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            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_QD_AA_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:CreditQualityAxis">fmr:QDAAMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_QD_A_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:CreditQualityAxis">fmr:QDAMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_QD_BBB_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:CreditQualityAxis">fmr:QDBBBMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_QD_BB_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:CreditQualityAxis">fmr:QDBBMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_QD_B_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:CreditQualityAxis">fmr:QDBMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_QD_CCCCCC_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:CreditQualityAxis">fmr:QDCCCCCCMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_QD_NotRated_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:CreditQualityAxis">fmr:QDNotRatedMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_QD_ShortTermInvestmentsandNetOtherAssetsLiabilities_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:CreditQualityAxis">fmr:QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_AA_CorporateBonds_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:InvestmentTypeAxis">fmr:AACorporateBondsMember</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_AA_USTreasuryObligations_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:InvestmentTypeAxis">fmr:AAUSTreasuryObligationsMember</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_AA_ForeignGovernmentandGovernmentAgencyObligations_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:InvestmentTypeAxis">fmr:AAForeignGovernmentandGovernmentAgencyObligationsMember</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_AA_PreferredSecurities_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:InvestmentTypeAxis">fmr:AAPreferredSecuritiesMember</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_AA_ShortTermInvestmentsandNetOtherAssetsLiabilities_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:InvestmentTypeAxis">fmr:AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_GD_US_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:GeographicRegionAxis">country:US</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_GD_GB_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:GeographicRegionAxis">country:GB</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_GD_DE_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:GeographicRegionAxis">country:DE</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_GD_FR_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:GeographicRegionAxis">country:FR</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_GD_CA_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:GeographicRegionAxis">country:CA</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_GD_JP_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:GeographicRegionAxis">country:JP</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_GD_Multinational_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:GeographicRegionAxis">fmr:MultinationalMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_GD_AU_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:GeographicRegionAxis">country:AU</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_GD_LU_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:GeographicRegionAxis">country:LU</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_GD_Other_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:GeographicRegionAxis">fmr:OtherMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_TH_0_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:LargestHoldingAxis">fmr:TH0Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_TH_1_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:LargestHoldingAxis">fmr:TH1Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_TH_2_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:LargestHoldingAxis">fmr:TH2Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_TH_3_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:LargestHoldingAxis">fmr:TH3Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_TH_4_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:LargestHoldingAxis">fmr:TH4Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_TH_5_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:LargestHoldingAxis">fmr:TH5Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_TH_6_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:LargestHoldingAxis">fmr:TH6Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_TH_7_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:LargestHoldingAxis">fmr:TH7Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_TH_8_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:LargestHoldingAxis">fmr:TH8Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000241080_TH_9_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000241080Member</xbrldi:explicitMember>
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        <period>
            <instant>2026-06-30</instant>
        </period>
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    <context id="C000214977_ClassMember">
        <entity>
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            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000214977Member</xbrldi:explicitMember>
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        </entity>
        <period>
            <startDate>2025-12-31</startDate>
            <endDate>2026-06-30</endDate>
        </period>
    </context>
    <context id="C000214977_InstantMember">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000214977Member</xbrldi:explicitMember>
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        <period>
            <instant>2026-06-30</instant>
        </period>
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    <context id="C000214977_QD_AAA_Member">
        <entity>
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            <segment>
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            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000214977_QD_AA_Member">
        <entity>
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            <segment>
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            <instant>2026-06-30</instant>
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    <context id="C000214977_QD_A_Member">
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            </segment>
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        <period>
            <instant>2026-06-30</instant>
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    <context id="C000214977_QD_BBB_Member">
        <entity>
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            <segment>
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        <period>
            <instant>2026-06-30</instant>
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    <context id="C000214977_QD_BB_Member">
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            <segment>
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        <period>
            <instant>2026-06-30</instant>
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    <context id="C000214977_QD_B_Member">
        <entity>
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            <segment>
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            </segment>
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        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000214977_QD_NotRated_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
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            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000214977_QD_ShortTermInvestmentsandNetOtherAssetsLiabilities_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
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                <xbrldi:explicitMember dimension="oef:CreditQualityAxis">fmr:QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000214977_AA_ForeignGovernmentandGovernmentAgencyObligations_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:InvestmentTypeAxis">fmr:AAForeignGovernmentandGovernmentAgencyObligationsMember</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000214977Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000214977_AA_CorporateBonds_Member">
        <entity>
            <identifier scheme="http://www.sec.gov/CIK">0000035315</identifier>
            <segment>
                <xbrldi:explicitMember dimension="us-gaap:InvestmentTypeAxis">fmr:AACorporateBondsMember</xbrldi:explicitMember>
                <xbrldi:explicitMember dimension="oef:ClassAxis">fmr:C000214977Member</xbrldi:explicitMember>
            </segment>
        </entity>
        <period>
            <instant>2026-06-30</instant>
        </period>
    </context>
    <context id="C000214977_AA_PreferredSecurities_Member">
        <entity>
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    <oef:AnnlOrSemiAnnlStatementTextBlock contextRef="C000229124_ClassMember" id="ixv-136">This semi-annual shareholder report contains information about Fidelity&#xae; Series 5+ Year Inflation-Protected Bond Index Fund for the period January 1, 2026 to June 30, 2026.</oef:AnnlOrSemiAnnlStatementTextBlock>
    <oef:ShareholderReportAnnualOrSemiAnnual contextRef="C000229124_ClassMember" id="ixv-138">semi-annual shareholder report</oef:ShareholderReportAnnualOrSemiAnnual>
    <oef:AddlInfoTextBlock contextRef="C000229124_ClassMember" id="ixv-143">You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544.</oef:AddlInfoTextBlock>
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    <oef:ExpensesTextBlock contextRef="C000229124_ClassMember" id="ixv-155">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;What were your Fund costs for the last six months?&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(based on hypothetical $10,000 investment)&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="0" style="border-collapse:collapse;border-style:none;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:51%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs of a $10,000 investment&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs paid as a percentage of a $10,000 investment &lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:51%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fidelity&#xae; Series 5+ Year Inflation-Protected Bond Index Fund&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;0&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:6px;color:#000000;font-style:normal;vertical-align:4px;font-weight:normal;"&gt;A&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;0.00&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:6px;color:#000000;font-style:normal;vertical-align:4px;font-weight:normal;"&gt;B&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:6px;color:#000000;font-style:normal;vertical-align:4px;font-weight:normal;"&gt;A &lt;/span&gt;&lt;span style="font-family:'Fidelity Sans Cd';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Amount represents less than $.50&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:6px;color:#000000;font-style:normal;vertical-align:4px;font-weight:normal;"&gt;B &lt;/span&gt;&lt;span style="font-family:'Fidelity Sans Cd';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Amount represents less than 0.005%&lt;/span&gt;&lt;/div&gt;
&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
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    <oef:AddlFundStatisticsTextBlock contextRef="C000229124_ClassMember" id="ixv-206">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;Key Fund Statistics&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(as of June 30, 2026)&lt;/span&gt;&lt;/div&gt;
&lt;div&gt;&lt;span style="font-size:11px;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
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&lt;td style="width:32%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
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&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
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&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fund Size&lt;/span&gt;&lt;/div&gt;
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&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;13,760,670,900&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
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&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Number of Holdings&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;30&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
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&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Portfolio Turnover&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;24&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
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&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
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&#160;
COUPON DISTRIBUTION 
(% of Fund's net assets)


0.01 - 0.99%

29.2

&#160;


1 - 1.99%

53.1

&#160;


2 - 2.99%

16.5

&#160;


3 - 3.99%

0.6

&#160;




&#160;
&#160;
&#160;
U.S. Treasury Obligations

99.4


Short-Term Investments and Net Other Assets (Liabilities)

0.6




ASSET ALLOCATION (% of Fund's net assets)


&#160;



&#160;

U.S. Treasury Obligations - 99.4&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Short-Term Investments and Net Other Assets (Liabilities) - 0.6


&#160;






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      id="ixv-118304"
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    <oef:LargestHoldingsTableTextBlock contextRef="C000229124_ClassMember" id="ixv-375">TOP HOLDINGS(% of Fund's net assets)

&#160;

&#160;


US Treasury Notes

70.4


&#160;


US Treasury Bonds

29.0


&#160;


&#160;

99.4

&#160;



</oef:LargestHoldingsTableTextBlock>
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      unitRef="pure">0.290</oef:PctOfNav>
    <dei:DocumentPeriodEndDate contextRef="Trust" id="ixv-466">2026-06-30</dei:DocumentPeriodEndDate>
    <oef:FundName contextRef="C000229123_ClassMember" id="ixv-478">Fidelity&#xae; Series 0-5 Year Inflation-Protected Bond Index Fund</oef:FundName>
    <oef:ClassName contextRef="C000229123_ClassMember" id="ixv-481">Fidelity&#xae; Series 0-5 Year Inflation-Protected Bond Index Fund</oef:ClassName>
    <dei:TradingSymbol contextRef="C000229123_ClassMember" id="ixv-485">FSTZX</dei:TradingSymbol>
    <oef:AnnlOrSemiAnnlStatementTextBlock contextRef="C000229123_ClassMember" id="ixv-504">This semi-annual shareholder report contains information about Fidelity&#xae; Series 0-5 Year Inflation-Protected Bond Index Fund for the period January 1, 2026 to June 30, 2026.</oef:AnnlOrSemiAnnlStatementTextBlock>
    <oef:ShareholderReportAnnualOrSemiAnnual contextRef="C000229123_ClassMember" id="ixv-506">semi-annual shareholder report</oef:ShareholderReportAnnualOrSemiAnnual>
    <oef:AddlInfoTextBlock contextRef="C000229123_ClassMember" id="ixv-511">You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544.</oef:AddlInfoTextBlock>
    <oef:AddlInfoWebsite contextRef="C000229123_ClassMember" id="ixv-513">fundresearch.fidelity.com/prospectus/sec</oef:AddlInfoWebsite>
    <oef:AddlInfoPhoneNumber contextRef="C000229123_ClassMember" id="ixv-516">1-800-544-8544</oef:AddlInfoPhoneNumber>
    <oef:ExpensesTextBlock contextRef="C000229123_ClassMember" id="ixv-523">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;What were your Fund costs for the last six months?&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(based on hypothetical $10,000 investment)&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="0" style="border-collapse:collapse;border-style:none;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:51%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs of a $10,000 investment&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs paid as a percentage of a $10,000 investment &lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:51%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fidelity&#xae; Series 0-5 Year Inflation-Protected Bond Index Fund&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;0&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:6px;color:#000000;font-style:normal;vertical-align:4px;font-weight:normal;"&gt;A&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;0.00&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:6px;color:#000000;font-style:normal;vertical-align:4px;font-weight:normal;"&gt;B&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:6px;color:#000000;font-style:normal;vertical-align:4px;font-weight:normal;"&gt;A &lt;/span&gt;&lt;span style="font-family:'Fidelity Sans Cd';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Amount represents less than $.50&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:6px;color:#000000;font-style:normal;vertical-align:4px;font-weight:normal;"&gt;B &lt;/span&gt;&lt;span style="font-family:'Fidelity Sans Cd';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Amount represents less than 0.005%&lt;/span&gt;&lt;/div&gt;
&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:ExpensesTextBlock>
    <oef:ExpensesPaidAmt
      contextRef="C000229123_ClassMember"
      decimals="0"
      id="ixv-118308"
      unitRef="usd">0</oef:ExpensesPaidAmt>
    <oef:ExpenseRatioPct
      contextRef="C000229123_ClassMember"
      decimals="INF"
      id="ixv-118309"
      unitRef="pure">0.0000</oef:ExpenseRatioPct>
    <oef:AddlFundStatisticsTextBlock contextRef="C000229123_ClassMember" id="ixv-574">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;Key Fund Statistics&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(as of June 30, 2026)&lt;/span&gt;&lt;/div&gt;
&lt;div&gt;&lt;span style="font-size:11px;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="1" style="border-collapse:separate;border-style:none;margin:auto;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:63%; " valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:bold;"&gt;KEY FACTS&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fund Size&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;11,148,513,107&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Number of Holdings&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;26&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Portfolio Turnover&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;15&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:AddlFundStatisticsTextBlock>
    <us-gaap:AssetsNet
      contextRef="C000229123_InstantMember"
      decimals="0"
      id="ixv-118310"
      unitRef="usd">11148513107</us-gaap:AssetsNet>
    <oef:HoldingsCount
      contextRef="C000229123_InstantMember"
      decimals="INF"
      id="ixv-118311"
      unitRef="holding">26</oef:HoldingsCount>
    <us-gaap:InvestmentCompanyPortfolioTurnover
      contextRef="C000229123_ClassMember"
      decimals="INF"
      id="ixv-118312"
      unitRef="pure">0.15</us-gaap:InvestmentCompanyPortfolioTurnover>
    <oef:HoldingsTableTextBlock contextRef="C000229123_ClassMember" id="ixv-634">
&#160;
COUPON DISTRIBUTION 
(% of Fund's net assets)


0.01 - 0.99%

45.8

&#160;


1 - 1.99%

33.5

&#160;


2 - 2.99%

14.2

&#160;


3 - 3.99%

4.1

&#160;




&#160;
&#160;
&#160;
U.S. Treasury Obligations

97.6


Short-Term Investments and Net Other Assets (Liabilities)

2.4




ASSET ALLOCATION (% of Fund's net assets)


&#160;



&#160;

U.S. Treasury Obligations - 97.6&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Short-Term Investments and Net Other Assets (Liabilities) - 2.4


&#160;






</oef:HoldingsTableTextBlock>
    <oef:PctOfNav
      contextRef="C000229123_CD_0_Member"
      decimals="INF"
      id="ixv-118313"
      unitRef="pure">0.458</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000229123_CD_1_Member"
      decimals="INF"
      id="ixv-118314"
      unitRef="pure">0.335</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000229123_CD_2_Member"
      decimals="INF"
      id="ixv-118315"
      unitRef="pure">0.142</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000229123_CD_3_Member"
      decimals="INF"
      id="ixv-118316"
      unitRef="pure">0.041</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000229123_AA_USTreasuryObligations_Member"
      decimals="INF"
      id="ixv-118317"
      unitRef="pure">0.976</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000229123_AA_ShortTermInvestmentsandNetOtherAssetsLiabilities_Member"
      decimals="INF"
      id="ixv-118318"
      unitRef="pure">0.024</oef:PctOfNav>
    <oef:LargestHoldingsTableTextBlock contextRef="C000229123_ClassMember" id="ixv-743">TOP HOLDINGS(% of Fund's net assets)

&#160;

&#160;


US Treasury Notes

88.2


&#160;


US Treasury Bonds

9.4


&#160;


&#160;

97.6

&#160;



</oef:LargestHoldingsTableTextBlock>
    <oef:PctOfNav
      contextRef="C000229123_TH_0_Member"
      decimals="INF"
      id="ixv-118319"
      unitRef="pure">0.882</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000229123_TH_1_Member"
      decimals="INF"
      id="ixv-118320"
      unitRef="pure">0.094</oef:PctOfNav>
    <dei:DocumentPeriodEndDate contextRef="Trust" id="ixv-834">2026-06-30</dei:DocumentPeriodEndDate>
    <oef:FundName contextRef="C000200824_ClassMember" id="ixv-846">Fidelity&#xae; SAI Municipal Income Fund</oef:FundName>
    <oef:ClassName contextRef="C000200824_ClassMember" id="ixv-849">Fidelity&#xae; SAI Municipal Income Fund</oef:ClassName>
    <dei:TradingSymbol contextRef="C000200824_ClassMember" id="ixv-853">FSMNX</dei:TradingSymbol>
    <oef:AnnlOrSemiAnnlStatementTextBlock contextRef="C000200824_ClassMember" id="ixv-872">This semi-annual shareholder report contains information about Fidelity&#xae; SAI Municipal Income Fund for the period January 1, 2026 to June 30, 2026.</oef:AnnlOrSemiAnnlStatementTextBlock>
    <oef:ShareholderReportAnnualOrSemiAnnual contextRef="C000200824_ClassMember" id="ixv-874">semi-annual shareholder report</oef:ShareholderReportAnnualOrSemiAnnual>
    <oef:AddlInfoTextBlock contextRef="C000200824_ClassMember" id="ixv-879">You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-3455 or by sending an e-mail to fidfunddocuments@fidelity.com.</oef:AddlInfoTextBlock>
    <oef:AddlInfoWebsite contextRef="C000200824_ClassMember" id="ixv-881">fundresearch.fidelity.com/prospectus/sec</oef:AddlInfoWebsite>
    <oef:AddlInfoPhoneNumber contextRef="C000200824_ClassMember" id="ixv-884">1-800-544-3455</oef:AddlInfoPhoneNumber>
    <oef:AddlInfoEmail contextRef="C000200824_ClassMember" id="ixv-887">fidfunddocuments@fidelity.com</oef:AddlInfoEmail>
    <oef:ExpensesTextBlock contextRef="C000200824_ClassMember" id="ixv-894">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;What were your Fund costs for the last six months?&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(based on hypothetical $10,000 investment)&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="0" style="border-collapse:collapse;border-style:none;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:51%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs of a $10,000 investment&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs paid as a percentage of a $10,000 investment &lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:51%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fidelity&#xae; SAI Municipal Income Fund&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;17&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;0.34&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:ExpensesTextBlock>
    <oef:ExpensesPaidAmt
      contextRef="C000200824_ClassMember"
      decimals="0"
      id="ixv-118321"
      unitRef="usd">17</oef:ExpensesPaidAmt>
    <oef:ExpenseRatioPct
      contextRef="C000200824_ClassMember"
      decimals="INF"
      id="ixv-118322"
      unitRef="pure">0.0034</oef:ExpenseRatioPct>
    <oef:AddlFundStatisticsTextBlock contextRef="C000200824_ClassMember" id="ixv-935">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;Key Fund Statistics&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(as of June 30, 2026)&lt;/span&gt;&lt;/div&gt;
&lt;div&gt;&lt;span style="font-size:11px;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="1" style="border-collapse:separate;border-style:none;margin:auto;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:63%; " valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:bold;"&gt;KEY FACTS&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fund Size&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;3,632,339,324&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Number of Holdings&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;1,779&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Portfolio Turnover&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;11&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:AddlFundStatisticsTextBlock>
    <us-gaap:AssetsNet
      contextRef="C000200824_InstantMember"
      decimals="0"
      id="ixv-118323"
      unitRef="usd">3632339324</us-gaap:AssetsNet>
    <oef:HoldingsCount
      contextRef="C000200824_InstantMember"
      decimals="INF"
      id="ixv-118324"
      unitRef="holding">1779</oef:HoldingsCount>
    <us-gaap:InvestmentCompanyPortfolioTurnover
      contextRef="C000200824_ClassMember"
      decimals="INF"
      id="ixv-118325"
      unitRef="pure">0.11</us-gaap:InvestmentCompanyPortfolioTurnover>
    <oef:HoldingsTableTextBlock contextRef="C000200824_ClassMember" id="ixv-995">
&#160;
REVENUE SOURCES
 (% of Fund's net assets)


General Obligations

38.5

&#160;


Transportation

19.3

&#160;


Special Tax

8.7

&#160;


Health Care

8.3

&#160;


Electric Utilities

5.7

&#160;


Education

5.1

&#160;


Others(Individually Less Than 5%)

11.3

&#160;


96.9

&#160;


&#160;




&#160;
AAA

6.5


AA

43.6


A

36.3


BBB

5.9


BB

1.4


B

0.0


Not Rated

3.2


Short-Term Investments and Net Other Assets (Liabilities)

3.1




QUALITY DIVERSIFICATION (% of Fund's net assets)


&#160;



&#160;

AAA - 6.5&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

AA - 43.6&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

A - 36.3&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

BBB - 5.9&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

BB - 1.4&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

B - 0.0&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Not Rated - 3.2&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Short-Term Investments and Net Other Assets (Liabilities) - 3.1


&#160;


We have used ratings from Moody's Investors Service, Inc. Where Moody's&#xae; ratings are not available, we have used S&amp;P&#xae; ratings. All ratings are as of the date indicated and do not reflect subsequent changes.




&#160;
&#160;
&#160;
TOP STATES
(% of Fund's net assets)


Alabama

9.8


Texas

9.2


New York

8.8


Illinois

7.6


California

6.1


&#160;

&#160;




&#160;
</oef:HoldingsTableTextBlock>
    <oef:PctOfNav
      contextRef="C000200824_RS_0_Member"
      decimals="INF"
      id="ixv-118326"
      unitRef="pure">0.385</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_RS_1_Member"
      decimals="INF"
      id="ixv-118327"
      unitRef="pure">0.193</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_RS_2_Member"
      decimals="INF"
      id="ixv-118328"
      unitRef="pure">0.087</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_RS_3_Member"
      decimals="INF"
      id="ixv-118329"
      unitRef="pure">0.083</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_RS_4_Member"
      decimals="INF"
      id="ixv-118330"
      unitRef="pure">0.057</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_RS_5_Member"
      decimals="INF"
      id="ixv-118331"
      unitRef="pure">0.051</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_RS_6_Member"
      decimals="INF"
      id="ixv-118332"
      unitRef="pure">0.113</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_QD_AAA_Member"
      decimals="INF"
      id="ixv-118333"
      unitRef="pure">0.065</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_QD_AA_Member"
      decimals="INF"
      id="ixv-118334"
      unitRef="pure">0.436</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_QD_A_Member"
      decimals="INF"
      id="ixv-118335"
      unitRef="pure">0.363</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_QD_BBB_Member"
      decimals="INF"
      id="ixv-118336"
      unitRef="pure">0.059</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_QD_BB_Member"
      decimals="INF"
      id="ixv-118337"
      unitRef="pure">0.014</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_QD_B_Member"
      decimals="INF"
      id="ixv-118338"
      unitRef="pure">0.000</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_QD_NotRated_Member"
      decimals="INF"
      id="ixv-118339"
      unitRef="pure">0.032</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_QD_ShortTermInvestmentsandNetOtherAssetsLiabilities_Member"
      decimals="INF"
      id="ixv-118340"
      unitRef="pure">0.031</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_TS_0_Member"
      decimals="INF"
      id="ixv-118341"
      unitRef="pure">0.098</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_TS_1_Member"
      decimals="INF"
      id="ixv-118342"
      unitRef="pure">0.092</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_TS_2_Member"
      decimals="INF"
      id="ixv-118343"
      unitRef="pure">0.088</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_TS_3_Member"
      decimals="INF"
      id="ixv-118344"
      unitRef="pure">0.076</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000200824_TS_4_Member"
      decimals="INF"
      id="ixv-118345"
      unitRef="pure">0.061</oef:PctOfNav>
    <dei:DocumentPeriodEndDate contextRef="Trust" id="ixv-1318">2026-06-30</dei:DocumentPeriodEndDate>
    <oef:FundName contextRef="C000241080_ClassMember" id="ixv-1330">Fidelity&#xae; SAI International Credit Fund</oef:FundName>
    <oef:ClassName contextRef="C000241080_ClassMember" id="ixv-1333">Fidelity&#xae; SAI International Credit Fund</oef:ClassName>
    <dei:TradingSymbol contextRef="C000241080_ClassMember" id="ixv-1337">FSNDX</dei:TradingSymbol>
    <oef:AnnlOrSemiAnnlStatementTextBlock contextRef="C000241080_ClassMember" id="ixv-1356">This semi-annual shareholder report contains information about Fidelity&#xae; SAI International Credit Fund for the period January 1, 2026 to June 30, 2026.</oef:AnnlOrSemiAnnlStatementTextBlock>
    <oef:ShareholderReportAnnualOrSemiAnnual contextRef="C000241080_ClassMember" id="ixv-1358">semi-annual shareholder report</oef:ShareholderReportAnnualOrSemiAnnual>
    <oef:AddlInfoTextBlock contextRef="C000241080_ClassMember" id="ixv-1363">You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-3455 or by sending an e-mail to fidfunddocuments@fidelity.com.</oef:AddlInfoTextBlock>
    <oef:AddlInfoWebsite contextRef="C000241080_ClassMember" id="ixv-1365">fundresearch.fidelity.com/prospectus/sec</oef:AddlInfoWebsite>
    <oef:AddlInfoPhoneNumber contextRef="C000241080_ClassMember" id="ixv-1368">1-800-544-3455</oef:AddlInfoPhoneNumber>
    <oef:AddlInfoEmail contextRef="C000241080_ClassMember" id="ixv-1371">fidfunddocuments@fidelity.com</oef:AddlInfoEmail>
    <oef:ExpensesTextBlock contextRef="C000241080_ClassMember" id="ixv-1378">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;What were your Fund costs for the last six months?&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(based on hypothetical $10,000 investment)&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="0" style="border-collapse:collapse;border-style:none;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:51%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs of a $10,000 investment&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs paid as a percentage of a $10,000 investment &lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:51%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fidelity&#xae; SAI International Credit Fund&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;21&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;0.41&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:ExpensesTextBlock>
    <oef:ExpensesPaidAmt
      contextRef="C000241080_ClassMember"
      decimals="0"
      id="ixv-118346"
      unitRef="usd">21</oef:ExpensesPaidAmt>
    <oef:ExpenseRatioPct
      contextRef="C000241080_ClassMember"
      decimals="INF"
      id="ixv-118347"
      unitRef="pure">0.0041</oef:ExpenseRatioPct>
    <oef:AddlFundStatisticsTextBlock contextRef="C000241080_ClassMember" id="ixv-1419">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;Key Fund Statistics&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(as of June 30, 2026)&lt;/span&gt;&lt;/div&gt;
&lt;div&gt;&lt;span style="font-size:11px;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="1" style="border-collapse:separate;border-style:none;margin:auto;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:63%; " valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:bold;"&gt;KEY FACTS&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fund Size&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;2,298,495,269&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Number of Holdings&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;345&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Portfolio Turnover&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;28&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:AddlFundStatisticsTextBlock>
    <us-gaap:AssetsNet
      contextRef="C000241080_InstantMember"
      decimals="0"
      id="ixv-118348"
      unitRef="usd">2298495269</us-gaap:AssetsNet>
    <oef:HoldingsCount
      contextRef="C000241080_InstantMember"
      decimals="INF"
      id="ixv-118349"
      unitRef="holding">345</oef:HoldingsCount>
    <us-gaap:InvestmentCompanyPortfolioTurnover
      contextRef="C000241080_ClassMember"
      decimals="INF"
      id="ixv-118350"
      unitRef="pure">0.28</us-gaap:InvestmentCompanyPortfolioTurnover>
    <oef:HoldingsTableTextBlock contextRef="C000241080_ClassMember" id="ixv-1479">
&#160;
U.S. Government and U.S. Government Agency Obligations

21.7


AAA

12.5


AA

0.1


A

14.8


BBB

31.5


BB

4.6


B

1.6


CCC,CC,C

0.1


Not Rated

6.5


Short-Term Investments and Net Other Assets (Liabilities)

6.6




QUALITY DIVERSIFICATION (% of Fund's net assets)


&#160;



&#160;

U.S. Government and U.S. Government Agency Obligations - 21.7


&#160;

AAA - 12.5&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

AA - 0.1&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

A - 14.8&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

BBB - 31.5&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

BB - 4.6&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

B - 1.6&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

CCC,CC,C - 0.1&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Not Rated - 6.5&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Short-Term Investments and Net Other Assets (Liabilities) - 6.6


&#160;


We have used ratings from Moody's Investors Service, Inc. Where Moody's&#xae; ratings are not available, we have used S&amp;P&#xae; ratings. All ratings are as of the date indicated and do not reflect subsequent changes.




&#160;
&#160;
&#160;
&#160;
Corporate Bonds

59.0


U.S. Treasury Obligations

21.7


Foreign Government and Government Agency Obligations

11.4


Preferred Securities

1.3


Short-Term Investments and Net Other Assets (Liabilities)

6.6




ASSET ALLOCATION (% of Fund's net assets)


&#160;



&#160;

Corporate Bonds - 59.0&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

U.S. Treasury Obligations - 21.7&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Foreign Government and Government Agency Obligations - 11.4


&#160;

Preferred Securities - 1.3&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Short-Term Investments and Net Other Assets (Liabilities) - 6.6


&#160;






United States

33.4


United Kingdom

16.5


Germany

12.3


France

5.7


Canada

5.4


Japan

4.1


Multi-national

3.9


Australia

3.1


Luxembourg

3.0


Others

12.6




GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)


&#160;



&#160;

United States - 33.4&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

United Kingdom - 16.5&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Germany - 12.3&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

France - 5.7&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Canada - 5.4&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Japan - 4.1&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Multi-national - 3.9&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Australia - 3.1&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Luxembourg - 3.0&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Others - 12.6&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;




&#160;




&#160;
&#160;
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      id="ixv-118364"
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      id="ixv-118371"
      unitRef="pure">0.041</oef:PctOfNav>
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      decimals="INF"
      id="ixv-118372"
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      decimals="INF"
      id="ixv-118373"
      unitRef="pure">0.031</oef:PctOfNav>
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      decimals="INF"
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      unitRef="pure">0.126</oef:PctOfNav>
    <oef:LargestHoldingsTableTextBlock contextRef="C000241080_ClassMember" id="ixv-1901">TOP HOLDINGS(% of Fund's net assets)

&#160;

&#160;


US Treasury Notes

15.7


&#160;


US Treasury Bonds

6.0


&#160;


KfW

4.9


&#160;


Canadian Government

3.6


&#160;


European Union

3.1


&#160;


Japan Government

3.1


&#160;


HSBC Holdings PLC

1.3


&#160;


UBS Group AG

1.2


&#160;


NatWest Group PLC

1.1


&#160;


BNP Paribas SA

1.1


&#160;


&#160;

41.1

&#160;



</oef:LargestHoldingsTableTextBlock>
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      decimals="INF"
      id="ixv-118377"
      unitRef="pure">0.060</oef:PctOfNav>
    <oef:PctOfNav
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      decimals="INF"
      id="ixv-118378"
      unitRef="pure">0.049</oef:PctOfNav>
    <oef:PctOfNav
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      decimals="INF"
      id="ixv-118379"
      unitRef="pure">0.036</oef:PctOfNav>
    <oef:PctOfNav
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      id="ixv-118380"
      unitRef="pure">0.031</oef:PctOfNav>
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      decimals="INF"
      id="ixv-118381"
      unitRef="pure">0.031</oef:PctOfNav>
    <oef:PctOfNav
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      id="ixv-118382"
      unitRef="pure">0.013</oef:PctOfNav>
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      id="ixv-118383"
      unitRef="pure">0.012</oef:PctOfNav>
    <oef:PctOfNav
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      decimals="INF"
      id="ixv-118384"
      unitRef="pure">0.011</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000241080_TH_9_Member"
      decimals="INF"
      id="ixv-118385"
      unitRef="pure">0.011</oef:PctOfNav>
    <dei:DocumentPeriodEndDate contextRef="Trust" id="ixv-2072">2026-06-30</dei:DocumentPeriodEndDate>
    <oef:FundName contextRef="C000214977_ClassMember" id="ixv-2084">Fidelity&#xae; International Bond Index Fund</oef:FundName>
    <oef:ClassName contextRef="C000214977_ClassMember" id="ixv-2087">Fidelity&#xae; International Bond Index Fund</oef:ClassName>
    <dei:TradingSymbol contextRef="C000214977_ClassMember" id="ixv-2091">FBIIX</dei:TradingSymbol>
    <oef:AnnlOrSemiAnnlStatementTextBlock contextRef="C000214977_ClassMember" id="ixv-2110">This semi-annual shareholder report contains information about Fidelity&#xae; International Bond Index Fund for the period January 1, 2026 to June 30, 2026.</oef:AnnlOrSemiAnnlStatementTextBlock>
    <oef:ShareholderReportAnnualOrSemiAnnual contextRef="C000214977_ClassMember" id="ixv-2112">semi-annual shareholder report</oef:ShareholderReportAnnualOrSemiAnnual>
    <oef:AddlInfoTextBlock contextRef="C000214977_ClassMember" id="ixv-2117">You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.</oef:AddlInfoTextBlock>
    <oef:AddlInfoWebsite contextRef="C000214977_ClassMember" id="ixv-2119">fundresearch.fidelity.com/prospectus/sec</oef:AddlInfoWebsite>
    <oef:AddlInfoPhoneNumber contextRef="C000214977_ClassMember" id="ixv-2122">1-800-544-8544</oef:AddlInfoPhoneNumber>
    <oef:AddlInfoEmail contextRef="C000214977_ClassMember" id="ixv-2125">fidfunddocuments@fidelity.com</oef:AddlInfoEmail>
    <oef:ExpensesTextBlock contextRef="C000214977_ClassMember" id="ixv-2132">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;What were your Fund costs for the last six months?&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(based on hypothetical $10,000 investment)&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="0" style="border-collapse:collapse;border-style:none;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:51%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs of a $10,000 investment&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs paid as a percentage of a $10,000 investment &lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:51%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fidelity&#xae; International Bond Index Fund&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;3&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;0.06&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:ExpensesTextBlock>
    <oef:ExpensesPaidAmt
      contextRef="C000214977_ClassMember"
      decimals="0"
      id="ixv-118386"
      unitRef="usd">3</oef:ExpensesPaidAmt>
    <oef:ExpenseRatioPct
      contextRef="C000214977_ClassMember"
      decimals="INF"
      id="ixv-118387"
      unitRef="pure">0.0006</oef:ExpenseRatioPct>
    <oef:AddlFundStatisticsTextBlock contextRef="C000214977_ClassMember" id="ixv-2173">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;Key Fund Statistics&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(as of June 30, 2026)&lt;/span&gt;&lt;/div&gt;
&lt;div&gt;&lt;span style="font-size:11px;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="1" style="border-collapse:separate;border-style:none;margin:auto;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:63%; " valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:bold;"&gt;KEY FACTS&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fund Size&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;1,360,923,682&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Number of Holdings&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;2,324&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Portfolio Turnover&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;33&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:AddlFundStatisticsTextBlock>
    <us-gaap:AssetsNet
      contextRef="C000214977_InstantMember"
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      id="ixv-118388"
      unitRef="usd">1360923682</us-gaap:AssetsNet>
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      contextRef="C000214977_InstantMember"
      decimals="INF"
      id="ixv-118389"
      unitRef="holding">2324</oef:HoldingsCount>
    <us-gaap:InvestmentCompanyPortfolioTurnover
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      id="ixv-118390"
      unitRef="pure">0.33</us-gaap:InvestmentCompanyPortfolioTurnover>
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&#160;
AAA

18.9


AA

18.3


A

22.0


BBB

12.9


BB

0.4


B

0.0


Not Rated

26.3


Short-Term Investments and Net Other Assets (Liabilities)

1.2




QUALITY DIVERSIFICATION (% of Fund's net assets)


&#160;



&#160;

AAA - 18.9&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

AA - 18.3&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

A - 22.0&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

BBB - 12.9&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

BB - 0.4&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

B - 0.0&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Not Rated - 26.3&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Short-Term Investments and Net Other Assets (Liabilities) - 1.2


&#160;


We have used ratings from Moody's Investors Service, Inc. Where Moody's&#xae; ratings are not available, we have used S&amp;P&#xae; ratings. All ratings are as of the date indicated and do not reflect subsequent changes.




&#160;
&#160;
&#160;
&#160;
Foreign Government and Government Agency Obligations

65.7


Corporate Bonds

32.4


Preferred Securities

0.7


Short-Term Investments and Net Other Assets (Liabilities)

1.2




ASSET ALLOCATION (% of Fund's net assets)


&#160;



&#160;

Foreign Government and Government Agency Obligations - 65.7


&#160;

Corporate Bonds - 32.4&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Preferred Securities - 0.7&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Short-Term Investments and Net Other Assets (Liabilities) - 1.2


&#160;






France

14.7


Japan

11.9


Germany

10.1


United Kingdom

8.5


Canada

8.5


Italy

8.4


United States

6.3


Spain

5.9


Multi-national

4.6


Others

21.1




GEOGRAPHIC DIVERSIFICATION (% of Fund's net assets)


&#160;



&#160;

France - 14.7&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Japan - 11.9&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Germany - 10.1&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

United Kingdom - 8.5&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Canada - 8.5&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Italy - 8.4&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

United States - 6.3&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Spain - 5.9&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Multi-national - 4.6&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Others - 21.1&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;




&#160;




&#160;
&#160;
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      unitRef="pure">0.211</oef:PctOfNav>
    <oef:LargestHoldingsTableTextBlock contextRef="C000214977_ClassMember" id="ixv-2616">TOP HOLDINGS(% of Fund's net assets)

&#160;

&#160;


Japan Government

11.5


&#160;


French Government

7.8


&#160;


Italian Republic

7.2


&#160;


United Kingdom of Great Britain and Northern Ireland

6.0


&#160;


German Federal Republic

5.1


&#160;


Spanish Kingdom

4.6


&#160;


Canadian Government

2.5


&#160;


Australian Commonwealth

1.9


&#160;


European Union

1.8


&#160;


Kingdom of Belgium

1.7


&#160;


&#160;

50.1

&#160;



</oef:LargestHoldingsTableTextBlock>
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      unitRef="pure">0.115</oef:PctOfNav>
    <oef:PctOfNav
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      id="ixv-118414"
      unitRef="pure">0.078</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000214977_TH_2_Member"
      decimals="INF"
      id="ixv-118415"
      unitRef="pure">0.072</oef:PctOfNav>
    <oef:PctOfNav
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      id="ixv-118416"
      unitRef="pure">0.060</oef:PctOfNav>
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      unitRef="pure">0.051</oef:PctOfNav>
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      id="ixv-118418"
      unitRef="pure">0.046</oef:PctOfNav>
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      decimals="INF"
      id="ixv-118420"
      unitRef="pure">0.019</oef:PctOfNav>
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      decimals="INF"
      id="ixv-118421"
      unitRef="pure">0.018</oef:PctOfNav>
    <oef:PctOfNav
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      decimals="INF"
      id="ixv-118422"
      unitRef="pure">0.017</oef:PctOfNav>
    <dei:DocumentPeriodEndDate contextRef="Trust" id="ixv-2787">2026-06-30</dei:DocumentPeriodEndDate>
    <oef:FundName contextRef="C000113282_ClassMember" id="ixv-2799">Fidelity&#xae; Inflation-Protected Bond Index Fund</oef:FundName>
    <oef:ClassName contextRef="C000113282_ClassMember" id="ixv-2802">Fidelity&#xae; Inflation-Protected Bond Index Fund</oef:ClassName>
    <dei:TradingSymbol contextRef="C000113282_ClassMember" id="ixv-2806">FIPDX</dei:TradingSymbol>
    <oef:AnnlOrSemiAnnlStatementTextBlock contextRef="C000113282_ClassMember" id="ixv-2825">This semi-annual shareholder report contains information about Fidelity&#xae; Inflation-Protected Bond Index Fund for the period January 1, 2026 to June 30, 2026.</oef:AnnlOrSemiAnnlStatementTextBlock>
    <oef:ShareholderReportAnnualOrSemiAnnual contextRef="C000113282_ClassMember" id="ixv-2827">semi-annual shareholder report</oef:ShareholderReportAnnualOrSemiAnnual>
    <oef:AddlInfoTextBlock contextRef="C000113282_ClassMember" id="ixv-2832">You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-8544 or by sending an e-mail to fidfunddocuments@fidelity.com.</oef:AddlInfoTextBlock>
    <oef:AddlInfoWebsite contextRef="C000113282_ClassMember" id="ixv-2834">fundresearch.fidelity.com/prospectus/sec</oef:AddlInfoWebsite>
    <oef:AddlInfoPhoneNumber contextRef="C000113282_ClassMember" id="ixv-2837">1-800-544-8544</oef:AddlInfoPhoneNumber>
    <oef:AddlInfoEmail contextRef="C000113282_ClassMember" id="ixv-2840">fidfunddocuments@fidelity.com</oef:AddlInfoEmail>
    <oef:ExpensesTextBlock contextRef="C000113282_ClassMember" id="ixv-2847">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;What were your Fund costs for the last six months?&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(based on hypothetical $10,000 investment)&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="0" style="border-collapse:collapse;border-style:none;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:51%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs of a $10,000 investment&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs paid as a percentage of a $10,000 investment &lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:51%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fidelity&#xae; Inflation-Protected Bond Index Fund&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;3&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;0.05&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:ExpensesTextBlock>
    <oef:ExpensesPaidAmt
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    <oef:ExpenseRatioPct
      contextRef="C000113282_ClassMember"
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      id="ixv-118424"
      unitRef="pure">0.0005</oef:ExpenseRatioPct>
    <oef:AddlFundStatisticsTextBlock contextRef="C000113282_ClassMember" id="ixv-2888">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;Key Fund Statistics&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(as of June 30, 2026)&lt;/span&gt;&lt;/div&gt;
&lt;div&gt;&lt;span style="font-size:11px;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="1" style="border-collapse:separate;border-style:none;margin:auto;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:63%; " valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:bold;"&gt;KEY FACTS&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fund Size&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;11,684,697,223&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Number of Holdings&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;49&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Portfolio Turnover&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;23&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:AddlFundStatisticsTextBlock>
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      contextRef="C000113282_InstantMember"
      decimals="0"
      id="ixv-118425"
      unitRef="usd">11684697223</us-gaap:AssetsNet>
    <oef:HoldingsCount
      contextRef="C000113282_InstantMember"
      decimals="INF"
      id="ixv-118426"
      unitRef="holding">49</oef:HoldingsCount>
    <us-gaap:InvestmentCompanyPortfolioTurnover
      contextRef="C000113282_ClassMember"
      decimals="INF"
      id="ixv-118427"
      unitRef="pure">0.23</us-gaap:InvestmentCompanyPortfolioTurnover>
    <oef:HoldingsTableTextBlock contextRef="C000113282_ClassMember" id="ixv-2948">
&#160;
COUPON DISTRIBUTION 
(% of Fund's net assets)


0.01 - 0.99%

36.2

&#160;


1 - 1.99%

44.4

&#160;


2 - 2.99%

15.3

&#160;


3 - 3.99%

3.5

&#160;




&#160;
&#160;
&#160;
U.S. Treasury Obligations

99.4


Short-Term Investments and Net Other Assets (Liabilities)

0.6




ASSET ALLOCATION (% of Fund's net assets)


&#160;



&#160;

U.S. Treasury Obligations - 99.4&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Short-Term Investments and Net Other Assets (Liabilities) - 0.6


&#160;






</oef:HoldingsTableTextBlock>
    <oef:PctOfNav
      contextRef="C000113282_CD_0_Member"
      decimals="INF"
      id="ixv-118428"
      unitRef="pure">0.362</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000113282_CD_1_Member"
      decimals="INF"
      id="ixv-118429"
      unitRef="pure">0.444</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000113282_CD_2_Member"
      decimals="INF"
      id="ixv-118430"
      unitRef="pure">0.153</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000113282_CD_3_Member"
      decimals="INF"
      id="ixv-118431"
      unitRef="pure">0.035</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000113282_AA_USTreasuryObligations_Member"
      decimals="INF"
      id="ixv-118432"
      unitRef="pure">0.994</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000113282_AA_ShortTermInvestmentsandNetOtherAssetsLiabilities_Member"
      decimals="INF"
      id="ixv-118433"
      unitRef="pure">0.006</oef:PctOfNav>
    <oef:LargestHoldingsTableTextBlock contextRef="C000113282_ClassMember" id="ixv-3057">TOP HOLDINGS(% of Fund's net assets)

&#160;

&#160;


US Treasury Notes

79.4


&#160;


US Treasury Bonds

20.0


&#160;


&#160;

99.4

&#160;



</oef:LargestHoldingsTableTextBlock>
    <oef:PctOfNav
      contextRef="C000113282_TH_0_Member"
      decimals="INF"
      id="ixv-118434"
      unitRef="pure">0.794</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000113282_TH_1_Member"
      decimals="INF"
      id="ixv-118435"
      unitRef="pure">0.200</oef:PctOfNav>
    <dei:DocumentPeriodEndDate contextRef="Trust" id="ixv-3148">2026-06-30</dei:DocumentPeriodEndDate>
    <oef:FundName contextRef="C000252148_ClassMember" id="ixv-3160">Fidelity&#xae; SAI Inflation-Protected Bond Index Fund</oef:FundName>
    <oef:ClassName contextRef="C000252148_ClassMember" id="ixv-3163">Fidelity&#xae; SAI Inflation-Protected Bond Index Fund</oef:ClassName>
    <dei:TradingSymbol contextRef="C000252148_ClassMember" id="ixv-3167">FSPWX</dei:TradingSymbol>
    <oef:AnnlOrSemiAnnlStatementTextBlock contextRef="C000252148_ClassMember" id="ixv-3186">This semi-annual shareholder report contains information about Fidelity&#xae; SAI Inflation-Protected Bond Index Fund for the period January 1, 2026 to June 30, 2026.</oef:AnnlOrSemiAnnlStatementTextBlock>
    <oef:ShareholderReportAnnualOrSemiAnnual contextRef="C000252148_ClassMember" id="ixv-3188">semi-annual shareholder report</oef:ShareholderReportAnnualOrSemiAnnual>
    <oef:AddlInfoTextBlock contextRef="C000252148_ClassMember" id="ixv-3193">You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-3455 or by sending an e-mail to fidfunddocuments@fidelity.com.</oef:AddlInfoTextBlock>
    <oef:AddlInfoWebsite contextRef="C000252148_ClassMember" id="ixv-3195">fundresearch.fidelity.com/prospectus/sec</oef:AddlInfoWebsite>
    <oef:AddlInfoPhoneNumber contextRef="C000252148_ClassMember" id="ixv-3198">1-800-544-3455</oef:AddlInfoPhoneNumber>
    <oef:AddlInfoEmail contextRef="C000252148_ClassMember" id="ixv-3201">fidfunddocuments@fidelity.com</oef:AddlInfoEmail>
    <oef:ExpensesTextBlock contextRef="C000252148_ClassMember" id="ixv-3208">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;What were your Fund costs for the last six months?&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(based on hypothetical $10,000 investment)&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="0" style="border-collapse:collapse;border-style:none;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:51%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs of a $10,000 investment&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs paid as a percentage of a $10,000 investment &lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:51%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fidelity&#xae; SAI Inflation-Protected Bond Index Fund&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;3&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;0.05&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:ExpensesTextBlock>
    <oef:ExpensesPaidAmt
      contextRef="C000252148_ClassMember"
      decimals="0"
      id="ixv-118436"
      unitRef="usd">3</oef:ExpensesPaidAmt>
    <oef:ExpenseRatioPct
      contextRef="C000252148_ClassMember"
      decimals="INF"
      id="ixv-118437"
      unitRef="pure">0.0005</oef:ExpenseRatioPct>
    <oef:AddlFundStatisticsTextBlock contextRef="C000252148_ClassMember" id="ixv-3249">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;Key Fund Statistics&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(as of June 30, 2026)&lt;/span&gt;&lt;/div&gt;
&lt;div&gt;&lt;span style="font-size:11px;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="1" style="border-collapse:separate;border-style:none;margin:auto;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:63%; " valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:bold;"&gt;KEY FACTS&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fund Size&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;17,845,254,941&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Number of Holdings&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;49&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Portfolio Turnover&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;33&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:AddlFundStatisticsTextBlock>
    <us-gaap:AssetsNet
      contextRef="C000252148_InstantMember"
      decimals="0"
      id="ixv-118438"
      unitRef="usd">17845254941</us-gaap:AssetsNet>
    <oef:HoldingsCount
      contextRef="C000252148_InstantMember"
      decimals="INF"
      id="ixv-118439"
      unitRef="holding">49</oef:HoldingsCount>
    <us-gaap:InvestmentCompanyPortfolioTurnover
      contextRef="C000252148_ClassMember"
      decimals="INF"
      id="ixv-118440"
      unitRef="pure">0.33</us-gaap:InvestmentCompanyPortfolioTurnover>
    <oef:HoldingsTableTextBlock contextRef="C000252148_ClassMember" id="ixv-3309">
&#160;
COUPON DISTRIBUTION 
(% of Fund's net assets)


0.01 - 0.99%

34.7

&#160;


1 - 1.99%

47.3

&#160;


2 - 2.99%

14.5

&#160;


3 - 3.99%

2.9

&#160;




&#160;
&#160;
&#160;
U.S. Treasury Obligations

99.4


Short-Term Investments and Net Other Assets (Liabilities)

0.6




ASSET ALLOCATION (% of Fund's net assets)


&#160;



&#160;

U.S. Treasury Obligations - 99.4&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Short-Term Investments and Net Other Assets (Liabilities) - 0.6


&#160;






</oef:HoldingsTableTextBlock>
    <oef:PctOfNav
      contextRef="C000252148_CD_0_Member"
      decimals="INF"
      id="ixv-118441"
      unitRef="pure">0.347</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000252148_CD_1_Member"
      decimals="INF"
      id="ixv-118442"
      unitRef="pure">0.473</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000252148_CD_2_Member"
      decimals="INF"
      id="ixv-118443"
      unitRef="pure">0.145</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000252148_CD_3_Member"
      decimals="INF"
      id="ixv-118444"
      unitRef="pure">0.029</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000252148_AA_USTreasuryObligations_Member"
      decimals="INF"
      id="ixv-118445"
      unitRef="pure">0.994</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000252148_AA_ShortTermInvestmentsandNetOtherAssetsLiabilities_Member"
      decimals="INF"
      id="ixv-118446"
      unitRef="pure">0.006</oef:PctOfNav>
    <oef:LargestHoldingsTableTextBlock contextRef="C000252148_ClassMember" id="ixv-3418">TOP HOLDINGS(% of Fund's net assets)

&#160;

&#160;


US Treasury Notes

79.5


&#160;


US Treasury Bonds

19.9


&#160;


&#160;

99.4

&#160;



</oef:LargestHoldingsTableTextBlock>
    <oef:PctOfNav
      contextRef="C000252148_TH_0_Member"
      decimals="INF"
      id="ixv-118447"
      unitRef="pure">0.795</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000252148_TH_1_Member"
      decimals="INF"
      id="ixv-118448"
      unitRef="pure">0.199</oef:PctOfNav>
    <dei:DocumentPeriodEndDate contextRef="Trust" id="ixv-3509">2026-06-30</dei:DocumentPeriodEndDate>
    <oef:FundName contextRef="C000264609_ClassMember" id="ixv-3521">Fidelity&#xae; SAI 0-5 Year Inflation-Protected Bond Index Fund</oef:FundName>
    <oef:ClassName contextRef="C000264609_ClassMember" id="ixv-3524">Fidelity&#xae; SAI 0-5 Year Inflation-Protected Bond Index Fund</oef:ClassName>
    <dei:TradingSymbol contextRef="C000264609_ClassMember" id="ixv-3528">FFNYX</dei:TradingSymbol>
    <oef:AnnlOrSemiAnnlStatementTextBlock contextRef="C000264609_ClassMember" id="ixv-3547">This semi-annual shareholder report contains information about Fidelity&#xae; SAI 0-5 Year Inflation-Protected Bond Index Fund for the period January 1, 2026 to June 30, 2026.</oef:AnnlOrSemiAnnlStatementTextBlock>
    <oef:ShareholderReportAnnualOrSemiAnnual contextRef="C000264609_ClassMember" id="ixv-3549">semi-annual shareholder report</oef:ShareholderReportAnnualOrSemiAnnual>
    <oef:AddlInfoTextBlock contextRef="C000264609_ClassMember" id="ixv-3554">You can find additional information about the Fund at fundresearch.fidelity.com/prospectus/sec. You can also request this information by contacting us at 1-800-544-3455 or by sending an e-mail to fidfunddocuments@fidelity.com.</oef:AddlInfoTextBlock>
    <oef:AddlInfoWebsite contextRef="C000264609_ClassMember" id="ixv-3556">fundresearch.fidelity.com/prospectus/sec</oef:AddlInfoWebsite>
    <oef:AddlInfoPhoneNumber contextRef="C000264609_ClassMember" id="ixv-3559">1-800-544-3455</oef:AddlInfoPhoneNumber>
    <oef:AddlInfoEmail contextRef="C000264609_ClassMember" id="ixv-3562">fidfunddocuments@fidelity.com</oef:AddlInfoEmail>
    <oef:ExpensesTextBlock contextRef="C000264609_ClassMember" id="ixv-3569">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;What were your Fund costs for the last six months?&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(based on hypothetical $10,000 investment)&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="0" style="border-collapse:collapse;border-style:none;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:51%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs of a $10,000 investment&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; background-color:#dfe0e4;border:1px solid #dfe0e4;padding:0px 0px 0px 0px;" valign="bottom"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;Costs paid as a percentage of a $10,000 investment &lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:51%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fidelity&#xae; SAI 0-5 Year Inflation-Protected Bond Index Fund&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:21%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;3&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:27%; border-bottom:1px solid #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:center;text-align-last:auto;"&gt;0.05&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:1%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:ExpensesTextBlock>
    <oef:ExpensesPaidAmt
      contextRef="C000264609_ClassMember"
      decimals="0"
      id="ixv-118449"
      unitRef="usd">3</oef:ExpensesPaidAmt>
    <oef:ExpenseRatioPct
      contextRef="C000264609_ClassMember"
      decimals="INF"
      id="ixv-118450"
      unitRef="pure">0.0005</oef:ExpenseRatioPct>
    <oef:AddlFundStatisticsTextBlock contextRef="C000264609_ClassMember" id="ixv-3610">&lt;span style="font-family:'Fidelity Sans';font-size:16px;color:#368627;font-style:normal;font-weight:bold;"&gt;Key Fund Statistics&lt;/span&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;(as of June 30, 2026)&lt;/span&gt;&lt;/div&gt;
&lt;div&gt;&lt;span style="font-size:11px;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;table cellpadding="0" cellspacing="1" style="border-collapse:separate;border-style:none;margin:auto;" width="100%"&gt;&lt;tr&gt;&lt;td style="width:63%; " valign="top"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:12px;color:#000000;font-style:normal;font-weight:bold;"&gt;KEY FACTS&lt;/span&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:bold;"&gt;&#160;&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:12px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Fund Size&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;$&lt;/span&gt;522,074,062&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Number of Holdings&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;26&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;tr&gt;&lt;td style="width:63%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;Portfolio Turnover&lt;/span&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:32%; border-bottom:1px dashed #000000;padding:0px 0px 0px 0px;" valign="middle"&gt;&lt;div style="text-align:right;text-align-last:auto;"&gt;45&lt;span style="font-family:'Fidelity Sans';font-size:11px;color:#000000;font-style:normal;font-weight:normal;"&gt;%&lt;/span&gt;&lt;/div&gt;
&lt;div style="text-align:right;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;td style="width:5%; " valign="top"&gt;&lt;span style="line-height:11px;"&gt;&#160;&lt;/span&gt;&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;
&lt;/td&gt;
&lt;/tr&gt;
&lt;/table&gt;
&lt;/div&gt;
&lt;div style="text-align:left;text-align-last:auto;"&gt;&lt;/div&gt;</oef:AddlFundStatisticsTextBlock>
    <us-gaap:AssetsNet
      contextRef="C000264609_InstantMember"
      decimals="0"
      id="ixv-118451"
      unitRef="usd">522074062</us-gaap:AssetsNet>
    <oef:HoldingsCount
      contextRef="C000264609_InstantMember"
      decimals="INF"
      id="ixv-118452"
      unitRef="holding">26</oef:HoldingsCount>
    <us-gaap:InvestmentCompanyPortfolioTurnover
      contextRef="C000264609_ClassMember"
      decimals="INF"
      id="ixv-118453"
      unitRef="pure">0.45</us-gaap:InvestmentCompanyPortfolioTurnover>
    <oef:HoldingsTableTextBlock contextRef="C000264609_ClassMember" id="ixv-3670">
&#160;
COUPON DISTRIBUTION 
(% of Fund's net assets)


0.01 - 0.99%

48.3

&#160;


1 - 1.99%

32.8

&#160;


2 - 2.99%

14.5

&#160;


3 - 3.99%

3.8

&#160;




&#160;
&#160;
&#160;
U.S. Treasury Obligations

99.4


Short-Term Investments and Net Other Assets (Liabilities)

0.6




ASSET ALLOCATION (% of Fund's net assets)


&#160;



&#160;

U.S. Treasury Obligations - 99.4&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;


&#160;

Short-Term Investments and Net Other Assets (Liabilities) - 0.6


&#160;






</oef:HoldingsTableTextBlock>
    <oef:PctOfNav
      contextRef="C000264609_CD_0_Member"
      decimals="INF"
      id="ixv-118454"
      unitRef="pure">0.483</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000264609_CD_1_Member"
      decimals="INF"
      id="ixv-118455"
      unitRef="pure">0.328</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000264609_CD_2_Member"
      decimals="INF"
      id="ixv-118456"
      unitRef="pure">0.145</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000264609_CD_3_Member"
      decimals="INF"
      id="ixv-118457"
      unitRef="pure">0.038</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000264609_AA_USTreasuryObligations_Member"
      decimals="INF"
      id="ixv-118458"
      unitRef="pure">0.994</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000264609_AA_ShortTermInvestmentsandNetOtherAssetsLiabilities_Member"
      decimals="INF"
      id="ixv-118459"
      unitRef="pure">0.006</oef:PctOfNav>
    <oef:LargestHoldingsTableTextBlock contextRef="C000264609_ClassMember" id="ixv-3779">TOP HOLDINGS(% of Fund's net assets)

&#160;

&#160;


US Treasury Notes

88.6


&#160;


US Treasury Bonds

10.8


&#160;


&#160;

99.4

&#160;



</oef:LargestHoldingsTableTextBlock>
    <oef:PctOfNav
      contextRef="C000264609_TH_0_Member"
      decimals="INF"
      id="ixv-118460"
      unitRef="pure">0.886</oef:PctOfNav>
    <oef:PctOfNav
      contextRef="C000264609_TH_1_Member"
      decimals="INF"
      id="ixv-118461"
      unitRef="pure">0.108</oef:PctOfNav>
</xbrl>
