v3.26.3
Shareholder Report, Line Graph (Details) - USD ($)
12 Months Ended 36 Months Ended 48 Months Ended 72 Months Ended 108 Months Ended 132 Months Ended
Aug. 31, 2026
Aug. 31, 2026
Aug. 31, 2026
Aug. 31, 2026
Aug. 31, 2026
Aug. 31, 2026
C000201028_0_LG_BBIndexMember_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>  
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          
C000201028_0_BBIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 11,476          
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_2016Member            
Account Value [Line Items]            
Accumulated Value 10,000          
C000131661_0_BBIndexMember_AsOf_2017Member            
Account Value [Line Items]            
Accumulated Value 10,049          
C000131661_0_BBIndexMember_AsOf_2018Member            
Account Value [Line Items]            
Accumulated Value 9,944          
C000131661_0_BBIndexMember_AsOf_2019Member            
Account Value [Line Items]            
Accumulated Value 10,955          
C000131661_0_BBIndexMember_AsOf_2020Member            
Account Value [Line Items]            
Accumulated Value 11,665          
C000131661_0_BBIndexMember_AsOf_2021Member            
Account Value [Line Items]            
Accumulated Value 11,655          
C000131661_0_BBIndexMember_AsOf_2022Member            
Account Value [Line Items]            
Accumulated Value 10,313          
C000131661_0_BBIndexMember_AsOf_2023Member            
Account Value [Line Items]            
Accumulated Value 10,189          
C000131661_0_BBIndexMember_AsOf_2024Member            
Account Value [Line Items]            
Accumulated Value 10,933          
C000131661_0_BBIndexMember_AsOf_2025Member            
Account Value [Line Items]            
Accumulated Value 11,276          
C000131661_0_BBIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 11,489          
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_2016Member            
Account Value [Line Items]            
Accumulated Value 10,000          
C000131659_ClassMember_AsOf_2017Member            
Account Value [Line Items]            
Accumulated Value 10,198          
C000131659_ClassMember_AsOf_2018Member            
Account Value [Line Items]            
Accumulated Value 10,128          
C000131659_ClassMember_AsOf_2019Member            
Account Value [Line Items]            
Accumulated Value 11,113          
C000131659_ClassMember_AsOf_2020Member            
Account Value [Line Items]            
Accumulated Value 12,013          
C000131659_ClassMember_AsOf_2021Member            
Account Value [Line Items]            
Accumulated Value 12,241          
C000131659_ClassMember_AsOf_2022Member            
Account Value [Line Items]            
Accumulated Value 10,855          
C000131659_ClassMember_AsOf_2023Member            
Account Value [Line Items]            
Accumulated Value 10,877          
C000131659_ClassMember_AsOf_2024Member            
Account Value [Line Items]            
Accumulated Value 11,774          
C000131659_ClassMember_AsOf_2025Member            
Account Value [Line Items]            
Accumulated Value 12,230          
C000131659_ClassMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 12,494          
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_2016Member            
Account Value [Line Items]            
Accumulated Value 10,000          
C000131659_1_AdditionalIndexMember_AsOf_2017Member            
Account Value [Line Items]            
Accumulated Value 10,049          
C000131659_1_AdditionalIndexMember_AsOf_2018Member            
Account Value [Line Items]            
Accumulated Value 9,944          
C000131659_1_AdditionalIndexMember_AsOf_2019Member            
Account Value [Line Items]            
Accumulated Value 10,955          
C000131659_1_AdditionalIndexMember_AsOf_2020Member            
Account Value [Line Items]            
Accumulated Value 11,665          
C000131659_1_AdditionalIndexMember_AsOf_2021Member            
Account Value [Line Items]            
Accumulated Value 11,655          
C000131659_1_AdditionalIndexMember_AsOf_2022Member            
Account Value [Line Items]            
Accumulated Value 10,313          
C000131659_1_AdditionalIndexMember_AsOf_2023Member            
Account Value [Line Items]            
Accumulated Value 10,189          
C000131659_1_AdditionalIndexMember_AsOf_2024Member            
Account Value [Line Items]            
Accumulated Value 10,933          
C000131659_1_AdditionalIndexMember_AsOf_2025Member            
Account Value [Line Items]            
Accumulated Value 11,276          
C000131659_1_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 11,489          
C000239880_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® 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_ClassMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 11,215          
C000239880_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 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          
C000239880_1_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 10,879          
C000201028_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® 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_ClassMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 12,480          
C000201028_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 US Treasury Bill: 6-9 Months 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 10,045          
C000201028_1_AdditionalIndexMember_AsOf_2020Member            
Account Value [Line Items]            
Accumulated Value 10,314          
C000201028_1_AdditionalIndexMember_AsOf_2021Member            
Account Value [Line Items]            
Accumulated Value 10,503          
C000201028_1_AdditionalIndexMember_AsOf_2022Member            
Account Value [Line Items]            
Accumulated Value 10,514          
C000201028_1_AdditionalIndexMember_AsOf_2023Member            
Account Value [Line Items]            
Accumulated Value 10,474          
C000201028_1_AdditionalIndexMember_AsOf_2024Member            
Account Value [Line Items]            
Accumulated Value 10,800          
C000201028_1_AdditionalIndexMember_AsOf_2025Member            
Account Value [Line Items]            
Accumulated Value 11,380          
C000201028_1_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 11,868          
C000201028_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;">Fid Low Duration Investment Grade Factor 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 10,076          
C000201028_2_AdditionalIndexMember_AsOf_2020Member            
Account Value [Line Items]            
Accumulated Value 10,497          
C000201028_2_AdditionalIndexMember_AsOf_2021Member            
Account Value [Line Items]            
Accumulated Value 10,795          
C000201028_2_AdditionalIndexMember_AsOf_2022Member            
Account Value [Line Items]            
Accumulated Value 10,854          
C000201028_2_AdditionalIndexMember_AsOf_2023Member            
Account Value [Line Items]            
Accumulated Value 10,713          
C000201028_2_AdditionalIndexMember_AsOf_2024Member            
Account Value [Line Items]            
Accumulated Value 11,252          
C000201028_2_AdditionalIndexMember_AsOf_2025Member            
Account Value [Line Items]            
Accumulated Value 12,018          
C000201028_2_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 12,653          
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_2016Member            
Account Value [Line Items]            
Accumulated Value 10,000          
C000131661_ClassMember_AsOf_2017Member            
Account Value [Line Items]            
Accumulated Value 10,126          
C000131661_ClassMember_AsOf_2018Member            
Account Value [Line Items]            
Accumulated Value 10,103          
C000131661_ClassMember_AsOf_2019Member            
Account Value [Line Items]            
Accumulated Value 10,731          
C000131661_ClassMember_AsOf_2020Member            
Account Value [Line Items]            
Accumulated Value 11,272          
C000131661_ClassMember_AsOf_2021Member            
Account Value [Line Items]            
Accumulated Value 11,366          
C000131661_ClassMember_AsOf_2022Member            
Account Value [Line Items]            
Accumulated Value 10,641          
C000131661_ClassMember_AsOf_2023Member            
Account Value [Line Items]            
Accumulated Value 10,855          
C000131661_ClassMember_AsOf_2024Member            
Account Value [Line Items]            
Accumulated Value 11,711          
C000131661_ClassMember_AsOf_2025Member            
Account Value [Line Items]            
Accumulated Value 12,373          
C000131661_ClassMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 12,725          
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_2016Member            
Account Value [Line Items]            
Accumulated Value 10,000          
C000131661_1_AdditionalIndexMember_AsOf_2017Member            
Account Value [Line Items]            
Accumulated Value 10,093          
C000131661_1_AdditionalIndexMember_AsOf_2018Member            
Account Value [Line Items]            
Accumulated Value 10,049          
C000131661_1_AdditionalIndexMember_AsOf_2019Member            
Account Value [Line Items]            
Accumulated Value 10,648          
C000131661_1_AdditionalIndexMember_AsOf_2020Member            
Account Value [Line Items]            
Accumulated Value 11,151          
C000131661_1_AdditionalIndexMember_AsOf_2021Member            
Account Value [Line Items]            
Accumulated Value 11,188          
C000131661_1_AdditionalIndexMember_AsOf_2022Member            
Account Value [Line Items]            
Accumulated Value 10,534          
C000131661_1_AdditionalIndexMember_AsOf_2023Member            
Account Value [Line Items]            
Accumulated Value 10,659          
C000131661_1_AdditionalIndexMember_AsOf_2024Member            
Account Value [Line Items]            
Accumulated Value 11,370          
C000131661_1_AdditionalIndexMember_AsOf_2025Member            
Account Value [Line Items]            
Accumulated Value 11,914          
C000131661_1_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 12,170          
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_2016Member            
Account Value [Line Items]            
Accumulated Value 10,000          
C000131661_2_AdditionalIndexMember_AsOf_2017Member            
Account Value [Line Items]            
Accumulated Value 10,153          
C000131661_2_AdditionalIndexMember_AsOf_2018Member            
Account Value [Line Items]            
Accumulated Value 10,139          
C000131661_2_AdditionalIndexMember_AsOf_2019Member            
Account Value [Line Items]            
Accumulated Value 10,788          
C000131661_2_AdditionalIndexMember_AsOf_2020Member            
Account Value [Line Items]            
Accumulated Value 11,331          
C000131661_2_AdditionalIndexMember_AsOf_2021Member            
Account Value [Line Items]            
Accumulated Value 11,437          
C000131661_2_AdditionalIndexMember_AsOf_2022Member            
Account Value [Line Items]            
Accumulated Value 10,748          
C000131661_2_AdditionalIndexMember_AsOf_2023Member            
Account Value [Line Items]            
Accumulated Value 10,943          
C000131661_2_AdditionalIndexMember_AsOf_2024Member            
Account Value [Line Items]            
Accumulated Value 11,766          
C000131661_2_AdditionalIndexMember_AsOf_2025Member            
Account Value [Line Items]            
Accumulated Value 12,411          
C000131661_2_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 12,758          
C000225827_LG_ClassMember_6YRMember            
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_ClassMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 9,874          
C000225827_LG_1_AdditionalIndexMember_6YRMember            
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_1_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 9,872          
C000225827_LG_2_AdditionalIndexMember_6YRMember            
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          
C000225827_2_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 9,826          
C000225826_LG_ClassMember_6YRMember            
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_ClassMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 9,954          
C000225826_LG_1_AdditionalIndexMember_6YRMember            
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          
C000225826_1_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 9,826          
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_2016Member            
Account Value [Line Items]            
Accumulated Value 10,000          
C000125598_ClassMember_AsOf_2017Member            
Account Value [Line Items]            
Accumulated Value 10,243          
C000125598_ClassMember_AsOf_2018Member            
Account Value [Line Items]            
Accumulated Value 10,099          
C000125598_ClassMember_AsOf_2019Member            
Account Value [Line Items]            
Accumulated Value 11,451          
C000125598_ClassMember_AsOf_2020Member            
Account Value [Line Items]            
Accumulated Value 12,374          
C000125598_ClassMember_AsOf_2021Member            
Account Value [Line Items]            
Accumulated Value 12,759          
C000125598_ClassMember_AsOf_2022Member            
Account Value [Line Items]            
Accumulated Value 10,806          
C000125598_ClassMember_AsOf_2023Member            
Account Value [Line Items]            
Accumulated Value 10,935          
C000125598_ClassMember_AsOf_2024Member            
Account Value [Line Items]            
Accumulated Value 12,029          
C000125598_ClassMember_AsOf_2025Member            
Account Value [Line Items]            
Accumulated Value 12,546          
C000125598_ClassMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 12,764          
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_2016Member            
Account Value [Line Items]            
Accumulated Value 10,000          
C000125598_1_AdditionalIndexMember_AsOf_2017Member            
Account Value [Line Items]            
Accumulated Value 10,190          
C000125598_1_AdditionalIndexMember_AsOf_2018Member            
Account Value [Line Items]            
Accumulated Value 10,090          
C000125598_1_AdditionalIndexMember_AsOf_2019Member            
Account Value [Line Items]            
Accumulated Value 11,400          
C000125598_1_AdditionalIndexMember_AsOf_2020Member            
Account Value [Line Items]            
Accumulated Value 12,209          
C000125598_1_AdditionalIndexMember_AsOf_2021Member            
Account Value [Line Items]            
Accumulated Value 12,486          
C000125598_1_AdditionalIndexMember_AsOf_2022Member            
Account Value [Line Items]            
Accumulated Value 10,684          
C000125598_1_AdditionalIndexMember_AsOf_2023Member            
Account Value [Line Items]            
Accumulated Value 10,774          
C000125598_1_AdditionalIndexMember_AsOf_2024Member            
Account Value [Line Items]            
Accumulated Value 11,742          
C000125598_1_AdditionalIndexMember_AsOf_2025Member            
Account Value [Line Items]            
Accumulated Value 12,203          
C000125598_1_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 12,444          
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_2016Member            
Account Value [Line Items]            
Accumulated Value 10,000          
C000125598_2_AdditionalIndexMember_AsOf_2017Member            
Account Value [Line Items]            
Accumulated Value 10,049          
C000125598_2_AdditionalIndexMember_AsOf_2018Member            
Account Value [Line Items]            
Accumulated Value 9,944          
C000125598_2_AdditionalIndexMember_AsOf_2019Member            
Account Value [Line Items]            
Accumulated Value 10,955          
C000125598_2_AdditionalIndexMember_AsOf_2020Member            
Account Value [Line Items]            
Accumulated Value 11,665          
C000125598_2_AdditionalIndexMember_AsOf_2021Member            
Account Value [Line Items]            
Accumulated Value 11,655          
C000125598_2_AdditionalIndexMember_AsOf_2022Member            
Account Value [Line Items]            
Accumulated Value 10,313          
C000125598_2_AdditionalIndexMember_AsOf_2023Member            
Account Value [Line Items]            
Accumulated Value 10,189          
C000125598_2_AdditionalIndexMember_AsOf_2024Member            
Account Value [Line Items]            
Accumulated Value 10,933          
C000125598_2_AdditionalIndexMember_AsOf_2025Member            
Account Value [Line Items]            
Accumulated Value 11,276          
C000125598_2_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 11,489          
C000248144_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® 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_ClassMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 10,818          
C000248144_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 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_1_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value 10,724          
C000248144_LG_2_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>        
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          
C000248144_2_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value $ 10,863          
C000269153_LG_ClassMember_1YRMember            
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® AAA CLO ETF</span>          
C000269153_ClassMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value $ 10,000          
C000269153_LG_1_AdditionalIndexMember_1YRMember            
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;">J.P. Morgan CLOIE AAA Index</span>          
C000269153_1_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value $ 10,000          
C000269153_LG_2_AdditionalIndexMember_1YRMember            
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>          
C000269153_2_AdditionalIndexMember_AsOf_2026Member            
Account Value [Line Items]            
Accumulated Value $ 10,000