<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:aon="http://www.aon.com/20260830"
  xmlns:dei="http://xbrl.sec.gov/dei/2025"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:us-gaap="http://fasb.org/us-gaap/2025"
  xmlns:xbrldi="http://xbrl.org/2006/xbrldi"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef xlink:href="aon-20260830.xsd" xlink:type="simple"/>
    <context id="duration_2026-08-30_to_2026-08-30">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_us-gaap-CapitalUnitClassAMember">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">us-gaap:CapitalUnitClassAMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs285SeniorNotesDue2027Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs285SeniorNotesDue2027Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.050SeniorNotesDue20315Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.050SeniorNotesDue20315Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.600SeniorNotesDue20311Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.600SeniorNotesDue20311Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs5.000SeniorNotesDue20322Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs5.000SeniorNotesDue20322Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs5.350SeniorNotesDue20333Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs5.350SeniorNotesDue20333Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.250SeniorNotesDue20429Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonPlcs4.250SeniorNotesDue20429Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.450SeniorNotesDue20436Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonPlcs4.450SeniorNotesDue20436Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.600SeniorNotesDue20447Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonPlcs4.600SeniorNotesDue20447Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.750SeniorNotesDue20458Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonPlcs4.750SeniorNotesDue20458Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.900SeniorNotesDue20514Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.900SeniorNotesDue20514Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs390SeniorNotesDue2052Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs390SeniorNotesDue2052Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.125SeniorNotesDue2027Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonNorthAmericaInc.s5.125SeniorNotesDue2027Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.150SeniorNotesDue2029Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonNorthAmericaInc.s5.150SeniorNotesDue2029Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.300SeniorNotesDue2031Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonNorthAmericaInc.s5.300SeniorNotesDue2031Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.450SeniorNotesDue2034Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonNorthAmericaInc.s5.450SeniorNotesDue2034Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <context id="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.750SeniorNotesDue2054Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000315293</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:StatementClassOfStockAxis">aon:GuaranteesOfAonNorthAmericaInc.s5.750SeniorNotesDue2054Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2026-08-30</startDate>
            <endDate>2026-08-30</endDate>
        </period>
    </context>
    <dei:AmendmentFlag contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-399">false</dei:AmendmentFlag>
    <dei:EntityCentralIndexKey
      contextRef="duration_2026-08-30_to_2026-08-30"
      id="Hidden_dei_EntityCentralIndexKey">0000315293</dei:EntityCentralIndexKey>
    <dei:DocumentType contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-546">8-K</dei:DocumentType>
    <dei:DocumentPeriodEndDate contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-547">2026-08-30</dei:DocumentPeriodEndDate>
    <dei:EntityRegistrantName contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-548">Aon plc</dei:EntityRegistrantName>
    <dei:EntityIncorporationStateCountryCode contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-549">L2</dei:EntityIncorporationStateCountryCode>
    <dei:EntityFileNumber contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-550">1-7933</dei:EntityFileNumber>
    <dei:EntityTaxIdentificationNumber contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-551">98-1539969</dei:EntityTaxIdentificationNumber>
    <dei:EntityAddressAddressLine1 contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-552">15 George&#x2019;s Quay</dei:EntityAddressAddressLine1>
    <dei:EntityAddressCityOrTown contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-553">Dublin 2</dei:EntityAddressCityOrTown>
    <dei:EntityAddressCountry contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-554">IE</dei:EntityAddressCountry>
    <dei:EntityAddressPostalZipCode contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-555">D02 VR98</dei:EntityAddressPostalZipCode>
    <dei:CityAreaCode contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-556">353 1</dei:CityAreaCode>
    <dei:LocalPhoneNumber contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-557">266 6000</dei:LocalPhoneNumber>
    <dei:WrittenCommunications contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-558">false</dei:WrittenCommunications>
    <dei:SolicitingMaterial contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-559">false</dei:SolicitingMaterial>
    <dei:PreCommencementTenderOffer contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-560">false</dei:PreCommencementTenderOffer>
    <dei:PreCommencementIssuerTenderOffer contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-561">false</dei:PreCommencementIssuerTenderOffer>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_us-gaap-CapitalUnitClassAMember"
      id="ixv-562">Class&#160;A Ordinary Shares $0.01 nominal value</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_us-gaap-CapitalUnitClassAMember"
      id="ixv-563">AON</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_us-gaap-CapitalUnitClassAMember"
      id="ixv-564">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs285SeniorNotesDue2027Member"
      id="ixv-565">Guarantees of Aon Corporation and Aon Global Holdings plc&#x2019;s 2.850% Senior Notes due 2027</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs285SeniorNotesDue2027Member"
      id="ixv-566">AON27</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs285SeniorNotesDue2027Member"
      id="ixv-567">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.050SeniorNotesDue20315Member"
      id="ixv-568">Guarantees of Aon Corporation and Aon Global Holdings plc&#x2019;s 2.050% Senior Notes due 2031</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.050SeniorNotesDue20315Member"
      id="ixv-569">AON31</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.050SeniorNotesDue20315Member"
      id="ixv-570">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.600SeniorNotesDue20311Member"
      id="ixv-571">Guarantees of Aon Corporation and Aon Global Holdings plc&#x2019;s 2.600% Senior Notes due 2031</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.600SeniorNotesDue20311Member"
      id="ixv-572">AON31A</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.600SeniorNotesDue20311Member"
      id="ixv-573">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs5.000SeniorNotesDue20322Member"
      id="ixv-574">Guarantees of Aon Corporation and Aon Global Holdings plc&#x2019;s 5.000% Senior Notes due&#160;2032</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs5.000SeniorNotesDue20322Member"
      id="ixv-575">AON32</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs5.000SeniorNotesDue20322Member"
      id="ixv-576">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs5.350SeniorNotesDue20333Member"
      id="ixv-577">Guarantees of Aon Corporation and Aon Global Holdings plc&#x2019;s 5.350% Senior Notes due 2033</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs5.350SeniorNotesDue20333Member"
      id="ixv-578">AON33</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs5.350SeniorNotesDue20333Member"
      id="ixv-579">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.250SeniorNotesDue20429Member"
      id="ixv-580">Guarantees of Aon plc&#x2019;s 4.250% Senior Notes due&#160;2042</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.250SeniorNotesDue20429Member"
      id="ixv-581">AON42</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.250SeniorNotesDue20429Member"
      id="ixv-582">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.450SeniorNotesDue20436Member"
      id="ixv-583">Guarantees of Aon plc&#x2019;s 4.450% Senior Notes due&#160;2043</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.450SeniorNotesDue20436Member"
      id="ixv-584">AON43</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.450SeniorNotesDue20436Member"
      id="ixv-585">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.600SeniorNotesDue20447Member"
      id="ixv-586">Guarantees of Aon plc&#x2019;s 4.600% Senior Notes due&#160;2044</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.600SeniorNotesDue20447Member"
      id="ixv-587">AON44</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.600SeniorNotesDue20447Member"
      id="ixv-588">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.750SeniorNotesDue20458Member"
      id="ixv-589">Guarantees of Aon plc&#x2019;s 4.750% Senior Notes due&#160;2045</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.750SeniorNotesDue20458Member"
      id="ixv-590">AON45</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonPlcs4.750SeniorNotesDue20458Member"
      id="ixv-591">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.900SeniorNotesDue20514Member"
      id="ixv-592">Guarantees of Aon Corporation and Aon Global Holdings plc&#x2019;s 2.900% Senior Notes due&#160;2051</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.900SeniorNotesDue20514Member"
      id="ixv-593">AON51</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs2.900SeniorNotesDue20514Member"
      id="ixv-594">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs390SeniorNotesDue2052Member"
      id="ixv-595">Guarantees of Aon Corporation and Aon Global Holdings plc&#x2019;s 3.900% Senior Notes due 2052</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs390SeniorNotesDue2052Member"
      id="ixv-596">AON52</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonCorporationAndAonGlobalHoldingsPlcs390SeniorNotesDue2052Member"
      id="ixv-597">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.125SeniorNotesDue2027Member"
      id="ixv-598">Guarantees of Aon North America, Inc.&#x2019;s 5.125% Senior Notes due 2027</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.125SeniorNotesDue2027Member"
      id="ixv-599">AON27B</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.125SeniorNotesDue2027Member"
      id="ixv-600">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.150SeniorNotesDue2029Member"
      id="ixv-601">Guarantees of Aon North America, Inc.&#x2019;s 5.150% Senior Notes due 2029</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.150SeniorNotesDue2029Member"
      id="ixv-602">AON29</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.150SeniorNotesDue2029Member"
      id="ixv-603">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.300SeniorNotesDue2031Member"
      id="ixv-604">Guarantees of Aon North America, Inc.&#x2019;s 5.300% Senior Notes due 2031</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.300SeniorNotesDue2031Member"
      id="ixv-605">AON31B</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.300SeniorNotesDue2031Member"
      id="ixv-606">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.450SeniorNotesDue2034Member"
      id="ixv-607">Guarantees of Aon North America, Inc.&#x2019;s 5.450% Senior Notes due 2034</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.450SeniorNotesDue2034Member"
      id="ixv-608">AON34</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.450SeniorNotesDue2034Member"
      id="ixv-609">NYSE</dei:SecurityExchangeName>
    <dei:Security12bTitle
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.750SeniorNotesDue2054Member"
      id="ixv-610">Guarantees of Aon North America, Inc.&#x2019;s 5.750% Senior Notes due 2054</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.750SeniorNotesDue2054Member"
      id="ixv-611">AON54</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="duration_2026-08-30_to_2026-08-30_us-gaap-StatementClassOfStockAxis_aon-GuaranteesOfAonNorthAmericaInc.s5.750SeniorNotesDue2054Member"
      id="ixv-612">NYSE</dei:SecurityExchangeName>
    <dei:EntityEmergingGrowthCompany contextRef="duration_2026-08-30_to_2026-08-30" id="ixv-613">false</dei:EntityEmergingGrowthCompany>
</xbrl>
