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    <unit id="usd">
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        <measure>pure</measure>
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    <dei:AmendmentFlag contextRef="Trust" id="ixv-40917">false</dei:AmendmentFlag>
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    <dei:EntityRegistrantName contextRef="Trust" id="ixv-40920">Fidelity Concord Street Trust</dei:EntityRegistrantName>
    <oef:RiskReturnHeading contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-209">


     Fund Summary

     Fund:
     Fidelity&#xae; Series Total Market Index Fund

   </oef:RiskReturnHeading>
    <oef:ObjectiveHeading contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-218">


     Investment Objective


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     Fidelity&#xae; Series Total Market Index Fund seeks to provide investment results that correspond to the total return of a broad range of U.S. stocks.


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     Fee Table


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     The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund.

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     Shareholder fees


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      contextRef="Pid_S000065248_contentCd_STX-PRO"
      decimals="0"
      id="ixv-43055"
      unitRef="usd">0</oef:ShareholderFeeOther>
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     Annual Operating Expenses


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    <oef:ManagementFeesOverAssets
      contextRef="Pid_S000065248_Cid_C000211233"
      decimals="6"
      id="ixv-43056"
      unitRef="pure">0.0000</oef:ManagementFeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Pid_S000065248_Cid_C000211233"
      decimals="6"
      id="ixv-43057"
      unitRef="pure">0</oef:DistributionAndService12b1FeesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Pid_S000065248_Cid_C000211233"
      decimals="6"
      id="ixv-43058"
      unitRef="pure">0.0000</oef:OtherExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Pid_S000065248_Cid_C000211233"
      decimals="6"
      id="ixv-43059"
      unitRef="pure">0.0000</oef:ExpensesOverAssets>
    <oef:ExpenseExampleNarrativeTextBlock contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-306">


     This
     example

     helps compare the cost of investing in the fund with the cost of investing in other funds.

     Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

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      contextRef="Pid_S000065248_Cid_C000211233"
      decimals="0"
      id="ixv-43060"
      unitRef="usd">0</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Pid_S000065248_Cid_C000211233"
      decimals="0"
      id="ixv-43061"
      unitRef="usd">0</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleYear05
      contextRef="Pid_S000065248_Cid_C000211233"
      decimals="0"
      id="ixv-43062"
      unitRef="usd">0</oef:ExpenseExampleYear05>
    <oef:ExpenseExampleYear10
      contextRef="Pid_S000065248_Cid_C000211233"
      decimals="0"
      id="ixv-43063"
      unitRef="usd">0</oef:ExpenseExampleYear10>
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     Portfolio Turnover


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     The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was



       11


     % of the average value of its portfolio.


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    <oef:PortfolioTurnoverRate
      contextRef="Pid_S000065248_contentCd_STX-PRO"
      decimals="4"
      id="ixv-43064"
      unitRef="pure">0.11</oef:PortfolioTurnoverRate>
    <oef:StrategyHeading contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-377">


     Principal Investment Strategies


   </oef:StrategyHeading>
    <oef:StrategyNarrativeTextBlock contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-382">




        Normally investing at least 80% of assets in equity securities included in the Dow Jones U.S. Total Stock Market IndexSM.

     The Dow Jones U.S. Total Stock Market Index SM is a float-adjusted market capitalization-weighted index of approximately 5,000 common stocks of companies headquartered in the United States
        and listed on a primary U.S. exchange. The index represents the performance of a broad range of U.S.
       stocks.


        Derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.
      Using statistical sampling techniques based on such factors as capitalization, industry exposures, dividend yield, price-to-earnings (P/E) ratio, price-to-book (P/B) ratio, and earnings growth to attempt to replicate the returns of the Dow Jones U.S. Total Stock Market Index&#x2120;.
      Lending securities to earn income for the fund.

     The fund may operate as a non-diversified fund, as defined under the Investment Company Act of 1940 (1940 Act), to the approximate extent the index is non-diversified. The fund may therefore operate as non-diversified solely as a result of a change in relative market capitalization or index weighting of one or more constituents of the index.

   </oef:StrategyNarrativeTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000065248_contentCd_STX-PRO_RiskMember_StockMarketVolatilityMember"
      id="ixv-416">



      Stock Market Volatility.

     Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market, including different market sectors, and different types of securities can react differently to these developments.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000065248_contentCd_STX-PRO_RiskMember_IssuerSpecificChangesMember"
      id="ixv-425">



      Issuer-Specific Changes.

     The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole.
     Changes in the financial condition of an issuer or counterparty (e.g., broker-dealer or other borrower in a securities lending transaction) can increase the risk of default by an issuer or counterparty, which can affect a security's or instrument's value or result in delays in recovering securities and/or capital from a counterparty.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000065248_contentCd_STX-PRO_RiskMember_CorrelationToIndexMember"
      id="ixv-436">



      Correlation to Index.

     The performance of the fund and its underlying index may vary somewhat due to factors such as fees and expenses of the fund, transaction costs, sample selection, regulatory restrictions, and timing differences associated with additions to and deletions from the index. Errors in the construction or calculation of the index may occur from time to time and may not be identified and corrected for some period of time, which may have an adverse impact on the fund and its shareholders.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000065248_contentCd_STX-PRO_RiskMember_PassiveManagementRiskMember"
      id="ixv-445">



      Passive Management Risk.

     The fund is managed with a passive investment strategy, attempting to track the performance of an unmanaged index of securities, regardless of the current or projected performance of the fund's index or of the actual securities included in the index. This differs from an actively managed fund, which typically seeks to outperform a benchmark index. As a result, the fund's performance could be lower than actively managed funds that may shift their portfolio assets to take advantage of market opportunities or lessen the impact of a market decline or a decline in the value of one or more issuers.
     The fund will be concentrated to approximately the same extent that the fund's index concentrates in the securities of issuers in a particular industry.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000065248_contentCd_STX-PRO_RiskMember_SecuritiesLendingRiskMember"
      id="ixv-456">



      Securities Lending Risk.

     Securities lending involves the risk that the borrower may fail to return the securities loaned in a timely manner or at all. If the borrower defaults on its obligation to return the securities loaned because of insolvency or other reasons, a fund could experience delays and costs in recovering the securities loaned or in gaining access to the collateral.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000065248_contentCd_STX-PRO_RiskMember_RiskNondiversifiedStatusMember"
      id="ixv-465">


     In addition, the fund may operate as a non-diversified fund under the 1940 Act to the approximate extent the index is non-diversified. A non-diversified fund may invest a greater portion of its assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.


   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000065248_contentCd_STX-PRO_RiskMember_RiskNotInsuredDepositoryInstitutionMember"
      id="ixv-470">


     An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency

     .


   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000065248_contentCd_STX-PRO_RiskMember_RiskLoseMoneyMember"
      id="ixv-478">


     &#160;

     You could lose money by investing in the fund.


   </oef:RiskTextBlock>
    <oef:BarChartAndPerformanceTableHeading contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-485">


     Performance


   </oef:BarChartAndPerformanceTableHeading>
    <oef:PerformanceNarrativeTextBlock contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-490">


     The following information is intended to help you understand the risks of investing in the fund.


      The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.



     The index description appears in the "Additional Index Information" section of the prospectus.



      Past performance (before and after taxes) is not an indication of future performance.


     The performance shown does not reflect the impact of any fees paid at the fee-based account or plan level, if applicable.
     Visit



      www.fidelity.com


     for more recent performance information.

   </oef:PerformanceNarrativeTextBlock>
    <oef:PerformanceInformationIllustratesVariabilityOfReturns contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-495">

      The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.

     </oef:PerformanceInformationIllustratesVariabilityOfReturns>
    <oef:PerformancePastDoesNotIndicateFuture contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-502">

      Past performance (before and after taxes) is not an indication of future performance.

     </oef:PerformancePastDoesNotIndicateFuture>
    <oef:PerformanceAvailabilityWebSiteAddress contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-510">

      www.fidelity.com
     </oef:PerformanceAvailabilityWebSiteAddress>
    <oef:BarChartHeading contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-515">


     Year-by-Year Returns

   </oef:BarChartHeading>
    <oef:AnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_2020"
      decimals="INF"
      id="ixv-43065"
      unitRef="pure">0.2079</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_2021"
      decimals="INF"
      id="ixv-43066"
      unitRef="pure">0.2563</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_2022"
      decimals="INF"
      id="ixv-43067"
      unitRef="pure">-0.1953</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_2023"
      decimals="INF"
      id="ixv-43068"
      unitRef="pure">0.2614</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_2024"
      decimals="INF"
      id="ixv-43069"
      unitRef="pure">0.2391</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_2025"
      decimals="INF"
      id="ixv-43070"
      unitRef="pure">0.1705</oef:AnnlRtrPct>
    <oef:HighestQuarterlyReturnLabel contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-613">
          &#160;&#160;&#160;Highest Quarter Return
        </oef:HighestQuarterlyReturnLabel>
    <oef:BarChartHighestQuarterlyReturn
      contextRef="Pid_S000065248_contentCd_STX-PRO"
      decimals="4"
      id="ixv-43071"
      unitRef="pure">0.2208</oef:BarChartHighestQuarterlyReturn>
    <oef:BarChartHighestQuarterlyReturnDate contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-623">2020-06-30</oef:BarChartHighestQuarterlyReturnDate>
    <oef:LowestQuarterlyReturnLabel contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-628">
          &#160;&#160;&#160;Lowest Quarter Return
        </oef:LowestQuarterlyReturnLabel>
    <oef:BarChartLowestQuarterlyReturn
      contextRef="Pid_S000065248_contentCd_STX-PRO"
      decimals="4"
      id="ixv-43072"
      unitRef="pure">-0.2099</oef:BarChartLowestQuarterlyReturn>
    <oef:BarChartLowestQuarterlyReturnDate contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-639">2020-03-31</oef:BarChartLowestQuarterlyReturnDate>
    <oef:YearToDateReturnLabel contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-644">
          &#160;&#160;&#160;Year-to-Date Return
        </oef:YearToDateReturnLabel>
    <oef:BarChartYearToDateReturn
      contextRef="Pid_S000065248_contentCd_STX-PRO"
      decimals="4"
      id="ixv-43073"
      unitRef="pure">-0.0401</oef:BarChartYearToDateReturn>
    <oef:BarChartYearToDateReturnDate contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-655">2026-03-31</oef:BarChartYearToDateReturnDate>
    <oef:PerformanceTableHeading contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-660">


     Average Annual Returns


   </oef:PerformanceTableHeading>
    <oef:PerformanceTableNarrativeTextBlock contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-665">




      After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.



     Actual after-tax returns may differ depending on your individual circumstances.



      The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).





      Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.




   </oef:PerformanceTableNarrativeTextBlock>
    <oef:PerformanceTableUsesHighestFederalRate contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-668">

      After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.

     </oef:PerformanceTableUsesHighestFederalRate>
    <oef:PerformanceTableNotRelevantToTaxDeferred contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-675">

      The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).

     </oef:PerformanceTableNotRelevantToTaxDeferred>
    <oef:PerformanceTableExplanationAfterTaxHigher contextRef="Pid_S000065248_contentCd_STX-PRO" id="ixv-680">

      Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.

     </oef:PerformanceTableExplanationAfterTaxHigher>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000065248_Cid_C000211233_ReturnBeforeTaxes_01"
      id="ixv-726">
         Return Before Taxes
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_ReturnBeforeTaxes_01"
      decimals="4"
      id="ixv-43074"
      unitRef="pure">0.1705</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_ReturnBeforeTaxes_05"
      decimals="4"
      id="ixv-43075"
      unitRef="pure">0.1309</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_ReturnBeforeTaxes_AverageAnnualReturnSinceInception"
      decimals="4"
      id="footnoteSTX-PROS000065248AAR_A_RBT_loc"
      unitRef="pure">0.1449</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000065248_Cid_C000211233_AfterTaxesOnDistributions_01"
      id="ixv-742">
         Return After Taxes on Distributions
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_AfterTaxesOnDistributions_01"
      decimals="4"
      id="ixv-43077"
      unitRef="pure">0.1669</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_AfterTaxesOnDistributions_05"
      decimals="4"
      id="ixv-43078"
      unitRef="pure">0.1267</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_AfterTaxesOnDistributions_AverageAnnualReturnSinceInception"
      decimals="4"
      id="footnoteSTX-PROS000065248AAR_A_ATD_loc"
      unitRef="pure">0.1401</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000065248_Cid_C000211233_AfterTaxesOnDistributionsAndSales_01"
      id="ixv-758">
         Return After Taxes on Distributions and Sale of Fund Shares
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_AfterTaxesOnDistributionsAndSales_01"
      decimals="4"
      id="ixv-43080"
      unitRef="pure">0.1029</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_AfterTaxesOnDistributionsAndSales_05"
      decimals="4"
      id="ixv-43081"
      unitRef="pure">0.1038</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000065248_Cid_C000211233_AfterTaxesOnDistributionsAndSales_AverageAnnualReturnSinceInception"
      decimals="4"
      id="footnoteSTX-PROS000065248AAR_A_ATDS_loc"
      unitRef="pure">0.1172</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000065248_Indexid_WA006_contentCd_STX-PRO_01"
      id="ixv-775">
         Dow Jones U.S. Total Stock Market Index&#x2120;
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000065248_Indexid_WA006_contentCd_STX-PRO_01"
      decimals="4"
      id="ixv-43083"
      unitRef="pure">0.1705</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000065248_Indexid_WA006_contentCd_STX-PRO_05"
      decimals="4"
      id="ixv-43084"
      unitRef="pure">0.1307</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000065248_Indexid_WA006_contentCd_STX-PRO_AverageAnnualReturnSinceInception"
      decimals="4"
      id="ixv-43085"
      unitRef="pure">0.1447</oef:AvgAnnlRtrPct>
    <oef:AnnualReturnInceptionDate contextRef="Pid_S000065248_Cid_C000211233" id="ixv-816">2019-04-26</oef:AnnualReturnInceptionDate>
    <oef:RiskReturnHeading contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2411">


     Fund Summary

     Fund:
     Fidelity Flex&#xae; 500 Index Fund


   </oef:RiskReturnHeading>
    <oef:ObjectiveHeading contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2422">


     Investment Objective


   </oef:ObjectiveHeading>
    <oef:ObjectivePrimaryTextBlock contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2427">


     Fidelity Flex&#xae; 500 Index Fund seeks to provide investment results that correspond to the total return of stocks of large capitalization U.S. companies.


   </oef:ObjectivePrimaryTextBlock>
    <oef:ExpenseHeading contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2432">


     Fee Table


   </oef:ExpenseHeading>
    <oef:ExpenseNarrativeTextBlock contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2438">


     The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions, which are not reflected in the tables and examples below.

   </oef:ExpenseNarrativeTextBlock>
    <oef:ShareholderFeesCaption contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2450">


     Shareholder fees


   </oef:ShareholderFeesCaption>
    <oef:ShareholderFeeOther
      contextRef="Pid_S000056363_contentCd_Z5I-PRO"
      decimals="0"
      id="ixv-43086"
      unitRef="usd">0</oef:ShareholderFeeOther>
    <oef:OperatingExpensesCaption contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2466">


     Annual Operating Expenses


   </oef:OperatingExpensesCaption>
    <oef:ManagementFeesOverAssets
      contextRef="Pid_S000056363_Cid_C000177590"
      decimals="6"
      id="ixv-43087"
      unitRef="pure">0.0000</oef:ManagementFeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Pid_S000056363_Cid_C000177590"
      decimals="6"
      id="ixv-43088"
      unitRef="pure">0</oef:DistributionAndService12b1FeesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Pid_S000056363_Cid_C000177590"
      decimals="6"
      id="ixv-43089"
      unitRef="pure">0.0000</oef:OtherExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Pid_S000056363_Cid_C000177590"
      decimals="6"
      id="footnoteS000056363Z5I-PROAOE_AC000177590_TE"
      unitRef="pure">0.0000</oef:ExpensesOverAssets>
    <oef:ExpenseExampleNarrativeTextBlock contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2521">


     This
     example

     helps compare the cost of investing in the fund with the cost of investing in other funds.

     Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. This example does not include any fees paid at the fee-based account or plan level. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

   </oef:ExpenseExampleNarrativeTextBlock>
    <oef:ExpenseExampleYear01
      contextRef="Pid_S000056363_Cid_C000177590"
      decimals="0"
      id="ixv-43091"
      unitRef="usd">0</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Pid_S000056363_Cid_C000177590"
      decimals="0"
      id="ixv-43092"
      unitRef="usd">0</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleYear05
      contextRef="Pid_S000056363_Cid_C000177590"
      decimals="0"
      id="ixv-43093"
      unitRef="usd">0</oef:ExpenseExampleYear05>
    <oef:ExpenseExampleYear10
      contextRef="Pid_S000056363_Cid_C000177590"
      decimals="0"
      id="ixv-43094"
      unitRef="usd">0</oef:ExpenseExampleYear10>
    <oef:PortfolioTurnoverHeading contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2578">


     Portfolio Turnover


   </oef:PortfolioTurnoverHeading>
    <oef:PortfolioTurnoverTextBlock contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2583">


     The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was





       4


     % of the average value of its portfolio.


   </oef:PortfolioTurnoverTextBlock>
    <oef:PortfolioTurnoverRate
      contextRef="Pid_S000056363_contentCd_Z5I-PRO"
      decimals="4"
      id="ixv-43095"
      unitRef="pure">0.04</oef:PortfolioTurnoverRate>
    <oef:StrategyHeading contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2593">


     Principal Investment Strategies


   </oef:StrategyHeading>
    <oef:StrategyNarrativeTextBlock contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2598">



      Normally investing at least 80% of assets in securities included in the Fidelity U.S. Large Cap IndexSM.

     The Fidelity U.S. Large Cap Index SM is a float-adjusted market capitalization-weighted index designed to reflect the performance of U.S. large capitalization stocks. It is a subset of the Fidelity U.S. Total Investable Market Index SM (a float-adjusted market capitalization-weighted index designed to reflect the performance of the U.S. equity market, including large-, mid-, and small-capitalization stocks) representing the largest companies. Large capitalization stocks are considered to be stocks of the largest 500 U.S. companies based on float-adjusted market capitalization.
     The Fidelity U.S. Large Cap Index SM was created by Fidelity Product Services LLC (FPS) using a rules-based proprietary index methodology that includes all U.S. stocks meeting certain market capitalization, liquidity, and investability requirements.
     Derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.

      Lending securities to earn income for the fund.


   </oef:StrategyNarrativeTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000056363_contentCd_Z5I-PRO_RiskMember_StockMarketVolatilityMember"
      id="ixv-2629">



      Stock Market Volatility.

     Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market, including different market sectors, and different types of securities can react differently to these developments.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000056363_contentCd_Z5I-PRO_RiskMember_IssuerSpecificChangesMember"
      id="ixv-2638">



      Issuer-Specific Changes.

     The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole.
     Changes in the financial condition of an issuer or counterparty (e.g., broker-dealer or other borrower in a securities lending transaction) can increase the risk of default by an issuer or counterparty, which can affect a security's or instrument's value or result in delays in recovering securities and/or capital from a counterparty.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000056363_contentCd_Z5I-PRO_RiskMember_CorrelationToIndexMember"
      id="ixv-2649">



      Correlation to Index.

     The performance of the fund and its underlying index may vary somewhat due to factors such as fees and expenses of the fund, transaction costs, sample selection, regulatory restrictions, and timing differences associated with additions to and deletions from the index. Errors in the construction or calculation of the index may occur from time to time and may not be identified and corrected for some period of time, which may have an adverse impact on the fund and its shareholders.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000056363_contentCd_Z5I-PRO_RiskMember_PassiveManagementRiskMember"
      id="ixv-2658">



      Passive Management Risk.

     The fund is managed with a passive investment strategy, attempting to track the performance of an unmanaged index of securities, regardless of the current or projected performance of the fund's index or of the actual securities included in the index. This differs from an actively managed fund, which typically seeks to outperform a benchmark index. As a result, the fund's performance could be lower than actively managed funds that may shift their portfolio assets to take advantage of market opportunities or lessen the impact of a market decline or a decline in the value of one or more issuers.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000056363_contentCd_Z5I-PRO_RiskMember_RulesBasedStrategyRiskMember"
      id="ixv-2667">



      Rules-Based Strategy Risk.

     Although the index uses a rules-based proprietary index methodology, there is no guarantee that this methodology will be successful.&#160;

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000056363_contentCd_Z5I-PRO_RiskMember_SecuritiesLendingRiskMember"
      id="ixv-2677">



      Securities Lending Risk.

     Securities lending involves the risk that the borrower may fail to return the securities loaned in a timely manner or at all. If the borrower defaults on its obligation to return the securities loaned because of insolvency or other reasons, a fund could experience delays and costs in recovering the securities loaned or in gaining access to the collateral.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000056363_contentCd_Z5I-PRO_RiskMember_RiskNotInsuredDepositoryInstitutionMember"
      id="ixv-2686">


     An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency

     .


   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000056363_contentCd_Z5I-PRO_RiskMember_RiskLoseMoneyMember"
      id="ixv-2694">


     &#160;

     You could lose money by investing in the fund.


   </oef:RiskTextBlock>
    <oef:BarChartAndPerformanceTableHeading contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2701">


     Performance


   </oef:BarChartAndPerformanceTableHeading>
    <oef:PerformanceNarrativeTextBlock contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2706">


     The following information is intended to help you understand the risks of investing in the fund.


      The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and additional indexes over various periods of time.



     The additional indexes have characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus.



      Past performance (before and after taxes) is not an indication of future performance.


     The performance shown does not reflect the impact of any fees paid at the fee-based account or plan level.
     Prior to July 21, 2025, the fund compared its performance to a different benchmark. The fund's historical performance may not represent its current investment policies.
     Visit



      www.401k.com and log in or www.fidelity.com


     for more recent performance information.

   </oef:PerformanceNarrativeTextBlock>
    <oef:PerformanceInformationIllustratesVariabilityOfReturns contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2711">

      The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and additional indexes over various periods of time.

     </oef:PerformanceInformationIllustratesVariabilityOfReturns>
    <oef:PerformancePastDoesNotIndicateFuture contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2718">

      Past performance (before and after taxes) is not an indication of future performance.

     </oef:PerformancePastDoesNotIndicateFuture>
    <oef:PerformanceAvailabilityWebSiteAddress contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2728">

      www.401k.com and log in or www.fidelity.com
     </oef:PerformanceAvailabilityWebSiteAddress>
    <oef:BarChartHeading contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2733">


     Year-by-Year Returns

   </oef:BarChartHeading>
    <oef:AnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_2018"
      decimals="INF"
      id="ixv-43096"
      unitRef="pure">-0.0443</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_2019"
      decimals="INF"
      id="ixv-43097"
      unitRef="pure">0.3146</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_2020"
      decimals="INF"
      id="ixv-43098"
      unitRef="pure">0.1844</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_2021"
      decimals="INF"
      id="ixv-43099"
      unitRef="pure">0.2869</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_2022"
      decimals="INF"
      id="ixv-43100"
      unitRef="pure">-0.1809</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_2023"
      decimals="INF"
      id="ixv-43101"
      unitRef="pure">0.2627</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_2024"
      decimals="INF"
      id="ixv-43102"
      unitRef="pure">0.2504</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_2025"
      decimals="INF"
      id="ixv-43103"
      unitRef="pure">0.1761</oef:AnnlRtrPct>
    <oef:HighestQuarterlyReturnLabel contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2838">
          &#160;&#160;&#160;Highest Quarter Return
        </oef:HighestQuarterlyReturnLabel>
    <oef:BarChartHighestQuarterlyReturn
      contextRef="Pid_S000056363_contentCd_Z5I-PRO"
      decimals="4"
      id="ixv-43104"
      unitRef="pure">0.2052</oef:BarChartHighestQuarterlyReturn>
    <oef:BarChartHighestQuarterlyReturnDate contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2848">2020-06-30</oef:BarChartHighestQuarterlyReturnDate>
    <oef:LowestQuarterlyReturnLabel contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2853">
          &#160;&#160;&#160;Lowest Quarter Return
        </oef:LowestQuarterlyReturnLabel>
    <oef:BarChartLowestQuarterlyReturn
      contextRef="Pid_S000056363_contentCd_Z5I-PRO"
      decimals="4"
      id="ixv-43105"
      unitRef="pure">-0.1956</oef:BarChartLowestQuarterlyReturn>
    <oef:BarChartLowestQuarterlyReturnDate contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2864">2020-03-31</oef:BarChartLowestQuarterlyReturnDate>
    <oef:YearToDateReturnLabel contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2869">
          &#160;&#160;&#160;Year-to-Date Return
        </oef:YearToDateReturnLabel>
    <oef:BarChartYearToDateReturn
      contextRef="Pid_S000056363_contentCd_Z5I-PRO"
      decimals="4"
      id="ixv-43106"
      unitRef="pure">-0.0460</oef:BarChartYearToDateReturn>
    <oef:BarChartYearToDateReturnDate contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2880">2026-03-31</oef:BarChartYearToDateReturnDate>
    <oef:PerformanceTableHeading contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2886">


     Average Annual Returns


   </oef:PerformanceTableHeading>
    <oef:PerformanceTableNarrativeTextBlock contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2891">




      After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.



     Actual after-tax returns may differ depending on your individual circumstances.



      The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).





      Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.






   </oef:PerformanceTableNarrativeTextBlock>
    <oef:PerformanceTableUsesHighestFederalRate contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2894">

      After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.

     </oef:PerformanceTableUsesHighestFederalRate>
    <oef:PerformanceTableNotRelevantToTaxDeferred contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2901">

      The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).

     </oef:PerformanceTableNotRelevantToTaxDeferred>
    <oef:PerformanceTableExplanationAfterTaxHigher contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-2906">

      Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.



     </oef:PerformanceTableExplanationAfterTaxHigher>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000056363_Cid_C000177590_ReturnBeforeTaxes_01"
      id="ixv-2953">
         Return Before Taxes
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_ReturnBeforeTaxes_01"
      decimals="4"
      id="ixv-43107"
      unitRef="pure">0.1761</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_ReturnBeforeTaxes_05"
      decimals="4"
      id="ixv-43108"
      unitRef="pure">0.1438</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_ReturnBeforeTaxes_AverageAnnualReturnSinceInception"
      decimals="4"
      id="footnoteZ5I-PROS000056363AAR_A_RBT_loc"
      unitRef="pure">0.1468</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000056363_Cid_C000177590_AfterTaxesOnDistributions_01"
      id="ixv-2969">
         Return After Taxes on Distributions
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_AfterTaxesOnDistributions_01"
      decimals="4"
      id="ixv-43110"
      unitRef="pure">0.1726</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_AfterTaxesOnDistributions_05"
      decimals="4"
      id="ixv-43111"
      unitRef="pure">0.1397</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_AfterTaxesOnDistributions_AverageAnnualReturnSinceInception"
      decimals="4"
      id="footnoteZ5I-PROS000056363AAR_A_ATD_loc"
      unitRef="pure">0.1423</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000056363_Cid_C000177590_AfterTaxesOnDistributionsAndSales_01"
      id="ixv-2985">
         Return After Taxes on Distributions and Sale of Fund Shares
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_AfterTaxesOnDistributionsAndSales_01"
      decimals="4"
      id="ixv-43113"
      unitRef="pure">0.1062</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_AfterTaxesOnDistributionsAndSales_05"
      decimals="4"
      id="ixv-43114"
      unitRef="pure">0.1146</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Cid_C000177590_AfterTaxesOnDistributionsAndSales_AverageAnnualReturnSinceInception"
      decimals="4"
      id="footnoteZ5I-PROS000056363AAR_A_ATDS_loc"
      unitRef="pure">0.1213</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000056363_Indexid_IXRP2_contentCd_Z5I-PRO_01"
      id="ixv-3002">
         Fidelity Flex 500 Linked Index&#x2120;
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Indexid_IXRP2_contentCd_Z5I-PRO_01"
      decimals="4"
      id="ixv-43116"
      unitRef="pure">0.1762</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Indexid_IXRP2_contentCd_Z5I-PRO_05"
      decimals="4"
      id="ixv-43117"
      unitRef="pure">0.1437</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Indexid_IXRP2_contentCd_Z5I-PRO_AverageAnnualReturnSinceInception"
      decimals="4"
      id="ixv-43118"
      unitRef="pure">0.1468</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000056363_Indexid_IXYDD_contentCd_Z5I-PRO_01"
      id="ixv-3027">
         Fidelity U.S. Large Cap Index&#x2120;
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Indexid_IXYDD_contentCd_Z5I-PRO_01"
      decimals="4"
      id="ixv-43119"
      unitRef="pure">0.1781</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Indexid_IXYDD_contentCd_Z5I-PRO_05"
      decimals="4"
      id="ixv-43120"
      unitRef="pure">0.1399</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Indexid_IXYDD_contentCd_Z5I-PRO_AverageAnnualReturnSinceInception"
      id="footnoteZ5I-PROS000056363AAR_B_BM_1_loc"
      unitRef="pure"
      xsi:nil="true"/>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000056363_Indexid_SP001_contentCd_Z5I-PRO_01"
      id="ixv-3054">
         S&amp;P 500&#xae; Index
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Indexid_SP001_contentCd_Z5I-PRO_01"
      decimals="4"
      id="ixv-43122"
      unitRef="pure">0.1788</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Indexid_SP001_contentCd_Z5I-PRO_05"
      decimals="4"
      id="ixv-43123"
      unitRef="pure">0.1442</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000056363_Indexid_SP001_contentCd_Z5I-PRO_AverageAnnualReturnSinceInception"
      decimals="4"
      id="ixv-43124"
      unitRef="pure">0.1471</oef:AvgAnnlRtrPct>
    <oef:AnnualReturnInceptionDate contextRef="Pid_S000056363_Cid_C000177590" id="ixv-3095">2017-03-09</oef:AnnualReturnInceptionDate>
    <oef:PerformanceTableMarketIndexChanged contextRef="Pid_S000056363_contentCd_Z5I-PRO" id="ixv-3109">


     Effective July 21, 2025, the fund began comparing its performance to the Fidelity U.S. Large Cap Index

     SM

     .

     &#160;


   </oef:PerformanceTableMarketIndexChanged>
    <oef:RiskReturnHeading
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-4970">


     Fund Summary

     Fund:
     Fidelity&#xae; Extended Market Index Fund

   </oef:RiskReturnHeading>
    <oef:ObjectiveHeading
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-4979">


     Investment Objective


   </oef:ObjectiveHeading>
    <oef:ObjectivePrimaryTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-4984">


     Fidelity&#xae; Extended Market Index Fund seeks to provide investment results that correspond to the total return of stocks of mid- to small-capitalization United States companies.


   </oef:ObjectivePrimaryTextBlock>
    <oef:ExpenseHeading
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-4989">


     Fee Table


   </oef:ExpenseHeading>
    <oef:ExpenseNarrativeTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-4995">


     The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions, which are not reflected in the tables and examples below.

   </oef:ExpenseNarrativeTextBlock>
    <oef:ShareholderFeesCaption
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5006">


     Shareholder fees


   </oef:ShareholderFeesCaption>
    <oef:ShareholderFeeOther
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      decimals="0"
      id="ixv-43125"
      unitRef="usd">0</oef:ShareholderFeeOther>
    <oef:OperatingExpensesCaption
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5021">


     Annual Operating Expenses


   </oef:OperatingExpensesCaption>
    <oef:ManagementFeesOverAssets
      contextRef="Pid_S000006021_Cid_C000103355"
      decimals="6"
      id="ixv-43126"
      unitRef="pure">0.00035</oef:ManagementFeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Pid_S000006021_Cid_C000103355"
      decimals="6"
      id="ixv-43127"
      unitRef="pure">0</oef:DistributionAndService12b1FeesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Pid_S000006021_Cid_C000103355"
      decimals="6"
      id="ixv-43128"
      unitRef="pure">0.00000</oef:OtherExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Pid_S000006021_Cid_C000103355"
      decimals="6"
      id="ixv-43129"
      unitRef="pure">0.00035</oef:ExpensesOverAssets>
    <oef:ExpenseExampleNarrativeTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5068">


     This
     example

     helps compare the cost of investing in the fund with the cost of investing in other funds.

     Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

   </oef:ExpenseExampleNarrativeTextBlock>
    <oef:ExpenseExampleYear01
      contextRef="Pid_S000006021_Cid_C000103355"
      decimals="0"
      id="ixv-43130"
      unitRef="usd">4</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Pid_S000006021_Cid_C000103355"
      decimals="0"
      id="ixv-43131"
      unitRef="usd">11</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleYear05
      contextRef="Pid_S000006021_Cid_C000103355"
      decimals="0"
      id="ixv-43132"
      unitRef="usd">20</oef:ExpenseExampleYear05>
    <oef:ExpenseExampleYear10
      contextRef="Pid_S000006021_Cid_C000103355"
      decimals="0"
      id="ixv-43133"
      unitRef="usd">45</oef:ExpenseExampleYear10>
    <oef:PortfolioTurnoverHeading
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5125">


     Portfolio Turnover


   </oef:PortfolioTurnoverHeading>
    <oef:PortfolioTurnoverTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5130">


     The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was



       23


     % of the average value of its portfolio.


   </oef:PortfolioTurnoverTextBlock>
    <oef:PortfolioTurnoverRate
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      decimals="4"
      id="ixv-43134"
      unitRef="pure">0.23</oef:PortfolioTurnoverRate>
    <oef:StrategyHeading
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5139">


     Principal Investment Strategies


   </oef:StrategyHeading>
    <oef:StrategyNarrativeTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5144">




        Normally investing at least 80% of assets in common stocks included in the Dow Jones U.S. Completion Total Stock Market IndexSM, which represents the performance of stocks of mid- to small-capitalization U.S. companies.

     The Dow Jones U.S. Completion Total Stock Market Index SM is a float-adjusted market capitalization-weighted index of approximately 4,500 common stocks of companies headquartered in the United States, on a primary U.S. exchange. The Dow Jones U.S. Completion Total Stock Market Index SM broadly represents the performance of stocks of mid- to small-capitalization U.S. companies.

       Derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.

      Using statistical sampling techniques based on such factors as capitalization, industry exposures, dividend yield, price-to-earnings (P/E) ratio, price-to-book (P/B) ratio, and earnings growth to attempt to replicate the returns of the Dow Jones U.S. Completion Total Stock Market Index&#x2120;.
      Lending securities to earn income for the fund.


   </oef:StrategyNarrativeTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO_RiskMember_StockMarketVolatilityMember"
      id="ixv-5174">



      Stock Market Volatility.

     Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market, including different market sectors, and different types of securities can react differently to these developments.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO_RiskMember_IssuerSpecificChangesMember"
      id="ixv-5183">



      Issuer-Specific Changes.

     The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole.
     Changes in the financial condition of an issuer or counterparty (e.g., broker-dealer or other borrower in a securities lending transaction) can increase the risk of default by an issuer or counterparty, which can affect a security's or instrument's value or result in delays in recovering securities and/or capital from a counterparty.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO_RiskMember_CorrelationToIndexMember"
      id="ixv-5194">



      Correlation to Index.

     The performance of the fund and its underlying index may vary somewhat due to factors such as fees and expenses of the fund, transaction costs, sample selection, regulatory restrictions, and timing differences associated with additions to and deletions from the index. Errors in the construction or calculation of the index may occur from time to time and may not be identified and corrected for some period of time, which may have an adverse impact on the fund and its shareholders.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO_RiskMember_PassiveManagementRiskMember"
      id="ixv-5203">



      Passive Management Risk.

     The fund is managed with a passive investment strategy, attempting to track the performance of an unmanaged index of securities, regardless of the current or projected performance of the fund's index or of the actual securities included in the index. This differs from an actively managed fund, which typically seeks to outperform a benchmark index. As a result, the fund's performance could be lower than actively managed funds that may shift their portfolio assets to take advantage of market opportunities or lessen the impact of a market decline or a decline in the value of one or more issuers.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO_RiskMember_MidCapInvestingMember"
      id="ixv-5212">



      Mid Cap Investing.

     The value of securities of medium size, less well-known issuers can perform differently from the market as a whole and other types of stocks and can be more volatile than that of larger issuers.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO_RiskMember_SmallCapInvestingMember"
      id="ixv-5221">



      Small Cap Investing.

     The value of securities of smaller, less well-known issuers can perform differently from the market as a whole and other types of stocks and can be more volatile than that of larger issuers.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO_RiskMember_SecuritiesLendingRiskMember"
      id="ixv-5230">



      Securities Lending Risk.

     Securities lending involves the risk that the borrower may fail to return the securities loaned in a timely manner or at all. If the borrower defaults on its obligation to return the securities loaned because of insolvency or other reasons, a fund could experience delays and costs in recovering the securities loaned or in gaining access to the collateral.



   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO_RiskMember_RiskNotInsuredDepositoryInstitutionMember"
      id="ixv-5240">


     An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency

     .


   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO_RiskMember_RiskLoseMoneyMember"
      id="ixv-5248">


     &#160;

     You could lose money by investing in the fund.


   </oef:RiskTextBlock>
    <oef:BarChartAndPerformanceTableHeading
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5255">


     Performance


   </oef:BarChartAndPerformanceTableHeading>
    <oef:PerformanceNarrativeTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5260">


     The following information is intended to help you understand the risks of investing in the fund.


      The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.



     The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus.



      Past performance (before and after taxes) is not an indication of future performance.


     Visit



      www.fidelity.com


     for more recent performance information.

   </oef:PerformanceNarrativeTextBlock>
    <oef:PerformanceInformationIllustratesVariabilityOfReturns
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5265">

      The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.

     </oef:PerformanceInformationIllustratesVariabilityOfReturns>
    <oef:PerformancePastDoesNotIndicateFuture
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5272">

      Past performance (before and after taxes) is not an indication of future performance.

     </oef:PerformancePastDoesNotIndicateFuture>
    <oef:PerformanceAvailabilityWebSiteAddress
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5278">

      www.fidelity.com
     </oef:PerformanceAvailabilityWebSiteAddress>
    <oef:BarChartHeading
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5283">


     Year-by-Year Returns

   </oef:BarChartHeading>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_2016"
      decimals="INF"
      id="ixv-43135"
      unitRef="pure">0.1611</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_2017"
      decimals="INF"
      id="ixv-43136"
      unitRef="pure">0.1822</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_2018"
      decimals="INF"
      id="ixv-43137"
      unitRef="pure">-0.0936</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_2019"
      decimals="INF"
      id="ixv-43138"
      unitRef="pure">0.2800</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_2020"
      decimals="INF"
      id="ixv-43139"
      unitRef="pure">0.3216</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_2021"
      decimals="INF"
      id="ixv-43140"
      unitRef="pure">0.1241</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_2022"
      decimals="INF"
      id="ixv-43141"
      unitRef="pure">-0.2643</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_2023"
      decimals="INF"
      id="ixv-43142"
      unitRef="pure">0.2537</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_2024"
      decimals="INF"
      id="ixv-43143"
      unitRef="pure">0.1698</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_2025"
      decimals="INF"
      id="ixv-43144"
      unitRef="pure">0.1140</oef:AnnlRtrPct>
    <oef:HighestQuarterlyReturnLabel
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5394">
          &#160;&#160;&#160;Highest Quarter Return
        </oef:HighestQuarterlyReturnLabel>
    <oef:BarChartHighestQuarterlyReturn
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      decimals="4"
      id="ixv-43145"
      unitRef="pure">0.3118</oef:BarChartHighestQuarterlyReturn>
    <oef:BarChartHighestQuarterlyReturnDate
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5404">2020-06-30</oef:BarChartHighestQuarterlyReturnDate>
    <oef:LowestQuarterlyReturnLabel
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5409">
          &#160;&#160;&#160;Lowest Quarter Return
        </oef:LowestQuarterlyReturnLabel>
    <oef:BarChartLowestQuarterlyReturn
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      decimals="4"
      id="ixv-43146"
      unitRef="pure">-0.2804</oef:BarChartLowestQuarterlyReturn>
    <oef:BarChartLowestQuarterlyReturnDate
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5420">2020-03-31</oef:BarChartLowestQuarterlyReturnDate>
    <oef:YearToDateReturnLabel
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5425">
          &#160;&#160;&#160;Year-to-Date Return
        </oef:YearToDateReturnLabel>
    <oef:BarChartYearToDateReturn
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      decimals="4"
      id="ixv-43147"
      unitRef="pure">-0.0126</oef:BarChartYearToDateReturn>
    <oef:BarChartYearToDateReturnDate
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5436">2026-03-31</oef:BarChartYearToDateReturnDate>
    <oef:PerformanceTableHeading
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5441">


     Average Annual Returns


   </oef:PerformanceTableHeading>
    <oef:PerformanceTableNarrativeTextBlock
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5446">




      After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.



     Actual after-tax returns may differ depending on your individual circumstances.



      The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).





      Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.




   </oef:PerformanceTableNarrativeTextBlock>
    <oef:PerformanceTableUsesHighestFederalRate
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5449">

      After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.

     </oef:PerformanceTableUsesHighestFederalRate>
    <oef:PerformanceTableNotRelevantToTaxDeferred
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5456">

      The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).

     </oef:PerformanceTableNotRelevantToTaxDeferred>
    <oef:PerformanceTableExplanationAfterTaxHigher
      contextRef="Pid_S000006021_contentCd_SIF-I-PRO"
      id="ixv-5461">

      Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.

     </oef:PerformanceTableExplanationAfterTaxHigher>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006021_Cid_C000103355_ReturnBeforeTaxes_01"
      id="ixv-5506">
         Return Before Taxes
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_ReturnBeforeTaxes_01"
      decimals="4"
      id="ixv-43148"
      unitRef="pure">0.1140</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_ReturnBeforeTaxes_05"
      decimals="4"
      id="ixv-43149"
      unitRef="pure">0.0620</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_ReturnBeforeTaxes_10"
      decimals="4"
      id="ixv-43150"
      unitRef="pure">0.1102</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006021_Cid_C000103355_AfterTaxesOnDistributions_01"
      id="ixv-5521">
         Return After Taxes on Distributions
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_AfterTaxesOnDistributions_01"
      decimals="4"
      id="ixv-43151"
      unitRef="pure">0.1125</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_AfterTaxesOnDistributions_05"
      decimals="4"
      id="ixv-43152"
      unitRef="pure">0.0562</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_AfterTaxesOnDistributions_10"
      decimals="4"
      id="ixv-43153"
      unitRef="pure">0.1006</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006021_Cid_C000103355_AfterTaxesOnDistributionsAndSales_01"
      id="ixv-5536">
         Return After Taxes on Distributions and Sale of Fund Shares
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_AfterTaxesOnDistributionsAndSales_01"
      decimals="4"
      id="ixv-43154"
      unitRef="pure">0.0686</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_AfterTaxesOnDistributionsAndSales_05"
      decimals="4"
      id="ixv-43155"
      unitRef="pure">0.0474</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Cid_C000103355_AfterTaxesOnDistributionsAndSales_10"
      decimals="4"
      id="ixv-43156"
      unitRef="pure">0.0879</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006021_Indexid_WA008_contentCd_SIF-I-PRO_01"
      id="ixv-5552">
         Dow Jones U.S. Completion Total Stock Market Index&#x2120;
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Indexid_WA008_contentCd_SIF-I-PRO_01"
      decimals="4"
      id="ixv-43157"
      unitRef="pure">0.1132</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Indexid_WA008_contentCd_SIF-I-PRO_05"
      decimals="4"
      id="ixv-43158"
      unitRef="pure">0.0606</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Indexid_WA008_contentCd_SIF-I-PRO_10"
      decimals="4"
      id="ixv-43159"
      unitRef="pure">0.1087</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006021_Indexid_WA006_contentCd_SIF-I-PRO_01"
      id="ixv-5577">
         Dow Jones U.S. Total Stock Market Index&#x2120;
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Indexid_WA006_contentCd_SIF-I-PRO_01"
      decimals="4"
      id="ixv-43160"
      unitRef="pure">0.1705</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Indexid_WA006_contentCd_SIF-I-PRO_05"
      decimals="4"
      id="ixv-43161"
      unitRef="pure">0.1307</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006021_Indexid_WA006_contentCd_SIF-I-PRO_10"
      decimals="4"
      id="ixv-43162"
      unitRef="pure">0.1421</oef:AvgAnnlRtrPct>
    <oef:RiskReturnHeading
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5700">


     Fund Summary

     Fund:
     Fidelity&#xae; International Index Fund

   </oef:RiskReturnHeading>
    <oef:ObjectiveHeading
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5709">


     Investment Objective


   </oef:ObjectiveHeading>
    <oef:ObjectivePrimaryTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5714">


     Fidelity&#xae; International Index Fund seeks to provide investment results that correspond to the total return of foreign stock markets.


   </oef:ObjectivePrimaryTextBlock>
    <oef:ExpenseHeading
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5721">


     Fee Table


   </oef:ExpenseHeading>
    <oef:ExpenseNarrativeTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5727">


     The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions, which are not reflected in the tables and examples below.

   </oef:ExpenseNarrativeTextBlock>
    <oef:ShareholderFeesCaption
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5738">


     Shareholder fees


   </oef:ShareholderFeesCaption>
    <oef:ShareholderFeeOther
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      decimals="0"
      id="ixv-43163"
      unitRef="usd">0</oef:ShareholderFeeOther>
    <oef:OperatingExpensesCaption
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5753">


     Annual Operating Expenses


   </oef:OperatingExpensesCaption>
    <oef:ManagementFeesOverAssets
      contextRef="Pid_S000006023_Cid_C000103357"
      decimals="6"
      id="ixv-43164"
      unitRef="pure">0.00035</oef:ManagementFeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Pid_S000006023_Cid_C000103357"
      decimals="6"
      id="ixv-43165"
      unitRef="pure">0</oef:DistributionAndService12b1FeesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Pid_S000006023_Cid_C000103357"
      decimals="6"
      id="ixv-43166"
      unitRef="pure">0.00000</oef:OtherExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Pid_S000006023_Cid_C000103357"
      decimals="6"
      id="ixv-43167"
      unitRef="pure">0.00035</oef:ExpensesOverAssets>
    <oef:ExpenseExampleNarrativeTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5800">


     This
     example

     helps compare the cost of investing in the fund with the cost of investing in other funds.

     Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

   </oef:ExpenseExampleNarrativeTextBlock>
    <oef:ExpenseExampleYear01
      contextRef="Pid_S000006023_Cid_C000103357"
      decimals="0"
      id="ixv-43168"
      unitRef="usd">4</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Pid_S000006023_Cid_C000103357"
      decimals="0"
      id="ixv-43169"
      unitRef="usd">11</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleYear05
      contextRef="Pid_S000006023_Cid_C000103357"
      decimals="0"
      id="ixv-43170"
      unitRef="usd">20</oef:ExpenseExampleYear05>
    <oef:ExpenseExampleYear10
      contextRef="Pid_S000006023_Cid_C000103357"
      decimals="0"
      id="ixv-43171"
      unitRef="usd">45</oef:ExpenseExampleYear10>
    <oef:PortfolioTurnoverHeading
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5857">


     Portfolio Turnover


   </oef:PortfolioTurnoverHeading>
    <oef:PortfolioTurnoverTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5862">


     The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was



       4


     % of the average value of its portfolio.


   </oef:PortfolioTurnoverTextBlock>
    <oef:PortfolioTurnoverRate
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      decimals="4"
      id="ixv-43172"
      unitRef="pure">0.04</oef:PortfolioTurnoverRate>
    <oef:StrategyHeading
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5871">


     Principal Investment Strategies


   </oef:StrategyHeading>
    <oef:StrategyNarrativeTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5876">




        Normally investing at least 80% of assets in common stocks included in the MSCI EAFE Index, which represents the performance of foreign stock markets.

     The MSCI EAFE Index is a market capitalization-weighted index that
       is designed to measure the investable equity market performance for global investors in developed markets, excluding the U.S. &amp; Canada.

       Derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.

      Using statistical sampling techniques based on such factors as capitalization, industry exposures, dividend yield, price-to-earnings (P/E) ratio, price-to-book (P/B) ratio, earnings growth, and country weightings to attempt to replicate the returns of the MSCI EAFE Index.
      Lending securities to earn income for the fund.


   </oef:StrategyNarrativeTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO_RiskMember_StockMarketVolatilityMember"
      id="ixv-5901">



      Stock Market Volatility.

     Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market, including different market sectors, and different types of securities can react differently to these developments.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO_RiskMember_ForeignExposureMember"
      id="ixv-5910">



      Foreign Exposure.

     Foreign markets can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market.
     Foreign exchange rates also can be extremely volatile.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO_RiskMember_GeographicExposureToEuropeMember"
      id="ixv-5921">



      Geographic Exposure to Europe.

     Because the fund invests a meaningful portion of its assets in Europe, the fund's performance is expected to be closely tied to social, political, and economic conditions within Europe and to be more volatile than the performance of more geographically diversified funds.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO_RiskMember_GeographicExposureToJapanMember"
      id="ixv-5930">



      Geographic Exposure to Japan.

     Because the fund invests a meaningful portion of its assets in Japan, the fund's performance is expected to be closely tied to social, political, and economic conditions within Japan and to be more volatile than the performance of more geographically diversified funds.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO_RiskMember_IssuerSpecificChangesMember"
      id="ixv-5939">



      Issuer-Specific Changes.

     The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole.
     Changes in the financial condition of an issuer or counterparty (e.g., broker-dealer or other borrower in a securities lending transaction) can increase the risk of default by an issuer or counterparty, which can affect a security's or instrument's value or result in delays in recovering securities and/or capital from a counterparty.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO_RiskMember_CorrelationToIndexMember"
      id="ixv-5950">



      Correlation to Index.

     The performance of the fund and its underlying index may vary somewhat due to factors such as fees and expenses of the fund, transaction costs, sample selection, regulatory restrictions, and timing differences associated with additions to and deletions from the index. Errors in the construction or calculation of the index may occur from time to time and may not be identified and corrected for some period of time, which may have an adverse impact on the fund and its shareholders.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO_RiskMember_PassiveManagementRiskMember"
      id="ixv-5959">



      Passive Management Risk.

     The fund is managed with a passive investment strategy, attempting to track the performance of an unmanaged index of securities, regardless of the current or projected performance of the fund's index or of the actual securities included in the index. This differs from an actively managed fund, which typically seeks to outperform a benchmark index. As a result, the fund's performance could be lower than actively managed funds that may shift their portfolio assets to take advantage of market opportunities or lessen the impact of a market decline or a decline in the value of one or more issuers.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO_RiskMember_SecuritiesLendingRiskMember"
      id="ixv-5968">



      Securities Lending Risk.

     Securities lending involves the risk that the borrower may fail to return the securities loaned in a timely manner or at all. If the borrower defaults on its obligation to return the securities loaned because of insolvency or other reasons, a fund could experience delays and costs in recovering the securities loaned or in gaining access to the collateral.



   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO_RiskMember_RiskNotInsuredDepositoryInstitutionMember"
      id="ixv-5978">


     An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency

     .


   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO_RiskMember_RiskLoseMoneyMember"
      id="ixv-5986">


     &#160;

     You could lose money by investing in the fund.


   </oef:RiskTextBlock>
    <oef:BarChartAndPerformanceTableHeading
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5993">


     Performance


   </oef:BarChartAndPerformanceTableHeading>
    <oef:PerformanceNarrativeTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-5998">


     The following information is intended to help you understand the risks of investing in the fund.


      The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.



     The index description appears in the "Additional Index Information" section of the prospectus.



      Past performance (before and after taxes) is not an indication of future performance.


     Visit



      www.fidelity.com


     for more recent performance information.

   </oef:PerformanceNarrativeTextBlock>
    <oef:PerformanceInformationIllustratesVariabilityOfReturns
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6003">

      The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.

     </oef:PerformanceInformationIllustratesVariabilityOfReturns>
    <oef:PerformancePastDoesNotIndicateFuture
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6010">

      Past performance (before and after taxes) is not an indication of future performance.

     </oef:PerformancePastDoesNotIndicateFuture>
    <oef:PerformanceAvailabilityWebSiteAddress
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6016">

      www.fidelity.com
     </oef:PerformanceAvailabilityWebSiteAddress>
    <oef:BarChartHeading
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6021">


     Year-by-Year Returns

   </oef:BarChartHeading>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_2016"
      decimals="INF"
      id="ixv-43173"
      unitRef="pure">0.0134</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_2017"
      decimals="INF"
      id="ixv-43174"
      unitRef="pure">0.2538</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_2018"
      decimals="INF"
      id="ixv-43175"
      unitRef="pure">-0.1352</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_2019"
      decimals="INF"
      id="ixv-43176"
      unitRef="pure">0.2200</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_2020"
      decimals="INF"
      id="ixv-43177"
      unitRef="pure">0.0817</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_2021"
      decimals="INF"
      id="ixv-43178"
      unitRef="pure">0.1145</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_2022"
      decimals="INF"
      id="ixv-43179"
      unitRef="pure">-0.1424</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_2023"
      decimals="INF"
      id="ixv-43180"
      unitRef="pure">0.1831</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_2024"
      decimals="INF"
      id="ixv-43181"
      unitRef="pure">0.0371</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_2025"
      decimals="INF"
      id="ixv-43182"
      unitRef="pure">0.3196</oef:AnnlRtrPct>
    <oef:HighestQuarterlyReturnLabel
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6132">
          &#160;&#160;&#160;Highest Quarter Return
        </oef:HighestQuarterlyReturnLabel>
    <oef:BarChartHighestQuarterlyReturn
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      decimals="4"
      id="ixv-43183"
      unitRef="pure">0.1828</oef:BarChartHighestQuarterlyReturn>
    <oef:BarChartHighestQuarterlyReturnDate
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6142">2022-12-31</oef:BarChartHighestQuarterlyReturnDate>
    <oef:LowestQuarterlyReturnLabel
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6147">
          &#160;&#160;&#160;Lowest Quarter Return
        </oef:LowestQuarterlyReturnLabel>
    <oef:BarChartLowestQuarterlyReturn
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      decimals="4"
      id="ixv-43184"
      unitRef="pure">-0.2302</oef:BarChartLowestQuarterlyReturn>
    <oef:BarChartLowestQuarterlyReturnDate
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6158">2020-03-31</oef:BarChartLowestQuarterlyReturnDate>
    <oef:YearToDateReturnLabel
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6163">
          &#160;&#160;&#160;Year-to-Date Return
        </oef:YearToDateReturnLabel>
    <oef:BarChartYearToDateReturn
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      decimals="4"
      id="ixv-43185"
      unitRef="pure">0.0095</oef:BarChartYearToDateReturn>
    <oef:BarChartYearToDateReturnDate
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6173">2026-03-31</oef:BarChartYearToDateReturnDate>
    <oef:PerformanceTableHeading
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6178">


     Average Annual Returns


   </oef:PerformanceTableHeading>
    <oef:PerformanceTableNarrativeTextBlock
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6183">




      After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.



     Actual after-tax returns may differ depending on your individual circumstances.



      The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).





      Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.




   </oef:PerformanceTableNarrativeTextBlock>
    <oef:PerformanceTableUsesHighestFederalRate
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6186">

      After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.

     </oef:PerformanceTableUsesHighestFederalRate>
    <oef:PerformanceTableNotRelevantToTaxDeferred
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6193">

      The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).

     </oef:PerformanceTableNotRelevantToTaxDeferred>
    <oef:PerformanceTableExplanationAfterTaxHigher
      contextRef="Pid_S000006023_contentCd_SIF-I-PRO"
      id="ixv-6198">

      Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.

     </oef:PerformanceTableExplanationAfterTaxHigher>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006023_Cid_C000103357_ReturnBeforeTaxes_01"
      id="ixv-6243">
         Return Before Taxes
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_ReturnBeforeTaxes_01"
      decimals="4"
      id="ixv-43186"
      unitRef="pure">0.3196</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_ReturnBeforeTaxes_05"
      decimals="4"
      id="ixv-43187"
      unitRef="pure">0.0912</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_ReturnBeforeTaxes_10"
      decimals="4"
      id="ixv-43188"
      unitRef="pure">0.0842</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006023_Cid_C000103357_AfterTaxesOnDistributions_01"
      id="ixv-6258">
         Return After Taxes on Distributions
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_AfterTaxesOnDistributions_01"
      decimals="4"
      id="ixv-43189"
      unitRef="pure">0.3091</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_AfterTaxesOnDistributions_05"
      decimals="4"
      id="ixv-43190"
      unitRef="pure">0.0840</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_AfterTaxesOnDistributions_10"
      decimals="4"
      id="ixv-43191"
      unitRef="pure">0.0778</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006023_Cid_C000103357_AfterTaxesOnDistributionsAndSales_01"
      id="ixv-6273">
         Return After Taxes on Distributions and Sale of Fund Shares
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_AfterTaxesOnDistributionsAndSales_01"
      decimals="4"
      id="ixv-43192"
      unitRef="pure">0.1952</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_AfterTaxesOnDistributionsAndSales_05"
      decimals="4"
      id="ixv-43193"
      unitRef="pure">0.0711</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006023_Cid_C000103357_AfterTaxesOnDistributionsAndSales_10"
      decimals="4"
      id="ixv-43194"
      unitRef="pure">0.0677</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006023_Indexid_MS001_contentCd_SIF-I-PRO_01"
      id="ixv-6289">
         MSCI EAFE Index
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006023_Indexid_MS001_contentCd_SIF-I-PRO_01"
      decimals="4"
      id="ixv-43195"
      unitRef="pure">0.3159</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006023_Indexid_MS001_contentCd_SIF-I-PRO_05"
      decimals="4"
      id="ixv-43196"
      unitRef="pure">0.0917</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006023_Indexid_MS001_contentCd_SIF-I-PRO_10"
      decimals="4"
      id="ixv-43197"
      unitRef="pure">0.0842</oef:AvgAnnlRtrPct>
    <oef:RiskReturnHeading
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6411">


     Fund Summary

     Fund:
     Fidelity&#xae; Total Market Index Fund

   </oef:RiskReturnHeading>
    <oef:ObjectiveHeading
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6420">


     Investment Objective


   </oef:ObjectiveHeading>
    <oef:ObjectivePrimaryTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6425">


     Fidelity&#xae; Total Market Index Fund seeks to provide investment results that correspond to the total return of a broad range of United States stocks.


   </oef:ObjectivePrimaryTextBlock>
    <oef:ExpenseHeading
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6432">


     Fee Table


   </oef:ExpenseHeading>
    <oef:ExpenseNarrativeTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6438">


     The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions, which are not reflected in the tables and examples below.

   </oef:ExpenseNarrativeTextBlock>
    <oef:ShareholderFeesCaption
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6449">


     Shareholder fees


   </oef:ShareholderFeesCaption>
    <oef:ShareholderFeeOther
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      decimals="0"
      id="ixv-43198"
      unitRef="usd">0</oef:ShareholderFeeOther>
    <oef:OperatingExpensesCaption
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6464">


     Annual Operating Expenses


   </oef:OperatingExpensesCaption>
    <oef:ManagementFeesOverAssets
      contextRef="Pid_S000006026_Cid_C000103359"
      decimals="6"
      id="ixv-43199"
      unitRef="pure">0.00015</oef:ManagementFeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Pid_S000006026_Cid_C000103359"
      decimals="6"
      id="ixv-43200"
      unitRef="pure">0</oef:DistributionAndService12b1FeesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Pid_S000006026_Cid_C000103359"
      decimals="6"
      id="ixv-43201"
      unitRef="pure">0.00000</oef:OtherExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Pid_S000006026_Cid_C000103359"
      decimals="6"
      id="ixv-43202"
      unitRef="pure">0.00015</oef:ExpensesOverAssets>
    <oef:ExpenseExampleNarrativeTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6511">


     This
     example

     helps compare the cost of investing in the fund with the cost of investing in other funds.

     Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

   </oef:ExpenseExampleNarrativeTextBlock>
    <oef:ExpenseExampleYear01
      contextRef="Pid_S000006026_Cid_C000103359"
      decimals="0"
      id="ixv-43203"
      unitRef="usd">2</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Pid_S000006026_Cid_C000103359"
      decimals="0"
      id="ixv-43204"
      unitRef="usd">5</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleYear05
      contextRef="Pid_S000006026_Cid_C000103359"
      decimals="0"
      id="ixv-43205"
      unitRef="usd">8</oef:ExpenseExampleYear05>
    <oef:ExpenseExampleYear10
      contextRef="Pid_S000006026_Cid_C000103359"
      decimals="0"
      id="ixv-43206"
      unitRef="usd">19</oef:ExpenseExampleYear10>
    <oef:PortfolioTurnoverHeading
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6568">


     Portfolio Turnover


   </oef:PortfolioTurnoverHeading>
    <oef:PortfolioTurnoverTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6573">


     The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was



       3


     % of the average value of its portfolio.


   </oef:PortfolioTurnoverTextBlock>
    <oef:PortfolioTurnoverRate
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      decimals="4"
      id="ixv-43207"
      unitRef="pure">0.03</oef:PortfolioTurnoverRate>
    <oef:StrategyHeading
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6582">


     Principal Investment Strategies


   </oef:StrategyHeading>
    <oef:StrategyNarrativeTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6587">




        Normally investing at least 80% of assets in common stocks included in the Dow Jones U.S. Total Stock Market IndexSM, which represents the performance of a broad range of U.S. stocks.

     The Dow Jones U.S. Total Stock Market Index SM is a float-adjusted market capitalization-weighted index of approximately 5,000 common stocks of companies headquartered in the United States
        and listed on a primary U.S. exchange. The
       index represents the performance of a broad range of U.S. stocks.

       Derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.

      Using statistical sampling techniques based on such factors as capitalization, industry exposures, dividend yield, price-to-earnings (P/E) ratio, price-to-book (P/B) ratio, and earnings growth to attempt to replicate the returns of the Dow Jones U.S. Total Stock Market Index&#x2120;.
      Lending securities to earn income for the fund.

     The fund may operate as a non-diversified fund, as defined under the Investment Company Act of 1940 (1940 Act), to the approximate extent the index is non-diversified. The fund may therefore operate as non-diversified solely as a result of a change in relative market capitalization or index weighting of one or more constituents of the index.

   </oef:StrategyNarrativeTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO_RiskMember_StockMarketVolatilityMember"
      id="ixv-6622">



      Stock Market Volatility.

     Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market, including different market sectors, and different types of securities can react differently to these developments.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO_RiskMember_IssuerSpecificChangesMember"
      id="ixv-6631">



      Issuer-Specific Changes.

     The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole.
     Changes in the financial condition of an issuer or counterparty (e.g., broker-dealer or other borrower in a securities lending transaction) can increase the risk of default by an issuer or counterparty, which can affect a security's or instrument's value or result in delays in recovering securities and/or capital from a counterparty.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO_RiskMember_CorrelationToIndexMember"
      id="ixv-6642">



      Correlation to Index.

     The performance of the fund and its underlying index may vary somewhat due to factors such as fees and expenses of the fund, transaction costs, sample selection, regulatory restrictions, and timing differences associated with additions to and deletions from the index. Errors in the construction or calculation of the index may occur from time to time and may not be identified and corrected for some period of time, which may have an adverse impact on the fund and its shareholders.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO_RiskMember_PassiveManagementRiskMember"
      id="ixv-6651">



      Passive Management Risk.

     The fund is managed with a passive investment strategy, attempting to track the performance of an unmanaged index of securities, regardless of the current or projected performance of the fund's index or of the actual securities included in the index. This differs from an actively managed fund, which typically seeks to outperform a benchmark index. As a result, the fund's performance could be lower than actively managed funds that may shift their portfolio assets to take advantage of market opportunities or lessen the impact of a market decline or a decline in the value of one or more issuers.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO_RiskMember_SecuritiesLendingRiskMember"
      id="ixv-6660">



      Securities Lending Risk.

     Securities lending involves the risk that the borrower may fail to return the securities loaned in a timely manner or at all. If the borrower defaults on its obligation to return the securities loaned because of insolvency or other reasons, a fund could experience delays and costs in recovering the securities loaned or in gaining access to the collateral.



   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO_RiskMember_RiskNondiversifiedStatusMember"
      id="ixv-6670">


     In addition, the fund may operate as a non-diversified fund under the 1940 Act to the approximate extent the index is non-diversified. A non-diversified fund may invest a greater portion of its assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.


   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO_RiskMember_RiskNotInsuredDepositoryInstitutionMember"
      id="ixv-6675">


     An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency

     .


   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO_RiskMember_RiskLoseMoneyMember"
      id="ixv-6683">


     &#160;

     You could lose money by investing in the fund.


   </oef:RiskTextBlock>
    <oef:BarChartAndPerformanceTableHeading
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6690">


     Performance


   </oef:BarChartAndPerformanceTableHeading>
    <oef:PerformanceNarrativeTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6695">


     The following information is intended to help you understand the risks of investing in the fund.


      The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.



     The index description appears in the "Additional Index Information" section of the prospectus.



      Past performance (before and after taxes) is not an indication of future performance.


     Visit



      www.fidelity.com


     for more recent performance information.

   </oef:PerformanceNarrativeTextBlock>
    <oef:PerformanceInformationIllustratesVariabilityOfReturns
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6700">

      The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.

     </oef:PerformanceInformationIllustratesVariabilityOfReturns>
    <oef:PerformancePastDoesNotIndicateFuture
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6707">

      Past performance (before and after taxes) is not an indication of future performance.

     </oef:PerformancePastDoesNotIndicateFuture>
    <oef:PerformanceAvailabilityWebSiteAddress
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6713">

      www.fidelity.com
     </oef:PerformanceAvailabilityWebSiteAddress>
    <oef:BarChartHeading
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6718">


     Year-by-Year Returns

   </oef:BarChartHeading>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_2016"
      decimals="INF"
      id="ixv-43208"
      unitRef="pure">0.1268</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_2017"
      decimals="INF"
      id="ixv-43209"
      unitRef="pure">0.2118</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_2018"
      decimals="INF"
      id="ixv-43210"
      unitRef="pure">-0.0528</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_2019"
      decimals="INF"
      id="ixv-43211"
      unitRef="pure">0.3092</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_2020"
      decimals="INF"
      id="ixv-43212"
      unitRef="pure">0.2078</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_2021"
      decimals="INF"
      id="ixv-43213"
      unitRef="pure">0.2565</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_2022"
      decimals="INF"
      id="ixv-43214"
      unitRef="pure">-0.1951</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_2023"
      decimals="INF"
      id="ixv-43215"
      unitRef="pure">0.2612</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_2024"
      decimals="INF"
      id="ixv-43216"
      unitRef="pure">0.2388</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_2025"
      decimals="INF"
      id="ixv-43217"
      unitRef="pure">0.1705</oef:AnnlRtrPct>
    <oef:HighestQuarterlyReturnLabel
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6829">
          &#160;&#160;&#160;Highest Quarter Return
        </oef:HighestQuarterlyReturnLabel>
    <oef:BarChartHighestQuarterlyReturn
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      decimals="4"
      id="ixv-43218"
      unitRef="pure">0.2209</oef:BarChartHighestQuarterlyReturn>
    <oef:BarChartHighestQuarterlyReturnDate
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6839">2020-06-30</oef:BarChartHighestQuarterlyReturnDate>
    <oef:LowestQuarterlyReturnLabel
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6844">
          &#160;&#160;&#160;Lowest Quarter Return
        </oef:LowestQuarterlyReturnLabel>
    <oef:BarChartLowestQuarterlyReturn
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      decimals="4"
      id="ixv-43219"
      unitRef="pure">-0.2097</oef:BarChartLowestQuarterlyReturn>
    <oef:BarChartLowestQuarterlyReturnDate
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6855">2020-03-31</oef:BarChartLowestQuarterlyReturnDate>
    <oef:YearToDateReturnLabel
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6860">
          &#160;&#160;&#160;Year-to-Date Return
        </oef:YearToDateReturnLabel>
    <oef:BarChartYearToDateReturn
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      decimals="4"
      id="ixv-43220"
      unitRef="pure">-0.0398</oef:BarChartYearToDateReturn>
    <oef:BarChartYearToDateReturnDate
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6871">2026-03-31</oef:BarChartYearToDateReturnDate>
    <oef:PerformanceTableHeading
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6876">


     Average Annual Returns


   </oef:PerformanceTableHeading>
    <oef:PerformanceTableNarrativeTextBlock
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6881">




      After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.



     Actual after-tax returns may differ depending on your individual circumstances.



      The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).





      Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.




   </oef:PerformanceTableNarrativeTextBlock>
    <oef:PerformanceTableUsesHighestFederalRate
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6884">

      After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.

     </oef:PerformanceTableUsesHighestFederalRate>
    <oef:PerformanceTableNotRelevantToTaxDeferred
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6891">

      The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).

     </oef:PerformanceTableNotRelevantToTaxDeferred>
    <oef:PerformanceTableExplanationAfterTaxHigher
      contextRef="Pid_S000006026_contentCd_SIF-I-PRO"
      id="ixv-6896">

      Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.

     </oef:PerformanceTableExplanationAfterTaxHigher>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006026_Cid_C000103359_ReturnBeforeTaxes_01"
      id="ixv-6941">
         Return Before Taxes
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_ReturnBeforeTaxes_01"
      decimals="4"
      id="ixv-43221"
      unitRef="pure">0.1705</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_ReturnBeforeTaxes_05"
      decimals="4"
      id="ixv-43222"
      unitRef="pure">0.1309</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_ReturnBeforeTaxes_10"
      decimals="4"
      id="ixv-43223"
      unitRef="pure">0.1423</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006026_Cid_C000103359_AfterTaxesOnDistributions_01"
      id="ixv-6956">
         Return After Taxes on Distributions
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_AfterTaxesOnDistributions_01"
      decimals="4"
      id="ixv-43224"
      unitRef="pure">0.1676</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_AfterTaxesOnDistributions_05"
      decimals="4"
      id="ixv-43225"
      unitRef="pure">0.1273</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_AfterTaxesOnDistributions_10"
      decimals="4"
      id="ixv-43226"
      unitRef="pure">0.1375</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006026_Cid_C000103359_AfterTaxesOnDistributionsAndSales_01"
      id="ixv-6971">
         Return After Taxes on Distributions and Sale of Fund Shares
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_AfterTaxesOnDistributionsAndSales_01"
      decimals="4"
      id="ixv-43227"
      unitRef="pure">0.1028</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_AfterTaxesOnDistributionsAndSales_05"
      decimals="4"
      id="ixv-43228"
      unitRef="pure">0.1041</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006026_Cid_C000103359_AfterTaxesOnDistributionsAndSales_10"
      decimals="4"
      id="ixv-43229"
      unitRef="pure">0.1183</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006026_Indexid_WA006_contentCd_SIF-I-PRO_01"
      id="ixv-6987">
         Dow Jones U.S. Total Stock Market Index&#x2120;
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006026_Indexid_WA006_contentCd_SIF-I-PRO_01"
      decimals="4"
      id="ixv-43230"
      unitRef="pure">0.1705</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006026_Indexid_WA006_contentCd_SIF-I-PRO_05"
      decimals="4"
      id="ixv-43231"
      unitRef="pure">0.1307</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006026_Indexid_WA006_contentCd_SIF-I-PRO_10"
      decimals="4"
      id="ixv-43232"
      unitRef="pure">0.1421</oef:AvgAnnlRtrPct>
    <oef:RiskReturnHeading
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-10870">


     Fund Summary

     Fund:
     Fidelity&#xae; 500 Index Fund

   </oef:RiskReturnHeading>
    <oef:ObjectiveHeading
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-10879">


     Investment Objective


   </oef:ObjectiveHeading>
    <oef:ObjectivePrimaryTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-10884">


     Fidelity&#xae; 500 Index Fund seeks to provide investment results that correspond to the total return (i.e., the combination of capital changes and income) performance of common stocks publicly traded in the United States.


   </oef:ObjectivePrimaryTextBlock>
    <oef:ExpenseHeading
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-10889">


     Fee Table


   </oef:ExpenseHeading>
    <oef:ExpenseNarrativeTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-10895">


     The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions, which are not reflected in the tables and examples below.

   </oef:ExpenseNarrativeTextBlock>
    <oef:ShareholderFeesCaption
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-10906">


     Shareholder fees


   </oef:ShareholderFeesCaption>
    <oef:ShareholderFeeOther
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      decimals="0"
      id="ixv-43233"
      unitRef="usd">0</oef:ShareholderFeeOther>
    <oef:OperatingExpensesCaption
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-10921">


     Annual Operating Expenses


   </oef:OperatingExpensesCaption>
    <oef:ManagementFeesOverAssets
      contextRef="Pid_S000006027_Cid_C000100045"
      decimals="6"
      id="ixv-43234"
      unitRef="pure">0.00015</oef:ManagementFeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Pid_S000006027_Cid_C000100045"
      decimals="6"
      id="ixv-43235"
      unitRef="pure">0</oef:DistributionAndService12b1FeesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Pid_S000006027_Cid_C000100045"
      decimals="6"
      id="ixv-43236"
      unitRef="pure">0.00000</oef:OtherExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Pid_S000006027_Cid_C000100045"
      decimals="6"
      id="ixv-43237"
      unitRef="pure">0.00015</oef:ExpensesOverAssets>
    <oef:ExpenseExampleNarrativeTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-10968">


     This
     example

     helps compare the cost of investing in the fund with the cost of investing in other funds.

     Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

   </oef:ExpenseExampleNarrativeTextBlock>
    <oef:ExpenseExampleYear01
      contextRef="Pid_S000006027_Cid_C000100045"
      decimals="0"
      id="ixv-43238"
      unitRef="usd">2</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Pid_S000006027_Cid_C000100045"
      decimals="0"
      id="ixv-43239"
      unitRef="usd">5</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleYear05
      contextRef="Pid_S000006027_Cid_C000100045"
      decimals="0"
      id="ixv-43240"
      unitRef="usd">8</oef:ExpenseExampleYear05>
    <oef:ExpenseExampleYear10
      contextRef="Pid_S000006027_Cid_C000100045"
      decimals="0"
      id="ixv-43241"
      unitRef="usd">19</oef:ExpenseExampleYear10>
    <oef:PortfolioTurnoverHeading
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11025">


     Portfolio Turnover


   </oef:PortfolioTurnoverHeading>
    <oef:PortfolioTurnoverTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11030">


     The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was



       3


     % of the average value of its portfolio.


   </oef:PortfolioTurnoverTextBlock>
    <oef:PortfolioTurnoverRate
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      decimals="4"
      id="ixv-43242"
      unitRef="pure">0.03</oef:PortfolioTurnoverRate>
    <oef:StrategyHeading
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11039">


     Principal Investment Strategies


   </oef:StrategyHeading>
    <oef:StrategyNarrativeTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11044">




        Normally investing at least 80% of assets in common stocks included in the S&amp;P 500&#xae; Index.

     The S&amp;P 500 &#xae; Index is a
       market capitalization-weighted index of 500 common stocks that represents the performance of
       the large-capitalization segment of the U.S. market.


        Derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.
      Lending securities to earn income for the fund.

     The fund may operate as a non-diversified fund, as defined under the Investment Company Act of 1940 (1940 Act), to the approximate extent the index is non-diversified. The fund may therefore operate as non-diversified solely as a result of a change in relative market capitalization or index weighting of one or more constituents of the index.

   </oef:StrategyNarrativeTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO_RiskMember_StockMarketVolatilityMember"
      id="ixv-11076">



      Stock Market Volatility.

     Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market, including different market sectors, and different types of securities can react differently to these developments.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO_RiskMember_IssuerSpecificChangesMember"
      id="ixv-11085">



      Issuer-Specific Changes.

     The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole.
     Changes in the financial condition of an issuer or counterparty (e.g., broker-dealer or other borrower in a securities lending transaction) can increase the risk of default by an issuer or counterparty, which can affect a security's or instrument's value or result in delays in recovering securities and/or capital from a counterparty.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO_RiskMember_CorrelationToIndexMember"
      id="ixv-11096">



      Correlation to Index.

     The performance of the fund and its underlying index may vary somewhat due to factors such as fees and expenses of the fund, transaction costs, sample selection, regulatory restrictions, and timing differences associated with additions to and deletions from the index. Errors in the construction or calculation of the index may occur from time to time and may not be identified and corrected for some period of time, which may have an adverse impact on the fund and its shareholders.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO_RiskMember_PassiveManagementRiskMember"
      id="ixv-11105">



      Passive Management Risk.

     The fund is managed with a passive investment strategy, attempting to track the performance of an unmanaged index of securities, regardless of the current or projected performance of the fund's index or of the actual securities included in the index. This differs from an actively managed fund, which typically seeks to outperform a benchmark index. As a result, the fund's performance could be lower than actively managed funds that may shift their portfolio assets to take advantage of market opportunities or lessen the impact of a market decline or a decline in the value of one or more issuers.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO_RiskMember_SecuritiesLendingRiskMember"
      id="ixv-11114">



      Securities Lending Risk.

     Securities lending involves the risk that the borrower may fail to return the securities loaned in a timely manner or at all. If the borrower defaults on its obligation to return the securities loaned because of insolvency or other reasons, a fund could experience delays and costs in recovering the securities loaned or in gaining access to the collateral.



   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO_RiskMember_RiskNondiversifiedStatusMember"
      id="ixv-11124">


     In addition, the fund may operate as a non-diversified fund under the 1940 Act to the approximate extent the index is non-diversified. A non-diversified fund may invest a greater portion of its assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.


   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO_RiskMember_RiskNotInsuredDepositoryInstitutionMember"
      id="ixv-11129">


     An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency

     .


   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO_RiskMember_RiskLoseMoneyMember"
      id="ixv-11137">


     &#160;

     You could lose money by investing in the fund.


   </oef:RiskTextBlock>
    <oef:BarChartAndPerformanceTableHeading
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11144">


     Performance


   </oef:BarChartAndPerformanceTableHeading>
    <oef:PerformanceNarrativeTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11149">


     The following information is intended to help you understand the risks of investing in the fund.


      The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.



     The index description appears in the "Additional Index Information" section of the prospectus.



      Past performance (before and after taxes) is not an indication of future performance.


     Visit



      www.fidelity.com


     for more recent performance information.

   </oef:PerformanceNarrativeTextBlock>
    <oef:PerformanceInformationIllustratesVariabilityOfReturns
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11154">

      The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index over various periods of time.

     </oef:PerformanceInformationIllustratesVariabilityOfReturns>
    <oef:PerformancePastDoesNotIndicateFuture
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11161">

      Past performance (before and after taxes) is not an indication of future performance.

     </oef:PerformancePastDoesNotIndicateFuture>
    <oef:PerformanceAvailabilityWebSiteAddress
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11167">

      www.fidelity.com
     </oef:PerformanceAvailabilityWebSiteAddress>
    <oef:BarChartHeading
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11172">


     Year-by-Year Returns

   </oef:BarChartHeading>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_2016"
      decimals="INF"
      id="ixv-43243"
      unitRef="pure">0.1197</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_2017"
      decimals="INF"
      id="ixv-43244"
      unitRef="pure">0.2181</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_2018"
      decimals="INF"
      id="ixv-43245"
      unitRef="pure">-0.0440</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_2019"
      decimals="INF"
      id="ixv-43246"
      unitRef="pure">0.3147</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_2020"
      decimals="INF"
      id="ixv-43247"
      unitRef="pure">0.1840</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_2021"
      decimals="INF"
      id="ixv-43248"
      unitRef="pure">0.2869</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_2022"
      decimals="INF"
      id="ixv-43249"
      unitRef="pure">-0.1813</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_2023"
      decimals="INF"
      id="ixv-43250"
      unitRef="pure">0.2629</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_2024"
      decimals="INF"
      id="ixv-43251"
      unitRef="pure">0.2500</oef:AnnlRtrPct>
    <oef:AnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_2025"
      decimals="INF"
      id="ixv-43252"
      unitRef="pure">0.1786</oef:AnnlRtrPct>
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          &#160;&#160;&#160;Highest Quarter Return
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      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      decimals="4"
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      unitRef="pure">0.2053</oef:BarChartHighestQuarterlyReturn>
    <oef:BarChartHighestQuarterlyReturnDate
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11293">2020-06-30</oef:BarChartHighestQuarterlyReturnDate>
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      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
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          &#160;&#160;&#160;Lowest Quarter Return
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      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      decimals="4"
      id="ixv-43254"
      unitRef="pure">-0.1959</oef:BarChartLowestQuarterlyReturn>
    <oef:BarChartLowestQuarterlyReturnDate
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11309">2020-03-31</oef:BarChartLowestQuarterlyReturnDate>
    <oef:YearToDateReturnLabel
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
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          &#160;&#160;&#160;Year-to-Date Return
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      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      decimals="4"
      id="ixv-43255"
      unitRef="pure">-0.0434</oef:BarChartYearToDateReturn>
    <oef:BarChartYearToDateReturnDate
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11325">2026-03-31</oef:BarChartYearToDateReturnDate>
    <oef:PerformanceTableHeading
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11330">


     Average Annual Returns


   </oef:PerformanceTableHeading>
    <oef:PerformanceTableNarrativeTextBlock
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11335">




      After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.



     Actual after-tax returns may differ depending on your individual circumstances.



      The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).





      Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.




   </oef:PerformanceTableNarrativeTextBlock>
    <oef:PerformanceTableUsesHighestFederalRate
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11338">

      After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.

     </oef:PerformanceTableUsesHighestFederalRate>
    <oef:PerformanceTableNotRelevantToTaxDeferred
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11345">

      The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).

     </oef:PerformanceTableNotRelevantToTaxDeferred>
    <oef:PerformanceTableExplanationAfterTaxHigher
      contextRef="Pid_S000006027_contentCd_U5I-U5A-PRO"
      id="ixv-11350">

      Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.

     </oef:PerformanceTableExplanationAfterTaxHigher>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006027_Cid_C000100045_ReturnBeforeTaxes_01"
      id="ixv-11395">
         Return Before Taxes
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_ReturnBeforeTaxes_01"
      decimals="4"
      id="ixv-43256"
      unitRef="pure">0.1786</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_ReturnBeforeTaxes_05"
      decimals="4"
      id="ixv-43257"
      unitRef="pure">0.1441</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_ReturnBeforeTaxes_10"
      decimals="4"
      id="ixv-43258"
      unitRef="pure">0.1481</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006027_Cid_C000100045_AfterTaxesOnDistributions_01"
      id="ixv-11410">
         Return After Taxes on Distributions
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_AfterTaxesOnDistributions_01"
      decimals="4"
      id="ixv-43259"
      unitRef="pure">0.1751</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_AfterTaxesOnDistributions_05"
      decimals="4"
      id="ixv-43260"
      unitRef="pure">0.1402</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_AfterTaxesOnDistributions_10"
      decimals="4"
      id="ixv-43261"
      unitRef="pure">0.1430</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006027_Cid_C000100045_AfterTaxesOnDistributionsAndSales_01"
      id="ixv-11425">
         Return After Taxes on Distributions and Sale of Fund Shares
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_AfterTaxesOnDistributionsAndSales_01"
      decimals="4"
      id="ixv-43262"
      unitRef="pure">0.1077</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_AfterTaxesOnDistributionsAndSales_05"
      decimals="4"
      id="ixv-43263"
      unitRef="pure">0.1150</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006027_Cid_C000100045_AfterTaxesOnDistributionsAndSales_10"
      decimals="4"
      id="ixv-43264"
      unitRef="pure">0.1233</oef:AvgAnnlRtrPct>
    <oef:AverageAnnualReturnLabel
      contextRef="Pid_S000006027_Indexid_SP001_contentCd_U5I-U5A-PRO_01"
      id="ixv-11441">
         S&amp;P 500&#xae; Index
        </oef:AverageAnnualReturnLabel>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006027_Indexid_SP001_contentCd_U5I-U5A-PRO_01"
      decimals="4"
      id="ixv-43265"
      unitRef="pure">0.1788</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006027_Indexid_SP001_contentCd_U5I-U5A-PRO_05"
      decimals="4"
      id="ixv-43266"
      unitRef="pure">0.1442</oef:AvgAnnlRtrPct>
    <oef:AvgAnnlRtrPct
      contextRef="Pid_S000006027_Indexid_SP001_contentCd_U5I-U5A-PRO_10"
      decimals="4"
      id="ixv-43267"
      unitRef="pure">0.1482</oef:AvgAnnlRtrPct>
    <oef:RiskReturnHeading
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13450">


     Fund Summary

     Fund:
     Fidelity Flex&#xae; Large Cap Focused Index Fund

   </oef:RiskReturnHeading>
    <oef:ObjectiveHeading
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     Investment Objective


   </oef:ObjectiveHeading>
    <oef:ObjectivePrimaryTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13464">


     Fidelity Flex&#xae; Large Cap Focused Index Fund seeks to provide investment results that correspond to the total return of stocks of large capitalization U.S. companies.


   </oef:ObjectivePrimaryTextBlock>
    <oef:ExpenseHeading
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13469">


     Fee Table


   </oef:ExpenseHeading>
    <oef:ExpenseNarrativeTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13475">


     The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund. You may pay other fees, such as brokerage commissions, which are not reflected in the tables and examples below.

   </oef:ExpenseNarrativeTextBlock>
    <oef:ShareholderFeesCaption
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13487">


     Shareholder fees


   </oef:ShareholderFeesCaption>
    <oef:ShareholderFeeOther
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      decimals="0"
      id="ixv-43268"
      unitRef="usd">0</oef:ShareholderFeeOther>
    <oef:OperatingExpensesCaption
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13502">


     Annual Operating Expenses


   </oef:OperatingExpensesCaption>
    <oef:ManagementFeesOverAssets
      contextRef="Pid_S000093535_Cid_C000261866"
      decimals="6"
      id="ixv-43269"
      unitRef="pure">0.0000</oef:ManagementFeesOverAssets>
    <oef:DistributionAndService12b1FeesOverAssets
      contextRef="Pid_S000093535_Cid_C000261866"
      decimals="6"
      id="ixv-43270"
      unitRef="pure">0</oef:DistributionAndService12b1FeesOverAssets>
    <oef:OtherExpensesOverAssets
      contextRef="Pid_S000093535_Cid_C000261866"
      decimals="6"
      id="footnoteS000093535FXL-PROAOE_AC000261866_OE"
      unitRef="pure">0.0000</oef:OtherExpensesOverAssets>
    <oef:ExpensesOverAssets
      contextRef="Pid_S000093535_Cid_C000261866"
      decimals="6"
      id="footnoteS000093535FXL-PROAOE_BC000261866_TE"
      unitRef="pure">0.0000</oef:ExpensesOverAssets>
    <oef:OtherExpensesNewFundBasedOnEstimates
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13556">

      Based on estimated amounts for the current fiscal year.

     </oef:OtherExpensesNewFundBasedOnEstimates>
    <oef:ExpenseExampleNarrativeTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13568">


     This
     example

     helps compare the cost of investing in the fund with the cost of investing in other funds.

     Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. This example does not include any fees paid at the fee-based account or plan level. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

   </oef:ExpenseExampleNarrativeTextBlock>
    <oef:ExpenseExampleYear01
      contextRef="Pid_S000093535_Cid_C000261866"
      decimals="0"
      id="ixv-43273"
      unitRef="usd">0</oef:ExpenseExampleYear01>
    <oef:ExpenseExampleYear03
      contextRef="Pid_S000093535_Cid_C000261866"
      decimals="0"
      id="ixv-43274"
      unitRef="usd">0</oef:ExpenseExampleYear03>
    <oef:ExpenseExampleYear05
      contextRef="Pid_S000093535_Cid_C000261866"
      decimals="0"
      id="ixv-43275"
      unitRef="usd">0</oef:ExpenseExampleYear05>
    <oef:ExpenseExampleYear10
      contextRef="Pid_S000093535_Cid_C000261866"
      decimals="0"
      id="ixv-43276"
      unitRef="usd">0</oef:ExpenseExampleYear10>
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      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13625">


     Portfolio Turnover


   </oef:PortfolioTurnoverHeading>
    <oef:PortfolioTurnoverTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13630">


     The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. For the period from July 24, 2025 to February 28, 2026, the fund's portfolio turnover rate was



       4


     % (annualized) of the average value of its portfolio.


   </oef:PortfolioTurnoverTextBlock>
    <oef:PortfolioTurnoverRate
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      decimals="4"
      id="ixv-43277"
      unitRef="pure">0.04</oef:PortfolioTurnoverRate>
    <oef:StrategyHeading
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13639">


     Principal Investment Strategies


   </oef:StrategyHeading>
    <oef:StrategyNarrativeTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13644">




        Normally investing at least 80% of assets in securities of large capitalization companies included in the Fidelity U.S. Large Cap Focused IndexSM.

     The Fidelity U.S. Large Cap Focused Index SM is designed to reflect the performance of stocks of large capitalization U.S. companies. Large capitalization stocks are considered to be stocks of the largest 500 U.S. companies based on float-adjusted market capitalization.
     The Fidelity U.S. Large Cap Focused Index SM was created by Fidelity Product Services LLC (FPS) using a rules-based proprietary index methodology that includes all U.S. stocks meeting certain market capitalization, liquidity and investability requirements.

       Derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives.

      Using statistical sampling techniques based on such factors as capitalization, industry exposures, dividend yield, price-to-earnings (P/E) ratio, price-to-book (P/B) ratio, and earnings growth to attempt to replicate the returns of the Fidelity U.S. Large Cap Focused
        Index&#x2120;.
      Lending securities to earn income for the fund.


   </oef:StrategyNarrativeTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO_RiskMember_StockMarketVolatilityMember"
      id="ixv-13679">



      Stock Market Volatility.

     Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market, including different market sectors, and different types of securities can react differently to these developments.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO_RiskMember_IssuerSpecificChangesMember"
      id="ixv-13688">



      Issuer-Specific Changes.

     The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole.
     Changes in the financial condition of an issuer or counterparty (e.g., broker-dealer or other borrower in a securities lending transaction) can increase the risk of default by an issuer or counterparty, which can affect a security's or instrument's value or result in delays in recovering securities and/or capital from a counterparty.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO_RiskMember_CorrelationToIndexMember"
      id="ixv-13699">



      Correlation to Index.

     The performance of the fund and its underlying index may vary somewhat due to factors such as fees and expenses of the fund, transaction costs, sample selection, regulatory restrictions, and timing differences associated with additions to and deletions from the index. Errors in the construction or calculation of the index may occur from time to time and may not be identified and corrected for some period of time, which may have an adverse impact on the fund and its shareholders.

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO_RiskMember_PassiveManagementRiskMember"
      id="ixv-13708">



      Passive Management Risk.

     The fund is managed with a passive investment strategy, attempting to track the performance of an unmanaged index of securities, regardless of the current or projected performance of the fund's index or of the actual securities included in the index. This differs from an actively managed fund, which typically seeks to outperform a benchmark index. As a result, the fund's performance could be lower than actively managed funds that may shift their portfolio assets to take advantage of market opportunities or lessen the impact of a market decline or a decline in the value of one or more issuers.
     The fund will be concentrated to approximately the same extent that the fund's index concentrates in the securities of issuers in a particular industry
       .

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO_RiskMember_RulesBasedStrategyRiskMember"
      id="ixv-13721">



      Rules-Based Strategy Risk.

     Although the index uses a rules-based proprietary index methodology, there is no guarantee that this methodology will be successful.&#160;

   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO_RiskMember_SecuritiesLendingRiskMember"
      id="ixv-13731">



      Securities Lending Risk.

     Securities lending involves the risk that the borrower may fail to return the securities loaned in a timely manner or at all. If the borrower defaults on its obligation to return the securities loaned because of insolvency or other reasons, a fund could experience delays and costs in recovering the securities loaned or in gaining access to the collateral.



   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO_RiskMember_RiskNotInsuredDepositoryInstitutionMember"
      id="ixv-13741">


     An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency

     .


   </oef:RiskTextBlock>
    <oef:RiskTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO_RiskMember_RiskLoseMoneyMember"
      id="ixv-13749">


     &#160;

     You could lose money by investing in the fund.


   </oef:RiskTextBlock>
    <oef:BarChartAndPerformanceTableHeading
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13756">


     Performance


   </oef:BarChartAndPerformanceTableHeading>
    <oef:PerformanceNarrativeTextBlock
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13761">




      Performance history will be available for the fund after the fund has been in operation for one calendar year.



   </oef:PerformanceNarrativeTextBlock>
    <oef:PerformanceOneYearOrLess
      contextRef="Pid_S000093535_contentCd_FXL-PRO"
      id="ixv-13764">

      Performance history will be available for the fund after the fund has been in operation for one calendar year.

     </oef:PerformanceOneYearOrLess>
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        <link:footnote id="footnoteS000056363Z5I-PROAOE_A" xlink:label="footnoteS000056363Z5I-PROAOE_A" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:div style="padding:2px"><xhtml:span> </xhtml:span><xhtml:span
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        <link:footnote id="footnoteZ5I-PROS000056363AAR_B" xlink:label="footnoteZ5I-PROS000056363AAR_B" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:div style="padding:2px"><xhtml:span> </xhtml:span><xhtml:span
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      style="font-family:Arial; font-size:4.5pt; vertical-align:3pt; ">B</xhtml:span><xhtml:span> </xhtml:span><xhtml:span
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      style="font-family:Arial; font-size:8.5pt; font-style:italic; ">The inception date for the index was after the fund commenced operations, and returns for this time period are not yet available.</xhtml:span><xhtml:span> </xhtml:span></xhtml:div></link:footnote>
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        <link:footnote id="footnoteS000093535FXL-PROAOE_A" xlink:label="footnoteS000093535FXL-PROAOE_A" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:div style="padding:2px"><xhtml:span> </xhtml:span><xhtml:span style="font-family:Arial; font-size:4.5pt; vertical-align:3pt">A</xhtml:span><xhtml:span> </xhtml:span><xhtml:span> </xhtml:span><xhtml:span style="font-family:Arial; font-size:8.5pt">Based on estimated amounts for the current fiscal year.</xhtml:span><xhtml:span> </xhtml:span><xhtml:span> </xhtml:span></xhtml:div></link:footnote>
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        <link:footnote id="footnoteS000093535FXL-PROAOE_B" xlink:label="footnoteS000093535FXL-PROAOE_B" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:div style="padding:2px"><xhtml:span> </xhtml:span><xhtml:span style="font-family:Arial; font-size:4.5pt; vertical-align:3pt">B</xhtml:span><xhtml:span> </xhtml:span><xhtml:span style="font-family:Arial; font-size:8.5pt">The fund is available only to certain fee-based accounts and advisory programs offered by Fidelity. Advisory account clients, retirement plans, plan sponsors and/or plan participants typically pay an advisory fee that generally covers investment advisory and administrative services.</xhtml:span><xhtml:span> </xhtml:span></xhtml:div></link:footnote>
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