<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>1454</ContextCount>
  <ElementCount>374</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>118</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>7</UnitCount>
  <MyReports>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>75000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>75010 - Statement - Consolidated Statements of Assets and Liabilities (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/StatementConsolidatedStatementsOfAssetsAndLiabilitiesUnaudited</Role>
      <ShortName>Consolidated Statements of Assets and Liabilities (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>75020 - Statement - Consolidated Statements of Assets and Liabilities (Parenthetical) (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/StatementConsolidatedStatementsOfAssetsAndLiabilitiesParentheticalUnaudited</Role>
      <ShortName>Consolidated Statements of Assets and Liabilities (Parenthetical) (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>75030 - Statement - Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/StatementConsolidatedStatementsOfOperations</Role>
      <ShortName>Consolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>75040 - Statement - Consolidated Statements of Changes in Net Assets (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/StatementConsolidatedStatementsOfChangesInNetAssetsUnaudited</Role>
      <ShortName>Consolidated Statements of Changes in Net Assets (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>75050 - Statement - Consolidated Statement of Changes in Net Assets (Unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/StatementConsolidatedStatementOfChangesInNetAssetsUnauditedParenthetical</Role>
      <ShortName>Consolidated Statement of Changes in Net Assets (Unaudited) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>75060 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/StatementConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>75070 - Statement - Consolidated Statements of Cash Flows (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/StatementConsolidatedStatementsOfCashFlowsParenthetical</Role>
      <ShortName>Consolidated Statements of Cash Flows (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>75080 - Statement - Consolidated Schedule of Investments (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/StatementConsolidatedScheduleOfInvestmentsUnaudited1</Role>
      <ShortName>Consolidated Schedule of Investments (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>75090 - Statement - Consolidated Schedule of Investments (Unfunded Commitments) (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/StatementConsolidatedScheduleOfInvestmentsUnfundedCommitmentsUnaudited</Role>
      <ShortName>Consolidated Schedule of Investments (Unfunded Commitments) (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>75100 - Statement - Consolidated Schedule of Investments (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/StatementConsolidatedScheduleOfInvestmentsParenthetical</Role>
      <ShortName>Consolidated Schedule of Investments (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>75110 - Statement - Consolidated Schedule of Investments (Foreign Currency Forward Contracts) (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/StatementConsolidatedScheduleOfInvestmentsForeignCurrencyForwardContractsUnaudited</Role>
      <ShortName>Consolidated Schedule of Investments (Foreign Currency Forward Contracts) (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>995410 - Disclosure - Pay vs Performance Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/PvpDisclosure</Role>
      <ShortName>Pay vs Performance Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>995445 - Disclosure - Insider Trading Arrangements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements</Role>
      <ShortName>Insider Trading Arrangements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>995455 - Disclosure - Organization</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureOrganization</Role>
      <ShortName>Organization</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>995465 - Disclosure - Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureSignificantAccountingPolicies</Role>
      <ShortName>Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>995475 - Disclosure - Agreements and Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureAgreementsAndRelatedPartyTransactions</Role>
      <ShortName>Agreements and Related Party Transactions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>995485 - Disclosure - Investments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureInvestments</Role>
      <ShortName>Investments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>995495 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFairValueMeasurements1</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>995505 - Disclosure - Derivatives</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureDerivatives</Role>
      <ShortName>Derivatives</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>995515 - Disclosure - Borrowings</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureBorrowings</Role>
      <ShortName>Borrowings</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>995525 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>995535 - Disclosure - Net Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureNetAssets</Role>
      <ShortName>Net Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>995545 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureEarningsPerShare1</Role>
      <ShortName>Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>995555 - Disclosure - Financial Highlights</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFinancialHighlights</Role>
      <ShortName>Financial Highlights</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>995565 - Disclosure - Segment Reporting</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureSegmentReporting</Role>
      <ShortName>Segment Reporting</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>995575 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureSubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>995585 - Disclosure - Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.diametercap.com/20260331/taxonomy/role/DisclosureSignificantAccountingPolicies</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>995595 - Disclosure - Agreements and Related Party Transactions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureAgreementsAndRelatedPartyTransactionsTables</Role>
      <ShortName>Agreements and Related Party Transactions (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.diametercap.com/20260331/taxonomy/role/DisclosureAgreementsAndRelatedPartyTransactions</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>995605 - Disclosure - Investments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureInvestmentsTables</Role>
      <ShortName>Investments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.diametercap.com/20260331/taxonomy/role/DisclosureInvestments</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>995615 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFairValueMeasurements1</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>995625 - Disclosure - Derivatives (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureDerivativesTables</Role>
      <ShortName>Derivatives (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.diametercap.com/20260331/taxonomy/role/DisclosureDerivatives</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>995635 - Disclosure - Borrowings (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureBorrowingsTables</Role>
      <ShortName>Borrowings (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.diametercap.com/20260331/taxonomy/role/DisclosureBorrowings</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>995645 - Disclosure - Net Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureNetAssetsTables</Role>
      <ShortName>Net Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.diametercap.com/20260331/taxonomy/role/DisclosureNetAssets</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>995655 - Disclosure - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureEarningsPerShareTables</Role>
      <ShortName>Earnings Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.diametercap.com/20260331/taxonomy/role/DisclosureEarningsPerShare1</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>995665 - Disclosure - Financial Highlights (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFinancialHighlightsTables</Role>
      <ShortName>Financial Highlights (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFinancialHighlights</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>995675 - Disclosure - Subsequent Events (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureSubsequentEventsTables</Role>
      <ShortName>Subsequent Events (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.diametercap.com/20260331/taxonomy/role/DisclosureSubsequentEvents</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>995685 - Disclosure - Organization - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureOrganizationAdditionalInformationDetails</Role>
      <ShortName>Organization - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>995695 - Disclosure - Significant Accounting Policies - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureSignificantAccountingPoliciesAdditionalInformationDetails</Role>
      <ShortName>Significant Accounting Policies - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>995705 - Disclosure - Agreements and Related Party Transactions - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureAgreementsAndRelatedPartyTransactionsAdditionalInformationDetails</Role>
      <ShortName>Agreements and Related Party Transactions - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>995715 - Disclosure - Agreements and Related Party Transactions - Summary of Expense Payments and Reimbursement Payments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureAgreementsAndRelatedPartyTransactionsSummaryOfExpensePaymentsAndReimbursementPaymentsDetails</Role>
      <ShortName>Agreements and Related Party Transactions - Summary of Expense Payments and Reimbursement Payments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>995725 - Disclosure - Investments - Investment Portfolio at Cost and Fair Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureInvestmentsInvestmentPortfolioAtCostAndFairValueDetails</Role>
      <ShortName>Investments - Investment Portfolio at Cost and Fair Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>995735 - Disclosure - Investments - Industry Composition Of Investments at Fair Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureInvestmentsIndustryCompositionOfInvestmentsAtFairValueDetails</Role>
      <ShortName>Investments - Industry Composition Of Investments at Fair Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>995745 - Disclosure - Investments - Geographic Composition of Investments at Cost and Fair Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureInvestmentsGeographicCompositionOfInvestmentsAtCostAndFairValueDetails</Role>
      <ShortName>Investments - Geographic Composition of Investments at Cost and Fair Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>995755 - Disclosure - Investments - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureInvestmentsAdditionalInformationDetails</Role>
      <ShortName>Investments - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>995765 - Disclosure - Fair Value Measurements - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFairValueMeasurementsAdditionalInformationDetails</Role>
      <ShortName>Fair Value Measurements - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>995775 - Disclosure - Fair Value Measurements - Summary of Fair Value Hierarchy of Financial Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFairValueMeasurementsSummaryOfFairValueHierarchyOfFinancialInstrumentsDetails</Role>
      <ShortName>Fair Value Measurements - Summary of Fair Value Hierarchy of Financial Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>995785 - Disclosure - Fair Value Measurements - Summary of Fair Value Hierarchy of Financial Instruments (Parenthetical) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFairValueMeasurementsSummaryOfFairValueHierarchyOfFinancialInstrumentsParentheticalDetails</Role>
      <ShortName>Fair Value Measurements - Summary of Fair Value Hierarchy of Financial Instruments (Parenthetical) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>995795 - Disclosure - Fair Value Measurements - Summary of Changes in Fair Value of Financial Instruments Level 3 Inputs (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFairValueMeasurementsSummaryOfChangesInFairValueOfFinancialInstrumentsLevel3InputsDetails</Role>
      <ShortName>Fair Value Measurements - Summary of Changes in Fair Value of Financial Instruments Level 3 Inputs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>995805 - Disclosure - Fair Value Measurements - Summary of Quantitative Information about the Significant Unobservable Inputs of the Company's Level 3 Financial Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFairValueMeasurementsSummaryOfQuantitativeInformationAboutTheSignificantUnobservableInputsOfTheCompanysLevel3FinancialInstruments</Role>
      <ShortName>Fair Value Measurements - Summary of Quantitative Information about the Significant Unobservable Inputs of the Company's Level 3 Financial Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>995815 - Disclosure - Derivatives - Schedule of Aggregate Notional Amount and Fair Value Hierarchy of Derivative Financial Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureDerivativesScheduleOfAggregateNotionalAmountAndFairValueHierarchyOfDerivativeFinancialInstrumentsDetails</Role>
      <ShortName>Derivatives - Schedule of Aggregate Notional Amount and Fair Value Hierarchy of Derivative Financial Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>995835 - Disclosure - Derivatives - Schedule of Impact to Consolidated Statements of Operations from Derivative Instruments Not Designated in Qualifying Hedge Accounting Relationship (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureDerivativesScheduleOfImpactToConsolidatedStatementsOfOperationsFromDerivativeInstrumentsNotDesignatedInQualifyingHedgeAccountingR</Role>
      <ShortName>Derivatives - Schedule of Impact to Consolidated Statements of Operations from Derivative Instruments Not Designated in Qualifying Hedge Accounting Relationship (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>995855 - Disclosure - Derivatives - Schedule of Offsetting of Derivative Instruments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureDerivativesScheduleOfOffsettingOfDerivativeInstrumentsDetails</Role>
      <ShortName>Derivatives - Schedule of Offsetting of Derivative Instruments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>995875 - Disclosure - Borrowings - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureBorrowingsAdditionalInformationDetails</Role>
      <ShortName>Borrowings - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>995885 - Disclosure - Borrowings - Schedule of Secured Notes and Subordinated Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureBorrowingsScheduleOfSecuredNotesAndSubordinatedNotesDetails</Role>
      <ShortName>Borrowings - Schedule of Secured Notes and Subordinated Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>995895 - Disclosure - Borrowings - Schedule of Secured Notes and Subordinated Notes (Parenthetical) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureBorrowingsScheduleOfSecuredNotesAndSubordinatedNotesParentheticalDetails</Role>
      <ShortName>Borrowings - Schedule of Secured Notes and Subordinated Notes (Parenthetical) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>995905 - Disclosure - Borrowings - Schedule of Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureBorrowingsScheduleOfAssetsAndLiabilitiesDetails</Role>
      <ShortName>Borrowings - Schedule of Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>995915 - Disclosure - Borrowings - Schedule of Assets and Liabilities (Parenthetical) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureBorrowingsScheduleOfAssetsAndLiabilitiesParentheticalDetails</Role>
      <ShortName>Borrowings - Schedule of Assets and Liabilities (Parenthetical) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>995925 - Disclosure - Borrowings - Schedule of Repurchase Agreements (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureBorrowingsScheduleOfRepurchaseAgreementsDetails</Role>
      <ShortName>Borrowings - Schedule of Repurchase Agreements (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>995935 - Disclosure - Borrowings - Schedule of Outstanding Debt Obligations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureBorrowingsScheduleOfOutstandingDebtObligationsDetails</Role>
      <ShortName>Borrowings - Schedule of Outstanding Debt Obligations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>995945 - Disclosure - Borrowings - Components of Interest Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureBorrowingsComponentsOfInterestExpenseDetails</Role>
      <ShortName>Borrowings - Components of Interest Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>995955 - Disclosure - Commitments and Contingencies - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureCommitmentsAndContingenciesAdditionalInformationDetails</Role>
      <ShortName>Commitments and Contingencies - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>995965 - Disclosure - Net Assets - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureNetAssetsAdditionalInformationDetails</Role>
      <ShortName>Net Assets - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>995975 - Disclosure - Net Assets - Summary of Shares Issued and Proceeds Received (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureNetAssetsSummaryOfSharesIssuedAndProceedsReceivedDetails</Role>
      <ShortName>Net Assets - Summary of Shares Issued and Proceeds Received (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>995985 - Disclosure - Net Assets - Summary of Distributions Declared (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureNetAssetsSummaryOfDistributionsDeclaredDetails</Role>
      <ShortName>Net Assets - Summary of Distributions Declared (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>995995 - Disclosure - Net Assets - Summary of Shares Issued and Value under Distribution Reinvestment Plan (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureNetAssetsSummaryOfSharesIssuedAndValueUnderDistributionReinvestmentPlanDetails</Role>
      <ShortName>Net Assets - Summary of Shares Issued and Value under Distribution Reinvestment Plan (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>996005 - Disclosure - Earnings Per Share - Schedule of computation of Net Increase (Decrease) in Net Assets per Common Share Resulting from Operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureEarningsPerShareScheduleOfComputationOfNetIncreaseDecreaseInNetAssetsPerCommonShareResultingFromOperationsDetails</Role>
      <ShortName>Earnings Per Share - Schedule of computation of Net Increase (Decrease) in Net Assets per Common Share Resulting from Operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>996015 - Disclosure - Financial Highlights - Schedule of Financial Highlights (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFinancialHighlightsScheduleOfFinancialHighlightsDetails</Role>
      <ShortName>Financial Highlights - Schedule of Financial Highlights (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>996025 - Disclosure - Financial Highlights and Senior Securities - information about senior securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFinancialHighlightsAndSeniorSecuritiesInformationAboutSeniorSecuritiesDetails</Role>
      <ShortName>Financial Highlights and Senior Securities - information about senior securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>996035 - Disclosure - Financial Highlights - Schedule of Financial Highlights (Parenthetical) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureFinancialHighlightsScheduleOfFinancialHighlightsParentheticalDetails</Role>
      <ShortName>Financial Highlights - Schedule of Financial Highlights (Parenthetical) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>996045 - Disclosure - Segment Reporting - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureSegmentReportingAdditionalInformationDetails</Role>
      <ShortName>Segment Reporting - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>996055 - Disclosure - Subsequent Events - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureSubsequentEventsAdditionalInformationDetails</Role>
      <ShortName>Subsequent Events - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>996065 - Disclosure - Subsequent Events - Schedule of CLO 2 Notes (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureSubsequentEventsScheduleOfClo2NotesDetails</Role>
      <ShortName>Subsequent Events - Schedule of CLO 2 Notes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="ck0001916099-20260331.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>996075 - Disclosure - Subsequent Events - Schedule of CLO 2 Notes (Parenthetical) (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.diametercap.com/20260331/taxonomy/role/DisclosureSubsequentEventsScheduleOfClo2NotesParentheticalDetails</Role>
      <ShortName>Subsequent Events - Schedule of CLO 2 Notes (Parenthetical) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>74</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" isDefinitelyFs="true" isUsgaap="true" original="ck0001916099-20260331.htm">ck0001916099-20260331.htm</File>
    <File>ck0001916099-20260331.xsd</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="4087">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="28">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="4">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>false</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
