<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2026"
  xmlns:ecd="http://xbrl.sec.gov/ecd/2026"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xbrldi="http://xbrl.org/2006/xbrldi"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef xlink:href="ctor-20250930.xsd" xlink:type="simple"/>
    <context id="cref_620239763">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001851484</identifier>
        </entity>
        <period>
            <startDate>2024-10-01</startDate>
            <endDate>2025-09-30</endDate>
        </period>
    </context>
    <context id="cref_223983604">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001851484</identifier>
            <segment>
                <xbrldi:typedMember dimension="ecd:RestatementDateAxis">
                    <ecd:RestatementDateAxis.domain>2025-09-30</ecd:RestatementDateAxis.domain>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2024-10-01</startDate>
            <endDate>2025-09-30</endDate>
        </period>
    </context>
    <dei:EntityCentralIndexKey contextRef="cref_620239763" id="ixv-4658">0001851484</dei:EntityCentralIndexKey>
    <dei:AmendmentFlag contextRef="cref_620239763" id="ixv-4659">false</dei:AmendmentFlag>
    <dei:DocumentType contextRef="cref_620239763" id="fc_1180645600">DEF 14A</dei:DocumentType>
    <dei:EntityRegistrantName contextRef="cref_620239763" id="ixv-4679">Citius Oncology, Inc.</dei:EntityRegistrantName>
    <ecd:InsiderTrdPoliciesProcAdoptedFlag contextRef="cref_620239763" id="ixv-4680">true</ecd:InsiderTrdPoliciesProcAdoptedFlag>
    <ecd:RestatementDoesNotRequireRecoveryTextBlock contextRef="cref_223983604" id="ixv-1753">&lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in;"&gt;&lt;span style="font-family: Times New Roman, Times, Serif;"&gt;We have adopted a clawback policy to provide for the recovery of erroneously-awarded incentive compensation, as required by the Dodd-Frank Act, final SEC rules and applicable listing standards.&lt;/span&gt;&lt;/p&gt;</ecd:RestatementDoesNotRequireRecoveryTextBlock>
    <ecd:AwardTmgMnpiDiscTextBlock contextRef="cref_620239763" id="ixv-2226">&lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0;"&gt;&lt;span style="font-family: Times New Roman, Times, Serif;"&gt;&lt;span style="font-weight: bold;"&gt;Policies and Practices Related to the Grant of Certain Equity Awards Close in Time to the Release of Material Nonpublic Information&lt;/span&gt;&lt;/span&gt;&lt;/p&gt; &lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0;"&gt;&lt;span style="font-family: Times New Roman, Times, Serif;"&gt;&#160;&lt;/span&gt;&lt;/p&gt; &lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in;"&gt; &lt;span style="font-family: Times New Roman, Times, Serif;"&gt;While&#160;we do not have a formal written policy in place with regard to the timing of awards of options or similar awards in relation to the disclosure of material nonpublic information, our equity awards are generally granted on fixed dates&#160;determined in advance. On limited occasions, our Compensation Committee or Board of Directors may grant equity awards outside of our annual grant cycle for new hires, promotions, recognition, retention or other purposes.&lt;/span&gt; &lt;/p&gt; &lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0;"&gt;&lt;span style="font-family: Times New Roman, Times, Serif;"&gt;&#160;&lt;/span&gt;&lt;/p&gt; &lt;p style="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in;"&gt; &lt;span style="font-family: Times New Roman, Times, Serif;"&gt;&lt;/span&gt;&lt;span style="font-family: Times New Roman, Times, Serif;"&gt;The Compensation Committee approves all equity award grants on or before the grant date and does not grant equity awards in anticipation of the release of material nonpublic information. Similarly, the Compensation Committee does&#160;not time the release of material nonpublic information&#160;based on equity award grant dates.&lt;/span&gt;&lt;span style="font-family: Times New Roman, Times, Serif;"&gt; Going forward, the Compensation Committee will not grant awards to executive officers on the same day as directors.&lt;/span&gt; &lt;/p&gt;</ecd:AwardTmgMnpiDiscTextBlock>
    <ecd:AwardTmgMethodTextBlock contextRef="cref_620239763" id="ixv-4681">While&#160;we do not have a formal written policy in place with regard to the timing of awards of options or similar awards in relation to the disclosure of material nonpublic information, our equity awards are generally granted on fixed dates&#160;determined in advance. On limited occasions, our Compensation Committee or Board of Directors may grant equity awards outside of our annual grant cycle for new hires, promotions, recognition, retention or other purposes.</ecd:AwardTmgMethodTextBlock>
    <ecd:MnpiDiscTimedForCompValFlag contextRef="cref_620239763" id="ixv-4682">false</ecd:MnpiDiscTimedForCompValFlag>
    <ecd:AwardTmgPredtrmndFlag contextRef="cref_620239763" id="ixv-4683">true</ecd:AwardTmgPredtrmndFlag>
    <ecd:AwardTmgHowMnpiCnsdrdTextBlock contextRef="cref_620239763" id="ixv-2238">&lt;span style="font-family: Times New Roman, Times, Serif;"&gt;The Compensation Committee approves all equity award grants on or before the grant date and does not grant equity awards in anticipation of the release of material nonpublic information. Similarly, the Compensation Committee does&#160;not time the release of material nonpublic information&#160;based on equity award grant dates.&lt;/span&gt;&lt;span style="font-family: Times New Roman, Times, Serif;"&gt; Going forward, the Compensation Committee will not grant awards to executive officers on the same day as directors.&lt;/span&gt;</ecd:AwardTmgHowMnpiCnsdrdTextBlock>
    <ecd:AwardTmgMnpiCnsdrdFlag contextRef="cref_620239763" id="ixv-4684">false</ecd:AwardTmgMnpiCnsdrdFlag>
</xbrl>
