Investment Strategy |
Feb. 28, 2026 |
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| iShares 1-5 Year Investment Grade Corporate Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® BofA® 1-5 Year US Corporate Index (the “Underlying Index”), which measures the performance of investment-grade corporate bonds of both U.S. and non-U.S. issuers that are U.S. dollar-denominated, publicly issued in the U.S. domestic market or certain issuances pursuant to Rule 144A under the Securities Act of 1933, as amended, (the “1933 Act”) with or without registration rights, and have a remaining maturity of greater than or equal to one year and less than five years. As of February 28, 2026, there were 4,553 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by securities of companies in the financials industry or sector. The components of the Underlying Index are likely to change over time. The Underlying Index consists of investment-grade corporate bonds that have $250 million or more of outstanding face value. The Index Provider deems securities as “investment grade” based on the average rating of Fitch Ratings, Inc. (BBB or better), Moody’s Investors Service, Inc. (Baa or better) and/or Standard & Poor's® Financial Services LLC, a subsidiary of S&P Global (BBB or better). In addition, the securities in the Underlying Index must be denominated in U.S. dollars and must be fixed-rate. Excluded from the Underlying Index are equity-linked securities, securities in legal default, hybrid securitized corporate bonds, Eurodollar bonds (U.S. dollar-denominated securities not issued in the U.S. domestic market), taxable and tax-exempt U.S. municipal securities and dividends-received-deduction-eligible securities. The Underlying Index is market capitalization-weighted, and the securities in the Underlying Index are updated on the last calendar day of each month. Weighted average maturity is a U.S. dollar-weighted average of the remaining term to maturity of the underlying securities in the Fund’s portfolio. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares 5-10 Year Investment Grade Corporate Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® BofA® 5-10 Year US Corporate Index (the “Underlying Index”), which measures the performance of investment-grade corporate bonds of both U.S. and non-U.S. issuers that are U.S. dollar-denominated, publicly issued in the U.S. domestic market or certain issuances pursuant to Rule 144A under the Securities Act of 1933, as amended, (the “1933 Act”) with or without registration rights, and have a remaining maturity of greater than or equal to five years and less than ten years. As of February 28, 2026, there were 2,982 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by securities of companies in the financials industry or sector. The components of the Underlying Index are likely to change over time. The Underlying Index consists of investment-grade corporate bonds that have $250 million or more of outstanding face value. The Index Provider deems securities as “investment grade” based on the average rating of Fitch Ratings, Inc. (BBB or better), Moody’s Investors Service, Inc. (Baa or better) and/or Standard & Poor's® Financial Services LLC, a subsidiary of S&P Global (BBB or better). In addition, the securities in the Underlying Index must be denominated in U.S. dollars and must be fixed-rate. Excluded from the Underlying Index are equity-linked securities, securities in legal default, hybrid securitized corporate bonds, Eurodollar bonds (U.S. dollar-denominated securities not issued in the U.S. domestic market), taxable and tax-exempt U.S. municipal securities and dividends-received-deduction-eligible securities. The Underlying Index is market capitalization-weighted, and the securities in the Underlying Index are updated on the last calendar day of each month. Weighted average maturity is a U.S. dollar-weighted average of the remaining term to maturity of the underlying securities in the Fund’s portfolio. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares 10+ Year Investment Grade Corporate Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® BofA® 10+ Year US Corporate Index (the “Underlying Index”), which measures the performance of investment-grade corporate bonds of both U.S. and non-U.S. issuers that are U.S. dollar-denominated, publicly issued in the U.S. domestic market or certain issuances pursuant to Rule 144A under the Securities Act of 1933, as amended, (the “1933 Act”) with or without registration rights, and have a remaining maturity of greater than or equal to ten years. As of February 28, 2026, there were 3,859 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by securities of companies in the financials industry or sector. The components of the Underlying Index are likely to change over time. The Underlying Index consists of investment-grade corporate bonds that have $250 million or more of outstanding face value. The Index Provider deems securities as “investment grade” based on the average rating of Fitch Ratings, Inc. (BBB or better), Moody’s Investors Service, Inc. (Baa or better) and/or Standard & Poor's® Financial Services LLC, a subsidiary of S&P Global (BBB or better). In addition, the securities in the Underlying Index must be denominated in U.S. dollars and must be fixed-rate. Excluded from the Underlying Index are equity-linked securities, securities in legal default, hybrid securitized corporate bonds, Eurodollar bonds (U.S. dollar-denominated securities not issued in the U.S. domestic market), taxable and tax-exempt U.S. municipal securities and dividends-received-deduction-eligible securities. The Underlying Index is market capitalization-weighted, and the securities in the Underlying Index are updated on the last calendar day of each month. Weighted average maturity is a U.S. dollar-weighted average of the remaining term to maturity of the underlying securities in the Fund's portfolio. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares BBB Rated Corporate Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the iBoxx® USD Liquid Investment Grade BBB 0+ Index (the “Underlying Index”), which is designed to reflect the performance of BBB (or its equivalent) fixed rate U.S. dollar-denominated bonds issued by U.S. and non-U.S. corporate issuers (as determined by S&P Dow Jones Indices LLC (the “Index Provider” or “SPDJI”)). Securities of varying maturities are eligible for inclusion in the Underlying Index. The Underlying Index offers exposure to liquid (according to SPDJI’s liquidity screens, which could vary from other measures of liquidity) investment-grade corporate bonds and is rebalanced on a monthly basis. Bonds in the Underlying Index are selected from the universe of eligible bonds using defined rules. The bonds eligible for inclusion are fixed rate U.S. dollar-denominated corporate bonds that: (i) are issued by issuers domiciled in the countries classified as developed markets by the Index Provider; (ii) are rated BBB or its equivalent by Fitch Ratings, Inc., Moody’s Investor’s Service, Inc. or Standard & Poor’s® Global Ratings, a subsidiary of S&P Global; (iii) are issued by issuers of debt securities with at least $1 billion aggregate outstanding face value; (iv) have at least $500 million of outstanding face value; (v) have a time to maturity of at least one year at issuance; and (vi) for new index insertions, have at least six months to maturity. Existing bonds in the Underlying Index are held to maturity so long as they meet all criteria other than the six months to maturity criterion. Bonds in the Underlying Index that no longer satisfy all the criteria (except the six months to maturity criterion) at month-end will be removed from the Underlying Index. A bond that drops out of the Underlying Index at the rebalancing day is excluded from reentering the index for a three-month period. The rule for the lockout period takes precedence over the other rules for the Underlying Index selection. A locked out bond will not be selected, even if it qualifies for the index. If a bond becomes eligible in the middle of the month, it will still need to satisfy the criteria at the end of the month, and can be included only upon rebalancing at month-end. Any bond that enters the Underlying Index must remain in the Underlying Index for a minimum of six months provided it is not downgraded to sub-investment grade, defaulted or fully redeemed in that period. Existing bonds in the Underlying Index that receive a rating upgrade can remain in the index if the six-month minimum has not been satisfied. The Underlying Index uses a modified market-value weighted methodology with a cap on each issuer of 3%. As of February 28, 2026, there were 3,195 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by securities of companies in the consumer goods and services and financials industries or sectors. The components of the Underlying Index are likely to change over time. The Fund may invest in privately-issued securities, including those that are normally purchased pursuant to Rule 144A or Regulation S promulgated under the Securities Act of 1933, as amended (the “1933 Act”). BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund invests at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 SPDJI, which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund invests at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares Broad USD Investment Grade Corporate Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® BofA® US Corporate Index (the “Underlying Index”), which measures the performance of investment-grade corporate bonds of both U.S. and non-U.S. issuers that are U.S. dollar-denominated, publicly issued in the U.S. domestic market or certain issuances pursuant to Rule 144A under the Securities Act of 1933, as amended, (the “1933 Act”) with or without registration rights. As of February 28, 2026, there were 11,394 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by securities of companies in the financials industry or sector. The components of the Underlying Index are likely to change over time. The Underlying Index consists of investment-grade corporate bonds that have $250 million or more of outstanding face value. As of February 28, 2026, the Underlying Index included issuers from the following countries: Argentina, Australia, Austria, Barbados, Belgium, Bermuda, Brazil, Canada, Chile, China, Colombia, Czech Republic, Denmark, Finland, France, Germany, Hong Kong, India, Indonesia, Ireland, Israel, Italy, Japan, Kazakhstan, Kuwait, Luxembourg, Macau, Malaysia, Mexico, Morocco, the Netherlands, New Zealand, Norway, Oman, Panama, Peru, Poland, Portugal, Puerto Rico, Qatar, Saudi Arabia, Singapore, South Africa, South Korea, Spain, Sweden, Switzerland, Taiwan, Thailand, Turkey, the United Arab Emirates, the U.K. and the U.S. The Index Provider deems securities as “investment grade” based on the average rating of Fitch Ratings, Inc. (BBB or better), Moody’s Investors Service, Inc. (Baa or better) and/or Standard & Poor's® Financial Services LLC, a subsidiary of S&P Global (BBB or better). In addition, the securities in the Underlying Index must be denominated in U.S. dollars and must be fixed-rate. Excluded from the Underlying Index are equity-linked securities, securities in legal default, hybrid securitized corporate bonds, Eurodollar bonds (U.S. dollar-denominated securities not issued in the U.S. domestic market), taxable and tax-exempt U.S. municipal securities and dividends-received-deduction-eligible securities. The Underlying Index is market capitalization-weighted, and the securities in the Underlying Index are updated on the last calendar day of each month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares ESG Aware 1-5 Year USD Corporate Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the Bloomberg MSCI US Corporate 1-5 Year ESG Focus Index (the “Underlying Index”), which has been developed by Bloomberg Finance L.P. and its affiliates (the “Index Provider” or “Bloomberg”) with environmental, social and governance (“ESG”) rating inputs from MSCI Solutions LLC (“MSCI Solutions”) pursuant to an agreement between MSCI Solutions and Bloomberg Index Services Limited, a subsidiary of Bloomberg. 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) corporate bonds having remaining maturities between one and five years and issued by companies that have positive ESG characteristics (as determined by MSCI Solutions ratings), while seeking to exhibit risk and return characteristics similar to those of the Bloomberg US Corporate 1-5 Years Index (the “Parent Index”). As of February 28, 2026, the Underlying Index included issuers from Australia, Belgium, Bermuda, Brazil, Canada, Chile, China, Finland, France, Germany, Hong Kong, Ireland, Italy, Japan, Macau, Mexico, the Netherlands, Spain, Sweden, Switzerland, Taiwan, the United Kingdom (the “U.K.) and the U.S. The Index Provider begins with the Parent Index and excludes companies involved in the business of tobacco, companies involved with controversial weapons, producers and retailers of civilian firearms, companies involved in certain fossil fuels-related activity (such as the production of thermal coal, thermal coal-based power generation and extraction of oil sands) based on revenue or percentage of revenue thresholds for certain categories (e.g., $20 million or 5%) and categorical exclusions for others (e.g., controversial weapons). The Index Provider also excludes companies involved in very severe business controversies (in each case as determined by MSCI Solutions), as well as securities of companies without an MSCI Solutions rating, 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 and require a minimum ESG score improvement of 10% or greater relative to the Parent Index. For each industry, MSCI Solutions identifies key ESG issues that can lead to substantial costs or opportunities for companies (e.g., climate change, resource scarcity, demographic shifts). MSCI Solutions 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 Solutions scores companies based on both their risk exposure and risk management. To score well on a key issue, MSCI Solutions 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, 2026, there were 1,768 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by securities of companies in the consumer goods and services and financials industries or sectors. The components of the Underlying Index 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 effective maturities between one and five years. The securities in the Underlying Index are updated on the last business day of each month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options, and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 Bloomberg, MSCI Solutions or their affiliates, which are independent of the Fund and BFA, pursuant to an agreement between MSCI Solutions and Bloomberg Index Services Limited (a subsidiary of Bloomberg) or an affiliate. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares ESG Aware USD Corporate Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the Bloomberg MSCI US Corporate ESG Focus Index (the “Underlying Index”), which has been developed by Bloomberg Finance L.P. and its affiliates (the “Index Provider” or “Bloomberg”) with environmental, social and governance (“ESG”) rating inputs from MSCI Solutions LLC (“MSCI Solutions”) pursuant to an agreement between MSCI Solutions and Bloomberg Index Services Limited, a subsidiary of Bloomberg. 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) corporate bonds issued by companies that have positive ESG characteristics (as determined by MSCI Solutions ratings), while seeking to exhibit risk and return characteristics similar to those of the Bloomberg US Corporate Index (the “Parent Index”). As of February 28, 2026, the Underlying Index included issuers from Australia, Belgium, Bermuda, Brazil, Canada, Chile, China, Finland, France, Germany, Hong Kong, Ireland, Italy, Japan, Macau, Mexico, the Netherlands, Spain, Switzerland, Taiwan, the United Kingdom (the “U.K.”), and the U.S. The Index Provider begins with the Parent Index and excludes companies involved in the business of tobacco, companies involved with controversial weapons, producers and retailers of civilian firearms, companies involved in certain fossil fuels-related activity (such as the production of thermal coal, thermal coal-based power generation and extraction of oil sands) based on revenue or percentage of revenue thresholds for certain categories (e.g., $20 million or 5%) and categorical exclusions for others (e.g., controversial weapons). The Index Provider also excludes companies involved in very severe business controversies (in each case as determined by MSCI Solutions), as well as securities of companies without an MSCI Solutions rating, 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 and require a minimum ESG score improvement of 10% or greater relative to the Parent Index. For each industry, MSCI Solutions identifies key ESG issues that can lead to substantial costs or opportunities for companies (e.g., climate change, resource scarcity, demographic shifts). MSCI Solutions 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 Solutions scores companies based on both their risk exposure and risk management. To score well on a key issue, MSCI Solutions 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, 2026, there were 4,008 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by securities of companies in the consumer goods and services and financials industries or sectors. The components of the Underlying Index 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. The securities in the Underlying Index are updated on the last business day of each month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options, and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 Bloomberg, MSCI Solutions or their affiliates, which are independent of the Fund and BFA, pursuant to an agreement between MSCI Solutions and Bloomberg Index Services Limited (a subsidiary of Bloomberg) or an affiliate. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares High Yield Systematic Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the BlackRock High Yield Systematic Bond Index (the “Underlying Index”), which consists of U.S. dollar-denominated, high yield (as determined by BlackRock Index Services, LLC (the “Index Provider”)) corporate bonds. Component securities include publicly-issued debt of U.S. corporate issuers, U.S. dollar-denominated, publicly issued debt of non-U.S. corporate issuers, and bonds offered pursuant to Rule 144A under the Securities Act of 1933, as amended (the “1933 Act”) with or without registration rights. As of February 28, 2026, there were 254 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by securities of companies in the consumer goods and services, energy and financials industries or sectors. The components of the Underlying Index are likely to change over time. The securities in the Underlying Index must have $350 million or more current face amount outstanding, and have at least one year to final maturity, regardless of optionality, at time of rebalance. In addition, the securities in the Underlying Index must be denominated in U.S. dollars and have a fixed-rate, although they can carry a coupon that steps-up (i.e., or changes according to a predetermined schedule), and must be rated below investment-grade, which is below Baa3 by Moody’s Investors Service, Inc. (“Moody's”) or below BBB- by Standard & Poor's® Global Ratings, a subsidiary of S&P Global (“S&P Global Ratings”) or Fitch Ratings, Inc. (“Fitch”). Eligibility in the Underlying Index is determined by the middle of the three available ratings. When a rating from only two agencies is available, the lower rating is used. When a rating from only one agency is available, that rating is used to determine eligibility in the Underlying Index. The Underlying Index determines constituent weights based on a proprietary methodology which first aims to systematically screen out certain bonds with the highest probability of default (a measure of credit quality) and then optimizes to improve risk-adjusted returns by weighting more heavily to bonds with attractive default-adjusted spreads (a measure of value) while mitigating portfolio risks and limiting turnover. This methodology, unlike the methodologies used by traditional market-value-weighted bond indexes, selects a portion of the component bonds from the broader universe of high yield bonds based on application of analytics measuring the probability of default. The resulting grouping of bonds is referred to as “defensive,” by comparison to other groupings of high yield bonds, because those included in the Underlying Index possess specific characteristics that the index methodology identifies as reducing the risk of default. Key investment characteristics such as duration are constrained to be within a specified range of a broader market-value-weighted high yield bond universe. The Underlying Index is rebalanced on the last business day of each month to reflect changes in eligibility, credit quality and valuation. High yield bonds included in the Underlying Index, like all high yield debt, continue to be subject to a number of risks, including the risk of an issuer default and volatility of the market value of the bonds. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 the Index Provider, an affiliated person of the Fund and of BFA, the Fund's investment adviser. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares iBoxx $ High Yield Corporate Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the iBoxx® USD Liquid High Yield Index (the “Underlying Index”), which is a rules-based index consisting of U.S. dollar-denominated, high yield (as determined by S&P Dow Jones Indices LLC (the “Index Provider” or “SPDJI”)) corporate bonds for sale in the U.S. The Underlying Index is designed to provide a broad representation of the U.S. dollar-denominated liquid high yield corporate bond market. The Underlying Index is a modified market-value weighted index with a cap on each issuer of 3%. There is no limit to the number of issues in the Underlying Index. As of February 28, 2026, the Underlying Index included approximately 1,300 constituents. As of February 28, 2026, a significant portion of the Underlying Index was represented by securities of companies in the consumer goods and services industry or sector. The components of the Underlying Index are likely to change over time. Bonds in the Underlying Index are selected from the universe of eligible bonds in the iBoxx USD Corporate Bond Index using defined rules. As of the date of this prospectus (the “Prospectus”), the bonds eligible for inclusion in the Underlying Index include U.S. dollar-denominated high yield corporate bonds that: (i) are issued by companies domiciled in countries classified as developed markets by SPDJI; (ii) have an average rating of sub-investment grade (ratings from Fitch Ratings, Inc. (“Fitch”), Moody's Investors Service, Inc. (“Moody's”) or Standard & Poor's® Global Ratings, a subsidiary of S&P Global (“S&P Global Ratings”) are considered; if more than one agency provides a rating, the average rating is attached to the bond); (iii) are from issuers with at least $1 billion outstanding face value; (iv) have at least $400 million of outstanding face value; (v) have an original maturity date of less than 15 years; (vi) have at least one year to maturity; and (vii) have at least one year and 6 months to maturity for new index insertions. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 SPDJI, which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares iBoxx $ Investment Grade Corporate Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the iBoxx® USD Liquid Investment Grade Index (the “Underlying Index”), which is a rules-based index consisting of U.S. dollar-denominated, investment-grade (as determined by S&P Dow Jones Indices LLC (the “Index Provider” or “SPDJI”)) corporate bonds for sale in the U.S. The Underlying Index is designed to provide a broad representation of the U.S. dollar-denominated liquid investment-grade corporate bond market. The Underlying Index is a modified market-value weighted index with a cap on each issuer of 3%. There is no limit to the number of issues in the Underlying Index. As of February 28, 2026, the Underlying Index included approximately 3,039 constituents. As of February 28, 2026, a significant portion of the Underlying Index was represented by securities of companies in the consumer goods and services and financials industries or sectors. The components of the Underlying Index are likely to change over time. The Underlying Index is a subset of the iBoxx USD Corporate Bond Index, which as of February 28, 2026, included 8,827 investment-grade bonds. Bonds in the Underlying Index are selected from the universe of eligible bonds in the iBoxx USD Corporate Bond Index using defined rules. As of the date of this prospectus (the “Prospectus”), the bonds eligible for inclusion in the Underlying Index consist of U.S. dollar-denominated corporate bonds that: (i) are issued by companies domiciled in countries classified as developed markets by SPDJI; (ii) have an average rating of investment grade (ratings from Fitch Ratings, Inc., Moody's Investors Service, Inc. or Standard & Poor's® Global Ratings, a subsidiary of S&P Global (“S&P Global Ratings”) are considered; if more than one agency provides a rating, the average rating is attached to the bond); (iii) are from issuers with at least $2 billion outstanding face value; (iv) have at least $750 million of outstanding face value; (v) have at least three years to maturity; and (vi) have at least three years and 6 months to maturity for new index insertions. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 SPDJI, which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares Investment Grade Systematic Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the BlackRock Investment Grade Systematic Bond Index (the “Underlying Index”), which consists of U.S. dollar-denominated, investment-grade (as determined by BlackRock Index Services, LLC (the “Index Provider”)) corporate bonds. Component securities include publicly-issued debt of U.S. corporate issuers and U.S. dollar-denominated, publicly issued debt of non-U.S. corporate issuers. As of February 28, 2026, there were 463 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by securities of companies in the consumer goods and services and financials industries or sectors. The components of the Underlying Index are likely to change over time. The securities in the Underlying Index must have $500 million or more current face amount outstanding, and have at least one year to final maturity, regardless of optionality, at time of rebalance. In addition, the securities in the Underlying Index must be denominated in U.S. dollars and have a fixed-rate, although they can carry a coupon that steps-up (i.e., changes according to a predetermined schedule). Fixed-to-Float bonds are eligible, provided that there is a minimum of 12 months until the transition date to the floating rate period. Component securities must be rated investment-grade, which is Baa3 or higher by Moody’s Investors Service, Inc. (“Moody's”) or BBB- or higher by Standard & Poor's® Global Ratings, a subsidiary of S&P Global (“S&P Global Ratings”) or Fitch Ratings, Inc. (“Fitch”). Eligibility for the Underlying Index is determined by the middle of the three available ratings. When a rating from only two agencies is available, the lower rating is used. When a rating from only one agency is available, that rating is used to determine eligibility for the Underlying Index. The Underlying Index determines constituent weights based on a proprietary methodology which first aims to systematically screen out certain bonds with the highest probability of default (a measure of credit quality) and then optimizes to improve risk-adjusted returns by weighting more heavily to bonds with attractive default-adjusted spreads (a measure of value) while mitigating portfolio risks and limiting turnover. This methodology, unlike the methodologies used by traditional market-value-weighted bond indexes, selects a portion of the component bonds from the broader universe of investment-grade bonds based on application of analytics measuring the probability of default. The resulting grouping of bonds is referred to as “enhanced,” by comparison to other groupings of investment-grade bonds, because the Underlying Index seeks to provide superior risk-adjusted and total returns over longer periods of time than a comparable market-value-weighted index. Key investment characteristics such as duration are constrained to be within a specified range of a broader market-value-weighted investment-grade bond universe. The Underlying Index is rebalanced on the last business day of each month to reflect changes in eligibility, credit quality and valuation. Investment-grade bonds included in the Underlying Index, like all investment-grade debt, continue to be subject to a number of risks, including the risk of an issuer default and volatility of the market value of the bonds. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 the Index Provider, an affiliated person of the Fund and of BFA, the Fund's investment adviser. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares 0-1 Year Treasury Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® Short US Treasury Securities Index (the “Underlying Index”), which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of less than or equal to one year. Under normal circumstances, the Fund will seek to maintain a weighted average maturity of less than one year. Weighted average maturity is the U.S. dollar weighted average of the remaining term to maturity of the underlying securities in the Fund’s portfolio. As of February 28, 2026, there were 104 issues in the Underlying Index. The Underlying Index is market value-weighted based on amounts outstanding of issuances consisting of publicly issued U.S. Treasury securities that have a remaining term to final maturity of less than or equal to one year as of the rebalance date and $1 billion or more of outstanding face value, excluding amounts held by the Federal Reserve System Open Market Account. In addition, the securities in the Underlying Index must have a fixed coupon schedule and be denominated in U.S. dollars. Excluded from the Underlying Index are inflation-linked debt and zero-coupon bonds that have been stripped from coupon-paying bonds (e.g., Separate Trading of Registered Interest and Principal of Securities). However, the amounts outstanding of qualifying coupon securities are not reduced by any individual components of such securities (i.e., coupon or principal) that have been stripped after inclusion in the Underlying Index. Securities issued or marketed primarily to retail investors do not qualify for inclusion in the Underlying Index. The Underlying Index is rebalanced on the last calendar day of each month. The Underlying Index’s cash from coupon payments and the proceeds of maturing component securities will receive a return equal to that of the ICE US 1-Month Treasury Bill Index from the point of which cash is received until the end of the month. The Underlying Index’s cash position is treated as cash and cash equivalents by the Fund, so the Fund may have material positions in cash and cash equivalents, including money market funds. Prior to October 31, 2025, the cash from coupon payments and the proceeds of maturing component securities did not earn any reinvestment income. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that 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 the percentage of investments 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 ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of the Underlying Index and publishes information regarding the market value of the Underlying Index.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. |
| iShares 0-3 Month Treasury Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® 0-3 Month US Treasury Securities Index (the “Underlying Index”), which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of less than or equal to three months. As of February 28, 2026, there were 39 issues in the Underlying Index. The Underlying Index is market value weighted based on amounts outstanding of issuances consisting of publicly issued U.S. Treasury securities that have a remaining term to final maturity of less than or equal to three months as of the rebalance date and $1 billion or more of outstanding face value, excluding amounts held by the Federal Reserve System Open Market Account. In addition, the securities in the Underlying Index must have a fixed coupon schedule and be denominated in U.S. dollars. Excluded from the Underlying Index are inflation-linked securities and zero-coupon bonds that have been stripped from coupon-paying bonds (e.g., Separate Trading of Registered Interest and Principal of Securities). However, the amounts outstanding of qualifying coupon securities are not reduced by any individual components of such securities (i.e., coupon or principal) that have been stripped after inclusion in the Underlying Index. Securities issued or marketed primarily to retail investors do not qualify for inclusion in the Underlying Index. The Underlying Index is rebalanced on the last calendar day of each month. The Underlying Index’s cash from coupon payments and the proceeds of maturing component securities receive a return equal to that of the ICE US 1-Month Treasury Bill Index from the point at which cash is received until the end of the month. The Underlying Index’s cash position is treated as cash and cash equivalents by the Fund, so the Fund may have material positions in cash and cash equivalents, including money market funds. Prior to October 31, 2025, the cash from coupon payments and the proceeds of maturing component securities did not earn any reinvestment income. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that 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 the percentage of investments 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 ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of the Underlying Index and publishes information regarding the market value of the Underlying Index.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. |
| iShares 1-3 Year Treasury Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® U.S. Treasury 1-3 Year Bond Index (the “Underlying Index”), which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than one year and less than or equal to three years. As of February 28, 2026, there were 96 issues in the Underlying Index. The Underlying Index consists of publicly-issued U.S. Treasury securities that have a remaining maturity of greater than or equal to one year and less than three years and have $300 million or more of outstanding face value, excluding amounts held by the Federal Reserve System. In addition, the securities in the Underlying Index must be fixed-rate and denominated in U.S. dollars. Excluded from the Underlying Index are inflation-linked securities, Treasury bills, cash management bills, any government agency debt issued with or without a government guarantee, original issue zero-coupon securities and zero-coupon issues that have been stripped from coupon-paying bonds. However, the amounts outstanding of qualifying securities are not reduced by any individual components of such securities (i.e., coupon or principal) that have been stripped after inclusion in the Underlying Index. Securities issued or marketed primarily to retail investors do not qualify for inclusion in the Underlying Index. The Underlying Index is market value weighted, and the securities in the Underlying Index are updated on the last calendar day of each month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that 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 the percentage of investments 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 ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of the Underlying Index and publishes information regarding the market value of the Underlying Index.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. |
| iShares 3-7 Year Treasury Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® U.S. Treasury 3-7 Year Bond Index (the “Underlying Index”), which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than three years and less than or equal to seven years. As of February 28, 2026, there were 88 issues in the Underlying Index. The Underlying Index consists of publicly-issued U.S. Treasury securities that have a remaining maturity of greater than or equal to three years and less than seven years and have $300 million or more of outstanding face value, excluding amounts held by the Federal Reserve System. In addition, the securities in the Underlying Index must be fixed-rate and denominated in U.S. dollars. Excluded from the Underlying Index are inflation-linked securities, Treasury bills, cash management bills, any government agency debt issued with or without a government guarantee, original issue zero-coupon securities and zero-coupon issues that have been stripped from coupon-paying bonds. However, the amounts outstanding of qualifying securities are not reduced by any individual components of such securities (i.e., coupon or principal) that have been stripped after inclusion in the Underlying Index. Securities issued or marketed primarily to retail investors do not qualify for inclusion in the Underlying Index. The Underlying Index is market value weighted, and the securities in the Underlying Index are updated on the last calendar day of each month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that 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 the percentage of investments 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 ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of the Underlying Index and publishes information regarding the market value of the Underlying Index.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. |
| iShares 7-10 Year Treasury Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® U.S. Treasury 7-10 Year Bond Index (the “Underlying Index”), which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than seven years and less than or equal to ten years. As of February 28, 2026, there were 13 issues in the Underlying Index. The Underlying Index consists of publicly-issued U.S. Treasury securities that have a remaining maturity of greater than or equal to seven years and less than ten years and have $300 million or more of outstanding face value, excluding amounts held by the Federal Reserve System (the “Fed”). In addition, the securities in the Underlying Index must be fixed-rate and denominated in U.S. dollars. Excluded from the Underlying Index are inflation-linked securities, Treasury bills, cash management bills, any government agency debt issued with or without a government guarantee, original issue zero-coupon securities and zero-coupon issues that have been stripped from coupon-paying bonds. However, the amounts outstanding of qualifying securities are not reduced by any individual components of such securities (i.e., coupon or principal) that have been stripped after inclusion in the Underlying Index. Securities issued or marketed primarily to retail investors do not qualify for inclusion in the Underlying Index. The Underlying Index is market value weighted, and the securities in the Underlying Index are updated on the last calendar day of each month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that 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 the percentage of investments 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 ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of the Underlying Index and publishes information regarding the market value of the Underlying Index.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. |
| iShares 10-20 Year Treasury Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® U.S. Treasury 10-20 Year Bond Index (the “Underlying Index”), which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity of greater than ten years and less than or equal to twenty years. As of February 28, 2026, there were 57 issues in the Underlying Index. The Underlying Index consists of publicly-issued U.S. Treasury securities that have a remaining maturity of greater than or equal to ten years and less than twenty years and have $300 million or more of outstanding face value, excluding amounts held by the Federal Reserve System. In addition, the securities in the Underlying Index must be fixed-rate and denominated in U.S. dollars. Excluded from the Underlying Index are inflation-linked securities, Treasury bills, cash management bills, any government agency debt issued with or without a government guarantee, original issue zero-coupon securities and zero-coupon issues that have been stripped from coupon-paying bonds. However, the amounts outstanding of qualifying securities are not reduced by any individual components of such securities (i.e., coupon or principal) that have been stripped after inclusion in the Underlying Index. Securities issued or marketed primarily to retail investors do not qualify for inclusion in the Underlying Index. The Underlying Index is market value weighted, and the securities in the Underlying Index are updated on the last calendar day of each month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that 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 the percentage of investments 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 ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of the Underlying Index and publishes information regarding the market value of the Underlying Index.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. |
| iShares 20+ Year Treasury Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® U.S. Treasury 20+ Year Bond Index (the “Underlying Index”), which measures the performance of public obligations of the U.S. Treasury that have a remaining maturity greater than twenty years. As of February 28, 2026, there were 40 issues in the Underlying Index. The Underlying Index consists of publicly-issued U.S. Treasury securities that have a remaining maturity greater than twenty years and have $300 million or more of outstanding face value, excluding amounts held by the Federal Reserve System (the “Fed”). In addition, the securities in the Underlying Index must be fixed-rate and denominated in U.S. dollars. Excluded from the Underlying Index are inflation-linked securities, Treasury bills, cash management bills, any government agency debt issued with or without a government guarantee, original issue zero-coupon securities and zero-coupon issues that have been stripped from coupon-paying bonds. However, the amounts outstanding of qualifying securities are not reduced by any individual components of such securities (i.e., coupon or principal) that have been stripped after inclusion in the Underlying Index. Securities issued or marketed primarily to retail investors do not qualify for inclusion in the Underlying Index. The Underlying Index is market value weighted, and the securities in the Underlying Index are updated on the last calendar day of each month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that 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 the percentage of investments 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 ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of the Underlying Index and publishes information regarding the market value of the Underlying Index.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. |
| iShares 25+ Year Treasury STRIPS Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® BofA® Long US Treasury Principal STRIPS Index (the “Underlying Index”), which measures the performance of long maturity Separate Trading of Registered Interest and Principal of Securities (“STRIPS”) representing the final principal payment of U.S. Treasury bonds. Qualifying principal STRIPS must have at least 25 years remaining term to final maturity and must be stripped from U.S. Treasury bonds having at least $1 billion in outstanding face value. As of February 28, 2026, there were 20 issues in the Underlying Index. Underlying Index constituents are weighted based on the market price of each constituent multiplied by an assumed face value of $1 billion per constituent. The Underlying Index is rebalanced quarterly. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that 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 the percentage of investments 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 ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of the Underlying Index and publishes information regarding the market value of the Underlying Index.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in U.S. Treasury securities that BFA believes will help the Fund track the Underlying Index. |
| iShares Agency Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the Bloomberg U.S. Agency Bond Index (the “Underlying Index”), which measures the performance of the agency sector of the U.S. government bond market and is composed of investment-grade (as determined by Bloomberg Index Services Limited (the “Index Provider” or “Bloomberg”)) U.S. dollar-denominated publicly-issued government agency bonds or debentures. As of February 28, 2026, there were 299 issues in the Underlying Index. The Underlying Index includes callable and non-callable securities issued by U.S. government agencies, quasi-federal corporations (as described below), and corporate and non-U.S. debt guaranteed by the U.S. government. A minimum 50% ownership rule is used to classify issuers as government agencies. In addition, the securities in the Underlying Index must be fixed-rate and non-convertible and have $300 million or more of outstanding face value. The Underlying Index includes securities of the following categories: •U.S. government guaranteed securities: corporate and non-U.S. issuances that carry direct guarantees from the U.S. government; •U.S. government owned, not guaranteed, securities: issuances of quasi-federal corporations (i.e., entities that are partially or wholly-owned by the U.S. government); such issuances generally carry no explicit guarantee of repayment from the U.S. government; and •U.S. government sponsored securities: issuances of U.S. government sponsored entities (including the Federal National Mortgage Association (“Fannie Mae”) and the Federal Home Loan Mortgage Corporation (“Freddie Mac”)), which are not 100% government owned, but carry out government policies and benefit from implied involvement of the U.S. government, such as by benefiting from certain government subsidies, credit provisions, or other government support; such issuances generally have no guarantees from the U.S. government. The Underlying Index represents the agency portion of the Bloomberg U.S. Aggregate Index (whose eligible universe is defined by total market issuance) that meets the selection criteria mentioned above. The Underlying Index is market-value weighted, and the securities in the Underlying Index are updated on the last business day of each month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and to-be-announced transactions (“TBAs”) that have economic characteristics that are substantially identical to the economic characteristics of the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 TBA position will be treated as part of that position for purposes of calculating the percentage of investments in the component securities of 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 the percentage of investments 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 Bloomberg, which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of the Underlying Index and publishes information regarding the market value of the Underlying Index.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and to-be-announced transactions (“TBAs”) that have economic characteristics that are substantially identical to the economic characteristics of the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| iShares California Muni Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® AMT-Free California Municipal Index (the “Underlying Index”), which measures the performance of U.S. dollar denominated investment grade tax-exempt debt publicly issued in the U.S. domestic market by the state of California and its political subdivisions. As of February 28, 2026, there were 11,290 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by municipal bonds. The components of the Underlying Index are likely to change over time. The Underlying Index includes municipal bonds issued in the State of California (“California”), the interest of which is exempt from federal income taxes and not subject to alternative minimum tax. Each bond in the Underlying Index must have a rating of at least BBB- by Standard & Poor’s® Global Ratings, a subsidiary of S&P Global, Baa3 by Moody’s Investors Service, Inc., or BBB- by Fitch Ratings, Inc. A bond must be rated by at least one of these three rating agencies in order to qualify for the Underlying Index, and the lowest rating will be used in determining if the bond is investment grade. Each bond in the Underlying Index must be a constituent of an offering where the original offering amount was at least $50 million and have a minimum par amount (i.e., currently outstanding face value) of $5 million. In addition, each bond must have a minimum remaining term to final maturity greater than or equal to one calendar month to be included in the Underlying Index. The Underlying Index is a market-value weighted index and is subject to a capping methodology that aims at reducing index concentration. The Underlying Index is rebalanced on the last calendar day of the month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments included in the Underlying Index. The Fund generally holds municipal bond securities issued by California and its municipalities whose interest payments are exempt from U.S. federal and California state income taxes and the federal alternative minimum tax (“AMT”). As of the date of this Prospectus, interest that is exempt from U.S. federal income tax is also exempt from the federal Medicare contribution tax of 3.8% on “net investment income.” In addition, the Fund intends to invest any cash assets in one or more municipal money market funds, which may be advised by BFA or its affiliates. The Fund seeks to track the investment results of the Underlying Index before fees and expenses of the Fund. The Underlying Index is sponsored by ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares Long-Term National Muni Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® Long AMT-Free US National Municipal Index (the “Underlying Index”), which measures the performance of U.S. dollar denominated investment grade tax-exempt debt publicly issued in the U.S. domestic market by U.S. states and their political subdivisions. As of February 28, 2026, there were 14,297 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by municipal bonds. The components of the Underlying Index are likely to change over time. The Underlying Index includes municipal bonds, the interest of which is exempt from federal income taxes and not subject to alternative minimum tax. Each bond in the Underlying Index must have a rating of at least BBB- by Standard & Poor’s® Global Ratings, Baa3 by Moody’s Investors Service, Inc., or BBB- by Fitch Ratings, Inc. A bond must be rated by at least one of these three rating agencies in order to qualify for the Underlying Index, and the lowest rating will be used in determining if the bond is investment grade. Each bond in the Underlying Index must be a constituent of an offering where the original offering amount was at least $50 million and have a minimum par amount (i.e., currently outstanding face value) of $10 million. In addition, each bond must have a minimum remaining term to final maturity greater than or equal to 12 years, at least three years remaining until the next call date and a fixed coupon schedule (i.e., including zero-coupon and step-up or stepdown bonds). The Underlying Index is a market-value weighted index and is subject to a capping methodology that aims at reducing index concentration. The Underlying Index is rebalanced on the last calendar day of the month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments included in the Underlying Index. The Fund will generally hold municipal bond securities issued by state and local municipalities whose interest payments are exempt from U.S. federal income taxes and the federal alternative minimum tax (“AMT”). As of the date of this Prospectus, interest that is exempt from U.S. federal income tax is also exempt from the federal Medicare contribution tax of 3.8% on “net investment income.” In addition, the Fund intends to invest any cash assets in one or more affiliated municipal money market funds, which may be advised by BFA or its affiliates. The Fund seeks to track the investment results of the Underlying Index before fees and expenses of the Fund. The Fund may invest in shares of other iShares funds that provide substantially similar exposure to the securities in the Underlying Index. BFA will waive a portion of its management fees in an amount equal to the acquired fund fees and expenses, if any, attributable to the Fund's investment in other iShares funds. The Underlying Index is sponsored by ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares MBS ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the Bloomberg U.S. MBS Index (the “Underlying Index”), which measures the performance of investment-grade (as determined by Bloomberg Index Services Limited (the “Index Provider” or “Bloomberg”)) mortgage-backed pass-through securities (“MBS”) issued and/or guaranteed by U.S. government agencies or sponsored entities. The Underlying Index includes fixed-rate MBS issued by the Government National Mortgage Association (“GNMA” or “Ginnie Mae”), Federal National Mortgage Association (“Fannie Mae”) and Federal Home Loan Mortgage Corporation (“Freddie Mac”) that have 30-, 20-, or 15-year maturities. All securities in the Underlying Index must have a remaining weighted average maturity of at least one year. In addition, the securities in the Underlying Index must be denominated in U.S. dollars and must be non-convertible. The Underlying Index is market capitalization-weighted and the securities in the Underlying Index are updated on the last business day of each month. As of February 28, 2026, there were 1,047 issues in the Underlying Index. As of February 28, 2026, approximately 100% of the bonds represented in the Underlying Index were U.S. agency MBS. Most transactions in MBS occur through standardized contracts for future delivery in which the exact mortgage pools to be delivered are not specified until a few days prior to settlement (to-be-announced (“TBA”) transactions). The Fund may enter into such contracts for fixed-rate pass-through securities on a regular basis. The Fund, pending settlement of such contracts, will invest its assets in liquid, short-term instruments, including shares of money market funds advised by BFA or its affiliates. The Fund will assume its pro rata share of the fees and expenses of any money market fund that it may invest in, in addition to the Fund's own fees and expenses. The Fund may also acquire interests in mortgage pools through means other than such standardized contracts for future delivery. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and TBAs that have economic characteristics that are substantially identical to the economic characteristics of the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 TBA position will be treated as part of that position for purposes of calculating the percentage of investments in the component securities of 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 the percentage of investments 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 Underlying Index is sponsored by Bloomberg, which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and TBAs that have economic characteristics that are substantially identical to the economic characteristics of the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares National Muni Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® AMT-Free US National Municipal Index (the “Underlying Index”), which measures the performance of U.S. dollar denominated investment grade tax-exempt debt publicly issued in the U.S. domestic market by U.S. states and their political subdivisions. As of February 28, 2026, there were 26,009 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by municipal bonds. The components of the Underlying Index are likely to change over time. The Underlying Index includes municipal bonds, the interest of which is exempt from federal income taxes and not subject to alternative minimum tax. Each bond in the Underlying Index must have a rating of at least BBB- by Standard & Poor’s® Global Ratings, Baa3 by Moody’s Investors Service, Inc., or BBB- by Fitch Ratings, Inc. A bond must be rated by at least one of these three rating agencies in order to qualify for the Underlying Index, and the lowest rating will be used in determining if the bond is investment grade. Each bond in the Underlying Index must be a constituent of an offering where the original offering amount was at least $100 million and have a minimum par amount (i.e., currently outstanding face value) of $15 million. In addition, each bond must have a minimum remaining term to final maturity greater than or equal to one calendar month to be included in the Underlying Index. The Underlying Index is a market-value weighted index and is subject to a capping methodology that aims at reducing index concentration. The Underlying Index is rebalanced on the last calendar day of the month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments included in the Underlying Index. The Fund will generally hold municipal bond securities issued by state and local municipalities whose interest payments are exempt from U.S. federal income taxes and the federal alternative minimum tax (“AMT”). As of the date of this Prospectus, interest that is exempt from U.S. federal income tax is also exempt from the federal Medicare contribution tax of 3.8% on “net investment income.” In addition, the Fund intends to invest any cash assets in one or more affiliated municipal money market funds, which may be advised by BFA or its affiliates. The Fund seeks to track the investment results of the Underlying Index before fees and expenses of the Fund. The Fund may invest in shares of other iShares funds that provide substantially similar exposure to the securities in the Underlying Index. BFA will waive a portion of its management fees in an amount equal to the acquired fund fees and expenses, if any, attributable to the Fund's investment in other iShares funds. The Underlying Index is sponsored by ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares New York Muni Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® AMT-Free New York Plus Municipal Index (the “Underlying Index”), which generally measures the performance of U.S. dollar denominated investment grade tax-exempt debt publicly issued in the U.S. domestic market by the state of New York and its political subdivisions. The Underlying Index includes a 5% weighting to U.S. dollar denominated investment grade tax-exempt debt publicly issued in the U.S. domestic market by states other than New York and such states' political subdivisions. As of February 28, 2026, there were 6,725 issues from New York and 21,700 issues from U.S. states excluding New York in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by municipal bonds. The components of the Underlying Index are likely to change over time. The Underlying Index includes municipal bonds issued in the State of New York (the “State” or “New York”), the interest of which is exempt from Federal income taxes and not subject to alternative minimum tax. Each bond in the Underlying Index must have a rating of at least BBB- by Standard & Poor’s® Global Ratings, Baa3 by Moody’s Investors Service, Inc., or BBB- by Fitch Ratings, Inc. A bond must be rated by at least one of these three rating agencies in order to qualify for the Underlying Index, and the lowest rating will be used in determining if the bond is investment grade. Each bond in the Underlying Index must be a constituent of an offering where the original offering amount was at least $20 million and have a minimum par amount (i.e., currently outstanding face value) of $5 million. In addition, each bond must have a minimum remaining term to final maturity greater than or equal to one calendar month to be included in the Underlying Index. The Underlying Index also includes municipal bonds issued in U.S. states other than New York that are subject to the same selection criteria. The Underlying Index is a market-value weighted index and is subject to a capping methodology that aims at reducing index concentration. The Underlying Index is rebalanced on the last calendar day of the month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments included in the Underlying Index. The Fund generally holds municipal bond securities issued by New York and its municipalities whose interest payments are exempt from U.S. federal and New York state income taxes and the federal alternative minimum tax (“AMT”). As of the date of this Prospectus, interest that is exempt from U.S. federal income tax is also exempt from the federal Medicare contribution tax of 3.8% on “net investment income.” In addition, the Fund intends to invest any cash assets in one or more affiliated municipal money market funds, which may be advised by BFA or its affiliates. The Fund seeks to track the investment results of the Underlying Index before fees and expenses of the Fund. The Underlying Index is sponsored by ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares Short-Term National Muni Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the ICE® Short Maturity AMT-Free US National Municipal Index (the “Underlying Index”), which measures the performance of short maturity U.S. dollar denominated investment grade tax-exempt debt publicly issued in the U.S. domestic market by U.S. states and their political subdivisions. As of February 28, 2026, there were 21,176 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by municipal bonds. The components of the Underlying Index are likely to change over time. The Underlying Index includes municipal bonds, the interest of which is exempt from federal income taxes and not subject to alternative minimum tax. Each bond in the Underlying Index must have a rating of at least BBB- by Standard & Poor’s® Global Ratings, Baa3 by Moody’s Investors Service, Inc., or BBB- by Fitch Ratings, Inc. A bond must be rated by at least one of these three rating agencies in order to qualify for the Underlying Index, and the lowest rating will be used in determining if the bond is investment grade. Each bond in the Underlying Index must be a constituent of an offering where the original offering amount was at least $50 million and have a minimum par amount (i.e., currently outstanding face value) of $5 million. In addition, each bond must have a remaining term to final maturity that is less than five years and greater than or equal to one calendar month to be included in the Underlying Index. The Underlying Index is a market-value weighted index and is subject to a capping methodology that aims at reducing index concentration. The Underlying Index is rebalanced on the last calendar day of the month. Under normal circumstances, the Fund will seek to maintain a weighted average maturity that is less than three years. Weighted average maturity is a U.S. dollar-weighted average of the remaining term to maturity of the underlying securities in the Fund’s portfolio. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments included in the Underlying Index. The Fund will generally hold municipal bond securities issued by state and local municipalities whose interest payments are exempt from U.S. federal income taxes and the federal alternative minimum tax (“AMT”). As of the date of this Prospectus, interest that is exempt from U.S. federal income tax is also exempt from the federal Medicare contribution tax of 3.8% on “net investment income.” In addition, the Fund intends to invest any cash assets in one or more affiliated municipal money market funds, which may be advised by BFA or its affiliates. The Fund seeks to track the investment results of the Underlying Index before fees and expenses of the Fund. The Underlying Index is sponsored by ICE Data Indices, LLC (the “Index Provider” or “IDI”), which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares Broad USD Floating Rate Loan ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the Morningstar LSTA US Leveraged Loan Broad Select Index (the “Underlying Index”), which was developed by Morningstar, Inc. (“Morningstar” or the “Index Provider”). The Underlying Index is a market value-weighted index designed to measure the performance of a subset of the U.S. dollar-denominated, senior secured institutional floating rate loan market. Floating rate loans, which are also known as leveraged loans or bank loans, provide for periodic adjustment in the interest rate paid on the loan and are typically senior secured, below-investment grade instruments. These loans are characterized by higher interest rates due to the increased risk associated with lending to borrowers with higher debt levels. They are often used for refinancing debt, merger and acquisitions funding, or recapitalization. Such loans typically are secured by collateral such as borrowers’ property, equipment or intellectual property. Borrowers of floating rate loans operate in various industries and geographic areas, including non-U.S. jurisdictions. To be eligible for inclusion in the Underlying Index, a loan must be a USD-denominated institutional first lien loan with (i) a par amount outstanding of at least $1 billion, (ii) at least 18 months to final maturity and (iii) a rating of BB+ or lower by S&P Global Ratings. Defaulted, D-rated, non-rated and payment in kind loans are excluded. Eligible loans must have at least 125 basis points of spread above the “base rate,” which the Index Provider defines as the average of the 30-day rolling average of 1-month CME Term SOFR and the 90-day rolling average of 3-month CME Term SOFR. All loans in the Underlying Index must be syndicated in the United States, but issuers may be domiciled or operate outside the U.S. Constituent weights are subject to a 2% issuer cap. The Underlying Index is reconstituted and rebalanced weekly. Existing constituents with less than 12 months remaining to final maturity or a par amount outstanding of less than $900 million are removed at each rebalance and reconstitution. Loans that default, are downgraded to a D rating, are repaid or are no longer priced are removed at the next rebalance. The Fund generally purchases loans from banks or other financial institutions through an assignment, in which the existing lender transfers its rights, interests and obligations in the assigned loan to the Fund. The Fund also generally sells loans that it holds through an assignment. In addition, the Fund may acquire or sell an interest in a loan through a participation, which involves buying or selling a portion of a loan from another lender. As of February 28, 2026, there were 496 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by loans to companies in the consumer goods and services, industrials and technology industries or sectors. The components of the Underlying Index are likely to change over time. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the components of the Underlying Index. The Fund may hold loans that have not yet entered the Underlying Index or that have been removed from the Underlying Index. For liquidity purposes, the Fund may invest in other types of instruments, including high-yield securities, derivatives (including interest rate futures and swaps), ETFs, short-term government notes, repurchase agreements, commercial paper, non-index loans, high-quality collateralized loan obligations and cash. The Fund may also hold interest rate swaps or other derivatives for hedging purposes. Cash and cash equivalent investments associated with a derivative position will be treated as part of that position for the purposes of calculating the percentage of investments 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 acquire and hold common stocks, warrants or other equity securities (or rights to acquire such securities or warrants) in unit offerings with fixed income securities, in connection with an amendment, waiver, conversion or exchange of fixed income securities, in connection with the bankruptcy or workout of a distressed fixed income security, or upon the exercise of a right or warrant obtained on account of a fixed income security. 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 loans 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the components of the Underlying Index. The Fund may hold loans that have not yet entered the Underlying Index or that have been removed from the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares Core 5-10 Year USD Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the Bloomberg U.S. Universal 5-10 Year Index (the “Underlying Index”), which measures the performance of U.S. dollar-denominated taxable bonds that are rated either investment-grade or high yield (as determined by Bloomberg Index Services Limited (the “Index Provider” or “Bloomberg”)) with remaining effective maturities between five and ten years. The Underlying Index includes U.S. Treasury bonds, government-related bonds (i.e., U.S. and non-U.S. agencies, sovereign, quasi-sovereign, supranational and local authority debt), investment-grade and high yield U.S. corporate bonds, mortgage-backed pass-through securities (“MBS”), commercial mortgage-backed securities (“CMBS”), asset-backed securities (“ABS”), Eurodollar bonds (i.e., U.S. dollar-denominated bonds issued by foreign issuers outside the U.S.), bonds registered with the SEC or exempt from registration at the time of issuance, or offered pursuant to Rule 144A under the Securities Act of 1933, as amended (the “1933 Act”) with or without registration rights (“Rule 144A Bonds”) and emerging market bonds. The Underlying Index is a subset of the Bloomberg U.S. Universal Index. As of February 28, 2026, there were 6,003 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by MBS and U.S. Treasury securities. MBS eligible for the index include 20-year and 30-year mortgages because their effective duration has historically been more consistent with the duration of non-callable 5-10 year bonds due to prepayments. The components of the Underlying Index are likely to change over time. The securities in the Underlying Index must be denominated in U.S. dollars and non-convertible. Excluded from the Underlying Index are tax-exempt municipal securities, coupon issues that have been stripped from bonds, structured notes, private placements (excluding Rule 144A Bonds) and inflation-linked bonds. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and to-be-announced transactions (“TBAs”) that have economic characteristics that are substantially identical to the economic characteristics of the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 TBA position will be treated as part of that position for purposes of calculating the percentage of investments in the component securities of 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 the percentage of investments 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 Bloomberg, which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and to-be-announced transactions (“TBAs”) that have economic characteristics that are substantially identical to the economic characteristics of the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares Core 10+ Year USD Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the Bloomberg U.S. Universal 10+ Year Index (the “Underlying Index”), which measures the performance of U.S. dollar-denominated taxable bonds that are rated either investment-grade or high yield (as determined by Bloomberg Index Services Limited (the “Index Provider” or “Bloomberg”)) with remaining maturities greater than ten years. The Underlying Index includes U.S. Treasury bonds, government-related bonds (i.e., U.S. and non-U.S. agencies, sovereign, quasi-sovereign, supranational and local authority debt), investment-grade and high yield U.S. corporate bonds, Eurodollar bonds (i.e., U.S. dollar-denominated bonds issued by foreign issuers outside the U.S.), bonds registered with the SEC or exempt from registration at the time of issuance, or offered pursuant to Rule 144A under the Securities Act of 1933, as amended (the “1933 Act”) with or without registration rights (“Rule 144A Bonds”) and emerging market bonds. The Underlying Index is a subset of the Bloomberg U.S. Universal Index. As of February 28, 2026, there were approximately 4,485 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by U.S. Treasury securities. The components of the Underlying Index are likely to change over time. The securities in the Underlying Index must have at least 10 years remaining to maturity, or at least 10 years remaining to the first call date in the case of callable perpetual securities. In addition, the securities in the Underlying Index must be denominated in U.S. dollars and be non-convertible. Excluded from the Underlying Index are tax-exempt municipal securities, coupon issues that have been stripped from bonds, structured notes and private placements (excluding Rule 144A Bonds). The Underlying Index is market capitalization-weighted and is rebalanced on the last day of the month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and to-be-announced transactions (“TBAs”) that have economic characteristics that are substantially identical to the economic characteristics of the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 TBA position will be treated as part of that position for purposes of calculating the percentage of investments in the component securities of 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 the percentage of investments 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 Bloomberg, which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and to-be-announced transactions (“TBAs”) that have economic characteristics that are substantially identical to the economic characteristics of the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares Core U.S. Aggregate Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the Bloomberg U.S. Aggregate Bond Index (the “Underlying Index”), which measures the performance of the total U.S. investment-grade (as determined by Bloomberg Index Services Limited (the “Index Provider” or “Bloomberg”)) bond market. As of February 28, 2026, there were 13,972 issues in the Underlying Index. The Underlying Index includes investment-grade U.S. Treasury bonds, government-related bonds, corporate bonds, mortgage-backed pass-through securities (“MBS”), commercial mortgage-backed securities (“CMBS”) and asset-backed securities (“ABS”) that are publicly offered for sale in the U.S. As of February 28, 2026, a significant portion of the Underlying Index was represented by MBS and U.S. Treasury securities. The components of the Underlying Index are likely to change over time. The securities in the Underlying Index must have $300 million or more of outstanding face value and must have at least one year remaining to maturity, with the exception of amortizing securities such as ABS and MBS, which have lower minimum thresholds as defined by Bloomberg. In addition, the securities in the Underlying Index must be denominated in U.S. dollars and must be fixed-rate, non-convertible and taxable. Certain types of securities, such as state and local government series bonds, structured notes with embedded swaps or other special features, private placements, floating-rate securities and bonds that have been issued in one country's currency but are traded outside of that country in a different monetary and regulatory system (e.g., Eurobonds), are excluded from the Underlying Index. The Underlying Index is market capitalization-weighted, and the securities in the Underlying Index are updated on the last business day of each month. U.S. fixed-rate agency MBS are issued by entities such as the Government National Mortgage Association (“Ginnie Mae”), the Federal National Mortgage Association (“Fannie Mae”), and the Federal Home Loan Mortgage Corporation (“Freddie Mac”) and are backed by pools of mortgages. Most transactions in fixed-rate MBS occur through standardized contracts for future delivery in which the exact mortgage pools to be delivered are not specified until a few days prior to settlement (to-be-announced (“TBA”) transactions). The Fund may enter into such contracts on a regular basis. The Fund, pending settlement of such contracts, will invest its assets in high-quality, liquid short-term instruments, including shares of money market funds advised by BFA or its affiliates. The Fund will assume its pro rata share of the fees and expenses of any money market fund that it may invest in, in addition to the Fund's own fees and expenses. The Fund may also acquire interests in mortgage pools through means other than such standardized contracts for future delivery. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and TBAs that have economic characteristics that are substantially identical to the economic characteristics of the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 TBA position will be treated as part of that position for purposes of calculating the percentage of investments in the component securities of 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 the percentage of investments 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 Bloomberg, which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and TBAs that haveeconomic characteristics that are substantially identical to the economic characteristics of the component securities of theUnderlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in theUnderlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares ESG Advanced Universal USD Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investments results of the Bloomberg MSCI US Universal Choice ESG Screened Index (the “Underlying Index”), which has been developed by Bloomberg Finance L.P. and its affiliates (the “Index Provider” or “Bloomberg”) with environmental, social and governance (“ESG”) rating inputs from MSCI Solutions LLC (“MSCI Solutions”) pursuant to an agreement between MSCI Solutions and Bloomberg Index Services Limited (a subsidiary of Bloomberg) or an affiliate. The Underlying Index is a modified market value-weighted index designed to reflect the performance of U.S. dollar-denominated, taxable bonds with favorable ESG ratings (as determined by MSCI Solutions) while applying extensive screens, including, for example, a screen which focuses on removing fossil fuel exposure. To construct the Underlying Index, Bloomberg begins with the Bloomberg U.S. Universal Index (the “Parent Index”). The Parent Index includes securities with at least one year until final maturity, without regard to optionality features such as call provisions or conversion provisions. The Parent Index includes Treasury securities, government-related securities (i.e., U.S. and non-U.S. agency debt securities, and non-U.S. sovereign, quasi-sovereign, supranational and local authority debt), investment-grade and high yield (as well as unrated) corporate bonds, U.S. agency mortgage-backed pass-through securities (“MBS”), commercial mortgage-backed securities, asset backed securities, Eurodollar bonds, bonds registered with the SEC or exempt from registration at the time of issuance or offered pursuant to Rule 144A with or without registration rights and U.S. dollar-denominated emerging market bonds. From the Parent Index, Bloomberg excludes issuers with unfavorable ESG ratings, as calculated by MSCI Solutions, and then further excludes securities of issuers involved in adult entertainment, alcohol, gambling, tobacco, genetic engineering, controversial weapons, nuclear weapons, civilian firearms, conventional weapons, palm oil, private prisons, predatory lending, and nuclear power based on revenue or percentage of revenue thresholds for certain categories (e.g., $500 million or 50%) and categorical exclusions for others (e.g., nuclear weapons). Bloomberg screens companies with involvement in fossil fuels by excluding any company in the Bloomberg energy sector and all companies with an industry tie to fossil fuels such as thermal coal, oil and gas—in particular, reserve ownership, related revenues and power generation. Additionally, Bloomberg excludes companies involved in very serious business controversies. For each industry, MSCI Solutions identifies key ESG issues that can lead to unexpected costs for entities in the medium- to long-term (e.g., climate change, resource scarcity, demographic shifts). MSCI Solutions then calculates the size of each entity's exposure to each key issue based on the entity's business segment and geographic risk and analyzes the extent to which such entities have developed robust strategies and programs to manage ESG risks and opportunities. MSCI Solutions scores entities based on both their risk exposure and risk management. To score well on a key issue, MSCI Solutions 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, entities 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 entities. As of February 28, 2026, there were 10,338 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by U.S. agency MBS and U.S. Treasury bonds. The components of the Underlying Index are likely to change over time. The securities in the Underlying Index are updated on the last business day of each month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and in investments that have economic characteristics that are substantially identical to the component securities of the Underlying Index (i.e., TBAs), and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options, and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 Bloomberg, MSCI Solutions or their affiliates, which are independent of the Fund and BFA, pursuant to an agreement between MSCI Solutions and Bloomberg Index Services Limited (a subsidiary of Bloomberg) or an affiliate. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and in investments that have economic characteristics that are substantially identical to the component securities of the Underlying Index (i.e., TBAs), and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares ESG Aware U.S. Aggregate Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the Bloomberg MSCI US Aggregate ESG Focus Index (the “Underlying Index”), which has been developed by Bloomberg Finance L.P. and its affiliates (the “Index Provider” or “Bloomberg”) with environmental, social and governance (“ESG”) rating inputs from MSCI Solutions LLC (“MSCI Solutions”) pursuant to an agreement between MSCI Solutions and Bloomberg Index Services Limited (a subsidiary of Bloomberg) or an affiliate. The Underlying Index is an optimized fixed-income index designed to reflect the performance of U.S. dollar-denominated, investment-grade (as determined by the Index Provider) bonds from issuers generally evaluated for favorable ESG practices (as determined by MSCI Solutions), while seeking to exhibit risk and return characteristics similar to those of the Bloomberg US Aggregate Bond Index (the “Parent Index”). The Underlying Index includes investment-grade U.S. Treasury bonds, non-securitized government-related bonds (“government-related bonds”), corporate bonds, mortgage-backed pass-through securities (“MBS”), commercial mortgage-backed securities (“CMBS”) and asset-backed securities (“ABS”) that are publicly offered for sale in the U.S. To construct the Underlying Index, the Index Provider begins with the Parent Index and replicates its U.S. Treasury bond, MBS, CMBS and ABS exposures. These exposures are preserved at the weights of the Parent Index and are not subject to the Index Provider’s optimization process, which is a quantitative process that seeks to determine optimal weights for securities to maximize exposure to securities of entities with higher MSCI Solutions ratings, while seeking to exhibit risk and return characteristics similar to the Parent Index. At each quarterly review, the Underlying Index must have an ESG score of at least 10% better than that of the Parent Index, as determined by Bloomberg and MSCI. For the remaining constituents of the Parent Index (i.e., corporate bonds and government-related bonds), the Index Provider excludes securities of entities involved in the business of tobacco, entities involved with controversial weapons, producers and retailers of civilian firearms, companies involved in certain fossil fuels-related activity (such as the production of thermal coal, thermal coal-based power generation and extraction of oil sands) based on revenue or percentage of revenue thresholds for certain categories (e.g., $20 million or 5%) and categorical exclusions for others (e.g., controversial weapons). The Index Provider also excludes entities involved in very severe business controversies (in each case as determined by MSCI Solutions), and securities of entities without an MSCI Solutions rating, and then follows the Index Provider’s optimization process. For each industry, MSCI Solutions identifies key ESG issues that can lead to substantial costs or opportunities for entities (e.g., climate change, resource scarcity, demographic shifts). MSCI Solutions then rates each entity’s exposure to each key issue based on the entity’s business segment and geographic risk and analyzes the extent to which entities have developed robust strategies and programs to manage ESG risks and opportunities. MSCI Solutions scores entities based on both their risk exposure and risk management. To score well on a key issue, MSCI Solutions 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, entities 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 entities. The securities in the Underlying Index must have at least one year remaining to maturity, with the exception of amortizing securities such as ABS and MBS, which have lower thresholds as defined by the Index Provider. In addition, the securities in the Underlying Index must be denominated in U.S. dollars and must be fixed-rate and nonconvertible. Certain types of securities, such as state and local government series bonds, structured notes with embedded swaps or other special features, private placements (other than those offered pursuant to Rule 144A or Regulation S promulgated under the Securities Act of 1933, as amended (the “1933 Act”)), floating rate securities and bonds that have been issued in one country’s currency but are traded outside of that country in a different monetary and regulatory system (e.g., Eurobonds), are excluded from the Underlying Index. The securities in the Underlying Index are updated on the last business day of each month. As of February 28, 2026, there were 7,563 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by MBS and U.S. Treasury securities. The components of the Underlying Index are likely to change over time. U.S. fixed-rate agency MBS are securities issued by entities such as the Government National Mortgage Association (“Ginnie Mae”), the Federal National Mortgage Association (“Fannie Mae”), and the Federal Home Loan Mortgage Corporation (“Freddie Mac”) and are backed by pools of mortgages. U.S. fixed-rate agency MBS exposure does not receive any MSCI Solutions rating as the Index Provider believes that U.S. fixed-rate agency MBS exposure is neither additive nor decremental to the Underlying Index's ESG rating profile. As such, based on currently available data, the Index Provider believes U.S. fixed-rate agency MBS exposure is ESG neutral and not inconsistent with an ESG focused exposure. Most transactions in fixed-rate MBS occur through standardized contracts for future delivery in which the exact mortgage pools to be delivered are not specified until a few days prior to settlement (to-be-announced (“TBA”) transactions). The Fund may enter into such contracts on a regular basis. The Fund, pending settlement of such contracts, will invest its assets in high-quality, liquid short-term instruments, including shares of money market funds advised by BFA or its affiliates. The Fund will assume its pro rata share of the fees and expenses of any money market fund that it may invest in, in addition to the Fund’s own fees and expenses. The Fund may also acquire interests in mortgage pools through means other than such standardized contracts for future delivery. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and in investments that have economic characteristics that are substantially identical to the component securities of the Underlying Index (i.e., TBAs), and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options, and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 Bloomberg, MSCI Solutions or their affiliates, which are independent of the Fund and BFA, pursuant to an agreement between MSCI Solutions and Bloomberg Index Services Limited (a subsidiary of Bloomberg) or an affiliate. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and in investments thathave economic characteristics that are substantially identical to the component securities of the Underlying Index (i.e., TBAs),and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares Government/Credit Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the Bloomberg U.S. Government/Credit Bond Index (the “Underlying Index”), which measures the performance of U.S. dollar-denominated U.S. Treasury bonds, government-related bonds (i.e., U.S. and foreign agencies, sovereign, supranational and local authority debt) and investment-grade (as determined by Bloomberg Index Services Limited (the “Index Provider” or “Bloomberg”)) U.S. corporate bonds that have a remaining maturity of greater than or equal to one year. As of February 28, 2026, there were 10,082 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by U.S. Treasury securities. The components of the Underlying Index are likely to change over time. The Underlying Index consists of U.S. government, government-related and investment-grade U.S. credit securities that have greater than or equal to one year remaining to maturity and have $300 million or more of outstanding face value. In addition, the securities in the Underlying Index must be denominated in U.S. dollars and must be fixed-rate and non-convertible. Excluded from the Underlying Index are certain special issues such as targeted investor notes, state and local government series bonds and coupon issues that have been stripped from bonds. Also excluded from the Underlying Index are structured notes with embedded swaps or other special features, private placements, floating-rate securities and bonds that have been issued in one country's currency but are traded outside of that country in a different monetary and regulatory system (e.g., Eurobonds). The Underlying Index is market capitalization-weighted and the securities in the Underlying Index are updated on the last business day of each month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 Bloomberg, which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares Intermediate Government/Credit Bond ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the Bloomberg U.S. Intermediate Government/Credit Bond Index (the “Underlying Index”), which measures the performance of U.S. dollar-denominated U.S. Treasury bonds, government-related bonds (i.e., U.S. and non-U.S. agencies, sovereign, supranational and local authority debt) and investment-grade (as determined by Bloomberg Index Services Limited (the “Index Provider” or “Bloomberg”)) U.S. corporate bonds that have a remaining maturity of greater than one year and less than ten years. As of February 28, 2026, there were 6,518 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by U.S. Treasury securities. The components of the Underlying Index are likely to change over time. The Underlying Index consists of U.S. government, government-related and investment-grade U.S. credit securities that have greater than one year and less than ten years remaining to maturity and have $300 million or more of outstanding face value. In addition, the securities in the Underlying Index must be denominated in U.S. dollars and must be fixed-rate and non-convertible. Excluded from the Underlying Index are certain special issues such as targeted investor notes, state and local government series bonds and coupon issues that have been stripped from bonds. Also excluded from the Underlying Index are structured notes with embedded swaps or other special features, private placements, floating-rate securities and bonds that have been issued in one country's currency but are traded outside of that country in a different monetary and regulatory system (e.g., Eurobonds). The Underlying Index is market capitalization-weighted and the securities in the Underlying Index are updated on the last business day of each month. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 the percentage of investments 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 Bloomberg, which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |
| iShares Total USD Fixed Income Market ETF | |
| Prospectus [Line Items] | |
| Strategy [Heading] | Principal Investment Strategies |
| Strategy Narrative [Text Block] | The Fund seeks to track the investment results of the Bloomberg U.S. Total Fixed Income Market Index (the “Underlying Index”), which measures the performance of U.S. dollar-denominated fixed income securities that are rated either investment-grade or high yield (as determined by Bloomberg Index Services Limited (the “Index Provider” or “Bloomberg”)). The Underlying Index includes fixed and floating rate U.S. Treasury bonds, U.S. Treasury Inflation-Protected Securities (“TIPS”), government-related bonds, investment-grade and high yield U.S. corporate bonds, securitized assets, fixed and floating rate notes and corporate bonds, leveraged loans, Eurodollar bonds, bonds registered with the SEC or exempt from registration at the time of issuance or offered pursuant to Rule 144A with or without registration rights and U.S. dollar- denominated emerging market bonds. The securities in the Underlying Index must be denominated in U.S. dollars. The Underlying Index consisted of securities from 110 countries or regions as of February 28, 2026. As of February 28, 2026, there were 22,707 issues in the Underlying Index. As of February 28, 2026, a significant portion of the Underlying Index was represented by U.S. agency mortgage-backed securities and U.S. Treasury bonds. The components of the Underlying Index are likely to change over time. BFA uses an indexing approach to try to achieve the Fund’s investment objective. 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 or other instruments that collectively has an investment profile similar to that of an applicable underlying index. The instruments selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., an instrument's price sensitivity to a change in interest rates), maturity or 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 components of the Underlying Index. The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and to-be-announced transactions (“TBAs”) that have economic characteristics that are substantially identical to the economic characteristics of the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types 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 TBA position will be treated as part of that position for purposes of calculating investments in the component securities of 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 the percentage of investments 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 Bloomberg, which is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the components of 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.
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| Rule 35d-1 Eighty Percent Investment Policy [Text Block] | The Fund will invest at least 80% of its assets in the component securities of the Underlying Index and to-be-announced transactions (“TBAs”) that have economic characteristics that are substantially identical to the economic characteristics of the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. |
| Strategy Portfolio Concentration [Text] | 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. |