Investment Risks - American Century Mutual Funds, Inc |
Mar. 01, 2026 |
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| BALANCED FUND | Style Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Style Risk — If at any time the market is not favoring the quantitative investment style used to manage the fund’s equity portion, that portion’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles. |
| BALANCED FUND | Investment Process Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Investment Process Risk — Stocks selected by the portfolio managers using quantitative models may perform differently than expected due to the portfolio managers’ judgments regarding the factors used in the models, the weight placed on each factor, changes from the factors’ historical trends, and technical issues with the construction and implementation of the models (including, for example, data problems and/or software or other implementation issues). There is no guarantee that the use of the quantitative models will result in effective investment decisions for the fund. Additionally, the commonality of portfolio holdings across quantitative investment managers may amplify losses. |
| BALANCED FUND | ESG Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | ESG Risk — Because the fund considers environmental, social, and governance (ESG) data to evaluate a company’s sustainability characteristics in addition to fundamental financial metrics when selecting securities, its portfolio may perform differently than funds that do not consider sustainability characteristics. Sustainability considerations may prioritize long term rather than short term returns. Furthermore, when evaluating sustainability characteristics for securities, portfolio managers may rely on third party sources, which can vary in scope and methodology, and may only take into account one of many sustainability aspects of a portfolio company. Sustainability data used by the portfolio managers often lacks standardization consistency, and also may not be available, complete or accurate. |
| BALANCED FUND | Market Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally. |
| BALANCED FUND | Interest Rate Risk1 Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Interest Rate Risk — Investments in debt securities are sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund’s fixed-income investments are designed to reduce this risk. Interest rate risk, however, is generally higher for the fixed-income portion of the Balanced Fund than for funds that have shorter-weighted maturities, such as money market funds and short-term bond funds. A period of rising interest rates may negatively affect the fund’s performance. |
| BALANCED FUND | Credit Risk1 Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Credit Risk — Debt securities, even investment-grade debt securities, are subject to credit risk. Credit risk is the risk that the inability or perceived inability of the issuer to make interest and principal payments will cause the value of the securities to decrease. As a result the fund’s share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect. |
| BALANCED FUND | Prepayment And Extension Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Prepayment and Extension Risk — The fund may invest in debt securities backed by mortgages or other assets. If these underlying assets are prepaid, the fund may benefit less from declining interest rates than funds of similar maturity that invest less heavily in mortgage- and asset-backed securities. Conversely, an issuer may exercise its right to pay principal on an obligation held by the fund later than expected (extend the obligation) especially in periods of rising interest rates. These events may lengthen the maturity and potentially reduce the value of these securities. |
| BALANCED FUND | Foreign Securities Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Foreign Securities Risk — Foreign securities have certain unique risks, such as currency risk, social, political and economic risk, and foreign market and trading risk. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities. |
| BALANCED FUND | Bank Loan Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Bank Loan Risk — The market for bank loans may not be highly liquid and the fund may have difficulty selling them. Bank loans may not be considered securities, thus the fund may not be afforded anti-fraud protections available under the federal securities laws. In connection with purchasing loan participations, the fund generally will have no right to enforce compliance by borrowers with loan terms nor any set off rights, and the fund may not benefit directly from any posted collateral. As a result, the fund may be subject to the credit risk of both the borrower and the lender selling the participation. Bank loan transactions may take more than seven days to settle, meaning that proceeds would be unavailable to make additional investments or meet redemptions. |
| BALANCED FUND | Collateralized Obligations Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Collateralized Obligations Risk — Collateralized obligations, such as collateralized loan obligations (CLOs), are subject to credit, interest rate, valuation, and prepayment and extension risks. These securities also are subject to risk of default on the underlying asset, particularly during periods of economic downturn. The market value of collateralized obligations may be affected by, among other things, changes in the market value of the underlying assets held by the collateralized obligation, changes in the distributions on the underlying assets, defaults and recoveries on the underlying assets, capital gains and losses on the underlying assets, prepayments on underlying assets and the availability, and prices and interest rates of underlying assets. Lower rated tranches of such debt are subject to a higher risk of total loss and deferral or nonpayment of interest than the more senior tranches to which they are subordinated. Some of the collateralized obligations in which the fund invests may be covenant-lite loans. Covenant-lite loans contain fewer or less restrictive constraints on the borrower. The fund may have fewer rights against a borrower and an accompanying greater risk of loss when it invests in covenant-lite loans. |
| BALANCED FUND | Derivative Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Derivative Risk — The use of derivative instruments involves risks different from, or possibly greater than, the risks associated with investing directly in securities and other traditional instruments. Derivatives are subject to a number of risks, including liquidity, interest rate, market, credit and correlation risk. Derivatives used for hedging or risk management may not operate as intended, may expose the fund to other risks, and may be insufficient to protect the fund from the risks they were intended to hedge. |
| BALANCED FUND | Liquidity Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Liquidity Risk — The fund may also be subject to liquidity risk. During periods of market turbulence or unusually low trading activity, in order to meet redemptions it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund’s share price. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund’s investments. |
| BALANCED FUND | Price Volatility Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term. |
| BALANCED FUND | Risk Lose Money [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund. |
| BALANCED FUND | Risk Not Insured Depository Institution [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. |
| GROWTH FUND | Style Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Style Risk – If at any time the market is not favoring the fund’s growth investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles. |
| GROWTH FUND | Market Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Market Risk – The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally. |
| GROWTH FUND | Foreign Securities Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Foreign Securities Risk – The fund may invest in foreign securities, which can be riskier than investing in U.S. securities. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities. |
| GROWTH FUND | Price Volatility Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Price Volatility Risk – The value of the fund’s shares may fluctuate significantly in the short term. |
| GROWTH FUND | Growth Stocks Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Growth Stocks Risk – Investments in growth stocks may be more volatile than other stocks and the overall stock market. These stocks are typically priced higher than other stocks because of their growth potential, which may or may not be realized. |
| GROWTH FUND | Covered Call Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Covered Call Risk – Writing covered calls may limit the fund’s ability to participate in price increases of the underlying securities and could lower the fund’s return. |
| GROWTH FUND | Diversification Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Diversification Risk – The fund is classified as diversified pursuant to the Investment Company Act, with diversification measured at the time of acquisition of investments. Subsequent market fluctuations may cause the fund to exceed such diversification limits and the fund may hold a greater percentage of its assets in a smaller number of securities. To the extent this occurs, a price change in any one of those securities may have a greater impact on the fund’s share price and the fund may be more volatile. |
| GROWTH FUND | Redemption Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Redemption Risk – The fund may need to sell securities at times it would not otherwise do so in order to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs and/or have adverse tax consequences. Redemption activity can occur for many reasons, including shareholder reactions to market events or product changes. To the extent that a large shareholder (including the advisor, another account advised by the advisor, a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets. |
| GROWTH FUND | Risk Lose Money [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Principal Loss Risk – At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund. |
| GROWTH FUND | Risk Not Insured Depository Institution [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
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| HERITAGE FUND | Style Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Style Risk – If at any time the market is not favoring the fund’s growth investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles. |
| HERITAGE FUND | Market Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Market Risk – The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.
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| HERITAGE FUND | Foreign Securities Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Foreign Securities Risk – The fund may invest in foreign securities, which can be riskier than investing in U.S. securities. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities. |
| HERITAGE FUND | Price Volatility Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Price Volatility Risk – The value of the fund’s shares may fluctuate significantly in the short term. |
| HERITAGE FUND | Growth Stocks Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Growth Stocks Risk – Investments in growth stocks may be more volatile than other stocks and the overall stock market. These stocks are typically priced higher than other stocks because of their growth potential, which may or may not be realized. |
| HERITAGE FUND | Covered Call Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Covered Call Risk – Writing covered calls may limit the fund’s ability to participate in price increases of the underlying securities and could lower the fund’s return. |
| HERITAGE FUND | Redemption Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Redemption Risk –The fund may need to sell securities at times it would not otherwise do so in order to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund’s transaction costs and/or have adverse tax consequences. Redemption activity can occur for many reasons, including shareholder reactions to market events or product changes. To the extent that a large shareholder (including the advisor, another account advised by the advisor, a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets. |
| HERITAGE FUND | Mid Cap Stocks Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Mid Cap Stocks Risk – The fund invests in mid-sized and smaller companies, which may be more volatile and subject to greater risk than larger companies. Smaller companies may have limited financial resources, product lines and markets, and their securities may trade less frequently and in more limited volumes than the securities of larger companies, which could lead to higher transaction costs. |
| HERITAGE FUND | Risk Lose Money [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Principal Loss Risk – At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund. |
| HERITAGE FUND | Risk Not Insured Depository Institution [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
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| LARGE CAP EQUITY FUND | Style Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Style Risk – If at any time the market is not favoring the fund’s investment process, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles. |
| LARGE CAP EQUITY FUND | ESG Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | ESG Risk – Because the fund considers environmental, social, and governance (ESG) data to evaluate a company’s sustainability characteristics in addition to fundamental financial metrics when selecting securities, its portfolio may perform differently than funds that do not consider sustainability characteristics. Sustainability considerations may prioritize long term rather than short term returns. Furthermore, when evaluating sustainability characteristics for securities, portfolio managers may rely on third party sources, which can vary in scope and methodology, and may only take into account one of many sustainability aspects of a portfolio company. Sustainability data used by the portfolio managers often lacks standardization consistency, and also may not be available, complete or accurate. |
| LARGE CAP EQUITY FUND | Market Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Market Risk – The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally. |
| LARGE CAP EQUITY FUND | Foreign Securities Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Foreign Securities Risk – The fund may invest in foreign securities, which can be riskier than investing in U.S. securities. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities. |
| LARGE CAP EQUITY FUND | Redemption Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Redemption Risk – The fund may need to sell securities at times it would not otherwise do so in order to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund's transaction costs and/or have adverse tax consequences. Redemption activity can occur for many reasons, including shareholder reactions to market events or product changes. To the extent that a large shareholder (including the advisor, another account advised by the advisor, a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets. |
| LARGE CAP EQUITY FUND | Benchmark Correlation Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Benchmark Correlation Risk – The fund’s performance will be similar to the performance of its benchmark, the S&P 500® Index. If the fund’s benchmark goes down, it is likely that the fund’s performance will go down. |
| LARGE CAP EQUITY FUND | Risk Lose Money [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Principal Loss Risk – At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund. |
| LARGE CAP EQUITY FUND | Risk Not Insured Depository Institution [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
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| SELECT FUND | Style Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Style Risk – If at any time the market is not favoring the fund’s growth investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles. |
| SELECT FUND | Market Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Market Risk – The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally. |
| SELECT FUND | Foreign Securities Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Foreign Securities Risk – The fund may invest in foreign securities, which can be riskier than investing in U.S. securities. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities. |
| SELECT FUND | Price Volatility Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Price Volatility Risk – The value of the fund’s shares may fluctuate significantly in the short term. |
| SELECT FUND | Growth Stocks Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Growth Stocks Risk – Investments in growth stocks may be more volatile than other stocks and the overall stock market. These stocks are typically priced higher than other stocks because of their growth potential, which may or may not be realized. |
| SELECT FUND | Covered Call Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Covered Call Risk – Writing covered calls may limit the fund’s ability to participate in price increases of the underlying securities and could lower the fund’s return. |
| SELECT FUND | Diversification Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Diversification Risk – The fund is classified as diversified pursuant to the Investment Company Act, with diversification measured at the time of acquisition of investments. Subsequent market fluctuations may cause the fund to exceed such diversification limits and the fund may hold a greater percentage of its assets in a smaller number of securities. To the extent this occurs, a price change in any one of those securities may have a greater impact on the fund’s share price and the fund may be more volatile. |
| SELECT FUND | Risk Lose Money [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Principal Loss Risk – At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund. |
| SELECT FUND | Risk Not Insured Depository Institution [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
|
| SMALL CAP GROWTH FUND | Style Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Style Risk – If at any time the market is not favoring the fund’s growth investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles. |
| SMALL CAP GROWTH FUND | Market Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Market Risk – The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally. |
| SMALL CAP GROWTH FUND | Foreign Securities Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Foreign Securities Risk – The fund may invest in foreign securities, which can be riskier than investing in U.S. securities. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities. |
| SMALL CAP GROWTH FUND | Price Volatility Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Price Volatility Risk – The value of the fund’s shares may fluctuate significantly in the short term. |
| SMALL CAP GROWTH FUND | Growth Stocks Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Growth Stocks Risk – Investments in growth stocks may be more volatile than other stocks and the overall stock market. These stocks are typically priced higher than other stocks because of their growth potential, which may or may not be realized. |
| SMALL CAP GROWTH FUND | Redemption Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Redemption Risk – The fund may need to sell securities at times it would not otherwise do so in order to meet shareholder redemption requests. Selling securities to meet such redemptions may cause the fund to experience a loss, increase the fund's transaction costs and/or have adverse tax consequences. Redemption activity can occur for many reasons, including shareholder reactions to market events or product changes. To the extent that a large shareholder (including the advisor, another account advised by the advisor, a fund of funds or 529 college savings plan) invests in the fund, the fund may experience relatively large redemptions as such shareholder reallocates its assets. |
| SMALL CAP GROWTH FUND | Small Cap Stocks Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Small Cap Stocks Risk – The smaller companies in which the fund invests may be more volatile and subject to greater risk than larger companies. Smaller companies may have limited financial resources, product lines and markets, and their securities may trade less frequently and in more limited volumes than the securities of larger companies, which could lead to higher transaction costs. |
| SMALL CAP GROWTH FUND | Risk Lose Money [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Principal Loss Risk – At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund. |
| SMALL CAP GROWTH FUND | Risk Not Insured Depository Institution [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. |
| ULTRA FUND | Style Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Style Risk — If at any time the market is not favoring the fund’s growth investment style, the fund’s gains may not be as big as, or its losses may be bigger than, those of other equity funds using different investment styles. |
| ULTRA FUND | Market Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Market Risk — The value of the fund’s shares will go up and down based on the performance of the companies whose securities it owns and other factors generally affecting the securities market. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund’s investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally. |
| ULTRA FUND | Foreign Securities Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Foreign Securities Risk — The fund may invest in foreign securities, which can be riskier than investing in U.S. securities. Securities of foreign issuers may be less liquid, more volatile and harder to value than U.S. securities. |
| ULTRA FUND | Price Volatility Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Price Volatility Risk — The value of the fund’s shares may fluctuate significantly in the short term. |
| ULTRA FUND | Growth Stocks Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Growth Stocks Risk — Investments in growth stocks may be more volatile than other stocks and the overall stock market. These stocks are typically priced higher than other stocks because of their growth potential, which may or may not be realized. |
| ULTRA FUND | Covered Call Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Covered Call Risk — Writing covered calls may limit the fund’s ability to participate in price increases of the underlying securities and could lower the fund’s return. |
| ULTRA FUND | Diversification Risk Member | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Diversification Risk — The fund is classified as diversified pursuant to the Investment Company Act, with diversification measured at the time of acquisition of investments. Subsequent market fluctuations may cause the fund to exceed such diversification limits and the fund may hold a greater percentage of its assets in a smaller number of securities. To the extent this occurs, a price change in any one of those securities may have a greater impact on the fund’s share price and the fund may be more volatile. |
| ULTRA FUND | Risk Lose Money [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | Principal Loss Risk — At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund. |
| ULTRA FUND | Risk Not Insured Depository Institution [Member] | |
| Prospectus [Line Items] | |
| Risk [Text Block] | An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. |