<?xml version="1.0" encoding="utf-8"?>
<xbrl
  xmlns="http://www.xbrl.org/2003/instance"
  xmlns:dei="http://xbrl.sec.gov/dei/2026"
  xmlns:iso4217="http://www.xbrl.org/2003/iso4217"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:oef="http://xbrl.sec.gov/oef/2026"
  xmlns:tsr="http://tsr/20260831"
  xmlns:us-gaap="http://fasb.org/us-gaap/2026"
  xmlns:xbrldi="http://xbrl.org/2006/xbrldi"
  xmlns:xhtml="http://www.w3.org/1999/xhtml"
  xmlns:xlink="http://www.w3.org/1999/xlink">
    <link:schemaRef xlink:href="tsr-20260831.xsd" xlink:type="simple"/>
    <context id="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001140869</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">tsr:C000049971Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <startDate>2025-09-01</startDate>
            <endDate>2026-08-31</endDate>
        </period>
    </context>
    <context id="c_8464_instant_LiquidReservesPortfolio_SingleClass_2026-08-31Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001140869</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">tsr:C000049971Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-08-31</instant>
        </period>
    </context>
    <context id="c_8464_instant_LiquidReservesPortfolio_SingleClass_2026-08-31_4123Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001140869</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:InvestmentTypeAxis">tsr:bench202410244123_8464Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:ClassAxis">tsr:C000049971Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-08-31</instant>
        </period>
    </context>
    <context id="c_8464_instant_LiquidReservesPortfolio_SingleClass_2026-08-31_4120Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001140869</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:InvestmentTypeAxis">tsr:bench202410244120_8464Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:ClassAxis">tsr:C000049971Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-08-31</instant>
        </period>
    </context>
    <context id="c_8464_instant_LiquidReservesPortfolio_SingleClass_2026-08-31_4125Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001140869</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:InvestmentTypeAxis">tsr:bench202410244125_8464Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:ClassAxis">tsr:C000049971Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-08-31</instant>
        </period>
    </context>
    <context id="c_8464_instant_LiquidReservesPortfolio_SingleClass_2026-08-31_4122Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001140869</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:InvestmentTypeAxis">tsr:bench202410244122_8464Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:ClassAxis">tsr:C000049971Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-08-31</instant>
        </period>
    </context>
    <context id="c_8464_instant_LiquidReservesPortfolio_SingleClass_2026-08-31_4121Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001140869</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:InvestmentTypeAxis">tsr:bench202410244121_8464Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:ClassAxis">tsr:C000049971Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-08-31</instant>
        </period>
    </context>
    <context id="c_8464_duration_LiquidReservesPortfolio_2025-09-01_2026-08-31Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0001140869</identifier>
        </entity>
        <period>
            <startDate>2025-09-01</startDate>
            <endDate>2026-08-31</endDate>
        </period>
    </context>
    <unit id="USD">
        <measure>iso4217:USD</measure>
    </unit>
    <unit id="RATIO">
        <measure>pure</measure>
    </unit>
    <unit id="UNIT">
        <divide>
            <unitNumerator>
                <measure>iso4217:USD</measure>
            </unitNumerator>
            <unitDenominator>
                <measure>shares</measure>
            </unitDenominator>
        </divide>
    </unit>
    <dei:AmendmentFlag
      contextRef="c_8464_duration_LiquidReservesPortfolio_2025-09-01_2026-08-31Member"
      id="ixv-5054">false</dei:AmendmentFlag>
    <dei:EntityCentralIndexKey
      contextRef="c_8464_duration_LiquidReservesPortfolio_2025-09-01_2026-08-31Member"
      id="ixv-5055">0001140869</dei:EntityCentralIndexKey>
    <dei:EntityRegistrantName
      contextRef="c_8464_duration_LiquidReservesPortfolio_2025-09-01_2026-08-31Member"
      id="ixv-5056">Master Portfolio Trust</dei:EntityRegistrantName>
    <dei:EntityInvCompanyType
      contextRef="c_8464_duration_LiquidReservesPortfolio_2025-09-01_2026-08-31Member"
      id="ixv-5057">N-1A</dei:EntityInvCompanyType>
    <dei:DocumentType
      contextRef="c_8464_duration_LiquidReservesPortfolio_2025-09-01_2026-08-31Member"
      id="ixv-5137">N-CSR</dei:DocumentType>
    <dei:EntityRegistrantName
      contextRef="c_8464_duration_LiquidReservesPortfolio_2025-09-01_2026-08-31Member"
      id="ixv-5138">Master Portfolio Trust</dei:EntityRegistrantName>
    <dei:DocumentPeriodEndDate
      contextRef="c_8464_duration_LiquidReservesPortfolio_2025-09-01_2026-08-31Member"
      id="ixv-5139"
      xml:lang="en-US">2026-08-31</dei:DocumentPeriodEndDate>
    <oef:ClassName
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      id="ixv-85"
      xml:lang="en-US">Liquid Reserves Portfolio</oef:ClassName>
    <oef:FundName
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      id="ixv-86"
      xml:lang="en-US">Liquid Reserves Portfolio</oef:FundName>
    <dei:DocumentPeriodEndDate
      contextRef="c_8464_duration_LiquidReservesPortfolio_2025-09-01_2026-08-31Member"
      id="ixv-95"
      xml:lang="en-US">2026-08-31</dei:DocumentPeriodEndDate>
    <oef:AnnlOrSemiAnnlStatementTextBlock
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      id="ixv-104"
      xml:lang="en-US">&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#161616;;"&gt;This &lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#161616;;"&gt;annual shareholder report&lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#161616;;"&gt; contains important information about &lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#161616;;"&gt;Liquid Reserves Portfolio for the period &lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#161616;;"&gt;September 1, 2025, to &lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#161616;;"&gt;August &lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#161616;;"&gt;31, 2026.&lt;/span&gt;</oef:AnnlOrSemiAnnlStatementTextBlock>
    <oef:ShareholderReportAnnualOrSemiAnnual
      contextRef="c_8464_duration_LiquidReservesPortfolio_2025-09-01_2026-08-31Member"
      id="ixv-106"
      xml:lang="en-US">annual shareholder report</oef:ShareholderReportAnnualOrSemiAnnual>
    <oef:AddlInfoTextBlock
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      id="ixv-114"
      xml:lang="en-US">&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#161616;;"&gt;You can find additional information about the Fund at &lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;;"&gt;https://www.franklintempleton.com/regulatory-masterfunds-documents&lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#161616;;"&gt;. You can &lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#161616;;"&gt;also request this information by contacting us at &lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#161616;;"&gt;1-800-625-4554, or 1-203-703-6002&lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#161616;;"&gt;.&lt;/span&gt;</oef:AddlInfoTextBlock>
    <oef:AddlInfoWebsite
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      id="ixv-116"
      xml:lang="en-US">https://www.franklintempleton.com/regulatory-masterfunds-documents</oef:AddlInfoWebsite>
    <oef:AddlInfoPhoneNumber
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      id="ixv-120"
      xml:lang="en-US">1-800-625-4554, or 1-203-703-6002</oef:AddlInfoPhoneNumber>
    <oef:ExpensesTextBlock
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      id="foot-8464_912687-1011"
      xml:lang="en-US">&lt;div&gt;&lt;span style="text-transform:uppercase;"&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:12.024pt;text-transform:uppercase;color:#1447FF;;"&gt;&lt;b&gt;WHAT WERE THE FUND COSTS FOR THE LAST YEAR? &lt;/b&gt;&lt;/span&gt;&lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.824pt;color:#2D2D2D;;"&gt;(based on a hypothetical $10,000 investment)&lt;/span&gt;&lt;/div&gt;&lt;div&gt;
      &lt;table cellspacing="0" style="width:98%;cellspacing:0;border-top:1.5pt solid #E6FAFF;border-left:1.5pt solid #E6FAFF;  border-right:1.5pt solid #E6FAFF;  border-bottom:1.5pt solid #E6FAFF; margin-left:7.9pt;"&gt;
         &lt;tr style="height:1px;"&gt;
            &lt;td style="height:1px;width:50%;background-color:#E6FAFF;"&gt;&lt;/td&gt;
            &lt;td style="height:1px;width:22.33812949640288%;background-color:#E6FAFF;"&gt;&lt;/td&gt;
            &lt;td style="height:1px;width:27.661870503597125%;background-color:#E6FAFF;"&gt;&lt;/td&gt;
         &lt;/tr&gt;
         &lt;tr&gt;
            &lt;td colspan="1" style="background-color:#E6FAFF;;border-bottom:1.5pt solid #1447FF;vertical-align:bottom"&gt;
               &lt;div style="background-color:#E6FAFF;padding-left:2pt;padding-top:1.5pt;padding-bottom:0;align:left;text-align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;"&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;;"&gt;&lt;b&gt;Fund Name&lt;/b&gt;&lt;/span&gt;&lt;/div&gt;
            &lt;/td&gt;
            &lt;td colspan="1" style="background-color:#E6FAFF;;border-bottom:1.5pt solid #1447FF;vertical-align:bottom"&gt;
               &lt;div style="background-color:#E6FAFF;padding-left:2pt;padding-top:1.5pt;padding-bottom:0;align:center;text-align:center;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;"&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;;"&gt;&lt;b&gt;Costs of a $10,000 &lt;/b&gt;&lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;;"&gt;&lt;b&gt;investment&lt;/b&gt;&lt;/span&gt;&lt;/div&gt;
            &lt;/td&gt;
            &lt;td colspan="1" style="background-color:#E6FAFF;;border-bottom:1.5pt solid #1447FF;vertical-align:bottom"&gt;
               &lt;div style="background-color:#E6FAFF;padding-left:2pt;padding-top:1.5pt;padding-bottom:0;align:center;text-align:center;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;"&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;;"&gt;&lt;b&gt;Costs paid as a percentage of a &lt;/b&gt;&lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;;"&gt;&lt;b&gt;$10,000 investment&lt;/b&gt;&lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;;"&gt;&lt;sup&gt;*&lt;/sup&gt;&lt;/span&gt;
               &lt;/div&gt;
            &lt;/td&gt;
         &lt;/tr&gt;
         &lt;tr&gt;
            &lt;td colspan="1" style="background-color:#E6FAFF;;vertical-align:bottom"&gt;
               &lt;div style="background-color:#E6FAFF;padding-left:2pt;padding-top:1.5pt;padding-bottom:0;align:left;text-align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;"&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;;"&gt;Liquid Reserves Portfolio&lt;/span&gt;&lt;/div&gt;
            &lt;/td&gt;
            &lt;td colspan="1" style="background-color:#E6FAFF;;vertical-align:bottom"&gt;
               &lt;div style="background-color:#E6FAFF;padding-left:2pt;padding-top:1.5pt;padding-bottom:0;align:center;text-align:center;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;"&gt;$1&lt;/span&gt;&lt;/div&gt;
            &lt;/td&gt;
            &lt;td colspan="1" style="background-color:#E6FAFF;;white-space:nowrap;vertical-align:bottom"&gt;
               &lt;div style="background-color:#E6FAFF;padding-left:2pt;padding-top:1.5pt;padding-bottom:0;align:center;text-align:center;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;"&gt;0.01%&lt;/span&gt;&lt;/div&gt;
            &lt;/td&gt;
         &lt;/tr&gt;
      &lt;/table&gt;&lt;/div&gt;</oef:ExpensesTextBlock>
    <oef:ExpensesPaidAmt
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      decimals="INF"
      id="ixv-5140"
      unitRef="USD">1</oef:ExpensesPaidAmt>
    <oef:ExpenseRatioPct
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      decimals="INF"
      id="foot-8464_912687-1021"
      unitRef="RATIO">0.0001</oef:ExpenseRatioPct>
    <oef:AddlFundStatisticsTextBlock
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      id="ixv-184"
      xml:lang="en-US">&lt;div&gt;&lt;span style="text-transform:uppercase;"&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:12.024pt;text-transform:uppercase;color:#1447FF;;"&gt;&lt;b&gt;KEY FUND STATISTICS &lt;/b&gt;&lt;/span&gt;&lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.824pt;color:#2D2D2D;;"&gt;(as of &lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.824pt;color:#2D2D2D;;"&gt;August 31, 2026)&lt;/span&gt;&lt;/div&gt;&lt;div&gt;
      &lt;table cellspacing="0" style="width:98%;cellspacing:0;border-top:1.5pt solid #6B6B6B;margin-left:7.75pt;border-bottom:1.5pt solid #6B6B6B;margin-top:10px;"&gt;
         &lt;tr style="height:1px;"&gt;
            &lt;td style="height:1px;width:74.41007194244604%;"&gt;&lt;/td&gt;
            &lt;td style="height:1px;width:25.58992805755396%;"&gt;&lt;/td&gt;
         &lt;/tr&gt;
         &lt;tr&gt;
            &lt;td colspan="1" style="border-bottom:0.75pt solid #6B6B6B;vertical-align:top"&gt;
               &lt;div style="background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;text-align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;"&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#2D2D2D;;"&gt;&lt;b&gt;Total Net Assets&lt;/b&gt;&lt;/span&gt;&lt;/div&gt;
            &lt;/td&gt;
            &lt;td colspan="1" style="border-bottom:0.75pt solid #6B6B6B;vertical-align:bottom"&gt;
               &lt;div style="background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:right;text-align:right;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;"&gt;$7,929,064,637&lt;/span&gt;&lt;/div&gt;
            &lt;/td&gt;
         &lt;/tr&gt;
         &lt;tr&gt;
            &lt;td colspan="1" style="border-bottom:0.75pt solid #6B6B6B;vertical-align:top"&gt;
               &lt;div style="background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;text-align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;"&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#2D2D2D;;"&gt;&lt;b&gt;Total Number of Portfolio Holdings&lt;/b&gt;&lt;/span&gt;&lt;/div&gt;
            &lt;/td&gt;
            &lt;td colspan="1" style="border-bottom:0.75pt solid #6B6B6B;vertical-align:bottom"&gt;
               &lt;div style="background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:right;text-align:right;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;"&gt;68&lt;/span&gt;&lt;/div&gt;
            &lt;/td&gt;
         &lt;/tr&gt;
         &lt;tr&gt;
            &lt;td colspan="1" style="vertical-align:top"&gt;
               &lt;div style="background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:left;text-align:left;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;"&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;color:#2D2D2D;;"&gt;&lt;b&gt;Total Management Fee Paid&lt;/b&gt;&lt;/span&gt;&lt;/div&gt;
            &lt;/td&gt;
            &lt;td colspan="1" style="vertical-align:bottom"&gt;
               &lt;div style="background-color:#FFFFFF;padding-left:2pt;padding-top:1pt;padding-bottom:0;align:right;text-align:right;padding-right:2pt;font-family:Arial, Helvetica, sans-serif;font-size:10pt;margin-top:1pt;margin-bottom:0;"&gt;&lt;span style="font-family:Arial, Helvetica, sans-serif;font-size:10.02pt;"&gt;$0&lt;/span&gt;&lt;/div&gt;
            &lt;/td&gt;
         &lt;/tr&gt;
      &lt;/table&gt;&lt;/div&gt;</oef:AddlFundStatisticsTextBlock>
    <us-gaap:AssetsNet
      contextRef="c_8464_instant_LiquidReservesPortfolio_SingleClass_2026-08-31Member"
      decimals="INF"
      id="ixv-5142"
      unitRef="USD">7929064637</us-gaap:AssetsNet>
    <oef:HoldingsCount
      contextRef="c_8464_instant_LiquidReservesPortfolio_SingleClass_2026-08-31Member"
      decimals="INF"
      id="ixv-5143"
      unitRef="UNIT">68</oef:HoldingsCount>
    <oef:AdvisoryFeesPaidAmt
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      decimals="INF"
      id="ixv-5144"
      unitRef="USD">0</oef:AdvisoryFeesPaidAmt>
    <oef:HoldingsTableTextBlock
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      id="foot-8464_912693-1011"
      xml:lang="en-US">&lt;div&gt;&lt;span style="text-transform:uppercase;"&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:12.024pt;text-transform:uppercase;color:#1447FF;;"&gt;&lt;b&gt;WHAT DID THE FUND INVEST IN? &lt;/b&gt;&lt;/span&gt;&lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.824pt;color:#2D2D2D;;"&gt;(as of &lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:10.824pt;color:#2D2D2D;;"&gt;August 31, 2026)&lt;/span&gt;&lt;/div&gt;&lt;div&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:12.024pt;color:#161616;;"&gt;&lt;b&gt;Portfolio Composition &lt;/b&gt;&lt;/span&gt;&lt;span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:12.024pt;color:#161616;;"&gt;&lt;b&gt;(% of Total Investments)&lt;/b&gt;&lt;/span&gt;&lt;/div&gt;&lt;div&gt;&lt;img alt="image" src="ts8464img004.jpg" style="width:96.41294838145232%"/&gt;&lt;/div&gt;</oef:HoldingsTableTextBlock>
    <oef:UpdProspectusWebAddress
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      id="ixv-264"
      xml:lang="en-US">https://www.franklintempleton.com/regulatory-masterfunds-documents</oef:UpdProspectusWebAddress>
    <dei:NoTradingSymbolFlag
      contextRef="c_8464_duration_LiquidReservesPortfolio_SingleClass_2025-09-01_2026-08-31Member"
      id="ixv-5145">true</dei:NoTradingSymbolFlag>
    <oef:PctOfTotalInv
      contextRef="c_8464_instant_LiquidReservesPortfolio_SingleClass_2026-08-31_4123Member"
      decimals="INF"
      id="ixv-5146"
      unitRef="RATIO">0.433</oef:PctOfTotalInv>
    <oef:PctOfTotalInv
      contextRef="c_8464_instant_LiquidReservesPortfolio_SingleClass_2026-08-31_4120Member"
      decimals="INF"
      id="ixv-5147"
      unitRef="RATIO">0.323</oef:PctOfTotalInv>
    <oef:PctOfTotalInv
      contextRef="c_8464_instant_LiquidReservesPortfolio_SingleClass_2026-08-31_4125Member"
      decimals="INF"
      id="ixv-5148"
      unitRef="RATIO">0.164</oef:PctOfTotalInv>
    <oef:PctOfTotalInv
      contextRef="c_8464_instant_LiquidReservesPortfolio_SingleClass_2026-08-31_4122Member"
      decimals="INF"
      id="ixv-5149"
      unitRef="RATIO">0.067</oef:PctOfTotalInv>
    <oef:PctOfTotalInv
      contextRef="c_8464_instant_LiquidReservesPortfolio_SingleClass_2026-08-31_4121Member"
      decimals="INF"
      id="ixv-5150"
      unitRef="RATIO">0.013</oef:PctOfTotalInv>
    <link:footnoteLink
      xlink:role="http://www.xbrl.org/2003/role/link"
      xlink:type="extended">
        <link:loc
          xlink:href="#foot-8464_912687-1011"
          xlink:label="foot-8464_912687-1011"
          xlink:type="locator"/>
        <link:footnote id="WSF_8464_912687_91364" xlink:label="WSF_8464_912687_91364" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en"><xhtml:table style="padding-top:5pt;width:100%;cellspacing:0;margin-left:8pt;"><xhtml:tr><xhtml:td style="vertical-align:top;font-family:Arial, Helvetica, sans-serif;font-size:6pt;text-align:left;align:left;width:2%;"><xhtml:span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:8.02pt;color:#6B6B6B;;">*</xhtml:span></xhtml:td><xhtml:td style="padding-bottom:0pt;padding-top:-10.02pt;padding-left:2pt;padding-right:0pt;"><xhtml:span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:9.02pt;color:#6B6B6B;;">Reflects fee waivers and/or expense reimbursements, without which expenses would have been higher. Additional amounts may be voluntarily </xhtml:span><xhtml:span style="clear:both;font-family:Arial, Helvetica, sans-serif;font-size:9.02pt;color:#6B6B6B;;">waived and/or reimbursed from time to time.</xhtml:span></xhtml:td></xhtml:tr></xhtml:table></link:footnote>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="foot-8464_912687-1011"
          xlink:to="WSF_8464_912687_91364"
          xlink:type="arc"/>
    </link:footnoteLink>
</xbrl>
