<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xml:lang="en-US"
  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"
  xmlns:xbrldi="http://xbrl.org/2006/xbrldi"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef
      xlink:href="https://xbrl.sec.gov/ffd/2026/ffd-2026.xsd"
      xlink:type="simple"/>
    <context id="c-1">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000947484</identifier>
        </entity>
        <period>
            <startDate>2026-06-04</startDate>
            <endDate>2026-06-04</endDate>
        </period>
    </context>
    <context id="c-2">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000947484</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>1</dei:lineNo>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-06-04</startDate>
            <endDate>2026-06-04</endDate>
        </period>
    </context>
    <context id="c-3">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000947484</identifier>
            <segment>
                <xbrldi:typedMember dimension="ffd:OfferingAxis">
                    <dei:lineNo>2</dei:lineNo>
                </xbrldi:typedMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-06-04</startDate>
            <endDate>2026-06-04</endDate>
        </period>
    </context>
    <unit id="usd">
        <measure>iso4217:USD</measure>
    </unit>
    <unit id="number">
        <measure>pure</measure>
    </unit>
    <ffd:FormTp contextRef="c-1" id="f-27">S-3</ffd:FormTp>
    <ffd:SubmissnTp contextRef="c-1" id="f-28">424B2</ffd:SubmissnTp>
    <ffd:FeeExhibitTp contextRef="c-1" id="f-29">EX-FILING FEES</ffd:FeeExhibitTp>
    <dei:EntityCentralIndexKey contextRef="c-1" id="f-30">0000947484</dei:EntityCentralIndexKey>
    <ffd:RegnFileNb contextRef="c-1" id="f-31">333-275570</ffd:RegnFileNb>
    <ffd:OffsetTableNa contextRef="c-1" id="f-32">N/A</ffd:OffsetTableNa>
    <ffd:CombinedProspectusTableNa contextRef="c-1" id="f-33">N/A</ffd:CombinedProspectusTableNa>
    <dei:EntityRegistrantName contextRef="c-1" id="f-1">Arch Capital Group Ltd.</dei:EntityRegistrantName>
    <ffd:PrevslyPdFlg contextRef="c-2" id="f-2">false</ffd:PrevslyPdFlg>
    <ffd:OfferingSctyTp contextRef="c-2" id="f-3">Debt</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="c-2" id="f-4">5.250% Notes due 2036</ffd:OfferingSctyTitl>
    <ffd:Rule457rFlg contextRef="c-2" id="f-5">true</ffd:Rule457rFlg>
    <ffd:AmtSctiesRegd contextRef="c-2" decimals="0" id="f-6" unitRef="usd">600000000</ffd:AmtSctiesRegd>
    <ffd:MaxOfferingPricPerScty contextRef="c-2" decimals="5" id="f-7" unitRef="number">0.99576</ffd:MaxOfferingPricPerScty>
    <ffd:MaxAggtOfferingPric contextRef="c-2" decimals="2" id="f-8" unitRef="usd">597456000</ffd:MaxAggtOfferingPric>
    <ffd:FeeRate contextRef="c-2" decimals="7" id="f-9" unitRef="number">0.0001381</ffd:FeeRate>
    <ffd:FeeAmt contextRef="c-2" decimals="2" id="f-10" unitRef="usd">82508.67</ffd:FeeAmt>
    <ffd:PrevslyPdFlg contextRef="c-3" id="f-11">false</ffd:PrevslyPdFlg>
    <ffd:OfferingSctyTp contextRef="c-3" id="f-12">Debt</ffd:OfferingSctyTp>
    <ffd:OfferingSctyTitl contextRef="c-3" id="f-13">5.950% Notes due 2056</ffd:OfferingSctyTitl>
    <ffd:Rule457rFlg contextRef="c-3" id="f-14">true</ffd:Rule457rFlg>
    <ffd:AmtSctiesRegd contextRef="c-3" decimals="0" id="f-15" unitRef="usd">1400000000</ffd:AmtSctiesRegd>
    <ffd:MaxOfferingPricPerScty contextRef="c-3" decimals="5" id="f-16" unitRef="number">0.99693</ffd:MaxOfferingPricPerScty>
    <ffd:MaxAggtOfferingPric contextRef="c-3" decimals="2" id="f-17" unitRef="usd">1395702000</ffd:MaxAggtOfferingPric>
    <ffd:FeeRate contextRef="c-3" decimals="7" id="f-18" unitRef="number">0.0001381</ffd:FeeRate>
    <ffd:FeeAmt contextRef="c-3" decimals="2" id="f-19" unitRef="usd">192746.45</ffd:FeeAmt>
    <ffd:TtlOfferingAmt contextRef="c-1" decimals="2" id="f-20" unitRef="usd">1993158000</ffd:TtlOfferingAmt>
    <ffd:TtlFeeAmt contextRef="c-1" decimals="2" id="f-21" unitRef="usd">275255.12</ffd:TtlFeeAmt>
    <ffd:TtlPrevslyPdAmt contextRef="c-1" decimals="0" id="f-22" unitRef="usd">0</ffd:TtlPrevslyPdAmt>
    <ffd:TtlOffsetAmt contextRef="c-1" decimals="0" id="f-23" unitRef="usd">0</ffd:TtlOffsetAmt>
    <ffd:NetFeeAmt contextRef="c-1" decimals="2" id="f-24" unitRef="usd">275255.12</ffd:NetFeeAmt>
    <ffd:OfferingNote contextRef="c-3" id="f-26">&lt;span style="color:#000000;font-family:'Times New Roman',serif;font-size:8pt;font-weight:400;line-height:112%"&gt;1  Calculated in accordance with Rule 457(r) under the Securities Act of 1933, as amended.&lt;/span&gt;</ffd:OfferingNote>
    <ffd:OfferingNote contextRef="c-2" id="f-25">&lt;span style="color:#000000;font-family:'Times New Roman',serif;font-size:8pt;font-weight:400;line-height:112%"&gt;1  Calculated in accordance with Rule 457(r) under the Securities Act of 1933, as amended.&lt;/span&gt;</ffd:OfferingNote>
</xbrl>
