>211041026 - Disclosure - SHARE-BASED PAYMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SHAREBASEDPAYMENTS</Role>
      <ShortName>SHARE-BASED PAYMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>211131027 - Disclosure - EMPLOYEE COMPENSATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEECOMPENSATION</Role>
      <ShortName>EMPLOYEE COMPENSATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>211161028 - Disclosure - GOVERNMENT PARTICIPATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/GOVERNMENTPARTICIPATION</Role>
      <ShortName>GOVERNMENT PARTICIPATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>211191029 - Disclosure - IMPAIRMENT OF NON-FINANCIAL ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/IMPAIRMENTOFNONFINANCIALASSETS</Role>
      <ShortName>IMPAIRMENT OF NON-FINANCIAL ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>211231030 - Disclosure - CONTINGENCIES AND COMMITMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/CONTINGENCIESANDCOMMITMENTS</Role>
      <ShortName>CONTINGENCIES AND COMMITMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>211261031 - Disclosure - FAIR VALUE OF FINANCIAL INSTRUMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FAIRVALUEOFFINANCIALINSTRUMENTS</Role>
      <ShortName>FAIR VALUE OF FINANCIAL INSTRUMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>211291032 - Disclosure - CAPITAL RISK MANAGEMENT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/CAPITALRISKMANAGEMENT</Role>
      <ShortName>CAPITAL RISK MANAGEMENT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>211321033 - Disclosure - FINANCIAL RISK MANAGEMENT</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FINANCIALRISKMANAGEMENT</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>211401034 - Disclosure - RELATED PARTY RELATIONSHIPS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/RELATEDPARTYRELATIONSHIPS</Role>
      <ShortName>RELATED PARTY RELATIONSHIPS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>211431035 - Disclosure - RELATED PARTY TRANSACTIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/RELATEDPARTYTRANSACTIONS</Role>
      <ShortName>RELATED PARTY TRANSACTIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>220022001 - Disclosure - NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/NATUREOFOPERATIONSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies</Role>
      <ShortName>NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>230033001 - Disclosure - NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/NATUREOFOPERATIONSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESTables</Role>
      <ShortName>NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/NATUREOFOPERATIONSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>230083002 - Disclosure - BUSINESS COMBINATIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/BUSINESSCOMBINATIONSTables</Role>
      <ShortName>BUSINESS COMBINATIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/BUSINESSCOMBINATIONS</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>230123003 - Disclosure - L3HARRIS' MILITARY TRAINING BUSINESS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/L3HARRISMILITARYTRAININGBUSINESSTables</Role>
      <ShortName>L3HARRIS' MILITARY TRAINING BUSINESS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/L3HARRISMILITARYTRAININGBUSINESS</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>230163004 - Disclosure - OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OPERATINGSEGMENTSANDGEOGRAPHICINFORMATIONTables</Role>
      <ShortName>OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/OPERATINGSEGMENTSANDGEOGRAPHICINFORMATION</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>230253005 - Disclosure - OTHER (GAINS) AND LOSSES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OTHERGAINSANDLOSSESTables</Role>
      <ShortName>OTHER (GAINS) AND LOSSES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/OTHERGAINSANDLOSSES</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>230293006 - Disclosure - RESTRUCTURING, INTEGRATION AND ACQUISITION COSTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/RESTRUCTURINGINTEGRATIONANDACQUISITIONCOSTSTables</Role>
      <ShortName>RESTRUCTURING, INTEGRATION AND ACQUISITION COSTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/RESTRUCTURINGINTEGRATIONANDACQUISITIONCOSTS</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>230333007 - Disclosure - FINANCE EXPENSE - NET (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FINANCEEXPENSENETTables</Role>
      <ShortName>FINANCE EXPENSE - NET (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/FINANCEEXPENSENET</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>230363008 - Disclosure - INCOME TAXES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INCOMETAXESTables</Role>
      <ShortName>INCOME TAXES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/INCOMETAXES</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>230433009 - Disclosure - SHARE CAPITAL, EARNINGS PER SHARE AND DIVIDENDS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SHARECAPITALEARNINGSPERSHAREANDDIVIDENDSTables</Role>
      <ShortName>SHARE CAPITAL, EARNINGS PER SHARE AND DIVIDENDS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/SHARECAPITALEARNINGSPERSHAREANDDIVIDENDS</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>230473010 - Disclosure - ACCOUNTS RECEIVABLE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ACCOUNTSRECEIVABLETables</Role>
      <ShortName>ACCOUNTS RECEIVABLE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/ACCOUNTSRECEIVABLE</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>230503011 - Disclosure - BALANCE FROM CONTRACTS WITH CUSTOMERS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/BALANCEFROMCONTRACTSWITHCUSTOMERSTables</Role>
      <ShortName>BALANCE FROM CONTRACTS WITH CUSTOMERS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/BALANCEFROMCONTRACTSWITHCUSTOMERS</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>230543012 - Disclosure - INVENTORIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INVENTORIESTables</Role>
      <ShortName>INVENTORIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/INVENTORIES</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>230583013 - Disclosure - PROPERTY, PLANT AND EQUIPMENT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/PROPERTYPLANTANDEQUIPMENTTables</Role>
      <ShortName>PROPERTY, PLANT AND EQUIPMENT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/PROPERTYPLANTANDEQUIPMENT</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>230623014 - Disclosure - INTANGIBLE ASSETS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INTANGIBLEASSETSTables</Role>
      <ShortName>INTANGIBLE ASSETS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/INTANGIBLEASSETS</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>230653015 - Disclosure - LEASES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/LEASESTables</Role>
      <ShortName>LEASES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/LEASES</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>230713016 - Disclosure - OTHER NON-CURRENT ASSETS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OTHERNONCURRENTASSETSTables</Role>
      <ShortName>OTHER NON-CURRENT ASSETS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/OTHERNONCURRENTASSETS</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>230743017 - Disclosure - ACCOUNTS PAYABLE AND ACCRUED LIABILITIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ACCOUNTSPAYABLEANDACCRUEDLIABILITIESTables</Role>
      <ShortName>ACCOUNTS PAYABLE AND ACCRUED LIABILITIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/ACCOUNTSPAYABLEANDACCRUEDLIABILITIES</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>230773018 - Disclosure - PROVISIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/PROVISIONSTables</Role>
      <ShortName>PROVISIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/PROVISIONS</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>230803019 - Disclosure - DEBT FACILITIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/DEBTFACILITIESTables</Role>
      <ShortName>DEBT FACILITIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/DEBTFACILITIES</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>230853020 - Disclosure - EMPLOYEE BENEFITS OBLIGATIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEEBENEFITSOBLIGATIONSTables</Role>
      <ShortName>EMPLOYEE BENEFITS OBLIGATIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/EMPLOYEEBENEFITSOBLIGATIONS</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>230963021 - Disclosure - OTHER NON-CURRENT LIABILITIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OTHERNONCURRENTLIABILITIESTables</Role>
      <ShortName>OTHER NON-CURRENT LIABILITIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/OTHERNONCURRENTLIABILITIES</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>230993022 - Disclosure - SUPPLEMENTARY CASH FLOWS INFORMATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SUPPLEMENTARYCASHFLOWSINFORMATIONTables</Role>
      <ShortName>SUPPLEMENTARY CASH FLOWS INFORMATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/SUPPLEMENTARYCASHFLOWSINFORMATION</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>231023023 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE INCOME (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ACCUMULATEDOTHERCOMPREHENSIVEINCOMETables</Role>
      <ShortName>ACCUMULATED OTHER COMPREHENSIVE INCOME (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/ACCUMULATEDOTHERCOMPREHENSIVEINCOME</ParentRole>
      <Position>65</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>231053024 - Disclosure - SHARE-BASED PAYMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SHAREBASEDPAYMENTSTables</Role>
      <ShortName>SHARE-BASED PAYMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/SHAREBASEDPAYMENTS</ParentRole>
      <Position>66</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>231143025 - Disclosure - EMPLOYEE COMPENSATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEECOMPENSATIONTables</Role>
      <ShortName>EMPLOYEE COMPENSATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/EMPLOYEECOMPENSATION</ParentRole>
      <Position>67</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>231173026 - Disclosure - GOVERNMENT PARTICIPATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/GOVERNMENTPARTICIPATIONTables</Role>
      <ShortName>GOVERNMENT PARTICIPATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/GOVERNMENTPARTICIPATION</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>231203027 - Disclosure - IMPAIRMENT OF NON-FINANCIAL ASSETS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/IMPAIRMENTOFNONFINANCIALASSETSTables</Role>
      <ShortName>IMPAIRMENT OF NON-FINANCIAL ASSETS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/IMPAIRMENTOFNONFINANCIALASSETS</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>231243028 - Disclosure - CONTINGENCIES AND COMMITMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/CONTINGENCIESANDCOMMITMENTSTables</Role>
      <ShortName>CONTINGENCIES AND COMMITMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/CONTINGENCIESANDCOMMITMENTS</ParentRole>
      <Position>70</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>231273029 - Disclosure - FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSTables</Role>
      <ShortName>FAIR VALUE OF FINANCIAL INSTRUMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/FAIRVALUEOFFINANCIALINSTRUMENTS</ParentRole>
      <Position>71</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>231303030 - Disclosure - CAPITAL RISK MANAGEMENT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/CAPITALRISKMANAGEMENTTables</Role>
      <ShortName>CAPITAL RISK MANAGEMENT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/CAPITALRISKMANAGEMENT</ParentRole>
      <Position>72</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>231333031 - Disclosure - FINANCIAL RISK MANAGEMENT (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FINANCIALRISKMANAGEMENTTables</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/FINANCIALRISKMANAGEMENT</ParentRole>
      <Position>73</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>231413032 - Disclosure - RELATED PARTY RELATIONSHIPS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/RELATEDPARTYRELATIONSHIPSTables</Role>
      <ShortName>RELATED PARTY RELATIONSHIPS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/RELATEDPARTYRELATIONSHIPS</ParentRole>
      <Position>74</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>231443033 - Disclosure - RELATED PARTY TRANSACTIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/RELATEDPARTYTRANSACTIONSTables</Role>
      <ShortName>RELATED PARTY TRANSACTIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.cae.com/role/RELATEDPARTYTRANSACTIONS</ParentRole>
      <Position>75</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>240044001 - Disclosure - NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/NATUREOFOPERATIONSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESDetails</Role>
      <ShortName>NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/NATUREOFOPERATIONSANDSUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESTables</ParentRole>
      <Position>76</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>240094002 - Disclosure - BUSINESS COMBINATIONS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/BUSINESSCOMBINATIONSNarrativeDetails</Role>
      <ShortName>BUSINESS COMBINATIONS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>240104003 - Disclosure - BUSINESS COMBINATIONS - Net Assets and Liabilities from Acquisition (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/BUSINESSCOMBINATIONSNetAssetsandLiabilitiesfromAcquisitionDetails</Role>
      <ShortName>BUSINESS COMBINATIONS - Net Assets and Liabilities from Acquisition (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>240134004 - Disclosure - L3HARRIS' MILITARY TRAINING BUSINESS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/L3HARRISMILITARYTRAININGBUSINESSNarrativeDetails</Role>
      <ShortName>L3HARRIS' MILITARY TRAINING BUSINESS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>240144005 - Disclosure - L3HARRIS' MILITARY TRAINING BUSINESS - Private placements of subscription receipts (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/L3HARRISMILITARYTRAININGBUSINESSPrivateplacementsofsubscriptionreceiptsDetails</Role>
      <ShortName>L3HARRIS' MILITARY TRAINING BUSINESS - Private placements of subscription receipts (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>240174006 - Disclosure - OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OPERATINGSEGMENTSANDGEOGRAPHICINFORMATIONNarrativeDetails</Role>
      <ShortName>OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>81</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>240184007 - Disclosure - OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Results by segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OPERATINGSEGMENTSANDGEOGRAPHICINFORMATIONResultsbysegmentDetails</Role>
      <ShortName>OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Results by segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>240194008 - Disclosure - OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Reconciliation of adjusted segment operating income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OPERATINGSEGMENTSANDGEOGRAPHICINFORMATIONReconciliationofadjustedsegmentoperatingincomeDetails</Role>
      <ShortName>OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Reconciliation of adjusted segment operating income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>83</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>240204009 - Disclosure - OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Capital Expenditures (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OPERATINGSEGMENTSANDGEOGRAPHICINFORMATIONCapitalExpendituresDetails</Role>
      <ShortName>OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Capital Expenditures (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>84</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>240214010 - Disclosure - OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Assets And Liabilities Employed By Segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OPERATINGSEGMENTSANDGEOGRAPHICINFORMATIONAssetsAndLiabilitiesEmployedBySegmentDetails</Role>
      <ShortName>OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Assets And Liabilities Employed By Segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>85</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>240224011 - Disclosure - OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Products and Services Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OPERATINGSEGMENTSANDGEOGRAPHICINFORMATIONProductsandServicesInformationDetails</Role>
      <ShortName>OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Products and Services Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>86</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>240234012 - Disclosure - OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Geographic information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OPERATINGSEGMENTSANDGEOGRAPHICINFORMATIONGeographicinformationDetails</Role>
      <ShortName>OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION - Geographic information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>87</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>240264013 - Disclosure - OTHER (GAINS) AND LOSSES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OTHERGAINSANDLOSSESDetails</Role>
      <ShortName>OTHER (GAINS) AND LOSSES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/OTHERGAINSANDLOSSESTables</ParentRole>
      <Position>88</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>240274014 - Disclosure - OTHER (GAINS) AND LOSSES - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OTHERGAINSANDLOSSESNarrativeDetails</Role>
      <ShortName>OTHER (GAINS) AND LOSSES - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/OTHERGAINSANDLOSSESTables</ParentRole>
      <Position>89</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>240304015 - Disclosure - RESTRUCTURING, INTEGRATION AND ACQUISITION COSTS - Analysis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/RESTRUCTURINGINTEGRATIONANDACQUISITIONCOSTSAnalysisDetails</Role>
      <ShortName>RESTRUCTURING, INTEGRATION AND ACQUISITION COSTS - Analysis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/RESTRUCTURINGINTEGRATIONANDACQUISITIONCOSTSTables</ParentRole>
      <Position>90</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>240314016 - Disclosure - RESTRUCTURING, INTEGRATION AND ACQUISITION COSTS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/RESTRUCTURINGINTEGRATIONANDACQUISITIONCOSTSNarrativeDetails</Role>
      <ShortName>RESTRUCTURING, INTEGRATION AND ACQUISITION COSTS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/RESTRUCTURINGINTEGRATIONANDACQUISITIONCOSTSTables</ParentRole>
      <Position>91</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>240344017 - Disclosure - FINANCE EXPENSE - NET (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FINANCEEXPENSENETDetails</Role>
      <ShortName>FINANCE EXPENSE - NET (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/FINANCEEXPENSENETTables</ParentRole>
      <Position>92</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>240374018 - Disclosure - INCOME TAXES - Reconciliation of Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INCOMETAXESReconciliationofIncomeTaxesDetails</Role>
      <ShortName>INCOME TAXES - Reconciliation of Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>93</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>240384019 - Disclosure - INCOME TAXES - Components of the Provision for the Income Tax Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INCOMETAXESComponentsoftheProvisionfortheIncomeTaxExpenseDetails</Role>
      <ShortName>INCOME TAXES - Components of the Provision for the Income Tax Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>94</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>240394020 - Disclosure - INCOME TAXES - Movements In Temporary Differences (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INCOMETAXESMovementsInTemporaryDifferencesDetails</Role>
      <ShortName>INCOME TAXES - Movements In Temporary Differences (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>95</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>240404021 - Disclosure - INCOME TAXES - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INCOMETAXESNarrativeDetails</Role>
      <ShortName>INCOME TAXES - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>96</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>240414022 - Disclosure - INCOME TAXES - Non-capital Losses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INCOMETAXESNoncapitalLossesDetails</Role>
      <ShortName>INCOME TAXES - Non-capital Losses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>97</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R98.htm</HtmlFileName>
      <LongName>240444023 - Disclosure - SHARE CAPITAL, EARNINGS PER SHARE AND DIVIDENDS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SHARECAPITALEARNINGSPERSHAREANDDIVIDENDSNarrativeDetails</Role>
      <ShortName>SHARE CAPITAL, EARNINGS PER SHARE AND DIVIDENDS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>98</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R99.htm</HtmlFileName>
      <LongName>240454024 - Disclosure - SHARE CAPITAL, EARNINGS PER SHARE AND DIVIDENDS - Earnings per share computation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SHARECAPITALEARNINGSPERSHAREANDDIVIDENDSEarningspersharecomputationDetails</Role>
      <ShortName>SHARE CAPITAL, EARNINGS PER SHARE AND DIVIDENDS - Earnings per share computation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>99</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R100.htm</HtmlFileName>
      <LongName>240484025 - Disclosure - ACCOUNTS RECEIVABLE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ACCOUNTSRECEIVABLEDetails</Role>
      <ShortName>ACCOUNTS RECEIVABLE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/ACCOUNTSRECEIVABLETables</ParentRole>
      <Position>100</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R101.htm</HtmlFileName>
      <LongName>240514026 - Disclosure - BALANCE FROM CONTRACTS WITH CUSTOMERS - Net Contract Assets (Liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/BALANCEFROMCONTRACTSWITHCUSTOMERSNetContractAssetsLiabilitiesDetails</Role>
      <ShortName>BALANCE FROM CONTRACTS WITH CUSTOMERS - Net Contract Assets (Liabilities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>101</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R102.htm</HtmlFileName>
      <LongName>240524027 - Disclosure - BALANCE FROM CONTRACTS WITH CUSTOMERS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/BALANCEFROMCONTRACTSWITHCUSTOMERSNarrativeDetails</Role>
      <ShortName>BALANCE FROM CONTRACTS WITH CUSTOMERS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>102</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R103.htm</HtmlFileName>
      <LongName>240554028 - Disclosure - INVENTORIES - Summary of Inventories (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INVENTORIESSummaryofInventoriesDetails</Role>
      <ShortName>INVENTORIES - Summary of Inventories (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>103</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R104.htm</HtmlFileName>
      <LongName>240564029 - Disclosure - INVENTORIES - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INVENTORIESNarrativeDetails</Role>
      <ShortName>INVENTORIES - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>104</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R105.htm</HtmlFileName>
      <LongName>240594030 - Disclosure - PROPERTY, PLANT AND EQUIPMENT - Summaries of Property, Plant and Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/PROPERTYPLANTANDEQUIPMENTSummariesofPropertyPlantandEquipmentDetails</Role>
      <ShortName>PROPERTY, PLANT AND EQUIPMENT - Summaries of Property, Plant and Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>105</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R106.htm</HtmlFileName>
      <LongName>240604031 - Disclosure - PROPERTY, PLANT AND EQUIPMENT - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/PROPERTYPLANTANDEQUIPMENTNarrativeDetails</Role>
      <ShortName>PROPERTY, PLANT AND EQUIPMENT - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>106</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R107.htm</HtmlFileName>
      <LongName>240634032 - Disclosure - INTANGIBLE ASSETS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/INTANGIBLEASSETSDetails</Role>
      <ShortName>INTANGIBLE ASSETS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/INTANGIBLEASSETSTables</ParentRole>
      <Position>107</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R108.htm</HtmlFileName>
      <LongName>240664033 - Disclosure - LEASES - Schedule of Right-Of-Use Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/LEASESScheduleofRightOfUseAssetsDetails</Role>
      <ShortName>LEASES - Schedule of Right-Of-Use Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>108</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R109.htm</HtmlFileName>
      <LongName>240674034 - Disclosure - LEASES - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/LEASESNarrativeDetails</Role>
      <ShortName>LEASES - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>109</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R110.htm</HtmlFileName>
      <LongName>240684035 - Disclosure - LEASES - Schedule of Undiscounted Lease Payments to be Received Under Operating Leases (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/LEASESScheduleofUndiscountedLeasePaymentstobeReceivedUnderOperatingLeasesDetails</Role>
      <ShortName>LEASES - Schedule of Undiscounted Lease Payments to be Received Under Operating Leases (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>110</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R111.htm</HtmlFileName>
      <LongName>240694036 - Disclosure - LEASES - Schedule of Undiscounted Lease Payments to be Received Under Finance Leases (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/LEASESScheduleofUndiscountedLeasePaymentstobeReceivedUnderFinanceLeasesDetails</Role>
      <ShortName>LEASES - Schedule of Undiscounted Lease Payments to be Received Under Finance Leases (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>111</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R112.htm</HtmlFileName>
      <LongName>240724037 - Disclosure - OTHER NON-CURRENT ASSETS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OTHERNONCURRENTASSETSDetails</Role>
      <ShortName>OTHER NON-CURRENT ASSETS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/OTHERNONCURRENTASSETSTables</ParentRole>
      <Position>112</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R113.htm</HtmlFileName>
      <LongName>240754038 - Disclosure - ACCOUNTS PAYABLE AND ACCRUED LIABILITIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ACCOUNTSPAYABLEANDACCRUEDLIABILITIESDetails</Role>
      <ShortName>ACCOUNTS PAYABLE AND ACCRUED LIABILITIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/ACCOUNTSPAYABLEANDACCRUEDLIABILITIESTables</ParentRole>
      <Position>113</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R114.htm</HtmlFileName>
      <LongName>240784039 - Disclosure - PROVISIONS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/PROVISIONSDetails</Role>
      <ShortName>PROVISIONS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/PROVISIONSTables</ParentRole>
      <Position>114</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R115.htm</HtmlFileName>
      <LongName>240814040 - Disclosure - DEBT FACILITIES - Long-term Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/DEBTFACILITIESLongtermDebtDetails</Role>
      <ShortName>DEBT FACILITIES - Long-term Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>115</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R116.htm</HtmlFileName>
      <LongName>240824041 - Disclosure - DEBT FACILITIES - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/DEBTFACILITIESNarrativeDetails</Role>
      <ShortName>DEBT FACILITIES - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>116</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R117.htm</HtmlFileName>
      <LongName>240834042 - Disclosure - DEBT FACILITIES - Financing Activities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/DEBTFACILITIESFinancingActivitiesDetails</Role>
      <ShortName>DEBT FACILITIES - Financing Activities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>117</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R118.htm</HtmlFileName>
      <LongName>240864043 - Disclosure - EMPLOYEE BENEFITS OBLIGATIONS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEEBENEFITSOBLIGATIONSNarrativeDetails</Role>
      <ShortName>EMPLOYEE BENEFITS OBLIGATIONS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>118</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R119.htm</HtmlFileName>
      <LongName>240874044 - Disclosure - EMPLOYEE BENEFITS OBLIGATIONS - Employee Benefit Obligation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEEBENEFITSOBLIGATIONSEmployeeBenefitObligationDetails</Role>
      <ShortName>EMPLOYEE BENEFITS OBLIGATIONS - Employee Benefit Obligation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>119</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R120.htm</HtmlFileName>
      <LongName>240884045 - Disclosure - EMPLOYEE BENEFITS OBLIGATIONS - Movement In Defined Benefit Pension Obligation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEEBENEFITSOBLIGATIONSMovementInDefinedBenefitPensionObligationDetails</Role>
      <ShortName>EMPLOYEE BENEFITS OBLIGATIONS - Movement In Defined Benefit Pension Obligation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>120</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R121.htm</HtmlFileName>
      <LongName>240894046 - Disclosure - EMPLOYEE BENEFITS OBLIGATIONS - Net Periodic Costs (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEEBENEFITSOBLIGATIONSNetPeriodicCostsDetails</Role>
      <ShortName>EMPLOYEE BENEFITS OBLIGATIONS - Net Periodic Costs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>121</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R122.htm</HtmlFileName>
      <LongName>240904047 - Disclosure - EMPLOYEE BENEFITS OBLIGATIONS - Plan Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEEBENEFITSOBLIGATIONSPlanAssetsDetails</Role>
      <ShortName>EMPLOYEE BENEFITS OBLIGATIONS - Plan Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>122</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R123.htm</HtmlFileName>
      <LongName>240914048 - Disclosure - EMPLOYEE BENEFITS OBLIGATIONS - Significant Assumptions Weighted (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEEBENEFITSOBLIGATIONSSignificantAssumptionsWeightedDetails</Role>
      <ShortName>EMPLOYEE BENEFITS OBLIGATIONS - Significant Assumptions Weighted (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>123</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R124.htm</HtmlFileName>
      <LongName>240924049 - Disclosure - EMPLOYEE BENEFITS OBLIGATIONS - Future Mortality Rate (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEEBENEFITSOBLIGATIONSFutureMortalityRateDetails</Role>
      <ShortName>EMPLOYEE BENEFITS OBLIGATIONS - Future Mortality Rate (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>124</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R125.htm</HtmlFileName>
      <LongName>240934050 - Disclosure - EMPLOYEE BENEFITS OBLIGATIONS - Significant Assumptions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEEBENEFITSOBLIGATIONSSignificantAssumptionsDetails</Role>
      <ShortName>EMPLOYEE BENEFITS OBLIGATIONS - Significant Assumptions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>125</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R126.htm</HtmlFileName>
      <LongName>240944051 - Disclosure - EMPLOYEE BENEFITS OBLIGATIONS - Expected Employer Contributions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEEBENEFITSOBLIGATIONSExpectedEmployerContributionsDetails</Role>
      <ShortName>EMPLOYEE BENEFITS OBLIGATIONS - Expected Employer Contributions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>126</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R127.htm</HtmlFileName>
      <LongName>240974052 - Disclosure - OTHER NON-CURRENT LIABILITIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/OTHERNONCURRENTLIABILITIESDetails</Role>
      <ShortName>OTHER NON-CURRENT LIABILITIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/OTHERNONCURRENTLIABILITIESTables</ParentRole>
      <Position>127</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R128.htm</HtmlFileName>
      <LongName>241004053 - Disclosure - SUPPLEMENTARY CASH FLOWS INFORMATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SUPPLEMENTARYCASHFLOWSINFORMATIONDetails</Role>
      <ShortName>SUPPLEMENTARY CASH FLOWS INFORMATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/SUPPLEMENTARYCASHFLOWSINFORMATIONTables</ParentRole>
      <Position>128</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R129.htm</HtmlFileName>
      <LongName>241034054 - Disclosure - ACCUMULATED OTHER COMPREHENSIVE INCOME (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/ACCUMULATEDOTHERCOMPREHENSIVEINCOMEDetails</Role>
      <ShortName>ACCUMULATED OTHER COMPREHENSIVE INCOME (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/ACCUMULATEDOTHERCOMPREHENSIVEINCOMETables</ParentRole>
      <Position>129</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R130.htm</HtmlFileName>
      <LongName>241064055 - Disclosure - SHARE-BASED PAYMENTS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SHAREBASEDPAYMENTSNarrativeDetails</Role>
      <ShortName>SHARE-BASED PAYMENTS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>130</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R131.htm</HtmlFileName>
      <LongName>241074056 - Disclosure - SHARE-BASED PAYMENTS - Share-based Compensation Cost (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SHAREBASEDPAYMENTSSharebasedCompensationCostDetails</Role>
      <ShortName>SHARE-BASED PAYMENTS - Share-based Compensation Cost (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>131</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R132.htm</HtmlFileName>
      <LongName>241084057 - Disclosure - SHARE-BASED PAYMENTS - ESOP Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SHAREBASEDPAYMENTSESOPActivityDetails</Role>
      <ShortName>SHARE-BASED PAYMENTS - ESOP Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>132</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R133.htm</HtmlFileName>
      <LongName>241094058 - Disclosure - SHARE-BASED PAYMENTS - ESOP Summarized (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SHAREBASEDPAYMENTSESOPSummarizedDetails</Role>
      <ShortName>SHARE-BASED PAYMENTS - ESOP Summarized (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>133</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R134.htm</HtmlFileName>
      <LongName>241104059 - Disclosure - SHARE-BASED PAYMENTS - Assumptions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SHAREBASEDPAYMENTSAssumptionsDetails</Role>
      <ShortName>SHARE-BASED PAYMENTS - Assumptions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>134</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R135.htm</HtmlFileName>
      <LongName>241114060 - Disclosure - SHARE-BASED PAYMENTS - DSU Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SHAREBASEDPAYMENTSDSUActivityDetails</Role>
      <ShortName>SHARE-BASED PAYMENTS - DSU Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>135</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R136.htm</HtmlFileName>
      <LongName>241124061 - Disclosure - SHARE-BASED PAYMENTS - RSU and PSU Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/SHAREBASEDPAYMENTSRSUandPSUActivityDetails</Role>
      <ShortName>SHARE-BASED PAYMENTS - RSU and PSU Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>136</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R137.htm</HtmlFileName>
      <LongName>241154062 - Disclosure - EMPLOYEE COMPENSATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/EMPLOYEECOMPENSATIONDetails</Role>
      <ShortName>EMPLOYEE COMPENSATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/EMPLOYEECOMPENSATIONTables</ParentRole>
      <Position>137</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R138.htm</HtmlFileName>
      <LongName>241184063 - Disclosure - GOVERNMENT PARTICIPATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/GOVERNMENTPARTICIPATIONDetails</Role>
      <ShortName>GOVERNMENT PARTICIPATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/GOVERNMENTPARTICIPATIONTables</ParentRole>
      <Position>138</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R139.htm</HtmlFileName>
      <LongName>241214064 - Disclosure - IMPAIRMENT OF NON-FINANCIAL ASSETS - Changes In Goodwill (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/IMPAIRMENTOFNONFINANCIALASSETSChangesInGoodwillDetails</Role>
      <ShortName>IMPAIRMENT OF NON-FINANCIAL ASSETS - Changes In Goodwill (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>139</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R140.htm</HtmlFileName>
      <LongName>241224065 - Disclosure - IMPAIRMENT OF NON-FINANCIAL ASSETS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/IMPAIRMENTOFNONFINANCIALASSETSNarrativeDetails</Role>
      <ShortName>IMPAIRMENT OF NON-FINANCIAL ASSETS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>140</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R141.htm</HtmlFileName>
      <LongName>241254066 - Disclosure - CONTINGENCIES AND COMMITMENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/CONTINGENCIESANDCOMMITMENTSDetails</Role>
      <ShortName>CONTINGENCIES AND COMMITMENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/CONTINGENCIESANDCOMMITMENTSTables</ParentRole>
      <Position>141</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R142.htm</HtmlFileName>
      <LongName>241284067 - Disclosure - FAIR VALUE OF FINANCIAL INSTRUMENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSDetails</Role>
      <ShortName>FAIR VALUE OF FINANCIAL INSTRUMENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/FAIRVALUEOFFINANCIALINSTRUMENTSTables</ParentRole>
      <Position>142</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R143.htm</HtmlFileName>
      <LongName>241314068 - Disclosure - CAPITAL RISK MANAGEMENT (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/CAPITALRISKMANAGEMENTDetails</Role>
      <ShortName>CAPITAL RISK MANAGEMENT (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/CAPITALRISKMANAGEMENTTables</ParentRole>
      <Position>143</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R144.htm</HtmlFileName>
      <LongName>241344069 - Disclosure - FINANCIAL RISK MANAGEMENT - Credit Risk (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FINANCIALRISKMANAGEMENTCreditRiskDetails</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT - Credit Risk (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>144</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R145.htm</HtmlFileName>
      <LongName>241354070 - Disclosure - FINANCIAL RISK MANAGEMENT - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FINANCIALRISKMANAGEMENTNarrativeDetails</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>145</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R146.htm</HtmlFileName>
      <LongName>241364071 - Disclosure - FINANCIAL RISK MANAGEMENT - Maturity Analysis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FINANCIALRISKMANAGEMENTMaturityAnalysisDetails</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT - Maturity Analysis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>146</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R147.htm</HtmlFileName>
      <LongName>241374072 - Disclosure - FINANCIAL RISK MANAGEMENT - Forward Foreign Currency Contracts (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FINANCIALRISKMANAGEMENTForwardForeignCurrencyContractsDetails</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT - Forward Foreign Currency Contracts (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>147</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R148.htm</HtmlFileName>
      <LongName>241384073 - Disclosure - FINANCIAL RISK MANAGEMENT - Net Income and Other Comprehensive Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FINANCIALRISKMANAGEMENTNetIncomeandOtherComprehensiveIncomeDetails</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT - Net Income and Other Comprehensive Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>148</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R149.htm</HtmlFileName>
      <LongName>241394074 - Disclosure - FINANCIAL RISK MANAGEMENT - Letters Of Credit And Guarantees (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/FINANCIALRISKMANAGEMENTLettersOfCreditAndGuaranteesDetails</Role>
      <ShortName>FINANCIAL RISK MANAGEMENT - Letters Of Credit And Guarantees (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>149</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R150.htm</HtmlFileName>
      <LongName>241424075 - Disclosure - RELATED PARTY RELATIONSHIPS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/RELATEDPARTYRELATIONSHIPSDetails</Role>
      <ShortName>RELATED PARTY RELATIONSHIPS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.cae.com/role/RELATEDPARTYRELATIONSHIPSTables</ParentRole>
      <Position>150</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R151.htm</HtmlFileName>
      <LongName>241454076 - Disclosure - RELATED PARTY TRANSACTIONS - Outstanding Balances (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/RELATEDPARTYTRANSACTIONSOutstandingBalancesDetails</Role>
      <ShortName>RELATED PARTY TRANSACTIONS - Outstanding Balances (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>151</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R152.htm</HtmlFileName>
      <LongName>241464077 - Disclosure - RELATED PARTY TRANSACTIONS - Transactions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/RELATEDPARTYTRANSACTIONSTransactionsDetails</Role>
      <ShortName>RELATED PARTY TRANSACTIONS - Transactions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>152</Position>
    </Report>
    <Report instance="cae-20210331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R153.htm</HtmlFileName>
      <LongName>241474078 - Disclosure - RELATED PARTY TRANSACTIONS - Compensation Of Key Management Personnel (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.cae.com/role/RELATEDPARTYTRANSACTIONSCompensationOfKeyManagementPersonnelDetails</Role>
      <ShortName>RELATED PARTY TRANSACTIONS - Compensation Of Key Management Personnel (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>153</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="40-F" original="cae-20210331.htm">cae-20210331.htm</File>
    <File doctype="40-F" original="cae-20210331_d2.htm">cae-20210331_d2.htm</File>
    <File>a995-certsection302ceosign.htm</File>
    <File>a996-certsection302cfosign.htm</File>
    <File>a997-certsection906ceosign.htm</File>
    <File>a998-certsection906cfosign.htm</File>
    <File>cae-20210331.xsd</File>
    <File>cae-20210331_cal.xml</File>
    <File>cae-20210331_def.xml</File>
    <File>cae-20210331_lab.xml</File>
    <File>cae-20210331_pre.xml</File>
    <File>cae_033121xex3mda.htm</File>
    <File>caeaif2021.htm</File>
    <File>pwcconsent2021.htm</File>
  </InputFiles>
  <SupplementalFiles>
    <File>cae-20210331_g1.gif</File>
    <File>cae-20210331_g2.gif</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy>http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/country/2020-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
