v3.26.1
Shareholder Report, Line Graph (Details) - USD ($)
12 Months Ended 48 Months Ended 60 Months Ended 108 Months Ended 132 Months Ended
Jan. 31, 2026
Jan. 31, 2026
Jan. 31, 2026
Jan. 31, 2026
Jan. 31, 2026
C000235213_0_LG_BBIndexMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span>    
C000235213_0_BBIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value $ 10,000        
C000235213_0_BBIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,467        
C000235213_0_BBIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,771        
C000235213_0_BBIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,995        
C000235213_0_BBIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,512        
C000245667_0_LG_BBIndexMember_4YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name   <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span>      
C000245667_0_BBIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000245667_0_BBIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,616        
C000245667_0_BBIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,837        
C000245667_0_BBIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,346        
C000048850_LG_ClassMember_11YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name         <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Tax-Free Bond Fund</span>
C000048850_ClassMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 25,000        
C000048850_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 24,921        
C000048850_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 26,014        
C000048850_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 26,818        
C000048850_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 29,465        
C000048850_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 30,626        
C000048850_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 30,272        
C000048850_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 28,946        
C000048850_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 30,019        
C000048850_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 30,721        
C000048850_ClassMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 32,246        
C000048850_LG_1_AdditionalIndexMember_11YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name         <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg 3+ Year Non-AMT Municipal Bond Index</span>
C000048850_1_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 25,000        
C000048850_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 24,894        
C000048850_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 25,873        
C000048850_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 26,767        
C000048850_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 29,283        
C000048850_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 30,557        
C000048850_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 29,921        
C000048850_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 28,826        
C000048850_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 29,667        
C000048850_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 30,231        
C000048850_1_AdditionalIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 31,672        
C000048850_LG_2_AdditionalIndexMember_11YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name         <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span>
C000048850_2_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 25,000        
C000048850_2_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 24,930        
C000048850_2_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 25,808        
C000048850_2_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 26,651        
C000048850_2_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 28,955        
C000048850_2_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 30,117        
C000048850_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 29,549        
C000048850_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 28,589        
C000048850_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 29,418        
C000048850_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 30,031        
C000048850_2_AdditionalIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 31,442        
C000235223_LG_ClassMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® Sustainable Intermediate Municipal Income Fund</span>    
C000235223_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235223_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,344        
C000235223_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,692        
C000235223_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,936        
C000235223_ClassMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,558        
C000235223_LG_1_AdditionalIndexMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg 3-15 Year Blend (2-17) Municipal Bond Index</span>    
C000235223_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235223_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,276        
C000235223_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,537        
C000235223_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,731        
C000235223_1_AdditionalIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,345        
C000235223_LG_2_AdditionalIndexMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span>    
C000235223_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235223_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,168        
C000235223_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,463        
C000235223_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,681        
C000235223_2_AdditionalIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,183        
C000235227_LG_ClassMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class Z</span>    
C000235227_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235227_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,349        
C000235227_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,703        
C000235227_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,954        
C000235227_ClassMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,584        
C000235227_LG_1_AdditionalIndexMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg 3-15 Year Blend (2-17) Municipal Bond Index</span>    
C000235227_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235227_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,276        
C000235227_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,537        
C000235227_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,731        
C000235227_1_AdditionalIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,345        
C000235227_LG_2_AdditionalIndexMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span>    
C000235227_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235227_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,168        
C000235227_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,463        
C000235227_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,681        
C000235227_2_AdditionalIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,183        
C000235224_LG_ClassMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class M</span>    
C000235224_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 9,600        
C000235224_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 9,911        
C000235224_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,218        
C000235224_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,425        
C000235224_ClassMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 10,981        
C000235224_LG_1_AdditionalIndexMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg 3-15 Year Blend (2-17) Municipal Bond Index</span>    
C000235224_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235224_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,276        
C000235224_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,537        
C000235224_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,731        
C000235224_1_AdditionalIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,345        
C000235224_LG_2_AdditionalIndexMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span>    
C000235224_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235224_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,168        
C000235224_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,463        
C000235224_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,681        
C000235224_2_AdditionalIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,183        
C000235226_LG_ClassMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class I</span>    
C000235226_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235226_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,344        
C000235226_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,691        
C000235226_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,935        
C000235226_ClassMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,558        
C000235226_LG_1_AdditionalIndexMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg 3-15 Year Blend (2-17) Municipal Bond Index</span>    
C000235226_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235226_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,276        
C000235226_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,537        
C000235226_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,731        
C000235226_1_AdditionalIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,345        
C000235226_LG_2_AdditionalIndexMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span>    
C000235226_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235226_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,168        
C000235226_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,463        
C000235226_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,681        
C000235226_2_AdditionalIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,183        
C000235225_LG_ClassMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class C</span>    
C000235225_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235225_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,262        
C000235225_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,508        
C000235225_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,634        
C000235225_ClassMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,118        
C000235225_LG_1_AdditionalIndexMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg 3-15 Year Blend (2-17) Municipal Bond Index</span>    
C000235225_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235225_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,276        
C000235225_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,537        
C000235225_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,731        
C000235225_1_AdditionalIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,345        
C000235225_LG_2_AdditionalIndexMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span>    
C000235225_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000235225_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,168        
C000235225_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,463        
C000235225_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,681        
C000235225_2_AdditionalIndexMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 11,183        
C000235228_LG_ClassMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Class A</span>    
C000235228_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 9,600        
C000235228_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 9,911        
C000235228_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,218        
C000235228_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,425        
C000235228_ClassMember_AsOf_2026Member          
Account Value [Line Items]          
Accumulated Value 10,981        
C000235228_LG_1_AdditionalIndexMember_5YRMember          
Account Value [Line Items]          
Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg 3-15 Year Blend (2-17) Municipal Bond Index</span>    
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Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Fidelity® SAI Sustainable Municipal Income Fund</span>    
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Line Graph and Table Measure Name     <span style="font-family:'Fidelity Sans';font-size:9px;color:#000000;font-style:normal;font-weight:normal;">Bloomberg Municipal Bond Index</span>    
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