<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.22.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>7</ContextCount>
  <ElementCount>20</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>5</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>2</UnitCount>
  <MyReports>
    <Report instance="filing960.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000000 - Document - Document and Entity Information {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.proofPlus.com/role/DocumentInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory></MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="filing960.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>000001 - Document - Risk/Return Summary {Unlabeled} - Fidelity?? Tax-Exempt Money Market Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.proofPlus.com/role/SummaryS000007504_D1031FidelityTaxExemptMoneyMarketFundTreasuryMoneyMarketFundRetailComboPRO16</Role>
      <ShortName>Risk/Return Summary- Fidelity?? Tax-Exempt Money Market Fund</ShortName>
      <MenuCategory></MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="filing960.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>000003 - Schedule - Annual Operating Expenses {- Fidelity?? Tax-Exempt Money Market Fund}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.proofPlus.com/role/OperatingExpensesS000007504_D1031FidelityTaxExemptMoneyMarketFundTreasuryMoneyMarketFundRetailComboPRO16</Role>
      <ShortName>Annual Operating Expenses {- Fidelity?? Tax-Exempt Money Market Fund}</ShortName>
      <MenuCategory></MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="filing960.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>000004 - Schedule - Expense Example {- Fidelity?? Tax-Exempt Money Market Fund}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.proofPlus.com/role/ExpenseExampleS000007504_D1031FidelityTaxExemptMoneyMarketFundTreasuryMoneyMarketFundRetailComboPRO16</Role>
      <ShortName>Expense Example {- Fidelity?? Tax-Exempt Money Market Fund}</ShortName>
      <MenuCategory></MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="filing960.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>000009 - Disclosure - Risk/Return Detail Data {Elements} - Fidelity?? Tax-Exempt Money Market Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.proofPlus.com/role/DisclosureDetailS000007504_D1031FidelityTaxExemptMoneyMarketFundTreasuryMoneyMarketFundRetailComboPRO16</Role>
      <ShortName>Risk/Return Detail Data- Fidelity?? Tax-Exempt Money Market Fund</ShortName>
      <MenuCategory></MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="filing960.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>000010 - Document - Risk/Return Summary {Unlabeled} - Fidelity?? Tax-Exempt Money Market Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.proofPlus.com/role/SummaryS000007504_D1031FidelityTaxExemptMoneyMarketFundPremiumPRO11</Role>
      <ShortName>Risk/Return Summary- Fidelity?? Tax-Exempt Money Market Fund</ShortName>
      <MenuCategory></MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="filing960.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>000012 - Schedule - Annual Operating Expenses {- Fidelity?? Tax-Exempt Money Market Fund}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.proofPlus.com/role/OperatingExpensesS000007504_D1031FidelityTaxExemptMoneyMarketFundPremiumPRO11</Role>
      <ShortName>Annual Operating Expenses {- Fidelity?? Tax-Exempt Money Market Fund}</ShortName>
      <MenuCategory></MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="filing960.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>000013 - Schedule - Expense Example {- Fidelity?? Tax-Exempt Money Market Fund}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.proofPlus.com/role/ExpenseExampleS000007504_D1031FidelityTaxExemptMoneyMarketFundPremiumPRO11</Role>
      <ShortName>Expense Example {- Fidelity?? Tax-Exempt Money Market Fund}</ShortName>
      <MenuCategory></MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="filing960.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>000018 - Disclosure - Risk/Return Detail Data {Elements} - Fidelity?? Tax-Exempt Money Market Fund</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.proofPlus.com/role/DisclosureDetailS000007504_D1031FidelityTaxExemptMoneyMarketFundPremiumPRO11</Role>
      <ShortName>Risk/Return Detail Data- Fidelity?? Tax-Exempt Money Market Fund</ShortName>
      <MenuCategory></MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="filing960.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>040000 - Disclosure - Risk/Return Detail Data {Elements}</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/rr/role/RiskReturnDetailData</Role>
      <ShortName>Risk/Return Detail Data</ShortName>
      <MenuCategory></MenuCategory>
      <Position>10</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="497" original="filing960.htm">filing960.htm</File>
    <File>tp1-20220712.xsd</File>
    <File>tp1-20220712_cal.xml</File>
    <File>tp1-20220712_def.xml</File>
    <File>tp1-20220712_lab.xml</File>
    <File>tp1-20220712_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="6">http://xbrl.sec.gov/dei/2021</BaseTaxonomy>
    <BaseTaxonomy items="28">http://xbrl.sec.gov/rr/2021</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
