Small Cap Index Fund Investment Risks - Small Cap Index Fund	May 31, 2026
Equity Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Equity Securities Risk. The Fund’s investments in equity securities are subject to the risk that stock prices will fall and may underperform other asset classes. Individual stock prices fluctuate from day-to-day and may decline significantly. The prices of individual stocks may be negatively affected by poor company results or other factors affecting individual prices, as well as industry and/or economic trends and developments affecting industries or the securities market as a whole.
Index Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Index Risk. In attempting to track the performance of the index, the Fund may be more susceptible to adverse developments concerning a particular security, company or industry because the Fund generally will not use any defensive strategies to mitigate its risk exposure.
Failure to Match Index Performance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Failure to Match Index Performance Risk. The ability of the Fund to match the performance of the Index may be affected by, among other things, changes in securities markets, the manner in which performance of the Index is calculated, changes in the composition of the Index, the amount and timing of cash flows into and out of the Fund, commissions, portfolio expenses, and any differences in the pricing of securities by the Fund and the Index. When the Fund employs an “optimization” strategy, the Fund is subject to an increased risk of tracking error, in that the securities selected in the aggregate for the Fund may perform differently than the Index.
Small Cap Company Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Small-Cap Company Risk. Investing in small-cap companies carries the risk that due to current market conditions these companies may be out of favor with investors. Small companies often are in the early stages of development with limited product lines, markets, or financial resources and managements lacking depth and experience, which may cause their stock prices to be more volatile than those of larger companies. Small company stocks may be less liquid yet subject to abrupt or erratic price movements. It may take a substantial period of time before the Fund realizes a gain on an investment in a small-cap company, if it realizes any gain at all.
Derivatives Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Derivatives Risk. The prices of derivatives may move in unexpected ways due to the use of leverage and other factors and may result in increased volatility or losses. The Fund may not be able to terminate or sell derivative positions, and a liquid secondary market may not always exist for derivative positions.
Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Market Risk. The Fund’s share price can fall because of weakness in the broad market, a particular industry, or specific holdings or due to adverse social, political or economic developments here or abroad, changes in investor psychology, technological disruptions, or heavy institutional selling and other conditions or events (including, for example, military confrontations, war, terrorism, trade wars, disease/virus outbreaks and epidemics). The prices of individual securities may fluctuate, sometimes dramatically, from day to day. The prices of stocks and other equity securities tend to be more volatile than those of fixed-income securities.
Securities Lending Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Securities Lending Risk. Engaging in securities lending could increase the market and credit risk for Fund investments. The Fund may lose money if it does not recover borrowed securities, the value of the collateral falls, or the value of investments made with cash collateral declines. The Fund’s loans will be collateralized by securities issued or guaranteed by the U.S. Government or its agencies and instrumentalities, which subjects the Fund to the credit risk of the U.S. Government or the issuing federal agency or instrumentality. If the value of either the cash collateral or the Fund’s investments of the cash collateral falls below the amount owed to a borrower, the Fund also may incur losses that exceed the amount it earned on lending the security. Securities lending also involves the risks of delay in receiving additional collateral or possible loss of rights in the collateral if the borrower fails. Another risk of securities lending is the risk that the loaned portfolio securities may not be available to the Fund on a timely basis and the Fund may therefore lose the opportunity to sell the securities at a desirable price.
Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	If the value of the assets of the Fund goes down, you could lose money.
Risk Not Insured Depository Institution [Member]
Prospectus [Line Items]
Risk [Text Block]	Shares of the Fund are not bank deposits and are not guaranteed or insured by any bank, government entity or the Federal Deposit Insurance Corporation.

Small Cap Index Fund Investment Risks - Small Cap Index Fund

May 31, 2026

Equity Securities Risk. The Fund’s investments in equity securities are subject to the risk that stock prices will fall and may underperform other asset classes. Individual stock prices fluctuate from day-to-day and may decline significantly. The prices of individual stocks may be negatively affected by poor company results or other factors affecting individual prices, as well as industry and/or economic trends and developments affecting industries or the securities market as a whole.

Prospectus [Line Items]

Risk [Text Block]

Index Risk. In attempting to track the performance of the index, the Fund may be more susceptible to adverse developments concerning a particular security, company or industry because the Fund generally will not use any defensive strategies to mitigate its risk exposure.

Failure to Match Index Performance Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

Failure to Match Index Performance Risk. The ability of the Fund to match the performance of the Index may be affected by, among other things, changes in securities markets, the manner in which performance of the Index is calculated, changes in the composition of the Index, the amount and timing of cash flows into and out of the Fund, commissions, portfolio expenses, and any differences in the pricing of securities by the Fund and the Index. When the Fund employs an “optimization” strategy, the Fund is subject to an increased risk of tracking error, in that the securities selected in the aggregate for the Fund may perform differently than the Index.

Small Cap Company Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

Small-Cap Company Risk. Investing in small-cap companies carries the risk that due to current market conditions these companies may be out of favor with investors. Small companies often are in the early stages of development with limited product lines, markets, or financial resources and managements lacking depth and experience, which may cause their stock prices to be more volatile than those of larger companies. Small company stocks may be less liquid yet subject to abrupt or erratic price movements. It may take a substantial period of time before the Fund realizes a gain on an investment in a small-cap company, if it realizes any gain at all.

Derivatives Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

Derivatives Risk. The prices of derivatives may move in unexpected ways due to the use of leverage and other factors and may result in increased volatility or losses. The Fund may not be able to terminate or sell derivative positions, and a liquid secondary market may not always exist for derivative positions.

Market Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

Market Risk. The Fund’s share price can fall because of weakness in the broad market, a particular industry, or specific holdings or due to adverse social, political or economic developments here or abroad, changes in investor psychology, technological disruptions, or heavy institutional selling and other conditions or events (including, for example, military confrontations, war, terrorism, trade wars, disease/virus outbreaks and epidemics). The prices of individual securities may fluctuate, sometimes dramatically, from day to day. The prices of stocks and other equity securities tend to be more volatile than those of fixed-income securities.

Securities Lending Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

Securities Lending Risk. Engaging in securities lending could increase the market and credit risk for Fund investments. The Fund may lose money if it does not recover borrowed securities, the value of the collateral falls, or the value of investments made with cash collateral declines. The Fund’s loans will be collateralized by securities issued or guaranteed by the U.S. Government or its agencies and instrumentalities, which subjects the Fund to the credit risk of the U.S. Government or the issuing federal agency or instrumentality. If the value of either the cash collateral or the Fund’s investments of the cash collateral falls below the amount owed to a borrower, the Fund also may incur losses that exceed the amount it earned on lending the security. Securities lending also involves the risks of delay in receiving additional collateral or possible loss of rights in the collateral if the borrower fails. Another risk of securities lending is the risk that the loaned portfolio securities may not be available to the Fund on a timely basis and the Fund may therefore lose the opportunity to sell the securities at a desirable price.

Risk Lose Money [Member]

Prospectus [Line Items]

Risk [Text Block]

If the value of the assets of the Fund goes down, you could lose money.

Risk Not Insured Depository Institution [Member]

Prospectus [Line Items]

Risk [Text Block]

Shares of the Fund are not bank deposits and are not guaranteed or insured by any bank, government entity or the Federal Deposit Insurance Corporation.