<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2026"
  xmlns:fnd="http://xbrl.sec.gov/fnd/2026"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef xlink:href="ft13088-20260720.xsd" xlink:type="simple"/>
    <context id="AsOf2026-07-20">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0002132613</identifier>
        </entity>
        <period>
            <startDate>2026-07-20</startDate>
            <endDate>2026-07-20</endDate>
        </period>
    </context>
    <dei:AmendmentFlag contextRef="AsOf2026-07-20" id="Fact000003">false</dei:AmendmentFlag>
    <dei:EntityCentralIndexKey contextRef="AsOf2026-07-20" id="Fact000004">0002132613</dei:EntityCentralIndexKey>
    <dei:DocumentType contextRef="AsOf2026-07-20" id="Fact000010">S-6</dei:DocumentType>
    <dei:EntityRegistrantName contextRef="AsOf2026-07-20" id="Fact000011">FT 13088</dei:EntityRegistrantName>
    <dei:DocumentPeriodEndDate contextRef="AsOf2026-07-20" id="Fact000012">2026-07-20</dei:DocumentPeriodEndDate>
    <fnd:NmRule35d1TermDfnTextBlock contextRef="AsOf2026-07-20" id="Fact000013">

&lt;p style="font: bold 11pt/12pt Times New Roman, Times, Serif; margin: 4pt 0 1pt"&gt;Objective.&lt;/p&gt;

&lt;p style="font: 10pt/11pt Times New Roman, Times, Serif; margin: 0 0 2pt; text-indent: 0.25in"&gt;The Trust seeks above-average capital
appreciation by investing in a diversified portfolio of common stocks issued by water utility and infrastructure companies. &lt;span style="letter-spacing: -0.05pt"&gt;Under
normal circumstances, the Trust invests at least 80% of its assets in Water Utility Companies (as defined below) and/or
Infrastructure Companies (as defined below). Water Utility Companies are companies that operate water utility facilities or provide
products, software, or services used in the development or operation of water utility facilities, and may include companies
classified under the water utility and multi-utility sub-industries of the Global Industry Classification Standard
(GICS&lt;sup&gt;&#xae;&lt;/sup&gt;). Infrastructure Companies are companies the Sponsor believes will benefit from the investment in water
related infrastructure which are companies involved in the development or manufacturing of water treatment chemicals, water pipes
and valves, construction and engineering of water infrastructure, electronic equipment and software for monitoring and analyzing
water infrastructure, and building products relating to water transportation. &lt;/span&gt;The Trust is concentrated &lt;span style="letter-spacing: -0.05pt"&gt;(i.e.,
invests 25% or more of Trust assets) &lt;/span&gt;in common stocks of companies within the industrials sector.&lt;/p&gt;

</fnd:NmRule35d1TermDfnTextBlock>
    <fnd:NmRule35d1TermSlctnCritTextBlock contextRef="AsOf2026-07-20" id="Fact000014">

&lt;p style="font: bold 11pt/12pt Times New Roman, Times, Serif; margin: 4pt 0 1pt"&gt;Portfolio Selection Process.&lt;/p&gt;

&lt;p style="font: 10pt/11pt Times New Roman, Times, Serif; margin: 0 0 2pt; text-indent: 0.25in"&gt;&lt;span style="letter-spacing: -0.05pt"&gt;Our
selection process attempts to find the common stocks with the best prospects for above-average capital appreciation by identifying those
that meet our investment objective, trade at attractive valuations, and, in our opinion, are likely to exceed market expectations of future
cash flows.&lt;/span&gt;&lt;/p&gt;

&lt;p style="font: 10pt/11pt Times New Roman, Times, Serif; margin: 0 0 2pt; text-indent: 0.25in"&gt;While not a part of the Trust&#x2019;s portfolio
selection process, the Trust also invests in dividend-paying securities, foreign securities, depositary receipts and companies with various
market capitalizations.&lt;/p&gt;

&lt;p style="font: 10pt/11pt Times New Roman, Times, Serif; margin: 0 0 2pt; text-indent: 0.25in"&gt;&lt;span style="letter-spacing: -0.05pt"&gt;As
with any similar investments, there can be no assurance that the objective of the Trust will be achieved. See &#x201c;Risk Factors&#x201d;
for a discussion of the risks of investing in the Trust.&lt;/span&gt;&lt;/p&gt;

</fnd:NmRule35d1TermSlctnCritTextBlock>
</xbrl>
