Risk/Return Summary - FidelityOTCPortfolio-AMCIZPRO - FidelityOTCPortfolio-AMCIZPRO - Fidelity OTC Portfolio	Oct. 04, 2024
Risk Nondiversified Status [Text]
Prospectus Line Items
Risk Text Block	In addition, the fund is classified as non-diversified under the Investment Company Act of 1940 (1940 Act), which means that it has the ability to invest a greater portion of assets in securities of a smaller number of individual issuers than a diversified fund. As a result, changes in the market value of a single investment could cause greater fluctuations in share price than would occur in a more diversified fund.
Risk Lose Money [Text]
Prospectus Line Items
Risk Text Block	You could lose money by investing in the fund.
Risk Not Insured Depository Institution [Text]
Prospectus Line Items
Risk Text Block	An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency .