<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2026"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef xlink:href="psn-20261028.xsd" xlink:type="simple"/>
    <context id="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000275880</identifier>
        </entity>
        <period>
            <startDate>2026-10-28</startDate>
            <endDate>2026-10-28</endDate>
        </period>
    </context>
    <dei:EntityCentralIndexKey
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_c91a08e2-11b2-403a-b31d-58a0e24738d0">0000275880</dei:EntityCentralIndexKey>
    <dei:AmendmentFlag
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_62072049-9a41-47ab-beae-e3b6d165899c">false</dei:AmendmentFlag>
    <dei:DocumentType
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_96c8a39f-081f-4d86-9317-7c123ee6b6bd">8-K</dei:DocumentType>
    <dei:DocumentPeriodEndDate
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_a9384e25-03e9-4161-ba93-d95daca3c8cc">2026-10-28</dei:DocumentPeriodEndDate>
    <dei:EntityRegistrantName
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_2a27b206-c619-42fb-8b00-04bb26e4c261">Parsons Corporation</dei:EntityRegistrantName>
    <dei:EntityIncorporationStateCountryCode
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_765825da-fcf7-469a-872d-b0daadc12ad2">DE</dei:EntityIncorporationStateCountryCode>
    <dei:EntityFileNumber
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_54b1da5b-df82-45d9-934f-be780641d8c9">001-07782</dei:EntityFileNumber>
    <dei:EntityTaxIdentificationNumber
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_d5cc0184-b033-40ed-bcc2-98445f010ee9">95-3232481</dei:EntityTaxIdentificationNumber>
    <dei:EntityAddressAddressLine1
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_d513a4d6-3a8b-40c0-9a86-c62a11bac7f3">14291 Park Meadow Drive, Suite 100</dei:EntityAddressAddressLine1>
    <dei:EntityAddressCityOrTown
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_ba5aee15-55f3-4c3a-a73b-cf9876b25548">Chantilly</dei:EntityAddressCityOrTown>
    <dei:EntityAddressStateOrProvince
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_fdbb1749-e7bb-4526-a377-778cd0e7d081">VA</dei:EntityAddressStateOrProvince>
    <dei:EntityAddressPostalZipCode
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_23f1acbb-aa62-4b43-b364-2c3bdc7f8523">20151</dei:EntityAddressPostalZipCode>
    <dei:CityAreaCode
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_c98630fa-d2ce-4b1f-8910-aee0ed5bfc34">(703)</dei:CityAreaCode>
    <dei:LocalPhoneNumber
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_16fbe28b-44a1-441e-ac7e-4cb0b2a7ece1">988-8500</dei:LocalPhoneNumber>
    <dei:WrittenCommunications
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_ee4ce20a-a36a-407b-b625-7698d78ea892">false</dei:WrittenCommunications>
    <dei:SolicitingMaterial
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_be9a3a5d-db00-4e22-a658-13aec1d9fe36">false</dei:SolicitingMaterial>
    <dei:PreCommencementTenderOffer
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_c79fe8cf-293f-40c7-a3e9-ac0b80ca0dfd">false</dei:PreCommencementTenderOffer>
    <dei:PreCommencementIssuerTenderOffer
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_1dcdd807-95aa-47b4-8c01-f4820cc6552c">false</dei:PreCommencementIssuerTenderOffer>
    <dei:Security12bTitle
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_d7acd62a-2c3b-4af3-a0df-2d9178bb4478">Common Stock, $1 par value</dei:Security12bTitle>
    <dei:TradingSymbol
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_b79f0813-5451-42ff-beb4-503efc5e5a13">PSN</dei:TradingSymbol>
    <dei:SecurityExchangeName
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_9623e5c8-9c34-45af-99cc-ae74fd4ab6af">NYSE</dei:SecurityExchangeName>
    <dei:EntityEmergingGrowthCompany
      contextRef="C_2a3ccd02-253d-4d12-8695-fe81152e9cfe"
      id="F_85435811-c372-4781-866e-b6dad0a55605">false</dei:EntityEmergingGrowthCompany>
</xbrl>
