v3.25.2
Shareholder Report, Line Graph (Details) - USD ($)
12 Months Ended 96 Months Ended 108 Months Ended 120 Months Ended 132 Months Ended
Apr. 30, 2025
Apr. 30, 2025
Apr. 30, 2025
Apr. 30, 2025
Apr. 30, 2025
C000170037_LG_ClassMember_10YRMember          
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® Large Cap Value Index Fund</span>  
C000170037_ClassMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value $ 10,000        
C000170037_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,348        
C000170037_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 12,205        
C000170037_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 13,321        
C000170037_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 11,850        
C000170037_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 17,294        
C000170037_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 17,514        
C000170037_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 17,720        
C000170037_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 20,110        
C000170037_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 21,824        
C000170037_LG_1_AdditionalIndexMember_10YRMember          
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;">Russell 1000® Value Index</span>  
C000170037_1_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000170037_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,355        
C000170037_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 12,207        
C000170037_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 13,314        
C000170037_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 11,848        
C000170037_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 17,289        
C000170037_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 17,516        
C000170037_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 17,729        
C000170037_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 20,108        
C000170037_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 21,828        
C000170037_LG_2_AdditionalIndexMember_10YRMember          
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;">Russell 1000® Index</span>  
C000170037_2_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000170037_2_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,501        
C000170037_2_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 13,015        
C000170037_2_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 14,750        
C000170037_2_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 14,763        
C000170037_2_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 22,068        
C000170037_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 21,605        
C000170037_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 21,997        
C000170037_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 27,017        
C000170037_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 30,244        
C000103368_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® Mid Cap Index Fund</span>
C000103368_ClassMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000103368_ClassMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 9,787        
C000103368_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,422        
C000103368_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 12,693        
C000103368_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 14,048        
C000103368_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,645        
C000103368_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 20,180        
C000103368_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 18,944        
C000103368_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 18,631        
C000103368_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 21,675        
C000103368_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 23,261        
C000103368_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;">Russell Midcap® Index</span>
C000103368_1_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000103368_1_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 9,786        
C000103368_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,420        
C000103368_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 12,696        
C000103368_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 14,053        
C000103368_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,648        
C000103368_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 20,182        
C000103368_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 18,951        
C000103368_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 18,631        
C000103368_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 21,677        
C000103368_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 23,267        
C000103368_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;">Russell 3000® Index</span>
C000103368_2_AdditionalIndexMember_AsOf_2015Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000103368_2_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 9,982        
C000103368_2_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,837        
C000103368_2_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 13,382        
C000103368_2_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 15,079        
C000103368_2_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 14,922        
C000103368_2_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 22,520        
C000103368_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 21,819        
C000103368_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 22,146        
C000103368_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 27,085        
C000103368_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 30,174        
C000177585_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® Mid Cap Index Fund</span>    
C000177585_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000177585_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,190        
C000177585_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,330        
C000177585_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,548        
C000177585_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 11,309        
C000177585_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 18,053        
C000177585_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 16,954        
C000177585_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 16,680        
C000177585_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 19,409        
C000177585_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;">Russell Midcap® Index</span>    
C000177585_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000177585_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,192        
C000177585_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,330        
C000177585_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,542        
C000177585_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 11,288        
C000177585_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 18,012        
C000177585_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 16,913        
C000177585_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 16,627        
C000177585_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 19,345        
C000177585_LG_2_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;">Russell 1000® Index</span>    
C000177585_2_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000177585_2_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,116        
C000177585_2_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,449        
C000177585_2_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,975        
C000177585_2_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 12,986        
C000177585_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 19,411        
C000177585_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 19,004        
C000177585_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 19,349        
C000177585_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 23,765        
C000170033_LG_ClassMember_10YRMember          
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® Large Cap Growth Index Fund</span>  
C000170033_ClassMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000170033_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,634        
C000170033_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 13,832        
C000170033_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 16,230        
C000170033_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 17,990        
C000170033_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 27,226        
C000170033_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 25,757        
C000170033_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 26,356        
C000170033_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 34,750        
C000170033_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 39,775        
C000170033_LG_1_AdditionalIndexMember_10YRMember          
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;">Russell 1000® Growth Index</span>  
C000170033_1_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000170033_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,645        
C000170033_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 13,853        
C000170033_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 16,268        
C000170033_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 18,030        
C000170033_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 27,300        
C000170033_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 25,840        
C000170033_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 26,444        
C000170033_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 34,853        
C000170033_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 39,917        
C000170033_LG_2_AdditionalIndexMember_10YRMember          
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;">Russell 1000® Index</span>  
C000170033_2_AdditionalIndexMember_AsOf_2016Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000170033_2_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 11,501        
C000170033_2_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 13,015        
C000170033_2_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 14,750        
C000170033_2_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 14,763        
C000170033_2_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 22,068        
C000170033_2_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 21,605        
C000170033_2_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 21,997        
C000170033_2_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 27,017        
C000170033_2_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 30,244        
C000177589_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® Small Cap Index Fund</span>    
C000177589_ClassMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000177589_ClassMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,310        
C000177589_ClassMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,519        
C000177589_ClassMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,052        
C000177589_ClassMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 10,096        
C000177589_ClassMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 17,670        
C000177589_ClassMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 14,688        
C000177589_ClassMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 14,180        
C000177589_ClassMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 16,090        
C000177589_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;">Russell 2000® Index</span>    
C000177589_1_AdditionalIndexMember_AsOf_2017Member          
Account Value [Line Items]          
Accumulated Value 10,000        
C000177589_1_AdditionalIndexMember_AsOf_2018Member          
Account Value [Line Items]          
Accumulated Value 10,316        
C000177589_1_AdditionalIndexMember_AsOf_2019Member          
Account Value [Line Items]          
Accumulated Value 11,506        
C000177589_1_AdditionalIndexMember_AsOf_2020Member          
Account Value [Line Items]          
Accumulated Value 12,037        
C000177589_1_AdditionalIndexMember_AsOf_2021Member          
Account Value [Line Items]          
Accumulated Value 10,064        
C000177589_1_AdditionalIndexMember_AsOf_2022Member          
Account Value [Line Items]          
Accumulated Value 17,603        
C000177589_1_AdditionalIndexMember_AsOf_2023Member          
Account Value [Line Items]          
Accumulated Value 14,634        
C000177589_1_AdditionalIndexMember_AsOf_2024Member          
Account Value [Line Items]          
Accumulated Value 14,100        
C000177589_1_AdditionalIndexMember_AsOf_2025Member          
Account Value [Line Items]          
Accumulated Value 15,978        
C000177589_LG_2_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;">Russell 3000® Index</span>    
C000177589_2_AdditionalIndexMember_AsOf_2017Member          
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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;">Russell 2000® Index</span>
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Account Value [Line Items]          
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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;">Russell 3000® Index</span>
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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 Large Cap Growth Index Fund</span>      
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Account Value [Line Items]          
Accumulated Value 10,000        
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Accumulated Value 22,692        
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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;">Russell 1000® Growth Index</span>      
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Account Value [Line Items]          
Accumulated Value 10,000        
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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;">Russell 1000® Index</span>      
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