v3.23.1
Risk/Return Detail Data - FidelityLimitedTermGovernmentFund-PRO
Jan. 28, 2023
USD ($)
Risk/Return:  
Registrant Name Fidelity Advisor Series IV
FidelityLimitedTermGovernmentFund-PRO | Fidelity Limited Term Government Fund  
Risk/Return:  
Supplement to Prospectus [Text Block] Supplement to the Fidelity® Limited Term Government Fund January 28, 2023 Prospectus
Operating Expenses Caption [Text] Annual Operating Expenses
Expenses Restated to Reflect Current [Text] A Adjusted to reflect current fees.
FidelityLimitedTermGovernmentFund-PRO | Fidelity Limited Term Government Fund | Fidelity Limited Term Government Fund  
Risk/Return:  
Management fee 0.20% [1]
Distribution and/or Service (12b-1) fees none
Other expenses 0.10% [1]
Total annual operating expenses 0.30%
1 year $ 31
3 years 97
5 years 169
10 years $ 381
[1] A Adjusted to reflect current fees.