<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>312</ContextCount>
  <ElementCount>475</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>93</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>6</UnitCount>
  <MyReports>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001000 - Document - Document and Entity Information Document</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/DocumentAndEntityInformationDocument</Role>
      <ShortName>Document and Entity Information Document</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001000 - Statement - Statements of Condition</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/StatementsOfCondition</Role>
      <ShortName>Statements of Condition</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1001001 - Statement - Statements of Condition (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/StatementsOfConditionParenthetical</Role>
      <ShortName>Statements of Condition (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1002000 - Statement - Statements of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/StatementsOfIncome</Role>
      <ShortName>Statements of Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1003000 - Statement - Statements of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/StatementsOfComprehensiveIncome</Role>
      <ShortName>Statements of Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1004000 - Statement - Statements of Capital</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/StatementsOfCapital</Role>
      <ShortName>Statements of Capital</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1005000 - Statement - Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/StatementsOfCashFlows</Role>
      <ShortName>Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>2101100 - Disclosure - Background Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/BackgroundInformation</Role>
      <ShortName>Background Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2102100 - Disclosure - Basis of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/BasisOfPresentation</Role>
      <ShortName>Basis of Presentation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2105100 - Disclosure - Recently Adopted and Issued Accounting Guidance</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/RecentlyAdoptedAndIssuedAccountingGuidance</Role>
      <ShortName>Recently Adopted and Issued Accounting Guidance</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2107100 - Disclosure - Investments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/Investments</Role>
      <ShortName>Investments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2110100 - Disclosure - Advances</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/Advances</Role>
      <ShortName>Advances</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2111100 - Disclosure - Mortgage Loans Held for Portfolio</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/MortgageLoansHeldForPortfolio</Role>
      <ShortName>Mortgage Loans Held for Portfolio</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2114100 - Disclosure - Derivatives and Hedging Activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/DerivativesAndHedgingActivities</Role>
      <ShortName>Derivatives and Hedging Activities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2117100 - Disclosure - Consolidated Obligations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/ConsolidatedObligations</Role>
      <ShortName>Consolidated Obligations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2119100 - Disclosure - Capital</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/Capital</Role>
      <ShortName>Capital</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2120100 - Disclosure - Fair Value</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/FairValue</Role>
      <ShortName>Fair Value</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2121100 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/CommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2122100 - Disclosure - Activities with Stockholders</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/ActivitiesWithStockholders</Role>
      <ShortName>Activities with Stockholders</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2123100 - Disclosure - Activities with Other FHLBanks</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/ActivitiesWithOtherFhlbanks</Role>
      <ShortName>Activities with Other FHLBanks</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2124100 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/SubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2202201 - Disclosure - Basis of Presentation (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/BasisOfPresentationPolicies</Role>
      <ShortName>Basis of Presentation (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/RecentlyAdoptedAndIssuedAccountingGuidance</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2307301 - Disclosure - Investments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/InvestmentsTables</Role>
      <ShortName>Investments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/Investments</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2310301 - Disclosure - Advances (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/AdvancesTables</Role>
      <ShortName>Advances (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/Advances</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2311301 - Disclosure - Mortgage Loans Held for Portfolio (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/MortgageLoansHeldForPortfolioTables</Role>
      <ShortName>Mortgage Loans Held for Portfolio (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/MortgageLoansHeldForPortfolio</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2314301 - Disclosure - Derivatives and Hedging Activities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/DerivativesAndHedgingActivitiesTables</Role>
      <ShortName>Derivatives and Hedging Activities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/DerivativesAndHedgingActivities</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2317301 - Disclosure - Consolidated Obligations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/ConsolidatedObligationsTables</Role>
      <ShortName>Consolidated Obligations (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/ConsolidatedObligations</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2319301 - Disclosure - Capital (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/CapitalTables</Role>
      <ShortName>Capital (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/Capital</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2320301 - Disclosure - Fair Value (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/FairValueTables</Role>
      <ShortName>Fair Value (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/FairValue</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2321301 - Disclosure - Commitments and Contingencies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/CommitmentsAndContingenciesTables</Role>
      <ShortName>Commitments and Contingencies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/CommitmentsAndContingencies</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2322301 - Disclosure - Activities with Stockholders (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/ActivitiesWithStockholdersTables</Role>
      <ShortName>Activities with Stockholders (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/ActivitiesWithStockholders</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2323301 - Disclosure - Activities with Other FHLBanks (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/ActivitiesWithOtherFhlbanksTables</Role>
      <ShortName>Activities with Other FHLBanks (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/ActivitiesWithOtherFhlbanks</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2401401 - Disclosure - Background Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/BackgroundInformationDetails</Role>
      <ShortName>Background Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/BackgroundInformation</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2407402 - Disclosure - Investments (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/InvestmentsNarrativeDetails</Role>
      <ShortName>Investments (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/InvestmentsTables</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2407403 - Disclosure - Investments (Trading Major Security Types) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/InvestmentsTradingMajorSecurityTypesDetails</Role>
      <ShortName>Investments (Trading Major Security Types) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/InvestmentsTables</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2407404 - Disclosure - Investments (AFS Major Security Types) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/InvestmentsAfsMajorSecurityTypesDetails</Role>
      <ShortName>Investments (AFS Major Security Types) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/InvestmentsTables</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2407405 - Disclosure - Investments (AFS Unrealized Losses) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/InvestmentsAfsUnrealizedLossesDetails</Role>
      <ShortName>Investments (AFS Unrealized Losses) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/InvestmentsTables</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2407406 - Disclosure - Investments (AFS Contractual Maturity) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/InvestmentsAfsContractualMaturityDetails</Role>
      <ShortName>Investments (AFS Contractual Maturity) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/InvestmentsTables</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2407407 - Disclosure - Investments (HTM Major Security Types) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/InvestmentsHtmMajorSecurityTypesDetails</Role>
      <ShortName>Investments (HTM Major Security Types) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/InvestmentsTables</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2407408 - Disclosure - Investments (HTM Contractual Maturity) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/InvestmentsHtmContractualMaturityDetails</Role>
      <ShortName>Investments (HTM Contractual Maturity) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/InvestmentsTables</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2407409 - Disclosure - Investments (Sales of Securities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/InvestmentsSalesOfSecuritiesDetails</Role>
      <ShortName>Investments (Sales of Securities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/InvestmentsTables</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2410402 - Disclosure - Advances (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/AdvancesNarrativeDetails</Role>
      <ShortName>Advances (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/AdvancesTables</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2410403 - Disclosure - Advances (Redemption Terms) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/AdvancesRedemptionTermsDetails</Role>
      <ShortName>Advances (Redemption Terms) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/AdvancesTables</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2410404 - Disclosure - Advances (Prepayment Fees) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/AdvancesPrepaymentFeesDetails</Role>
      <ShortName>Advances (Prepayment Fees) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/AdvancesTables</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2411402 - Disclosure - Mortgage Loans Held for Portfolio (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/MortgageLoansHeldForPortfolioNarrativeDetails</Role>
      <ShortName>Mortgage Loans Held for Portfolio (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/MortgageLoansHeldForPortfolioTables</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2411403 - Disclosure - Mortgage Loans Held for Portfolio (Mortgage Loans Held for Portfolio) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/MortgageLoansHeldForPortfolioMortgageLoansHeldForPortfolioDetails</Role>
      <ShortName>Mortgage Loans Held for Portfolio (Mortgage Loans Held for Portfolio) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/MortgageLoansHeldForPortfolioTables</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2411404 - Disclosure - Mortgage Loans Held for Portfolio (Mortgage Loans Held for Portfolio by Collateral or Guarantee Type) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/MortgageLoansHeldForPortfolioMortgageLoansHeldForPortfolioByCollateralOrGuaranteeTypeDetails</Role>
      <ShortName>Mortgage Loans Held for Portfolio (Mortgage Loans Held for Portfolio by Collateral or Guarantee Type) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/MortgageLoansHeldForPortfolioTables</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2411405 - Disclosure - Mortgage Loans Held for Portfolio (Payment Status) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/MortgageLoansHeldForPortfolioPaymentStatusDetails</Role>
      <ShortName>Mortgage Loans Held for Portfolio (Payment Status) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/MortgageLoansHeldForPortfolioTables</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2411406 - Disclosure - Mortgage Loans Held for Portfolio (Other Delinquency Statistics) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/MortgageLoansHeldForPortfolioOtherDelinquencyStatisticsDetails</Role>
      <ShortName>Mortgage Loans Held for Portfolio (Other Delinquency Statistics) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/MortgageLoansHeldForPortfolioTables</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2414402 - Disclosure - Derivatives and Hedging Activities (Derivatives in Statement of Condition) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/DerivativesAndHedgingActivitiesDerivativesInStatementOfConditionDetails</Role>
      <ShortName>Derivatives and Hedging Activities (Derivatives in Statement of Condition) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/DerivativesAndHedgingActivitiesTables</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2414403 - Disclosure - Derivatives and Hedging Activities Net Gains (Losses) on Fair Value Hedging Relationships (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/DerivativesAndHedgingActivitiesNetGainsLossesOnFairValueHedgingRelationshipsDetails</Role>
      <ShortName>Derivatives and Hedging Activities Net Gains (Losses) on Fair Value Hedging Relationships (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2414404 - Disclosure - Derivatives and Hedging Activities Cumulative Basis Adjustments for Fair Value Hedges (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/DerivativesAndHedgingActivitiesCumulativeBasisAdjustmentsForFairValueHedgesDetails</Role>
      <ShortName>Derivatives and Hedging Activities Cumulative Basis Adjustments for Fair Value Hedges (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2414405 - Disclosure - Derivatives and Hedging Activities (Derivatives in Statement of Income) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/DerivativesAndHedgingActivitiesDerivativesInStatementOfIncomeDetails</Role>
      <ShortName>Derivatives and Hedging Activities (Derivatives in Statement of Income) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/DerivativesAndHedgingActivitiesTables</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2414406 - Disclosure - Derivatives and Hedging Activities (Credit Risk Exposure) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/DerivativesAndHedgingActivitiesCreditRiskExposureDetails</Role>
      <ShortName>Derivatives and Hedging Activities (Credit Risk Exposure) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/DerivativesAndHedgingActivitiesTables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2414407 - Disclosure - Derivatives and Hedging Activities (Offsetting of Derivative Assets and Derivative Liabilities) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/DerivativesAndHedgingActivitiesOffsettingOfDerivativeAssetsAndDerivativeLiabilitiesDetails</Role>
      <ShortName>Derivatives and Hedging Activities (Offsetting of Derivative Assets and Derivative Liabilities) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/DerivativesAndHedgingActivitiesTables</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2417402 - Disclosure - Consolidated Obligations Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/ConsolidatedObligationsNarrativeDetails</Role>
      <ShortName>Consolidated Obligations Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2417403 - Disclosure - Consolidated Obligations Discount Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.fhlbdm.com/role/ConsolidatedObligationsDiscountNotesDetails</Role>
      <ShortName>Consolidated Obligations Discount Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>2417404 - Disclosure - Consolidated Obligations Bonds (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/ConsolidatedObligationsBondsDetails</Role>
      <ShortName>Consolidated Obligations Bonds (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/ConsolidatedObligationsTables</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>2417405 - Disclosure - Consolidated Obligations Bonds by Call Features (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/ConsolidatedObligationsBondsByCallFeaturesDetails</Role>
      <ShortName>Consolidated Obligations Bonds by Call Features (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>2419402 - Disclosure - Capital (Narrative) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/CapitalNarrativeDetails</Role>
      <ShortName>Capital (Narrative) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/CapitalTables</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>2419403 - Disclosure - Capital (Rollforward of MRCS) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/CapitalRollforwardOfMrcsDetails</Role>
      <ShortName>Capital (Rollforward of MRCS) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/CapitalTables</ParentRole>
      <Position>61</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>2419404 - Disclosure - Capital (Mandatorily Redeemable Capital Stock) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/CapitalMandatorilyRedeemableCapitalStockDetails</Role>
      <ShortName>Capital (Mandatorily Redeemable Capital Stock) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/CapitalTables</ParentRole>
      <Position>62</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>2419405 - Disclosure - Capital (Accumulated Other Comprehensive Income) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/CapitalAccumulatedOtherComprehensiveIncomeDetails</Role>
      <ShortName>Capital (Accumulated Other Comprehensive Income) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/CapitalTables</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>2419406 - Disclosure - Capital (Regulatory Capital Requirements) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/CapitalRegulatoryCapitalRequirementsDetails</Role>
      <ShortName>Capital (Regulatory Capital Requirements) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/CapitalTables</ParentRole>
      <Position>64</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>2419407 - Disclosure - Capital Retained Earnings (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/CapitalRetainedEarningsDetails</Role>
      <ShortName>Capital Retained Earnings (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>2420402 - Disclosure - Fair Value (Carrying Value and Fair Value of Financial Instruments) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/FairValueCarryingValueAndFairValueOfFinancialInstrumentsDetails</Role>
      <ShortName>Fair Value (Carrying Value and Fair Value of Financial Instruments) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/FairValueTables</ParentRole>
      <Position>66</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>2420403 - Disclosure - Fair Value (Fair Value on a Recurring Basis) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/FairValueFairValueOnRecurringBasisDetails</Role>
      <ShortName>Fair Value (Fair Value on a Recurring Basis) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/FairValueTables</ParentRole>
      <Position>67</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>2420404 - Disclosure - Fair Value (Fair Value on a Non-Recurring Basis) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/FairValueFairValueOnNonRecurringBasisDetails</Role>
      <ShortName>Fair Value (Fair Value on a Non-Recurring Basis) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/FairValueTables</ParentRole>
      <Position>68</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>2421402 - Disclosure - Commitments and Contingencies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/CommitmentsAndContingenciesDetails</Role>
      <ShortName>Commitments and Contingencies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/CommitmentsAndContingenciesTables</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>2422402 - Disclosure - Activities with Stockholders (Transactions with Directors' Financial Institutions) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/ActivitiesWithStockholdersTransactionsWithDirectorsFinancialInstitutionsDetails</Role>
      <ShortName>Activities with Stockholders (Transactions with Directors' Financial Institutions) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/ActivitiesWithStockholdersTables</ParentRole>
      <Position>70</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>2422403 - Disclosure - Activities with Stockholders (Business Concentrations) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/ActivitiesWithStockholdersBusinessConcentrationsDetails</Role>
      <ShortName>Activities with Stockholders (Business Concentrations) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/ActivitiesWithStockholdersTables</ParentRole>
      <Position>71</Position>
    </Report>
    <Report instance="fhlb03312010q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>2423402 - Disclosure - Activities with Other FHLBanks (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbdm.com/role/ActivitiesWithOtherFhlbanksDetails</Role>
      <ShortName>Activities with Other FHLBanks (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbdm.com/role/ActivitiesWithOtherFhlbanksTables</ParentRole>
      <Position>72</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-Q" original="fhlb03312010q.htm">fhlb03312010q.htm</File>
    <File>exhibit311certificatio.htm</File>
    <File>exhibit312certificatio.htm</File>
    <File>exhibit321certificatio.htm</File>
    <File>exhibit322certificatio.htm</File>
    <File>fhlbdm-20200331.xsd</File>
    <File>fhlbdm-20200331_cal.xml</File>
    <File>fhlbdm-20200331_def.xml</File>
    <File>fhlbdm-20200331_lab.xml</File>
    <File>fhlbdm-20200331_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/srt/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2020-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
