v3.26.3
Shareholder Report, Holdings (Details)
Aug. 31, 2026
Fidelity Sustainable Low Duration Bond Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.90%
Fidelity Sustainable Low Duration Bond Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.40%
Fidelity Sustainable Low Duration Bond Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Sustainable Low Duration Bond Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Sustainable Low Duration Bond Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
Fidelity Sustainable Low Duration Bond Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Sustainable Low Duration Bond Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Sustainable Low Duration Bond Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Sustainable Low Duration Bond Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Sustainable Low Duration Bond Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Sustainable Low Duration Bond Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.30%
Fidelity Sustainable Low Duration Bond Fund | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 16.50%
Fidelity Sustainable Low Duration Bond Fund | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.60%
Fidelity Sustainable Low Duration Bond Fund | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 29.10%
Fidelity Sustainable Low Duration Bond Fund | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 15.50%
Fidelity Sustainable Low Duration Bond Fund | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Sustainable Low Duration Bond Fund | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.10%
Fidelity Sustainable Low Duration Bond Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Sustainable Low Duration Bond Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 79.40%
Fidelity Sustainable Low Duration Bond Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
Fidelity Sustainable Low Duration Bond Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 4.30%
Fidelity Sustainable Low Duration Bond Fund | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
Fidelity Sustainable Low Duration Bond Fund | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Sustainable Low Duration Bond Fund | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Sustainable Low Duration Bond Fund | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Sustainable Low Duration Bond Fund | France  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Sustainable Low Duration Bond Fund | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Sustainable Low Duration Bond Fund | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Sustainable Low Duration Bond Fund | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 46.90%
Fidelity Sustainable Low Duration Bond Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.30%
Fidelity Sustainable Low Duration Bond Fund | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.30%
Fidelity Sustainable Low Duration Bond Fund | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Sustainable Low Duration Bond Fund | AAOtherInvestmentsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Sustainable Low Duration Bond Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.40%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 16.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 29.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 15.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | United States  
Holdings [Line Items]  
Percent of Net Asset Value 79.40%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 4.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | France  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 46.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | AAOtherInvestmentsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class Z | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.40%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 16.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 29.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 15.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | United States  
Holdings [Line Items]  
Percent of Net Asset Value 79.40%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 4.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | France  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 46.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | AAOtherInvestmentsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class M | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.40%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 16.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 29.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 15.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | United States  
Holdings [Line Items]  
Percent of Net Asset Value 79.40%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 4.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | France  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 46.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | AAOtherInvestmentsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class I | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.40%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 16.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 29.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 15.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | United States  
Holdings [Line Items]  
Percent of Net Asset Value 79.40%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 4.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | France  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 46.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | AAOtherInvestmentsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class C | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 15.40%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 16.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 29.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 15.50%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.10%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | United States  
Holdings [Line Items]  
Percent of Net Asset Value 79.40%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 4.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | France  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 46.90%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | AAOtherInvestmentsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Advisor Sustainable Low Duration Bond Fund - Class A | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Sustainable Core Plus Bond Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 28.00%
Fidelity Sustainable Core Plus Bond Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 11.80%
Fidelity Sustainable Core Plus Bond Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
Fidelity Sustainable Core Plus Bond Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
Fidelity Sustainable Core Plus Bond Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
Fidelity Sustainable Core Plus Bond Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
Fidelity Sustainable Core Plus Bond Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Sustainable Core Plus Bond Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Sustainable Core Plus Bond Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Sustainable Core Plus Bond Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Sustainable Core Plus Bond Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 56.90%
Fidelity Sustainable Core Plus Bond Fund | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 5.20%
Fidelity Sustainable Core Plus Bond Fund | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Sustainable Core Plus Bond Fund | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.20%
Fidelity Sustainable Core Plus Bond Fund | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 13.80%
Fidelity Sustainable Core Plus Bond Fund | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Sustainable Core Plus Bond Fund | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
Fidelity Sustainable Core Plus Bond Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Sustainable Core Plus Bond Fund | QDBMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
Fidelity Sustainable Core Plus Bond Fund | QDCCCCCCMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Sustainable Core Plus Bond Fund | QDEquitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Sustainable Core Plus Bond Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 83.50%
Fidelity Sustainable Core Plus Bond Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Sustainable Core Plus Bond Fund | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
Fidelity Sustainable Core Plus Bond Fund | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Sustainable Core Plus Bond Fund | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Sustainable Core Plus Bond Fund | France  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Sustainable Core Plus Bond Fund | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Sustainable Core Plus Bond Fund | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Sustainable Core Plus Bond Fund | BailiwickOfJerseyMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity Sustainable Core Plus Bond Fund | Italy  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Sustainable Core Plus Bond Fund | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.70%
Fidelity Sustainable Core Plus Bond Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 39.80%
Fidelity Sustainable Core Plus Bond Fund | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 6.70%
Fidelity Sustainable Core Plus Bond Fund | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Sustainable Core Plus Bond Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Sustainable Core Plus Bond Fund | AAUSGovernmentAgencyMortgageSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 17.10%
Fidelity Sustainable Core Plus Bond Fund | AABankLoanObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Sustainable Core Plus Bond Fund | AAForeignGovernmentandGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Sustainable Core Plus Bond Fund | AAPreferredSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Sustainable Core Plus Bond Fund | AAPreferredStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Sustainable Core Plus Bond Fund | AACommonStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 28.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 11.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 56.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 5.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 13.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | QDBMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | QDCCCCCCMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | QDEquitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | United States  
Holdings [Line Items]  
Percent of Net Asset Value 83.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | France  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | BailiwickOfJerseyMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | Italy  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 39.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 6.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | AAUSGovernmentAgencyMortgageSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 17.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | AABankLoanObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | AAForeignGovernmentandGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | AAPreferredSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | AAPreferredStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class Z | AACommonStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 28.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 11.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 56.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 5.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 13.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | QDBMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | QDCCCCCCMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | QDEquitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | United States  
Holdings [Line Items]  
Percent of Net Asset Value 83.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | France  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | BailiwickOfJerseyMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | Italy  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 39.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 6.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | AAUSGovernmentAgencyMortgageSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 17.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | AABankLoanObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | AAForeignGovernmentandGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | AAPreferredSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | AAPreferredStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class M | AACommonStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 28.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 11.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 56.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 5.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 13.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | QDBMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | QDCCCCCCMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | QDEquitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | United States  
Holdings [Line Items]  
Percent of Net Asset Value 83.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | France  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | BailiwickOfJerseyMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | Italy  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 39.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 6.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | AAUSGovernmentAgencyMortgageSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 17.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | AABankLoanObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | AAForeignGovernmentandGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | AAPreferredSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | AAPreferredStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class I | AACommonStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 28.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 11.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 56.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 5.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 13.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | QDBMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | QDCCCCCCMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | QDEquitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | United States  
Holdings [Line Items]  
Percent of Net Asset Value 83.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | France  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | BailiwickOfJerseyMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | Italy  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 39.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 6.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | AAUSGovernmentAgencyMortgageSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 17.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | AABankLoanObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | AAForeignGovernmentandGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | AAPreferredSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | AAPreferredStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class C | AACommonStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 28.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 11.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 56.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 5.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.20%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 13.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | QDBMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | QDCCCCCCMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | QDEquitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | United States  
Holdings [Line Items]  
Percent of Net Asset Value 83.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | France  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | BailiwickOfJerseyMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | Italy  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 39.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 6.70%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | AAUSGovernmentAgencyMortgageSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 17.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | AABankLoanObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | AAForeignGovernmentandGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | AAPreferredSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | AAPreferredStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Advisor Sustainable Core Plus Bond Fund - Class A | AACommonStocksMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Sustainability Bond Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 35.30%
Fidelity Sustainability Bond Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 10.00%
Fidelity Sustainability Bond Index Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 8.90%
Fidelity Sustainability Bond Index Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 7.40%
Fidelity Sustainability Bond Index Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
Fidelity Sustainability Bond Index Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity Sustainability Bond Index Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Sustainability Bond Index Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Sustainability Bond Index Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Sustainability Bond Index Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Sustainability Bond Index Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 68.50%
Fidelity Sustainability Bond Index Fund | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
Fidelity Sustainability Bond Index Fund | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Sustainability Bond Index Fund | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 13.30%
Fidelity Sustainability Bond Index Fund | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 11.00%
Fidelity Sustainability Bond Index Fund | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Sustainability Bond Index Fund | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
Fidelity Sustainability Bond Index Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 92.20%
Fidelity Sustainability Bond Index Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity Sustainability Bond Index Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity Sustainability Bond Index Fund | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Sustainability Bond Index Fund | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Sustainability Bond Index Fund | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Sustainability Bond Index Fund | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Sustainability Bond Index Fund | MultinationalMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Sustainability Bond Index Fund | Mexico  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
Fidelity Sustainability Bond Index Fund | Israel  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Sustainability Bond Index Fund | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 27.60%
Fidelity Sustainability Bond Index Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 45.30%
Fidelity Sustainability Bond Index Fund | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Sustainability Bond Index Fund | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Sustainability Bond Index Fund | AAOtherInvestmentsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity Sustainability Bond Index Fund | AAUSGovernmentAgencyMortgageSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 23.10%
Fidelity Sustainability Bond Index Fund | AAForeignGovernmentandGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.20%
Fidelity Sustainability Bond Index Fund | AAUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Short-Term Bond Index Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 72.80%
Fidelity Short-Term Bond Index Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Short-Term Bond Index Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Short-Term Bond Index Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Short-Term Bond Index Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Short-Term Bond Index Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
Fidelity Short-Term Bond Index Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Short-Term Bond Index Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Short-Term Bond Index Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Short-Term Bond Index Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Short-Term Bond Index Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 73.10%
Fidelity Short-Term Bond Index Fund | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Short-Term Bond Index Fund | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.40%
Fidelity Short-Term Bond Index Fund | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 12.30%
Fidelity Short-Term Bond Index Fund | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 10.80%
Fidelity Short-Term Bond Index Fund | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Short-Term Bond Index Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 93.80%
Fidelity Short-Term Bond Index Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity Short-Term Bond Index Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity Short-Term Bond Index Fund | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity Short-Term Bond Index Fund | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
Fidelity Short-Term Bond Index Fund | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity Short-Term Bond Index Fund | MultinationalMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Short-Term Bond Index Fund | Spain  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Short-Term Bond Index Fund | Australia  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Short-Term Bond Index Fund | Korea, Republic of  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity Short-Term Bond Index Fund | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 26.50%
Fidelity Short-Term Bond Index Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 72.80%
Fidelity Short-Term Bond Index Fund | AAOtherInvestmentsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
Fidelity Short-Term Bond Index Fund | AAForeignGovernmentandGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Short-Term Bond Index Fund | AAUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Short-Term Bond Index Fund | AAMunicipalSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity Series Sustainable Investment Grade Bond Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 36.60%
Fidelity Series Sustainable Investment Grade Bond Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 12.80%
Fidelity Series Sustainable Investment Grade Bond Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 5.50%
Fidelity Series Sustainable Investment Grade Bond Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
Fidelity Series Sustainable Investment Grade Bond Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.10%
Fidelity Series Sustainable Investment Grade Bond Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
Fidelity Series Sustainable Investment Grade Bond Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Series Sustainable Investment Grade Bond Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Series Sustainable Investment Grade Bond Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity Series Sustainable Investment Grade Bond Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Series Sustainable Investment Grade Bond Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 65.70%
Fidelity Series Sustainable Investment Grade Bond Fund | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
Fidelity Series Sustainable Investment Grade Bond Fund | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Series Sustainable Investment Grade Bond Fund | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 11.60%
Fidelity Series Sustainable Investment Grade Bond Fund | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 10.30%
Fidelity Series Sustainable Investment Grade Bond Fund | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Series Sustainable Investment Grade Bond Fund | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.30%
Fidelity Series Sustainable Investment Grade Bond Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
Fidelity Series Sustainable Investment Grade Bond Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 92.90%
Fidelity Series Sustainable Investment Grade Bond Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Series Sustainable Investment Grade Bond Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity Series Sustainable Investment Grade Bond Fund | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.70%
Fidelity Series Sustainable Investment Grade Bond Fund | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity Series Sustainable Investment Grade Bond Fund | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity Series Sustainable Investment Grade Bond Fund | BailiwickOfJerseyMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Series Sustainable Investment Grade Bond Fund | Mexico  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Series Sustainable Investment Grade Bond Fund | Australia  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity Series Sustainable Investment Grade Bond Fund | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 22.30%
Fidelity Series Sustainable Investment Grade Bond Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 49.40%
Fidelity Series Sustainable Investment Grade Bond Fund | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 6.30%
Fidelity Series Sustainable Investment Grade Bond Fund | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
Fidelity Series Sustainable Investment Grade Bond Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
Fidelity Series Sustainable Investment Grade Bond Fund | AAUSGovernmentAgencyMortgageSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 16.30%
Fidelity Series Sustainable Investment Grade Bond Fund | AAForeignGovernmentandGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
Fidelity Series Corporate Bond Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.90%
Fidelity Series Corporate Bond Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.80%
Fidelity Series Corporate Bond Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Series Corporate Bond Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
Fidelity Series Corporate Bond Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
Fidelity Series Corporate Bond Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Series Corporate Bond Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
Fidelity Series Corporate Bond Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity Series Corporate Bond Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Series Corporate Bond Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity Series Corporate Bond Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.90%
Fidelity Series Corporate Bond Fund | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity Series Corporate Bond Fund | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
Fidelity Series Corporate Bond Fund | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 28.90%
Fidelity Series Corporate Bond Fund | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 52.80%
Fidelity Series Corporate Bond Fund | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%
Fidelity Series Corporate Bond Fund | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Series Corporate Bond Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
Fidelity Series Corporate Bond Fund | QDBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Series Corporate Bond Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 84.60%
Fidelity Series Corporate Bond Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 2.60%
Fidelity Series Corporate Bond Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 4.00%
Fidelity Series Corporate Bond Fund | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Series Corporate Bond Fund | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Series Corporate Bond Fund | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Series Corporate Bond Fund | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.50%
Fidelity Series Corporate Bond Fund | Australia  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Series Corporate Bond Fund | Ireland  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Series Corporate Bond Fund | Belgium  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Series Corporate Bond Fund | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 88.70%
Fidelity Series Corporate Bond Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.90%
Fidelity Series Corporate Bond Fund | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Series Corporate Bond Fund | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Series Corporate Bond Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
Fidelity Series Corporate Bond Fund | AAForeignGovernmentandGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Series Corporate Bond Fund | AAPreferredSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity SAI Sustainable Low Duration Bond Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 21.40%
Fidelity SAI Sustainable Low Duration Bond Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 12.90%
Fidelity SAI Sustainable Low Duration Bond Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity SAI Sustainable Low Duration Bond Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity SAI Sustainable Low Duration Bond Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity SAI Sustainable Low Duration Bond Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
Fidelity SAI Sustainable Low Duration Bond Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity SAI Sustainable Low Duration Bond Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity SAI Sustainable Low Duration Bond Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity SAI Sustainable Low Duration Bond Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity SAI Sustainable Low Duration Bond Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 34.30%
Fidelity SAI Sustainable Low Duration Bond Fund | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 14.40%
Fidelity SAI Sustainable Low Duration Bond Fund | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
Fidelity SAI Sustainable Low Duration Bond Fund | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 28.70%
Fidelity SAI Sustainable Low Duration Bond Fund | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 17.00%
Fidelity SAI Sustainable Low Duration Bond Fund | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity SAI Sustainable Low Duration Bond Fund | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.10%
Fidelity SAI Sustainable Low Duration Bond Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity SAI Sustainable Low Duration Bond Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 79.60%
Fidelity SAI Sustainable Low Duration Bond Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 5.50%
Fidelity SAI Sustainable Low Duration Bond Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 4.30%
Fidelity SAI Sustainable Low Duration Bond Fund | GrandCaymanUKOverseasTerMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.40%
Fidelity SAI Sustainable Low Duration Bond Fund | Japan  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
Fidelity SAI Sustainable Low Duration Bond Fund | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity SAI Sustainable Low Duration Bond Fund | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity SAI Sustainable Low Duration Bond Fund | France  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity SAI Sustainable Low Duration Bond Fund | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 0.90%
Fidelity SAI Sustainable Low Duration Bond Fund | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 2.10%
Fidelity SAI Sustainable Low Duration Bond Fund | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 47.70%
Fidelity SAI Sustainable Low Duration Bond Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 34.30%
Fidelity SAI Sustainable Low Duration Bond Fund | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 15.80%
Fidelity SAI Sustainable Low Duration Bond Fund | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity SAI Sustainable Low Duration Bond Fund | AAOtherInvestmentsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity SAI Sustainable Low Duration Bond Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
Fidelity SAI Investment Grade Securitized Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 31.10%
Fidelity SAI Investment Grade Securitized Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 18.60%
Fidelity SAI Investment Grade Securitized Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 18.30%
Fidelity SAI Investment Grade Securitized Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 13.30%
Fidelity SAI Investment Grade Securitized Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 9.20%
Fidelity SAI Investment Grade Securitized Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.30%
Fidelity SAI Investment Grade Securitized Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 4.00%
Fidelity SAI Investment Grade Securitized Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
Fidelity SAI Investment Grade Securitized Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity SAI Investment Grade Securitized Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity SAI Investment Grade Securitized Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 86.20%
Fidelity SAI Investment Grade Securitized Fund | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 8.90%
Fidelity SAI Investment Grade Securitized Fund | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
Fidelity SAI Investment Grade Securitized Fund | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity SAI Investment Grade Securitized Fund | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity SAI Investment Grade Securitized Fund | QDBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
Fidelity SAI Investment Grade Securitized Fund | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 26.00%
Fidelity SAI Investment Grade Securitized Fund | QDBMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity SAI Investment Grade Securitized Fund | QDCCCCCCMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity SAI Investment Grade Securitized Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 100.00%
Fidelity SAI Investment Grade Securitized Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
Fidelity SAI Investment Grade Securitized Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 4.80%
Fidelity SAI Investment Grade Securitized Fund | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
Fidelity SAI Investment Grade Securitized Fund | AACMOsandOtherMortgageRelatedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 31.80%
Fidelity SAI Investment Grade Securitized Fund | AAUSGovernmentAgencyMortgageSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 81.40%
Fidelity SAI Investment Grade Securitized Fund | AAOptionsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
Fidelity Conservative Income Bond Fund | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 12.80%
Fidelity Conservative Income Bond Fund | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 12.00%
Fidelity Conservative Income Bond Fund | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Conservative Income Bond Fund | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
Fidelity Conservative Income Bond Fund | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Conservative Income Bond Fund | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Conservative Income Bond Fund | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Conservative Income Bond Fund | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity Conservative Income Bond Fund | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Conservative Income Bond Fund | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Conservative Income Bond Fund | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 24.80%
Fidelity Conservative Income Bond Fund | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 13.80%
Fidelity Conservative Income Bond Fund | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 5.50%
Fidelity Conservative Income Bond Fund | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 29.70%
Fidelity Conservative Income Bond Fund | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
Fidelity Conservative Income Bond Fund | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Conservative Income Bond Fund | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.00%
Fidelity Conservative Income Bond Fund | United States  
Holdings [Line Items]  
Percent of Net Asset Value 83.50%
Fidelity Conservative Income Bond Fund | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
Fidelity Conservative Income Bond Fund | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 3.70%
Fidelity Conservative Income Bond Fund | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Conservative Income Bond Fund | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Conservative Income Bond Fund | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
Fidelity Conservative Income Bond Fund | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Conservative Income Bond Fund | Australia  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Conservative Income Bond Fund | Ireland  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Conservative Income Bond Fund | Denmark  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Conservative Income Bond Fund | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 42.30%
Fidelity Conservative Income Bond Fund | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 24.80%
Fidelity Conservative Income Bond Fund | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 14.50%
Fidelity Conservative Income Bond Fund | AAOtherInvestmentsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Conservative Income Bond Fund | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.00%
Fidelity Advisor Conservative Income Bond Fund - Class Z | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 12.80%
Fidelity Advisor Conservative Income Bond Fund - Class Z | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 12.00%
Fidelity Advisor Conservative Income Bond Fund - Class Z | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Conservative Income Bond Fund - Class Z | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
Fidelity Advisor Conservative Income Bond Fund - Class Z | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Advisor Conservative Income Bond Fund - Class Z | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Conservative Income Bond Fund - Class Z | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Conservative Income Bond Fund - Class Z | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity Advisor Conservative Income Bond Fund - Class Z | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Conservative Income Bond Fund - Class Z | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Conservative Income Bond Fund - Class Z | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 24.80%
Fidelity Advisor Conservative Income Bond Fund - Class Z | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 13.80%
Fidelity Advisor Conservative Income Bond Fund - Class Z | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 5.50%
Fidelity Advisor Conservative Income Bond Fund - Class Z | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 29.70%
Fidelity Advisor Conservative Income Bond Fund - Class Z | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
Fidelity Advisor Conservative Income Bond Fund - Class Z | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Conservative Income Bond Fund - Class Z | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.00%
Fidelity Advisor Conservative Income Bond Fund - Class Z | United States  
Holdings [Line Items]  
Percent of Net Asset Value 83.50%
Fidelity Advisor Conservative Income Bond Fund - Class Z | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
Fidelity Advisor Conservative Income Bond Fund - Class Z | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 3.70%
Fidelity Advisor Conservative Income Bond Fund - Class Z | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Conservative Income Bond Fund - Class Z | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Conservative Income Bond Fund - Class Z | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
Fidelity Advisor Conservative Income Bond Fund - Class Z | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Conservative Income Bond Fund - Class Z | Australia  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Conservative Income Bond Fund - Class Z | Ireland  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Conservative Income Bond Fund - Class Z | Denmark  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Conservative Income Bond Fund - Class Z | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 42.30%
Fidelity Advisor Conservative Income Bond Fund - Class Z | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 24.80%
Fidelity Advisor Conservative Income Bond Fund - Class Z | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 14.50%
Fidelity Advisor Conservative Income Bond Fund - Class Z | AAOtherInvestmentsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Advisor Conservative Income Bond Fund - Class Z | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.00%
Fidelity Advisor Conservative Income Bond Fund - Class I | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 12.80%
Fidelity Advisor Conservative Income Bond Fund - Class I | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 12.00%
Fidelity Advisor Conservative Income Bond Fund - Class I | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Conservative Income Bond Fund - Class I | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
Fidelity Advisor Conservative Income Bond Fund - Class I | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Advisor Conservative Income Bond Fund - Class I | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Conservative Income Bond Fund - Class I | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Conservative Income Bond Fund - Class I | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity Advisor Conservative Income Bond Fund - Class I | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Conservative Income Bond Fund - Class I | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Conservative Income Bond Fund - Class I | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 24.80%
Fidelity Advisor Conservative Income Bond Fund - Class I | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 13.80%
Fidelity Advisor Conservative Income Bond Fund - Class I | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 5.50%
Fidelity Advisor Conservative Income Bond Fund - Class I | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 29.70%
Fidelity Advisor Conservative Income Bond Fund - Class I | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
Fidelity Advisor Conservative Income Bond Fund - Class I | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Conservative Income Bond Fund - Class I | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.00%
Fidelity Advisor Conservative Income Bond Fund - Class I | United States  
Holdings [Line Items]  
Percent of Net Asset Value 83.50%
Fidelity Advisor Conservative Income Bond Fund - Class I | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
Fidelity Advisor Conservative Income Bond Fund - Class I | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 3.70%
Fidelity Advisor Conservative Income Bond Fund - Class I | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Conservative Income Bond Fund - Class I | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Conservative Income Bond Fund - Class I | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
Fidelity Advisor Conservative Income Bond Fund - Class I | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Conservative Income Bond Fund - Class I | Australia  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Conservative Income Bond Fund - Class I | Ireland  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Conservative Income Bond Fund - Class I | Denmark  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Conservative Income Bond Fund - Class I | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 42.30%
Fidelity Advisor Conservative Income Bond Fund - Class I | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 24.80%
Fidelity Advisor Conservative Income Bond Fund - Class I | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 14.50%
Fidelity Advisor Conservative Income Bond Fund - Class I | AAOtherInvestmentsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Advisor Conservative Income Bond Fund - Class I | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.00%
Fidelity Advisor Conservative Income Bond Fund - Class A | TH0Member  
Holdings [Line Items]  
Percent of Net Asset Value 12.80%
Fidelity Advisor Conservative Income Bond Fund - Class A | TH1Member  
Holdings [Line Items]  
Percent of Net Asset Value 12.00%
Fidelity Advisor Conservative Income Bond Fund - Class A | TH2Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
Fidelity Advisor Conservative Income Bond Fund - Class A | TH3Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
Fidelity Advisor Conservative Income Bond Fund - Class A | TH4Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
Fidelity Advisor Conservative Income Bond Fund - Class A | TH5Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Conservative Income Bond Fund - Class A | TH6Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
Fidelity Advisor Conservative Income Bond Fund - Class A | TH7Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
Fidelity Advisor Conservative Income Bond Fund - Class A | TH8Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Conservative Income Bond Fund - Class A | TH9Member  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
Fidelity Advisor Conservative Income Bond Fund - Class A | QDUSGovernmentandUSGovernmentAgencyObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 24.80%
Fidelity Advisor Conservative Income Bond Fund - Class A | QDAAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 13.80%
Fidelity Advisor Conservative Income Bond Fund - Class A | QDAAMember  
Holdings [Line Items]  
Percent of Net Asset Value 5.50%
Fidelity Advisor Conservative Income Bond Fund - Class A | QDAMember  
Holdings [Line Items]  
Percent of Net Asset Value 29.70%
Fidelity Advisor Conservative Income Bond Fund - Class A | QDBBBMember  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
Fidelity Advisor Conservative Income Bond Fund - Class A | QDNotRatedMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
Fidelity Advisor Conservative Income Bond Fund - Class A | QDShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.00%
Fidelity Advisor Conservative Income Bond Fund - Class A | United States  
Holdings [Line Items]  
Percent of Net Asset Value 83.50%
Fidelity Advisor Conservative Income Bond Fund - Class A | Canada  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
Fidelity Advisor Conservative Income Bond Fund - Class A | United Kingdom  
Holdings [Line Items]  
Percent of Net Asset Value 3.70%
Fidelity Advisor Conservative Income Bond Fund - Class A | Switzerland  
Holdings [Line Items]  
Percent of Net Asset Value 0.80%
Fidelity Advisor Conservative Income Bond Fund - Class A | Netherlands  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Conservative Income Bond Fund - Class A | Germany  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
Fidelity Advisor Conservative Income Bond Fund - Class A | OtherMember  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
Fidelity Advisor Conservative Income Bond Fund - Class A | Australia  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Conservative Income Bond Fund - Class A | Ireland  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Conservative Income Bond Fund - Class A | Denmark  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
Fidelity Advisor Conservative Income Bond Fund - Class A | AACorporateBondsMember  
Holdings [Line Items]  
Percent of Net Asset Value 42.30%
Fidelity Advisor Conservative Income Bond Fund - Class A | AAUSTreasuryObligationsMember  
Holdings [Line Items]  
Percent of Net Asset Value 24.80%
Fidelity Advisor Conservative Income Bond Fund - Class A | AAAssetBackedSecuritiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 14.50%
Fidelity Advisor Conservative Income Bond Fund - Class A | AAOtherInvestmentsMember  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
Fidelity Advisor Conservative Income Bond Fund - Class A | AAShortTermInvestmentsandNetOtherAssetsLiabilitiesMember  
Holdings [Line Items]  
Percent of Net Asset Value 18.00%