Investor A C Institutional Class R [Member] Investment Risks - Investor A, C, Institutional and Class R - BLACKROCK CAPITAL APPRECIATION FUND, INC.	May 31, 2025
Investment Style Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	◼ Investment Style Risk — Under certain market conditions, growth investments have performed better during the later stages of economic expansion. Therefore, this investment style may over time go in and out of favor. At times when the investment style used by the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.
Market Risk and Selection Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	◼ Market Risk and Selection Risk — Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. The value of a security or other asset may decline due to changes in general market conditions, economic trends or events that are not specifically related to the issuer of the security or other asset, or factors that affect a particular issuer or issuers, exchange, country, group of countries, region, market, industry, group of industries, sector or asset class. Local, regional or global events such as war, acts of terrorism, the spread of infectious illness or other public health issues like pandemics or epidemics, recessions, or other events could have a significant impact on the Fund and its investments. Selection risk is the risk that the securities selected by Fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.
Convertible Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	◼ Convertible Securities Risk — The market value of a convertible security performs like that of a regular debt security; that is, if market interest rates rise, the value of a convertible security usually falls. In addition, convertible securities are subject to the risk that the issuer will not be able to pay interest, principal or dividends when due, and their market value may change based on changes in the issuer’s credit rating or the market’s perception of the issuer’s creditworthiness. Since it derives a portion of its value from the common stock into which it may be converted, a convertible security is also subject to the same types of market and issuer risks that apply to the underlying common stock, including the potential for increased volatility in the price of the convertible security.
Information Technology Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	◼ Information Technology Sector Risk — IT companies face intense competition and potentially rapid product obsolescence. They are also heavily dependent on intellectual property rights and may be adversely affected by the loss or impairment of those rights. Companies in the IT sector may face increased government and regulatory scrutiny and may be subject to adverse government or regulatory action. Companies in the software industry may be adversely affected by, among other things, the decline or fluctuation of subscription renewal rates for their products and services and actual or perceived vulnerabilities in their products or services.
Mid Cap Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	◼ Mid Cap Securities Risk — The securities of mid cap companies generally trade in lower volumes and are generally subject to greater and less predictable price changes than the securities of larger capitalization companies.
Operational and Technology Risks [Member]
Prospectus [Line Items]
Risk [Text Block]	◼ Operational and Technology Risks — The Fund is directly and indirectly susceptible to operational and technology risks, including those related to human errors, processing errors, communication errors, systems failures, cybersecurity incidents, and the use of artificial intelligence and machine learning (“AI”), which may result in losses for the Fund and its shareholders or may impair the Fund’s operations. While the Fund’s service providers are required to have appropriate operational, information security and cybersecurity risk management policies and procedures, their methods of risk management may differ from those of the Fund. Operational and technology risks for the issuers in which the Fund invests could also result in material adverse consequences for such issuers and may cause the Fund’s investments in such issuers to lose value.
Preferred Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	◼ Preferred Securities Risk — Preferred securities may pay fixed or adjustable rates of return. Preferred securities are subject to issuer-specific and market risks applicable generally to equity securities. In addition, a company’s preferred securities generally pay dividends only after the company makes required payments to holders of its bonds and other debt. For this reason, the value of preferred securities will usually react more strongly than bonds and other debt to actual or perceived changes in the company’s financial condition or prospects. Preferred securities of smaller companies may be more vulnerable to adverse developments than preferred securities of larger companies.
Rights Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	◼ Rights Risk — The failure to exercise subscription rights to purchase common stock would result in the dilution of the Fund’s interest in the issuing company. The market for such rights is not well developed, and, accordingly, the Fund may not always realize full value on the sale of rights.
Risk of Investing in the United States [Member]
Prospectus [Line Items]
Risk [Text Block]	◼ Risk of Investing in the United States — Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure.
Equity Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	◼ Equity Securities Risk — Stock markets are volatile. The price of equity securities fluctuates based on changes in a company’s financial condition and overall market and economic conditions.
Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	You may lose part or all of yourinvestment in the Fund or your investment may not perform as well as other similar investments.
Risk Not Insured Depository Institution [Member]
Prospectus [Line Items]
Risk [Text Block]	An investment in theFund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any othergovernment agency.

Investor A C Institutional Class R [Member] Investment Risks - Investor A, C, Institutional and Class R - BLACKROCK CAPITAL APPRECIATION FUND, INC.

May 31, 2025

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Investment Style Risk — Under certain market conditions, growth investments have performed better during the later stages of economic expansion. Therefore, this investment style may over time go in and out of favor. At times when the investment style used by the Fund is out of favor, the Fund may underperform other equity funds that use different investment styles.

Market Risk and Selection Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

◼

Market Risk and Selection Risk — Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. The value of a security or other asset may decline due to changes in general market conditions, economic trends or events that are not specifically related to the issuer of the security or other asset, or factors that affect a particular issuer or issuers, exchange, country, group of countries, region, market, industry, group of industries, sector or asset class. Local, regional or global events such as war, acts of terrorism, the spread of infectious illness or other public health issues like pandemics or epidemics, recessions, or other events could have a significant impact on the Fund and its investments. Selection risk is the risk that the securities selected by Fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

Convertible Securities Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

◼

Convertible Securities Risk — The market value of a convertible security performs like that of a regular debt security; that is, if market interest rates rise, the value of a convertible security usually falls. In addition, convertible securities are subject to the risk that the issuer will not be able to pay interest, principal or dividends when due, and their market value may change based on changes in the issuer’s credit rating or the market’s perception of the issuer’s creditworthiness. Since it derives a portion of its value from the common stock into which it may be converted, a convertible security is also subject to the same types of market and issuer risks that apply to the underlying common stock, including the potential for increased volatility in the price of the convertible security.

Information Technology Sector Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

◼

Information Technology Sector Risk — IT companies face intense competition and potentially rapid product obsolescence. They are also heavily dependent on intellectual property rights and may be adversely affected by the loss or impairment of those rights. Companies in the IT sector may face increased government and regulatory scrutiny and may be subject to adverse government or regulatory action. Companies in the software industry may be adversely affected by, among other things, the decline or fluctuation of subscription renewal rates for their products and services and actual or perceived vulnerabilities in their products or services.

Mid Cap Securities Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

◼

Mid Cap Securities Risk — The securities of mid cap companies generally trade in lower volumes and are generally subject to greater and less predictable price changes than the securities of larger capitalization companies.

Operational and Technology Risks [Member]

Prospectus [Line Items]

Risk [Text Block]

◼

Operational and Technology Risks — The Fund is directly and indirectly susceptible to operational and technology risks, including those related to human errors, processing errors, communication errors, systems failures, cybersecurity incidents, and the use of artificial intelligence and machine learning (“AI”), which may result in losses for the Fund and its shareholders or may impair the Fund’s operations. While the Fund’s service providers are required to have appropriate operational, information security and cybersecurity risk management policies and procedures, their methods of risk management may differ from those of the Fund. Operational and technology risks for the issuers in which the Fund invests could also result in material adverse consequences for such issuers and may cause the Fund’s investments in such issuers to lose value.

Preferred Securities Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

◼

Preferred Securities Risk — Preferred securities may pay fixed or adjustable rates of return. Preferred securities are subject to issuer-specific and market risks applicable generally to equity securities. In addition, a company’s preferred securities generally pay dividends only after the company makes required payments to holders of its bonds and other debt. For this reason, the value of preferred securities will usually react more strongly than bonds and other debt to actual or perceived changes in the company’s financial condition or prospects. Preferred securities of smaller companies may be more vulnerable to adverse developments than preferred securities of larger companies.

Rights Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

◼

Rights Risk — The failure to exercise subscription rights to purchase common stock would result in the dilution of the Fund’s interest in the issuing company. The market for such rights is not well developed, and, accordingly, the Fund may not always realize full value on the sale of rights.

Risk of Investing in the United States [Member]

Prospectus [Line Items]

Risk [Text Block]

◼

Risk of Investing in the United States — Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure.

Equity Securities Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

◼

Equity Securities Risk — Stock markets are volatile. The price of equity securities fluctuates based on changes in a company’s financial condition and overall market and economic conditions.

Risk Lose Money [Member]

Prospectus [Line Items]

Risk [Text Block]

You may lose part or all of yourinvestment in the Fund or your investment may not perform as well as other similar investments.

Risk Not Insured Depository Institution [Member]

Prospectus [Line Items]

Risk [Text Block]

An investment in theFund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any othergovernment agency.