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    <unit id="usd">
        <measure>iso4217:USD</measure>
    </unit>
    <unit id="pure">
        <measure>pure</measure>
    </unit>
    <dei:DocumentType contextRef="Trust">485BPOS</dei:DocumentType>
    <dei:DocumentPeriodEndDate contextRef="Trust">2020-07-31</dei:DocumentPeriodEndDate>
    <dei:AmendmentFlag contextRef="Trust">false</dei:AmendmentFlag>
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    <dei:EntityRegistrantName contextRef="Trust">FIDELITY SALEM STREET TRUST</dei:EntityRegistrantName>
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      decimals="INF"
      unitRef="pure">0.1711</rr:AnnualReturn2012>
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      decimals="INF"
      unitRef="pure">0.0137</rr:AnnualReturn2013>
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      unitRef="pure">0.0439</rr:AnnualReturn2015>
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      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">0.0660</rr:AnnualReturn2016>
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      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">0.0375</rr:AnnualReturn2017>
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      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">-0.0421</rr:AnnualReturn2018>
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      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">0.2302</rr:AnnualReturn2019>
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      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">0.0373</rr:AnnualReturn2017>
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      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">-0.0418</rr:AnnualReturn2018>
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      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">0.2306</rr:AnnualReturn2019>
    <rr:AnnualReturn2016
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">0.1462</rr:AnnualReturn2016>
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      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">0.1840</rr:AnnualReturn2017>
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      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">-0.0925</rr:AnnualReturn2018>
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      decimals="INF"
      unitRef="pure">0.2953</rr:AnnualReturn2019>
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      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">0.2174</rr:AnnualReturn2017>
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      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">-0.0436</rr:AnnualReturn2018>
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      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">0.3153</rr:AnnualReturn2019>
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      contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="INF"
      unitRef="pure">-0.0140</rr:AnnualReturn2018>
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      contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="INF"
      unitRef="pure">0.2416</rr:AnnualReturn2019>
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      contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">0.0782</rr:AnnualReturn2016>
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      decimals="INF"
      unitRef="pure">0.2575</rr:AnnualReturn2017>
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      decimals="INF"
      unitRef="pure">-0.0275</rr:AnnualReturn2018>
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      contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="INF"
      unitRef="pure">0.3407</rr:AnnualReturn2019>
    <rr:AnnualReturn2018
      contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="INF"
      unitRef="pure">-0.1071</rr:AnnualReturn2018>
    <rr:AnnualReturn2019
      contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="INF"
      unitRef="pure">0.2909</rr:AnnualReturn2019>
    <rr:RiskReturnHeading contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">Fund Summary
Fund:
Fidelity&#xae; Real Estate Index Fund



</rr:RiskReturnHeading>
    <rr:ObjectiveHeading contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">Investment Objective

</rr:ObjectiveHeading>
    <rr:ObjectivePrimaryTextBlock contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">The fund seeks to provide investment results that correspond to the total return of equity REITs and other real estate-related investments.

</rr:ObjectivePrimaryTextBlock>
    <rr:ExpenseHeading contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">Fee Table

</rr:ExpenseHeading>
    <rr:ExpenseNarrativeTextBlock contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

</rr:ExpenseNarrativeTextBlock>
    <rr:ShareholderFeesCaption contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">Shareholder fees

</rr:ShareholderFeesCaption>
    <rr:ShareholderFeeOther
      contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">0</rr:ShareholderFeeOther>
    <rr:OperatingExpensesCaption contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">Annual Operating Expenses
(expenses that you pay each year as a % of the value of your investment)

</rr:OperatingExpensesCaption>
    <rr:ManagementFeesOverAssets
      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0007</rr:ManagementFeesOverAssets>
    <rr:DistributionAndService12b1FeesOverAssets
      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0</rr:DistributionAndService12b1FeesOverAssets>
    <rr:OtherExpensesOverAssets
      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0000</rr:OtherExpensesOverAssets>
    <rr:ExpensesOverAssets
      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0007</rr:ExpensesOverAssets>
    <rr:ExpenseExampleNarrativeTextBlock contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">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 your shareholder 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:

</rr:ExpenseExampleNarrativeTextBlock>
    <rr:ExpenseExampleYear01
      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">7</rr:ExpenseExampleYear01>
    <rr:ExpenseExampleYear03
      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">23</rr:ExpenseExampleYear03>
    <rr:ExpenseExampleYear05
      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">40</rr:ExpenseExampleYear05>
    <rr:ExpenseExampleYear10
      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">90</rr:ExpenseExampleYear10>
    <rr:PortfolioTurnoverHeading contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">Portfolio Turnover

</rr:PortfolioTurnoverHeading>
    <rr:PortfolioTurnoverTextBlock contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">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 26% of the average value of its portfolio.

</rr:PortfolioTurnoverTextBlock>
    <rr:PortfolioTurnoverRate
      contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.26</rr:PortfolioTurnoverRate>
    <rr:StrategyHeading contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">Principal Investment Strategies

</rr:StrategyHeading>
    <rr:StrategyNarrativeTextBlock contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">

Prior to December 1, 2020, normally investing at least 80% of assets in securities included in the Dow Jones U.S. Select Real Estate Securities Index&#x2120; (the Index).


Effective December 1, 2020, normally investing at least 80% of assets in securities included in the MSCI US IMI Real Estate 25/25 Index (the Index).



Lending securities to earn income for the fund.


</rr:StrategyNarrativeTextBlock>
    <rr:StrategyPortfolioConcentration contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">Prior to December 1, 2020, normally investing at least 80% of assets in securities included in the Dow Jones U.S. Select Real Estate Securities Index&#x2120; (the Index).


Effective December 1, 2020, normally investing at least 80% of assets in securities included in the MSCI US IMI Real Estate 25/25 Index (the Index).</rr:StrategyPortfolioConcentration>
    <rr:RiskHeading contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">Principal Investment Risks

</rr:RiskHeading>
    <rr:RiskNarrativeTextBlock contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">

Stock Market Volatility.&#160;
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.



Real Estate Industry Concentration.&#160;
Changes in real estate values or economic downturns can have a significant negative effect on issuers in the real estate industry. The value of securities of issuers in the real estate industry can be affected by changes in real estate values and rental income, property taxes, interest rates, tax and regulatory requirements, and the management skill and creditworthiness of the issuer.



Issuer-Specific Changes.&#160;
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.



Correlation to Index.&#160;
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.



Passive Management Risk.&#160;
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&#x92;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&#x92;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.



Securities Lending Risk.&#160;
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.


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. You could lose money by investing in the fund.

</rr:RiskNarrativeTextBlock>
    <rr:RiskNotInsuredDepositoryInstitution contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">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.</rr:RiskNotInsuredDepositoryInstitution>
    <rr:RiskLoseMoney contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">You could lose money by investing in the fund.</rr:RiskLoseMoney>
    <rr:BarChartAndPerformanceTableHeading contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">Performance

</rr:BarChartAndPerformanceTableHeading>
    <rr:PerformanceNarrativeTextBlock contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">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.

</rr:PerformanceNarrativeTextBlock>
    <rr:PerformanceInformationIllustratesVariabilityOfReturns contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">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.</rr:PerformanceInformationIllustratesVariabilityOfReturns>
    <rr:PerformancePastDoesNotIndicateFuture contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">Past performance (before and after taxes) is not an indication of future performance.</rr:PerformancePastDoesNotIndicateFuture>
    <rr:PerformanceAvailabilityWebSiteAddress contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">www.fidelity.com </rr:PerformanceAvailabilityWebSiteAddress>
    <rr:BarChartHeading contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">Year-by-Year Returns

</rr:BarChartHeading>
    <rr:HighestQuarterlyReturnLabel contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member">Highest Quarter Return</rr:HighestQuarterlyReturnLabel>
    <rr:BarChartHighestQuarterlyReturn
      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.1572</rr:BarChartHighestQuarterlyReturn>
    <rr:BarChartHighestQuarterlyReturnDate contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member">2019-03-31</rr:BarChartHighestQuarterlyReturnDate>
    <rr:LowestQuarterlyReturnLabel contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member">Lowest Quarter Return</rr:LowestQuarterlyReturnLabel>
    <rr:BarChartLowestQuarterlyReturn
      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">-0.1002</rr:BarChartLowestQuarterlyReturn>
    <rr:BarChartLowestQuarterlyReturnDate contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member">2015-06-30</rr:BarChartLowestQuarterlyReturnDate>
    <rr:YearToDateReturnLabel contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member">Year-to-Date Return</rr:YearToDateReturnLabel>
    <rr:BarChartYearToDateReturn
      contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">-0.2195</rr:BarChartYearToDateReturn>
    <rr:BarChartYearToDateReturnDate contextRef="S000033639_C000103377_D0731FidelityRealEstateIndexFundPRO08Member">2020-06-30</rr:BarChartYearToDateReturnDate>
    <rr:PerformanceTableHeading contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">Average Annual Returns

</rr:PerformanceTableHeading>
    <rr:PerformanceTableNarrativeTextBlock contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">
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.

</rr:PerformanceTableNarrativeTextBlock>
    <rr:PerformanceTableUsesHighestFederalRate contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">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.</rr:PerformanceTableUsesHighestFederalRate>
    <rr:PerformanceTableNotRelevantToTaxDeferred contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">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).</rr:PerformanceTableNotRelevantToTaxDeferred>
    <rr:PerformanceTableExplanationAfterTaxHigher contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">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.</rr:PerformanceTableExplanationAfterTaxHigher>
    <rr:AverageAnnualReturnLabel contextRef="S000033639_C000103377_ReturnBeforeTaxes_D0731FidelityRealEstateIndexFundPRO08Member">Return Before Taxes</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000033639_C000103377_ReturnBeforeTaxes_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.2302</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnYear05
      contextRef="S000033639_C000103377_ReturnBeforeTaxes_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0635</rr:AverageAnnualReturnYear05>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000033639_C000103377_ReturnBeforeTaxes_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634367981_49"
      unitRef="pure">0.0993</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000033639_C000103377_AfterTaxesOnDistributions_D0731FidelityRealEstateIndexFundPRO08Member">Return After Taxes on Distributions</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000033639_C000103377_AfterTaxesOnDistributions_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.2153</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnYear05
      contextRef="S000033639_C000103377_AfterTaxesOnDistributions_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0503</rr:AverageAnnualReturnYear05>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000033639_C000103377_AfterTaxesOnDistributions_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634367981_53"
      unitRef="pure">0.0868</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000033639_C000103377_AfterTaxesOnDistributionsAndSales_D0731FidelityRealEstateIndexFundPRO08Member">Return After Taxes on Distributions and Sale of Fund Shares</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000033639_C000103377_AfterTaxesOnDistributionsAndSales_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.1406</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnYear05
      contextRef="S000033639_C000103377_AfterTaxesOnDistributionsAndSales_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0443</rr:AverageAnnualReturnYear05>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000033639_C000103377_AfterTaxesOnDistributionsAndSales_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634367981_57"
      unitRef="pure">0.0749</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000033639_IndexWA005_D0731FidelityRealEstateIndexFundPRO08Member">Dow Jones U.S. Select Real Estate Securities Index&#x2120;
</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000033639_IndexWA005_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.2310</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnYear05
      contextRef="S000033639_IndexWA005_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0639</rr:AverageAnnualReturnYear05>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000033639_IndexWA005_D0731FidelityRealEstateIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634367981_61"
      unitRef="pure">0.1001</rr:AverageAnnualReturnSinceInception>
    <rr:AnnualReturnInceptionDate contextRef="S000033639_D0731FidelityRealEstateIndexFundPRO08Member">2011-09-08</rr:AnnualReturnInceptionDate>
    <rr:RiskReturnHeading contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">Fund Summary
Fund:
Fidelity&#xae; SAI Real Estate Index Fund



</rr:RiskReturnHeading>
    <rr:ObjectiveHeading contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">Investment Objective

</rr:ObjectiveHeading>
    <rr:ObjectivePrimaryTextBlock contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">The fund seeks to provide investment results that correspond to the total return of equity Real Estate Investment Trusts (REITs) and other real estate-related investments.

</rr:ObjectivePrimaryTextBlock>
    <rr:ExpenseHeading contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">Fee Table

</rr:ExpenseHeading>
    <rr:ExpenseNarrativeTextBlock contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

</rr:ExpenseNarrativeTextBlock>
    <rr:ShareholderFeesCaption contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">Shareholder fees

</rr:ShareholderFeesCaption>
    <rr:ShareholderFeeOther
      contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">0</rr:ShareholderFeeOther>
    <rr:OperatingExpensesCaption contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">Annual Operating Expenses
(expenses that you pay each year as a % of the value of your investment)

</rr:OperatingExpensesCaption>
    <rr:ManagementFeesOverAssets
      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="6"
      unitRef="pure">0.00070</rr:ManagementFeesOverAssets>
    <rr:DistributionAndService12b1FeesOverAssets
      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0</rr:DistributionAndService12b1FeesOverAssets>
    <rr:OtherExpensesOverAssets
      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="6"
      unitRef="pure">0.00090</rr:OtherExpensesOverAssets>
    <rr:ExpensesOverAssets
      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="6"
      unitRef="pure">0.00160</rr:ExpensesOverAssets>
    <rr:FeeWaiverOrReimbursementOverAssets
      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="6"
      id="id_footnote_elem_634375518_71"
      unitRef="pure">-0.00090</rr:FeeWaiverOrReimbursementOverAssets>
    <rr:NetExpensesOverAssets
      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="6"
      unitRef="pure">0.00070</rr:NetExpensesOverAssets>
    <rr:FeeWaiverOrReimbursementOverAssetsDateOfTermination contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">November 30, 2021</rr:FeeWaiverOrReimbursementOverAssetsDateOfTermination>
    <rr:ExpenseExampleNarrativeTextBlock contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">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 your shareholder 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:

</rr:ExpenseExampleNarrativeTextBlock>
    <rr:ExpenseExampleYear01
      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">7</rr:ExpenseExampleYear01>
    <rr:ExpenseExampleYear03
      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">39</rr:ExpenseExampleYear03>
    <rr:ExpenseExampleYear05
      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">78</rr:ExpenseExampleYear05>
    <rr:ExpenseExampleYear10
      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">192</rr:ExpenseExampleYear10>
    <rr:PortfolioTurnoverHeading contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">Portfolio Turnover

</rr:PortfolioTurnoverHeading>
    <rr:PortfolioTurnoverTextBlock contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">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 82% of the average value of its portfolio.

</rr:PortfolioTurnoverTextBlock>
    <rr:PortfolioTurnoverRate
      contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.82</rr:PortfolioTurnoverRate>
    <rr:StrategyHeading contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">Principal Investment Strategies

</rr:StrategyHeading>
    <rr:StrategyNarrativeTextBlock contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">

Prior to December 1, 2020, normally investing at least 80% of assets in securities included in the Dow Jones U.S. Select Real Estate Securities Index&#x2120; (the Index).

Effective December 1, 2020, normally investing at least 80% of assets in securities included in the MSCI US IMI Real Estate 25/25 Index (the Index).



Lending securities to earn income for the fund.


</rr:StrategyNarrativeTextBlock>
    <rr:StrategyPortfolioConcentration contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">Prior to December 1, 2020, normally investing at least 80% of assets in securities included in the Dow Jones U.S. Select Real Estate Securities Index&#x2120; (the Index).

Effective December 1, 2020, normally investing at least 80% of assets in securities included in the MSCI US IMI Real Estate 25/25 Index (the Index).</rr:StrategyPortfolioConcentration>
    <rr:RiskHeading contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">Principal Investment Risks

</rr:RiskHeading>
    <rr:RiskNarrativeTextBlock contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">

Stock Market Volatility.&#160;
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.



Real Estate Industry Concentration.&#160;
Changes in real estate values or economic downturns can have a significant negative effect on issuers in the real estate industry. The value of securities of issuers in the real estate industry can be affected by changes in real estate values and rental income, property taxes, interest rates, tax and regulatory requirements, and the management skill and creditworthiness of the issuer.



Issuer-Specific Changes.&#160;
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.



Correlation to Index.&#160;
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.



Passive Management Risk.&#160;
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&#x92;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&#x92;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.



Securities Lending Risk.&#160;
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.


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. You could lose money by investing in the fund.

</rr:RiskNarrativeTextBlock>
    <rr:RiskNotInsuredDepositoryInstitution contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">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.</rr:RiskNotInsuredDepositoryInstitution>
    <rr:RiskLoseMoney contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">You could lose money by investing in the fund.</rr:RiskLoseMoney>
    <rr:BarChartAndPerformanceTableHeading contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">Performance

</rr:BarChartAndPerformanceTableHeading>
    <rr:PerformanceNarrativeTextBlock contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">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.

</rr:PerformanceNarrativeTextBlock>
    <rr:PerformanceInformationIllustratesVariabilityOfReturns contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">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.</rr:PerformanceInformationIllustratesVariabilityOfReturns>
    <rr:PerformancePastDoesNotIndicateFuture contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">Past performance (before and after taxes) is not an indication of future performance.</rr:PerformancePastDoesNotIndicateFuture>
    <rr:PerformanceAvailabilityWebSiteAddress contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">www.fidelity.com </rr:PerformanceAvailabilityWebSiteAddress>
    <rr:BarChartHeading contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">Year-by-Year Returns

</rr:BarChartHeading>
    <rr:HighestQuarterlyReturnLabel contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member">Highest Quarter Return</rr:HighestQuarterlyReturnLabel>
    <rr:BarChartHighestQuarterlyReturn
      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.1568</rr:BarChartHighestQuarterlyReturn>
    <rr:BarChartHighestQuarterlyReturnDate contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member">2019-03-31</rr:BarChartHighestQuarterlyReturnDate>
    <rr:LowestQuarterlyReturnLabel contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member">Lowest Quarter Return</rr:LowestQuarterlyReturnLabel>
    <rr:BarChartLowestQuarterlyReturn
      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">-0.0733</rr:BarChartLowestQuarterlyReturn>
    <rr:BarChartLowestQuarterlyReturnDate contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member">2018-03-31</rr:BarChartLowestQuarterlyReturnDate>
    <rr:YearToDateReturnLabel contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member">Year-to-Date Return</rr:YearToDateReturnLabel>
    <rr:BarChartYearToDateReturn
      contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">-0.2178</rr:BarChartYearToDateReturn>
    <rr:BarChartYearToDateReturnDate contextRef="S000051993_C000163539_D0731FidelitySAIRealEstateIndexFundPRO08Member">2020-06-30</rr:BarChartYearToDateReturnDate>
    <rr:PerformanceTableHeading contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">Average Annual Returns

</rr:PerformanceTableHeading>
    <rr:PerformanceTableNarrativeTextBlock contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">
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.

</rr:PerformanceTableNarrativeTextBlock>
    <rr:PerformanceTableUsesHighestFederalRate contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">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.</rr:PerformanceTableUsesHighestFederalRate>
    <rr:PerformanceTableNotRelevantToTaxDeferred contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">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).</rr:PerformanceTableNotRelevantToTaxDeferred>
    <rr:PerformanceTableExplanationAfterTaxHigher contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">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.</rr:PerformanceTableExplanationAfterTaxHigher>
    <rr:AverageAnnualReturnLabel contextRef="S000051993_C000163539_ReturnBeforeTaxes_D0731FidelitySAIRealEstateIndexFundPRO08Member">Return Before Taxes</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051993_C000163539_ReturnBeforeTaxes_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.2306</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051993_C000163539_ReturnBeforeTaxes_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634375799_108"
      unitRef="pure">0.0841</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000051993_C000163539_AfterTaxesOnDistributions_D0731FidelitySAIRealEstateIndexFundPRO08Member">Return After Taxes on Distributions</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051993_C000163539_AfterTaxesOnDistributions_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.2159</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051993_C000163539_AfterTaxesOnDistributions_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634375799_111"
      unitRef="pure">0.0709</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000051993_C000163539_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIRealEstateIndexFundPRO08Member">Return After Taxes on Distributions and Sale of Fund Shares</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051993_C000163539_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.1404</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051993_C000163539_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634375799_114"
      unitRef="pure">0.0604</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000051993_IndexWA005_D0731FidelitySAIRealEstateIndexFundPRO08Member">Dow Jones U.S. Select Real Estate Securities Index&#x2120;
</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051993_IndexWA005_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.2310</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051993_IndexWA005_D0731FidelitySAIRealEstateIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634375799_117"
      unitRef="pure">0.0845</rr:AverageAnnualReturnSinceInception>
    <rr:AnnualReturnInceptionDate contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">2016-02-02</rr:AnnualReturnInceptionDate>
    <rr:RiskReturnHeading contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Fund Summary
Fund:
Fidelity&#xae; SAI Small-Mid Cap 500 Index Fund



</rr:RiskReturnHeading>
    <rr:ObjectiveHeading contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Investment Objective

</rr:ObjectiveHeading>
    <rr:ObjectivePrimaryTextBlock contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">The fund seeks to provide investment results that correspond to the total return of stocks of small- to mid-capitalization United States companies.

</rr:ObjectivePrimaryTextBlock>
    <rr:ExpenseHeading contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Fee Table

</rr:ExpenseHeading>
    <rr:ExpenseNarrativeTextBlock contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

</rr:ExpenseNarrativeTextBlock>
    <rr:ShareholderFeesCaption contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Shareholder fees

</rr:ShareholderFeesCaption>
    <rr:ShareholderFeeOther
      contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="0"
      unitRef="usd">0</rr:ShareholderFeeOther>
    <rr:OperatingExpensesCaption contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Annual Operating Expenses
(expenses that you pay each year as a % of the value of your investment)

</rr:OperatingExpensesCaption>
    <rr:ManagementFeesOverAssets
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0011</rr:ManagementFeesOverAssets>
    <rr:DistributionAndService12b1FeesOverAssets
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0</rr:DistributionAndService12b1FeesOverAssets>
    <rr:OtherExpensesOverAssets
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0002</rr:OtherExpensesOverAssets>
    <rr:ExpensesOverAssets
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0013</rr:ExpensesOverAssets>
    <rr:FeeWaiverOrReimbursementOverAssets
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634434767_127"
      unitRef="pure">-0.0008</rr:FeeWaiverOrReimbursementOverAssets>
    <rr:NetExpensesOverAssets
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0005</rr:NetExpensesOverAssets>
    <rr:FeeWaiverOrReimbursementOverAssetsDateOfTermination contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">November 30, 2021</rr:FeeWaiverOrReimbursementOverAssetsDateOfTermination>
    <rr:ExpenseExampleNarrativeTextBlock contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">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 your shareholder 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:

</rr:ExpenseExampleNarrativeTextBlock>
    <rr:ExpenseExampleYear01
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="0"
      unitRef="usd">5</rr:ExpenseExampleYear01>
    <rr:ExpenseExampleYear03
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="0"
      unitRef="usd">31</rr:ExpenseExampleYear03>
    <rr:ExpenseExampleYear05
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="0"
      unitRef="usd">62</rr:ExpenseExampleYear05>
    <rr:ExpenseExampleYear10
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="0"
      unitRef="usd">156</rr:ExpenseExampleYear10>
    <rr:PortfolioTurnoverHeading contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Portfolio Turnover

</rr:PortfolioTurnoverHeading>
    <rr:PortfolioTurnoverTextBlock contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">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 79% of the average value of its portfolio.

</rr:PortfolioTurnoverTextBlock>
    <rr:PortfolioTurnoverRate
      contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.79</rr:PortfolioTurnoverRate>
    <rr:StrategyHeading contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Principal Investment Strategies

</rr:StrategyHeading>
    <rr:StrategyNarrativeTextBlock contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">
Normally investing at least 80% of assets in securities included in the Russell SMID 500&#x99; Index.


Lending securities to earn income for the fund.


</rr:StrategyNarrativeTextBlock>
    <rr:RiskHeading contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Principal Investment Risks

</rr:RiskHeading>
    <rr:RiskNarrativeTextBlock contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">

Stock Market Volatility.&#160;
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.



Issuer-Specific Changes.&#160;
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.



Correlation to Index.&#160;
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.



Small- and Mid-Cap Investing.&#160;
The value of securities of small to 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.



Passive Management Risk.&#160;
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&#x92;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&#x92;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.



Securities Lending Risk.&#160;
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.


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. You could lose money by investing in the fund.

</rr:RiskNarrativeTextBlock>
    <rr:RiskNotInsuredDepositoryInstitution contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">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.</rr:RiskNotInsuredDepositoryInstitution>
    <rr:RiskLoseMoney contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">You could lose money by investing in the fund.</rr:RiskLoseMoney>
    <rr:BarChartAndPerformanceTableHeading contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Performance

</rr:BarChartAndPerformanceTableHeading>
    <rr:PerformanceNarrativeTextBlock contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">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.

</rr:PerformanceNarrativeTextBlock>
    <rr:PerformanceInformationIllustratesVariabilityOfReturns contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">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.</rr:PerformanceInformationIllustratesVariabilityOfReturns>
    <rr:PerformancePastDoesNotIndicateFuture contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Past performance (before and after taxes) is not an indication of future performance.</rr:PerformancePastDoesNotIndicateFuture>
    <rr:PerformanceAvailabilityWebSiteAddress contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">www.fidelity.com</rr:PerformanceAvailabilityWebSiteAddress>
    <rr:BarChartHeading contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Year-by-Year Returns

</rr:BarChartHeading>
    <rr:HighestQuarterlyReturnLabel contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Highest Quarter Return</rr:HighestQuarterlyReturnLabel>
    <rr:BarChartHighestQuarterlyReturn
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.1678</rr:BarChartHighestQuarterlyReturn>
    <rr:BarChartHighestQuarterlyReturnDate contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">2019-03-31</rr:BarChartHighestQuarterlyReturnDate>
    <rr:LowestQuarterlyReturnLabel contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Lowest Quarter Return</rr:LowestQuarterlyReturnLabel>
    <rr:BarChartLowestQuarterlyReturn
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      unitRef="pure">-0.1708</rr:BarChartLowestQuarterlyReturn>
    <rr:BarChartLowestQuarterlyReturnDate contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">2018-12-31</rr:BarChartLowestQuarterlyReturnDate>
    <rr:YearToDateReturnLabel contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Year-to-Date Return</rr:YearToDateReturnLabel>
    <rr:BarChartYearToDateReturn
      contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      unitRef="pure">-0.0971</rr:BarChartYearToDateReturn>
    <rr:BarChartYearToDateReturnDate contextRef="S000050321_C000158877_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">2020-06-30</rr:BarChartYearToDateReturnDate>
    <rr:PerformanceTableHeading contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Average Annual Returns

</rr:PerformanceTableHeading>
    <rr:PerformanceTableNarrativeTextBlock contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">
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.

</rr:PerformanceTableNarrativeTextBlock>
    <rr:PerformanceTableUsesHighestFederalRate contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">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.</rr:PerformanceTableUsesHighestFederalRate>
    <rr:PerformanceTableNotRelevantToTaxDeferred contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">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).</rr:PerformanceTableNotRelevantToTaxDeferred>
    <rr:PerformanceTableExplanationAfterTaxHigher contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">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.</rr:PerformanceTableExplanationAfterTaxHigher>
    <rr:AverageAnnualReturnLabel contextRef="S000050321_C000158877_ReturnBeforeTaxes_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Return Before Taxes</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000050321_C000158877_ReturnBeforeTaxes_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.2953</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000050321_C000158877_ReturnBeforeTaxes_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634435052_164"
      unitRef="pure">0.0959</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000050321_C000158877_AfterTaxesOnDistributions_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Return After Taxes on Distributions</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000050321_C000158877_AfterTaxesOnDistributions_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.2798</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000050321_C000158877_AfterTaxesOnDistributions_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634435052_167"
      unitRef="pure">0.0857</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000050321_C000158877_AfterTaxesOnDistributionsAndSales_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Return After Taxes on Distributions and Sale of Fund Shares</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000050321_C000158877_AfterTaxesOnDistributionsAndSales_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.1837</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000050321_C000158877_AfterTaxesOnDistributionsAndSales_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634435052_170"
      unitRef="pure">0.0732</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000050321_IndexIX280_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">Russell SMID 500&#x99; Index
</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000050321_IndexIX280_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.2956</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000050321_IndexIX280_D0731FidelitySAISmallMidCap500IndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634435052_173"
      unitRef="pure">0.0968</rr:AverageAnnualReturnSinceInception>
    <rr:AnnualReturnInceptionDate contextRef="S000050321_D0731FidelitySAISmallMidCap500IndexFundPRO08Member">2015-08-12</rr:AnnualReturnInceptionDate>
    <rr:RiskReturnHeading contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Fund Summary
Fund:
Fidelity&#xae; SAI U.S. Large Cap Index Fund



</rr:RiskReturnHeading>
    <rr:ObjectiveHeading contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Investment Objective

</rr:ObjectiveHeading>
    <rr:ObjectivePrimaryTextBlock contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">The fund seeks to provide investment results that correspond to the total return of U.S. equities.

</rr:ObjectivePrimaryTextBlock>
    <rr:ExpenseHeading contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Fee Table

</rr:ExpenseHeading>
    <rr:ExpenseNarrativeTextBlock contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

</rr:ExpenseNarrativeTextBlock>
    <rr:ShareholderFeesCaption contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Shareholder fees

</rr:ShareholderFeesCaption>
    <rr:ShareholderFeeOther
      contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">0</rr:ShareholderFeeOther>
    <rr:OperatingExpensesCaption contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Annual Operating Expenses
(expenses that you pay each year as a % of the value of your investment)

</rr:OperatingExpensesCaption>
    <rr:ManagementFeesOverAssets
      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="6"
      unitRef="pure">0.00015</rr:ManagementFeesOverAssets>
    <rr:DistributionAndService12b1FeesOverAssets
      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0</rr:DistributionAndService12b1FeesOverAssets>
    <rr:OtherExpensesOverAssets
      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="6"
      unitRef="pure">0.00007</rr:OtherExpensesOverAssets>
    <rr:ExpensesOverAssets
      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="6"
      unitRef="pure">0.00022</rr:ExpensesOverAssets>
    <rr:FeeWaiverOrReimbursementOverAssets
      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="6"
      id="id_footnote_elem_634421726_182"
      unitRef="pure">-0.00004</rr:FeeWaiverOrReimbursementOverAssets>
    <rr:NetExpensesOverAssets
      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="6"
      unitRef="pure">0.00018</rr:NetExpensesOverAssets>
    <rr:FeeWaiverOrReimbursementOverAssetsDateOfTermination contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">November 30, 2021</rr:FeeWaiverOrReimbursementOverAssetsDateOfTermination>
    <rr:ExpenseExampleNarrativeTextBlock contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">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 your shareholder 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:

</rr:ExpenseExampleNarrativeTextBlock>
    <rr:ExpenseExampleYear01
      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">2</rr:ExpenseExampleYear01>
    <rr:ExpenseExampleYear03
      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">7</rr:ExpenseExampleYear03>
    <rr:ExpenseExampleYear05
      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">12</rr:ExpenseExampleYear05>
    <rr:ExpenseExampleYear10
      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">28</rr:ExpenseExampleYear10>
    <rr:PortfolioTurnoverHeading contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Portfolio Turnover

</rr:PortfolioTurnoverHeading>
    <rr:PortfolioTurnoverTextBlock contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">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 80% of the average value of its portfolio.

</rr:PortfolioTurnoverTextBlock>
    <rr:PortfolioTurnoverRate
      contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.80</rr:PortfolioTurnoverRate>
    <rr:StrategyHeading contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Principal Investment Strategies

</rr:StrategyHeading>
    <rr:StrategyNarrativeTextBlock contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">
Normally investing at least 80% of assets in common stocks of large capitalization U.S. companies included in the S&amp;P 500
&#xae; Index.


Lending securities to earn income for the fund.


</rr:StrategyNarrativeTextBlock>
    <rr:RiskHeading contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Principal Investment Risks

</rr:RiskHeading>
    <rr:RiskNarrativeTextBlock contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">

Stock Market Volatility.&#160;
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.



Issuer-Specific Changes.&#160;
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.



Correlation to Index.&#160;
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.



Passive Management Risk.&#160;
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&#x92;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&#x92;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.



Securities Lending Risk.&#160;
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.


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. You could lose money by investing in the fund.

</rr:RiskNarrativeTextBlock>
    <rr:RiskNotInsuredDepositoryInstitution contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">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.</rr:RiskNotInsuredDepositoryInstitution>
    <rr:RiskLoseMoney contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">You could lose money by investing in the fund.</rr:RiskLoseMoney>
    <rr:BarChartAndPerformanceTableHeading contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Performance

</rr:BarChartAndPerformanceTableHeading>
    <rr:PerformanceNarrativeTextBlock contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">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.

</rr:PerformanceNarrativeTextBlock>
    <rr:PerformanceInformationIllustratesVariabilityOfReturns contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">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.</rr:PerformanceInformationIllustratesVariabilityOfReturns>
    <rr:PerformancePastDoesNotIndicateFuture contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Past performance (before and after taxes) is not an indication of future performance.</rr:PerformancePastDoesNotIndicateFuture>
    <rr:PerformanceAvailabilityWebSiteAddress contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">www.fidelity.com</rr:PerformanceAvailabilityWebSiteAddress>
    <rr:BarChartHeading contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Year-by-Year Returns

</rr:BarChartHeading>
    <rr:HighestQuarterlyReturnLabel contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Highest Quarter Return</rr:HighestQuarterlyReturnLabel>
    <rr:BarChartHighestQuarterlyReturn
      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.1360</rr:BarChartHighestQuarterlyReturn>
    <rr:BarChartHighestQuarterlyReturnDate contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">2019-03-31</rr:BarChartHighestQuarterlyReturnDate>
    <rr:LowestQuarterlyReturnLabel contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Lowest Quarter Return</rr:LowestQuarterlyReturnLabel>
    <rr:BarChartLowestQuarterlyReturn
      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">-0.1352</rr:BarChartLowestQuarterlyReturn>
    <rr:BarChartLowestQuarterlyReturnDate contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">2018-12-31</rr:BarChartLowestQuarterlyReturnDate>
    <rr:YearToDateReturnLabel contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Year-to-Date Return</rr:YearToDateReturnLabel>
    <rr:BarChartYearToDateReturn
      contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">-0.0318</rr:BarChartYearToDateReturn>
    <rr:BarChartYearToDateReturnDate contextRef="S000051994_C000163540_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">2020-06-30</rr:BarChartYearToDateReturnDate>
    <rr:PerformanceTableHeading contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Average Annual Returns

</rr:PerformanceTableHeading>
    <rr:PerformanceTableNarrativeTextBlock contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">
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.

</rr:PerformanceTableNarrativeTextBlock>
    <rr:PerformanceTableUsesHighestFederalRate contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">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.</rr:PerformanceTableUsesHighestFederalRate>
    <rr:PerformanceTableNotRelevantToTaxDeferred contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">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).</rr:PerformanceTableNotRelevantToTaxDeferred>
    <rr:PerformanceTableExplanationAfterTaxHigher contextRef="S000051994_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">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.</rr:PerformanceTableExplanationAfterTaxHigher>
    <rr:AverageAnnualReturnLabel contextRef="S000051994_C000163540_ReturnBeforeTaxes_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Return Before Taxes</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051994_C000163540_ReturnBeforeTaxes_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.3153</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051994_C000163540_ReturnBeforeTaxes_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634421991_218"
      unitRef="pure">0.1685</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000051994_C000163540_AfterTaxesOnDistributions_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Return After Taxes on Distributions</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051994_C000163540_AfterTaxesOnDistributions_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.3097</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051994_C000163540_AfterTaxesOnDistributions_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634421991_221"
      unitRef="pure">0.1641</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000051994_C000163540_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">Return After Taxes on Distributions and Sale of Fund Shares</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051994_C000163540_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.1901</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051994_C000163540_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634421991_224"
      unitRef="pure">0.1339</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000051994_IndexSP001_D0731FidelitySAIUSLargeCapIndexFundPRO08Member">S&amp;P 500&#xae; Index
</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051994_IndexSP001_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.3149</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051994_IndexSP001_D0731FidelitySAIUSLargeCapIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634421991_227"
      unitRef="pure">0.1686</rr:AverageAnnualReturnSinceInception>
    <rr:AnnualReturnInceptionDate contextRef="S000051993_D0731FidelitySAIRealEstateIndexFundPRO08Member">2016-02-02</rr:AnnualReturnInceptionDate>
    <rr:RiskReturnHeading contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Fund Summary
Fund:
Fidelity&#xae; SAI U.S. Momentum Index Fund



</rr:RiskReturnHeading>
    <rr:ObjectiveHeading contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Investment Objective

</rr:ObjectiveHeading>
    <rr:ObjectivePrimaryTextBlock contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">The fund seeks to provide investment results that correspond to the total return of U.S. stocks with high price momentum.

</rr:ObjectivePrimaryTextBlock>
    <rr:ExpenseHeading contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Fee Table

</rr:ExpenseHeading>
    <rr:ExpenseNarrativeTextBlock contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

</rr:ExpenseNarrativeTextBlock>
    <rr:ShareholderFeesCaption contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Shareholder fees

</rr:ShareholderFeesCaption>
    <rr:ShareholderFeeOther
      contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="0"
      unitRef="usd">0</rr:ShareholderFeeOther>
    <rr:OperatingExpensesCaption contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Annual Operating Expenses
(expenses that you pay each year as a % of the value of your investment)

</rr:OperatingExpensesCaption>
    <rr:ManagementFeesOverAssets
      contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      unitRef="pure">0.0010</rr:ManagementFeesOverAssets>
    <rr:DistributionAndService12b1FeesOverAssets
      contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      unitRef="pure">0</rr:DistributionAndService12b1FeesOverAssets>
    <rr:OtherExpensesOverAssets
      contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      unitRef="pure">0.0001</rr:OtherExpensesOverAssets>
    <rr:ExpensesOverAssets
      contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      unitRef="pure">0.0011</rr:ExpensesOverAssets>
    <rr:ExpenseExampleNarrativeTextBlock contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">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 your shareholder 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:

</rr:ExpenseExampleNarrativeTextBlock>
    <rr:ExpenseExampleYear01
      contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="0"
      unitRef="usd">11</rr:ExpenseExampleYear01>
    <rr:ExpenseExampleYear03
      contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="0"
      unitRef="usd">35</rr:ExpenseExampleYear03>
    <rr:ExpenseExampleYear05
      contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="0"
      unitRef="usd">62</rr:ExpenseExampleYear05>
    <rr:ExpenseExampleYear10
      contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="0"
      unitRef="usd">141</rr:ExpenseExampleYear10>
    <rr:PortfolioTurnoverHeading contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Portfolio Turnover

</rr:PortfolioTurnoverHeading>
    <rr:PortfolioTurnoverTextBlock contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">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 163% of the average value of its portfolio.

</rr:PortfolioTurnoverTextBlock>
    <rr:PortfolioTurnoverRate
      contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      unitRef="pure">1.63</rr:PortfolioTurnoverRate>
    <rr:StrategyHeading contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Principal Investment Strategies

</rr:StrategyHeading>
    <rr:StrategyNarrativeTextBlock contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">
Normally investing at least 80% of assets in securities included in the MSCI USA Custom Momentum Composite Index. The MSCI USA Custom Momentum Composite Index is a customized version of the MSCI USA Momentum Index, which is designed to reflect the performance of an equity momentum strategy by emphasizing stocks with relatively higher price momentum.


Lending securities to earn income for the fund.


</rr:StrategyNarrativeTextBlock>
    <rr:RiskHeading contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Principal Investment Risks

</rr:RiskHeading>
    <rr:RiskNarrativeTextBlock contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">

Stock Market Volatility.&#160;
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.



Issuer-Specific Changes.&#160;
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.



Correlation to Index.&#160;
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.



Passive Management Risk.&#160;
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&#x92;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&#x92;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.



Momentum Securities Risk.&#160;
Although the fund&#x92;s underlying index uses a rules-based proprietary index methodology that is designed to identify stocks that exhibit positive momentum signals, there is no guarantee that this methodology will be successful. Stocks that previously exhibited high momentum characteristics may not experience positive momentum or may experience more volatility than the market as a whole.



High Portfolio Turnover.&#160;
High portfolio turnover (more than 100%) may result in increased transaction costs and potentially higher capital gains or losses. The effects of higher than normal portfolio turnover may adversely affect the fund's performance.



Securities Lending Risk.&#160;
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.


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. You could lose money by investing in the fund.

</rr:RiskNarrativeTextBlock>
    <rr:RiskNotInsuredDepositoryInstitution contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">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.</rr:RiskNotInsuredDepositoryInstitution>
    <rr:RiskLoseMoney contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">You could lose money by investing in the fund.</rr:RiskLoseMoney>
    <rr:BarChartAndPerformanceTableHeading contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Performance

</rr:BarChartAndPerformanceTableHeading>
    <rr:PerformanceNarrativeTextBlock contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">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.

</rr:PerformanceNarrativeTextBlock>
    <rr:PerformanceInformationIllustratesVariabilityOfReturns contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">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.</rr:PerformanceInformationIllustratesVariabilityOfReturns>
    <rr:PerformancePastDoesNotIndicateFuture contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Past performance (before and after taxes) is not an indication of future performance.</rr:PerformancePastDoesNotIndicateFuture>
    <rr:PerformanceAvailabilityWebSiteAddress contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">www.fidelity.com</rr:PerformanceAvailabilityWebSiteAddress>
    <rr:BarChartHeading contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Year-by-Year Returns

</rr:BarChartHeading>
    <rr:HighestQuarterlyReturnLabel contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Highest Quarter Return</rr:HighestQuarterlyReturnLabel>
    <rr:BarChartHighestQuarterlyReturn
      contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      unitRef="pure">0.1155</rr:BarChartHighestQuarterlyReturn>
    <rr:BarChartHighestQuarterlyReturnDate contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member">2019-03-31</rr:BarChartHighestQuarterlyReturnDate>
    <rr:LowestQuarterlyReturnLabel contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Lowest Quarter Return</rr:LowestQuarterlyReturnLabel>
    <rr:BarChartLowestQuarterlyReturn
      contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      unitRef="pure">-0.1528</rr:BarChartLowestQuarterlyReturn>
    <rr:BarChartLowestQuarterlyReturnDate contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member">2018-12-31</rr:BarChartLowestQuarterlyReturnDate>
    <rr:YearToDateReturnLabel contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Year-to-Date Return</rr:YearToDateReturnLabel>
    <rr:BarChartYearToDateReturn
      contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      unitRef="pure">0.0482</rr:BarChartYearToDateReturn>
    <rr:BarChartYearToDateReturnDate contextRef="S000056275_C000177148_D0731FidelitySAIUSMomentumIndexFundPRO07Member">2020-06-30</rr:BarChartYearToDateReturnDate>
    <rr:PerformanceTableHeading contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Average Annual Returns

</rr:PerformanceTableHeading>
    <rr:PerformanceTableNarrativeTextBlock contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">
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.

</rr:PerformanceTableNarrativeTextBlock>
    <rr:PerformanceTableUsesHighestFederalRate contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">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.</rr:PerformanceTableUsesHighestFederalRate>
    <rr:PerformanceTableNotRelevantToTaxDeferred contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">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).</rr:PerformanceTableNotRelevantToTaxDeferred>
    <rr:PerformanceTableExplanationAfterTaxHigher contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">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.</rr:PerformanceTableExplanationAfterTaxHigher>
    <rr:AverageAnnualReturnLabel contextRef="S000056275_C000177148_ReturnBeforeTaxes_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Return Before Taxes</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000056275_C000177148_ReturnBeforeTaxes_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      unitRef="pure">0.2416</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000056275_C000177148_ReturnBeforeTaxes_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      id="id_footnote_elem_634437001_268"
      unitRef="pure">0.1512</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000056275_C000177148_AfterTaxesOnDistributions_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Return After Taxes on Distributions</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000056275_C000177148_AfterTaxesOnDistributions_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      unitRef="pure">0.2353</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000056275_C000177148_AfterTaxesOnDistributions_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      id="id_footnote_elem_634437001_271"
      unitRef="pure">0.1436</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000056275_C000177148_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIUSMomentumIndexFundPRO07Member">Return After Taxes on Distributions and Sale of Fund Shares</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000056275_C000177148_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      unitRef="pure">0.1472</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000056275_C000177148_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      id="id_footnote_elem_634437001_274"
      unitRef="pure">0.1166</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000056275_IndexIXZE4_D0731FidelitySAIUSMomentumIndexFundPRO07Member">MSCI USA Custom Momentum Composite Index
</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000056275_IndexIXZE4_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      unitRef="pure">0.2430</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000056275_IndexIXZE4_D0731FidelitySAIUSMomentumIndexFundPRO07Member"
      decimals="4"
      id="id_footnote_elem_634437001_277"
      unitRef="pure">0.1528</rr:AverageAnnualReturnSinceInception>
    <rr:AnnualReturnInceptionDate contextRef="S000056275_D0731FidelitySAIUSMomentumIndexFundPRO07Member">2017-02-09</rr:AnnualReturnInceptionDate>
    <rr:RiskReturnHeading contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">Fund Summary
Fund:
Fidelity&#xae; SAI U.S. Quality Index Fund



</rr:RiskReturnHeading>
    <rr:ObjectiveHeading contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">Investment Objective

</rr:ObjectiveHeading>
    <rr:ObjectivePrimaryTextBlock contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">The fund seeks to provide investment results that correspond to the total return of stocks of quality growth United States companies.

</rr:ObjectivePrimaryTextBlock>
    <rr:ExpenseHeading contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">Fee Table

</rr:ExpenseHeading>
    <rr:ExpenseNarrativeTextBlock contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

</rr:ExpenseNarrativeTextBlock>
    <rr:ShareholderFeesCaption contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">Shareholder fees

</rr:ShareholderFeesCaption>
    <rr:ShareholderFeeOther
      contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">0</rr:ShareholderFeeOther>
    <rr:OperatingExpensesCaption contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">Annual Operating Expenses
(expenses that you pay each year as a % of the value of your investment)

</rr:OperatingExpensesCaption>
    <rr:ManagementFeesOverAssets
      contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0010</rr:ManagementFeesOverAssets>
    <rr:DistributionAndService12b1FeesOverAssets
      contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0</rr:DistributionAndService12b1FeesOverAssets>
    <rr:OtherExpensesOverAssets
      contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0001</rr:OtherExpensesOverAssets>
    <rr:ExpensesOverAssets
      contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0011</rr:ExpensesOverAssets>
    <rr:ExpenseExampleNarrativeTextBlock contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">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 your shareholder 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:

</rr:ExpenseExampleNarrativeTextBlock>
    <rr:ExpenseExampleYear01
      contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">11</rr:ExpenseExampleYear01>
    <rr:ExpenseExampleYear03
      contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">35</rr:ExpenseExampleYear03>
    <rr:ExpenseExampleYear05
      contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">62</rr:ExpenseExampleYear05>
    <rr:ExpenseExampleYear10
      contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="0"
      unitRef="usd">141</rr:ExpenseExampleYear10>
    <rr:PortfolioTurnoverHeading contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">Portfolio Turnover

</rr:PortfolioTurnoverHeading>
    <rr:PortfolioTurnoverTextBlock contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">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 60% of the average value of its portfolio.

</rr:PortfolioTurnoverTextBlock>
    <rr:PortfolioTurnoverRate
      contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.60</rr:PortfolioTurnoverRate>
    <rr:StrategyHeading contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">Principal Investment Strategies

</rr:StrategyHeading>
    <rr:StrategyNarrativeTextBlock contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">
Normally investing at least 80% of assets in equity securities included in the Fidelity U.S. Quality Focus Index&#x2120;. The Fidelity U.S. Quality Focus Index&#x2120; seeks to capture the performance of a broad range of U.S. equities that have attractive quality scores. Quality scores for non-financial companies and non-real estate investment trusts are based on ten variables: high free cash flow margin, return on invested capital, gross profit margin, and return on equity; stable earnings growth, return on assets, free cash flow, and accruals; and low financial leverage and accruals. Financials and Real Estate Investment Trusts (REITs) are ranked using a composite score based on four measures of quality: high return on equity, stable earnings growth and return on equity, and low financial leverage.


Using statistical sampling techniques taking into account such factors as capitalization, industry exposures, dividend yield, price/earnings (P/E) ratio, price/book (P/B) ratio, and earnings growth to attempt to replicate the returns of the Fidelity U.S. Quality Focus Index&#x2120;.


Lending securities to earn income for the fund.


</rr:StrategyNarrativeTextBlock>
    <rr:RiskHeading contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">Principal Investment Risks

</rr:RiskHeading>
    <rr:RiskNarrativeTextBlock contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">

Quality Stocks.&#160;
Although the fund&#x92;s underlying index uses a rules-based proprietary index methodology that is designed to identify stocks with a higher quality profile than the broader market, there is no guarantee that this methodology will be successful or that the past performance of these stocks will continue. Companies that issue these stocks may experience lower than expected returns or may experience negative growth, as well as increased leverage, resulting in lower than expected or negative returns.



Stock Market Volatility.&#160;
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.



Issuer-Specific Changes.&#160;
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.



Correlation to Index.&#160;
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.



Passive Management Risk.&#160;
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&#x92;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&#x92;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.



"Growth" Investing.&#160;
"Growth" stocks can perform differently from the market as a whole and other types of stocks and can be more volatile than other types of stocks.



Securities Lending Risk.&#160;
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.


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. You could lose money by investing in the fund.

</rr:RiskNarrativeTextBlock>
    <rr:RiskNotInsuredDepositoryInstitution contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">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.</rr:RiskNotInsuredDepositoryInstitution>
    <rr:RiskLoseMoney contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">You could lose money by investing in the fund.</rr:RiskLoseMoney>
    <rr:BarChartAndPerformanceTableHeading contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">Performance

</rr:BarChartAndPerformanceTableHeading>
    <rr:PerformanceNarrativeTextBlock contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">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.

Prior to March 18, 2019, the fund operated under certain different investment policies and compared its performance to a different index. The fund's historical performance may not represent its current investment policies.

Visit
www.fidelity.com for more recent performance information.

</rr:PerformanceNarrativeTextBlock>
    <rr:PerformanceInformationIllustratesVariabilityOfReturns contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">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.</rr:PerformanceInformationIllustratesVariabilityOfReturns>
    <rr:PerformancePastDoesNotIndicateFuture contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">Past performance (before and after taxes) is not an indication of future performance.</rr:PerformancePastDoesNotIndicateFuture>
    <rr:PerformanceAvailabilityWebSiteAddress contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">www.fidelity.com</rr:PerformanceAvailabilityWebSiteAddress>
    <rr:BarChartHeading contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">Year-by-Year Returns

</rr:BarChartHeading>
    <rr:HighestQuarterlyReturnLabel contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member">Highest Quarter Return</rr:HighestQuarterlyReturnLabel>
    <rr:BarChartHighestQuarterlyReturn
      contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.1621</rr:BarChartHighestQuarterlyReturn>
    <rr:BarChartHighestQuarterlyReturnDate contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member">2019-03-31</rr:BarChartHighestQuarterlyReturnDate>
    <rr:LowestQuarterlyReturnLabel contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member">Lowest Quarter Return</rr:LowestQuarterlyReturnLabel>
    <rr:BarChartLowestQuarterlyReturn
      contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">-0.1380</rr:BarChartLowestQuarterlyReturn>
    <rr:BarChartLowestQuarterlyReturnDate contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member">2018-12-31</rr:BarChartLowestQuarterlyReturnDate>
    <rr:YearToDateReturnLabel contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member">Year-to-Date Return</rr:YearToDateReturnLabel>
    <rr:BarChartYearToDateReturn
      contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.0279</rr:BarChartYearToDateReturn>
    <rr:BarChartYearToDateReturnDate contextRef="S000051137_C000161034_D0731FidelitySAIUSQualityIndexFundPRO08Member">2020-06-30</rr:BarChartYearToDateReturnDate>
    <rr:PerformanceTableHeading contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">Average Annual Returns

</rr:PerformanceTableHeading>
    <rr:PerformanceTableNarrativeTextBlock contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">
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.

</rr:PerformanceTableNarrativeTextBlock>
    <rr:PerformanceTableUsesHighestFederalRate contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">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.</rr:PerformanceTableUsesHighestFederalRate>
    <rr:PerformanceTableNotRelevantToTaxDeferred contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">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).</rr:PerformanceTableNotRelevantToTaxDeferred>
    <rr:PerformanceTableExplanationAfterTaxHigher contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">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.</rr:PerformanceTableExplanationAfterTaxHigher>
    <rr:AverageAnnualReturnLabel contextRef="S000051137_C000161034_ReturnBeforeTaxes_D0731FidelitySAIUSQualityIndexFundPRO08Member">Return Before Taxes</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051137_C000161034_ReturnBeforeTaxes_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.3407</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051137_C000161034_ReturnBeforeTaxes_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634439042_320"
      unitRef="pure">0.1534</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000051137_C000161034_AfterTaxesOnDistributions_D0731FidelitySAIUSQualityIndexFundPRO08Member">Return After Taxes on Distributions</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051137_C000161034_AfterTaxesOnDistributions_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.2958</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051137_C000161034_AfterTaxesOnDistributions_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634439042_323"
      unitRef="pure">0.1381</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000051137_C000161034_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIUSQualityIndexFundPRO08Member">Return After Taxes on Distributions and Sale of Fund Shares</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051137_C000161034_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.2222</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051137_C000161034_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634439042_326"
      unitRef="pure">0.1191</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000051137_IndexIXYOZ_D0731FidelitySAIUSQualityIndexFundPRO08Member">Fidelity U.S. Quality Focus Index&#x2120;
</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051137_IndexIXYOZ_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.3088</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051137_IndexIXYOZ_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      id="id_footnote_elem_634439042_329"
      unitRef="pure"
      xsi:nil="true"/>
    <rr:AverageAnnualReturnLabel contextRef="S000051137_IndexIXYXM_D0731FidelitySAIUSQualityIndexFundPRO08Member">Fidelity SAI U.S. Quality Index Fund Linked Index&#x2120;
</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051137_IndexIXYXM_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.3403</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051137_IndexIXYXM_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634439042_332"
      unitRef="pure">0.1547</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000051137_IndexIX201_D0731FidelitySAIUSQualityIndexFundPRO08Member">MSCI USA Quality Index
</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000051137_IndexIX201_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      unitRef="pure">0.3911</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000051137_IndexIX201_D0731FidelitySAIUSQualityIndexFundPRO08Member"
      decimals="4"
      id="id_footnote_elem_634439042_335"
      unitRef="pure">0.1649</rr:AverageAnnualReturnSinceInception>
    <rr:AnnualReturnInceptionDate contextRef="S000051137_D0731FidelitySAIUSQualityIndexFundPRO08Member">2015-10-08</rr:AnnualReturnInceptionDate>
    <rr:RiskReturnHeading contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">Fund Summary
Fund:
Fidelity&#xae; SAI U.S. Value Index Fund



</rr:RiskReturnHeading>
    <rr:ObjectiveHeading contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">Investment Objective

</rr:ObjectiveHeading>
    <rr:ObjectivePrimaryTextBlock contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">The fund seeks to provide investment results that correspond to the total return of U.S. stocks with attractive valuations.

</rr:ObjectivePrimaryTextBlock>
    <rr:ExpenseHeading contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">Fee Table

</rr:ExpenseHeading>
    <rr:ExpenseNarrativeTextBlock contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

</rr:ExpenseNarrativeTextBlock>
    <rr:ShareholderFeesCaption contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">Shareholder fees

</rr:ShareholderFeesCaption>
    <rr:ShareholderFeeOther
      contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="0"
      unitRef="usd">0</rr:ShareholderFeeOther>
    <rr:OperatingExpensesCaption contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">Annual Operating Expenses
(expenses that you pay each year as a % of the value of your investment)

</rr:OperatingExpensesCaption>
    <rr:ManagementFeesOverAssets
      contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      unitRef="pure">0.0010</rr:ManagementFeesOverAssets>
    <rr:DistributionAndService12b1FeesOverAssets
      contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      unitRef="pure">0</rr:DistributionAndService12b1FeesOverAssets>
    <rr:OtherExpensesOverAssets
      contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      unitRef="pure">0.0001</rr:OtherExpensesOverAssets>
    <rr:ExpensesOverAssets
      contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      unitRef="pure">0.0011</rr:ExpensesOverAssets>
    <rr:ExpenseExampleNarrativeTextBlock contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">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 your shareholder 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:

</rr:ExpenseExampleNarrativeTextBlock>
    <rr:ExpenseExampleYear01
      contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="0"
      unitRef="usd">11</rr:ExpenseExampleYear01>
    <rr:ExpenseExampleYear03
      contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="0"
      unitRef="usd">35</rr:ExpenseExampleYear03>
    <rr:ExpenseExampleYear05
      contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="0"
      unitRef="usd">62</rr:ExpenseExampleYear05>
    <rr:ExpenseExampleYear10
      contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="0"
      unitRef="usd">141</rr:ExpenseExampleYear10>
    <rr:PortfolioTurnoverHeading contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">Portfolio Turnover

</rr:PortfolioTurnoverHeading>
    <rr:PortfolioTurnoverTextBlock contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">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 82% of the average value of its portfolio.

</rr:PortfolioTurnoverTextBlock>
    <rr:PortfolioTurnoverRate
      contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      unitRef="pure">0.82</rr:PortfolioTurnoverRate>
    <rr:StrategyHeading contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">Principal Investment Strategies

</rr:StrategyHeading>
    <rr:StrategyNarrativeTextBlock contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">
Normally investing at least 80% of assets in securities included in the Fidelity U.S. Value Focus Index&#x2120;.


Using statistical sampling techniques based on such factors as capitalization, industry exposures, dividend yield, price/earnings (P/E) ratio, price/book (P/B) ratio, and earnings growth to attempt to replicate the returns of the Fidelity U.S. Value Focus Index&#x2120;.


Lending securities to earn income for the fund.


</rr:StrategyNarrativeTextBlock>
    <rr:RiskHeading contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">Principal Investment Risks

</rr:RiskHeading>
    <rr:RiskNarrativeTextBlock contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">

Stock Market Volatility.&#160;
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.



Issuer-Specific Changes.&#160;
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.



Correlation to Index.&#160;
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.



Passive Management Risk.&#160;
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 or group of industries.



"Value" Investing.&#160;
Although the fund&#x92;s underlying index uses a rules-based proprietary index methodology that is designed to identify stocks with attractive valuations, there is no guarantee that this methodology will be successful or that these stocks will continue to be good &#x93;values.&#x94; &#x93;Value&#x94; stocks can perform differently from the market as a whole and other types of stocks and can continue to be undervalued by the market for long periods of time.



Securities Lending Risk.&#160;
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.


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. You could lose money by investing in the fund.

</rr:RiskNarrativeTextBlock>
    <rr:RiskNotInsuredDepositoryInstitution contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">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.</rr:RiskNotInsuredDepositoryInstitution>
    <rr:RiskLoseMoney contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">You could lose money by investing in the fund.</rr:RiskLoseMoney>
    <rr:BarChartAndPerformanceTableHeading contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">Performance

</rr:BarChartAndPerformanceTableHeading>
    <rr:PerformanceNarrativeTextBlock contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">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.

</rr:PerformanceNarrativeTextBlock>
    <rr:PerformanceInformationIllustratesVariabilityOfReturns contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">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.</rr:PerformanceInformationIllustratesVariabilityOfReturns>
    <rr:PerformancePastDoesNotIndicateFuture contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">Past performance (before and after taxes) is not an indication of future performance.</rr:PerformancePastDoesNotIndicateFuture>
    <rr:PerformanceAvailabilityWebSiteAddress contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">www.fidelity.com</rr:PerformanceAvailabilityWebSiteAddress>
    <rr:BarChartHeading contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">Year-by-Year Returns

</rr:BarChartHeading>
    <rr:HighestQuarterlyReturnLabel contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member">Highest Quarter Return</rr:HighestQuarterlyReturnLabel>
    <rr:BarChartHighestQuarterlyReturn
      contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      unitRef="pure">0.1256</rr:BarChartHighestQuarterlyReturn>
    <rr:BarChartHighestQuarterlyReturnDate contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member">2019-03-31</rr:BarChartHighestQuarterlyReturnDate>
    <rr:LowestQuarterlyReturnLabel contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member">Lowest Quarter Return</rr:LowestQuarterlyReturnLabel>
    <rr:BarChartLowestQuarterlyReturn
      contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      unitRef="pure">-0.1498</rr:BarChartLowestQuarterlyReturn>
    <rr:BarChartLowestQuarterlyReturnDate contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member">2018-12-31</rr:BarChartLowestQuarterlyReturnDate>
    <rr:YearToDateReturnLabel contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member">Year-to-Date Return</rr:YearToDateReturnLabel>
    <rr:BarChartYearToDateReturn
      contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      unitRef="pure">-0.1911</rr:BarChartYearToDateReturn>
    <rr:BarChartYearToDateReturnDate contextRef="S000059763_C000195574_D0731FidelitySAIUSValueIndexFundPRO06Member">2020-06-30</rr:BarChartYearToDateReturnDate>
    <rr:PerformanceTableHeading contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">Average Annual Returns

</rr:PerformanceTableHeading>
    <rr:PerformanceTableNarrativeTextBlock contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">
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.

</rr:PerformanceTableNarrativeTextBlock>
    <rr:PerformanceTableUsesHighestFederalRate contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">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.</rr:PerformanceTableUsesHighestFederalRate>
    <rr:PerformanceTableNotRelevantToTaxDeferred contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">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).</rr:PerformanceTableNotRelevantToTaxDeferred>
    <rr:PerformanceTableExplanationAfterTaxHigher contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">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.</rr:PerformanceTableExplanationAfterTaxHigher>
    <rr:AverageAnnualReturnLabel contextRef="S000059763_C000195574_ReturnBeforeTaxes_D0731FidelitySAIUSValueIndexFundPRO06Member">Return Before Taxes</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000059763_C000195574_ReturnBeforeTaxes_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      unitRef="pure">0.2909</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000059763_C000195574_ReturnBeforeTaxes_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      id="id_footnote_elem_634441210_377"
      unitRef="pure">0.0717</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000059763_C000195574_AfterTaxesOnDistributions_D0731FidelitySAIUSValueIndexFundPRO06Member">Return After Taxes on Distributions</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000059763_C000195574_AfterTaxesOnDistributions_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      unitRef="pure">0.2832</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000059763_C000195574_AfterTaxesOnDistributions_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      id="id_footnote_elem_634441210_380"
      unitRef="pure">0.0628</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000059763_C000195574_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIUSValueIndexFundPRO06Member">Return After Taxes on Distributions and Sale of Fund Shares</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000059763_C000195574_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      unitRef="pure">0.1770</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000059763_C000195574_AfterTaxesOnDistributionsAndSales_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      id="id_footnote_elem_634441210_383"
      unitRef="pure">0.0529</rr:AverageAnnualReturnSinceInception>
    <rr:AverageAnnualReturnLabel contextRef="S000059763_IndexIXYEF_D0731FidelitySAIUSValueIndexFundPRO06Member">Fidelity U.S. Value Focus Index&#x2120;
</rr:AverageAnnualReturnLabel>
    <rr:AverageAnnualReturnYear01
      contextRef="S000059763_IndexIXYEF_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      unitRef="pure">0.2920</rr:AverageAnnualReturnYear01>
    <rr:AverageAnnualReturnSinceInception
      contextRef="S000059763_IndexIXYEF_D0731FidelitySAIUSValueIndexFundPRO06Member"
      decimals="4"
      id="id_footnote_elem_634441210_386"
      unitRef="pure">0.0721</rr:AverageAnnualReturnSinceInception>
    <rr:AnnualReturnInceptionDate contextRef="S000059763_D0731FidelitySAIUSValueIndexFundPRO06Member">2017-12-19</rr:AnnualReturnInceptionDate>
    <link:footnoteLink
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        <link:loc
          xlink:href="#id_footnote_elem_634367981_49"
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        <link:footnote id="footnote_634367980" xlink:label="footnote_634367980" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:p style="font: 11px Arial, Helvetica, sans-serif;">
<xhtml:sup>(a)</xhtml:sup>
<xhtml:i>From
September 8, 2011
</xhtml:i>
</xhtml:p>

</link:footnote>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
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        <link:loc
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        <link:loc
          xlink:href="#id_footnote_elem_634375518_71"
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        <link:footnote id="footnote_629351428" xlink:label="footnote_629351428" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:p style="font: 11px Arial, Helvetica, sans-serif;">
<xhtml:sup>(a)</xhtml:sup>
<xhtml:i>Fidelity Management &amp; Research Company LLC (FMR) has contractually agreed to reimburse the fund to the extent that total operating expenses (excluding interest, certain taxes, fees and expenses of the Independent Trustees, proxy and shareholder meeting expenses, extraordinary expenses, and acquired fund fees and expenses, if any, as well as non-operating expenses such as brokerage commissions and fees and expenses associated with the fund's securities lending program, if applicable), as a percentage of its average net assets, exceed 0.07% (the Expense Cap). If at any time during the current fiscal year expenses for the fund fall below the Expense Cap, FMR reserves the right to recoup through the end of the fiscal year any expenses that were reimbursed during the current fiscal year up to, but not in excess of, the Expense Cap. This arrangement will remain in effect through
November 30, 2021. FMR may not terminate this arrangement before the expiration date without the approval of the Board of Trustees and may extend it in its discretion after that date.</xhtml:i>
</xhtml:p>

</link:footnote>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="id_footnote_elem_634375518_71"
          xlink:to="footnote_629351428"
          xlink:type="arc"/>
        <link:loc
          xlink:href="#id_footnote_elem_634375799_108"
          xlink:label="id_footnote_elem_634375799_108"
          xlink:type="locator"/>
        <link:footnote id="footnote_634370616" xlink:label="footnote_634370616" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:p style="font: 11px Arial, Helvetica, sans-serif;">
<xhtml:sup>(a)</xhtml:sup>
<xhtml:i>From
February 2, 2016
</xhtml:i>
</xhtml:p>

</link:footnote>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="id_footnote_elem_634375799_108"
          xlink:to="footnote_634370616"
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        <link:loc
          xlink:href="#id_footnote_elem_634375799_111"
          xlink:label="id_footnote_elem_634375799_111"
          xlink:type="locator"/>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="id_footnote_elem_634375799_111"
          xlink:to="footnote_634370616"
          xlink:type="arc"/>
        <link:loc
          xlink:href="#id_footnote_elem_634375799_114"
          xlink:label="id_footnote_elem_634375799_114"
          xlink:type="locator"/>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="id_footnote_elem_634375799_114"
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        <link:loc
          xlink:href="#id_footnote_elem_634375799_117"
          xlink:label="id_footnote_elem_634375799_117"
          xlink:type="locator"/>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="id_footnote_elem_634375799_117"
          xlink:to="footnote_634370616"
          xlink:type="arc"/>
        <link:loc
          xlink:href="#id_footnote_elem_634434767_127"
          xlink:label="id_footnote_elem_634434767_127"
          xlink:type="locator"/>
        <link:footnote id="footnote_629968097" xlink:label="footnote_629968097" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:p style="font: 11px Arial, Helvetica, sans-serif;">
<xhtml:sup>(a)</xhtml:sup>
<xhtml:i>Fidelity Management &amp; Research Company LLC (FMR) has contractually agreed to reimburse the fund to the extent that the management fee total operating expenses (excluding interest, certain taxes, fees and expenses of the Independent Trustees, proxy and shareholder meeting expenses, extraordinary expenses,and acquired fund fees and expenses, if any, as well as non-operating expenses such as brokerage commissions and fees and expenses associated with the fund's securities lending program, if applicable), as a percentage of its average net assets, exceed 0.05% (the Expense Cap). If at any time during the current fiscal year expenses for the fund fall below the Expense Cap, FMR reserves the right to recoup through the end of the fiscal year any expenses that were reimbursed during the current fiscal year up to, but not in excess of, the Expense Cap. This arrangement will remain in effect through
November 30, 2021. FMR may not terminate this arrangement before the expiration date without the approval of the Board of Trustees and may extend it in its discretion after that date.</xhtml:i>
</xhtml:p>

</link:footnote>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="id_footnote_elem_634434767_127"
          xlink:to="footnote_629968097"
          xlink:type="arc"/>
        <link:loc
          xlink:href="#id_footnote_elem_634435052_164"
          xlink:label="id_footnote_elem_634435052_164"
          xlink:type="locator"/>
        <link:footnote id="footnote_634435051" xlink:label="footnote_634435051" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:p style="font: 11px Arial, Helvetica, sans-serif;">
<xhtml:sup>(a)</xhtml:sup>
<xhtml:i>From
August 12, 2015
</xhtml:i>
</xhtml:p>

</link:footnote>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
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          xlink:type="arc"/>
        <link:loc
          xlink:href="#id_footnote_elem_634435052_167"
          xlink:label="id_footnote_elem_634435052_167"
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        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="id_footnote_elem_634435052_167"
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        <link:loc
          xlink:href="#id_footnote_elem_634435052_170"
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          xlink:type="locator"/>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="id_footnote_elem_634435052_170"
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        <link:loc
          xlink:href="#id_footnote_elem_634435052_173"
          xlink:label="id_footnote_elem_634435052_173"
          xlink:type="locator"/>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="id_footnote_elem_634435052_173"
          xlink:to="footnote_634435051"
          xlink:type="arc"/>
        <link:loc
          xlink:href="#id_footnote_elem_634421726_182"
          xlink:label="id_footnote_elem_634421726_182"
          xlink:type="locator"/>
        <link:footnote id="footnote_630782095" xlink:label="footnote_630782095" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:p style="font: 11px Arial, Helvetica, sans-serif;">
<xhtml:sup>(a)</xhtml:sup>
<xhtml:i>Fidelity Management &amp; Research Company LLC (FMR) has contractually agreed to reimburse the fund to the extent that total operating expenses (excluding interest, certain taxes, fees and expenses of the Independent Trustees, proxy and shareholder meeting expenses, extraordinary expenses, and acquired fund fees and expenses, if any, as well as non-operating expenses such as brokerage commissions and fees and expenses associated with the fund's securities lending program, if applicable), as a percentage of its average net assets, exceed 0.015% (the Expense Cap). If at any time during the current fiscal year expenses for the fund fall below the Expense Cap, FMR reserves the right to recoup through the end of the fiscal year any expenses that were reimbursed during the current fiscal year up to, but not in excess of, the Expense Cap. This arrangement will remain in effect through
November 30, 2021. FMR may not terminate this arrangement before the expiration date without the approval of the Board of Trustees and may extend it in its discretion after that date.</xhtml:i>
</xhtml:p>

</link:footnote>
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        <link:loc
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        <link:loc
          xlink:href="#id_footnote_elem_634421991_221"
          xlink:label="id_footnote_elem_634421991_221"
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        <link:footnoteArc
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          xlink:from="id_footnote_elem_634421991_221"
          xlink:to="footnote_634370616"
          xlink:type="arc"/>
        <link:loc
          xlink:href="#id_footnote_elem_634421991_224"
          xlink:label="id_footnote_elem_634421991_224"
          xlink:type="locator"/>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="id_footnote_elem_634421991_224"
          xlink:to="footnote_634370616"
          xlink:type="arc"/>
        <link:loc
          xlink:href="#id_footnote_elem_634421991_227"
          xlink:label="id_footnote_elem_634421991_227"
          xlink:type="locator"/>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="id_footnote_elem_634421991_227"
          xlink:to="footnote_634370616"
          xlink:type="arc"/>
        <link:loc
          xlink:href="#id_footnote_elem_634437001_268"
          xlink:label="id_footnote_elem_634437001_268"
          xlink:type="locator"/>
        <link:footnote id="footnote_634437000" xlink:label="footnote_634437000" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:p style="font: 11px Arial, Helvetica, sans-serif;">
<xhtml:sup>(a)</xhtml:sup>
<xhtml:i>From
February 9, 2017
</xhtml:i>
</xhtml:p>

</link:footnote>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
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        <link:loc
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        <link:loc
          xlink:href="#id_footnote_elem_634437001_274"
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        <link:footnoteArc
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        <link:footnote id="footnote_634439041" xlink:label="footnote_634439041" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:p style="font: 11px Arial, Helvetica, sans-serif;">
<xhtml:sup>(a)</xhtml:sup>
<xhtml:i>From
October 8, 2015
</xhtml:i>
</xhtml:p>

</link:footnote>
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        <link:loc
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        <link:footnoteArc
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        <link:loc
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        <link:footnoteArc
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        <link:loc
          xlink:href="#id_footnote_elem_634439042_332"
          xlink:label="id_footnote_elem_634439042_332"
          xlink:type="locator"/>
        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="id_footnote_elem_634439042_332"
          xlink:to="footnote_634439041"
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        <link:loc
          xlink:href="#id_footnote_elem_634439042_335"
          xlink:label="id_footnote_elem_634439042_335"
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        <link:footnoteArc
          xlink:arcrole="http://www.xbrl.org/2003/arcrole/fact-footnote"
          xlink:from="id_footnote_elem_634439042_335"
          xlink:to="footnote_634439041"
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        <link:loc
          xlink:href="#id_footnote_elem_634441210_377"
          xlink:label="id_footnote_elem_634441210_377"
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        <link:footnote id="footnote_634441209" xlink:label="footnote_634441209" xlink:role="http://www.xbrl.org/2003/role/footnote" xlink:type="resource" xml:lang="en-US"><xhtml:p style="font: 11px Arial, Helvetica, sans-serif;">
<xhtml:sup>(a)</xhtml:sup>
<xhtml:i>From
December 19, 2017
</xhtml:i>
</xhtml:p>

</link:footnote>
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        <link:loc
          xlink:href="#id_footnote_elem_634441210_383"
          xlink:label="id_footnote_elem_634441210_383"
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        <link:footnoteArc
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          xlink:from="id_footnote_elem_634441210_383"
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        <link:loc
          xlink:href="#id_footnote_elem_634441210_386"
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        <link:footnoteArc
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