v3.25.3
Shareholder Report, Line Graph (Details) - USD ($)
12 Months Ended 24 Months Ended 36 Months Ended 48 Months Ended 60 Months Ended 96 Months Ended 132 Months Ended
Aug. 31, 2025
Aug. 31, 2025
Aug. 31, 2025
Aug. 31, 2025
Aug. 31, 2025
Aug. 31, 2025
Aug. 31, 2025
C000201028_0_LG_BBIndexMember_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>  
C000201028_0_BBIndexMember_AsOf_2018Member              
Account Value [Line Items]              
Accumulated Value $ 10,000            
C000201028_0_BBIndexMember_AsOf_2019Member              
Account Value [Line Items]              
Accumulated Value 10,120            
C000201028_0_BBIndexMember_AsOf_2020Member              
Account Value [Line Items]              
Accumulated Value 11,150            
C000201028_0_BBIndexMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 11,871            
C000201028_0_BBIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 11,861            
C000201028_0_BBIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 10,496            
C000201028_0_BBIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 10,370            
C000201028_0_BBIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 11,127            
C000131661_0_LG_BBIndexMember_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>
C000131661_0_BBIndexMember_AsOf_2015Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000131661_0_BBIndexMember_AsOf_2016Member              
Account Value [Line Items]              
Accumulated Value 10,597            
C000131661_0_BBIndexMember_AsOf_2017Member              
Account Value [Line Items]              
Accumulated Value 10,649            
C000131661_0_BBIndexMember_AsOf_2018Member              
Account Value [Line Items]              
Accumulated Value 10,537            
C000131661_0_BBIndexMember_AsOf_2019Member              
Account Value [Line Items]              
Accumulated Value 11,609            
C000131661_0_BBIndexMember_AsOf_2020Member              
Account Value [Line Items]              
Accumulated Value 12,360            
C000131661_0_BBIndexMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 12,350            
C000131661_0_BBIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,928            
C000131661_0_BBIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 10,797            
C000131661_0_BBIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 11,585            
C000131661_0_BBIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 11,949            
C000131659_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® Total Bond ETF</span>
C000131659_ClassMember_AsOf_2015Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000131659_ClassMember_AsOf_2016Member              
Account Value [Line Items]              
Accumulated Value 10,685            
C000131659_ClassMember_AsOf_2017Member              
Account Value [Line Items]              
Accumulated Value 10,897            
C000131659_ClassMember_AsOf_2018Member              
Account Value [Line Items]              
Accumulated Value 10,821            
C000131659_ClassMember_AsOf_2019Member              
Account Value [Line Items]              
Accumulated Value 11,874            
C000131659_ClassMember_AsOf_2020Member              
Account Value [Line Items]              
Accumulated Value 12,836            
C000131659_ClassMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 13,079            
C000131659_ClassMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 11,599            
C000131659_ClassMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 11,622            
C000131659_ClassMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 12,580            
C000131659_ClassMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 13,068            
C000131659_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>
C000131659_1_AdditionalIndexMember_AsOf_2015Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000131659_1_AdditionalIndexMember_AsOf_2016Member              
Account Value [Line Items]              
Accumulated Value 10,597            
C000131659_1_AdditionalIndexMember_AsOf_2017Member              
Account Value [Line Items]              
Accumulated Value 10,649            
C000131659_1_AdditionalIndexMember_AsOf_2018Member              
Account Value [Line Items]              
Accumulated Value 10,537            
C000131659_1_AdditionalIndexMember_AsOf_2019Member              
Account Value [Line Items]              
Accumulated Value 11,609            
C000131659_1_AdditionalIndexMember_AsOf_2020Member              
Account Value [Line Items]              
Accumulated Value 12,360            
C000131659_1_AdditionalIndexMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 12,350            
C000131659_1_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,928            
C000131659_1_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 10,797            
C000131659_1_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 11,585            
C000131659_1_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 11,949            
C000239880_LG_ClassMember_3YRMember              
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® Tactical Bond ETF</span>        
C000239880_ClassMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000239880_ClassMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 9,918            
C000239880_ClassMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 10,757            
C000239880_LG_1_AdditionalIndexMember_3YRMember              
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>        
C000239880_1_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000239880_1_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 9,831            
C000239880_1_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 10,548            
C000235242_LG_ClassMember_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;">Fidelity® Sustainable Low Duration Bond ETF</span>      
C000235242_ClassMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000235242_ClassMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 10,016            
C000235242_ClassMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 10,444            
C000235242_ClassMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 11,053            
C000235242_LG_1_AdditionalIndexMember_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 US Treasury Bill: 6-9 Months Index</span>      
C000235242_1_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000235242_1_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 9,991            
C000235242_1_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 10,302            
C000235242_1_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 10,856            
C000235242_LG_2_AdditionalIndexMember_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 U.S. Aggregate Bond Index</span>      
C000235242_2_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000235242_2_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 9,847            
C000235242_2_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 9,730            
C000235242_2_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 10,440            
C000235241_LG_ClassMember_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;">Fidelity® Sustainable Core Plus Bond ETF</span>      
C000235241_ClassMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000235241_ClassMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 9,728            
C000235241_ClassMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 9,719            
C000235241_ClassMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 10,527            
C000235241_LG_1_AdditionalIndexMember_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 MSCI U.S. Aggregate ESG Choice Bond Index</span>      
C000235241_1_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000235241_1_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 9,851            
C000235241_1_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 9,737            
C000235241_1_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 10,444            
C000235241_LG_2_AdditionalIndexMember_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 U.S. Aggregate Bond Index</span>      
C000235241_2_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000235241_2_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 9,847            
C000235241_2_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 9,730            
C000235241_2_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 10,440            
C000201028_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;">Fidelity® Low Duration Bond Factor ETF</span>  
C000201028_ClassMember_AsOf_2018Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000201028_ClassMember_AsOf_2019Member              
Account Value [Line Items]              
Accumulated Value 10,075            
C000201028_ClassMember_AsOf_2020Member              
Account Value [Line Items]              
Accumulated Value 10,473            
C000201028_ClassMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 10,733            
C000201028_ClassMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,772            
C000201028_ClassMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 10,607            
C000201028_ClassMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 11,123            
C000201028_ClassMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 11,861            
C000201028_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;">Fidelity Low Duration Investment Grade Factor Index℠</span>  
C000201028_1_AdditionalIndexMember_AsOf_2018Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000201028_1_AdditionalIndexMember_AsOf_2019Member              
Account Value [Line Items]              
Accumulated Value 10,076            
C000201028_1_AdditionalIndexMember_AsOf_2020Member              
Account Value [Line Items]              
Accumulated Value 10,497            
C000201028_1_AdditionalIndexMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 10,795            
C000201028_1_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,854            
C000201028_1_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 10,713            
C000201028_1_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 11,252            
C000201028_1_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 12,018            
C000201028_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 US Treasury Bill: 6-9 Months Index</span>  
C000201028_2_AdditionalIndexMember_AsOf_2018Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000201028_2_AdditionalIndexMember_AsOf_2019Member              
Account Value [Line Items]              
Accumulated Value 10,045            
C000201028_2_AdditionalIndexMember_AsOf_2020Member              
Account Value [Line Items]              
Accumulated Value 10,314            
C000201028_2_AdditionalIndexMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 10,503            
C000201028_2_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,514            
C000201028_2_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 10,474            
C000201028_2_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 10,800            
C000201028_2_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 11,380            
C000131661_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® Limited Term Bond ETF</span>
C000131661_ClassMember_AsOf_2015Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000131661_ClassMember_AsOf_2016Member              
Account Value [Line Items]              
Accumulated Value 10,337            
C000131661_ClassMember_AsOf_2017Member              
Account Value [Line Items]              
Accumulated Value 10,468            
C000131661_ClassMember_AsOf_2018Member              
Account Value [Line Items]              
Accumulated Value 10,443            
C000131661_ClassMember_AsOf_2019Member              
Account Value [Line Items]              
Accumulated Value 11,093            
C000131661_ClassMember_AsOf_2020Member              
Account Value [Line Items]              
Accumulated Value 11,652            
C000131661_ClassMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 11,749            
C000131661_ClassMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,999            
C000131661_ClassMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 11,221            
C000131661_ClassMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 12,105            
C000131661_ClassMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 12,790            
C000131661_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. 1-5 Year Government/Credit Bond Index</span>
C000131661_1_AdditionalIndexMember_AsOf_2015Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000131661_1_AdditionalIndexMember_AsOf_2016Member              
Account Value [Line Items]              
Accumulated Value 10,238            
C000131661_1_AdditionalIndexMember_AsOf_2017Member              
Account Value [Line Items]              
Accumulated Value 10,334            
C000131661_1_AdditionalIndexMember_AsOf_2018Member              
Account Value [Line Items]              
Accumulated Value 10,289            
C000131661_1_AdditionalIndexMember_AsOf_2019Member              
Account Value [Line Items]              
Accumulated Value 10,902            
C000131661_1_AdditionalIndexMember_AsOf_2020Member              
Account Value [Line Items]              
Accumulated Value 11,417            
C000131661_1_AdditionalIndexMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 11,454            
C000131661_1_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,785            
C000131661_1_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 10,913            
C000131661_1_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 11,641            
C000131661_1_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 12,198            
C000131661_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;">Fidelity Limited Term Composite Index℠</span>
C000131661_2_AdditionalIndexMember_AsOf_2015Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000131661_2_AdditionalIndexMember_AsOf_2016Member              
Account Value [Line Items]              
Accumulated Value 10,307            
C000131661_2_AdditionalIndexMember_AsOf_2017Member              
Account Value [Line Items]              
Accumulated Value 10,465            
C000131661_2_AdditionalIndexMember_AsOf_2018Member              
Account Value [Line Items]              
Accumulated Value 10,451            
C000131661_2_AdditionalIndexMember_AsOf_2019Member              
Account Value [Line Items]              
Accumulated Value 11,120            
C000131661_2_AdditionalIndexMember_AsOf_2020Member              
Account Value [Line Items]              
Accumulated Value 11,679            
C000131661_2_AdditionalIndexMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 11,788            
C000131661_2_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 11,078            
C000131661_2_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 11,279            
C000131661_2_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 12,127            
C000131661_2_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 12,792            
C000225827_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® Investment Grade Securitized ETF</span>    
C000225827_ClassMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000225827_ClassMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,036            
C000225827_ClassMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 8,983            
C000225827_ClassMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 8,795            
C000225827_ClassMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 9,525            
C000225827_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 U.S. Securitized Index</span>    
C000225827_1_AdditionalIndexMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000225827_1_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,018            
C000225827_1_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 9,044            
C000225827_1_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 8,867            
C000225827_1_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 9,537            
C000225827_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 U.S. Aggregate Bond Index</span>    
C000225827_2_AdditionalIndexMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000225827_2_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,156            
C000225827_2_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 8,986            
C000225827_2_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 8,879            
C000225827_2_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 9,527            
C000225826_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® Investment Grade Bond ETF</span>    
C000225826_ClassMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000225826_ClassMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,216            
C000225826_ClassMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 9,026            
C000225826_ClassMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 8,951            
C000225826_ClassMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 9,646            
C000225826_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 U.S. Aggregate Bond Index</span>    
C000225826_1_AdditionalIndexMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000225826_1_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,156            
C000225826_1_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 8,986            
C000225826_1_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 8,879            
C000225826_1_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 9,527            
C000125598_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 ETF</span>
C000125598_ClassMember_AsOf_2015Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000125598_ClassMember_AsOf_2016Member              
Account Value [Line Items]              
Accumulated Value 10,930            
C000125598_ClassMember_AsOf_2017Member              
Account Value [Line Items]              
Accumulated Value 11,196            
C000125598_ClassMember_AsOf_2018Member              
Account Value [Line Items]              
Accumulated Value 11,038            
C000125598_ClassMember_AsOf_2019Member              
Account Value [Line Items]              
Accumulated Value 12,516            
C000125598_ClassMember_AsOf_2020Member              
Account Value [Line Items]              
Accumulated Value 13,524            
C000125598_ClassMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 13,945            
C000125598_ClassMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 11,811            
C000125598_ClassMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 11,952            
C000125598_ClassMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 13,148            
C000125598_ClassMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 13,713            
C000125598_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>
C000125598_1_AdditionalIndexMember_AsOf_2015Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000125598_1_AdditionalIndexMember_AsOf_2016Member              
Account Value [Line Items]              
Accumulated Value 10,914            
C000125598_1_AdditionalIndexMember_AsOf_2017Member              
Account Value [Line Items]              
Accumulated Value 11,122            
C000125598_1_AdditionalIndexMember_AsOf_2018Member              
Account Value [Line Items]              
Accumulated Value 11,012            
C000125598_1_AdditionalIndexMember_AsOf_2019Member              
Account Value [Line Items]              
Accumulated Value 12,443            
C000125598_1_AdditionalIndexMember_AsOf_2020Member              
Account Value [Line Items]              
Accumulated Value 13,326            
C000125598_1_AdditionalIndexMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 13,627            
C000125598_1_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 11,661            
C000125598_1_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 11,759            
C000125598_1_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 12,816            
C000125598_1_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 13,318            
C000125598_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>
C000125598_2_AdditionalIndexMember_AsOf_2015Member              
Account Value [Line Items]              
Accumulated Value 10,000            
C000125598_2_AdditionalIndexMember_AsOf_2016Member              
Account Value [Line Items]              
Accumulated Value 10,597            
C000125598_2_AdditionalIndexMember_AsOf_2017Member              
Account Value [Line Items]              
Accumulated Value 10,649            
C000125598_2_AdditionalIndexMember_AsOf_2018Member              
Account Value [Line Items]              
Accumulated Value 10,537            
C000125598_2_AdditionalIndexMember_AsOf_2019Member              
Account Value [Line Items]              
Accumulated Value 11,609            
C000125598_2_AdditionalIndexMember_AsOf_2020Member              
Account Value [Line Items]              
Accumulated Value 12,360            
C000125598_2_AdditionalIndexMember_AsOf_2021Member              
Account Value [Line Items]              
Accumulated Value 12,350            
C000125598_2_AdditionalIndexMember_AsOf_2022Member              
Account Value [Line Items]              
Accumulated Value 10,928            
C000125598_2_AdditionalIndexMember_AsOf_2023Member              
Account Value [Line Items]              
Accumulated Value 10,797            
C000125598_2_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 11,585            
C000125598_2_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 11,949            
C000248144_LG_ClassMember_2YRMember              
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® Low Duration Bond ETF</span>          
C000248144_ClassMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 10,006            
C000248144_ClassMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 10,301            
C000248144_LG_1_AdditionalIndexMember_2YRMember              
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 US Treasury Bill: 6-9 Months Index</span>          
C000248144_1_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 10,008            
C000248144_1_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value 10,283            
C000248144_LG_2_AdditionalIndexMember_2YRMember              
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>          
C000248144_2_AdditionalIndexMember_AsOf_2024Member              
Account Value [Line Items]              
Accumulated Value 10,047            
C000248144_2_AdditionalIndexMember_AsOf_2025Member              
Account Value [Line Items]              
Accumulated Value $ 10,533