Objective, Primary [Text Block]

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Fund OverviewKey Facts About BlackRock China A Opportunities Fund

Objective [Heading]

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Investment Objective

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The investment objective of BlackRock China A Opportunities Fund (the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek to maximize total return. Total return means the combination of capital appreciation and investment income.

Expense [Heading]

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Fees and Expenses of the Fund

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy, hold and sell Class K Shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to your financial professional or your selected securities dealer, broker, investment adviser, service provider or industry professional (including BlackRock Advisors, LLC (“BlackRock”) and its affiliates) (each, a “Financial Intermediary”), which are not reflected in the table and example below.

Operating Expenses Caption [Text]

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Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

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June 30, 2026

Portfolio Turnover [Heading]

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Portfolio Turnover:

Portfolio Turnover [Text Block]

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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 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. During the most recent fiscal year, the Fund’s portfolio turnover rate was 149% of the average value of its portfolio.

Portfolio Turnover, Rate

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149.00%

Expense Example [Heading]

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Example:

Expense Example Narrative [Text Block]

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This Example is intended to help you compare the cost of investing in shares of the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

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Principal Investment Strategies of the Fund

Strategy Narrative [Text Block]

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Under normal circumstances, the Fund seeks to invest at least 80% of its net assets plus the amount of any borrowings for investment purposes in equity securities of issuers domiciled in the People’s Republic of China (“China” or the “PRC” and, for the purpose of this prospectus, excluding Hong Kong, Macau and Taiwan) and listed in China (i.e., A-shares), and derivatives that have similar economic characteristics to such securities. “A-shares” are equity securities of companies domiciled in China that trade on the Shanghai Stock Exchange (“SSE”) and the Shenzhen Stock Exchange (“SZSE”) and are quoted in renminbi (“RMB”).

The Fund primarily intends to invest in equity securities or other financial instruments that are components of, or have characteristics similar to, the securities included in the MSCI China A Onshore Index. The MSCI China A Onshore Index captures large and mid-cap representation across China securities listed on the SSE and SZSE. The index includes those securities that are accessible through the Shanghai-Hong Kong Stock Connect program (“Shanghai Connect”) or the Shenzhen-Hong Kong Stock Connect program (“Shenzhen Connect” and, together with Shanghai Connect, “Stock Connect”) or the Qualified Foreign Institutional Investor (“QFII”) system. The Fund may invest in issuers of any market capitalization. The Fund primarily seeks to buy common stock and may also invest in preferred stock. From time to time, the Fund may invest in shares of companies through “new issues” or initial public offerings (“IPOs”). The Fund may also purchase convertible securities.

The Fund intends to invest in A-shares primarily through Stock Connect. Trading through Stock Connect is subject to a daily quota (the “Daily Quota”), which limits the maximum net purchases under Stock Connect each day and, as such, buy orders for A-shares would be rejected once the Daily Quota is exceeded (although the Fund will be permitted to sell A-shares regardless of the Daily Quota balance).

The Fund may use derivatives, including options, futures, swaps (including, but not limited to, total return swaps, some of which may be referred to as contracts for difference) and forward contracts, both to seek to increase the return of the Fund and to hedge (or protect) the value of its assets against adverse movements in currency exchange rates, interest rates and movements in the securities markets. In order to manage cash flows into or out of the Fund effectively, the Fund may buy and sell financial futures contracts or options on such contracts. Derivatives are financial instruments whose value is derived from another security, a commodity, a currency or an index, including but not limited to the MSCI China A Onshore Index. The use of options, futures, swaps and forward contracts can be effective in protecting or enhancing the value of the Fund’s assets. The Fund may engage in active and frequent trading of portfolio securities to seek to achieve its primary investment strategies.

Risk [Heading]

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Principal Risks of Investing in the Fund

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Performance Information

Performance Narrative [Text Block]

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The information shows you how the performance of the Fund has varied for the periods since inception and provides some indication of the risks of investing in the Fund. The table compares the Fund’s performance to that of the MSCI China A Onshore Index. To the extent that dividends and distributions have been paid by the Fund, the performance information for the Fund in the chart and table assumes reinvestment of the dividends and distributions. As with all such investments, past performance (before and after taxes) is not an indication of future results. The table includes all applicable fees. If BlackRock and its affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund’s returns would have been lower. Updated information on the Fund’s performance, including its current net asset value, can be obtained by visiting www.blackrock.com or can be obtained by phone at (800) 882-0052.

Performance Information Illustrates Variability of Returns [Text]

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The information shows you how the performance of the Fund has varied for the periods since inception and provides some indication of the risks of investing in the Fund.

Performance Availability Phone [Text]

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(800) 882-0052

Performance Availability Website Address [Text]

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www.blackrock.com

Performance Past Does Not Indicate Future [Text]

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As with all such investments, past performance (before and after taxes) is not an indication of future results.

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Class K Shares ANNUAL TOTAL RETURNS BlackRock China A Opportunities Fund As of 12/31

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During the periods shown in the bar chart, the highest return for a quarter was 31.91% (quarter ended March 31, 2019) and the lowest return for a quarter was -20.16% (quarter ended September 30, 2022).

Performance Table Heading

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For the periods ended 12/31/24Average Annual Total Returns

Performance Table Uses Highest Federal Rate

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After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes.

Performance Table Not Relevant to Tax Deferred

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Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Performance Table Narrative

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After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor’s tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.

Class K | BlackRock China A Opportunities Fund | Risk Lose Money [Member]

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Class K | BlackRock China A Opportunities Fund | China Investments Risk [Member]

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

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Class K | BlackRock China A Opportunities Fund | China Risk Risk of Investing through Stock Connect [Member]

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China Investments Risk — Investments in Chinese securities, including certain Hong Kong-listed and U.S.-listed securities, subject the Fund to risks specific to China. China may be subject to considerable degrees of economic, political and social instability. China is an emerging market and demonstrates significantly higher volatility from time to time in comparison to developed markets. Over the last few decades, the Chinese government has undertaken reform of economic and market practices and has expanded the sphere of private ownership of property in China. However, Chinese markets generally continue to experience inefficiency, volatility and pricing anomalies resulting from governmental influence, a lack of publicly available information and/or economic, political and social instability. The A-shares market has a higher propensity for trading suspensions than many other global equity markets. Trading suspensions in certain stocks could lead to greater market execution risk and costs for the Fund. Chinese companies are also subject to the risk that Chinese authorities can intervene in their operations and structure. Internal social unrest or confrontations with other neighboring countries, including military conflicts in response to

such events, may also disrupt economic development in China and result in a greater risk of currency fluctuations, currency non-convertibility, interest rate fluctuations and higher rates of inflation.

China has experienced security concerns, such as terrorism and strained international relations. Additionally, China is alleged to have participated in state-sponsored cyberattacks against foreign companies and foreign governments. Actual and threatened responses to such activity and strained international relations, including purchasing restrictions, sanctions, tariffs or cyberattacks on the Chinese government or Chinese companies, may impact China’s economy and Chinese issuers of securities in which the Fund invests. Incidents involving China’s or the region’s security may cause uncertainty in the Chinese markets and may adversely affect the Chinese economy and the Fund’s investments. Export growth continues to be a major driver of China’s rapid economic growth. Reduction in spending on Chinese products and services, supply chain diversification, institution of tariffs, sanctions or other trade barriers (including as a result of heightened trade tensions or a trade war between China and the U.S., or in response to actual or alleged Chinese cyber activity) or a downturn in any of the economies of China’s key trading partners may have an adverse impact on the Chinese economy. Certain companies may be subject to commercial or trade restrictions (but not investment restrictions) imposed by the U.S. or other governments due to national security, human rights or other concerns of such government. So long as these restrictions do not include restrictions on investments, the Fund may invest in such companies.

The United States and China have been engaged in an ongoing trade war with one another, which has led to trade frictions between their economies and negative flow-on consequences on global markets and other nations closely affiliated with those countries. The current political climate has intensified concerns about the ongoing trade war between China and the United States, as each country has imposed tariffs on the other country’s products. These actions may trigger a significant reduction in international trade, the oversupply of certain manufactured goods, substantial price reductions of goods and possible failure of individual companies and/or large segments of China’s export industry, which could have a negative impact on the Fund’s performance. In addition, there is a risk that further capital controls and/or sanctions may be imposed, which could include the prohibition of, or restrictions on, the ability to own or transfer currency, securities, derivatives or other assets and may also include retaliatory actions, such as seizure of assets. Any of these actions could severely impair the Fund’s ability to purchase, sell, transfer, receive, deliver or otherwise obtain exposure to Chinese securities and assets, including the ability to transfer the Fund’s assets or income back into the United States, and could negatively impact the value and/or liquidity of such assets or otherwise adversely affect the Fund’s operations, causing the Fund to decline in value. Events such as these and their consequences are difficult to predict and it is unclear whether further tariffs may be imposed or other escalating actions may be taken in the future. From time to time, China has experienced outbreaks of infectious illnesses, including the novel coronavirus known as “COVID-19.” The country may be subject to other public health threats, infectious illnesses, diseases or similar issues in the future. Any spread of an infectious illness, public health threat or similar issue could reduce consumer demand or economic output, result in market closures, travel restrictions or quarantines, and generally have a significant impact on the Chinese economy, which in turn could adversely affect the Fund’s investments.

Chinese companies, including Chinese companies that are listed on U.S. exchanges, may not be subject to the same degree of regulatory requirements, accounting standards or auditor oversight as companies in more developed countries. As a result, information about the Chinese securities in which the Fund invests may be less reliable or complete. Chinese companies with securities listed on U.S. exchanges may be delisted if they do not meet U.S. accounting standards and auditor oversight requirements, which would significantly decrease the liquidity and value of the securities. There may be significant obstacles to obtaining information necessary for investigations into or litigation against Chinese companies, and investors in such companies, including the Fund, may have limited legal remedies.

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Class K | BlackRock China A Opportunities Fund | Equity Securities Risk [Member]

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China Risk — Risk of Investing through Stock Connect — Investing in eligible ETFs and A-shares (“Stock Connect Securities”) through Stock Connect is subject to trading, clearance, settlement and other procedures, which could pose risks to the Fund. Trading through Stock Connect is subject to the Daily Quota, which may restrict the Fund’s ability to invest in Stock Connect Securities through Stock Connect on a timely basis and could affect the Fund’s ability to effectively pursue its investment strategy. Stock Connect will only operate on days when both the Chinese and Hong Kong markets are open for trading and when banking services are available in both markets on the corresponding settlement days. Therefore, an investment in Stock Connect Securities through Stock Connect may subject the Fund to the risk of price fluctuations on days when the Chinese markets are open, but Stock Connect is not trading.

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Class K | BlackRock China A Opportunities Fund | Geographic Concentration Risks [Member]

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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.

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Class K | BlackRock China A Opportunities Fund | China Tax Risk [Member]

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Geographic Concentration Risk — The Fund will invest primarily in securities of companies domiciled, or exercising the predominant part of their economic activity, in China. Because the Fund concentrates its investments in this

manner, it assumes the risk that economic, political and social conditions in China will have a significant impact on the Fund’s investment performance which may be more volatile than the performance of more geographically diversified funds. In addition, a natural or manmade disaster could occur in China. China is located in a part of the world that has historically been prone to natural disasters such as floods, droughts, earthquakes, typhoons or tsunamis, and is economically sensitive to environmental events. Any such event may adversely impact China’s economy and the value of the securities in the Fund.

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Class K | BlackRock China A Opportunities Fund | Convertible Securities Risk [Member]

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China Tax Risk — Withholding Income Tax Risk – According to PRC tax regulations, a 10% withholding income tax is imposed on PRC sourced dividends and interests from non-government bonds paid to a non-PRC tax resident enterprise, unless the rate is reduced under an applicable tax treaty. From a technical perspective, withholding income tax is also applicable to capital gains realized by foreign investors on the disposal of PRC equity interests.

There are however certain tax exemptions available, some temporary in nature, highlighted below.

On November 14, 2014, the Ministry of Finance (“MoF”), China Securities Regulatory Commission and the State Taxation Administration (“STA”), acting with State Council’s approval, jointly released Circular 79, which temporarily exempts Qualified Foreign Institutional Investors (“QFIIs”) and Renminbi Qualified Foreign Institutional Investors (“RQFIIs”) from tax on capital gains derived from the trading of shares and other equity interest investments on or after November 17, 2014. Subsequently, Circulars 81 and 127 were issued to temporarily exempt tax on capital gains derived from trading of equity securities of companies domiciled in the PRC that trade on Chinese stock exchanges (“A-Shares”) through the Shanghai-Hong Kong Stock Connect program or the Shenzhen-Hong Kong Stock Connect program, as applicable (each, a “Stock Connect” and collectively, “Stock Connects”). The duration of the temporary exemptions is not stated in the circulars and is subject to termination by the PRC tax authorities with or without notice.

On November 22, 2018, the MoF and STA jointly issued Circular 108 which states that foreign institutional investors are temporarily exempt from withholding income tax with respect to interest income on bonds derived from the PRC bond market from November 7, 2018 to November 6, 2021. On November 22, 2021, the MoF and STA issued Public Notice 34 to extend the temporary exemption from November 7, 2021 to December 31, 2025.

Value Added Tax (“VAT”) Risk – From May 1, 2016, VAT applies to certain income derived by the Fund, including PRC sourced interest income on non-government bonds and trading gains.

There are however certain tax exemptions available, some temporary in nature, highlighted below.

VAT exemptions currently apply to capital gains from trading of QFII and RQFII products, A-Shares traded on the Stock Connects and debt securities traded in the China Interbank Bond Market.

On November 7, 2018, the MoF and STA jointly issued Circular 108 which states that foreign institutional investors are temporarily exempt from VAT with respect to interest income on bonds derived from the PRC bond market from November 7, 2018 to November 6, 2021. On November 22, 2021, the MoF and STA issued Public Notice 34 to extend the temporary exemption from November 7, 2021 to December 31, 2025.

Any changes in PRC tax law, future clarifications thereof, and/or subsequent retroactive enforcement by the PRC tax authorities may result in a loss which could be material to the Fund. There is a risk the PRC tax authorities may withdraw the temporary tax exemptions in the future and seek to collect taxes realized on the sale of A-Shares or PCR sourced interest income on non-government bonds received by the Fund without giving any prior notice. If the tax exemptions are withdrawn, any taxes may be directly borne by or indirectly passed on to the Fund and may result in a substantial impact to its net asset value. As with any net asset value adjustment, investors may be advantaged or disadvantaged depending on when the investors purchased and/or sold the shares of the Fund. There will be no retrospective restatement of the Fund’s net asset value.

BlackRock will keep the provisioning policy for tax liability under review and may, in its discretion from time to time, make a provision for potential tax liabilities if in its opinion such provision is warranted or as further clarified by the PRC in notifications.

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Class K | BlackRock China A Opportunities Fund | Currency Risk [Member]

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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.

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Class K | BlackRock China A Opportunities Fund | Derivatives Risks [Member]

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Currency Risk — The Fund’s assets will be invested primarily in domestic Chinese equities and the income received by the Fund will be primarily in RMB. Because the Fund’s net asset value is determined on the basis of the U.S. dollar, investors may lose money if the RMB depreciates against the U.S. dollar, even if the local currency values of

the Fund’s holdings in Chinese securities increase. Furthermore, the Fund may incur costs in connection with conversions between U.S. dollars and RMB, as well as in connection with conversions between the two separate types of RMB, the onshore RMB (“CNY”) and the offshore RMB (“CNH”).

In addition, there is no assurance that there will always be sufficient amounts of RMB available for the Fund to remain fully invested in Chinese equities. The Chinese government heavily regulates the domestic exchange of foreign currencies and RMB exchange rates in China, which may adversely affect the operations and financial results of the Fund’s investments in China.

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Class K | BlackRock China A Opportunities Fund | Emerging Markets Risk [Member]

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Derivatives Risk — The Fund’s use of derivatives may increase its costs, reduce the Fund’s returns and/or increase volatility. Derivatives involve significant risks, including:

Leverage Risk — The Fund’s use of derivatives can magnify the Fund’s gains and losses. Relatively small market movements may result in large changes in the value of a derivatives position and can result in losses that greatly exceed the amount originally invested.

Market Risk — Some derivatives are more sensitive to interest rate changes and market price fluctuations than other securities. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, which losses are potentially unlimited. Finally, BlackRock may not be able to predict correctly the direction of securities prices, interest rates and other economic factors, which could cause the Fund’s derivatives positions to lose value.

Counterparty Risk — Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will be unable or unwilling to fulfill its contractual obligation, and the related risks of having concentrated exposure to such a counterparty.

Illiquidity Risk — The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately.

Operational Risk — The use of derivatives includes the risk of potential operational issues, including documentation issues, settlement issues, systems failures, inadequate controls and human error.

Legal Risk — The risk of insufficient documentation, insufficient capacity or authority of counterparty, or legality or enforceability of a contract.

Volatility and Correlation Risk — Volatility is defined as the characteristic of a security, an index or a market to fluctuate significantly in price within a short time period. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate with the overall securities markets.

Valuation Risk — Valuation for derivatives may not be readily available in the market. Valuation may be more difficult in times of market turmoil since many investors and market makers may be reluctant to purchase complex instruments or quote prices for them.

Hedging Risk — Hedges are sometimes subject to imperfect matching between the derivative and the underlying security, and there can be no assurance that the Fund’s hedging transactions will be effective. The use of hedging may result in certain adverse tax consequences.

Tax Risk — Certain aspects of the tax treatment of derivative instruments, including swap agreements and commodity-linked derivative instruments, are currently unclear and may be affected by changes in legislation, regulations or other legally binding authority. Such treatment may be less favorable than that given to a direct investment in an underlying asset and may adversely affect the timing, character and amount of income the Fund realizes from its investments.

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Class K | BlackRock China A Opportunities Fund | High Portfolio Turnover Risk [Member]

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Emerging Markets Risk — Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyperinflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging securities markets have far lower trading volumes and less liquidity than developed markets.

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Class K | BlackRock China A Opportunities Fund | Information Technology Sector Risk [Member]

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High Portfolio Turnover Risk — The Fund may engage in active and frequent trading of its portfolio securities. High portfolio turnover (more than 100%) may result in increased transaction costs to the Fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of the securities and on reinvestment in other securities. The sale of Fund portfolio securities may result in the realization and/or distribution to shareholders of higher capital gains or losses as compared to a fund with less active trading policies. These effects of higher than normal portfolio turnover may adversely affect Fund performance.

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Class K | BlackRock China A Opportunities Fund | Investment in a Particular Geographic Region or Country Risk Asia Pacific Countries [Member]

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Information Technology Sector Risk — Information technology 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 information technology sector are facing 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.

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Class K | BlackRock China A Opportunities Fund | Leverage Risk [Member]

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Investment in a Particular Geographic Region or Country Risk — Asia-Pacific Countries — In addition to the risks of investing in non-U.S. securities and the risks of investing in emerging markets, Asia-Pacific countries are subject to certain additional or specific risks.

In many of the emerging market Asia-Pacific countries, there is a high concentration of market capitalization and trading volume in a small number of issuers representing a limited number of industries, as well as a high concentration of investors and financial intermediaries. Many emerging market Asia-Pacific countries have experienced rapid growth and industrialization in recent years, but there is no assurance that this growth rate will be maintained. Other emerging market Asia-Pacific countries, however, have experienced high inflation, high unemployment, currency devaluations and restrictions, and over-extension of credit. Brokers in emerging market Asia-Pacific countries typically are fewer in number and less well capitalized than brokers in the United States.

Many of the emerging market Asia-Pacific countries may be subject to a greater degree of economic, political and social instability than is the case in the United States and Western European countries. Such instability may result from, among other things: (i) authoritarian governments or military involvement in political and economic decision-making, including changes in government through extra-constitutional means; (ii) popular unrest associated with demands for improved political, economic and social conditions; (iii) internal insurgencies; (iv) hostile relations with neighboring countries; and (v) ethnic, religious and racial disaffection. In addition, the governments of many of such countries have a substantial role in regulating and supervising the economy.

Another risk common to most such countries is that the economy is heavily export oriented and, accordingly, is dependent upon international trade. The existence of overburdened infrastructure and obsolete financial systems also presents risks in certain countries, as do environmental problems. Certain economies also depend to a significant degree upon exports of primary commodities and, therefore, are vulnerable to changes in commodity prices that, in turn, may be affected by a variety of factors.

The rights of investors in emerging market Asia-Pacific companies may be more limited than those of shareholders of U.S. corporations. It may be difficult or impossible to obtain and/or enforce a judgment in a emerging market Asia-Pacific country.

Some developing Asia-Pacific countries prohibit or impose substantial restrictions on investments in their capital markets, particularly their equity markets, by foreign entities. For example, certain countries may require governmental approval prior to investments by foreign persons or limit the amount of investment by foreign persons in a particular company.

Geopolitical hostility, political instability, and economic or environmental events in any one of the Asia-Pacific countries may have a significant economic effect on the entire Asia-Pacific region, as well as on major trading partners outside the Asia-Pacific region. Any adverse event in the Asia-Pacific markets may have a significant adverse effect on some or all of the economies of the Asia-Pacific countries. In particular, China is a key trading partner of many Asia-Pacific countries and any changes in trading relationships between China and other Asia-Pacific countries may affect the region as a whole. Many Asia-Pacific countries are subject to political risk, including political instability, corruption and regional conflict with neighboring countries. North Korea and South Korea each have substantial military capabilities, and historical tensions between the two countries present the risk of war. Escalated tensions involving the two countries and any outbreak of hostilities between the two countries, or even the threat of an outbreak of hostilities, could have a severe adverse effect on the entire Asia-Pacific region. Certain Asia-Pacific countries have developed increasingly strained relationships with the U.S., and if these relations were to worsen, they could adversely affect Asia-Pacific issuers that rely on the U.S. for trade. In addition, many Asia-Pacific countries are subject to social and labor risks associated with demands for improved political, economic and social conditions.

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Class K | BlackRock China A Opportunities Fund | Market Risk and Selection Risk [Member]

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Leverage Risk — Some transactions may give rise to a form of economic leverage. These transactions may include, among others, derivatives, and may expose the Fund to greater risk and increase its costs. The use of leverage may cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or to meet the applicable requirements of the Investment Company Act of 1940, as amended, and the rules thereunder. Increases and decreases in the value of the Fund’s portfolio will be magnified when the Fund uses leverage.

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Class K | BlackRock China A Opportunities Fund | Model Risk [Member]

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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. The Fund seeks to pursue its investment objective by using proprietary models that incorporate quantitative analysis and is subject to “Model Risk” as described below. This means you may lose money.

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Class K | BlackRock China A Opportunities Fund | New Issues Risk [Member]

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Model Risk — The Fund seeks to pursue its investment objective by using proprietary models that incorporate quantitative analysis. Investments selected using these models may perform differently than as forecasted due to the factors incorporated into the models and the weighting of each factor, changes from historical trends, and issues in the construction and implementation of the models (including, but not limited to, software issues and other technological issues). There is no guarantee that BlackRock’s use of these models will result in effective investment decisions for the Fund.

The information and data used in the models may be supplied by third parties. Inaccurate or incomplete data may limit the effectiveness of the models. In addition, some of the data that BlackRock uses may be historical data, which may not accurately predict future market movement. There is a risk that the models will not be successful in selecting investments or in determining the weighting of investment positions that will enable the Fund to achieve its investment objective.

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Class K | BlackRock China A Opportunities Fund | Preferred Securities Risk [Member]

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“New Issues” Risk — “New issues” are IPOs of equity securities. Securities issued in IPOs have no trading history, and information about the companies may be available for very limited periods. In addition, the prices of securities sold in IPOs may be highly volatile or may decline shortly after the IPO.

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Class K | BlackRock China A Opportunities Fund | Small Cap and Emerging Growth Securities Risk [Member]

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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.

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Class K | BlackRock China A Opportunities Fund | Class K Shares

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Small Cap and Emerging Growth Securities Risk — Small cap or emerging growth companies may have limited product lines or markets. They may be less ﬁnancially secure than larger, more established companies. They may depend on a more limited management group than larger capitalized companies.

Distribution and/or Service (12b-1) Fees

rr_RiskReturnAbstract

Management Fee

rr_ManagementFeesOverAssets

0.75%

^[1]

rr_DistributionAndService12b1FeesOverAssets

none

Miscellaneous Other Expenses

rr_Component1OtherExpensesOverAssets

2.26%

Interest Expense

rr_Component2OtherExpensesOverAssets

0.01%

Other Expenses

rr_OtherExpensesOverAssets

2.27%

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

3.02%

Fee Waivers and/or Expense Reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(2.07%)

^[1],[2]

Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements

rr_NetExpensesOverAssets

0.95%

^[1],[2]

rr_ExpenseExampleYear01

$ 97

3 Years

rr_ExpenseExampleYear03

738

Highest Quarterly Return, Label

rr_ExpenseExampleYear05

1,404

10 Years

rr_ExpenseExampleYear10

$ 3,190

2019

rr_AnnualReturn2019

44.39%

2020

rr_AnnualReturn2020

48.61%

2021

rr_AnnualReturn2021

3.68%

2022

rr_AnnualReturn2022

(28.49%)

2023

rr_AnnualReturn2023

(12.28%)

2024

rr_AnnualReturn2024

15.48%

rr_HighestQuarterlyReturnLabel

highest return

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Mar. 31, 2019

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

31.91%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

lowest return

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2022

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(20.16%)

rr_AverageAnnualReturnYear01

15.48%

rr_AverageAnnualReturnYear05

2.22%

Class K | BlackRock China A Opportunities Fund | Return After Taxes on Distributions | Class K Shares

rr_AverageAnnualReturnSinceInception

8.43%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 27, 2018

rr_RiskReturnAbstract

rr_AverageAnnualReturnYear01

15.15%

rr_AverageAnnualReturnYear05

1.84%

Class K | BlackRock China A Opportunities Fund | Return After Taxes on Distributions and Sale of Fund Shares | Class K Shares

rr_AverageAnnualReturnSinceInception

7.30%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 27, 2018

rr_RiskReturnAbstract

rr_AverageAnnualReturnYear01

9.83%

rr_AverageAnnualReturnYear05

1.86%

Class K | BlackRock China A Opportunities Fund | MSCI China A Onshore Index (Reflects no deduction for fees, expenses or taxes)

rr_AverageAnnualReturnSinceInception

6.49%

Inception Date

rr_AverageAnnualReturnInceptionDate

Dec. 27, 2018

rr_RiskReturnAbstract

rr_AverageAnnualReturnYear01

11.59%

rr_AverageAnnualReturnYear05

0.89%