<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:cef="http://xbrl.sec.gov/cef/2026"
  xmlns:dei="http://xbrl.sec.gov/dei/2026"
  xmlns:evtmdeif="http://www.eatonvance.com/20260623"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:us-gaap="http://fasb.org/us-gaap/2026"
  xmlns:xbrldi="http://xbrl.org/2006/xbrldi"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef xlink:href="evtmdeif-20260623.xsd" xlink:type="simple"/>
    <context id="c0">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001340736</identifier>
        </entity>
        <period>
            <startDate>2026-06-23</startDate>
            <endDate>2026-06-23</endDate>
        </period>
    </context>
    <context id="c1">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001340736</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">evtmdeif:CommonSharesTaxManagedDiversifiedEquityIncomeFundMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-06-23</startDate>
            <endDate>2026-06-23</endDate>
        </period>
    </context>
    <unit id="shares">
        <measure>shares</measure>
    </unit>
    <dei:EntityRegistrantName contextRef="c0" id="ixv-2905">Eaton Vance Tax-Managed Diversified Equity Income Fund</dei:EntityRegistrantName>
    <cef:OutstandingSecuritiesTableTextBlock contextRef="c0" id="ixv-358">

&lt;table cellpadding="0" style="width:90%;cellspacing:0;padding-bottom:2pt;padding-top:0pt;margin-left:30.5pt; border-spacing: 0px;" width="90%"&gt;
  &lt;tr style="height:1px;"&gt;
    &lt;td style="height:1px; width: 46%;"&gt;&lt;/td&gt;
    &lt;td style="height:1px; width: 27%;"&gt;&lt;/td&gt;
    &lt;td style="height:1px; width: 27%;"&gt;&lt;/td&gt;&lt;/tr&gt;
  &lt;tr&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: left;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: left;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt;text-decoration: underline;text-underline-offset: 2pt; font-family: Arial, Helvetica, sans-serif;"&gt;Fund&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: center;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:center;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: center;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;No.
        of Common Shares&lt;/span&gt;&lt;br/&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt;margin-left:NaNpt;text-decoration: underline;text-underline-offset: 2pt; font-family: Arial, Helvetica, sans-serif;"&gt;Outstanding
        on June 2, 2026&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: center;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:center;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: center;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;No.
        of APS&lt;/span&gt;&lt;br/&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt;margin-left:NaNpt;text-decoration: underline;text-underline-offset: 2pt; font-family: Arial, Helvetica, sans-serif;"&gt;Outstanding
        on June 2, 2026&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
  &lt;tr&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: left;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: left;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;Senior
        Floating-Rate Trust&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: center; white-space: nowrap;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:center;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: center;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;29,523,618&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: center; white-space: nowrap;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:center;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: center;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;20&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
  &lt;tr&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: left;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: left;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;Tax-Advantaged
        Dividend Income Fund&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: center; white-space: nowrap;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:center;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: center;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;74,542,782&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: center; white-space: nowrap;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:center;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: center;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;&#x2013;&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
  &lt;tr&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: left;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: left;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;Tax-Advantaged
        Global Dividend Income Fund&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: center; white-space: nowrap;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:center;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: center;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;76,321,908&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: center; white-space: nowrap;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:center;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: center;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;&#x2013;&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
  &lt;tr&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: left;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: left;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;Tax-Managed
        Diversified Equity Income Fund&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: center; white-space: nowrap;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:center;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: center;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;159,280,608&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: center; white-space: nowrap;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:center;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: center;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;&#x2013;&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
  &lt;tr&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: left;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: left;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;Tax-Managed
        Global Diversified Equity Income Fund&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: center; white-space: nowrap;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:center;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: center;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;305,936,026&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td colspan="1" style="padding-bottom:2pt;padding-top:3pt;vertical-align:bottom; text-align: center; white-space: nowrap;" valign="bottom"&gt;
        &lt;p style="font-family:Arial, Helvetica, sans-serif;font-size:10pt;background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:center;padding-right:2pt;margin-top:4pt;margin-bottom:0; text-align: center;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;&#x2013;&lt;/span&gt;&lt;/p&gt;&lt;/td&gt;&lt;/tr&gt;
  &lt;/table&gt;</cef:OutstandingSecuritiesTableTextBlock>
    <cef:OutstandingSecurityTitleTextBlock contextRef="c1" id="ixv-411">&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:8.02pt; font-family: Arial, Helvetica, sans-serif;"&gt;Tax-Managed
        Diversified Equity Income Fund&lt;/span&gt;</cef:OutstandingSecurityTitleTextBlock>
    <cef:OutstandingSecurityAuthorizedShares contextRef="c1" decimals="0" id="ixv-2906" unitRef="shares">159280608</cef:OutstandingSecurityAuthorizedShares>
    <dei:DocumentType contextRef="c0" id="hidden-fact-0">DEF 14A</dei:DocumentType>
    <dei:EntityCentralIndexKey contextRef="c0" id="ixv-2910">0001340736</dei:EntityCentralIndexKey>
    <dei:AmendmentFlag contextRef="c0" id="ixv-2911">false</dei:AmendmentFlag>
</xbrl>
