Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	iSHARES TRUST
Prospectus Date	rr_ProspectusDate	Jun. 29, 2018
iShares ESG USD Corporate Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	iSHARES^® ESG USD CORPORATE BOND ETF Ticker: SUSC Stock Exchange: NASDAQ
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The iShares ESG USD Corporate Bond ETF (the “Fund”) seeks to track the investment results of an index composed of U.S. dollar-denominated, investment-grade corporate bonds issued by companies that have positive environmental, social and governance characteristics while exhibiting risk and return characteristics similar to those of the parent index of such index.
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 own 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. You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (ongoing expenses that you pay each year as a percentage of the value of your investments)
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover.
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund may pay 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 Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. From inception (July 11, 2017) to the most recent fiscal year end, the Fund's portfolio turnover rate was 17% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	17.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
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 seeks to track the investment results of the Bloomberg Barclays MSCI US Corporate ESG Focus Index (the “Underlying Index”), which has been developed by Bloomberg Barclays Capital Inc. (the “Index Provider” or “Bloomberg Barclays”) with environmental, social and governance (“ESG”) rating inputs from MSCI ESG Research LLC (“MSCI ESG Research”) pursuant to an agreement between MSCI ESG Research and Bloomberg Index Services Limited, a subsidiary of Bloomberg Barclays. The Underlying Index is an optimized fixed-income index designed to reflect the performance of U.S. dollar-denominated, investment-grade (as determined by Bloomberg Barclays) corporate bonds issued by companies that have positive ESG characteristics (as determined by MSCI ESG Research ratings), while exhibiting risk and return characteristics similar to those of the Bloomberg Barclays US Corporate Index (the “Parent Index”). As of February 28, 2018, the Underlying Index included issuers from the following countries: Australia, Belgium, Bermuda, Brazil, Canada, Chile, China, Colombia, France, Germany, Ireland, Italy, Japan, Mexico, the Netherlands, Singapore, South Korea, Spain, Sweden, Switzerland, the United Kingdom (the “U.K.”), and the U.S. The Index Provider begins with the Parent Index, excludes companies involved in the business of tobacco, companies involved with controversial weapons, producers and retailers of civilian firearms, as well as companies involved in very severe business controversies (in each case as determined by MSCI ESG Research), and then follows a quantitative process in an effort to determine optimal weights for securities to maximize exposure to securities of companies with higher ESG ratings, subject to maintaining risk and return characteristics similar to the Parent Index. For each industry, MSCI ESG Research identifies key ESG issues that can lead to substantial costs or opportunities for companies (e.g., climate change, resource scarcity, demographic shifts). MSCI ESG Research then rates each company’s exposure to each key issue based on the company’s business segment and geographic risk and analyzes the extent to which companies have developed robust strategies and programs to manage ESG risks and opportunities. MSCI ESG Research scores companies based on both their risk exposure and risk management. To score well on a key issue, MSCI ESG Research assesses management practices, management performance (through demonstrated track record and other quantitative performance indicators), governance structures, and/or implications in controversies, which all may be taken as a proxy for overall management quality. Controversies, including, among other things, issues involving anti-competitive practices, toxic emissions and waste, and health and safety, occurring within the last three years lead to a deduction from the overall management score on each issue. Using a sector-specific key issue weighting model, companies are rated and ranked in comparison to their industry peers. Key issues and weights are reviewed at the end of each calendar year. Corporate governance is always weighted and analyzed for all companies. As of February 28, 2018, there were 2,169 issues in the Underlying Index. As of February 28, 2018, a significant portion of the Underlying Index is represented by securities of companies in the financials and industrials industries or sectors. The components of the Underlying Index, and the degree to which these components represent certain industries or sectors, are likely to change over time. The Underlying Index consists of U.S. dollar-denominated corporate bonds that are investment-grade, fixed-rate and taxable and have remaining maturities of greater than or equal to one year. As of February 28, 2018, the average maturity of the securities in the Underlying Index was 7.15 years and the average credit rating was BBB+. The securities in the Underlying Index are updated on the last business day of each month. 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 keeping 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, duration, maturity, credit ratings and yield) and liquidity measures similar to those of an applicable underlying index. The Fund may or may not hold all of the securities in the Underlying Index. The Fund generally will invest at least 90% of its assets in the component securities of the Underlying Index and may invest up to 10% 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 (“BlackRock Cash Funds”), as well as in securities not included in the Underlying Index, but which BFA believes will help the Fund track the Underlying Index. From time to time when conditions warrant, the Fund may invest at least 80% of its assets in the component 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 BlackRock Cash Funds, as well as in securities not included in the Underlying Index, but which BFA believes will help the Fund track 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 Bloomberg Barclays, MSCI ESG Research or their affiliates, which are 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), repurchase agreements collateralized by U.S. government securities, and securities of state or municipal governments and their political subdivisions 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), repurchase agreements collateralized by U.S. government securities, and securities of state or municipal governments and their political subdivisions 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, 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. Asset Class Risk. Securities and other assets in the Underlying Index or in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes. Securities of companies that have positive or favorable ESG characteristics may underperform other securities. Assets Under Management (AUM) Risk. From time to time, an Authorized Participant (as defined in the Creations and Redemptions section of this prospectus (the “Prospectus”)), a third-party investor, the Fund’s adviser or an affiliate of the Fund’s adviser, or a fund may invest in the Fund and hold its investment for a specific period of time in order to facilitate commencement of the Fund’s operations or to allow the Fund to achieve size or scale. There can be no assurance that any such entity would not redeem its investment or that the size of the Fund would be maintained at such levels, which could negatively impact the Fund. Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. 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 Creation Units (as defined in the Purchase and Sale of Fund Shares section of the Prospectus), 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 exchange-traded funds (“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. Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund may “call” or repay the security before its stated maturity, and the 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 investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. Consumer Staples Sector Risk. The consumer staples sector may be affected by, among other things, marketing campaigns, changes in consumer demands, government regulations and changes in commodity prices. 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 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. Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers, market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting 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 cyber security plans and systems of the Fund’s service providers, the Index Provider, market makers, Authorized Participants or issuers of securities in which the Fund invests. ESG Investment Strategy Risk. The Fund’s ESG investment strategy limits the types and number of investment opportunities available to the Fund and, as a result, the Fund may underperform other funds that do not have an ESG focus. The Fund’s ESG investment strategy may result in the Fund investing in securities or industry sectors that underperform the market as a whole or underperform other funds screened for ESG standards. In addition, the Index Provider may be unsuccessful in creating an index composed of companies that exhibit positive or favorable ESG characteristics. Extension Risk. During periods of rising interest rates, certain debt obligations may be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in the Fund’s income and potentially in the value of the Fund’s investments. 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 the 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, cyber attacks 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 the Fund. Income Risk. The Fund's income may decline when interest rates fall. This decline can occur because the 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 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. Industrials Sector Risk. Companies in the industrials sector may be adversely affected by changes in the supply of and demand for products and services, product obsolescence and changes in general economic conditions, among other factors. While the Fund seeks to invest in companies with positive or favorable environmental and social characteristics, companies in the industrials sector may also be adversely affected by claims for environmental damage or product liability. Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. Issuer Risk. The performance of the Fund depends on the performance of individual securities to which the Fund has exposure. Changes in the financial condition or credit rating of an issuer of those securities may cause the value of the securities to decline. Liquidity Risk. Liquidity risk exists when particular investments are difficult to purchase or sell. This can reduce the Fund's returns because the Fund may be unable to transact at advantageous times or prices. Management Risk. As the Fund may 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 could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund 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 SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. Non-Diversification Risk. The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers. As a result, the Fund's performance may depend on the performance of a small number of issuers. Non-U.S. Issuers Risk. Securities issued by non-U.S. issuers carry different risks from securities issued by U.S. issuers. These risks include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or confiscatory taxation, adverse changes in investment or exchange control regulations, political instability, regulatory and economic differences, and potential restrictions on the flow of international capital. Operational Risk. The Fund is 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 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 is not actively managed, and BFA generally does not attempt to take defensive positions under any market conditions, including declining markets. Risk of Investing in Developed Countries. The Fund’s investment in developed country issuers may subject the Fund to regulatory, political, currency, security, economic and other risks associated with developed countries. Developed countries tend to represent a significant portion of the global economy and have generally experienced slower economic growth than some less developed countries. Certain developed countries have experienced security concerns, such as terrorism and strained international relations. Incidents involving a country’s or region’s security may cause uncertainty in its markets and may adversely affect its economy and the Fund’s investments. In addition, developed countries may be adversely impacted by changes to the economic conditions of certain key trading partners, regulatory burdens, debt burdens and the price or availability of certain commodities. Risk of Investing in the United States. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure. Securities Lending Risk. The Fund may engage in securities lending. Securities lending involves the risk that the Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund 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. Small Fund Risk. When the Fund’s size is small, the Fund may experience low trading volume and wide bid/ask spreads. In addition, the Fund may face the risk of being delisted if the Fund does not meet certain conditions of the listing exchange. If the Fund were to be required to delist from the listing exchange, the value of the Fund may rapidly decline and performance may be negatively impacted. In addition, any resulting liquidation could cause the Fund to incur elevated transaction costs for the Fund and negative tax consequences for investors. Tracking Error Risk. The Fund 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), differences in transaction costs, the Fund’s holding of uninvested cash, differences in timing of the accrual of or the valuation of distributions, tax gains or losses, changes to the Underlying Index or the costs to the 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 incurs fees and expenses, while the Underlying Index does not. BFA EXPECTS THAT THE FUND MAY EXPERIENCE HIGHER TRACKING ERROR THAN IS TYPICAL FOR SIMILAR INDEX ETFs.
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.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	Non-Diversification Risk. The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers. As a result, the Fund's performance may depend on the performance of a small number of issuers.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance Information
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	As of the date of the Prospectus, the Fund has been in operation for less than one full calendar year and therefore does not report its performance information.
Performance One Year or Less [Text]	rr_PerformanceOneYearOrLess	As of the date of the Prospectus, the Fund has been in operation for less than one full calendar year and therefore does not report its performance information.
iShares ESG USD Corporate Bond ETF \| iShares ESG USD Corporate Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.18%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	none
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.18%
1 Year	rr_ExpenseExampleYear01	$ 18
3 Years	rr_ExpenseExampleYear03	58
5 Years	rr_ExpenseExampleYear05	101
10 Years	rr_ExpenseExampleYear10	$ 230

Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

iSHARES TRUST

Prospectus Date

rr_ProspectusDate

Jun. 29, 2018

iShares ESG USD Corporate Bond ETF

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

iSHARES^® ESG USD CORPORATE BOND ETF
Ticker: SUSC Stock Exchange: NASDAQ

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

The iShares ESG USD Corporate Bond ETF (the “Fund”) seeks to track the investment results of an index composed of U.S. dollar-denominated, investment-grade corporate bonds issued by companies that have positive environmental, social and governance characteristics while exhibiting risk and return characteristics similar to those of the parent index of such index.

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 own 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.

You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

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

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover.

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund may pay 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 Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. From inception (July 11, 2017) to the most recent fiscal year end, the Fund's portfolio turnover rate was 17% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

17.00%

Expense Exchange Traded Fund Commissions [Text]

rr_ExpenseExchangeTradedFundCommissions

You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:

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 seeks to track the investment results of the Bloomberg Barclays MSCI US Corporate ESG Focus Index (the “Underlying Index”), which has been developed by Bloomberg Barclays Capital Inc. (the “Index Provider” or “Bloomberg Barclays”) with environmental, social and governance (“ESG”) rating inputs from MSCI ESG Research LLC (“MSCI ESG Research”) pursuant to an agreement between MSCI ESG Research and Bloomberg Index Services Limited, a subsidiary of Bloomberg Barclays. The Underlying Index is an optimized fixed-income index designed to reflect the performance of U.S. dollar-denominated, investment-grade (as determined by Bloomberg Barclays) corporate bonds issued by companies that have positive ESG characteristics (as determined by MSCI ESG Research ratings), while exhibiting risk and return characteristics similar to those of the Bloomberg Barclays US Corporate Index (the “Parent Index”). As of February 28, 2018, the Underlying Index included issuers from the following countries: Australia, Belgium, Bermuda, Brazil, Canada, Chile, China, Colombia, France, Germany, Ireland, Italy, Japan, Mexico, the Netherlands, Singapore, South Korea, Spain, Sweden, Switzerland, the United Kingdom (the “U.K.”), and the U.S.

The Index Provider begins with the Parent Index, excludes companies involved in the business of tobacco, companies involved with controversial weapons, producers and retailers of civilian firearms, as well as companies involved in very severe business controversies (in each case as determined by MSCI ESG Research), and then follows a quantitative process in an effort to determine optimal weights for securities to maximize exposure to securities of companies with higher ESG ratings, subject to maintaining risk and return characteristics similar to the Parent Index.

For each industry, MSCI ESG Research identifies key ESG issues that can lead to substantial costs or opportunities for companies (e.g., climate change, resource scarcity, demographic shifts). MSCI ESG Research then rates each company’s exposure to each key issue based on the company’s business segment and geographic risk and analyzes the extent to which companies have developed robust strategies and programs to manage ESG risks and opportunities. MSCI ESG Research scores companies based on both their risk exposure and risk management. To score well on a key issue, MSCI ESG Research assesses management practices, management performance (through demonstrated track record and other quantitative performance indicators), governance structures, and/or implications in controversies, which all may be taken as a proxy for overall management quality. Controversies, including, among other things, issues involving anti-competitive practices, toxic emissions and waste, and health and safety, occurring within the last three years lead to a deduction from the overall management score on each issue. Using a sector-specific key issue weighting model, companies are rated and ranked in comparison to their industry peers. Key issues and weights are reviewed at the end of each calendar year. Corporate governance is always weighted and analyzed for all companies.

As of February 28, 2018, there were 2,169 issues in the Underlying Index. As of February 28, 2018, a significant portion of the Underlying Index is represented by securities of companies in the financials and industrials industries or sectors. The components of the Underlying Index, and the degree to which these components represent certain industries or sectors, are likely to change over time.

The Underlying Index consists of U.S. dollar-denominated corporate bonds that are investment-grade, fixed-rate and taxable and have remaining maturities of greater than or equal to one year. As of February 28, 2018, the average maturity of the securities in the Underlying Index was 7.15 years and the average credit rating was BBB+. The securities in the Underlying Index are updated on the last business day of each month.

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 keeping 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, duration, maturity, credit ratings and yield) and liquidity measures similar to those of an applicable underlying index. The Fund may or may not hold all of the securities in the Underlying Index.

The Fund generally will invest at least 90% of its assets in the component securities of the Underlying Index and may invest up to 10% 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 (“BlackRock Cash Funds”), as well as in securities not included in the Underlying Index, but which BFA believes will help the Fund track the Underlying Index. From time to time when conditions warrant, the Fund may invest at least 80% of its assets in the component 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 BlackRock Cash Funds, as well as in securities not included in the Underlying Index, but which BFA believes will help the Fund track 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 Bloomberg Barclays, MSCI ESG Research or their affiliates, which are 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), repurchase agreements collateralized by U.S. government securities, and securities of state or municipal governments and their political subdivisions 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), repurchase agreements collateralized by U.S. government securities, and securities of state or municipal governments and their political subdivisions are not considered to be issued by members of any industry.

Risk [Heading]

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Summary of Principal Risks

Risk Narrative [Text Block]

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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, 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.

Asset Class Risk. Securities and other assets in the Underlying Index or in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes. Securities of companies that have positive or favorable ESG characteristics may underperform other securities.

Assets Under Management (AUM) Risk. From time to time, an Authorized Participant (as defined in the Creations and Redemptions section of this prospectus (the “Prospectus”)), a third-party investor, the Fund’s adviser or an affiliate of the Fund’s adviser, or a fund may invest in the Fund and hold its investment for a specific period of time in order to facilitate commencement of the Fund’s operations or to allow the Fund to achieve size or scale. There can be no assurance that any such entity would not redeem its investment or that the size of the Fund would be maintained at such levels, which could negatively impact the Fund.

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. 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 Creation Units (as defined in the Purchase and Sale of Fund Shares section of the Prospectus), 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 exchange-traded funds (“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.

Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund may “call” or repay the security before its stated maturity, and the 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 investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class.

Consumer Staples Sector Risk. The consumer staples sector may be affected by, among other things, marketing campaigns, changes in consumer demands, government regulations and changes in commodity prices.

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 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.

Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers, market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting 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 cyber security plans and systems of the Fund’s service providers, the Index Provider, market makers, Authorized Participants or issuers of securities in which the Fund invests.

ESG Investment Strategy Risk. The Fund’s ESG investment strategy limits the types and number of investment opportunities available to the Fund and, as a result, the Fund may underperform other funds that do not have an ESG focus. The Fund’s ESG investment strategy may result in the Fund investing in securities or industry sectors that underperform the market as a whole or underperform other funds screened for ESG standards. In addition, the Index Provider may be unsuccessful in creating an index composed of companies that exhibit positive or favorable ESG characteristics.

Extension Risk. During periods of rising interest rates, certain debt obligations may be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in the Fund’s income and potentially in the value of the Fund’s investments.

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 the 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, cyber attacks 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 the Fund.

Income Risk. The Fund's income may decline when interest rates fall. This decline can occur because the 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 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.

Industrials Sector Risk. Companies in the industrials sector may be adversely affected by changes in the supply of and demand for products and services, product obsolescence and changes in general economic conditions, among other factors. While the Fund seeks to invest in companies with positive or favorable environmental and social characteristics, companies in the industrials sector may also be adversely affected by claims for environmental damage or product liability.

Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates.

Issuer Risk. The performance of the Fund depends on the performance of individual securities to which the Fund has exposure. Changes in the financial condition or credit rating of an issuer of those securities may cause the value of the securities to decline.

Liquidity Risk. Liquidity risk exists when particular investments are difficult to purchase or sell. This can reduce the Fund's returns because the Fund may be unable to transact at advantageous times or prices.

Management Risk. As the Fund may 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 could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns.

Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund 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 SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

Non-Diversification Risk. The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers. As a result, the Fund's performance may depend on the performance of a small number of issuers.

Non-U.S. Issuers Risk. Securities issued by non-U.S. issuers carry different risks from securities issued by U.S. issuers. These risks include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or confiscatory taxation, adverse changes in investment or exchange control regulations, political instability, regulatory and economic differences, and potential restrictions on the flow of international capital.

Operational Risk. The Fund is 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 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 is not actively managed, and BFA generally does not attempt to take defensive positions under any market conditions, including declining markets.

Risk of Investing in Developed Countries. The Fund’s investment in developed country issuers may subject the Fund to regulatory, political, currency, security, economic and other risks associated with developed countries. Developed countries tend to represent a significant portion of the global economy and have generally experienced slower economic growth than some less developed countries. Certain developed countries have experienced security concerns, such as terrorism and strained international relations. Incidents involving a country’s or region’s security may cause uncertainty in its markets and may adversely affect its economy and the Fund’s investments. In addition, developed countries may be adversely impacted by changes to the economic conditions of certain key trading partners, regulatory burdens, debt burdens and the price or availability of certain commodities.

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

Securities Lending Risk. The Fund may engage in securities lending. Securities lending involves the risk that the Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund 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.

Small Fund Risk. When the Fund’s size is small, the Fund may experience low trading volume and wide bid/ask spreads. In addition, the Fund may face the risk of being delisted if the Fund does not meet certain conditions of the listing exchange. If the Fund were to be required to delist from the listing exchange, the value of the Fund may rapidly decline and performance may be negatively impacted. In addition, any resulting liquidation could cause the Fund to incur elevated transaction costs for the Fund and negative tax consequences for investors.

Tracking Error Risk. The Fund 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), differences in transaction costs, the Fund’s holding of uninvested cash, differences in timing of the accrual of or the valuation of distributions, tax gains or losses, changes to the Underlying Index or the costs to the 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 incurs fees and expenses, while the Underlying Index does not. BFA EXPECTS THAT THE FUND MAY EXPERIENCE HIGHER TRACKING ERROR THAN IS TYPICAL FOR SIMILAR INDEX ETFs.

Risk Lose Money [Text]

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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.

Risk Nondiversified Status [Text]

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Non-Diversification Risk. The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers. As a result, the Fund's performance may depend on the performance of a small number of issuers.

Bar Chart and Performance Table [Heading]

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Performance Information

Performance Narrative [Text Block]

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As of the date of the Prospectus, the Fund has been in operation for less than one full calendar year and therefore does not report its performance information.

Performance One Year or Less [Text]

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As of the date of the Prospectus, the Fund has been in operation for less than one full calendar year and therefore does not report its performance information.

iShares ESG USD Corporate Bond ETF | iShares ESG USD Corporate Bond ETF

Risk/Return:

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Management Fees

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0.18%

Distribution and Service (12b-1) Fees

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none

Other Expenses

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none