<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>249</ContextCount>
  <ElementCount>191</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>53</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>5</UnitCount>
  <MyReports>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0000001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>9952151 - Statement - Consolidated Statements of Earnings</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/ConsolidatedStatementsofEarnings</Role>
      <ShortName>Consolidated Statements of Earnings</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>9952152 - Statement - Consolidated Statements of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/ConsolidatedStatementsofComprehensiveIncome</Role>
      <ShortName>Consolidated Statements of Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>9952153 - Statement - Consolidated Statements of Comprehensive Income (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/ConsolidatedStatementsofComprehensiveIncomeParenthetical</Role>
      <ShortName>Consolidated Statements of Comprehensive Income (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>9952154 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/ConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>9952155 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/ConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>9952156 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/ConsolidatedStatementsofCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>9952157 - Statement - Consolidated Statements of Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/ConsolidatedStatementsofEquity</Role>
      <ShortName>Consolidated Statements of Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>9952158 - Statement - Consolidated Statements of Equity (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/ConsolidatedStatementsofEquityParenthetical</Role>
      <ShortName>Consolidated Statements of Equity (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>9952159 - Disclosure - BASIS OF PRESENTATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/BASISOFPRESENTATION</Role>
      <ShortName>BASIS OF PRESENTATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>9952160 - Disclosure - EARNINGS PER COMMON SHARE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/EARNINGSPERCOMMONSHARE</Role>
      <ShortName>EARNINGS PER COMMON SHARE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>9952161 - Disclosure - INFORMATION ON BUSINESS SEGMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/INFORMATIONONBUSINESSSEGMENTS</Role>
      <ShortName>INFORMATION ON BUSINESS SEGMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>9952162 - Disclosure - CONTRACT ASSETS AND LIABILITIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/CONTRACTASSETSANDLIABILITIES</Role>
      <ShortName>CONTRACT ASSETS AND LIABILITIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>9952163 - Disclosure - INVENTORIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/INVENTORIES</Role>
      <ShortName>INVENTORIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>9952164 - Disclosure - RETIREMENT BENEFITS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/RETIREMENTBENEFITS</Role>
      <ShortName>RETIREMENT BENEFITS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>9952165 - Disclosure - LEGAL PROCEEDINGS AND CONTINGENCIES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/LEGALPROCEEDINGSANDCONTINGENCIES</Role>
      <ShortName>LEGAL PROCEEDINGS AND CONTINGENCIES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>9952166 - Disclosure - FAIR VALUE MEASUREMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/FAIRVALUEMEASUREMENTS</Role>
      <ShortName>FAIR VALUE MEASUREMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>9952167 - Disclosure - STOCKHOLDERS' EQUITY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/STOCKHOLDERSEQUITY</Role>
      <ShortName>STOCKHOLDERS' EQUITY</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>9952168 - Disclosure - OTHER</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/OTHER</Role>
      <ShortName>OTHER</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>9952169 - Disclosure - RECENT ACCOUNTING PRONOUNCEMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/RECENTACCOUNTINGPRONOUNCEMENTS</Role>
      <ShortName>RECENT ACCOUNTING PRONOUNCEMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.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>21</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>9955511 - Disclosure - RECENT ACCOUNTING PRONOUNCEMENTS (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/RECENTACCOUNTINGPRONOUNCEMENTSPolicies</Role>
      <ShortName>RECENT ACCOUNTING PRONOUNCEMENTS (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>9955512 - Disclosure - EARNINGS PER COMMON SHARE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/EARNINGSPERCOMMONSHARETables</Role>
      <ShortName>EARNINGS PER COMMON SHARE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lockheedmartin.com/role/EARNINGSPERCOMMONSHARE</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>9955513 - Disclosure - INFORMATION ON BUSINESS SEGMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/INFORMATIONONBUSINESSSEGMENTSTables</Role>
      <ShortName>INFORMATION ON BUSINESS SEGMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lockheedmartin.com/role/INFORMATIONONBUSINESSSEGMENTS</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>9955514 - Disclosure - CONTRACT ASSETS AND LIABILITIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/CONTRACTASSETSANDLIABILITIESTables</Role>
      <ShortName>CONTRACT ASSETS AND LIABILITIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lockheedmartin.com/role/CONTRACTASSETSANDLIABILITIES</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>9955515 - Disclosure - INVENTORIES (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/INVENTORIESTables</Role>
      <ShortName>INVENTORIES (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lockheedmartin.com/role/INVENTORIES</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>9955516 - Disclosure - RETIREMENT BENEFITS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/RETIREMENTBENEFITSTables</Role>
      <ShortName>RETIREMENT BENEFITS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lockheedmartin.com/role/RETIREMENTBENEFITS</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>9955517 - Disclosure - FAIR VALUE MEASUREMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/FAIRVALUEMEASUREMENTSTables</Role>
      <ShortName>FAIR VALUE MEASUREMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lockheedmartin.com/role/FAIRVALUEMEASUREMENTS</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>9955518 - Disclosure - STOCKHOLDERS' EQUITY (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/STOCKHOLDERSEQUITYTables</Role>
      <ShortName>STOCKHOLDERS' EQUITY (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lockheedmartin.com/role/STOCKHOLDERSEQUITY</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>9955519 - Disclosure - OTHER (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/OTHERTables</Role>
      <ShortName>OTHER (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lockheedmartin.com/role/OTHER</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>9955520 - Disclosure - EARNINGS PER COMMON SHARE - Schedule of Weighted Average Shares Outstanding Used to Compute Earnings Per Common Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/EARNINGSPERCOMMONSHAREScheduleofWeightedAverageSharesOutstandingUsedtoComputeEarningsPerCommonShareDetails</Role>
      <ShortName>EARNINGS PER COMMON SHARE - Schedule of Weighted Average Shares Outstanding Used to Compute Earnings Per Common Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>9955521 - Disclosure - EARNINGS PER COMMON SHARE - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/EARNINGSPERCOMMONSHARENarrativeDetails</Role>
      <ShortName>EARNINGS PER COMMON SHARE - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>9955522 - Disclosure - INFORMATION ON BUSINESS SEGMENTS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/INFORMATIONONBUSINESSSEGMENTSNarrativeDetails</Role>
      <ShortName>INFORMATION ON BUSINESS SEGMENTS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>9955523 - Disclosure - INFORMATION ON BUSINESS SEGMENTS - Schedule of Financial Information for Each Business Segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/INFORMATIONONBUSINESSSEGMENTSScheduleofFinancialInformationforEachBusinessSegmentDetails</Role>
      <ShortName>INFORMATION ON BUSINESS SEGMENTS - Schedule of Financial Information for Each Business Segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>9955524 - Disclosure - INFORMATION ON BUSINESS SEGMENTS - Schedule of FAS/CAS Pension Adjustment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/INFORMATIONONBUSINESSSEGMENTSScheduleofFASCASPensionAdjustmentDetails</Role>
      <ShortName>INFORMATION ON BUSINESS SEGMENTS - Schedule of FAS/CAS Pension Adjustment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>9955525 - Disclosure - INFORMATION ON BUSINESS SEGMENTS - Schedule of Income Statement Information For Each Segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/INFORMATIONONBUSINESSSEGMENTSScheduleofIncomeStatementInformationForEachSegmentDetails</Role>
      <ShortName>INFORMATION ON BUSINESS SEGMENTS - Schedule of Income Statement Information For Each Segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>9955526 - Disclosure - INFORMATION ON BUSINESS SEGMENTS - Schedule of Total Assets and Customer Advances and Amounts In Excess Of Costs Incurred For Each Business Segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/INFORMATIONONBUSINESSSEGMENTSScheduleofTotalAssetsandCustomerAdvancesandAmountsInExcessOfCostsIncurredForEachBusinessSegmentDetails</Role>
      <ShortName>INFORMATION ON BUSINESS SEGMENTS - Schedule of Total Assets and Customer Advances and Amounts In Excess Of Costs Incurred For Each Business Segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>9955527 - Disclosure - CONTRACT ASSETS AND LIABILITIES - Schedule of Contract Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/CONTRACTASSETSANDLIABILITIESScheduleofContractAssetsandLiabilitiesDetails</Role>
      <ShortName>CONTRACT ASSETS AND LIABILITIES - Schedule of Contract Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>9955528 - Disclosure - CONTRACT ASSETS AND LIABILITIES - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/CONTRACTASSETSANDLIABILITIESNarrativeDetails</Role>
      <ShortName>CONTRACT ASSETS AND LIABILITIES - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>9955529 - Disclosure - Inventories - Schedule of Inventories (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/InventoriesScheduleofInventoriesDetails</Role>
      <ShortName>Inventories - Schedule of Inventories (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>9955530 - Disclosure - Inventories - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/InventoriesNarrativeDetails</Role>
      <ShortName>Inventories - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>9955531 - Disclosure - RETIREMENT BENEFITS - Schedule of Net Periodic Benefit Costs (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/RETIREMENTBENEFITSScheduleofNetPeriodicBenefitCostsDetails</Role>
      <ShortName>RETIREMENT BENEFITS - Schedule of Net Periodic Benefit Costs (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>9955532 - Disclosure - RETIREMENT BENEFITS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/RETIREMENTBENEFITSNarrativeDetails</Role>
      <ShortName>RETIREMENT BENEFITS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>9955533 - Disclosure - LEGAL PROCEEDINGS AND CONTINGENCIES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/LEGALPROCEEDINGSANDCONTINGENCIESDetails</Role>
      <ShortName>LEGAL PROCEEDINGS AND CONTINGENCIES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.lockheedmartin.com/role/LEGALPROCEEDINGSANDCONTINGENCIES</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>9955534 - Disclosure - FAIR VALUE MEASUREMENTS - Schedule of Assets and Liabilities Measured and Recorded at Fair Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/FAIRVALUEMEASUREMENTSScheduleofAssetsandLiabilitiesMeasuredandRecordedatFairValueDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS - Schedule of Assets and Liabilities Measured and Recorded at Fair Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>9955535 - Disclosure - FAIR VALUE MEASUREMENTS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/FAIRVALUEMEASUREMENTSNarrativeDetails</Role>
      <ShortName>FAIR VALUE MEASUREMENTS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>9955536 - Disclosure - STOCKHOLDERS' EQUITY - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/STOCKHOLDERSEQUITYNarrativeDetails</Role>
      <ShortName>STOCKHOLDERS' EQUITY - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>9955537 - Disclosure - STOCKHOLDERS' EQUITY - Schedule of Changes in Balance of Accumulated Other Comprehensive Loss, Net of Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/STOCKHOLDERSEQUITYScheduleofChangesinBalanceofAccumulatedOtherComprehensiveLossNetofIncomeTaxesDetails</Role>
      <ShortName>STOCKHOLDERS' EQUITY - Schedule of Changes in Balance of Accumulated Other Comprehensive Loss, Net of Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>9955538 - Disclosure - OTHER - Schedule of Contract Estimates Consolidated Net Profit Booking Rate Adjustments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/OTHERScheduleofContractEstimatesConsolidatedNetProfitBookingRateAdjustmentsDetails</Role>
      <ShortName>OTHER - Schedule of Contract Estimates Consolidated Net Profit Booking Rate Adjustments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>9955539 - Disclosure - OTHER - Schedule of Contract Estimates (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/OTHERScheduleofContractEstimatesDetails</Role>
      <ShortName>OTHER - Schedule of Contract Estimates (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>9955540 - Disclosure - OTHER - Schedule of Backlog (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/OTHERScheduleofBacklogDetails</Role>
      <ShortName>OTHER - Schedule of Backlog (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="lmt-20260329.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>9955541 - Disclosure - OTHER - Schedule of Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lockheedmartin.com/role/OTHERScheduleofIncomeTaxesDetails</Role>
      <ShortName>OTHER - Schedule of Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</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-Q" isDefinitelyFs="true" isUsgaap="true" original="lmt-20260329.htm">lmt-20260329.htm</File>
    <File>lmt-20260329.xsd</File>
    <File>lmt-20260329_cal.xml</File>
    <File>lmt-20260329_def.xml</File>
    <File>lmt-20260329_lab.xml</File>
    <File>lmt-20260329_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="571">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="29">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="4">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
