v3.26.1
Shareholder Report, Holdings (Details)
Jun. 30, 2026
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 70.40%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 29.00%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund | CD0Member  
Holdings [Line Items]  
Percent of Net Asset Value 29.20%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund | CD1Member  
Holdings [Line Items]  
Percent of Net Asset Value 53.10%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund | CD2Member  
Holdings [Line Items]  
Percent of Net Asset Value 16.50%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund | CD3Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 99.40%
Fidelity Series 5+ Year Inflation-Protected Bond Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 88.20%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 9.40%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund | CD0Member  
Holdings [Line Items]  
Percent of Net Asset Value 45.80%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund | CD1Member  
Holdings [Line Items]  
Percent of Net Asset Value 33.50%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund | CD2Member  
Holdings [Line Items]  
Percent of Net Asset Value 14.20%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund | CD3Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.10%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 97.60%
Fidelity Series 0-5 Year Inflation-Protected Bond Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
Fidelity SAI Municipal Income Fund | TS0Member  
Holdings [Line Items]  
Percent of Net Asset Value 9.80%
Fidelity SAI Municipal Income Fund | TS1Member  
Holdings [Line Items]  
Percent of Net Asset Value 9.20%
Fidelity SAI Municipal Income Fund | TS2Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.80%
Fidelity SAI Municipal Income Fund | TS3Member  
Holdings [Line Items]  
Percent of Net Asset Value 7.60%
Fidelity SAI Municipal Income Fund | TS4Member  
Holdings [Line Items]  
Percent of Net Asset Value 6.10%
Fidelity SAI Municipal Income Fund | RS0Member  
Holdings [Line Items]  
Percent of Net Asset Value 38.50%
Fidelity SAI Municipal Income Fund | RS1Member  
Holdings [Line Items]  
Percent of Net Asset Value 19.30%
Fidelity SAI Municipal Income Fund | RS2Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.70%
Fidelity SAI Municipal Income Fund | RS3Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.30%
Fidelity SAI Municipal Income Fund | RS4Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.70%
Fidelity SAI Municipal Income Fund | RS5Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%
Fidelity SAI Municipal Income Fund | RS6Member  
Holdings [Line Items]  
Percent of Net Asset Value 11.30%
Fidelity SAI Municipal Income Fund | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 6.50%
Fidelity SAI Municipal Income Fund | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 43.60%
Fidelity SAI Municipal Income Fund | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 36.30%
Fidelity SAI Municipal Income Fund | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 5.90%
Fidelity SAI Municipal Income Fund | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity SAI Municipal Income Fund | QDBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity SAI Municipal Income Fund | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
Fidelity SAI Municipal Income Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.10%
Fidelity SAI International Credit Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.70%
Fidelity SAI International Credit Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 6.00%
Fidelity SAI International Credit Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.90%
Fidelity SAI International Credit Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
Fidelity SAI International Credit Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.10%
Fidelity SAI International Credit Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.10%
Fidelity SAI International Credit Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity SAI International Credit Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity SAI International Credit Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity SAI International Credit Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity SAI International Credit Fund | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.50%
Fidelity SAI International Credit Fund | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity SAI International Credit Fund | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 14.80%
Fidelity SAI International Credit Fund | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.50%
Fidelity SAI International Credit Fund | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.60%
Fidelity SAI International Credit Fund | QDBMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity SAI International Credit Fund | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 6.50%
Fidelity SAI International Credit Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 6.60%
Fidelity SAI International Credit Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 21.70%
Fidelity SAI International Credit Fund | QDCCCCCCMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity SAI International Credit Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 33.40%
Fidelity SAI International Credit Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 16.50%
Fidelity SAI International Credit Fund | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 12.30%
Fidelity SAI International Credit Fund | France  
Holdings [Line Items]  
Percent of Net Asset Value 5.70%
Fidelity SAI International Credit Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 5.40%
Fidelity SAI International Credit Fund | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 4.10%
Fidelity SAI International Credit Fund | MultinationalMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
Fidelity SAI International Credit Fund | Australia  
Holdings [Line Items]  
Percent of Net Asset Value 3.10%
Fidelity SAI International Credit Fund | Luxembourg  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
Fidelity SAI International Credit Fund | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.60%
Fidelity SAI International Credit Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 21.70%
Fidelity SAI International Credit Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 6.60%
Fidelity SAI International Credit Fund | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 59.00%
Fidelity SAI International Credit Fund | AAForeignGovernmentandGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 11.40%
Fidelity SAI International Credit Fund | AAPreferredSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity International Bond Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 11.50%
Fidelity International Bond Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 7.80%
Fidelity International Bond Index Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 7.20%
Fidelity International Bond Index Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 6.00%
Fidelity International Bond Index Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%
Fidelity International Bond Index Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.60%
Fidelity International Bond Index Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.50%
Fidelity International Bond Index Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity International Bond Index Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
Fidelity International Bond Index Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity International Bond Index Fund | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.90%
Fidelity International Bond Index Fund | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.30%
Fidelity International Bond Index Fund | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 22.00%
Fidelity International Bond Index Fund | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.90%
Fidelity International Bond Index Fund | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity International Bond Index Fund | QDBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity International Bond Index Fund | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 26.30%
Fidelity International Bond Index Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity International Bond Index Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 6.30%
Fidelity International Bond Index Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 8.50%
Fidelity International Bond Index Fund | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 10.10%
Fidelity International Bond Index Fund | France  
Holdings [Line Items]  
Percent of Net Asset Value 14.70%
Fidelity International Bond Index Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 8.50%
Fidelity International Bond Index Fund | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 11.90%
Fidelity International Bond Index Fund | MultinationalMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.60%
Fidelity International Bond Index Fund | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 21.10%
Fidelity International Bond Index Fund | Italy  
Holdings [Line Items]  
Percent of Net Asset Value 8.40%
Fidelity International Bond Index Fund | Spain  
Holdings [Line Items]  
Percent of Net Asset Value 5.90%
Fidelity International Bond Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity International Bond Index Fund | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 32.40%
Fidelity International Bond Index Fund | AAForeignGovernmentandGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 65.70%
Fidelity International Bond Index Fund | AAPreferredSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Inflation-Protected Bond Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 79.40%
Fidelity Inflation-Protected Bond Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 20.00%
Fidelity Inflation-Protected Bond Index Fund | CD0Member  
Holdings [Line Items]  
Percent of Net Asset Value 36.20%
Fidelity Inflation-Protected Bond Index Fund | CD1Member  
Holdings [Line Items]  
Percent of Net Asset Value 44.40%
Fidelity Inflation-Protected Bond Index Fund | CD2Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.30%
Fidelity Inflation-Protected Bond Index Fund | CD3Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Inflation-Protected Bond Index Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 99.40%
Fidelity Inflation-Protected Bond Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity SAI Inflation-Protected Bond Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 79.50%
Fidelity SAI Inflation-Protected Bond Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 19.90%
Fidelity SAI Inflation-Protected Bond Index Fund | CD0Member  
Holdings [Line Items]  
Percent of Net Asset Value 34.70%
Fidelity SAI Inflation-Protected Bond Index Fund | CD1Member  
Holdings [Line Items]  
Percent of Net Asset Value 47.30%
Fidelity SAI Inflation-Protected Bond Index Fund | CD2Member  
Holdings [Line Items]  
Percent of Net Asset Value 14.50%
Fidelity SAI Inflation-Protected Bond Index Fund | CD3Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
Fidelity SAI Inflation-Protected Bond Index Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 99.40%
Fidelity SAI Inflation-Protected Bond Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity SAI 0-5 Year Inflation-Protected Bond Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 88.60%
Fidelity SAI 0-5 Year Inflation-Protected Bond Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 10.80%
Fidelity SAI 0-5 Year Inflation-Protected Bond Index Fund | CD0Member  
Holdings [Line Items]  
Percent of Net Asset Value 48.30%
Fidelity SAI 0-5 Year Inflation-Protected Bond Index Fund | CD1Member  
Holdings [Line Items]  
Percent of Net Asset Value 32.80%
Fidelity SAI 0-5 Year Inflation-Protected Bond Index Fund | CD2Member  
Holdings [Line Items]  
Percent of Net Asset Value 14.50%
Fidelity SAI 0-5 Year Inflation-Protected Bond Index Fund | CD3Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
Fidelity SAI 0-5 Year Inflation-Protected Bond Index Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 99.40%
Fidelity SAI 0-5 Year Inflation-Protected Bond Index Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%