<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.22.0.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>795</ContextCount>
  <ElementCount>770</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>210</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>6</UnitCount>
  <MyReports>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000 - Document - Document And Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document And Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>001 - Statement - Consolidated Statements of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ConsolidatedIncomeStatement</Role>
      <ShortName>Consolidated Statements of Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>002 - Statement - Consolidated Statements of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ConsolidatedComprehensiveIncome</Role>
      <ShortName>Consolidated Statements of Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>003 - Statement - Consolidated Statements of Changes in Shareholders??? Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ShareholdersEquityType2or3</Role>
      <ShortName>Consolidated Statements of Changes in Shareholders??? Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>004 - Statement - Consolidated Statements of Changes in Shareholders??? Equity (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ShareholdersEquityType2or3_Parentheticals</Role>
      <ShortName>Consolidated Statements of Changes in Shareholders??? Equity (Parentheticals)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>005 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ConsolidatedBalanceSheet</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>006 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ConsolidatedCashFlow</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>007 - Disclosure - Background of the Company</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/BackgroundoftheCompany</Role>
      <ShortName>Background of the Company</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>008 - Disclosure - Transaction</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/Transaction</Role>
      <ShortName>Transaction</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>009 - Disclosure - Basis of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/BasisofPresentation</Role>
      <ShortName>Basis of Presentation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>010 - Disclosure - Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SignificantAccountingPolicies</Role>
      <ShortName>Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>011 - Disclosure - Critical Accounting Judgments and Estimates</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/CriticalAccountingJudgmentsandEstimates</Role>
      <ShortName>Critical Accounting Judgments and Estimates</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>012 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>013 - Disclosure - Operating Expenses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OperatingExpenses</Role>
      <ShortName>Operating Expenses</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>014 - Disclosure - Other Operating Gains (Losses), Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherOperatingGainsLossesNet</Role>
      <ShortName>Other Operating Gains (Losses), Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>015 - Disclosure - Interest Expense</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/InterestExpense</Role>
      <ShortName>Interest Expense</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>016 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>017 - Disclosure - Trade and Other Receivables</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/TradeandOtherReceivables</Role>
      <ShortName>Trade and Other Receivables</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>018 - Disclosure - Other Current Financial Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherCurrentFinancialAssets</Role>
      <ShortName>Other Current Financial Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>019 - Disclosure - Prepaid Expenses and Other Current Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/PrepaidExpensesandOtherCurrentAssets</Role>
      <ShortName>Prepaid Expenses and Other Current Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>020 - Disclosure - Other Long-Term Financial Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherLongTermFinancialAssets</Role>
      <ShortName>Other Long-Term Financial Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>021 - Disclosure - Other Long-Term Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherLongTermAssets</Role>
      <ShortName>Other Long-Term Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>022 - Disclosure - Satellites, Property and other Equipment</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SatellitesPropertyandotherEquipment</Role>
      <ShortName>Satellites, Property and other Equipment</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>023 - Disclosure - Intangible Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/IntangibleAssets</Role>
      <ShortName>Intangible Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>024 - Disclosure - Goodwill</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/Goodwill</Role>
      <ShortName>Goodwill</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>025 - Disclosure - Trade and Other Payables</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/TradeandOtherPayables</Role>
      <ShortName>Trade and Other Payables</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>026 - Disclosure - Other Current Financial Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherCurrentFinancialLiabilities</Role>
      <ShortName>Other Current Financial Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>027 - Disclosure - Other Current Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherCurrentLiabilities</Role>
      <ShortName>Other Current Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>028 - Disclosure - Other Long-Term Financial Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherLongTermFinancialLiabilities</Role>
      <ShortName>Other Long-Term Financial Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>029 - Disclosure - Other Long-Term Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherLongTermLiabilities</Role>
      <ShortName>Other Long-Term Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>030 - Disclosure - Indebtedness</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/Indebtedness</Role>
      <ShortName>Indebtedness</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>031 - Disclosure - Share Capital</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ShareCapital</Role>
      <ShortName>Share Capital</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>032 - Disclosure - Non-Controlling Interest</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/NonControllingInterest</Role>
      <ShortName>Non-Controlling Interest</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>033 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/EarningsPerShare</Role>
      <ShortName>Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>034 - Disclosure - Government Grant</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/GovernmentGrant</Role>
      <ShortName>Government Grant</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>035 - Disclosure - Capital Disclosures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/CapitalDisclosures</Role>
      <ShortName>Capital Disclosures</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>036 - Disclosure - Financial Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/FinancialInstruments</Role>
      <ShortName>Financial Instruments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>037 - Disclosure - Share-Based Compensation Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ShareBasedCompensationPlans</Role>
      <ShortName>Share-Based Compensation Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>038 - Disclosure - Employee Benefit Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/EmployeeBenefitPlans</Role>
      <ShortName>Employee Benefit Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>039 - Disclosure - Supplemental Cash Flow Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SupplementalCashFlowInformation</Role>
      <ShortName>Supplemental Cash Flow Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>040 - Disclosure - Commitments and Contingent Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/CommitmentsandContingentLiabilities</Role>
      <ShortName>Commitments and Contingent Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>041 - Disclosure - Subsidiaries</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/Subsidiaries</Role>
      <ShortName>Subsidiaries</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>042 - Disclosure - Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/RelatedPartyTransactions</Role>
      <ShortName>Related Party Transactions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>043 - Disclosure - Accounting Policies, by Policy (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/AccountingPoliciesByPolicy</Role>
      <ShortName>Accounting Policies, by Policy (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SignificantAccountingPolicies</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>044 - Disclosure - Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SignificantAccountingPoliciesTables</Role>
      <ShortName>Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SignificantAccountingPolicies</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>045 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SegmentInformation</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>046 - Disclosure - Operating Expenses (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OperatingExpensesTables</Role>
      <ShortName>Operating Expenses (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OperatingExpenses</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>047 - Disclosure - Other Operating Gains (Losses), Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherOperatingGainsLossesNetTables</Role>
      <ShortName>Other Operating Gains (Losses), Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherOperatingGainsLossesNet</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>048 - Disclosure - Interest Expense (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/InterestExpenseTables</Role>
      <ShortName>Interest Expense (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/InterestExpense</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>049 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/IncomeTaxesTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IncomeTaxes</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>050 - Disclosure - Trade and Other Receivables (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/TradeandOtherReceivablesTables</Role>
      <ShortName>Trade and Other Receivables (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/TradeandOtherReceivables</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>051 - Disclosure - Other Current Financial Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherCurrentFinancialAssetsTables</Role>
      <ShortName>Other Current Financial Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherCurrentFinancialAssets</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>052 - Disclosure - Prepaid Expenses and Other Current Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/PrepaidExpensesandOtherCurrentAssetsTables</Role>
      <ShortName>Prepaid Expenses and Other Current Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/PrepaidExpensesandOtherCurrentAssets</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>053 - Disclosure - Other Long-Term Financial Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherLongTermFinancialAssetsTables</Role>
      <ShortName>Other Long-Term Financial Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherLongTermFinancialAssets</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>054 - Disclosure - Other Long-Term Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherLongTermAssetsTables</Role>
      <ShortName>Other Long-Term Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherLongTermAssets</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>055 - Disclosure - Satellites, Property and other Equipment (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SatellitesPropertyandotherEquipmentTables</Role>
      <ShortName>Satellites, Property and other Equipment (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SatellitesPropertyandotherEquipment</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>056 - Disclosure - Intangible Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/IntangibleAssetsTables</Role>
      <ShortName>Intangible Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IntangibleAssets</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>057 - Disclosure - Goodwill (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/GoodwillTables</Role>
      <ShortName>Goodwill (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/Goodwill</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>058 - Disclosure - Trade and Other Payables (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/TradeandOtherPayablesTables</Role>
      <ShortName>Trade and Other Payables (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/TradeandOtherPayables</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>059 - Disclosure - Other Current Financial Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherCurrentFinancialLiabilitiesTables</Role>
      <ShortName>Other Current Financial Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherCurrentFinancialLiabilities</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>060 - Disclosure - Other Current Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherCurrentLiabilitiesTables</Role>
      <ShortName>Other Current Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherCurrentLiabilities</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>061 - Disclosure - Other Long-Term Financial Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherLongTermFinancialLiabilitiesTables</Role>
      <ShortName>Other Long-Term Financial Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherLongTermFinancialLiabilities</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>062 - Disclosure - Other Long-Term Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherLongTermLiabilitiesTables</Role>
      <ShortName>Other Long-Term Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherLongTermLiabilities</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>063 - Disclosure - Indebtedness (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/IndebtednessTables</Role>
      <ShortName>Indebtedness (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/Indebtedness</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>064 - Disclosure - Share Capital (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ShareCapitalTables</Role>
      <ShortName>Share Capital (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/ShareCapital</ParentRole>
      <Position>65</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>065 - Disclosure - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/EarningsPerShareTables</Role>
      <ShortName>Earnings Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/EarningsPerShare</ParentRole>
      <Position>66</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>066 - Disclosure - Capital Disclosures (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/CapitalDisclosuresTables</Role>
      <ShortName>Capital Disclosures (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/CapitalDisclosures</ParentRole>
      <Position>67</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>067 - Disclosure - Financial Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/FinancialInstrumentsTables</Role>
      <ShortName>Financial Instruments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/FinancialInstruments</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>068 - Disclosure - Share-Based Compensation Plans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ShareBasedCompensationPlansTables</Role>
      <ShortName>Share-Based Compensation Plans (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/ShareBasedCompensationPlans</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>069 - Disclosure - Employee Benefit Plans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/EmployeeBenefitPlansTables</Role>
      <ShortName>Employee Benefit Plans (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/EmployeeBenefitPlans</ParentRole>
      <Position>70</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>070 - Disclosure - Supplemental Cash Flow Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SupplementalCashFlowInformationTables</Role>
      <ShortName>Supplemental Cash Flow Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SupplementalCashFlowInformation</ParentRole>
      <Position>71</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>071 - Disclosure - Commitments and Contingent Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/CommitmentsandContingentLiabilitiesTables</Role>
      <ShortName>Commitments and Contingent Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/CommitmentsandContingentLiabilities</ParentRole>
      <Position>72</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>072 - Disclosure - Subsidiaries (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SubsidiariesTables</Role>
      <ShortName>Subsidiaries (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/Subsidiaries</ParentRole>
      <Position>73</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>073 - Disclosure - Related Party Transactions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/RelatedPartyTransactionsTables</Role>
      <ShortName>Related Party Transactions (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.telesat.com/role/RelatedPartyTransactions</ParentRole>
      <Position>74</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>074 - Disclosure - Background of the Company (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/BackgroundoftheCompanyDetails</Role>
      <ShortName>Background of the Company (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/BackgroundoftheCompany</ParentRole>
      <Position>75</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>075 - Disclosure - Transaction (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/TransactionDetails</Role>
      <ShortName>Transaction (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/Transaction</ParentRole>
      <Position>76</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>076 - Disclosure - Significant Accounting Policies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SignificantAccountingPoliciesDetails</Role>
      <ShortName>Significant Accounting Policies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SignificantAccountingPoliciesTables</ParentRole>
      <Position>77</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>077 - Disclosure - Significant Accounting Policies (Details) - Schedule of satellites, property and other equipment</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofsatellitespropertyandotherequipmentTable</Role>
      <ShortName>Significant Accounting Policies (Details) - Schedule of satellites, property and other equipment</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SignificantAccountingPoliciesTables</ParentRole>
      <Position>78</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>078 - Disclosure - Significant Accounting Policies (Details) - Schedule of finite life intangible assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleoffinitelifeintangibleassetsTable</Role>
      <ShortName>Significant Accounting Policies (Details) - Schedule of finite life intangible assets</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SignificantAccountingPoliciesTables</ParentRole>
      <Position>79</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>079 - Disclosure - Critical Accounting Judgments and Estimates (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/CriticalAccountingJudgmentsandEstimatesDetails</Role>
      <ShortName>Critical Accounting Judgments and Estimates (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/CriticalAccountingJudgmentsandEstimates</ParentRole>
      <Position>80</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>080 - Disclosure - Segment Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SegmentInformationDetails</Role>
      <ShortName>Segment Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SegmentInformationTables</ParentRole>
      <Position>81</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>081 - Disclosure - Segment Information (Details) - Schedule of revenue derived from services</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofrevenuederivedfromservicesTable</Role>
      <ShortName>Segment Information (Details) - Schedule of revenue derived from services</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SegmentInformationTables</ParentRole>
      <Position>82</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>082 - Disclosure - Segment Information (Details) - Schedule of equipment sales within services</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofequipmentsaleswithinservicesTable</Role>
      <ShortName>Segment Information (Details) - Schedule of equipment sales within services</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SegmentInformationTables</ParentRole>
      <Position>83</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>083 - Disclosure - Segment Information (Details) - Schedule of geographic regions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofgeographicregionsTable</Role>
      <ShortName>Segment Information (Details) - Schedule of geographic regions</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SegmentInformationTables</ParentRole>
      <Position>84</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>084 - Disclosure - Operating Expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OperatingExpensesDetails</Role>
      <ShortName>Operating Expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OperatingExpensesTables</ParentRole>
      <Position>85</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>085 - Disclosure - Operating Expenses (Details) - Schedule of operating expenses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofoperatingexpensesTable</Role>
      <ShortName>Operating Expenses (Details) - Schedule of operating expenses</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OperatingExpensesTables</ParentRole>
      <Position>86</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>086 - Disclosure - Operating Expenses (Details) - Schedule of cost of equipment sales included in the cost of sales</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofcostofequipmentsalesincludedinthecostofsalesTable</Role>
      <ShortName>Operating Expenses (Details) - Schedule of cost of equipment sales included in the cost of sales</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OperatingExpensesTables</ParentRole>
      <Position>87</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>087 - Disclosure - Other Operating Gains (Losses), Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherOperatingGainsLossesNetDetails</Role>
      <ShortName>Other Operating Gains (Losses), Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherOperatingGainsLossesNetTables</ParentRole>
      <Position>88</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>088 - Disclosure - Other Operating Gains (Losses), Net (Details) - Schedule of other operating gains (losses), net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofotheroperatinggainslossesnetTable</Role>
      <ShortName>Other Operating Gains (Losses), Net (Details) - Schedule of other operating gains (losses), net</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherOperatingGainsLossesNetTables</ParentRole>
      <Position>89</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>089 - Disclosure - Interest Expense (Details) - Schedule of interest expense</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofinterestexpenseTable</Role>
      <ShortName>Interest Expense (Details) - Schedule of interest expense</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/InterestExpenseTables</ParentRole>
      <Position>90</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>090 - Disclosure - Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/IncomeTaxesDetails</Role>
      <ShortName>Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IncomeTaxesTables</ParentRole>
      <Position>91</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>091 - Disclosure - Income Taxes (Details) - Schedule of components of income tax expense</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofcomponentsofincometaxexpenseTable</Role>
      <ShortName>Income Taxes (Details) - Schedule of components of income tax expense</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IncomeTaxesTables</ParentRole>
      <Position>92</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>092 - Disclosure - Income Taxes (Details) - Schedule of reconciliation of statutory income tax rate</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofreconciliationofstatutoryincometaxrateTable</Role>
      <ShortName>Income Taxes (Details) - Schedule of reconciliation of statutory income tax rate</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IncomeTaxesTables</ParentRole>
      <Position>93</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>093 - Disclosure - Income Taxes (Details) - Schedule of tax effects of temporary differences between carrying amounts of assets and liabilities for accounting purposes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleoftaxeffectsoftemporarydifferencesbetweencarryingamountsofassetsandliabilitiesforaccountingpurposesTable</Role>
      <ShortName>Income Taxes (Details) - Schedule of tax effects of temporary differences between carrying amounts of assets and liabilities for accounting purposes</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IncomeTaxesTables</ParentRole>
      <Position>94</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>094 - Disclosure - Trade and Other Receivables (Details) - Schedule of trade and other receivables</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleoftradeandotherreceivablesTable</Role>
      <ShortName>Trade and Other Receivables (Details) - Schedule of trade and other receivables</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/TradeandOtherReceivablesTables</ParentRole>
      <Position>95</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>095 - Disclosure - Trade and Other Receivables (Details) - Schedule of allowance for doubtful accounts</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofallowancefordoubtfulaccountsTable</Role>
      <ShortName>Trade and Other Receivables (Details) - Schedule of allowance for doubtful accounts</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/TradeandOtherReceivablesTables</ParentRole>
      <Position>96</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>096 - Disclosure - Other Current Financial Assets (Details) - Schedule of other current financial assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofothercurrentfinancialassetsTable</Role>
      <ShortName>Other Current Financial Assets (Details) - Schedule of other current financial assets</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherCurrentFinancialAssetsTables</ParentRole>
      <Position>97</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R98.htm</HtmlFileName>
      <LongName>097 - Disclosure - Prepaid Expenses and Other Current Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/PrepaidExpensesandOtherCurrentAssetsDetails</Role>
      <ShortName>Prepaid Expenses and Other Current Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/PrepaidExpensesandOtherCurrentAssetsTables</ParentRole>
      <Position>98</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R99.htm</HtmlFileName>
      <LongName>098 - Disclosure - Prepaid Expenses and Other Current Assets (Details) - Schedule of prepaid expenses and other current assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofprepaidexpensesandothercurrentassetsTable</Role>
      <ShortName>Prepaid Expenses and Other Current Assets (Details) - Schedule of prepaid expenses and other current assets</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/PrepaidExpensesandOtherCurrentAssetsTables</ParentRole>
      <Position>99</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R100.htm</HtmlFileName>
      <LongName>099 - Disclosure - Other Long-Term Financial Assets (Details) - Schedule of other long-term financial assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofotherlongtermfinancialassetsTable</Role>
      <ShortName>Other Long-Term Financial Assets (Details) - Schedule of other long-term financial assets</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherLongTermFinancialAssetsTables</ParentRole>
      <Position>100</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R101.htm</HtmlFileName>
      <LongName>100 - Disclosure - Other Long-Term Assets (Details) - Schedule of other long-term assets of other long-term financial assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofotherlongtermassetsofotherlongtermfinancialassetsTable</Role>
      <ShortName>Other Long-Term Assets (Details) - Schedule of other long-term assets of other long-term financial assets</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherLongTermAssetsTables</ParentRole>
      <Position>101</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R102.htm</HtmlFileName>
      <LongName>101 - Disclosure - Satellites, Property and other Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SatellitesPropertyandotherEquipmentDetails</Role>
      <ShortName>Satellites, Property and other Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SatellitesPropertyandotherEquipmentTables</ParentRole>
      <Position>102</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R103.htm</HtmlFileName>
      <LongName>102 - Disclosure - Satellites, Property and other Equipment (Details) - Schedule of satellites, property and other equipment</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofsatellitespropertyandotherequipmentTable0</Role>
      <ShortName>Satellites, Property and other Equipment (Details) - Schedule of satellites, property and other equipment</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SatellitesPropertyandotherEquipmentTables</ParentRole>
      <Position>103</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R104.htm</HtmlFileName>
      <LongName>103 - Disclosure - Intangible Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/IntangibleAssetsDetails</Role>
      <ShortName>Intangible Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IntangibleAssetsTables</ParentRole>
      <Position>104</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R105.htm</HtmlFileName>
      <LongName>104 - Disclosure - Intangible Assets (Details) - Schedule of indefinite life intangible assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofindefinitelifeintangibleassetsTable</Role>
      <ShortName>Intangible Assets (Details) - Schedule of indefinite life intangible assets</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IntangibleAssetsTables</ParentRole>
      <Position>105</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R106.htm</HtmlFileName>
      <LongName>105 - Disclosure - Intangible Assets (Details) - Schedule of finite life intangible assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleoffinitelifeintangibleassetsTable0</Role>
      <ShortName>Intangible Assets (Details) - Schedule of finite life intangible assets</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IntangibleAssetsTables</ParentRole>
      <Position>106</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R107.htm</HtmlFileName>
      <LongName>106 - Disclosure - Intangible Assets (Details) - Schedule of indefinite and finite life intangible assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofindefiniteandfinitelifeintangibleassetsTable</Role>
      <ShortName>Intangible Assets (Details) - Schedule of indefinite and finite life intangible assets</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IntangibleAssetsTables</ParentRole>
      <Position>107</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R108.htm</HtmlFileName>
      <LongName>107 - Disclosure - Intangible Assets (Details) - Schedule of remaining useful lives of the intangible assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofremainingusefullivesoftheintangibleassetsTable</Role>
      <ShortName>Intangible Assets (Details) - Schedule of remaining useful lives of the intangible assets</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IntangibleAssetsTables</ParentRole>
      <Position>108</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R109.htm</HtmlFileName>
      <LongName>108 - Disclosure - Intangible Assets (Details) - Schedule of discount rates</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofdiscountratesTable</Role>
      <ShortName>Intangible Assets (Details) - Schedule of discount rates</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IntangibleAssetsTables</ParentRole>
      <Position>109</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R110.htm</HtmlFileName>
      <LongName>109 - Disclosure - Intangible Assets (Details) - Schedule of growth rate assumptions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofgrowthrateassumptionsTable</Role>
      <ShortName>Intangible Assets (Details) - Schedule of growth rate assumptions</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IntangibleAssetsTables</ParentRole>
      <Position>110</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R111.htm</HtmlFileName>
      <LongName>110 - Disclosure - Goodwill (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/GoodwillDetails</Role>
      <ShortName>Goodwill (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/GoodwillTables</ParentRole>
      <Position>111</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R112.htm</HtmlFileName>
      <LongName>111 - Disclosure - Goodwill (Details) - Schedule of management uses a weighted average cost of capital as a discount rate</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofmanagementusesaweightedaveragecostofcapitalasadiscountrateTable</Role>
      <ShortName>Goodwill (Details) - Schedule of management uses a weighted average cost of capital as a discount rate</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/GoodwillTables</ParentRole>
      <Position>112</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R113.htm</HtmlFileName>
      <LongName>112 - Disclosure - Trade and Other Payables (Details) - Schedule of trade and other payables</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleoftradeandotherpayablesTable</Role>
      <ShortName>Trade and Other Payables (Details) - Schedule of trade and other payables</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/TradeandOtherPayablesTables</ParentRole>
      <Position>113</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R114.htm</HtmlFileName>
      <LongName>113 - Disclosure - Other Current Financial Liabilities (Details) - Schedule of other current financial liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofothercurrentfinancialliabilitiesTable</Role>
      <ShortName>Other Current Financial Liabilities (Details) - Schedule of other current financial liabilities</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherCurrentFinancialLiabilitiesTables</ParentRole>
      <Position>114</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R115.htm</HtmlFileName>
      <LongName>114 - Disclosure - Other Current Liabilities (Details) - Schedule of other current liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofothercurrentliabilitiesTable</Role>
      <ShortName>Other Current Liabilities (Details) - Schedule of other current liabilities</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherCurrentLiabilitiesTables</ParentRole>
      <Position>115</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R116.htm</HtmlFileName>
      <LongName>115 - Disclosure - Other Long-Term Financial Liabilities (Details) - Schedule of other long-term financial liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofotherlongtermfinancialliabilitiesTable</Role>
      <ShortName>Other Long-Term Financial Liabilities (Details) - Schedule of other long-term financial liabilities</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherLongTermFinancialLiabilitiesTables</ParentRole>
      <Position>116</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R117.htm</HtmlFileName>
      <LongName>116 - Disclosure - Other Long-Term Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/OtherLongTermLiabilitiesDetails</Role>
      <ShortName>Other Long-Term Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherLongTermLiabilitiesTables</ParentRole>
      <Position>117</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R118.htm</HtmlFileName>
      <LongName>117 - Disclosure - Other Long-Term Liabilities (Details) - Schedule of other long-term liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofotherlongtermliabilitiesTable</Role>
      <ShortName>Other Long-Term Liabilities (Details) - Schedule of other long-term liabilities</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherLongTermLiabilitiesTables</ParentRole>
      <Position>118</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R119.htm</HtmlFileName>
      <LongName>118 - Disclosure - Other Long-Term Liabilities (Details) - Schedule of expects the backlog</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofexpectsthebacklogTable</Role>
      <ShortName>Other Long-Term Liabilities (Details) - Schedule of expects the backlog</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/OtherLongTermLiabilitiesTables</ParentRole>
      <Position>119</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R120.htm</HtmlFileName>
      <LongName>119 - Disclosure - Indebtedness (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/IndebtednessDetails</Role>
      <ShortName>Indebtedness (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IndebtednessTables</ParentRole>
      <Position>120</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R121.htm</HtmlFileName>
      <LongName>120 - Disclosure - Indebtedness (Details) - Schedule of indebtedness</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofindebtednessTable</Role>
      <ShortName>Indebtedness (Details) - Schedule of indebtedness</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IndebtednessTables</ParentRole>
      <Position>121</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R122.htm</HtmlFileName>
      <LongName>121 - Disclosure - Indebtedness (Details) - Schedule of indebtedness (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofindebtednessTable_Parentheticals</Role>
      <ShortName>Indebtedness (Details) - Schedule of indebtedness (Parentheticals)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IndebtednessTables</ParentRole>
      <Position>122</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R123.htm</HtmlFileName>
      <LongName>122 - Disclosure - Indebtedness (Details) - Schedule of short-term and long-term portions of deferred financing costs, prepayment options and loss on repayment</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofshorttermandlongtermportionsofdeferredfinancingcostsprepaymentoptionsandlossonrepaymentTable</Role>
      <ShortName>Indebtedness (Details) - Schedule of short-term and long-term portions of deferred financing costs, prepayment options and loss on repayment</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/IndebtednessTables</ParentRole>
      <Position>123</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R124.htm</HtmlFileName>
      <LongName>123 - Disclosure - Share Capital (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ShareCapitalDetails</Role>
      <ShortName>Share Capital (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/ShareCapitalTables</ParentRole>
      <Position>124</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R125.htm</HtmlFileName>
      <LongName>124 - Disclosure - Share Capital (Details) - Schedule of number of shares and stated value of outstanding shares</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofnumberofsharesandstatedvalueofoutstandingsharesTable</Role>
      <ShortName>Share Capital (Details) - Schedule of number of shares and stated value of outstanding shares</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/ShareCapitalTables</ParentRole>
      <Position>125</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R126.htm</HtmlFileName>
      <LongName>125 - Disclosure - Share Capital (Details) - Schedule of number of shares and stated value of outstanding shares</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofnumberofsharesandstatedvalueofoutstandingsharesTable0</Role>
      <ShortName>Share Capital (Details) - Schedule of number of shares and stated value of outstanding shares</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/ShareCapitalTables</ParentRole>
      <Position>126</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R127.htm</HtmlFileName>
      <LongName>126 - Disclosure - Share Capital (Details) - Schedule of number of shares and stated value of outstanding shares</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofnumberofsharesandstatedvalueofoutstandingsharesTable00</Role>
      <ShortName>Share Capital (Details) - Schedule of number of shares and stated value of outstanding shares</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/ShareCapitalTables</ParentRole>
      <Position>127</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R128.htm</HtmlFileName>
      <LongName>127 - Disclosure - Non-Controlling Interest (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/NonControllingInterestDetails</Role>
      <ShortName>Non-Controlling Interest (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/NonControllingInterest</ParentRole>
      <Position>128</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R129.htm</HtmlFileName>
      <LongName>128 - Disclosure -  Earnings Per Share (Details) - Shedule of basic and diluted per share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SheduleofbasicanddilutedpershareTable</Role>
      <ShortName>Earnings Per Share (Details) - Shedule of basic and diluted per share</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/EarningsPerShareTables</ParentRole>
      <Position>129</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R130.htm</HtmlFileName>
      <LongName>129 - Disclosure - Government Grant (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/GovernmentGrantDetails</Role>
      <ShortName>Government Grant (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/GovernmentGrant</ParentRole>
      <Position>130</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R131.htm</HtmlFileName>
      <LongName>130 - Disclosure - Capital Disclosures (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/CapitalDisclosuresDetails</Role>
      <ShortName>Capital Disclosures (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/CapitalDisclosuresTables</ParentRole>
      <Position>131</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R132.htm</HtmlFileName>
      <LongName>131 - Disclosure - Capital Disclosures (Details) - Schedule of capital</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofcapitalTable</Role>
      <ShortName>Capital Disclosures (Details) - Schedule of capital</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/CapitalDisclosuresTables</ParentRole>
      <Position>132</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R133.htm</HtmlFileName>
      <LongName>132 - Disclosure - Financial Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/FinancialInstrumentsDetails</Role>
      <ShortName>Financial Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/FinancialInstrumentsTables</ParentRole>
      <Position>133</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R134.htm</HtmlFileName>
      <LongName>133 - Disclosure - Financial Instruments (Details) - Schedule maturity of financial assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/SchedulematurityoffinancialassetsTable</Role>
      <ShortName>Financial Instruments (Details) - Schedule maturity of financial assets</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/FinancialInstrumentsTables</ParentRole>
      <Position>134</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R135.htm</HtmlFileName>
      <LongName>134 - Disclosure - Financial Instruments (Details) - Schedule of contractual maturities of financial liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofcontractualmaturitiesoffinancialliabilitiesTable</Role>
      <ShortName>Financial Instruments (Details) - Schedule of contractual maturities of financial liabilities</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/FinancialInstrumentsTables</ParentRole>
      <Position>135</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R136.htm</HtmlFileName>
      <LongName>135 - Disclosure - Financial Instruments (Details) - Schedule of interest payable and interest payments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofinterestpayableandinterestpaymentsTable</Role>
      <ShortName>Financial Instruments (Details) - Schedule of interest payable and interest payments</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/FinancialInstrumentsTables</ParentRole>
      <Position>136</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R137.htm</HtmlFileName>
      <LongName>136 - Disclosure - Financial Instruments (Details) - Schedule of financial assets and financial liabilities and fair values hierarchy</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleoffinancialassetsandfinancialliabilitiesandfairvalueshierarchyTable</Role>
      <ShortName>Financial Instruments (Details) - Schedule of financial assets and financial liabilities and fair values hierarchy</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/FinancialInstrumentsTables</ParentRole>
      <Position>137</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R138.htm</HtmlFileName>
      <LongName>137 - Disclosure - Financial Instruments (Details) - Schedule of calculation of the fair value of the indebtednes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofcalculationofthefairvalueoftheindebtednesTable</Role>
      <ShortName>Financial Instruments (Details) - Schedule of calculation of the fair value of the indebtednes</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/FinancialInstrumentsTables</ParentRole>
      <Position>138</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R139.htm</HtmlFileName>
      <LongName>138 - Disclosure - Financial Instruments (Details) - Schedule of current and long-term portions of the fair value of the company???s derivative assets and liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofcurrentandlongtermportionsofthefairvalueofthecompanysderivativeassetsandliabilitiesTable</Role>
      <ShortName>Financial Instruments (Details) - Schedule of current and long-term portions of the fair value of the company???s derivative assets and liabilities</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/FinancialInstrumentsTables</ParentRole>
      <Position>139</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R140.htm</HtmlFileName>
      <LongName>139 - Disclosure - Financial Instruments (Details) - Schedule of reconciliation of fair value of derivative assets and liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofreconciliationoffairvalueofderivativeassetsandliabilitiesTable</Role>
      <ShortName>Financial Instruments (Details) - Schedule of reconciliation of fair value of derivative assets and liabilities</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/FinancialInstrumentsTables</ParentRole>
      <Position>140</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R141.htm</HtmlFileName>
      <LongName>140 - Disclosure - Share-Based Compensation Plans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ShareBasedCompensationPlansDetails</Role>
      <ShortName>Share-Based Compensation Plans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/ShareBasedCompensationPlansTables</ParentRole>
      <Position>141</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R142.htm</HtmlFileName>
      <LongName>141 - Disclosure - Share-Based Compensation Plans (Details) - Schedule of share-based compensation expense included in the consolidated statements of income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofsharebasedcompensationexpenseincludedintheconsolidatedstatementsofincomeTable</Role>
      <ShortName>Share-Based Compensation Plans (Details) - Schedule of share-based compensation expense included in the consolidated statements of income</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/ShareBasedCompensationPlansTables</ParentRole>
      <Position>142</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R143.htm</HtmlFileName>
      <LongName>142 - Disclosure - Share-Based Compensation Plans (Details) - Schedule of number of stock options outstanding and their weighted average exercise price</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofnumberofstockoptionsoutstandingandtheirweightedaverageexercisepriceTable</Role>
      <ShortName>Share-Based Compensation Plans (Details) - Schedule of number of stock options outstanding and their weighted average exercise price</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/ShareBasedCompensationPlansTables</ParentRole>
      <Position>143</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R144.htm</HtmlFileName>
      <LongName>143 - Disclosure - Share-Based Compensation Plans (Details) - Schedule of stock options that are exercisable and the weighted average remaining life</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofstockoptionsthatareexercisableandtheweightedaverageremaininglifeTable</Role>
      <ShortName>Share-Based Compensation Plans (Details) - Schedule of stock options that are exercisable and the weighted average remaining life</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/ShareBasedCompensationPlansTables</ParentRole>
      <Position>144</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R145.htm</HtmlFileName>
      <LongName>144 - Disclosure - Share-Based Compensation Plans (Details) - Schedule of share-based compensation expense for stock options using the Black-Scholes option pricing model</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofsharebasedcompensationexpenseforstockoptionsusingtheBlackScholesoptionpricingmodelTable</Role>
      <ShortName>Share-Based Compensation Plans (Details) - Schedule of share-based compensation expense for stock options using the Black-Scholes option pricing model</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/ShareBasedCompensationPlansTables</ParentRole>
      <Position>145</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R146.htm</HtmlFileName>
      <LongName>145 - Disclosure - Share-Based Compensation Plans (Details) - Schedule of number of restricted share units outstanding</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofnumberofrestrictedshareunitsoutstandingTable</Role>
      <ShortName>Share-Based Compensation Plans (Details) - Schedule of number of restricted share units outstanding</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/ShareBasedCompensationPlansTables</ParentRole>
      <Position>146</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R147.htm</HtmlFileName>
      <LongName>146 - Disclosure - Employee Benefit Plans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/EmployeeBenefitPlansDetails</Role>
      <ShortName>Employee Benefit Plans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/EmployeeBenefitPlansTables</ParentRole>
      <Position>147</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R148.htm</HtmlFileName>
      <LongName>147 - Disclosure - Employee Benefit Plans (Details) - Schedule of expenses included on consolidated statements of income and consolidated statements of comprehensive income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofexpensesincludedonconsolidatedstatementsofincomeandconsolidatedstatementsofcomprehensiveincomeTable</Role>
      <ShortName>Employee Benefit Plans (Details) - Schedule of expenses included on consolidated statements of income and consolidated statements of comprehensive income</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/EmployeeBenefitPlansTables</ParentRole>
      <Position>148</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R149.htm</HtmlFileName>
      <LongName>148 - Disclosure - Employee Benefit Plans (Details) - Schedule of balance sheet obligations, distributed between pension and other post-employment benefits</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofbalancesheetobligationsdistributedbetweenpensionandotherpostemploymentbenefitsTable</Role>
      <ShortName>Employee Benefit Plans (Details) - Schedule of balance sheet obligations, distributed between pension and other post-employment benefits</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/EmployeeBenefitPlansTables</ParentRole>
      <Position>149</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R150.htm</HtmlFileName>
      <LongName>149 - Disclosure - Employee Benefit Plans (Details) - Schedule of funded statuses of the benefit plans and accrued benefit liabilities balance</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleoffundedstatusesofthebenefitplansandaccruedbenefitliabilitiesbalanceTable</Role>
      <ShortName>Employee Benefit Plans (Details) - Schedule of funded statuses of the benefit plans and accrued benefit liabilities balance</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/EmployeeBenefitPlansTables</ParentRole>
      <Position>150</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R151.htm</HtmlFileName>
      <LongName>150 - Disclosure - Employee Benefit Plans (Details) - Schedule of changes in benefit obligations and fair value of plan assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofchangesinbenefitobligationsandfairvalueofplanassetsTable</Role>
      <ShortName>Employee Benefit Plans (Details) - Schedule of changes in benefit obligations and fair value of plan assets</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/EmployeeBenefitPlansTables</ParentRole>
      <Position>151</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R152.htm</HtmlFileName>
      <LongName>151 - Disclosure - Employee Benefit Plans (Details) - Schedule of estimated future benefit payments for defined benefit pension plans and other post-employment benefit plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofestimatedfuturebenefitpaymentsfordefinedbenefitpensionplansandotherpostemploymentbenefitplansTable</Role>
      <ShortName>Employee Benefit Plans (Details) - Schedule of estimated future benefit payments for defined benefit pension plans and other post-employment benefit plans</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/EmployeeBenefitPlansTables</ParentRole>
      <Position>152</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R153.htm</HtmlFileName>
      <LongName>152 - Disclosure - Employee Benefit Plans (Details) - Schedule of significant assumptions adopted in measuring pension and other benefit obligations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofsignificantassumptionsadoptedinmeasuringpensionandotherbenefitobligationsTable</Role>
      <ShortName>Employee Benefit Plans (Details) - Schedule of significant assumptions adopted in measuring pension and other benefit obligations</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/EmployeeBenefitPlansTables</ParentRole>
      <Position>153</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R154.htm</HtmlFileName>
      <LongName>153 - Disclosure - Employee Benefit Plans (Details) - Schedule of impact on defined benefit obligation from one percent increase or decrease change in assumptions used</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofimpactondefinedbenefitobligationfromonepercentincreaseordecreasechangeinassumptionsusedTable</Role>
      <ShortName>Employee Benefit Plans (Details) - Schedule of impact on defined benefit obligation from one percent increase or decrease change in assumptions used</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/EmployeeBenefitPlansTables</ParentRole>
      <Position>154</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R155.htm</HtmlFileName>
      <LongName>154 - Disclosure - Employee Benefit Plans (Details) - Schedule of other post-employment benefit plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofotherpostemploymentbenefitplansTable</Role>
      <ShortName>Employee Benefit Plans (Details) - Schedule of other post-employment benefit plans</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/EmployeeBenefitPlansTables</ParentRole>
      <Position>155</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R156.htm</HtmlFileName>
      <LongName>155 - Disclosure - Employee Benefit Plans (Details) - Schedule of impact on defined benefit obligation from one percent increase or decrease change in assumptions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofimpactondefinedbenefitobligationfromonepercentincreaseordecreasechangeinassumptionsTable</Role>
      <ShortName>Employee Benefit Plans (Details) - Schedule of impact on defined benefit obligation from one percent increase or decrease change in assumptions</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/EmployeeBenefitPlansTables</ParentRole>
      <Position>156</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R157.htm</HtmlFileName>
      <LongName>156 - Disclosure - Supplemental Cash Flow Information (Details) - Schedule of cash and cash equivalents</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofcashandcashequivalentsTable</Role>
      <ShortName>Supplemental Cash Flow Information (Details) - Schedule of cash and cash equivalents</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SupplementalCashFlowInformationTables</ParentRole>
      <Position>157</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R158.htm</HtmlFileName>
      <LongName>157 - Disclosure - Supplemental Cash Flow Information (Details) - Schedule of income taxes paid, net of income taxes received</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofincometaxespaidnetofincometaxesreceivedTable</Role>
      <ShortName>Supplemental Cash Flow Information (Details) - Schedule of income taxes paid, net of income taxes received</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SupplementalCashFlowInformationTables</ParentRole>
      <Position>158</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R159.htm</HtmlFileName>
      <LongName>158 - Disclosure - Supplemental Cash Flow Information (Details) - Schedule of Interest paid, net of interest received</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofInterestpaidnetofinterestreceivedTable</Role>
      <ShortName>Supplemental Cash Flow Information (Details) - Schedule of Interest paid, net of interest received</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SupplementalCashFlowInformationTables</ParentRole>
      <Position>159</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R160.htm</HtmlFileName>
      <LongName>159 - Disclosure - Supplemental Cash Flow Information (Details) - Schedule of reconciliation of the liabilities arising from financing activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofreconciliationoftheliabilitiesarisingfromfinancingactivitiesTable</Role>
      <ShortName>Supplemental Cash Flow Information (Details) - Schedule of reconciliation of the liabilities arising from financing activities</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SupplementalCashFlowInformationTables</ParentRole>
      <Position>160</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R161.htm</HtmlFileName>
      <LongName>160 - Disclosure - Supplemental Cash Flow Information (Details) - Schedule of net change in operating assets and liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofnetchangeinoperatingassetsandliabilitiesTable</Role>
      <ShortName>Supplemental Cash Flow Information (Details) - Schedule of net change in operating assets and liabilities</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SupplementalCashFlowInformationTables</ParentRole>
      <Position>161</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R162.htm</HtmlFileName>
      <LongName>161 - Disclosure - Supplemental Cash Flow Information (Details) - Schedule of non-cash investing activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofnoncashinvestingactivitiesTable</Role>
      <ShortName>Supplemental Cash Flow Information (Details) - Schedule of non-cash investing activities</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SupplementalCashFlowInformationTables</ParentRole>
      <Position>162</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R163.htm</HtmlFileName>
      <LongName>162 - Disclosure - Commitments and Contingent Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/CommitmentsandContingentLiabilitiesDetails</Role>
      <ShortName>Commitments and Contingent Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/CommitmentsandContingentLiabilitiesTables</ParentRole>
      <Position>163</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R164.htm</HtmlFileName>
      <LongName>163 - Disclosure - Commitments and Contingent Liabilities (Details) - Schedule of off-balance sheet contractual obligations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofoffbalancesheetcontractualobligationsTable</Role>
      <ShortName>Commitments and Contingent Liabilities (Details) - Schedule of off-balance sheet contractual obligations</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/CommitmentsandContingentLiabilitiesTables</ParentRole>
      <Position>164</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R165.htm</HtmlFileName>
      <LongName>164 - Disclosure - Subsidiaries (Details) - Schedule of companies included in scope of consolidation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofcompaniesincludedinscopeofconsolidationTable</Role>
      <ShortName>Subsidiaries (Details) - Schedule of companies included in scope of consolidation</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/SubsidiariesTables</ParentRole>
      <Position>165</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R166.htm</HtmlFileName>
      <LongName>165 - Disclosure - Related Party Transactions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/RelatedPartyTransactionsDetails</Role>
      <ShortName>Related Party Transactions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/RelatedPartyTransactionsTables</ParentRole>
      <Position>166</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R167.htm</HtmlFileName>
      <LongName>166 - Disclosure - Related Party Transactions (Details) - Schedule of compensation of executives and board level directors</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofcompensationofexecutivesandboardleveldirectorsTable</Role>
      <ShortName>Related Party Transactions (Details) - Schedule of compensation of executives and board level directors</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/RelatedPartyTransactionsTables</ParentRole>
      <Position>167</Position>
    </Report>
    <Report instance="f20f2021_telesat.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R168.htm</HtmlFileName>
      <LongName>167 - Disclosure - Related Party Transactions (Details) - Schedule of related parties transaction</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.telesat.com/role/ScheduleofrelatedpartiestransactionTable</Role>
      <ShortName>Related Party Transactions (Details) - Schedule of related parties transaction</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.telesat.com/role/RelatedPartyTransactionsTables</ParentRole>
      <Position>168</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="20-F" original="f20f2021_telesat.htm">f20f2021_telesat.htm</File>
    <File>f20f2021ex12-1_telesat.htm</File>
    <File>f20f2021ex12-2_telesat.htm</File>
    <File>f20f2021ex12-3_telesat.htm</File>
    <File>f20f2021ex12-4_telesat.htm</File>
    <File>f20f2021ex13-1_telesat.htm</File>
    <File>f20f2021ex13-2_telesat.htm</File>
    <File>f20f2021ex13-3_telesat.htm</File>
    <File>f20f2021ex13-4_telesat.htm</File>
    <File>f20f2021ex15-1_telesat.htm</File>
    <File>f20f2021ex2-6_telesat.htm</File>
    <File>f20f2021ex4-17_telesat.htm</File>
    <File>f20f2021ex8-1_telesat.htm</File>
    <File>tsat-20211231.xsd</File>
    <File>tsat-20211231_cal.xml</File>
    <File>tsat-20211231_def.xml</File>
    <File>tsat-20211231_lab.xml</File>
    <File>tsat-20211231_pre.xml</File>
  </InputFiles>
  <SupplementalFiles>
    <File>tdeliotte_header.jpg</File>
    <File>tflowchart_001.jpg</File>
    <File>tglobal_001.jpg</File>
    <File>timage_001.jpg</File>
    <File>tmap_001.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="1367">http://xbrl.ifrs.org/taxonomy/2021-03-24/ifrs-full</BaseTaxonomy>
    <BaseTaxonomy items="44">http://xbrl.sec.gov/dei/2021q4</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
