Investment Risks |
May 30, 2026 |
|---|---|
| FidelitySAIMunicipalMoneyMarketFund-PRO | Fidelity SAI Municipal Money Market Fund | Risk Lose Money [Member] | |
| Prospectus Line Items | |
| Risk [Text Block] | You could lose money by investing in the fund. |
| FidelitySAIMunicipalMoneyMarketFund-PRO | Fidelity SAI Municipal Money Market Fund | Risk Money Market Fund May Not Preserve Dollar [Member] | |
| Prospectus Line Items | |
| Risk [Text Block] | Because the share price of the fund will fluctuate, when you sell your shares, they may be worth more or less than what you originally paid for them. The fund may impose a fee upon the sale of your shares. |
| FidelitySAIMunicipalMoneyMarketFund-PRO | Fidelity SAI Municipal Money Market Fund | Risk Money Market Fund Sponsor May Not Provide Support [Member] | |
| Prospectus Line Items | |
| Risk [Text Block] | Fidelity Investments and its affiliates, the fund's sponsor, is not required to reimburse the fund for losses, and you should not expect that the sponsor will provide financial support to the fund at any time, including during periods of market stress. |
| FidelitySAIMunicipalMoneyMarketFund-PRO | Fidelity SAI Municipal Money Market Fund | Risk Not Insured Depository Institution [Member] | |
| Prospectus Line Items | |
| Risk [Text Block] | The fund generally must impose a fee when net sales of fund shares exceed certain levels. An investment in the fund is not a bank account and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. |
| FidelitySAIMunicipalMoneyMarketFund-PRO | Fidelity SAI Municipal Money Market Fund | InterestRateChangesMember | |
| Prospectus Line Items | |
| Risk [Text Block] | Interest Rate Changes. Interest rate increases can cause the price of a money market security to decrease. |
| FidelitySAIMunicipalMoneyMarketFund-PRO | Fidelity SAI Municipal Money Market Fund | IncomeRiskMember | |
| Prospectus Line Items | |
| Risk [Text Block] | Income Risk. A low or negative interest rate environment can adversely affect the fund's yield. |
| FidelitySAIMunicipalMoneyMarketFund-PRO | Fidelity SAI Municipal Money Market Fund | ForeignExposureMember | |
| Prospectus Line Items | |
| Risk [Text Block] | Foreign Exposure. Entities providing credit support or a maturity-shortening structure that are located in foreign countries can be affected by adverse political, regulatory, market, or economic developments in those countries . |
| FidelitySAIMunicipalMoneyMarketFund-PRO | Fidelity SAI Municipal Money Market Fund | IssuerSpecificChangesMember | |
| Prospectus Line Items | |
| Risk [Text Block] | Issuer-Specific Changes. A decline in the credit quality of an issuer or a provider of credit support (such as guarantees) or a maturity-shortening structure (such as demand and put features) for a security can cause the price of a money market security to decrease. |
| FidelitySAIMunicipalMoneyMarketFund-PRO | Fidelity SAI Municipal Money Market Fund | MunicipalMarketVolatilityMember | |
| Prospectus Line Items | |
| Risk [Text Block] | Municipal Market Volatility. The municipal market is volatile and can be significantly affected by adverse tax, legislative, or political changes and the financial condition of the issuers of municipal securities. |
| FidelitySAIMunicipalMoneyMarketFund-PRO | Fidelity SAI Municipal Money Market Fund | FloatingNavMember | |
| Prospectus Line Items | |
| Risk [Text Block] | Floating NAV. The fund does not maintain a constant NAV per share of $1.00. The value of the fund's shares will be calculated to four decimal places and will vary as a result of changes in the value of the securities in which the fund invests. |
| Document Type | 485BPOS |