<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.24.0.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>210</ContextCount>
  <ElementCount>303</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>63</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>6</UnitCount>
  <MyReports>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>100000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>100010 - Statement - STATEMENTS OF INCOME</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_StatementSTATEMENTSOFINCOME</Role>
      <ShortName>STATEMENTS OF INCOME</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>100030 - Statement - STATEMENTS OF COMPREHENSIVE INCOME</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_StatementSTATEMENTSOFCOMPREHENSIVEINCOME</Role>
      <ShortName>STATEMENTS OF COMPREHENSIVE INCOME</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>100040 - Statement - BALANCE SHEETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_StatementBALANCESHEETS</Role>
      <ShortName>BALANCE SHEETS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>100050 - Statement - BALANCE SHEETS (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_StatementBALANCESHEETSParenthetical</Role>
      <ShortName>BALANCE SHEETS (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>100060 - Statement - STATEMENTS OF CASH FLOWS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_StatementSTATEMENTSOFCASHFLOWS</Role>
      <ShortName>STATEMENTS OF CASH FLOWS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>100070 - Statement - STATEMENTS OF STOCKHOLDER'S EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_StatementSTATEMENTSOFSTOCKHOLDERSEQUITY</Role>
      <ShortName>STATEMENTS OF STOCKHOLDER'S EQUITY</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>100080 - Statement - STATEMENTS OF STOCKHOLDER'S EQUITY (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_StatementSTATEMENTSOFSTOCKHOLDERSEQUITYParenthetical</Role>
      <ShortName>STATEMENTS OF STOCKHOLDER'S EQUITY (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>995410 - Disclosure - Pay vs Performance Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/PvpDisclosure</Role>
      <ShortName>Pay vs Performance Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>995445 - Disclosure - Insider Trading Arrangements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements</Role>
      <ShortName>Insider Trading Arrangements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>995455 - Disclosure - Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureSignificantAccountingPolicies</Role>
      <ShortName>Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>995465 - Disclosure - Finance and Other Receivables</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureFinanceAndOtherReceivables</Role>
      <ShortName>Finance and Other Receivables</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>995475 - Disclosure - Equipment On Operating Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureEquipmentOnOperatingLeases</Role>
      <ShortName>Equipment On Operating Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>995485 - Disclosure - Transactions with PACCAR and Affiliates</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureTransactionsWithPACCARAndAffiliates</Role>
      <ShortName>Transactions with PACCAR and Affiliates</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>995495 - Disclosure - Stockholder's Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureStockholderSEquity</Role>
      <ShortName>Stockholder's Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>995505 - Disclosure - Derivative Financial Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureDerivativeFinancialInstruments</Role>
      <ShortName>Derivative Financial Instruments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>995515 - Disclosure - Borrowings</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureBorrowings</Role>
      <ShortName>Borrowings</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>995525 - Disclosure - Credit Arrangements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureCreditArrangements</Role>
      <ShortName>Credit Arrangements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>995535 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureIncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>995545 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureFairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>995555 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>995565 - Disclosure - Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureSignificantAccountingPolicies</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>995575 - Disclosure - Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureSignificantAccountingPoliciesTables</Role>
      <ShortName>Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureSignificantAccountingPolicies</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>995585 - Disclosure - Finance and Other Receivables (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureFinanceAndOtherReceivablesTables</Role>
      <ShortName>Finance and Other Receivables (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureFinanceAndOtherReceivables</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>995595 - Disclosure - Transactions with PACCAR and Affiliates (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureTransactionsWithPACCARAndAffiliatesTables</Role>
      <ShortName>Transactions with PACCAR and Affiliates (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureTransactionsWithPACCARAndAffiliates</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>995605 - Disclosure - Stockholder's Equity (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureStockholderSEquityTables</Role>
      <ShortName>Stockholder's Equity (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureStockholderSEquity</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>995615 - Disclosure - Derivative Financial Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureDerivativeFinancialInstrumentsTables</Role>
      <ShortName>Derivative Financial Instruments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureDerivativeFinancialInstruments</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>995625 - Disclosure - Borrowings (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureBorrowingsTables</Role>
      <ShortName>Borrowings (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureBorrowings</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>995635 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureIncomeTaxesTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureIncomeTaxes</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>995645 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureFairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureFairValueMeasurements</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>995655 - Disclosure - Significant Accounting Policies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureSignificantAccountingPoliciesAdditionalInformationDetail</Role>
      <ShortName>Significant Accounting Policies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>995665 - Disclosure - The Company Adopted Standards (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureTheCompanyAdoptedStandardsDetail</Role>
      <ShortName>The Company Adopted Standards (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>995675 - Disclosure - Finance and Other Receivables (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureFinanceAndOtherReceivablesDetail</Role>
      <ShortName>Finance and Other Receivables (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureFinanceAndOtherReceivablesTables</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>995685 - Disclosure - Annual Minimum Payments Due on Finance Leases and Reconciliation of Undiscounted Cash Flows to Amortized Cost Basis of Finance Leases (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureAnnualMinimumPaymentsDueOnFinanceLeasesAndReconciliationOfUndiscountedCashFlowsToAmortizedCostBasisOfFinanceLeasesDetail</Role>
      <ShortName>Annual Minimum Payments Due on Finance Leases and Reconciliation of Undiscounted Cash Flows to Amortized Cost Basis of Finance Leases (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>995705 - Disclosure - Finance and Other Receivables - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureFinanceAndOtherReceivablesAdditionalInformationDetail</Role>
      <ShortName>Finance and Other Receivables - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>995715 - Disclosure - Allowance for Credit Losses (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureAllowanceForCreditLossesDetail</Role>
      <ShortName>Allowance for Credit Losses (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>995725 - Disclosure - Finance Receivables within Credit Quality Indicator and Portfolio Class (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/DisclosureFinanceReceivablesWithinCreditQualityIndicatorAndPortfolioClassDetail</Role>
      <ShortName>Finance Receivables within Credit Quality Indicator and Portfolio Class (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>995735 - Disclosure - Summary of Amortized Cost Basis of Financing Receivables by Aging Category (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureSummaryOfAmortizedCostBasisOfFinancingReceivablesByAgingCategoryDetail</Role>
      <ShortName>Summary of Amortized Cost Basis of Financing Receivables by Aging Category (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>995745 - Disclosure - Amortized Cost Basis for Finance Receivables that are on Non-accrual Status (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureAmortizedCostBasisForFinanceReceivablesThatAreOnNonAccrualStatusDetail</Role>
      <ShortName>Amortized Cost Basis for Finance Receivables that are on Non-accrual Status (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>995755 - Disclosure - Interest Income Recognized on Cash Basis for Finance Receivables that are on Non-accrual Status (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureInterestIncomeRecognizedOnCashBasisForFinanceReceivablesThatAreOnNonAccrualStatusDetail</Role>
      <ShortName>Interest Income Recognized on Cash Basis for Finance Receivables that are on Non-accrual Status (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>995765 - Disclosure - Pre-Modification and Post-Modification Amortized Cost Basis (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosurePreModificationAndPostModificationAmortizedCostBasisDetail</Role>
      <ShortName>Pre-Modification and Post-Modification Amortized Cost Basis (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>995775 - Disclosure - Equipment on Operating Leases - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureEquipmentOnOperatingLeasesAdditionalInformationDetail</Role>
      <ShortName>Equipment on Operating Leases - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>995785 - Disclosure - Transactions with PACCAR and Affiliates - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureTransactionsWithPACCARAndAffiliatesAdditionalInformationDetail</Role>
      <ShortName>Transactions with PACCAR and Affiliates - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>995795 - Disclosure - Amounts Outstanding Including Foreign Finance Affiliates (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureAmountsOutstandingIncludingForeignFinanceAffiliatesDetail</Role>
      <ShortName>Amounts Outstanding Including Foreign Finance Affiliates (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>995805 - Disclosure - Stockholder's Equity - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureStockholderSEquityAdditionalInformationDetail</Role>
      <ShortName>Stockholder's Equity - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>995815 - Disclosure - Changes in and Reclassifications out of Accumulated Other Comprehensive Loss (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureChangesInAndReclassificationsOutOfAccumulatedOtherComprehensiveLossDetail</Role>
      <ShortName>Changes in and Reclassifications out of Accumulated Other Comprehensive Loss (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>995825 - Disclosure - Derivative Financial Instruments - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureDerivativeFinancialInstrumentsAdditionalInformationDetail</Role>
      <ShortName>Derivative Financial Instruments - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>995835 - Disclosure - Balance Sheet Classification, Fair Value and Gross and Net Amounts of Derivative Financial Instruments (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureBalanceSheetClassificationFairValueAndGrossAndNetAmountsOfDerivativeFinancialInstrumentsDetail</Role>
      <ShortName>Balance Sheet Classification, Fair Value and Gross and Net Amounts of Derivative Financial Instruments (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>995845 - Disclosure - Amounts Recorded on Balance Sheets Related to Cumulative Basis Adjustments for Fair Value Hedges (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureAmountsRecordedOnBalanceSheetsRelatedToCumulativeBasisAdjustmentsForFairValueHedgesDetail</Role>
      <ShortName>Amounts Recorded on Balance Sheets Related to Cumulative Basis Adjustments for Fair Value Hedges (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>995855 - Disclosure - Amount of (Income) Expense on Cash Flow and Fair Value Hedges Recognized in Interest and Other Borrowing Costs on Statements of Income (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/DisclosureAmountOfIncomeExpenseOnCashFlowAndFairValueHedgesRecognizedInInterestAndOtherBorrowingCostsOnStatementsOfIncomeDetail</Role>
      <ShortName>Amount of (Income) Expense on Cash Flow and Fair Value Hedges Recognized in Interest and Other Borrowing Costs on Statements of Income (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>995865 - Disclosure - Summary of Borrowings (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureSummaryOfBorrowingsDetail</Role>
      <ShortName>Summary of Borrowings (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>995875 - Disclosure - Borrowings - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureBorrowingsAdditionalInformationDetail</Role>
      <ShortName>Borrowings - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>995885 - Disclosure - Annual Maturities of Borrowings (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureAnnualMaturitiesOfBorrowingsDetail</Role>
      <ShortName>Annual Maturities of Borrowings (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>995895 - Disclosure - Credit Arrangements - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureCreditArrangementsAdditionalInformationDetail</Role>
      <ShortName>Credit Arrangements - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>995905 - Disclosure - Income Taxes - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureIncomeTaxesAdditionalInformationDetail</Role>
      <ShortName>Income Taxes - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>995915 - Disclosure - Components of Provision for Income Taxes (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureComponentsOfProvisionForIncomeTaxesDetail</Role>
      <ShortName>Components of Provision for Income Taxes (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>995925 - Disclosure - Reconciliation of Statutory U.S. Federal Tax Rate to the Effective Income Tax Rates (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureReconciliationOfStatutoryUSFederalTaxRateToEffectiveIncomeTaxRatesDetail</Role>
      <ShortName>Reconciliation of Statutory U.S. Federal Tax Rate to the Effective Income Tax Rates (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>995935 - Disclosure - Deferred Tax Assets and Liabilities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureDeferredTaxAssetsAndLiabilitiesDetail</Role>
      <ShortName>Deferred Tax Assets and Liabilities (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>995945 - Disclosure - Assets and Liabilities Fair Value Measurements (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureAssetsAndLiabilitiesFairValueMeasurementsDetail</Role>
      <ShortName>Assets and Liabilities Fair Value Measurements (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>995965 - Disclosure - Fair Value Measurements - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureFairValueMeasurementsAdditionalInformationDetail</Role>
      <ShortName>Fair Value Measurements - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>995975 - Disclosure - Carrying Amount and Fair Value for Fixed-Rate Loans and Debt (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureCarryingAmountAndFairValueForFixedRateLoansAndDebtDetail</Role>
      <ShortName>Carrying Amount and Fair Value for Fixed-Rate Loans and Debt (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="pcar-20231231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>995985 - Disclosure - Commitments and Contingencies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.paccarfinancial.com/20231231/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesAdditionalInformationDetail</Role>
      <ShortName>Commitments and Contingencies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-K" isDefinitelyFs="true" isUsgaap="true" original="pcar-20231231.htm">pcar-20231231.htm</File>
    <File>pcar-20231231.xsd</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="824">http://fasb.org/us-gaap/2023</BaseTaxonomy>
    <BaseTaxonomy items="38">http://xbrl.sec.gov/dei/2023</BaseTaxonomy>
    <BaseTaxonomy items="4">http://xbrl.sec.gov/ecd/2023</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>false</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
