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  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2026"
  xmlns:ffd="http://xbrl.sec.gov/ffd/2026"
  xmlns:iso4217="http://www.xbrl.org/2003/iso4217"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
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  xmlns:xlink="http://www.w3.org/1999/xlink"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <link:schemaRef
      xlink:href="https://xbrl.sec.gov/ffd/2026/ffd-2026.xsd"
      xlink:type="simple"/>
    <context id="rc">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000091576</identifier>
        </entity>
        <period>
            <startDate>2026-06-04</startDate>
            <endDate>2026-06-04</endDate>
        </period>
    </context>
    <context id="offrl_1">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000091576</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>1</dei:lineNo>
                </xbrldi:typedMember>
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        </entity>
        <period>
            <startDate>2026-06-04</startDate>
            <endDate>2026-06-04</endDate>
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    </context>
    <unit id="USD">
        <measure>iso4217:USD</measure>
    </unit>
    <unit id="Shares">
        <measure>shares</measure>
    </unit>
    <ffd:FormTp contextRef="rc" id="ixv-330">S-3</ffd:FormTp>
    <ffd:SubmissnTp contextRef="rc" id="ixv-331">S-3</ffd:SubmissnTp>
    <ffd:FeeExhibitTp contextRef="rc" id="ixv-332">EX-FILING FEES</ffd:FeeExhibitTp>
    <dei:EntityCentralIndexKey contextRef="rc" id="ixv-333">0000091576</dei:EntityCentralIndexKey>
    <dei:EntityRegistrantName contextRef="rc" id="ixv-334">KEYCORP /NEW/</dei:EntityRegistrantName>
    <ffd:OfferingTableNa contextRef="rc" id="hiddenrcOfferingTableNa" xsi:nil="true"/>
    <ffd:OffsetTableNa contextRef="rc" id="hiddenrcOffsetTableNa">N/A</ffd:OffsetTableNa>
    <ffd:CombinedProspectusTableNa contextRef="rc" id="hiddenrcCombinedProspectusTableNa">N/A</ffd:CombinedProspectusTableNa>
    <ffd:FormTp contextRef="rc" id="ixv-362">S-3</ffd:FormTp>
    <dei:EntityRegistrantName contextRef="rc" id="ixv-363">KEYCORP /NEW/</dei:EntityRegistrantName>
    <ffd:OfferingSctyTp contextRef="offrl_1" id="ixv-364">Equity</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="offrl_1" id="ixv-365">Common Shares, par value $1.00</ffd:OfferingSctyTitl>
    <ffd:Rule415a6Flg contextRef="offrl_1" id="ixv-366">true</ffd:Rule415a6Flg>
    <ffd:AmtSctiesRegd
      contextRef="offrl_1"
      decimals="0"
      id="ixv-367"
      unitRef="Shares">158723874</ffd:AmtSctiesRegd>
    <ffd:MaxAggtOfferingPric
      contextRef="offrl_1"
      decimals="2"
      id="ixv-368"
      unitRef="USD">3295107624.24</ffd:MaxAggtOfferingPric>
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    <ffd:CfwdPrrFileNb contextRef="offrl_1" id="ixv-370">333-272573</ffd:CfwdPrrFileNb>
    <ffd:CfwdPrrFctvDt contextRef="offrl_1" id="ixv-371">2023-06-09</ffd:CfwdPrrFctvDt>
    <ffd:CfwdPrevslyPdFee
      contextRef="offrl_1"
      decimals="2"
      id="ixv-372"
      unitRef="USD">455054.36</ffd:CfwdPrevslyPdFee>
    <ffd:TtlOfferingAmt contextRef="rc" decimals="2" id="ixv-373" unitRef="USD">3295107624.24</ffd:TtlOfferingAmt>
    <ffd:TtlFeeAmt contextRef="rc" decimals="2" id="ixv-374" unitRef="USD">0.00</ffd:TtlFeeAmt>
    <ffd:TtlPrevslyPdAmt contextRef="rc" decimals="2" id="ixv-375" unitRef="USD">0.00</ffd:TtlPrevslyPdAmt>
    <ffd:TtlOffsetAmt contextRef="rc" decimals="2" id="ixv-376" unitRef="USD">0.00</ffd:TtlOffsetAmt>
    <ffd:NetFeeAmt contextRef="rc" decimals="2" id="ixv-377" unitRef="USD">0.00</ffd:NetFeeAmt>
    <ffd:OfferingNote contextRef="offrl_1" id="ixv-378">(1) This Registration Statement on Form S-3 (this "Registration Statement") of KeyCorp (the "Registrant") shall also cover such an indeterminate number of additional common shares, as may hereafter be offered or issued as a result of any stock splits, stock dividends, recapitalizations or similar transactions. (2) Pursuant to Rule 415(a)(6) under the Securities Act, the securities registered pursuant to this Registration Statement consist of 158,723,874 common shares (the "Unsold Securities") that may be sold by the selling shareholder. The Unsold Securities were previously registered for sale pursuant to the Registration Statement on Form S-3ASR (File No. 333-272573), originally filed with the Securities and Exchange Commission (the "SEC") on June 9, 2023 (the "Prior Registration Statement"), as supplemented by the prospectus supplement filed pursuant to Rule 424(b)(7) on December 23, 2025 (the "Prior Prospectus Supplement"). The Registrant previously paid filing fees for the Unsold Securities in an aggregate amount of $455,054.36. Pursuant to Rule 415(a)(6) under the Securities Act, the Unsold Securities are being carried forward and the filing fee previously paid in connection with the Unsold Securities will continue to be applied to the Unsold Securities registered hereunder. Pursuant to Rule 415(a)(6), the offering of securities under the Prior Prospectus Supplement will be deemed terminated as of the date of effectiveness of this Registration Statement.</ffd:OfferingNote>
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