<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>3922</ContextCount>
  <ElementCount>94</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>20</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>6</UnitCount>
  <MyReports>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Cover</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/Cover</Role>
      <ShortName>Cover</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>0000002 - Statement - STATEMENTS OF NET ASSETS AVAILABLE FOR BENEFITS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/STATEMENTSOFNETASSETSAVAILABLEFORBENEFITS</Role>
      <ShortName>STATEMENTS OF NET ASSETS AVAILABLE FOR BENEFITS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>0000003 - Statement - STATEMENT OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/STATEMENTOFCHANGESINNETASSETSAVAILABLEFORBENEFITS</Role>
      <ShortName>STATEMENT OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>0000004 - Disclosure - DESCRIPTION OF THE PLAN</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/DESCRIPTIONOFTHEPLAN</Role>
      <ShortName>DESCRIPTION OF THE PLAN</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>0000005 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIES</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>0000006 - Disclosure - FAIR VALUE MEASUREMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/FAIRVALUEMEASUREMENTS</Role>
      <ShortName>FAIR VALUE MEASUREMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>0000007 - Disclosure - PARTY-IN-INTEREST</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/PARTYININTEREST</Role>
      <ShortName>PARTY-IN-INTEREST</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>0000008 - Disclosure - INCOME TAX STATUS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/INCOMETAXSTATUS</Role>
      <ShortName>INCOME TAX STATUS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>0000009 - Disclosure - RISKS AND UNCERTAINTIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/RISKSANDUNCERTAINTIES</Role>
      <ShortName>RISKS AND UNCERTAINTIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>0000010 - Disclosure - RECONCILIATION OF FINANCIAL STATEMENTS AND FORM 5500</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/RECONCILIATIONOFFINANCIALSTATEMENTSANDFORM5500</Role>
      <ShortName>RECONCILIATION OF FINANCIAL STATEMENTS AND FORM 5500</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>0000011 - Disclosure - SUBSEQUENT EVENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/SUBSEQUENTEVENTS</Role>
      <ShortName>SUBSEQUENT EVENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>0000012 - Disclosure - Schedule H, Line 4i – Schedule of Assets (Held At End of Year)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/ScheduleHLine4iScheduleofAssetsHeldAtEndofYear</Role>
      <ShortName>Schedule H, Line 4i – Schedule of Assets (Held At End of Year)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>0000013 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>0000014 - Disclosure - FAIR VALUE MEASUREMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/FAIRVALUEMEASUREMENTSTables</Role>
      <ShortName>FAIR VALUE MEASUREMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.marriott.com/role/FAIRVALUEMEASUREMENTS</ParentRole>
      <Position>14</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>0000015 - Disclosure - RECONCILIATION OF FINANCIAL STATEMENTS AND FORM 5500 (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/RECONCILIATIONOFFINANCIALSTATEMENTSANDFORM5500Tables</Role>
      <ShortName>RECONCILIATION OF FINANCIAL STATEMENTS AND FORM 5500 (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.marriott.com/role/RECONCILIATIONOFFINANCIALSTATEMENTSANDFORM5500</ParentRole>
      <Position>15</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>0000016 - Disclosure - DESCRIPTION OF THE PLAN (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/DESCRIPTIONOFTHEPLANDetails</Role>
      <ShortName>DESCRIPTION OF THE PLAN (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.marriott.com/role/DESCRIPTIONOFTHEPLAN</ParentRole>
      <Position>16</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>0000017 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESDetails</Role>
      <ShortName>SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.marriott.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESPolicies</ParentRole>
      <Position>17</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>0000018 - Disclosure - FAIR VALUE MEASUREMENTS - Investments Measured at Fair Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/FAIRVALUEMEASUREMENTSInvestmentsMeasuredatFairValueDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS - Investments Measured at Fair Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>0000019 - Disclosure - FAIR VALUE MEASUREMENTS - NAV (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/FAIRVALUEMEASUREMENTSNAVDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS - NAV (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>0000020 - Disclosure - PARTY-IN-INTEREST (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/PARTYININTERESTDetails</Role>
      <ShortName>PARTY-IN-INTEREST (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.marriott.com/role/PARTYININTEREST</ParentRole>
      <Position>20</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>0000021 - Disclosure - RECONCILIATION OF FINANCIAL STATEMENTS AND FORM 5500 - Reconciliation of Net Assets Available for Benefit (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/RECONCILIATIONOFFINANCIALSTATEMENTSANDFORM5500ReconciliationofNetAssetsAvailableforBenefitDetails</Role>
      <ShortName>RECONCILIATION OF FINANCIAL STATEMENTS AND FORM 5500 - Reconciliation of Net Assets Available for Benefit (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>0000022 - Disclosure - RECONCILIATION OF FINANCIAL STATEMENTS AND FORM 5500 - Reconciliation of Benefits Paid To Participants (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/RECONCILIATIONOFFINANCIALSTATEMENTSANDFORM5500ReconciliationofBenefitsPaidToParticipantsDetails</Role>
      <ShortName>RECONCILIATION OF FINANCIAL STATEMENTS AND FORM 5500 - Reconciliation of Benefits Paid To Participants (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>0000023 - Disclosure - RECONCILIATION OF FINANCIAL STATEMENTS AND FORM 5500 - Reconciliation Of Notes Receivable From Participants (Details)</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.marriott.com/role/RECONCILIATIONOFFINANCIALSTATEMENTSANDFORM5500ReconciliationOfNotesReceivableFromParticipantsDetails</Role>
      <ShortName>RECONCILIATION OF FINANCIAL STATEMENTS AND FORM 5500 - Reconciliation Of Notes Receivable From Participants (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>0000024 - Disclosure - RECONCILIATION OF FINANCIAL STATEMENTS AND FORM 5500 - Reconciliation Of The Change In Net Assets Available For Benefits (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/RECONCILIATIONOFFINANCIALSTATEMENTSANDFORM5500ReconciliationOfTheChangeInNetAssetsAvailableForBenefitsDetails</Role>
      <ShortName>RECONCILIATION OF FINANCIAL STATEMENTS AND FORM 5500 - Reconciliation Of The Change In Net Assets Available For Benefits (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="mar-20260616.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>0000025 - Disclosure - Schedule H, Line 4i – Schedule of Assets (Held At End of Year) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.marriott.com/role/ScheduleHLine4iScheduleofAssetsHeldAtEndofYearDetails</Role>
      <ShortName>Schedule H, Line 4i – Schedule of Assets (Held At End of Year) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.marriott.com/role/ScheduleHLine4iScheduleofAssetsHeldAtEndofYear</ParentRole>
      <Position>25</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="11-K" isDefinitelyFs="true" isUsgaap="true" original="mar-20260616.htm">mar-20260616.htm</File>
    <File>mar-20260616.xsd</File>
    <File>mar-20260616_cal.xml</File>
    <File>mar-20260616_def.xml</File>
    <File>mar-20260616_lab.xml</File>
    <File>mar-20260616_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="6142">http://fasb.org/us-gaap-ebp/2026</BaseTaxonomy>
    <BaseTaxonomy items="9">http://xbrl.sec.gov/dei/2026</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
