Investment Risks |
Sep. 30, 2025 |
|---|---|
| SelectUtilitiesPortfolio-AMCIZPro | Select Utilities Portfolio | Risk Nondiversified Status [Member] | |
| 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. |
| SelectUtilitiesPortfolio-AMCIZPro | Select Utilities Portfolio | Risk Lose Money [Member] | |
| Prospectus Line Items | |
| Risk [Text Block] | You could lose money by investing in the fund. |
| SelectUtilitiesPortfolio-AMCIZPro | Select Utilities Portfolio | Risk Not Insured Depository Institution [Member] | |
| 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 . |
| SelectUtilitiesPortfolio-AMCIZPro | Select Utilities Portfolio | ForeignExposureMember | |
| Prospectus Line Items | |
| Risk [Text Block] | Foreign Exposure. Foreign markets can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market. |
| SelectUtilitiesPortfolio-AMCIZPro | Select Utilities Portfolio | IssuerSpecificChangesMember | |
| Prospectus Line Items | |
| Risk [Text Block] | Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. The value of securities of smaller issuers can be more volatile than that of larger issuers. |
| SelectUtilitiesPortfolio-AMCIZPro | Select Utilities Portfolio | StockMarketVolatilityMember | |
| Prospectus Line Items | |
| Risk [Text Block] | Stock Market Volatility. Stock markets are volatile and can decline significantly in response to adverse issuer, political, regulatory, market, or economic developments. Different parts of the market, including different market sectors, and different types of securities can react differently to these developments. |
| SelectUtilitiesPortfolio-AMCIZPro | Select Utilities Portfolio | UtilitiesIndustryConcentrationMember | |
| Prospectus Line Items | |
| Risk [Text Block] | Utilities Industry Concentration. The utilities industries can be significantly affected by government regulation, interest rate changes, financing difficulties, supply and demand of services or fuel, intense competition, natural resource conservation, and commodity price fluctuations. |
| Document Type | 485BPOS |