v3.25.3
Shareholder Report, Line Graph (Details) - USD ($)
12 Months Ended 132 Months Ended
Aug. 31, 2025
Aug. 31, 2025
C000023057_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® Specialized High Income Central Fund</span>
C000023057_ClassMember_AsOf_2015Member    
Account Value [Line Items]    
Accumulated Value $ 10,000  
C000023057_ClassMember_AsOf_2016Member    
Account Value [Line Items]    
Accumulated Value 10,739  
C000023057_ClassMember_AsOf_2017Member    
Account Value [Line Items]    
Accumulated Value 11,532  
C000023057_ClassMember_AsOf_2018Member    
Account Value [Line Items]    
Accumulated Value 11,811  
C000023057_ClassMember_AsOf_2019Member    
Account Value [Line Items]    
Accumulated Value 12,842  
C000023057_ClassMember_AsOf_2020Member    
Account Value [Line Items]    
Accumulated Value 13,389  
C000023057_ClassMember_AsOf_2021Member    
Account Value [Line Items]    
Accumulated Value 14,254  
C000023057_ClassMember_AsOf_2022Member    
Account Value [Line Items]    
Accumulated Value 12,832  
C000023057_ClassMember_AsOf_2023Member    
Account Value [Line Items]    
Accumulated Value 13,546  
C000023057_ClassMember_AsOf_2024Member    
Account Value [Line Items]    
Accumulated Value 15,086  
C000023057_ClassMember_AsOf_2025Member    
Account Value [Line Items]    
Accumulated Value 16,244  
C000023057_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;">ICE® BofA® BB US High Yield Constrained Index</span>
C000023057_1_AdditionalIndexMember_AsOf_2015Member    
Account Value [Line Items]    
Accumulated Value 10,000  
C000023057_1_AdditionalIndexMember_AsOf_2016Member    
Account Value [Line Items]    
Accumulated Value 10,975  
C000023057_1_AdditionalIndexMember_AsOf_2017Member    
Account Value [Line Items]    
Accumulated Value 11,753  
C000023057_1_AdditionalIndexMember_AsOf_2018Member    
Account Value [Line Items]    
Accumulated Value 11,915  
C000023057_1_AdditionalIndexMember_AsOf_2019Member    
Account Value [Line Items]    
Accumulated Value 13,060  
C000023057_1_AdditionalIndexMember_AsOf_2020Member    
Account Value [Line Items]    
Accumulated Value 13,889  
C000023057_1_AdditionalIndexMember_AsOf_2021Member    
Account Value [Line Items]    
Accumulated Value 15,011  
C000023057_1_AdditionalIndexMember_AsOf_2022Member    
Account Value [Line Items]    
Accumulated Value 13,447  
C000023057_1_AdditionalIndexMember_AsOf_2023Member    
Account Value [Line Items]    
Accumulated Value 14,218  
C000023057_1_AdditionalIndexMember_AsOf_2024Member    
Account Value [Line Items]    
Accumulated Value 15,901  
C000023057_1_AdditionalIndexMember_AsOf_2025Member    
Account Value [Line Items]    
Accumulated Value 17,006  
C000023057_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. Universal Bond Index</span>
C000023057_2_AdditionalIndexMember_AsOf_2015Member    
Account Value [Line Items]    
Accumulated Value 10,000  
C000023057_2_AdditionalIndexMember_AsOf_2016Member    
Account Value [Line Items]    
Accumulated Value 10,650  
C000023057_2_AdditionalIndexMember_AsOf_2017Member    
Account Value [Line Items]    
Accumulated Value 10,793  
C000023057_2_AdditionalIndexMember_AsOf_2018Member    
Account Value [Line Items]    
Accumulated Value 10,693  
C000023057_2_AdditionalIndexMember_AsOf_2019Member    
Account Value [Line Items]    
Accumulated Value 11,770  
C000023057_2_AdditionalIndexMember_AsOf_2020Member    
Account Value [Line Items]    
Accumulated Value 12,525  
C000023057_2_AdditionalIndexMember_AsOf_2021Member    
Account Value [Line Items]    
Accumulated Value 12,636  
C000023057_2_AdditionalIndexMember_AsOf_2022Member    
Account Value [Line Items]    
Accumulated Value 11,138  
C000023057_2_AdditionalIndexMember_AsOf_2023Member    
Account Value [Line Items]    
Accumulated Value 11,094  
C000023057_2_AdditionalIndexMember_AsOf_2024Member    
Account Value [Line Items]    
Accumulated Value 11,973  
C000023057_2_AdditionalIndexMember_AsOf_2025Member    
Account Value [Line Items]    
Accumulated Value 12,419  
C000064553_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® High Income Central Fund</span>
C000064553_ClassMember_AsOf_2015Member    
Account Value [Line Items]    
Accumulated Value 10,000  
C000064553_ClassMember_AsOf_2016Member    
Account Value [Line Items]    
Accumulated Value 10,775  
C000064553_ClassMember_AsOf_2017Member    
Account Value [Line Items]    
Accumulated Value 11,810  
C000064553_ClassMember_AsOf_2018Member    
Account Value [Line Items]    
Accumulated Value 12,434  
C000064553_ClassMember_AsOf_2019Member    
Account Value [Line Items]    
Accumulated Value 13,253  
C000064553_ClassMember_AsOf_2020Member    
Account Value [Line Items]    
Accumulated Value 13,445  
C000064553_ClassMember_AsOf_2021Member    
Account Value [Line Items]    
Accumulated Value 15,457  
C000064553_ClassMember_AsOf_2022Member    
Account Value [Line Items]    
Accumulated Value 14,560  
C000064553_ClassMember_AsOf_2023Member    
Account Value [Line Items]    
Accumulated Value 15,561  
C000064553_ClassMember_AsOf_2024Member    
Account Value [Line Items]    
Accumulated Value 17,451  
C000064553_ClassMember_AsOf_2025Member    
Account Value [Line Items]    
Accumulated Value 19,351  
C000064553_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;">ICE® BofA® US High Yield Constrained Index</span>
C000064553_1_AdditionalIndexMember_AsOf_2015Member    
Account Value [Line Items]    
Accumulated Value 10,000  
C000064553_1_AdditionalIndexMember_AsOf_2016Member    
Account Value [Line Items]    
Accumulated Value 10,922  
C000064553_1_AdditionalIndexMember_AsOf_2017Member    
Account Value [Line Items]    
Accumulated Value 11,882  
C000064553_1_AdditionalIndexMember_AsOf_2018Member    
Account Value [Line Items]    
Accumulated Value 12,270  
C000064553_1_AdditionalIndexMember_AsOf_2019Member    
Account Value [Line Items]    
Accumulated Value 13,077  
C000064553_1_AdditionalIndexMember_AsOf_2020Member    
Account Value [Line Items]    
Accumulated Value 13,551  
C000064553_1_AdditionalIndexMember_AsOf_2021Member    
Account Value [Line Items]    
Accumulated Value 14,941  
C000064553_1_AdditionalIndexMember_AsOf_2022Member    
Account Value [Line Items]    
Accumulated Value 13,382  
C000064553_1_AdditionalIndexMember_AsOf_2023Member    
Account Value [Line Items]    
Accumulated Value 14,322  
C000064553_1_AdditionalIndexMember_AsOf_2024Member    
Account Value [Line Items]    
Accumulated Value 16,109  
C000064553_1_AdditionalIndexMember_AsOf_2025Member    
Account Value [Line Items]    
Accumulated Value 17,419  
C000064553_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. Universal Bond Index</span>
C000064553_2_AdditionalIndexMember_AsOf_2015Member    
Account Value [Line Items]    
Accumulated Value 10,000  
C000064553_2_AdditionalIndexMember_AsOf_2016Member    
Account Value [Line Items]    
Accumulated Value 10,650  
C000064553_2_AdditionalIndexMember_AsOf_2017Member    
Account Value [Line Items]    
Accumulated Value 10,793  
C000064553_2_AdditionalIndexMember_AsOf_2018Member    
Account Value [Line Items]    
Accumulated Value 10,693  
C000064553_2_AdditionalIndexMember_AsOf_2019Member    
Account Value [Line Items]    
Accumulated Value 11,770  
C000064553_2_AdditionalIndexMember_AsOf_2020Member    
Account Value [Line Items]    
Accumulated Value 12,525  
C000064553_2_AdditionalIndexMember_AsOf_2021Member    
Account Value [Line Items]    
Accumulated Value 12,636  
C000064553_2_AdditionalIndexMember_AsOf_2022Member    
Account Value [Line Items]    
Accumulated Value 11,138  
C000064553_2_AdditionalIndexMember_AsOf_2023Member    
Account Value [Line Items]    
Accumulated Value 11,094  
C000064553_2_AdditionalIndexMember_AsOf_2024Member    
Account Value [Line Items]    
Accumulated Value 11,973  
C000064553_2_AdditionalIndexMember_AsOf_2025Member    
Account Value [Line Items]    
Accumulated Value $ 12,419