<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.24.1.u1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>350</ContextCount>
  <ElementCount>414</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>91</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>6</UnitCount>
  <MyReports>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Document and Entity Information Document</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/DocumentandEntityInformationDocument</Role>
      <ShortName>Document and Entity Information Document</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>0000002 - Statement - Statements of Condition</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/StatementsofCondition</Role>
      <ShortName>Statements of Condition</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>0000003 - Statement - Statements of Condition (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/StatementsofConditionParenthetical</Role>
      <ShortName>Statements of Condition (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>0000004 - Statement - Statements of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/StatementsofIncome</Role>
      <ShortName>Statements of Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>0000005 - Statement - Statements of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/StatementsofComprehensiveIncome</Role>
      <ShortName>Statements of Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>0000006 - Statement - Statements of Capital</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/StatementsofCapital</Role>
      <ShortName>Statements of Capital</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>0000007 - Statement - Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/StatementsofCashFlows</Role>
      <ShortName>Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>0000008 - Disclosure - Background Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/BackgroundInformation</Role>
      <ShortName>Background Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>0000009 - Disclosure - Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AccountingPolicies</Role>
      <ShortName>Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>0000010 - Disclosure - Recently Issued Accounting Standards and Interpretations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/RecentlyIssuedAccountingStandardsandInterpretations</Role>
      <ShortName>Recently Issued Accounting Standards and Interpretations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>0000011 - Disclosure - Investments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/Investments</Role>
      <ShortName>Investments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>0000012 - Disclosure - Advances</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/Advances</Role>
      <ShortName>Advances</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>0000013 - Disclosure - Mortgage Loans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/MortgageLoans</Role>
      <ShortName>Mortgage Loans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>0000014 - Disclosure - Derivatives and Hedging Activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/DerivativesandHedgingActivities</Role>
      <ShortName>Derivatives and Hedging Activities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>0000015 - Disclosure - Consolidated Obligations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/ConsolidatedObligations</Role>
      <ShortName>Consolidated Obligations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>0000016 - Disclosure - Affordable Housing Program (AHP)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AffordableHousingProgramAHP</Role>
      <ShortName>Affordable Housing Program (AHP)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>0000017 - Disclosure - Capital</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/Capital</Role>
      <ShortName>Capital</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>0000018 - Disclosure - Accumulated Other Comprehensive (Loss) Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AccumulatedOtherComprehensiveLossIncome</Role>
      <ShortName>Accumulated Other Comprehensive (Loss) Income</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>0000019 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/SegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>0000020 - Disclosure - Fair Value Disclosures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/FairValueDisclosures</Role>
      <ShortName>Fair Value Disclosures</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>0000021 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/CommitmentsandContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>0000022 - Disclosure - Transactions with Other FHLBanks</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/TransactionswithOtherFHLBanks</Role>
      <ShortName>Transactions with Other FHLBanks</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>0000023 - Disclosure - Transactions with Stockholders</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/TransactionswithStockholders</Role>
      <ShortName>Transactions with Stockholders</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>9954471 - Disclosure - Recently Issued Accounting Standards and Interpretations (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/RecentlyIssuedAccountingStandardsandInterpretationsPolicies</Role>
      <ShortName>Recently Issued Accounting Standards and Interpretations (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/AccountingPolicies</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>9954472 - Disclosure - Investments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/InvestmentsTables</Role>
      <ShortName>Investments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/Investments</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>9954473 - Disclosure - Advances Advances (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AdvancesAdvancesTables</Role>
      <ShortName>Advances Advances (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>9954474 - Disclosure - Mortgage Loans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/MortgageLoansTables</Role>
      <ShortName>Mortgage Loans (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/MortgageLoans</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>9954475 - Disclosure - Derivatives and Hedging Activities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/DerivativesandHedgingActivitiesTables</Role>
      <ShortName>Derivatives and Hedging Activities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/DerivativesandHedgingActivities</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>9954476 - Disclosure - Consolidated Obligations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/ConsolidatedObligationsTables</Role>
      <ShortName>Consolidated Obligations (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/ConsolidatedObligations</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>9954477 - Disclosure - Affordable Housing Program (AHP) (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AffordableHousingProgramAHPTables</Role>
      <ShortName>Affordable Housing Program (AHP) (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/AffordableHousingProgramAHP</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>9954478 - Disclosure - Capital (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/CapitalTables</Role>
      <ShortName>Capital (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/Capital</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>9954479 - Disclosure - Accumulated Other Comprehensive (Loss) Income (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AccumulatedOtherComprehensiveLossIncomeTables</Role>
      <ShortName>Accumulated Other Comprehensive (Loss) Income (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/AccumulatedOtherComprehensiveLossIncome</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>9954480 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/SegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/SegmentInformation</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>9954481 - Disclosure - Fair Value Disclosures Fair Value (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/FairValueDisclosuresFairValueTables</Role>
      <ShortName>Fair Value Disclosures Fair Value (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>9954482 - Disclosure - Commitments and Contingencies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/CommitmentsandContingenciesTables</Role>
      <ShortName>Commitments and Contingencies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/CommitmentsandContingencies</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>9954483 - Disclosure - Transactions with Other FHLBanks (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/TransactionswithOtherFHLBanksTables</Role>
      <ShortName>Transactions with Other FHLBanks (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/TransactionswithOtherFHLBanks</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>9954484 - Disclosure - Transactions with Stockholders (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/TransactionswithStockholdersTables</Role>
      <ShortName>Transactions with Stockholders (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/TransactionswithStockholders</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>9954485 - Disclosure - Background Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/BackgroundInformationDetails</Role>
      <ShortName>Background Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/BackgroundInformation</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>9954486 - Disclosure - Investments Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/InvestmentsNarrativeDetails</Role>
      <ShortName>Investments Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>9954487 - Disclosure - Investments Trading Securities by Major Security Type (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/InvestmentsTradingSecuritiesbyMajorSecurityTypeDetails</Role>
      <ShortName>Investments Trading Securities by Major Security Type (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>9954488 - Disclosure - Investments Trading Securities Net Gains (Losses) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/InvestmentsTradingSecuritiesNetGainsLossesDetails</Role>
      <ShortName>Investments Trading Securities Net Gains (Losses) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>9954489 - Disclosure - Investments AFS Securities by Major Security Type (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/InvestmentsAFSSecuritiesbyMajorSecurityTypeDetails</Role>
      <ShortName>Investments AFS Securities by Major Security Type (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>9954490 - Disclosure - Investments AFS Securities in a Continuous Unrealized Loss Position (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/InvestmentsAFSSecuritiesinaContinuousUnrealizedLossPositionDetails</Role>
      <ShortName>Investments AFS Securities in a Continuous Unrealized Loss Position (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>9954491 - Disclosure - Investments AFS Securities by Contractual Maturity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/InvestmentsAFSSecuritiesbyContractualMaturityDetails</Role>
      <ShortName>Investments AFS Securities by Contractual Maturity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>9954492 - Disclosure - Investments AFS Securities by Interest Rate Payment Terms (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/InvestmentsAFSSecuritiesbyInterestRatePaymentTermsDetails</Role>
      <ShortName>Investments AFS Securities by Interest Rate Payment Terms (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>9954493 - Disclosure - Investments HTM Securities by Major Security Type (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/InvestmentsHTMSecuritiesbyMajorSecurityTypeDetails</Role>
      <ShortName>Investments HTM Securities by Major Security Type (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>9954494 - Disclosure - Investments HTM Securitites by Contractual Maturity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/InvestmentsHTMSecurititesbyContractualMaturityDetails</Role>
      <ShortName>Investments HTM Securitites by Contractual Maturity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>9954495 - Disclosure - Investments HTM Securities by Interest Rate Payment Terms (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/InvestmentsHTMSecuritiesbyInterestRatePaymentTermsDetails</Role>
      <ShortName>Investments HTM Securities by Interest Rate Payment Terms (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>9954496 - Disclosure - Advances Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AdvancesNarrativeDetails</Role>
      <ShortName>Advances Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>9954497 - Disclosure - Advances (Advance Redemption Terms) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AdvancesAdvanceRedemptionTermsDetails</Role>
      <ShortName>Advances (Advance Redemption Terms) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/AdvancesAdvancesTables</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>9954498 - Disclosure - Advances (Year of Contractual Maturity or Next Call Date) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AdvancesYearofContractualMaturityorNextCallDateDetails</Role>
      <ShortName>Advances (Year of Contractual Maturity or Next Call Date) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/AdvancesAdvancesTables</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>9954499 - Disclosure - Advances (Advances by Year of Contractual Maturity or Next Put/Convert Date for Putable/Convertible Advances) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AdvancesAdvancesbyYearofContractualMaturityorNextPutConvertDateforPutableConvertibleAdvancesDetails</Role>
      <ShortName>Advances (Advances by Year of Contractual Maturity or Next Put/Convert Date for Putable/Convertible Advances) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/AdvancesAdvancesTables</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>9954500 - Disclosure - Advances (Advances by Interest Rate Payment Terms) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AdvancesAdvancesbyInterestRatePaymentTermsDetails</Role>
      <ShortName>Advances (Advances by Interest Rate Payment Terms) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/AdvancesAdvancesTables</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>9954501 - Disclosure - Advances (Borrowers Holding Five Percent or more of Total Advances) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AdvancesBorrowersHoldingFivePercentormoreofTotalAdvancesDetails</Role>
      <ShortName>Advances (Borrowers Holding Five Percent or more of Total Advances) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/AdvancesAdvancesTables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>9954502 - Disclosure - Mortgage Loans Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/MortgageLoansNarrativeDetails</Role>
      <ShortName>Mortgage Loans Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>9954503 - Disclosure - Mortgage Loans Mortgage Loans Held for Portfolio (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/MortgageLoansMortgageLoansHeldforPortfolioDetails</Role>
      <ShortName>Mortgage Loans Mortgage Loans Held for Portfolio (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>9954504 - Disclosure - Mortgage Loans Members with Five Percent or More of Mortgage Loans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/MortgageLoansMemberswithFivePercentorMoreofMortgageLoansDetails</Role>
      <ShortName>Mortgage Loans Members with Five Percent or More of Mortgage Loans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>9954505 - Disclosure - Mortgage Loans Mortgage Loans Rollforward of LRA (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/MortgageLoansMortgageLoansRollforwardofLRADetails</Role>
      <ShortName>Mortgage Loans Mortgage Loans Rollforward of LRA (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>9954506 - Disclosure - Mortgage Loans Mortgage Loans Past Due (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/MortgageLoansMortgageLoansPastDueDetails</Role>
      <ShortName>Mortgage Loans Mortgage Loans Past Due (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>9954507 - Disclosure - Mortgage Loans Mortgage Loans Other Delinquency Status (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/MortgageLoansMortgageLoansOtherDelinquencyStatusDetails</Role>
      <ShortName>Mortgage Loans Mortgage Loans Other Delinquency Status (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>9954508 - Disclosure - Derivatives and Hedging Activities Derivatives in Statement of Condition (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/DerivativesandHedgingActivitiesDerivativesinStatementofConditionDetails</Role>
      <ShortName>Derivatives and Hedging Activities Derivatives in Statement of Condition (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>9954509 - Disclosure - Derivatives and Hedging Activities Derivatives in Statement of Income and Impact on Interest (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/DerivativesandHedgingActivitiesDerivativesinStatementofIncomeandImpactonInterestDetails</Role>
      <ShortName>Derivatives and Hedging Activities Derivatives in Statement of Income and Impact on Interest (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>9954510 - Disclosure - Derivatives and Hedging Activities Derivative Fair Value Hedges (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/DerivativesandHedgingActivitiesDerivativeFairValueHedgesDetails</Role>
      <ShortName>Derivatives and Hedging Activities Derivative Fair Value Hedges (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>9954511 - Disclosure - Derivatives and Hedging Activities Derivatives in Statement of Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/DerivativesandHedgingActivitiesDerivativesinStatementofIncomeDetails</Role>
      <ShortName>Derivatives and Hedging Activities Derivatives in Statement of Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>9954512 - Disclosure - Derivatives and Hedging Activities Offsetting of Derivative Assets and Derivative Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/DerivativesandHedgingActivitiesOffsettingofDerivativeAssetsandDerivativeLiabilitiesDetails</Role>
      <ShortName>Derivatives and Hedging Activities Offsetting of Derivative Assets and Derivative Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>9954513 - Disclosure - Consolidated Obligations Discount Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.fhlbcin.com/role/ConsolidatedObligationsDiscountNotesDetails</Role>
      <ShortName>Consolidated Obligations Discount Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>9954514 - Disclosure - Consolidated Obligations Bonds by Original Contractual Maturity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/ConsolidatedObligationsBondsbyOriginalContractualMaturityDetails</Role>
      <ShortName>Consolidated Obligations Bonds by Original Contractual Maturity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>9954515 - Disclosure - Consolidated Obligations Bonds by Call Feature (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/ConsolidatedObligationsBondsbyCallFeatureDetails</Role>
      <ShortName>Consolidated Obligations Bonds by Call Feature (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>9954516 - Disclosure - Consolidated Obligations Bonds by Contractual Maturity or Next Call Date (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/ConsolidatedObligationsBondsbyContractualMaturityorNextCallDateDetails</Role>
      <ShortName>Consolidated Obligations Bonds by Contractual Maturity or Next Call Date (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>9954517 - Disclosure - Consolidated Obligations Bonds by Interest-Rate Type (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/ConsolidatedObligationsBondsbyInterestRateTypeDetails</Role>
      <ShortName>Consolidated Obligations Bonds by Interest-Rate Type (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>9954518 - Disclosure - Affordable Housing Program (AHP) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AffordableHousingProgramAHPDetails</Role>
      <ShortName>Affordable Housing Program (AHP) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/AffordableHousingProgramAHPTables</ParentRole>
      <Position>71</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>9954519 - Disclosure - Capital Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/CapitalNarrativeDetails</Role>
      <ShortName>Capital Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>9954520 - Disclosure - Capital (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/CapitalDetails</Role>
      <ShortName>Capital (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/CapitalTables</ParentRole>
      <Position>73</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>9954521 - Disclosure - Capital (Mandatorily Redeemable Capital Stock) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/CapitalMandatorilyRedeemableCapitalStockDetails</Role>
      <ShortName>Capital (Mandatorily Redeemable Capital Stock) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/CapitalTables</ParentRole>
      <Position>74</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>9954522 - Disclosure - Capital (Mandatorily Redeemable Capital Stock by Contractual Year of Redemption) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/CapitalMandatorilyRedeemableCapitalStockbyContractualYearofRedemptionDetails</Role>
      <ShortName>Capital (Mandatorily Redeemable Capital Stock by Contractual Year of Redemption) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/CapitalTables</ParentRole>
      <Position>75</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>9954523 - Disclosure - Accumulated Other Comprehensive (Loss) Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/AccumulatedOtherComprehensiveLossIncomeDetails</Role>
      <ShortName>Accumulated Other Comprehensive (Loss) Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/AccumulatedOtherComprehensiveLossIncomeTables</ParentRole>
      <Position>76</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>9954524 - Disclosure - Segment Information Financial Performance (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/SegmentInformationFinancialPerformanceDetails</Role>
      <ShortName>Segment Information Financial Performance (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>9954525 - Disclosure - Segment Information Asset Balances (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/SegmentInformationAssetBalancesDetails</Role>
      <ShortName>Segment Information Asset Balances (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>9954526 - Disclosure - Fair Value Disclosures Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/FairValueDisclosuresNarrativeDetails</Role>
      <ShortName>Fair Value Disclosures Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>9954527 - Disclosure - Fair Value Disclosures Fair Value Summary (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/FairValueDisclosuresFairValueSummaryDetails</Role>
      <ShortName>Fair Value Disclosures Fair Value Summary (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/FairValueDisclosuresFairValueTables</ParentRole>
      <Position>80</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>9954528 - Disclosure - Fair Value Disclosures Fair Value Measured on a Recurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/FairValueDisclosuresFairValueMeasuredonaRecurringBasisDetails</Role>
      <ShortName>Fair Value Disclosures Fair Value Measured on a Recurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>81</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>9954529 - Disclosure - Fair Value Disclosures Fair Value Impact on Financial Performance (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/FairValueDisclosuresFairValueImpactonFinancialPerformanceDetails</Role>
      <ShortName>Fair Value Disclosures Fair Value Impact on Financial Performance (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>9954530 - Disclosure - Fair Value Disclosures Fair Value Difference Between Fair Value and Remaining Contractual Principal Balance Outstanding (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/FairValueDisclosuresFairValueDifferenceBetweenFairValueandRemainingContractualPrincipalBalanceOutstandingDetails</Role>
      <ShortName>Fair Value Disclosures Fair Value Difference Between Fair Value and Remaining Contractual Principal Balance Outstanding (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>83</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>9954531 - Disclosure - Commitments and Contingencies Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/CommitmentsandContingenciesNarrativeDetails</Role>
      <ShortName>Commitments and Contingencies Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>84</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>9954532 - Disclosure - Commitments and Contingencies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/CommitmentsandContingenciesDetails</Role>
      <ShortName>Commitments and Contingencies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/CommitmentsandContingenciesTables</ParentRole>
      <Position>85</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>9954533 - Disclosure - Transactions with Other FHLBanks (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/TransactionswithOtherFHLBanksDetails</Role>
      <ShortName>Transactions with Other FHLBanks (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/TransactionswithOtherFHLBanksTables</ParentRole>
      <Position>86</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>9954534 - Disclosure - Transactions with Stockholders (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/TransactionswithStockholdersDetails</Role>
      <ShortName>Transactions with Stockholders (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/TransactionswithStockholdersTables</ParentRole>
      <Position>87</Position>
    </Report>
    <Report instance="fhlbcin-20240331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>9954535 - Disclosure - Transactions with Stockholders (Concentrations) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.fhlbcin.com/role/TransactionswithStockholdersConcentrationsDetails</Role>
      <ShortName>Transactions with Stockholders (Concentrations) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.fhlbcin.com/role/TransactionswithStockholdersTables</ParentRole>
      <Position>88</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <Logs>
    <Log type="Warning">[ix-0514-Hidden-Fact-Not-Referenced] WARN: 22 fact(s) appearing in ix:hidden were not referenced by any -sec-ix-hidden style property: us-gaap:DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleList, us-gaap:DebtSecuritiesAvailableForSaleRestrictionTypeExtensibleList, us-gaap:DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleList, us-gaap:FinancialAssetAmortizedCostAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleList, us-gaap:FinancingReceivableAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleList, us-gaap:HedgedAssetStatementOfFinancialPositionExtensibleEnumeration, us-gaap:HedgedLiabilityStatementOfFinancialPositionExtensibleEnumeration -  fhlbcin-20240331.htm 4</Log>
  </Logs>
  <InputFiles>
    <File doctype="10-Q" isDefinitelyFs="true" isUsgaap="true" original="fhlbcin-20240331.htm">fhlbcin-20240331.htm</File>
    <File>fhlbcin-20240331.xsd</File>
    <File>fhlbcin-20240331_cal.xml</File>
    <File>fhlbcin-20240331_def.xml</File>
    <File>fhlbcin-20240331_lab.xml</File>
    <File>fhlbcin-20240331_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="1533">http://fasb.org/us-gaap/2023</BaseTaxonomy>
    <BaseTaxonomy items="26">http://xbrl.sec.gov/dei/2023</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
