Investment Strategy |
Dec. 31, 2025 |
|---|---|
| Midcap Stock Portfolio | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategy |
| Strategy Narrative [Text Block] | To pursue its goal, the fund normally invests at least 80% of its net assets, plus any borrowings for investment purposes, in stocks of mid-cap companies. The fund currently considers "mid-cap companies" to be those companies with market capitalizations, at the time of purchase, within the market capitalization range of companies comprising the S&P MidCap 400 Index. The fund invests in growth and value stocks, which are chosen through a disciplined investment process that combines computer modeling techniques, fundamental analysis and risk management. Consistency of returns compared to the S&P MidCap 400 Index is a primary goal of the fund's investment process. The fund's sub-adviser, Newton Investment Management North America, LLC, an affiliate of BNY Mellon Investment Adviser, Inc., selects stocks through a "bottom-up," structured approach that seeks to identify undervalued securities using a quantitative ranking process. The process is driven by a proprietary quantitative model that measures a diverse set of corporate characteristics to identify and rank stocks based on valuation, momentum and sentiment and earnings quality measures. Next, the fund's sub-adviser constructs the portfolio through a risk controlled process, focusing on stock selection as opposed to making proactive decisions as to industry and sector exposure. The fund seeks to maintain a portfolio that has exposure to industries and market capitalizations that are generally similar to those of the S&P MidCap 400 Index. Finally, within each sector and style subset, the fund seeks to overweight the stocks that have been ranked most attractive and underweight or not hold the stocks that have been ranked least attractive. The fund's sub-adviser monitors the holdings in the fund's portfolio, and considers selling a security if the company's relative attractiveness deteriorates or if valuation becomes excessive. The fund also may sell a security if an event occurs that contradicts the sub-adviser's rationale for purchasing it, such as deterioration in the company's fundamentals. In addition, the fund may sell a security if the sub-adviser determines better investment opportunities emerge elsewhere. |
| Small Cap Stock Index Portfolio | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategy |
| Strategy Narrative [Text Block] | To pursue its goal, the fund generally is fully invested in all of the stocks that comprise the S&P SmallCap 600 Index. The fund generally invests in all of the stocks in the index in proportion to their weighting in the index; however, at times, the fund may invest in a representative sample of stocks included in the index and in futures whose performance is tied to the index. Under these circumstances, the fund expects to invest in approximately 500 or more of the stocks in the index. Because the fund has expenses, performance will tend to be slightly lower than that of the S&P SmallCap 600 Index. The fund attempts to have a correlation between its performance and that of the S&P SmallCap 600 Index of at least .95, before fees and expenses. A correlation of 1.00 would mean that the fund and the index were perfectly correlated. The S&P SmallCap 600 Index is an unmanaged index of the common stocks of 600 small-sized companies in the U.S. Standard & Poor's weights each company's stock in the index by its market capitalization (i.e., the share price times the number of shares outstanding), adjusted by the number of available float shares (i.e., those shares available to public investors). As of February 2026, companies eligible to be included in the S&P SmallCap 600 Index generally have market capitalizations ranging between approximately $1.2 billion and $8.0 billion. The fund will concentrate its investments (i.e., hold 25% or more of its total assets) in a particular industry or group of industries to approximately the same extent that the index is concentrated. In addition, to the extent the fund purchases securities comprising the SmallCap 600® Index, the fund may, from time to time, invest a significant portion of its assets in securities of companies in certain sectors. "Standard & Poor's®," "S&P®" and "S&P SmallCap 600® Index" are trademarks of Standard & Poor's Financial Services LLC and have been licensed for use by the fund. The fund is not sponsored, endorsed, sold or promoted by Standard & Poor's and Standard & Poor's makes no representation regarding the advisability of investing in the fund. |
| Technology Growth Portfolio | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategy |
| Strategy Narrative [Text Block] | To pursue its goal, the fund normally invests at least 80% of its net assets, plus any borrowings for investment purposes, in the stocks of growth companies of any size that the fund's sub-adviser, Newton Investment Management North America, LLC, an affiliate of BNY Mellon Investment Adviser, Inc., believes to be leading producers or beneficiaries of technological innovation. In choosing stocks, the fund's sub-adviser looks for technology companies with the potential for strong earnings or revenue growth rates. The fund's investment process centers on a multi-dimensional approach that looks for opportunities across emerging, cyclical or stable growth companies. The fund's investment approach seeks companies that appear to have strong earnings momentum, positive earnings revisions, favorable growth, product or market cycles and/or favorable valuations. Up to 25% of the fund's assets may be invested in foreign securities. The fund typically sells a stock when the fund's sub-adviser believes there is a more attractive alternative, or there are deteriorating fundamentals, such as a loss of competitive advantage, a failure in management execution or deteriorating capital structure. The fund also may sell stocks when the sub-adviser's evaluation of a sector has changed. |