XML 186 R23.htm IDEA: XBRL DOCUMENT v3.21.2
Label Element Value
iShares Morningstar Multi-Asset Income ETF  
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading iSHARES® MORNINGSTAR MULTI-ASSET INCOME ETF Ticker: IYLD Stock Exchange: Cboe BZX
Objective [Heading] rr_ObjectiveHeading Investment Objective
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
The iShares Morningstar Multi-Asset Income ETF (the “Fund”) seeks to track the investment results of an index composed of underlying equity, fixed income and other income funds that collectively seek to deliver high current income while providing an opportunity for capital appreciation.
Expense [Heading] rr_ExpenseHeading Fees and Expenses
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
The following table describes the fees and expenses that you will incur if you buy, hold and sell shares of the Fund. The investment advisory agreement between iShares Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and any extraordinary expenses.  The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”). BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fee in order to limit the Fund’s total annual fund operating expenses after fee waiver to 0.60% through November 30, 2026. The contractual waiver may be terminated prior to November 30, 2026 only upon written agreement of the Trust and BFA.
You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Operating Expenses Caption [Text] rr_OperatingExpensesCaption Annual Fund Operating Expenses(ongoing expenses that you pay each year as apercentage of the value of your investments)
Fee Waiver or Reimbursement over Assets, Date of Termination rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination November 30, 2026
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading Portfolio Turnover. 
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock The Fund and the underlying funds in which the Fund invests (each, an “Underlying Fund” and collectively, the “Underlying Funds”), may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate for the Fund or Underlying Funds may indicate higher transaction costs and may cause the Fund or the Underlying Funds to incur increased expenses. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example (except costs to Underlying Funds included as part of Acquired Fund Fees and Expenses), affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 94% of the average value of its portfolio. To the extent the Underlying Fund incurs costs from high portfolio turnover, such costs may have a negative effect on the performance of the Fund.
Portfolio Turnover, Rate rr_PortfolioTurnoverRate 94.00%
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text] rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”).
Expense Example [Heading] rr_ExpenseExampleHeading Example. 
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell 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
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
The Fund is a fund-of-funds and seeks to achieve its investment objective by investing primarily in the securities of the Underlying Funds that themselves seek investment results corresponding to their own underlying indexes. The Fund invests in a combination of Underlying Funds and may also invest in other exchange-traded funds (“ETFs”) (including other iShares funds), U.S. government securities, short-term paper, futures contracts, options on futures contracts, options, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates (“BlackRock Cash Funds”).
The Morningstar® Multi-Asset High Income IndexSM (the “Underlying Index”) is broadly diversified and seeks to deliver high current income while maintaining long-term capital appreciation.  The goal of the Underlying Index is to represent an allocation strategy to distinct asset classes of 20% equities, 60% fixed-income and 20% in an “alternative income sources” asset class, which consists of Underlying Funds that the index provider, Morningstar, Inc. (“Morningstar” or the “Index Provider”), considers to exhibit both equity and fixed-income-like characteristics. Each asset class has its own risk profile. The Underlying Index is rebalanced and reconstituted quarterly. The Underlying Index is comprised of Underlying Funds within these asset classes that have demonstrated relatively high income on a consistent basis and meet liquidity characteristics as determined by Morningstar's proprietary index methodology.
The 20% equity allocation consists of Underlying Funds that invest primarily in U.S. and non-U.S. equities. The 60% fixed-income allocation consists of Underlying Funds that invest primarily in U.S. and non-U.S. fixed-income securities. The 20% alternative income source allocation generally consists of Underlying Funds that invest primarily in real estate investment trusts (“REITs”) and preferred stocks. When the combined allocation percentages equal less than 100%, the Fund may invest the remainder of its assets in BlackRock Cash Funds. Investments in Underlying Funds that have significant non-U.S. currency exposure will not exceed 25% of the weight of the Underlying Index.
As of July 31, 2021, the Underlying Index included the following Underlying Funds within the equity asset class: iShares Core High Dividend ETF, iShares Emerging Markets Dividend ETF 
and iShares International Select Dividend ETF; the following Underlying Funds within the fixed-income asset class: iShares 10-20 Year Treasury Bond ETF, iShares 20+ Year Treasury Bond ETF, iShares 7-10 Year Treasury Bond ETF, iShares iBoxx $ High Yield Corporate Bond ETF, iShares J.P. Morgan EM Local Currency Bond ETF, iShares J.P. Morgan USD Emerging Markets Bond ETF and iShares MBS ETF; and the following Underlying Funds within the alternatives asset class: iShares Mortgage Real Estate ETF, iShares Preferred and Income Securities ETF and iShares U.S. Real Estate ETF. The Underlying Index may add, eliminate or replace Underlying Funds at any time. As of July 31, 2021, a significant portion of the Underlying Index is represented by securities of companies in the financials industry or sector. The components of the Underlying Index are likely to change over time. 
BFA uses a “passive” or indexing approach to try to achieve the Fund’s investment objective. Unlike many investment companies, the Fund does not try to “beat” the index it tracks and does not seek temporary defensive positions when markets decline or appear overvalued. 
Indexing may eliminate the chance that the Fund will substantially outperform the Underlying Index but also may reduce some of the risks of active management, such as poor security selection. Indexing seeks to achieve lower costs and better after-tax performance by aiming to keep portfolio turnover low in comparison to actively managed investment companies. 
BFA uses a representative sampling indexing strategy to manage the Fund. “Representative sampling” is an indexing strategy that involves investing in a representative sample of securities that collectively has an investment profile similar to that of an applicable underlying index. The securities selected are expected to have, in the aggregate, investment characteristics (based on factors such as market capitalization and industry weightings), fundamental characteristics (such as return variability and yield) and liquidity measures similar to those of an applicable underlying index. The Fund and an Underlying Fund may or may not hold all of the securities in the applicable Underlying Index. 
The Fund generally will invest at least 80% of its assets in the component securities of its Underlying Index and in investments that have economic characteristics that are substantially identical to the component securities of its Underlying Index (i.e., depositary receipts representing securities of the Underlying Index) and may invest up to 20% of its assets in certain futures, options and swap contracts, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates, as well as in securities not included in the Underlying Index, but which BFA believes will help the Fund track the Underlying Index. Cash and cash equivalent investments associated with a derivative position will be treated as part of that position for the purposes of calculating investments not included in the Underlying Index. The Fund seeks to track the investment results of the Underlying Index before fees and expenses of the Fund. 
The Fund may lend securities representing up to one-third of the value of the Fund's total assets (including the value of any collateral received). 
The Underlying Index is sponsored by Morningstar, which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the securities in the Underlying Index and publishes information regarding the market value of the Underlying Index. 
Industry Concentration Policy. The Fund will concentrate its investments (i.e., hold 25% or more of its total assets) in a particular industry or group of industries to approximately the same extent that the Underlying Index is concentrated. For purposes of this limitation, securities of the U.S. government (including its agencies and instrumentalities) and repurchase agreements collateralized by U.S. government securities are not considered to be issued by members of any industry. 
Strategy Portfolio Concentration [Text] rr_StrategyPortfolioConcentration Industry Concentration Policy. The Fund will concentrate its investments (i.e., hold 25% or more of its total assets) in a particular industry or group of industries to approximately the same extent that the Underlying Index is concentrated. For purposes of this limitation, securities of the U.S. government (including its agencies and instrumentalities) and repurchase agreements collateralized by U.S. government securities are not considered to be issued by members of any industry. 
Risk [Heading] rr_RiskHeading Summary of Principal Risks
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below (either directly or through its investments in the Underlying Funds), any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. The order of the below risk factors does not indicate the significance of any particular risk factor.
Affiliated Fund Risk. In managing the Fund, BFA will have the ability to select Underlying Funds and substitute other ETFs which it believes will achieve the Fund’s objective. BFA may be subject to potential conflicts of interest in selecting Underlying Funds and substituting other ETFs because the fees paid to BFA by some Underlying Funds and other ETFs managed by BFA may be higher than the fees paid by other Underlying Funds. If an Underlying Fund or other ETF holds interests in an affiliated fund in excess of a certain amount, the Fund may be prohibited from purchasing shares of that Underlying Fund or other ETF.
Allocation Risk. The Fund’s ability to achieve its investment objective depends upon BFA's ability to develop a model that accurately assesses the Fund’s asset class allocation and selects the best mix of Underlying Funds and other ETFs. There is a risk that BFA's evaluations and assumptions regarding asset classes or Underlying Funds, which are utilized as inputs in the model, may be incorrect in view of actual market conditions.
Asset Class Risk. Securities and other assets in the Underlying Index or in the Fund's or an Underlying Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes.
Authorized Participant Concentration Risk.  Only an Authorized Participant (as defined in the Creations and Redemptions section of this prospectus (the “Prospectus”)) may engage in creation or redemption transactions directly with the Fund, and none of those Authorized Participants is obligated to engage in creation and/or redemption transactions. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to 
proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem, Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes. 
Calculation Methodology Risk. The Underlying Index relies on various sources of information to assess the criteria of issuers included in the Underlying Index, including information that may be based on assumptions and estimates. Neither the Fund nor BFA can offer assurances that the Underlying Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. 
Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund or an Underlying Fund may “call” or repay the security before its stated maturity, and the Fund or an Underlying Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's income, or in securities with greater risks or with other less favorable features. 
Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's or an Underlying Fund's investments are concentrated in the securities and/or other assets of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector, market segment or asset class. 
Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s or an Underlying Fund's investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation. 
Currency Risk. Because the Fund's and the Underlying Funds' NAVs are determined in U.S. dollars, the Fund's NAV could decline if the currency of a non-U.S. market in which the Fund or an Underlying Fund invests depreciates against the U.S. dollar or if there are delays or limits on repatriation of such currency. Currency exchange rates can be very volatile and can change quickly and unpredictably. As a result, the Fund's NAV may change quickly and without warning. 
Cybersecurity Risk. Failures or breaches of the electronic systems of the Fund or the Underlying Funds, the Funds' or the Underlying Funds' adviser, distributor, the Index Provider and other service providers, market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions, negatively impact the Fund’s business operations and/or potentially result in financial losses to the Fund 
and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cybersecurity plans and systems of the Fund’s Index Provider and other service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests. 
Equity Securities Risk. Equity securities are subject to changes in value, and their values may be more volatile than those of other asset classes. The Underlying Index is composed of common stocks, which generally subject their holders to more risks than preferred stocks and debt securities because common stockholders’ claims are subordinated to those of holders of preferred stocks and debt securities upon the bankruptcy of the issuer. 
Financials Sector Risk. Performance of companies in the financials sector may be adversely impacted by many factors, including, among others, changes in government regulations, economic conditions, and interest rates, credit rating downgrades, and decreased liquidity in credit markets. The extent to which an Underlying Fund may invest in a company that engages in securities-related activities or banking is limited by applicable law. The impact of changes in capital requirements and recent or future regulation of any individual financial company, or of the financials sector as a whole, cannot be predicted. In recent years, cyberattacks and technology malfunctions and failures have become increasingly frequent in this sector and have caused significant losses to companies in this sector, which may negatively impact an Underlying Fund. 
Geographic Risk. A natural disaster could occur in a geographic region in which the Fund or an Underlying Fund invests, which could adversely affect the economy or the business operations of companies in the specific geographic region, causing an adverse impact on the Fund's or an Underlying Fund's investments in, or which are exposed to, the affected region. 
High Yield Securities Risk. Securities that are rated below investment-grade (commonly referred to as “junk bonds,” which may include those bonds rated below “BBB-” by S&P Global Ratings, a subsidiary of S&P Global, Inc. (“S&P Global Ratings”) and Fitch Ratings, Inc. (“Fitch”) or below “Baa3” by Moody's Investors Service, Inc. (“Moody's”)), or are unrated, may be deemed speculative, may involve greater levels of risk than higher-rated securities of similar maturity and may be more likely to default. 
Income Risk. The Fund's income may decline if interest rates fall. This decline in income can occur because the Fund or an Underlying Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, bonds in the Underlying Index are substituted, or the Fund or an Underlying Fund otherwise needs to purchase additional bonds. 
Index-Related Risk. There is no guarantee that the Fund’s investment results will have a high degree of correlation to those of the Underlying Index or that the Fund will achieve its investment objective. Market disruptions and regulatory restrictions could have an adverse effect on the Fund’s ability to adjust its exposure to the required levels in order to track the Underlying Index. Errors in index data, index computations or the construction of the Underlying Index in accordance with its methodology may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, which may have an adverse impact on the Fund and its shareholders. Unusual market conditions may cause the Index Provider to postpone a scheduled rebalance, which could cause the Underlying Index to vary from its normal or expected composition. 
Infectious Illness Risk. An outbreak of an infectious respiratory illness, COVID-19, caused by a novel coronavirus has resulted in travel restrictions, disruption of healthcare systems, prolonged quarantines, cancellations, supply chain disruptions, lower consumer demand, layoffs, ratings downgrades, defaults and other significant economic impacts. Certain markets have experienced temporary closures, extreme volatility, severe losses, reduced liquidity and increased trading costs. These events will have an impact on the Fund and its investments and could impact the Fund’s ability to purchase or sell securities or cause elevated tracking error and increased premiums or discounts to the Fund's NAV. Other infectious illness outbreaks in the future may result in similar impacts. 
Interest Rate Risk. During periods of very low or negative interest rates, the Fund may be unable to maintain positive returns or pay dividends to Fund shareholders. Very low or negative interest rates may magnify interest rate risk. Changing interest rates, including rates that fall below zero, may have unpredictable effects on markets, result in heightened market volatility and detract from the Fund’s performance to the extent the Fund is exposed to such interest rates. Additionally, under certain market conditions in which interest rates are low and the market prices for portfolio securities have increased, the Fund may have a very low or even negative yield. A low or negative yield would cause the Fund to lose money in certain conditions and over certain time periods. An increase in interest rates will generally cause the value of securities held by the Fund  or an Underlying Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments, including those held by the Fund. The historically low interest rate environment heightens the risks associated with rising interest rates. 
Investment in Underlying Funds Risk. The Fund expects to invest substantially all of its assets in the Underlying Funds, so the Fund’s investment performance is directly related to the performance of the Underlying Funds. The Fund’s NAV will change with changes in the value of the Underlying Funds and other securities in which the Fund invests based on their market valuations. An investment in the Fund will entail more costs and expenses than a direct investment in the Underlying Funds. 
As the Underlying Funds, or the Fund’s allocations among the Underlying Funds, change from time to time, or to the extent that the total annual fund operating expenses of any Underlying Fund change, the weighted average operating expenses borne by the Fund may increase or decrease. 
Issuer Risk. The performance of the Fund depends on the performance of individual securities to which the Fund and the Underlying Funds have exposure. Changes in the financial condition or credit rating of an issuer of those securities may cause the value of the securities to decline. 
Large-Capitalization Companies Risk. Large-capitalization companies may be less able than smaller capitalization companies to adapt to changing market conditions. Large-capitalization companies may be more mature and subject to more limited growth potential compared with smaller capitalization companies. During different market cycles, the performance of large-capitalization companies has trailed the overall performance of the broader securities markets. 
Management Risk. As the Fund will not fully replicate the Underlying Index, it is subject to the risk that BFA's investment strategy may not produce the intended results. 
Market Risk. The Fund and the Underlying Funds could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Local, regional or global events such as war, acts of terrorism, the spread of infectious illness or other public health issues, recessions, or other events could have a significant impact on the Fund and its investments and could result in increased premiums or discounts to the Fund’s NAV. 
Market Trading Risk. The Fund and the Underlying Funds face numerous market trading risks, including the potential lack of an active market for their shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S OR THE UNDERLYING FUNDS' SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. 
Model Risk. Neither the Fund nor BFA can offer assurances that the Underlying Index's allocation model will achieve its intended results or maximize returns or minimize risk, or be appropriate for every investor seeking a particular risk profile. 
Operational Risk. The Fund and the Underlying Funds are exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third parties, failed or inadequate processes and technology or systems failures. The Fund, the Underlying Funds and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks. 
Passive Investment Risk. The Fund and the Underlying Funds are not actively managed, and BFA generally does not attempt to take defensive positions under any market conditions, including declining markets. 
Reinvestment Risk. The Fund  or an Underlying Fund may invest a portion of its assets in short-term fixed-income instruments and, as a result, may be adversely affected if interest rates fall because they may have to invest in lower-yielding bonds as bonds mature. 
Reliance on Trading Partners Risk. The Fund or an Underlying Fund invests in countries or regions whose economies are heavily dependent upon trading with key partners. Any reduction in this trading may have an adverse impact on the Fund's investments. 
Risk of Investing in Russia. Investing in Russian securities involves significant risks, including legal, regulatory, currency and economic risks that are specific to Russia. In addition, investing in Russian securities involves risks associated with the settlement of portfolio transactions and loss of the Fund’s ownership rights in its portfolio securities as a result of the system of share registration and custody in Russia. A number of jurisdictions, including the U.S., Canada and the European Union (the “EU”), have imposed economic sanctions on certain Russian individuals and Russian corporate entities. Additionally, Russia is alleged to have participated in state-sponsored cyberattacks against foreign companies and foreign governments. Actual and threatened responses to such activity, including purchasing restrictions, sanctions, tariffs or cyberattacks on the Russian government or Russian companies, may impact Russia’s economy and Russian issuers of securities in which an Underlying Fund invests. 
Risk of Investing in Saudi Arabia. The ability of foreign investors (such as the Fund or an Underlying Fund) to invest in the securities of Saudi Arabian issuers is relatively new. Such ability could be restricted by the Saudi Arabian government at any time, and unforeseen risks could materialize with respect to foreign ownership in such securities. The economy of Saudi Arabia is dominated by petroleum exports. A sustained decrease in petroleum prices could have a negative impact on all aspects of the economy. Investments in the securities of Saudi Arabian issuers involve risks not typically associated with investments in securities of issuers in more developed countries that may negatively affect the value of the Fund’s investments. Such heightened risks may include, among others, expropriation and/or nationalization of assets, restrictions on and government intervention in international trade, confiscatory taxation, political instability, including authoritarian and/or military involvement in governmental decision making, armed conflict, crime and instability as a result of religious, ethnic and/or socioeconomic unrest. There remains the possibility that instability in the larger Middle East region could adversely impact the economy of Saudi Arabia, and there is no assurance of political stability in Saudi Arabia. 
Saudi Arabia Broker Risk.  There are a number of different ways of conducting transactions in equity securities in the Saudi Arabian market.  The Fund generally expects to conduct its transactions in a manner in which the Fund would not be limited 
by Saudi Arabian regulations to a single broker. However, there may be a limited number of brokers who can provide services to the Fund, which may have an adverse impact on the prices, quantity or timing of Fund transactions. 
Risk of Investing in the U.S. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund or the Underlying Funds have exposure. 
Savings Associations Risk. Savings associations are affected by extensive regulations, interest rates, loan losses, decreased availability of money or asset valuation and market conditions. The historically low interest rate environment has created certain risks to savings associations as they continue to re-evaluate their business models and risk appetites to generate returns. 
Securities Lending Risk. The Fund  or an Underlying Fund may engage in securities lending. Securities lending involves the risk that the Fund or the Underlying Funds may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund or the Underlying Funds could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund. 
Sovereign and Quasi-Sovereign Obligations Risk. An Underlying Fund may invest in securities issued by or guaranteed by non-U.S. sovereign governments, which may be unable or unwilling to repay principal or interest when due. In times of economic uncertainty, the prices of these securities may be more volatile than those of corporate debt obligations or of other government debt obligations. 
Tax Risk. Because the Fund is expected to invest in the Underlying Funds, the Fund’s realized losses on sales of shares of an Underlying Fund may be indefinitely or permanently deferred as “wash sales.” Distributions of short-term capital gains by an Underlying Fund will be recognized as ordinary income by the Fund and would not be offset by the Fund’s capital loss carryforwards, if any. Capital loss carryforwards of an Underlying Fund, if any, would not offset net capital gains of the Fund. 
Tracking Error Risk. The Fund and the Underlying Funds may be subject to tracking error, which is the divergence of the Fund’s performance from that of the Underlying Index. Tracking error may occur because of differences between the securities and 
other instruments held in the Fund’s portfolio and those included in the Underlying Index, pricing differences (including, as applicable, differences between a security’s price at the local market close and the Fund's valuation of a security at the time of calculation of the Fund's NAV), transaction costs incurred by the Fund, the Fund’s holding of uninvested cash, differences in timing of the accrual of or the valuation of dividends or interest received by the Fund or distributions paid to the Fund’s or an Underlying Fund’s shareholders, the requirements to maintain pass-through tax treatment, portfolio transactions carried out to minimize the distribution of capital gains to shareholders, acceptance of custom baskets, changes to the Underlying Index or the costs to the Fund and an underlying fund of complying with various new or existing regulatory requirements. This risk may be heightened during times of increased market volatility or other unusual market conditions. Tracking error also may result because the Fund and an underlying fund incurs fees and expenses, while the Underlying Index does not. The underlying funds are also subject to tracking error risk in seeking to track their own performance of the applicable underlying indexes. 
U.S. Government Issuers Risk. Obligations of U.S. government agencies and authorities are supported by varying degrees of credit, but generally are not backed by the full faith and credit of the U.S. government. Similar to other issuers, changes to the financial condition or credit rating of the U.S. government or U.S. government agencies and authorities may cause the value of the Fund's investments to decline. 
Valuation Risk. The price the Fund  or an Underlying Fund could receive upon the sale of a security or other asset may differ from the Fund's or the Underlying Fund's valuation of the security or other asset and from the value used by the Underlying Index, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's or an Underlying Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's or an Underlying Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or used a different valuation methodology. The Fund’s or an Underlying Fund's ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers. 
Risk Lose Money [Text] rr_RiskLoseMoney As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading Performance Information
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.
Performance Information Illustrates Variability of Returns [Text] rr_PerformanceInformationIllustratesVariabilityOfReturns The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund.
Performance Availability Phone [Text] rr_PerformanceAvailabilityPhone 1-800-iShares (1-800-474-2737) (toll free)
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.iShares.com
Performance Past Does Not Indicate Future [Text] rr_PerformancePastDoesNotIndicateFuture Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.
Bar Chart [Heading] rr_BarChartHeading Year by Year Returns1 (Years Ended December 31)
Bar Chart Closing [Text Block] rr_BarChartClosingTextBlock
The best calendar quarter return during the periods shown above was 12.54% in the 2nd quarter of 2020; the worst was -21.00% in the 1st quarter of 2020. 
Updated performance information, including the Fund’s current NAV, may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free). 
Performance Table Heading rr_PerformanceTableHeading Average Annual Total Returns (for the periods ended December 31, 2020)
Performance Table Uses Highest Federal Rate rr_PerformanceTableUsesHighestFederalRate After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred rr_PerformanceTableNotRelevantToTaxDeferred Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”).
Performance Table Explanation after Tax Higher rr_PerformanceTableExplanationAfterTaxHigher Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.
iShares Morningstar Multi-Asset Income ETF | iShares Morningstar Multi-Asset Income ETF  
Risk/Return: rr_RiskReturnAbstract  
Management Fees rr_ManagementFeesOverAssets 0.25%
Distribution and Service (12b-1) Fees rr_DistributionAndService12b1FeesOverAssets none
Other Expenses rr_OtherExpensesOverAssets none [1]
Acquired Fund Fees and Expenses rr_AcquiredFundFeesAndExpensesOverAssets 0.35%
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.60%
Fee Waiver rr_FeeWaiverOrReimbursementOverAssets (0.01%)
Total Annual Fund Operating Expenses After Fee Waiver rr_NetExpensesOverAssets 0.59%
1 Year rr_ExpenseExampleYear01 $ 60
3 Years rr_ExpenseExampleYear03 189
5 Years rr_ExpenseExampleYear05 329
10 Years rr_ExpenseExampleYear10 $ 745
2013 rr_AnnualReturn2013 0.57%
2014 rr_AnnualReturn2014 10.15%
2015 rr_AnnualReturn2015 (4.77%)
2016 rr_AnnualReturn2016 9.79%
2017 rr_AnnualReturn2017 10.87%
2018 rr_AnnualReturn2018 (4.75%)
2019 rr_AnnualReturn2019 15.88%
2020 rr_AnnualReturn2020 (1.25%) [2]
Year to Date Return, Label rr_YearToDateReturnLabel The Fund’s year-to-date return
Bar Chart, Year to Date Return, Date rr_BarChartYearToDateReturnDate Sep. 30, 2021
Bar Chart, Year to Date Return rr_BarChartYearToDateReturn 1.70%
Highest Quarterly Return, Label rr_HighestQuarterlyReturnLabel best
Highest Quarterly Return, Date rr_BarChartHighestQuarterlyReturnDate Jun. 30, 2020
Highest Quarterly Return rr_BarChartHighestQuarterlyReturn 12.54%
Lowest Quarterly Return, Label rr_LowestQuarterlyReturnLabel worst
Lowest Quarterly Return, Date rr_BarChartLowestQuarterlyReturnDate Mar. 31, 2020
Lowest Quarterly Return rr_BarChartLowestQuarterlyReturn (21.00%)
One Year rr_AverageAnnualReturnYear01 (1.25%)
Five Years rr_AverageAnnualReturnYear05 5.82%
Since Fund Inception rr_AverageAnnualReturnSinceInception 4.92%
Inception Date rr_AverageAnnualReturnInceptionDate Apr. 03, 2012
iShares Morningstar Multi-Asset Income ETF | Return After Taxes on Distributions | iShares Morningstar Multi-Asset Income ETF  
Risk/Return: rr_RiskReturnAbstract  
One Year rr_AverageAnnualReturnYear01 (2.80%) [3]
Five Years rr_AverageAnnualReturnYear05 4.00% [3]
Since Fund Inception rr_AverageAnnualReturnSinceInception 2.95% [3]
iShares Morningstar Multi-Asset Income ETF | Return After Taxes on Distributions and Sale of Fund Shares | iShares Morningstar Multi-Asset Income ETF  
Risk/Return: rr_RiskReturnAbstract  
One Year rr_AverageAnnualReturnYear01 (0.60%) [3]
Five Years rr_AverageAnnualReturnYear05 3.81% [3]
Since Fund Inception rr_AverageAnnualReturnSinceInception 3.03% [3]
iShares Morningstar Multi-Asset Income ETF | Morningstar Multi-Asset High Income Index (Index returns do not reflect deductions for fees, expenses, or taxes)  
Risk/Return: rr_RiskReturnAbstract  
One Year rr_AverageAnnualReturnYear01 (0.92%)
Five Years rr_AverageAnnualReturnYear05 5.94%
Since Fund Inception rr_AverageAnnualReturnSinceInception 4.97%
[1] The amount rounded to 0.00%.
[2] The Fund’s year-to-date return as of September 30, 2021 was 1.70%. 
[3] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.