Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	BLACKROCK FUNDS
Prospectus Date	rr_ProspectusDate	Nov. 28, 2018
Investor A, C and Institutional | BlackRock Advantage Emerging Markets Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Overview <br/><br/> <b>Key Facts About BlackRock Advantage Emerging Markets Fund </b>
Objective [Heading]	rr_ObjectiveHeading	<b>Investment Objective </b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The investment objective of BlackRock Advantage Emerging Markets Fund (the “Fund”), a series of BlackRock FundsSM (the “Trust”), is to seek long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	<b>Fees and Expenses of the Fund </b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in the fund complex advised by BlackRock Advisors, LLC (“BlackRock”) or its affiliates. More information about these and other discounts is available from your financial professional or your selected securities dealer, broker, investment adviser, service provider or industry professional (including BlackRock and its affiliates) (each a “Financial Intermediary”) and in the “Details About the Share Classes” and the “Intermediary-Defined Sales Charge Waiver Policies” sections on pages 22 and A-1, respectively, of the Fund’s prospectus and in the “Purchase of Shares” section on page II-73 of Part II of the Fund’s Statement of Additional Information.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<b>Shareholder Fees<br/> (fees paid directly from your investment) </b>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>Annual Fund Operating Expenses<br/> (expenses that you pay each year as a<br/> percentage of the value of your investment) </b>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	November 30, 2019
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>Portfolio Turnover: </b>
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 111% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	111.00%
Expenses Deferred Charges [Text Block]	rr_ExpensesDeferredChargesTextBlock	A contingent deferred sales charge (“CDSC”) of 1.00% is assessed on certain redemptions of Investor A Shares made within 18 months after purchase where no initial sales charge was paid at time of purchase as part of an investment of $1,000,000 or more.
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $25,000 in the fund complex advised by BlackRock Advisors, LLC (“BlackRock”) or its affiliates.
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	$ 25,000
Expenses Restated to Reflect Current [Text]	rr_ExpensesRestatedToReflectCurrent	Other Expenses have been restated to reflect current fees.
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent annual report, which do not include Acquired Fund Fees and Expenses or the restatement of Other Expenses to reflect current fees.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>Example: </b>
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:
Expense Example, No Redemption, By Year, Caption [Text]	rr_ExpenseExampleNoRedemptionByYearCaption	You would pay the following expenses if you did not redeem your shares:
Strategy [Heading]	rr_StrategyHeading	<b>Principal Investment Strategies of the Fund </b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	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 issued by, or tied economically to, companies in emerging markets and derivatives that have similar economic characteristics to such securities. BlackRock considers an emerging market country to include any country that is: (1) generally recognized to be an emerging market country by the international financial community, including the World Bank; (2) classified by the United Nations as a developing country; or (3) included in the MSCI Emerging Markets Index (the “MSCI EM Index”). BlackRock determines that an investment is tied economically to an emerging market if such investment satisfies one or more of the following conditions: (1) the issuer’s primary trading market is in an emerging market; (2) the issuer is organized under the laws of, derives at least 50% of its revenue from, or has at least 50% of its assets in emerging markets; (3) the investment is included in an index representative of emerging markets; and (4) the investment is exposed to the economic risks and returns of emerging markets. The Fund primarily intends to invest in equity securities, which include common stock, preferred stock and convertible securities, or other financial instruments that are components of, or have characteristics similar to, the securities included in the MSCI EM Index. The MSCI EM Index is a capitalization-weighted index from a broad range of industries chosen for market size, liquidity and industry group representation. The Fund primarily seeks to buy common stock and may also invest in preferred stock and convertible securities. From time to time, the Fund may invest in shares of companies through “new issues” or initial public offerings (“IPOs”). 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 currency or an index, including but not limited to the MSCI EM Index. The use of 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 can be effective in protecting or enhancing the value of the Fund’s assets.
Risk [Heading]	rr_RiskHeading	<b>Principal Risks of Investing in the Fund </b>
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 the principal risks of investing in the Fund. Commodities Related Investments Risk — Exposure to the commodities markets may subject the Fund to greater volatility than investments in traditional securities. The value of commodity-linked derivative investments may be affected by changes in overall market movements, commodity index volatility, changes in interest rates, or factors affecting a particular industry or commodity, such as drought, floods, weather, embargoes, tariffs and international economic, political and regulatory developments. 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 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. Depositary Receipts Risk — Depositary receipts are generally subject to the same risks as the foreign securities that they evidence or into which they may be converted. In addition to investment risks associated with the underlying issuer, depositary receipts expose the Fund to additional risks associated with the non-uniform terms that apply to depositary receipt programs, credit exposure to the depository bank and to the sponsors and other parties with whom the depository bank establishes the programs, currency risk and liquidity risk. The issuers of unsponsored depositary receipts are not obligated to disclose information that is, in the United States, considered material. Therefore, there may be less information available regarding these issuers and there may not be a correlation between such information and the market value of the depositary receipts. 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 Wall Street Reform and Consumer Protection Act (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. To the extent derivatives are utilized to implement the Fund’s investment strategies, these transactions involve the risks described below with respect to investments in emerging market securities. 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. 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. 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. “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. 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. 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.
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	<b>Performance Information </b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	Effective June 12, 2017, the Fund changed its name, investment objective, investment process and investment strategies. Performance for the periods prior to June 12, 2017 shown below is based on the investment process and investment strategies utilized by the Fund prior to June 12, 2017 under the name “BlackRock Emerging Markets Long/Short Equity Fund.” 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 EM Index. To the extent that dividends and distributions have been paid by the Fund, the performance information of 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. Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown. However, the table includes all applicable fees and sales charges. 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 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]	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	<b>Investor A Shares <br/>ANNUAL TOTAL RETURNS <br/>BlackRock Advantage Emerging Markets Fund <br/>As of 12/31 </b>
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	Sales charges are not reflected in the bar chart. If they were, returns would be less than those shown.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the bar chart, the highest return for a quarter was 7.36% (quarter ended September 30, 2017) and the lowest return for a quarter was -4.21% (quarter ended March 31, 2014). The year-to-date return as of September 30, 2018 was -7.50%.
Performance Table Heading	rr_PerformanceTableHeading	<b>As of 12/31/17<br/>Average Annual Total Returns</b>
Performance Table Does Reflect Sales Loads	rr_PerformanceTableDoesReflectSalesLoads	However, the table includes all applicable fees and sales charges.
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 One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns are shown for Investor A Shares only, and the after-tax returns for Investor C and Institutional Shares will vary.
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. After-tax returns are shown for Investor A Shares only, and the after-tax returns for Investor C and Institutional Shares will vary.
Investor A, C and Institutional | BlackRock Advantage Emerging Markets Fund | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	5.25%
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none	[1]
Management Fee	rr_ManagementFeesOverAssets	0.89%	[2],[3]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.43%	[4],[5]
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.07%	[5]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.64%	[5]
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.38%)	[2],[3]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	1.26%	[2],[3]
1 Year	rr_ExpenseExampleYear01	$ 647
3 Years	rr_ExpenseExampleYear03	980
5 Years	rr_ExpenseExampleYear05	1,336
10 Years	rr_ExpenseExampleYear10	$ 2,336
2012	rr_AnnualReturn2012	7.25%
2013	rr_AnnualReturn2013	(1.30%)
2014	rr_AnnualReturn2014	(2.30%)
2015	rr_AnnualReturn2015	(6.55%)
2016	rr_AnnualReturn2016	1.38%
2017	rr_AnnualReturn2017	14.32%
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2018
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	(7.50%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	highest return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2017
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	7.36%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	lowest return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2014
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(4.21%)
1 Year	rr_AverageAnnualReturnYear01	8.31%
5 Years	rr_AverageAnnualReturnYear05	(0.21%)
Since Inception	rr_AverageAnnualReturnSinceInception	0.91%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 06, 2011
Investor A, C and Institutional | BlackRock Advantage Emerging Markets Fund | Investor C Shares
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOfferingPrice	1.00%	[6]
Management Fee	rr_ManagementFeesOverAssets	0.89%	[2],[3]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses	rr_OtherExpensesOverAssets	0.49%	[4],[5]
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.07%	[5]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	2.45%	[5]
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.44%)	[2],[3]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	2.01%	[2],[3]
1 Year	rr_ExpenseExampleYear01	$ 304
3 Years	rr_ExpenseExampleYear03	722
5 Years	rr_ExpenseExampleYear05	1,266
10 Years	rr_ExpenseExampleYear10	2,753
1 Year	rr_ExpenseExampleNoRedemptionYear01	204
3 Years	rr_ExpenseExampleNoRedemptionYear03	722
5 Years	rr_ExpenseExampleNoRedemptionYear05	1,266
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 2,753
1 Year	rr_AverageAnnualReturnYear01	12.43%
5 Years	rr_AverageAnnualReturnYear05	0.09%
Since Inception	rr_AverageAnnualReturnSinceInception	1.00%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 06, 2011
Investor A, C and Institutional | BlackRock Advantage Emerging Markets Fund | Institutional Shares
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of offering price or redemption proceeds, whichever is lower)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none
Management Fee	rr_ManagementFeesOverAssets	0.89%	[2],[3]
Distribution and/or Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.40%	[4],[5]
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.07%	[5]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.36%	[5]
Fee Waivers and/or Expense Reimbursements	rr_FeeWaiverOrReimbursementOverAssets	(0.35%)	[2],[3]
Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements	rr_NetExpensesOverAssets	1.01%	[2],[3]
1 Year	rr_ExpenseExampleYear01	$ 103
3 Years	rr_ExpenseExampleYear03	396
5 Years	rr_ExpenseExampleYear05	711
10 Years	rr_ExpenseExampleYear10	$ 1,605
1 Year	rr_AverageAnnualReturnYear01	14.69%
5 Years	rr_AverageAnnualReturnYear05	1.10%
Since Inception	rr_AverageAnnualReturnSinceInception	2.03%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 06, 2011
Investor A, C and Institutional | BlackRock Advantage Emerging Markets Fund | Return After Taxes on Distributions | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	8.31%
5 Years	rr_AverageAnnualReturnYear05	(0.30%)
Since Inception	rr_AverageAnnualReturnSinceInception	0.82%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 06, 2011
Investor A, C and Institutional | BlackRock Advantage Emerging Markets Fund | Return After Taxes on Distributions and Sale of Fund Shares | Investor A Shares
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	4.71%
5 Years	rr_AverageAnnualReturnYear05	(0.18%)
Since Inception	rr_AverageAnnualReturnSinceInception	0.68%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 06, 2011
Investor A, C and Institutional | BlackRock Advantage Emerging Markets Fund | MSCI EM Index (Reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	37.28%
5 Years	rr_AverageAnnualReturnYear05	4.35%
Since Inception	rr_AverageAnnualReturnSinceInception	7.35%

[1] A contingent deferred sales charge (“CDSC”) of 1.00% is assessed on certain redemptions of Investor A Shares made within 18 months after purchase where no initial sales charge was paid at time of purchase as part of an investment of $1,000,000 or more.

[2] As described in the “Management of the Fund” section of the Fund’s prospectus beginning on page 37, 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) as a percentage of average daily net assets to 1.19% (for Investor A Shares), 1.94% (for Investor C Shares), and 0.94% (for Institutional Shares) 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.

[3] As described in the “Management of the Fund” section of the Fund’s prospectus beginning on page 37, 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.

[4] Other Expenses have been restated to reflect current fees.

[5] Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent annual report, which do not include Acquired Fund Fees and Expenses or the restatement of Other Expenses to reflect current fees.

[6] There is no CDSC on Investor C Shares after one year.