v3.25.3
Shareholder Report, Line Graph (Details) - USD ($)
12 Months Ended 84 Months Ended 96 Months Ended 108 Months Ended 132 Months Ended
Aug. 31, 2025
Aug. 31, 2025
Aug. 31, 2025
Aug. 31, 2025
Aug. 31, 2025
C000211071_LG_ClassMember_7YRMember          
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® Series Bond Index Fund</span>      
C000211071_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value $ 10,000        
C000211071_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 10,601        
C000211071_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 11,282        
C000211071_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,266        
C000211071_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 9,962        
C000211071_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 9,850        
C000211071_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,563        
C000211071_LG_1_AdditionalIndexMember_7YRMember          
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 U.S. Aggregate Bond Index</span>      
C000211071_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000211071_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 10,596        
C000211071_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 11,282        
C000211071_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,272        
C000211071_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 9,974        
C000211071_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 9,855        
C000211071_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 10,574        
C000177581_LG_ClassMember_9YRMember          
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 Flex® U.S. Bond Index Fund</span>  
C000177581_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000177581_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,399        
C000177581_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 10,283        
C000177581_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 11,340        
C000177581_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,077        
C000177581_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 12,042        
C000177581_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,659        
C000177581_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,528        
C000177581_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 11,287        
C000177581_LG_1_AdditionalIndexMember_9YRMember          
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 U.S. Aggregate Bond Index</span>  
C000177581_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000177581_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,410        
C000177581_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 10,300        
C000177581_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 11,348        
C000177581_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,083        
C000177581_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 12,073        
C000177581_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,682        
C000177581_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 10,555        
C000177581_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 11,325        
C000069436_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® Series Investment Grade Bond Fund</span>
C000069436_ClassMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000069436_ClassMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,687        
C000069436_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,841        
C000069436_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,793        
C000069436_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,890        
C000069436_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,860        
C000069436_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 13,125        
C000069436_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,667        
C000069436_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 11,665        
C000069436_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 12,632        
C000069436_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 13,104        
C000069436_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 U.S. Aggregate Bond Index</span>
C000069436_1_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000069436_1_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,597        
C000069436_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,649        
C000069436_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,537        
C000069436_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,609        
C000069436_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,360        
C000069436_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,350        
C000069436_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,928        
C000069436_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,797        
C000069436_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 11,585        
C000069436_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 11,949        
C000100043_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® U.S. Bond Index Fund</span>
C000100043_ClassMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000100043_ClassMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,598        
C000100043_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,639        
C000100043_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,509        
C000100043_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,594        
C000100043_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,346        
C000100043_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,324        
C000100043_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,904        
C000100043_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,777        
C000100043_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 11,554        
C000100043_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 11,913        
C000100043_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 U.S. Aggregate Bond Index</span>
C000100043_1_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000100043_1_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,597        
C000100043_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,649        
C000100043_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,537        
C000100043_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,609        
C000100043_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,360        
C000100043_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,350        
C000100043_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,928        
C000100043_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,797        
C000100043_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 11,585        
C000100043_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 11,949        
C000153158_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® Series Short-Term Credit Fund</span>
C000153158_ClassMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000153158_ClassMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,198        
C000153158_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,319        
C000153158_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,404        
C000153158_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 10,926        
C000153158_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 11,401        
C000153158_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 11,510        
C000153158_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,081        
C000153158_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 11,417        
C000153158_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 12,262        
C000153158_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 12,906        
C000153158_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 U.S. Credit 1-3 Years Bond Index</span>
C000153158_1_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000153158_1_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,238        
C000153158_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,401        
C000153158_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,463        
C000153158_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 10,995        
C000153158_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 11,436        
C000153158_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 11,544        
C000153158_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,098        
C000153158_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 11,344        
C000153158_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 12,143        
C000153158_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 12,777        
C000153158_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 U.S. Aggregate Bond Index</span>
C000153158_2_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000153158_2_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,597        
C000153158_2_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,649        
C000153158_2_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,537        
C000153158_2_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,609        
C000153158_2_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,360        
C000153158_2_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,350        
C000153158_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,928        
C000153158_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,797        
C000153158_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 11,585        
C000153158_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 11,949        
C000088100_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;">Class M</span>
C000088100_ClassMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 9,600        
C000088100_ClassMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,433        
C000088100_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,678        
C000088100_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,566        
C000088100_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,901        
C000088100_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,820        
C000088100_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 13,104        
C000088100_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,027        
C000088100_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 11,098        
C000088100_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 12,151        
C000088100_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 12,590        
C000088100_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 U.S. Credit Bond Index</span>
C000088100_1_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000088100_1_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,914        
C000088100_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,122        
C000088100_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 11,012        
C000088100_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 12,443        
C000088100_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 13,326        
C000088100_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 13,627        
C000088100_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,661        
C000088100_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 11,759        
C000088100_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 12,816        
C000088100_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 13,318        
C000088100_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 U.S. Aggregate Bond Index</span>
C000088100_2_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000088100_2_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,597        
C000088100_2_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,649        
C000088100_2_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,537        
C000088100_2_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,609        
C000088100_2_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,360        
C000088100_2_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,350        
C000088100_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,928        
C000088100_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,797        
C000088100_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 11,585        
C000088100_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 11,949        
C000088096_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® Corporate Bond Fund</span>
C000088096_ClassMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000088096_ClassMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,914        
C000088096_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,216        
C000088096_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 11,145        
C000088096_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 12,606        
C000088096_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 13,629        
C000088096_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 13,978        
C000088096_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,806        
C000088096_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 11,928        
C000088096_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 13,108        
C000088096_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 13,629        
C000088096_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 U.S. Credit Bond Index</span>
C000088096_1_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000088096_1_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,914        
C000088096_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,122        
C000088096_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 11,012        
C000088096_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 12,443        
C000088096_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 13,326        
C000088096_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 13,627        
C000088096_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,661        
C000088096_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 11,759        
C000088096_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 12,816        
C000088096_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 13,318        
C000088096_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 U.S. Aggregate Bond Index</span>
C000088096_2_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000088096_2_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,597        
C000088096_2_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,649        
C000088096_2_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,537        
C000088096_2_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,609        
C000088096_2_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,360        
C000088096_2_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,350        
C000088096_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,928        
C000088096_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,797        
C000088096_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 11,585        
C000088096_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 11,949        
C000088099_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;">Class C</span>
C000088099_ClassMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000088099_ClassMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,786        
C000088099_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,975        
C000088099_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,786        
C000088099_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 12,057        
C000088099_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,906        
C000088099_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 13,094        
C000088099_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,939        
C000088099_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,932        
C000088099_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 11,974        
C000088099_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 12,410        
C000088099_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 U.S. Credit Bond Index</span>
C000088099_1_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000088099_1_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,914        
C000088099_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,122        
C000088099_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 11,012        
C000088099_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 12,443        
C000088099_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 13,326        
C000088099_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 13,627        
C000088099_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,661        
C000088099_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 11,759        
C000088099_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 12,816        
C000088099_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 13,318        
C000088099_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 U.S. Aggregate Bond Index</span>
C000088099_2_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000088099_2_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,597        
C000088099_2_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,649        
C000088099_2_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,537        
C000088099_2_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,609        
C000088099_2_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,360        
C000088099_2_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,350        
C000088099_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,928        
C000088099_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,797        
C000088099_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 11,585        
C000088099_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 11,949        
C000205023_LG_ClassMember_8YRMember          
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>    
C000205023_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000205023_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,334        
C000205023_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,275        
C000205023_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,601        
C000205023_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,652        
C000205023_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,761        
C000205023_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 11,847        
C000205023_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 12,329        
C000205023_LG_1_AdditionalIndexMember_8YRMember          
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 U.S. Credit Bond Index</span>    
C000205023_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000205023_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,331        
C000205023_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,135        
C000205023_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,409        
C000205023_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,618        
C000205023_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,708        
C000205023_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 11,670        
C000205023_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 12,128        
C000205023_LG_2_AdditionalIndexMember_8YRMember          
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 U.S. Aggregate Bond Index</span>    
C000205023_2_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000205023_2_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,086        
C000205023_2_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 11,804        
C000205023_2_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 11,794        
C000205023_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,436        
C000205023_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,311        
C000205023_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 11,064        
C000205023_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 11,411        
C000088101_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;">Class I</span>
C000088101_ClassMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000088101_ClassMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,908        
C000088101_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,205        
C000088101_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 11,129        
C000088101_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 12,582        
C000088101_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 13,597        
C000088101_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 13,938        
C000088101_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,767        
C000088101_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 11,882        
C000088101_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 13,052        
C000088101_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 13,563        
C000088101_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 U.S. Credit Bond Index</span>
C000088101_1_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000088101_1_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,914        
C000088101_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,122        
C000088101_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 11,012        
C000088101_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 12,443        
C000088101_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 13,326        
C000088101_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 13,627        
C000088101_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,661        
C000088101_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 11,759        
C000088101_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 12,816        
C000088101_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 13,318        
C000088101_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 U.S. Aggregate Bond Index</span>
C000088101_2_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000088101_2_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,597        
C000088101_2_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,649        
C000088101_2_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,537        
C000088101_2_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,609        
C000088101_2_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,360        
C000088101_2_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,350        
C000088101_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,928        
C000088101_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,797        
C000088101_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 11,585        
C000088101_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 11,949        
C000088097_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;">Class A</span>
C000088097_ClassMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 9,600        
C000088097_ClassMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,442        
C000088097_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,695        
C000088097_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,592        
C000088097_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,939        
C000088097_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,868        
C000088097_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 13,157        
C000088097_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,076        
C000088097_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 11,154        
C000088097_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 12,218        
C000088097_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 12,663        
C000088097_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 U.S. Credit Bond Index</span>
C000088097_1_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000088097_1_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,914        
C000088097_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,122        
C000088097_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 11,012        
C000088097_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 12,443        
C000088097_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 13,326        
C000088097_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 13,627        
C000088097_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 11,661        
C000088097_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 11,759        
C000088097_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 12,816        
C000088097_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 13,318        
C000088097_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 U.S. Aggregate Bond Index</span>
C000088097_2_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000088097_2_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,597        
C000088097_2_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,649        
C000088097_2_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,537        
C000088097_2_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,609        
C000088097_2_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,360        
C000088097_2_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,350        
C000088097_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 10,928        
C000088097_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 10,797        
C000088097_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 11,585        
C000088097_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value $ 11,949