PSF Small-Cap Stock Index Portfolio Investment Risks - PSF Small-Cap Stock Index Portfolio	Dec. 31, 2025
Equity Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Equity Securities Risk. The value of a particular stock or equity-related security held by the Portfolio could fluctuate, perhaps greatly, in response to a number of factors, such as changes in the issuer’s financial condition or the value of the equity markets or a sector of those markets. Such events may result in losses to the Portfolio. In addition, due to decreases in liquidity, the Portfolio may be unable to sell its securities holdings within a reasonable time at the price it values the security or at any price.
Small Sized Company Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Small Sized Company Risk. Securities of small sized companies tend to be less liquid than those of larger, more established companies, which can have an adverse effect on the price of these securities and on the Portfolio’s ability to sell these securities. The market price of such investments also may rise more in response to buying demand and fall more in response to selling pressure and be more volatile than investments in larger companies. Investing in issuers within the same market capitalization category carries the risk that the category may be out of favor due to current market conditions or investor sentiment.
Index Tracking Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Index Tracking Risk. The Portfolio’s ability to track the performance and/or holdings and weightings of an index with a high degree of correlation may be affected by, among other things, transaction costs and shareholder purchases and redemptions.
Expense Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Expense Risk. The actual cost of investing in the Portfolio may be higher than the expenses shown in the “Annual Portfolio Operating Expenses” table above for a variety of reasons, including, for example, if the Portfolio’s average net assets decrease.
Liquidity And Valuation Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Liquidity and Valuation Risk. The Portfolio may hold one or more securities for which there are no or few buyers and sellers or the securities are subject to limitations on transfer. The Portfolio may be unable to sell those portfolio holdings at the desired time or price, and may have difficulty determining the value of such securities for the purpose of determining the Portfolio’s net asset value. In such cases, investments owned by the Portfolio may be valued at fair value pursuant to policies and procedures adopted and implemented by the Manager. No assurance can be given that the fair value prices accurately reflect the value of the security. The Portfolio is subject to a liquidity risk management program, which limits the ability of the Portfolio to invest in illiquid investments.
Market And Management Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Market and Management Risk. Markets in which the Portfolio invests may experience volatility and go down in value, and possibly sharply and unpredictably in short periods of time. Investment techniques, risk analyses, and investment strategies, which may include quantitative models or methods, used by a subadviser in making investment decisions for the Portfolio are subject to human error and may not produce the intended or desired results. While a portfolio manager or Subadviser(s) may make efforts to control the risks associated with market changes, and may attempt to identify changes as they occur, market environment changes can be sudden and extreme. The value of the Portfolio’s investments may be negatively affected by the occurrence of domestic or global events, including war, terrorism, significant or unexpected failures, near-failures or credit downgrades of key institutions, unexpected changes in the prices of key commodities, government actions, including the threat of or actual imposition of tariffs, environmental disasters, natural disasters, sanctions, cybersecurity events, supply chain disruptions, political or civil instability, and public health emergencies, among others. Such events may reduce consumer demand or economic output, result in market closures, travel restrictions or quarantines, and significantly adversely impact the economy. These events can disrupt the operations of the Portfolio and its service providers, adversely affect the liquidity and volatility of investments held by the Portfolio, and negatively impact the Portfolio’s performance. There is no guarantee that the investment objective of the Portfolio will be achieved. In periods of market volatility and/or declines, the Portfolio may experience high levels of shareholder redemptions, and may have to sell securities at times when it would otherwise not do so, and at unfavorable prices.
Regulatory Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Regulatory Risk. The Portfolio is subject to a variety of laws and regulations which govern its operations. The Portfolio is subject to regulation by the Securities and Exchange Commission (the SEC) and the Commodity Futures Trading Commission (the CFTC). Similarly, the businesses and other issuers of the securities and other instruments in which the Portfolio invests are also subject to considerable regulation. Changes in laws and regulations may materially impact the Portfolio, a security, business, sector, or market.
Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	The relative significance of the risks summarized below may change over time. All investments have risks to some degree, and it is possible that you could lose money by investing in the Portfolio.
Risk Not Insured Depository Institution [Member]
Prospectus [Line Items]
Risk [Text Block]	An investment in the Portfolio is not a deposit with a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.