Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Jan. 25, 2018
BlackRock Commodity Strategies Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview Key Facts About BlackRock Commodity Strategies Fund
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Commodity Strategies Fund (the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek total return.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold Class K Shares of the Fund.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	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	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	November 30, 2019
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover:
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 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 96% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	96.00%
Other Expenses, New Fund, Based on Estimates [Text]	rr_OtherExpensesNewFundBasedOnEstimates	Other Expenses are based on estimated amounts for the current year.
Expense Example [Heading]	rr_ExpenseExampleHeading	Example:
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in 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]	rr_StrategyHeading	Principal Investment Strategies of the Fund
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund utilizes two strategies and under normal circumstances expects to invest approximately 50% of its total assets in each strategy; provided, however, that from time to time, Fund management may alter the weightings if it deems it prudent to do so based on market conditions, trends or movements or other similar factors. One strategy focuses on investments in commodity-linked derivatives. To meet coverage and collateral requirements associated with these derivative investments, and to invest excess cash, the Fund holds a portion of its portfolio in investment-grade short-term fixed-income securities. The other strategy focuses on equity investments in commodity-related companies, including, but not limited to, companies operating in the mining, energy and agricultural sectors. The Fund invests in equity securities of such companies in order to complement the commodity exposures achieved through investments in commodity-linked derivatives. Taken together, these two strategies offer broad exposure to global commodities market trends across asset classes, industries, sectors, and regions. Commodities are assets that have tangible properties, such as oil and other energy products, metals, and agricultural products. Commodity-linked derivative instruments include, but are not limited to, commodity-linked notes, swap agreements, commodity options, futures and options on futures, that provide exposure to the investment returns of the commodities markets, without investing directly in physical commodities. Commodity-related companies include, but are not limited to, companies in commodities, natural resources and energy businesses and in associated businesses and companies that provide services or have exposure to such businesses (collectively, the “Commodities Sector”). These companies include, without limitation, companies engaged in the exploration, ownership, production, refinement, processing, transportation, distribution or marketing of commodities, companies that use commodities extensively in their products and companies that provide technology and services to commodity-related companies. This includes companies that are engaged in businesses such as integrated oil, oil and gas exploration and production, energy services and technology, chemicals and oil products, coal and other consumable fuel, gold and precious metals, metals and minerals, forest products, agricultural chemicals and services, farm land, alternative energy sources, environmental services and agricultural products (including crop growers, owners of plantations, and companies that produce and process foods), as well as related transportation companies, equipment manufacturers, service providers and engineering, procurement and construction (“EPC”) companies. The Fund may make investments directly or through investments in BlackRock Cayman Commodity Strategies Fund, Ltd. (the “Subsidiary”), a wholly-owned subsidiary of the Fund formed in the Cayman Islands. The Subsidiary is managed by BlackRock and has the same investment objective as the Fund. The assets of the Subsidiary are subject to the same investment restrictions and limitations, and follow the same compliance policies and procedures, as the Fund, except that the Subsidiary does not invest in equity securities of commodity-related companies, and may invest without limitation in commodity-linked derivative instruments. The Fund will not invest more than 25% of its total assets (measured at the time of investment) in the Subsidiary. The Fund manages the term structure of its commodity-linked derivative positions and has the flexibility to gain exposure to futures maturities which differ from those in the Fund’s benchmark, the Bloomberg Commodity Index Total ReturnSM. This is done in an effort to achieve efficient investment results and minimize any adverse effects on returns caused by commodity term structures. Equity securities held by the Fund may include common stocks, preferred stocks, convertible securities, warrants, depositary receipts, and other instruments whose price is linked to the value of common stock, and equity interests in master limited partnerships. In addition, the Fund may also invest in fixed-income instruments (of any credit quality and any duration) of commodity-related companies. There are no restrictions on investment in terms of geography or market capitalization. As such, the Fund may invest in both U.S. and non-U.S. companies, including companies located in emerging markets, and in securities denominated in both U.S. dollars and foreign currencies.
Risk [Heading]	rr_RiskHeading	Principal Risks of Investing in the Fund
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	Risk is inherent in all investing. The value of your investment in the Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. The following is a summary description of principal risks of investing in the Fund. Commodities Investment Risk — Investing in commodity-linked derivative instruments and equity securities of commodity-related companies may subject the Fund to greater volatility than investments in traditional securities. The commodities markets have experienced periods of extreme volatility. Similar future market conditions may result in rapid and substantial valuation increases or decreases in the Fund’s holdings. The commodities markets may fluctuate widely based on a variety of factors. Movements in commodity investment prices are outside of the Fund’s control and may not be anticipated by Fund management. Price movements may be influenced by, among other things: governmental, agricultural, trade, fiscal, monetary and exchange control programs and policies; changing market and economic conditions; market liquidity; weather and climate conditions; changing supply and demand relationships and levels of domestic production and imported commodities; the availability of local, intrastate and interstate transportation systems; energy conservation; the success of exploration projects; changes in international balances of payments and trade; domestic and foreign rates of inflation; currency devaluations and revaluations; domestic and foreign political and economic events; domestic and foreign interest rates and/or investor expectations concerning interest rates; foreign currency/exchange rates; domestic and foreign governmental regulation and taxation; war, acts of terrorism and other political upheaval and conflicts; governmental expropriation; investment and trading activities of mutual funds, hedge funds and commodities funds; changes in philosophies and emotions of market participants. The frequency and magnitude of such changes cannot be predicted. The commodity markets are subject to temporary distortions and other disruptions due to, among other factors, lack of liquidity, the participation of speculators, and government regulation and other actions. U.S. futures exchanges and some foreign exchanges limit the amount of fluctuation in futures contract prices which may occur in a single business day (generally referred to as “daily price fluctuation limits”). The maximum or minimum price of a contract as a result of these limits is referred to as a “limit price.” If the limit price has been reached in a particular contract, no trades may be made beyond the limit price. Limit prices have the effect of precluding trading in a particular contract or forcing the liquidation of contracts at disadvantageous times or prices. Commodities Regulatory Risk — Commodity-related companies are subject to significant federal, state and local government regulation in virtually every aspect of their operations, including how facilities are constructed, maintained and operated, environmental and safety controls, and the prices they may charge for the products and services they provide. The U.S. Commodity Futures Trading Commission (the “CFTC”) and the U.S. commodities exchanges are authorized to take extraordinary actions in the event of a market emergency, including, for example, the imposition of higher margin requirements, the establishment of daily limits and the suspension of trading. Any of these actions, if taken, could adversely affect the returns of the Fund by limiting or precluding investment decisions the Fund might otherwise make. The CFTC and the U.S. commodities exchanges impose limits referred to as “speculative position limits” on the maximum net long or net short speculative positions that any person may hold or control in any particular futures, options contracts or swaps traded on U.S. commodities exchanges. The CFTC has proposed a new set of speculative position limit rules which are not yet finalized (or effective). If the CFTC successfully implements these position limits, the size or duration of positions available to the Fund may be severely limited. Pursuant to the Dodd-Frank Wall Street Reform and Consumer Protection Act (“Dodd-Frank Act”), swaps and other financial derivative products are subject to increased regulatory oversight and may in the future become subject to further increased regulatory oversight. BlackRock cannot predict the effects of any new governmental regulation that may be implemented on the ability of the Fund to use swaps or any other financial derivative product, and there can be no assurance that any new governmental regulation will not adversely affect the Fund’s ability to achieve its investment objectives. In addition, the Internal Revenue Service (the “IRS”) (i) will no longer issue private letter rulings on the tax treatment of a mutual fund investment in commodity-linked derivatives if the ruling would depend on whether the investment is a security under the 1940 Act and (ii) issued proposed regulations that, if finalized in current form, would specify that a subpart F income inclusion for U.S. federal income tax purposes would be treated as qualifying income only to the extent that the Subsidiary makes distributions out of its earnings and profits in the same taxable year. See “— Subsidiary Risk” below. Credit Risk — Credit risk refers to the possibility that the issuer of a security will not be able to make payments of interest and principal when due. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also affect the value of the Fund’s investment in that issuer. 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: Volatility 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. Counterparty Risk — Derivatives are also subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Market and Liquidity 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. Valuation Risk — 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. Regulatory Risk — Derivative contracts, including, without limitation, swaps, currency forwards and non-deliverable forwards, are subject to regulation under the Dodd-Frank Act in the United States and under comparable regimes in Europe, Asia and other non-U.S. jurisdictions. Under the Dodd-Frank Act, certain derivatives are subject to margin requirements and swap dealers are required to collect margin from the Fund with respect to such derivatives. Specifically, regulations are now in effect that require swap dealers to post and collect variation margin (comprised of specified liquid instruments and subject to a required haircut) in connection with trading of over-the-counter (“OTC”) swaps with the Fund. Shares of investment companies (other than certain money market funds) may not be posted as collateral under these regulations. Requirements for posting of initial margin in connection with OTC swaps will be phased-in through 2020. In addition, regulations adopted by prudential regulators that will begin to take effect in 2019 will require certain bank-regulated counterparties and certain of their affiliates to include in certain financial contracts, including many derivatives contracts, terms that delay or restrict the rights of counterparties, such as the Fund, to terminate such contracts, foreclose upon collateral, exercise other default rights or restrict transfers of credit support in the event that the counterparty and/or its affiliates are subject to certain types of resolution or insolvency proceedings. The implementation of these requirements with respect to derivatives, as well as regulations under the Dodd-Frank Act regarding clearing, mandatory trading and margining of other derivatives may increase the costs and risks to the Fund of trading in these instruments and, as a result, may affect returns to investors in the Fund. Risks Specific to Certain Derivatives Used by the Fund Commodity-Linked Derivatives – The value of a commodity-linked derivative investment typically is based upon the price movements of a commodity, a commodity futures contract or commodity index, or some other readily measurable economic variable. The value of commodity-linked derivative instruments may be affected by changes in overall market movements, volatility of the underlying benchmark, changes in interest rates, or factors affecting a particular industry or commodity, such as drought, floods, weather, livestock disease, embargoes, tariffs and international economic, political and regulatory developments. The value of commodity-linked derivatives will rise or fall in response to changes in the underlying commodity or related index. Investments in commodity-linked derivatives may be subject to greater volatility than non-derivative based investments. A highly liquid secondary market may not exist for certain commodity-linked derivatives, and there can be no assurance that one will develop. Commodity-linked derivatives also may be subject to credit and interest rate risks that in general affect the values of fixed-income securities. Therefore, at maturity, the Fund may receive more or less principal than it originally invested. The Fund might receive interest payments that are more or less than the stated coupon interest payments. In connection with the Fund’s direct and indirect investments in commodity-linked derivatives, the Fund will attempt to manage its counterparty exposure so as to limit its exposure to any one counterparty. However, due to the limited number of entities that may serve as counterparties (and which the Fund believes are creditworthy) at any one time the Fund may enter into swap agreements with a limited number of counterparties and may invest in commodity-linked notes issued by a limited number of issuers that will act as counterparties, which may increase the Fund’s exposure to counterparty credit risk. There can be no assurance that the Fund will be able to limit exposure to any one counterparty at all times. Commodity-Linked Notes – Commodity-linked notes involve substantial risks, including the risk of loss of a significant portion of their principal value. In addition to commodity risk and general derivatives risk, they may be subject to additional special risks, such as risk of loss of interest and principal, lack of secondary market and risk of greater volatility, that do not affect traditional equity and debt securities. Futures – Futures are standardized, exchange-traded contracts that obligate a purchaser to take delivery, and a seller to make delivery, of a specific amount of an asset at a specified future date at a specified price. The primary risks associated with the use of futures contracts and options are: (a) the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract or option; (b) the possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; (c) losses caused by unanticipated market movements, which are potentially unlimited; (d) the investment adviser’s inability to predict correctly the direction of securities prices, interest rates, currency exchange rates and other economic factors; and (e) the possibility that the counterparty will default in the performance of its obligations. Swaps – Swap agreements are two-party contracts entered into for periods ranging from a few weeks to more than one year. In a standard “swap” transaction, two parties agree to exchange the returns (or differentials in rates of return) earned or realized on particular predetermined investments or instruments, which can be adjusted for an interest factor. Swap agreements involve the risk that the party with whom the Fund has entered into the swap will default on its obligation to pay the Fund and the risk that the Fund will not be able to meet its obligations to pay the other party to the agreement. Forward Foreign Currency Exchange Contracts – Forward foreign currency exchange transactions are OTC contracts to purchase or sell a specified amount of a specified currency or multinational currency unit at a price and future date set at the time of the contract. Forward foreign currency exchange contracts do not eliminate fluctuations in the value of non-U.S. securities but rather allow the Fund to establish a fixed rate of exchange for a future point in time. This strategy can have the effect of reducing returns and minimizing opportunities for gain. 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. 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. Foreign Securities Risk — Foreign investments often involve special risks not present in U.S. investments that can increase the chances that the Fund will lose money. These risks include: The Fund generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight. Changes in foreign currency exchange rates can affect the value of the Fund’s portfolio. The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position. The governments of certain countries may prohibit or impose substantial restrictions on foreign investments in their capital markets or in certain industries. Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws. Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments. Interest Rate Risk — Interest rate risk is the risk that prices of bonds and other fixed-income securities will increase as interest rates fall, and decrease as interest rates rise. 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 any required asset segregation requirements. Increases and decreases in the value of the Fund’s portfolio will be magnified when the Fund uses leverage. 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. 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. 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. Precious Metal and Related Securities Risk — Prices of precious metals and of precious metal related securities historically have been very volatile. The high volatility of precious metal prices may adversely affect the financial condition of companies involved with precious metals. The production and sale of precious metals by governments or central banks or other larger holders can be affected by various economic, financial, social and political factors, which may be unpredictable and may have a significant impact on the prices of precious metals. Other factors that may affect the prices of precious metals and securities related to them include changes in inflation, the outlook for inflation and changes in industrial and commercial demand for precious metals. Sector Risk — Sector risk is the risk that the Fund’s concentration in the securities of companies in a specific market sector or industry will cause the Fund to be more exposed to the price movements of companies in and developments affecting that sector than a more broadly diversified fund. The Fund’s investments will be concentrated in a group of industries that make up the Commodities Sector. Because the Fund is focused in specific industries, it may present more risks than if it were broadly diversified over numerous industries and sectors of the economy. 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. Subsidiary Risk — By investing in the Subsidiary, the Fund is indirectly exposed to the risks associated with the Subsidiary’s investments. The commodity-related instruments held by the Subsidiary are generally similar to those that are permitted to be held by the Fund and are subject to the same risks that apply to similar investments if held directly by the Fund. There can be no assurance that the investment objective of the Subsidiary will be achieved. The Subsidiary is not registered under the Investment Company Act of 1940, as amended (the “Investment Company Act”), and, unless otherwise noted in this prospectus, is not subject to all the investor protections of the Investment Company Act. However, the Fund wholly owns and controls the Subsidiary, and the Fund and the Subsidiary are both managed by BlackRock, making it unlikely that the Subsidiary will take action contrary to the interests of the Fund and its shareholders. The Board has oversight responsibility for the investment activities of the Fund, including its investment in the Subsidiary, and the Fund’s role as sole shareholder of the Subsidiary. The Subsidiary is subject to the same investment restrictions and limitations, and follows the same compliance policies and procedures, as the Fund. Changes in the laws of the United States and/or the Cayman Islands could result in the inability of the Fund and/or the Subsidiary to operate as described in this prospectus and the SAI and could adversely affect the Fund. In order to qualify as a regulated investment company, at least 90% of the Fund’s gross income for the taxable year must be “qualifying income.” The Fund anticipates treating the income and gain generated from investments in controlled foreign subsidiaries that invest in physical commodities and/or commodity-linked derivative instruments as “qualifying income” for regulated investment company qualification purposes. However, there can be no assurance that the IRS will agree with treating such income and gain as “qualifying income.” If the IRS makes an adverse determination relating to the treatment of such income and gain, the Fund would likely need to change its investment strategies, which could adversely affect the Fund. The IRS has proposed regulations that, if finalized in current form, would specify that a subpart F income inclusion for U.S. federal income tax purposes will be treated as qualifying income only to the extent that the Subsidiary makes distributions out of its earnings and profits in the same taxable year.
Risk Lose Money [Text]	rr_RiskLoseMoney	You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The information shows you how the Fund’s performance has varied for the periods since inception and provides some indication of the risks of investing in the Fund. Class K Shares do not have a performance history as of the date of this prospectus. As a result, the chart and the table give you a picture of the long-term performance for Institutional Shares of the Fund, which are not offered in this prospectus. The performance of Class K Shares would be substantially similar to Institutional Shares because Class K Shares and Institutional Shares are invested in the same portfolio of securities and performance would differ only to the extent that Institutional Shares and Class K Shares have different expenses. The actual returns of Class K Shares would have been higher than those of the Institutional Shares because Class K Shares have lower expenses than the Institutional Shares. The table compares the Fund’s performance to that of the Bloomberg Commodity Index Total ReturnSM. 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 http://www.blackrock.com or can be obtained by phone at (800) 882-0052.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The information shows you how the Fund’s performance has varied for the periods since inception and provides some indication of the risks of investing in the Fund.
Performance One Year or Less [Text]	rr_PerformanceOneYearOrLess	Class K Shares do not have a performance history as of the date of this prospectus.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	(800) 882-0052
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	http://www.blackrock.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	As with all such investments, past performance (before and after taxes) is not an indication of future results.
Bar Chart [Heading]	rr_BarChartHeading	Institutional Shares ANNUAL TOTAL RETURNS BlackRock Commodity Strategies Fund As of 12/31
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the bar chart, the highest return for a quarter was 12.88% (quarter ended June 30, 2016) and the lowest return for a quarter was –17.55% (quarter ended September 30, 2015).
Bar Chart, Returns for Class Not Offered in Prospectus [Text]	rr_BarChartReturnsForClassNotOfferedInProspectus	Class K Shares do not have a performance history as of the date of this prospectus. As a result, the chart and the table give you a picture of the long-term performance for Institutional Shares of the Fund, which are not offered in this prospectus.
Performance Table Heading	rr_PerformanceTableHeading	As of 12/31/17 Average Annual Total Returns
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	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	rr_PerformanceTableNotRelevantToTaxDeferred	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	rr_PerformanceTableNarrativeTextBlock	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.
BlackRock Commodity Strategies Fund | Class K Shares
Risk/Return:	rr_RiskReturnAbstract
Management Fee	rr_ManagementFeesOverAssets	0.90%	[1]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Miscellaneous Expenses	rr_Component1OtherExpensesOverAssets	0.26%
Other Expenses of the Subsidiary	rr_Component2OtherExpensesOverAssets		[2],[3]
Other Expenses	rr_OtherExpensesOverAssets	0.26%	[2],[3]
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.04%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.20%
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.22%)	[1],[4]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	0.98%	[1],[4]
1 Year	rr_ExpenseExampleYear01	$ 100
3 Years	rr_ExpenseExampleYear03	359
5 Years	rr_ExpenseExampleYear05	638
10 Years	rr_ExpenseExampleYear10	$ 1,435
BlackRock Commodity Strategies Fund | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
2012	rr_AnnualReturn2012	(1.05%)
2013	rr_AnnualReturn2013	(7.09%)
2014	rr_AnnualReturn2014	(14.08%)
2015	rr_AnnualReturn2015	(24.94%)
2016	rr_AnnualReturn2016	23.18%
2017	rr_AnnualReturn2017	8.28%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2016
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	12.88%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(17.55%)
1 Year	rr_AverageAnnualReturnYear01	8.28%
5 Years	rr_AverageAnnualReturnYear05	(4.39%)
Since Inception	rr_AverageAnnualReturnSinceInception	(2.88%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 03, 2011
BlackRock Commodity Strategies Fund | Return After Taxes on Distributions | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	8.11%
5 Years	rr_AverageAnnualReturnYear05	(4.46%)
Since Inception	rr_AverageAnnualReturnSinceInception	(3.08%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 03, 2011
BlackRock Commodity Strategies Fund | Return After Taxes on Distributions and Sale of Fund Shares | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	4.82%
5 Years	rr_AverageAnnualReturnYear05	(3.27%)
Since Inception	rr_AverageAnnualReturnSinceInception	(2.18%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 03, 2011
BlackRock Commodity Strategies Fund | Bloomberg Commodity Index Total Return℠ (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.70%
5 Years	rr_AverageAnnualReturnYear05	(8.45%)
Since Inception	rr_AverageAnnualReturnSinceInception	(6.95%)

[1] As described in the “Management of the Fund” section of the Fund’s prospectus beginning on page 32, BlackRock Advisors, LLC (“BlackRock”) has contractually agreed to waive the management fee with respect to any portion of the Fund’s assets estimated to be attributable to investments in other equity and fixed-income mutual funds and exchange-traded funds managed by BlackRock or its affiliates that have a contractual management fee, through November 30, 2019. The contractual agreement may be terminated upon 90 days’ notice by a majority of the non-interested trustees of the Trust or by a vote of a majority of the outstanding voting securities of the Fund.

[2] Other Expenses are based on estimated amounts for the current year.

[3] The Other Expenses of the BlackRock Cayman Commodity Strategies Fund, Ltd. (the “Subsidiary”) were less than 0.01% for the most recent fiscal year.

[4] As described in the “Management of the Fund” section of the Fund’s prospectus beginning on page 32, BlackRock has contractually agreed to waive and/or reimburse fees or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 0.94% of average daily net assets through November 30, 2019. The Fund may have to repay some of these waivers and/or reimbursements to BlackRock in the following two years. The contractual agreement may be terminated upon 90 days’ notice by a majority of the non-interested trustees of the Trust or by a vote of a majority of the outstanding voting securities of the Fund.