Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	THE ALGER FUNDS
Prospectus Date	rr_ProspectusDate	Apr. 01, 2024
Class A C Shares | Alger Artificial Intelligence Fund - AC
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<span style="color:#262626;font-family:Arial;font-size:10pt;font-weight:bold;text-transform:uppercase;">Alger AI Enablers & Adopters Fund</span>
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#0065D2;font-family:Arial;font-size:10pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Alger AI Enablers & Adopters Fund seeks long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	<span style="color:#0065D2;font-family:Arial;font-size:10pt;font-weight:bold;">Fund Fees and Expenses</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and examples below.You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in Class A Shares of the Alger Family of Funds, including the Fund. More information about these and other discounts is available from your financial professional and in “Purchasing and Redeeming Fund Shares” on page 19 and in Appendix A – Waivers and Discounts Available from Intermediaries on page A-1 in the Fund’s Prospectus, and in the sections “Right of Accumulation (Class A Shares)” and “Letter of Intent (Class A)” beginning on page 30 of the Fund’s Statement of Additional Information.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#262626;font-family:Arial;font-size:9pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#262626;font-family:Arial;font-size:9pt;margin-left:0%;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#262626;font-family:Arial;font-size:9pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#262626;font-family:Arial;font-size:9pt;margin-left:0%;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="color:#262626;font-family:Arial;font-size:8pt;">October 31, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#0065D2;font-family:Arial;font-size:10pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. No portfolio turnover rate is included for the Fund because the Fund has not yet commenced operations.
Expenses Deferred Charges [Text Block]	rr_ExpensesDeferredChargesTextBlock	Purchases of $1 million or more of Class A Shares at net asset value may be subject to a contingent deferred sales charge of 1.00% on redemptions made within 12 months of purchase.
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	<span style="color:#262626;font-family:Arial;font-size:9pt;">You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least </span><span style="color:#262626;font-family:Arial;font-size:9pt;">$25,000</span><span style="color:#262626;font-family:Arial;font-size:9pt;"> in Class A Shares of the Alger Family of Funds, including the Fund.</span>
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	$ 25,000
Other Expenses, New Fund, Based on Estimates [Text]	rr_OtherExpensesNewFundBasedOnEstimates	<span style="color:#262626;font-family:Arial;font-size:8pt;">“Other Expenses” are based on estimated amounts for the current fiscal year. Actual expenses may differ from estimates.</span>
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#0065D2;font-family:Arial;font-size:9pt;font-weight:bold;">Example</span>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The following examples are intended to help you compare the cost of investing in the Fund with the cost of investing in other funds. The examples assume that you invest $10,000 in the Fund for the time periods indicated, that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. The one-year example and the period of the three-year example through October 31, 2025 are based on net operating expenses, which reflect the contractual expense limitation agreed to by the Manager. Although your actual costs may be higher or lower, based on these assumptions you would pay the following expenses if you redeemed your shares at the end of each period:
Expense Example, No Redemption, By Year, Caption [Text]	rr_ExpenseExampleNoRedemptionByYearCaption	<span style="color:#262626;font-family:Arial;font-size:8pt;font-weight:bold;margin-left:36pt;">You would pay the following expenses if you did not redeem your shares:</span>
Strategy [Heading]	rr_StrategyHeading	<span style="color:#0065D2;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Investment Strategy</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Manager believes companies undergoing Positive Dynamic Change offer the best opportunities and demonstrate promising growth potential. Positive Dynamic Change refers to companies realizing High Unit Volume Growth or companies undergoing Positive Lifecycle Change. High Unit Volume Growth companies are traditional growth companies experiencing, for example, rapidly growing demand or market dominance. Positive Lifecycle Change companies are, for example, companies benefitting from new regulations, a new product innovation or new management.Under normal circumstances, the Fund invests at least 80% of its net assets, plus any borrowings for investment purposes, in equity securities of companies of any market capitalization that it believes will benefit from artificial intelligence (“AI”),demonstrate promising growth potential, and are companies where AI can play a material role in potentially driving stock price performance over the next twelve to thirty-six months. Equity securities include common or preferred stocks listed on U.S. or foreign exchanges.In effecting the Fund’s investment strategy, the Manager initially employs its fundamental, proprietary investment research investment process to identify companies undergoing Positive Dynamic Change.Next, the Manager determines whether it believes such companies benefit from AI by classifying them into two categories: AI Enablers and AI Adopters. AI Enablers include companies developing the building block components for and investing in AI infrastructure such as machinery, hardware, software and services. AI Adopters include companies that integrate AI into theirbusinesses to enhance their products or services or make their operations more productive. These categories may be adjusted from time to time to incorporate future developments as the area of AI evolves.Lastly, the Manager determines whether AI can play a material role in potentially driving stock performance over the next twelve to thirty-six months through its fundamental research process. The Manager makes this determination using mainly qualitative assessments to reach its conclusions due to the Manager’s view that publicly traded companies, even those focused upon AI, are not universally transparent in sharing their exposure to AI. Specifically, the Manager makes assessments based upon its knowledge of each company’s creation, distribution and/or consumption of AI products and services, and to the extent available, upon quantitative factors including but not limited to a company’s revenue derived from, and/or resources devoted to, AI. In assessing what material role AI may play in potentially driving stock performance over the next twelve to thirty-six months, the Manager considers from among the following criteria with respect to AI Enablers, estimates of a company’s future market share in AI-related infrastructure services, product and/or service quality, acceleration of revenue growth and rate of adoption relative to peers, and, with respect to AI Adopters, estimates of the degree of AI integration into a company’s operations, the resulting impact on reducing a company’s costs, the increase in efficiency of the company’s operations, the potential enhancement to a company’s net earnings and revenue growth, improvement of product or service offerings, and the extent to which a company may gain a potential competitive advantage from AI within its industry.The Fund will invest at least 25% of its total assets in companies focused in the following group of related industries: software, technology hardware storage and peripherals, semiconductors and semiconductor equipment, information technology services, electronic equipment instruments and components, communications equipment, broadline retail and interactive media and services, as classified by third party sources. From time to time, the Fund may have 25% or more of its total assets invested in any one of these industries.The Fund may invest a substantial portion of its assets in a smaller number of issuers. As a result, the Fund is a non-diversified investment company, which means the performance results of any one position may have a greater impact on the Fund’s performance.The Fund’s investments include small-, medium- and large-capitalization companies. The Fund may invest in foreign securities listed on foreign exchanges as well as American Depositary Receipts (“ADRs”) and Global Depositary Receipts (“GDRs”).The Fund may sell a stock when it reaches a target price, it fails to perform as expected, or other opportunities appear more attractive. As a result, the Fund may engage in active trading of portfolio securities.The Fund may invest a significant portion of its assets in securities of companies conducting business within a single sector, as defined by third party sources. For the purpose of categorizing companies, sectors are a broader category than industries and industries comprise sectors.The Fund invests in cash (and cash equivalents) when the Fund is unable to find enough attractive long-term investments to meet its investment objective, to meet redemptions and/or when the Manager believes it is advisable to do so during times of short-term market volatility. During these times, cash (and cash equivalents) will not exceed 15% of the Fund’s net assets.
Risk [Heading]	rr_RiskHeading	<span style="color:#0065D2;font-family:Arial;font-size:10pt;font-weight:bold;">Principal Risks</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#0065D2;font-family:Arial;font-size:10pt;font-weight:bold;">Performance</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	No performance information will be presented until the Fund has been in operation for a full calendar year. Annual performance information gives some indication of the risks of an investment in the Fund by comparing the Fund’s performance with a broad measure of market performance. The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance information is available on the Fund’s website at www.alger.com.
Performance One Year or Less [Text]	rr_PerformanceOneYearOrLess	<span style="color:#262626;font-family:Arial;font-size:9pt;">No performance information will be presented until the Fund has been in operation for a full calendar year.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="color:#262626;font-family:Arial;font-size:9pt;">www.alger.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#262626;font-family:Arial;font-size:9pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the </span><span style="color:#262626;font-family:Arial;font-size:9pt;">Fund will perform in the future.</span>
Class A C Shares | Alger Artificial Intelligence Fund - AC | Risk Nondiversified Status [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Non-Diversification Risk – The Fund is a non-diversified investment company. Therefore, the Fund’s performance may be more vulnerable to changes in the market value of a single issuer and more susceptible to risks associated with a single economic, political, or regulatory occurrence than a fund that has a diversified portfolio.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	The Fund’s share price may go down, which means you could lose money.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	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.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Investment Risk – An investment in the Fund is subject to investment risk, including the possible loss of the entire principal amount that you invest.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Market Risk – Your investment in Fund shares represents an indirect investment in the securities owned by the Fund. The value of these securities, like other investments, may move up or down, sometimes rapidly and unpredictably. Your Fund shares at any point in time may be worth less than what you invested, even after taking into account the reinvestment of Fund dividends and distributions. Local, regional or global events such as environmental or natural disasters, war, terrorism, pandemics, outbreaks of infectious diseases, and similar public health threats, recessions, or other events could have a significant impact on the Fund and its investments.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Equity Securities Risk – As with any fund that invests in stocks, your investment will fluctuate in value, and the loss of your investment is a risk of investing. The Fund’s price per share will fluctuate due to changes in the market prices of its investments. Also, the Fund’s investments may not grow as fast as the rate of inflation and stocks tend to be more volatile than some other investments you could make, such as bonds.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Artificial Intelligence Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Artificial Intelligence Risk – Companies involved in, or exposed to, AI-related businesses may have limited product lines, markets, financial resources or personnel. These companies face intense competition and potentially rapid product obsolescence, and many depend significantly on retaining and growing the consumer base of their respective products and services. Many of these companies are also reliant on the end-user demand of products and services in various industries that may in part utilize AI. Further, many companies involved in, or exposed to, AI-related businesses may be substantially exposed to the market and business risks of other industries or sectors, and the Fund may be adversely affected by negative developments impacting those companies, industries or sectors. In addition, these companies are heavily dependent on intellectual property rights and may be adversely affected by loss or impairment of those rights. There can be no assurance that companies involved in AI will be able to successfully protect their intellectual property to prevent the misappropriation of their technology, or that competitors will not develop technology that is substantially similar or superior to such companies’ technology.Companies that utilize AI in their business operations, and the challenges with properly managing AI’s use could result in reputational harm, competitive harm, and legal liability, and/or an adverse effect on such companies’ business operations. If the content, analyses, or recommendations that AI applications assist companies in producing are or are alleged to be deficient, inaccurate, or biased, the Fund may be adversely affected. Additionally, AI tools used by such companies may produce inaccurate, misleading or incomplete responses that could lead to errors in decision-making or other business activities, which could have a negative impact on the performance of such companies. Such AI tools could also be used against companies in criminal or negligent ways.AI technology could face increasing regulatory scrutiny in the future, which may limit the development of this technology and impede the growth of companies that develop and/or utilize this technology. Similarly, the collection of data from consumers and other sources could face increased scrutiny as regulators consider how the data is collected, stored, safeguarded and used. AI companies may face regulatory fines and penalties, including potential forced break-ups, that could hinder the ability of the companies to operate on an ongoing basis. Country, government, and/or region-specific regulations or restrictions could have an impact on AI and big data companies.AI companies typically engage in significant amounts of spending on research and development, and there is no guarantee that the products or services produced by these companies will be successful. AI companies, especially smaller companies, tend to be more volatile than companies that do not rely heavily on technology.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Growth Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Growth Securities Risk – Prices of growth stocks tend to be higher in relation to their companies’ earnings and may be more sensitive to market, political and economic developments than other stocks, making their prices more volatile. An investment in the Fund may be better suited to investors who seek long-term capital growth and can tolerate fluctuations in their investment’s value.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Concentration Risk – By focusing on an industry or a group of industries, the Fund carries much greater risks of adverse developments and price movements in such industries than a fund that invests in a wider variety of industries. Because the Fund concentrates in a specific industry or group of industries, there is also the risk that the Fund will perform poorly during a slump in demand for securities of companies in such industries.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Mid Cap Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Mid Cap Securities Risk – There may be greater risk in investing in medium-capitalization companies rather than larger, more established companies due to such factors as inexperienced management and limited product lines or financial resources. It may also be difficult or impossible to liquidate a security position at a time and price acceptable to the Fund because of the potentially less frequent trading of stocks of smaller market capitalization.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Small Cap Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Small Cap Securities Risk – There may be greater risk in investing in companies with small market capitalizations rather than larger, more established companies owing to such factors as more limited product lines or financial resources or lack of management depth. It may also be difficult or impossible to liquidate a security position at a time and price acceptable to the Fund because of the potentially less frequent trading of stocks of smaller market capitalization.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Sector Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Sector Risk – The Fund may have a significant portion of its assets invested in securities of companies conducting business within a single sector, as defined by third party sources. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than a fund that has a more diversified portfolio. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Foreign Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Foreign Securities Risk – The Fund’s performance will be influenced by political, social and economic factors affecting investments in foreign companies. Special risks associated with investments in foreign companies include exposure to currency fluctuations, lack of liquidity, potential for market manipulation, less developed or less efficient trading markets, limited access to reliable capital, lack of comprehensive company information, political instability, differing audit, regulatory, and legal standards and lack of financial reporting standards.
Class A C Shares | Alger Artificial Intelligence Fund - AC | ADR and GDR Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	ADR and GDR Risk – ADRs and GDRs may be subject to some of the same risks as direct investment in foreign companies, which includes international trade, currency, political, regulatory and diplomatic risks. In a sponsored ADR arrangement, the foreign issuer assumes the obligation to pay some or all of the depository’s transaction fees. Unsponsored ADRs and GDRs are organized independently and without the cooperation of the foreign issuer of the underlying securities, and involve additional risks because U.S. reporting requirements do not apply. In addition, the issuing bank may deduct shareholder distribution, custody, foreign currency exchange, and other fees from the payment of dividends. GDRs can involve additional currency risk since, unlike ADRs, they may not be U.S. Dollar-denominated.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Portfolio Turnover Active Trading Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Portfolio Turnover (Active Trading) Risk – Because the Fund may engage in active trading of portfolio securities, it may incur increased transaction costs and brokerage commissions, both of which can lower the actual return on an investment. Active trading may also increase short-term gains and losses, which may affect the taxes a shareholder has to pay.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Cash Position Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	Cash Position Risk – At times, the Fund may hold up to 15% of its net assets in cash (and cash equivalents), which may underperform relative to equity securities.
Class A C Shares | Alger Artificial Intelligence Fund - AC | Class C
Risk Return Abstract	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases as a % of offering price	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum deferred sales charge (load) as a % of purchase price or redemption proceeds, whichever is lower	rr_MaximumDeferredSalesChargeOverOfferingPrice	1.00%
Advisory Fees	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses	rr_OtherExpensesOverAssets	0.61%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.06%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.51%)	[2]
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	rr_NetExpensesOverAssets	1.55%
1 Year	rr_ExpenseExampleYear01	$ 258
3 Years	rr_ExpenseExampleYear03	566
1 Year	rr_ExpenseExampleNoRedemptionYear01	158
3 Years	rr_ExpenseExampleNoRedemptionYear03	$ 566
Class A C Shares | Alger Artificial Intelligence Fund - AC | Class A
Risk Return Abstract	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases as a % of offering price	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	5.25%
Maximum deferred sales charge (load) as a % of purchase price or redemption proceeds, whichever is lower	rr_MaximumDeferredSalesChargeOverOfferingPrice	none	[3]
Advisory Fees	rr_ManagementFeesOverAssets	0.45%
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.61%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.31%
Fee Waiver and/or Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.51%)	[2]
Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement	rr_NetExpensesOverAssets	0.80%
1 Year	rr_ExpenseExampleYear01	$ 602
3 Years	rr_ExpenseExampleYear03	$ 841

[1] “Other Expenses” are based on estimated amounts for the current fiscal year. Actual expenses may differ from estimates.

[2] Fred Alger Management, LLC (the “Manager”) has contractually agreed to waive and/or reimburse Fund expenses (excluding acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through October 31, 2025 to the extent necessary to limit other expenses and any other applicable share class-specific expenses of the Class A Shares and Class C Shares of the Fund to 0.35% and 1.10%, respectively, of each class’s average daily net assets. This expense reimbursement may only be amended or terminated prior to its expiration date by agreement between the Manager and the Fund’s Board of Trustees, and will terminate automatically in the event of termination of the Investment Advisory Agreement. The Manager may recoup any fees waived or expenses reimbursed pursuant to the contract; however, the Fund will only make repayments to the Manager if such repayment does not cause the Fund’s expense ratio after the repayment is taken into account, to exceed both (i) the expense cap in place at the time such amounts were waived or reimbursed, and (ii) the Fund’s current expense cap. Such recoupment is limited to two years from the date the amount is initially waived or reimbursed.

[3] Purchases of $1 million or more of Class A Shares at net asset value may be subject to a contingent deferred sales charge of 1.00% on redemptions made within 12 months of purchase.