485BPOS

As filed with the U.S. Securities and Exchange Commission on March 18, 2019

Securities Act File No. 333-179904

Investment Company Act File No. 811-22649

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933	☒
Pre-Effective Amendment No.	☐
Post-Effective Amendment No. 473	☒
and/or

REGISTRATION STATEMENT

UNDER

THE INVESTMENT COMPANY ACT OF 1940	☒
Amendment No. 473	☒
(Check appropriate box or boxes)

iShares U.S. ETF Trust

(Exact Name of Registrant as Specified in Charter)

c/o State Street Bank and Trust Company

1 Lincoln Street

Mail Stop SUM0703

Boston, MA 02111

(Address of Principal Executive Office) (Zip Code)

Registrant’s Telephone Number, including Area Code (415) 670-2000

The Corporation Trust Company

1209 Orange Street

Wilmington, DE 19801

(Name and Address of Agent for Service)

With Copies to:

MARGERY K. NEALE, ESQ.
WILLKIE FARR &
GALLAGHER LLP
787 SEVENTH AVENUE
NEW YORK, NY 10019-6099 DEEPA DAMRE, ESQ. BLACKROCK FUND ADVISORS 400 HOWARD STREET SAN FRANCISCO, CA 94105

Continuous

(March 18, 2019)

It is proposed that this filing will become effective:

☒ immediately upon filing pursuant to paragraph (b)

☐ on (date) pursuant to paragraph (b)

☐ 60 days after filing pursuant to paragraph (a)(1)

☐ on (date) pursuant to paragraph (a)(1)

☐ 75 days after filing pursuant to paragraph (a)(2)

☐ on (date) pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following box:

☐ This post-effective amendment designates a new effective date for a previously filed post-effective amendment.

This filing relates solely to the following Funds, each a series of iShares U.S. ETF Trust:

iShares Bloomberg Roll Select Commodity Strategy ETF

iShares Commodities Select Strategy ETF

iShares Gold Strategy ETF

iShares Inflation Hedged Corporate Bond ETF

iShares Interest Rate Hedged Corporate Bond ETF

iShares Interest Rate Hedged Emerging Markets Bond ETF

iShares Interest Rate Hedged High Yield Bond ETF

iShares Interest Rate Hedged Long-Term Corporate Bond ETF

iShares Short Maturity Bond ETF

iShares Short Maturity Municipal Bond ETF

iShares Ultra Short-Term Bond ETF

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, the Registrant certifies that it meets all the requirements for the effectiveness of this Registration Statement pursuant to Rule 485(b) under the Securities Act of 1933, as amended, and has duly caused this Post-Effective Amendment No. 473 to the Registration Statement to be signed on its behalf by the undersigned, duly authorized, in the City of San Francisco and the State of California on the 15^th day of March, 2019.

iSHARES U.S. ETF TRUST

By:
	Martin Small*
	President
Date:	March 15, 2019

Pursuant to the requirements of the Securities Act of 1933, as amended, this Post-Effective Amendment No. 473 to the Registration Statement has been signed below by the following persons in the capacities and on the date indicated.

Mark K. Wiedman*

Trustee

Date: March 15, 2019

John E. Martinez*

Trustee

Date: March 15, 2019

Cecilia H. Herbert*

Trustee

Date: March 15, 2019

John E. Kerrigan*

Trustee

Date: March 15, 2019

Robert S. Kapito*

Trustee

Date: March 15, 2019

Madhav V. Rajan*

Trustee

Date: March 15, 2019

Jane D. Carlin*

Trustee

Date: March 15, 2019

- 2 -

Drew E. Lawton**

Trustee

Date: March 15, 2019

Richard L. Fagnani**

Trustee

Date: March 15, 2019

/s/ Jack Gee

Jack Gee*

Treasurer and Chief Financial Officer

Date: March 15, 2019

/s/ Jack Gee

* By: Jack Gee

Attorney-in-fact

Date: March 15, 2019

* Powers of Attorney, each dated October 15, 2016, for Martin Small, Jane D. Carlin, Mark Wiedman, Cecilia H. Herbert, John E. Kerrigan, John E. Martinez, Madhav V. Rajan, Robert S. Kapito and Jack Gee are incorporated herein by reference to Post-Effective Amendment No. 236, filed November 15, 2016.

** Powers of Attorney, each dated June 21, 2017, for Drew E. Lawton and Richard L. Fagnani are incorporated herein by reference to Post-Effective Amendment No. 298, filed November 1, 2017.

- 3 -

EXHIBIT INDEX

Index No.	Description of Exhibit
EX-101.INS	XBRL Instance Document
EX-101.SCH	XBRL Taxonomy Extension Schema Document
EX-101.CAL	XBRL Taxonomy Extension Calculation Linkbase
EX-101.DEF	XBRL Taxonomy Extension Definition Linkbase
EX-101.LAB	XBRL Taxonomy Extension Labels Linkbase
EX-101.PRE	XBRL Taxonomy Extension Presentation Linkbase

- 4 -

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Document Type	dei_DocumentType	485BPOS
Document Period End Date	dei_DocumentPeriodEndDate	Oct. 31, 2018
Registrant Name	dei_EntityRegistrantName	iShares U.S. ETF Trust
Central Index Key	dei_EntityCentralIndexKey	0001524513
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Feb. 22, 2019
Document Effective Date	dei_DocumentEffectiveDate	Mar. 01, 2019
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
Entity Inv Company Type	dei_EntityInvCompanyType	N-1A

XML

iShares Bloomberg Roll Select Commodity Strategy ETF

iSHARES^® BLOOMBERG ROLL SELECT COMMODITY STRATEGY ETF<br/>Ticker: CMDY                                  Stock Exchange: NYSE Arca

<b>Investment Objective</b>

The iShares Bloomberg Roll Select Commodity Strategy ETF (the “Fund”) seeks to provide exposure, on a total return basis, to a diversified group of commodities.

<b>Fees and Expenses</b>

The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities, commodities or other financial instruments and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and any extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”). BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees in an amount equal to the Acquired Fund Fees and Expenses, if any, attributable to investments by the Fund in other funds advised by BFA, or its affiliates, through February 28, 2025. The contractual waiver may be terminated prior to February 28, 2025 only upon written agreement of the Trust and BFA.

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

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

Annual Fund Operating Expenses		Management Fees	Distribution and Service (12b-1) Fees	Other Expenses	Acquired Fund Fees and Expenses	Total Annual Fund Operating Expenses	Fee Waiver	Total Annual Fund Operating Expenses After Fee Waiver
iShares Bloomberg Roll Select Commodity Strategy ETF | iShares Bloomberg Roll Select Commodity Strategy ETF	[1]	0.28%	none	none	0.01%	0.29%	(0.01%)	0.28%

<b>Example. </b>

This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example	1 Year	3 Years	5 Years	10 Years
iShares Bloomberg Roll Select Commodity Strategy ETF | iShares Bloomberg Roll Select Commodity Strategy ETF | USD ($)	29	90	157	362

<b>Portfolio Turnover.</b>

The Fund may pay transaction costs, such as commissions, when it, directly or indirectly through a subsidiary, buys and sells securities or other assets (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. From inception (April 3, 2018) to the most recent fiscal year end, the Fund's portfolio turnover rate was 0% of the average value of its portfolio.

<b>Principal Investment Strategies </b>

The Fund seeks to achieve its investment objective by investing in exchange-traded futures contracts on the Bloomberg Roll Select Commodity Index (the “Index Futures”). The Fund is expected to roll out of existing positions in Index Futures and establish new positions in Index Futures on an ongoing basis. Index Futures subsequently acquired by the Fund may have terms that differ from those of the Index Futures it currently holds and the purchase and sale of these Index Futures may incur transaction fees. In seeking total return, the Fund also seeks to generate interest income and capital appreciation on the cash balances arising from its investment in Index Futures through a cash management strategy consisting of investments in cash and cash equivalents, short-term government obligations and short-term investment-grade fixed-income securities (collectively, “Fixed-Income Investments”).

The Fund is an actively managed exchange-traded fund (“ETF”) and does not seek to replicate the performance of a specified index. While the Fund is not an index fund, the Fund’s investment strategy seeks to maximize correlation with the Bloomberg Roll Select Commodity Index (the Bloomberg Benchmark), which is composed of 22 futures contracts across 20 physical agricultural, energy, precious metals and industrial metals commodities. The Bloomberg Benchmark reflects the returns from these commodity futures contracts, and provides broad-based exposure to commodities as an asset class by using liquidity factors and sector caps to avoid over-concentration in any single commodity or commodity sector. In order to maintain exposure to a futures contract on a particular commodity, an investor must sell the position in the expiring contract and buy a new position in a contract with a later delivery month, which is referred to as “rolling.” If the price for the new futures contract is less than the price of the expiring contract, then the market for the commodity is said to be in “backwardation.” In these markets, roll returns are positive, which is referred to as “positive carry.” The term “contango” is used to describe a market in which the price for a new futures contract is more than the price of the expiring contract. In these markets, roll returns are negative, which is referred to as “negative carry.” The Bloomberg Benchmark seeks to employ a positive carry strategy that emphasizes commodities and futures contract months with the greatest degree of backwardation and lowest degree of contango, resulting in net gains through positive roll returns.

The Fund will invest in financial instruments providing exposure to commodities and not in the physical commodities themselves. The Fund may also invest in exchange-traded commodity futures contracts similar to those found in the Bloomberg Benchmark, as well as swaps and options on futures that correlate to the investment returns of commodities without investing directly in physical commodities and over-the-counter commodity-linked instruments like commodity-linked notes, swaps and forward contracts (together, the “Commodity Investments”). Investing in derivative contracts may have a leveraging effect on the Fund. Although the Fund may hold the same futures contracts under the same futures rolling schedule as those included in the Bloomberg Benchmark, the Fund is not obligated to invest in any futures contracts included in, and does not seek to replicate the performance of, the Bloomberg Benchmark.

The Fund seeks to gain exposure to Index Futures and other Commodity Investments by investing through a wholly-owned subsidiary organized in the Cayman Islands (the “Subsidiary”). The Subsidiary is advised by BFA and has the same investment objective as the Fund. Unlike the Fund, the Subsidiary is not an investment company registered under the Investment Company Act of 1940, as amended (the “1940 Act”). The Subsidiary invests solely in Commodity Investments and cash and cash equivalents. In compliance with Subchapter M of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”), the Fund may invest up to 25% of its total assets in the Subsidiary. The Fund’s Commodity Investments held in the Subsidiary are intended to provide the Fund with exposure to broad commodities consistent with current U.S. federal income tax laws applicable to investment companies such as the Fund, which limit the ability of investment companies to invest directly in Commodity Investments.

The remainder of the Fund’s assets will be invested directly by the Fund, primarily in Fixed-Income Investments, including repurchase agreements, money market instruments, U.S. government and agency securities, Treasury inflation-protected securities, sovereign debt obligations on non-U.S. countries and investment-grade corporate bonds. The Fund invests in Fixed-Income Investments for investment purposes and to provide sufficient assets to account for (or “cover”) mark-to-market changes and to collateralize the Subsidiary’s investments in derivatives.

The Commodity Futures Trading Commission (“CFTC”) has adopted certain requirements that subject registered investment companies and their advisers to regulation by the CFTC if a registered investment company invests more than a prescribed level of its net asset value in CFTC-regulated futures, options and swaps, or if a registered investment company markets itself as providing investment exposure to such instruments. Due to the Fund’s potential use of CFTC-regulated futures, options and swaps above the prescribed levels, it is considered a “commodity pool” under the Commodity Exchange Act (“CEA”).

<b>Summary of Principal Risks </b>

As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is actively managed and is not an index-based ETF.

Asset Class Risk. Securities and other assets in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes (including the futures market).

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

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of the Prospectus), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting.

Carry Strategy Risk. The futures market for a commodity in which the price for a new futures contract is less than the price of an expiring contract, known as a market trading in a state of “backwardation,” may not continue to trade with the same degree of backwardation or with the resulting returns. To the extent that a commodity futures market is not trading in a state of backwardation (or is, but to a lesser degree), the Fund’s cost to maintain exposure to the commodity may increase, the positive carry strategy may prove unsuccessful, and the investment performance of the Fund may suffer.

Cash Management Risk. If a significant amount of the Fund’s assets are invested in cash and cash equivalents, the Fund may underperform other funds that do not similarly invest in cash and cash equivalents for investment purposes and/or to collateralize derivative instruments.

Commodity-Linked Derivatives Risk. The value of a commodity-linked derivative instrument typically is based upon the price movements of the underlying commodity or an economic variable linked to such price movements. Spot prices and futures prices for commodities will vary depending upon expectations regarding market conditions. Both spot and futures prices of commodity-related investments may fluctuate quickly and dramatically as a result of changes affecting a particular commodity and may not correlate to price movements in other asset classes, such as stocks, bonds and cash. Commodity-linked derivatives are subject to the risk that the counterparty to the transaction, the exchange or trading facility on which they trade or the applicable clearing house may default or otherwise fail to perform. In addition, each exchange or trading facility on which the derivatives are traded has the right to suspend or limit trading in all futures or other instruments that it lists. The Fund’s use of commodity-linked derivatives may also have a leveraging effect on the Fund’s portfolio. Leverage generally magnifies the effect of a change in the value of an asset and creates a risk of loss of value on a larger pool of assets than the Fund would otherwise have had. The Fund is required to post margin in respect to its holdings in derivatives. Each of these factors and events could have a significant negative impact on the Fund.

Commodity Regulatory Risk. The Fund and the Subsidiary are deemed commodity pools and BFA is considered a “commodity pool operator” with respect to the Fund under the CEA. BFA is therefore subject to regulation by the SEC and the CFTC. BFA is also subject to regulation by National Futures Association (“NFA”). The regulatory requirements governing the use of commodity futures, options on commodity futures, certain swaps or certain other investments could change at any time.

Commodity Risk. The Fund has substantial exposure to commodities. The Fund invests in instruments and companies that are susceptible to fluctuations in certain commodity markets and to price changes due to trade relations, including the imposition of tariffs by the U.S. and other countries. Any negative changes in commodity markets that may be due to changes in supply and demand for commodities, market events, regulatory developments or other factors that the Fund cannot control could have an adverse impact on those companies.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class.

Counterparty Risk. Certain commodity-linked derivative instruments, uncleared swaps and other forms of financial instruments that involve counterparties subject the Fund to the risk that the counterparty could default on its obligations under the agreement, either through the counterparty’s bankruptcy or failure to perform its obligations. In the event of a counterparty default, the Fund could experience lengthy delays in recovering some or all of its assets or obtain no recovery at all and, if the counterparty is subject to specified types of resolution proceedings, the Fund may be subject to stays that limit its ability to close out positions and limit risk. The Fund’s investments in the futures markets also introduce the risk that its futures commission merchant (“FCM”) could default on an obligation set forth in an agreement between the Fund and the FCM, including the FCM’s obligation to return margin posted in connection with the Fund’s futures contracts.

Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation.

Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers, market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests.

Derivatives Risk. The Fund’s use of derivatives may reduce the Fund’s returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives.

Energy Sector Risk. The market value of securities in the energy sector may decline for many reasons, including, among others, changes in energy prices, energy supply and demand, government regulations and energy conservation efforts.

Futures Contract Risk. Futures are standardized, exchange-traded contracts that obligate a purchaser to take delivery, and a seller to make delivery, of a specific amount of an asset at a specified future date at a specified price. Unlike equities, which typically entitle the holder to a continuing ownership stake in a corporation, futures contracts normally specify a certain date for settlement in cash based on the level of the reference rate. The primary risks associated with the use of futures contracts are: (i) the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; (ii) possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; (iii) losses caused by unanticipated market movements, which are potentially unlimited; (iv) BFA’s inability to predict correctly the direction of prices and other economic factors; and (v) the possibility that the counterparty will default in the performance of its obligations. To the extent that the Fund is exposed to rolling futures contracts, it may be subject to additional risk. In addition, CFTC regulations limit the types of foreign listed futures contracts that U.S. investors, like the Fund, are allowed to invest in. As a result, the Fund may not be able to gain the exposure it seeks through certain non-U.S. futures contracts.

Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices.

Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, or the Fund otherwise needs to purchase additional bonds.

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

Issuer Risk. The performance of the Fund depends on the performance of individual securities or other assets to which the Fund has exposure as well as the correlation among the assets. Changes in the financial condition or credit rating of an issuer of those securities or of securities referenced by swaps or other derivatives or the seller or counterparty with respect to derivatives or other assets may cause the value of the securities, derivatives, or other assets to decline.

Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities or assets selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective.

Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns.

Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

Money Market Instruments Risk. The value of money market instruments may be affected by changing interest rates and by changes in the credit ratings of the investments. If a significant amount of the Fund's assets are invested in money market instruments, it will be more difficult for the Fund to achieve its investment objective. An investment in a money market fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (“FDIC”) or any other government agency. It is possible to lose money by investing in a money market fund. Money market funds other than government money market funds or retail money market funds “float” their NAV instead of using a stable $1.00 per share price.

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

Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Risk of Investing in Agriculture and Livestock. Investments in the agricultural and livestock sectors may be volatile and change unpredictably as a result of many factors, such as legislative or regulatory developments relating to food safety, the imposition of tariffs or other trade restraints, and the supply and demand of each commodity. Increased competition and changes in consumer tastes and spending can also influence the demand for agricultural and livestock products, affecting the price of such commodities and the performance of the Fund.

Risk of Investing in Industrial Metals. The industrial metals sector may be adversely affected by changes in international economic and political conditions, increased competition and changes in industrial and commercial demand for industrial metals. As a result, the price of industrial metals has been subject to substantial price fluctuations over short periods of time.

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

Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses. Certain standardized interest rate and credit default swaps are required to be traded on an exchange or trading platform and centrally cleared. Most other swaps are entered into a negotiated, bi-lateral basis and traded in the over-the-counter market. Swaps are subject to bi-lateral variation margin. Initial margin requirements are in the process of being phased in and should be effective by 2020.

Small Fund Risk. When the Fund’s size is small, the Fund may experience low trading volume and wide bid/ask spreads. In addition, the Fund may face the risk of being delisted if the Fund does not meet certain conditions of the listing exchange.

Subsidiary Risk. In compliance with Subchapter M of the Internal Revenue Code, the Fund may invest up to 25% of its total assets in the Subsidiary. By investing in the Subsidiary, the Fund is indirectly exposed to the risks associated with the Subsidiary’s investments. The Subsidiary is not registered under the 1940 Act, and, unless otherwise noted in this Prospectus, is not subject to the investor protections of the 1940 Act. Changes in the laws of the U.S. and/or the Cayman Islands could result in the inability of the Fund and/or the Subsidiary to operate as described in the Prospectus and the Statement of Additional Information (“SAI”), and could adversely affect the Fund.

Tax Risk. The Fund invests in commodity-linked derivatives indirectly through the Subsidiary because income from these investments, if made directly, might not be treated as “qualifying income” for purposes of the Fund qualifying as a regulated investment company (“RIC”) for U.S. federal income tax purposes. The Fund expects its income with respect to the Subsidiary to be qualifying income. There is a risk that the U.S. Internal Revenue Service (“IRS”) could issue regulations or other guidance holding, or could assert, that the Fund’s income with respect to the Subsidiary will not be considered “qualifying income” for purposes of the Fund remaining qualified as a RIC for U.S. federal income tax purposes. In such circumstances, the Fund may be required to make changes to its operations, which may reduce the Fund’s ability to gain investment exposure to commodities. Fund shareholders may also experience adverse tax consequences in such circumstances.

Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund's valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.

<b>Performance Information </b>

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

[1] The expense information in the table has been restated to reflect current fees.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	iShares U.S. ETF Trust
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
iShares Bloomberg Roll Select Commodity Strategy ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	iSHARES<sup>®</sup> BLOOMBERG ROLL SELECT COMMODITY STRATEGY ETF<br/>Ticker: CMDY                                  Stock Exchange: NYSE Arca
Objective [Heading]	rr_ObjectiveHeading	<b>Investment Objective</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The iShares Bloomberg Roll Select Commodity Strategy ETF (the “Fund”) seeks to provide exposure, on a total return basis, to a diversified group of commodities.
Expense [Heading]	rr_ExpenseHeading	<b>Fees and Expenses</b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities, commodities or other financial instruments and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and any extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”). BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees in an amount equal to the Acquired Fund Fees and Expenses, if any, attributable to investments by the Fund in other funds advised by BFA, or its affiliates, through February 28, 2025. The contractual waiver may be terminated prior to February 28, 2025 only upon written agreement of the Trust and BFA. You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>Annual Fund Operating Expenses<br/>(ongoing expenses that you pay each year as a<br/>percentage of the value of your investments)</b>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	February 28, 2025
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>Portfolio Turnover.</b>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund may pay transaction costs, such as commissions, when it, directly or indirectly through a subsidiary, buys and sells securities or other assets (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. From inception (April 3, 2018) to the most recent fiscal year end, the Fund's portfolio turnover rate was 0% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	none
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Expenses Restated to Reflect Current [Text]	rr_ExpensesRestatedToReflectCurrent	The expense information in the table has been restated to reflect current fees.
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”).
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>Example. </b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>Principal Investment Strategies </b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its investment objective by investing in exchange-traded futures contracts on the Bloomberg Roll Select Commodity Index (the “Index Futures”). The Fund is expected to roll out of existing positions in Index Futures and establish new positions in Index Futures on an ongoing basis. Index Futures subsequently acquired by the Fund may have terms that differ from those of the Index Futures it currently holds and the purchase and sale of these Index Futures may incur transaction fees. In seeking total return, the Fund also seeks to generate interest income and capital appreciation on the cash balances arising from its investment in Index Futures through a cash management strategy consisting of investments in cash and cash equivalents, short-term government obligations and short-term investment-grade fixed-income securities (collectively, “Fixed-Income Investments”). The Fund is an actively managed exchange-traded fund (“ETF”) and does not seek to replicate the performance of a specified index. While the Fund is not an index fund, the Fund’s investment strategy seeks to maximize correlation with the Bloomberg Roll Select Commodity Index (the Bloomberg Benchmark), which is composed of 22 futures contracts across 20 physical agricultural, energy, precious metals and industrial metals commodities. The Bloomberg Benchmark reflects the returns from these commodity futures contracts, and provides broad-based exposure to commodities as an asset class by using liquidity factors and sector caps to avoid over-concentration in any single commodity or commodity sector. In order to maintain exposure to a futures contract on a particular commodity, an investor must sell the position in the expiring contract and buy a new position in a contract with a later delivery month, which is referred to as “rolling.” If the price for the new futures contract is less than the price of the expiring contract, then the market for the commodity is said to be in “backwardation.” In these markets, roll returns are positive, which is referred to as “positive carry.” The term “contango” is used to describe a market in which the price for a new futures contract is more than the price of the expiring contract. In these markets, roll returns are negative, which is referred to as “negative carry.” The Bloomberg Benchmark seeks to employ a positive carry strategy that emphasizes commodities and futures contract months with the greatest degree of backwardation and lowest degree of contango, resulting in net gains through positive roll returns. The Fund will invest in financial instruments providing exposure to commodities and not in the physical commodities themselves. The Fund may also invest in exchange-traded commodity futures contracts similar to those found in the Bloomberg Benchmark, as well as swaps and options on futures that correlate to the investment returns of commodities without investing directly in physical commodities and over-the-counter commodity-linked instruments like commodity-linked notes, swaps and forward contracts (together, the “Commodity Investments”). Investing in derivative contracts may have a leveraging effect on the Fund. Although the Fund may hold the same futures contracts under the same futures rolling schedule as those included in the Bloomberg Benchmark, the Fund is not obligated to invest in any futures contracts included in, and does not seek to replicate the performance of, the Bloomberg Benchmark. The Fund seeks to gain exposure to Index Futures and other Commodity Investments by investing through a wholly-owned subsidiary organized in the Cayman Islands (the “Subsidiary”). The Subsidiary is advised by BFA and has the same investment objective as the Fund. Unlike the Fund, the Subsidiary is not an investment company registered under the Investment Company Act of 1940, as amended (the “1940 Act”). The Subsidiary invests solely in Commodity Investments and cash and cash equivalents. In compliance with Subchapter M of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”), the Fund may invest up to 25% of its total assets in the Subsidiary. The Fund’s Commodity Investments held in the Subsidiary are intended to provide the Fund with exposure to broad commodities consistent with current U.S. federal income tax laws applicable to investment companies such as the Fund, which limit the ability of investment companies to invest directly in Commodity Investments. The remainder of the Fund’s assets will be invested directly by the Fund, primarily in Fixed-Income Investments, including repurchase agreements, money market instruments, U.S. government and agency securities, Treasury inflation-protected securities, sovereign debt obligations on non-U.S. countries and investment-grade corporate bonds. The Fund invests in Fixed-Income Investments for investment purposes and to provide sufficient assets to account for (or “cover”) mark-to-market changes and to collateralize the Subsidiary’s investments in derivatives. The Commodity Futures Trading Commission (“CFTC”) has adopted certain requirements that subject registered investment companies and their advisers to regulation by the CFTC if a registered investment company invests more than a prescribed level of its net asset value in CFTC-regulated futures, options and swaps, or if a registered investment company markets itself as providing investment exposure to such instruments. Due to the Fund’s potential use of CFTC-regulated futures, options and swaps above the prescribed levels, it is considered a “commodity pool” under the Commodity Exchange Act (“CEA”).
Risk [Heading]	rr_RiskHeading	<b>Summary of Principal Risks </b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is actively managed and is not an index-based ETF. Asset Class Risk. Securities and other assets in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes (including the futures market). Assets Under Management (AUM) Risk. From time to time, an Authorized Participant (as defined in the Creations and Redemptions section of the Prospectus), a third-party investor, the Fund’s adviser or an affiliate of the Fund’s adviser, or a fund may invest in the Fund and hold its investment for a specific period of time to allow the Fund to achieve size or scale. There can be no assurance that any such entity would not redeem its investment or that the size of the Fund would be maintained at such levels, which could negatively impact the Fund. Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of the Prospectus), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Carry Strategy Risk. The futures market for a commodity in which the price for a new futures contract is less than the price of an expiring contract, known as a market trading in a state of “backwardation,” may not continue to trade with the same degree of backwardation or with the resulting returns. To the extent that a commodity futures market is not trading in a state of backwardation (or is, but to a lesser degree), the Fund’s cost to maintain exposure to the commodity may increase, the positive carry strategy may prove unsuccessful, and the investment performance of the Fund may suffer. Cash Management Risk. If a significant amount of the Fund’s assets are invested in cash and cash equivalents, the Fund may underperform other funds that do not similarly invest in cash and cash equivalents for investment purposes and/or to collateralize derivative instruments. Commodity-Linked Derivatives Risk. The value of a commodity-linked derivative instrument typically is based upon the price movements of the underlying commodity or an economic variable linked to such price movements. Spot prices and futures prices for commodities will vary depending upon expectations regarding market conditions. Both spot and futures prices of commodity-related investments may fluctuate quickly and dramatically as a result of changes affecting a particular commodity and may not correlate to price movements in other asset classes, such as stocks, bonds and cash. Commodity-linked derivatives are subject to the risk that the counterparty to the transaction, the exchange or trading facility on which they trade or the applicable clearing house may default or otherwise fail to perform. In addition, each exchange or trading facility on which the derivatives are traded has the right to suspend or limit trading in all futures or other instruments that it lists. The Fund’s use of commodity-linked derivatives may also have a leveraging effect on the Fund’s portfolio. Leverage generally magnifies the effect of a change in the value of an asset and creates a risk of loss of value on a larger pool of assets than the Fund would otherwise have had. The Fund is required to post margin in respect to its holdings in derivatives. Each of these factors and events could have a significant negative impact on the Fund. Commodity Regulatory Risk. The Fund and the Subsidiary are deemed commodity pools and BFA is considered a “commodity pool operator” with respect to the Fund under the CEA. BFA is therefore subject to regulation by the SEC and the CFTC. BFA is also subject to regulation by National Futures Association (“NFA”). The regulatory requirements governing the use of commodity futures, options on commodity futures, certain swaps or certain other investments could change at any time. Commodity Risk. The Fund has substantial exposure to commodities. The Fund invests in instruments and companies that are susceptible to fluctuations in certain commodity markets and to price changes due to trade relations, including the imposition of tariffs by the U.S. and other countries. Any negative changes in commodity markets that may be due to changes in supply and demand for commodities, market events, regulatory developments or other factors that the Fund cannot control could have an adverse impact on those companies. Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. Counterparty Risk. Certain commodity-linked derivative instruments, uncleared swaps and other forms of financial instruments that involve counterparties subject the Fund to the risk that the counterparty could default on its obligations under the agreement, either through the counterparty’s bankruptcy or failure to perform its obligations. In the event of a counterparty default, the Fund could experience lengthy delays in recovering some or all of its assets or obtain no recovery at all and, if the counterparty is subject to specified types of resolution proceedings, the Fund may be subject to stays that limit its ability to close out positions and limit risk. The Fund’s investments in the futures markets also introduce the risk that its futures commission merchant (“FCM”) could default on an obligation set forth in an agreement between the Fund and the FCM, including the FCM’s obligation to return margin posted in connection with the Fund’s futures contracts. Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation. Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers, market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests. Derivatives Risk. The Fund’s use of derivatives may reduce the Fund’s returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives. Energy Sector Risk. The market value of securities in the energy sector may decline for many reasons, including, among others, changes in energy prices, energy supply and demand, government regulations and energy conservation efforts. Futures Contract Risk. Futures are standardized, exchange-traded contracts that obligate a purchaser to take delivery, and a seller to make delivery, of a specific amount of an asset at a specified future date at a specified price. Unlike equities, which typically entitle the holder to a continuing ownership stake in a corporation, futures contracts normally specify a certain date for settlement in cash based on the level of the reference rate. The primary risks associated with the use of futures contracts are: (i) the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; (ii) possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; (iii) losses caused by unanticipated market movements, which are potentially unlimited; (iv) BFA’s inability to predict correctly the direction of prices and other economic factors; and (v) the possibility that the counterparty will default in the performance of its obligations. To the extent that the Fund is exposed to rolling futures contracts, it may be subject to additional risk. In addition, CFTC regulations limit the types of foreign listed futures contracts that U.S. investors, like the Fund, are allowed to invest in. As a result, the Fund may not be able to gain the exposure it seeks through certain non-U.S. futures contracts. Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, or the Fund otherwise needs to purchase additional bonds. Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. Issuer Risk. The performance of the Fund depends on the performance of individual securities or other assets to which the Fund has exposure as well as the correlation among the assets. Changes in the financial condition or credit rating of an issuer of those securities or of securities referenced by swaps or other derivatives or the seller or counterparty with respect to derivatives or other assets may cause the value of the securities, derivatives, or other assets to decline. Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities or assets selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. Money Market Instruments Risk. The value of money market instruments may be affected by changing interest rates and by changes in the credit ratings of the investments. If a significant amount of the Fund's assets are invested in money market instruments, it will be more difficult for the Fund to achieve its investment objective. An investment in a money market fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (“FDIC”) or any other government agency. It is possible to lose money by investing in a money market fund. Money market funds other than government money market funds or retail money market funds “float” their NAV instead of using a stable $1.00 per share price. Non-Diversification Risk. The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers or in derivatives with a limited number of counterparties. As a result, the Fund's performance may depend on the performance of a small number of issuers and counterparties. Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks. Risk of Investing in Agriculture and Livestock. Investments in the agricultural and livestock sectors may be volatile and change unpredictably as a result of many factors, such as legislative or regulatory developments relating to food safety, the imposition of tariffs or other trade restraints, and the supply and demand of each commodity. Increased competition and changes in consumer tastes and spending can also influence the demand for agricultural and livestock products, affecting the price of such commodities and the performance of the Fund. Risk of Investing in Industrial Metals. The industrial metals sector may be adversely affected by changes in international economic and political conditions, increased competition and changes in industrial and commercial demand for industrial metals. As a result, the price of industrial metals has been subject to substantial price fluctuations over short periods of time. Risk of Investing in the U.S. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure. Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses. Certain standardized interest rate and credit default swaps are required to be traded on an exchange or trading platform and centrally cleared. Most other swaps are entered into a negotiated, bi-lateral basis and traded in the over-the-counter market. Swaps are subject to bi-lateral variation margin. Initial margin requirements are in the process of being phased in and should be effective by 2020. Small Fund Risk. When the Fund’s size is small, the Fund may experience low trading volume and wide bid/ask spreads. In addition, the Fund may face the risk of being delisted if the Fund does not meet certain conditions of the listing exchange. Subsidiary Risk. In compliance with Subchapter M of the Internal Revenue Code, the Fund may invest up to 25% of its total assets in the Subsidiary. By investing in the Subsidiary, the Fund is indirectly exposed to the risks associated with the Subsidiary’s investments. The Subsidiary is not registered under the 1940 Act, and, unless otherwise noted in this Prospectus, is not subject to the investor protections of the 1940 Act. Changes in the laws of the U.S. and/or the Cayman Islands could result in the inability of the Fund and/or the Subsidiary to operate as described in the Prospectus and the Statement of Additional Information (“SAI”), and could adversely affect the Fund. Tax Risk. The Fund invests in commodity-linked derivatives indirectly through the Subsidiary because income from these investments, if made directly, might not be treated as “qualifying income” for purposes of the Fund qualifying as a regulated investment company (“RIC”) for U.S. federal income tax purposes. The Fund expects its income with respect to the Subsidiary to be qualifying income. There is a risk that the U.S. Internal Revenue Service (“IRS”) could issue regulations or other guidance holding, or could assert, that the Fund’s income with respect to the Subsidiary will not be considered “qualifying income” for purposes of the Fund remaining qualified as a RIC for U.S. federal income tax purposes. In such circumstances, the Fund may be required to make changes to its operations, which may reduce the Fund’s ability to gain investment exposure to commodities. Fund shareholders may also experience adverse tax consequences in such circumstances. Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund's valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	<b>Non-Diversification Risk.</b> The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers or in derivatives with a limited number of counterparties. As a result, the Fund's performance may depend on the performance of a small number of issuers and counterparties.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>Performance Information </b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	As of the date of the Prospectus, the Fund has been in operation for less than one full calendar year and therefore does not report its performance information.
Performance One Year or Less [Text]	rr_PerformanceOneYearOrLess	As of the date of the Prospectus, the Fund has been in operation for less than one full calendar year and therefore does not report its performance information.
iShares Bloomberg Roll Select Commodity Strategy ETF | iShares Bloomberg Roll Select Commodity Strategy ETF
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.28%	[1]
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none	[1]
Other Expenses	rr_OtherExpensesOverAssets	none	[1]
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.29%	[1]
Fee Waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.01%)	[1]
Total Annual Fund Operating Expenses After Fee Waiver	rr_NetExpensesOverAssets	0.28%	[1]
1 Year	rr_ExpenseExampleYear01	$ 29
3 Years	rr_ExpenseExampleYear03	90
5 Years	rr_ExpenseExampleYear05	157
10 Years	rr_ExpenseExampleYear10	$ 362

[1] The expense information in the table has been restated to reflect current fees.

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iShares Commodities Select Strategy ETF

iSHARES^® COMMODITIES SELECT STRATEGY ETF<br/>Ticker: COMT                                 Stock Exchange: NASDAQ

<b>Investment Objective</b>

The iShares Commodities Select Strategy ETF (the “Fund”) seeks total return by providing investors with broad commodity exposure.

<b>Fees and Expenses</b>

The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities, commodities or other financial instruments and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and any extraordinary expenses and are not included in the calculation of the ratio of expenses to average net assets shown in the Consolidated Financial Highlights section of this prospectus (the “Prospectus”). The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Prospectus. BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees in an amount equal to the Acquired Fund Fees and Expenses, if any, attributable to investments by the Fund in other registered investment companies advised by BFA, or its affiliates, through February 29, 2024. The contractual waiver may be terminated prior to February 29, 2024 only upon written agreement of the Trust and BFA.

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

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

Annual Fund Operating Expenses	Management Fees	Distribution and Service (12b-1) Fees	Other Expenses		Acquired Fund Fees and Expenses		Total Annual Fund Operating Expenses	Fee Waiver	Total Annual Fund Operating Expenses After Fee Waiver
iShares Commodities Select Strategy ETF | iShares Commodities Select Strategy ETF	0.48%	none	none	[1]	none	[1]	0.48%	none	0.48%

<b>Example. </b>

This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example	1 Year	3 Years	5 Years	10 Years
iShares Commodities Select Strategy ETF | iShares Commodities Select Strategy ETF | USD ($)	49	154	269	604

<b>Portfolio Turnover.</b>

The Fund may pay transaction costs, such as commissions, when it, directly or through a subsidiary, buys and sells securities or other assets (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 167% of the average value of its portfolio.

<b>Principal Investment Strategies </b>

The Fund seeks to achieve its investment objective by investing in a combination of exchange-traded commodity futures contracts, exchange-traded options on commodity-related futures contracts and exchange-cleared commodity-related swaps (together, “Commodity-Linked Investments”) and equity securities of issuers engaged in a commodities-related business (“Commodity-Related Equities”), thereby obtaining exposure to the commodities markets. The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index.

Commodity-Linked Investments include, but are not limited to, futures contracts in the S&P GSCI^TM Dynamic Roll Reduced Energy 70/30 Futures/Equity Blend (the “S&P Blended Benchmark”), such as aluminum, Brent crude oil, cocoa, coffee, copper, corn, cotton, gas oil, feeder cattle, gold, heating oil, lean hogs, lead, live cattle, natural gas, nickel, orange juice, silver, soybeans, sugar, unleaded gasoline, wheat, West Texas Intermediate crude oil and zinc. Commodity-Linked Investments may also include exchange-cleared swaps on commodities and exchange-traded options on futures that provide exposure to the investment returns of the commodities markets, without investing directly in physical commodities. Investing in Commodity-Linked Investments may have a leveraging effect on the Fund.

Commodity-Related Equities include, but are not limited to, exchange-listed equities in the S&P Blended Benchmark, such as those involved in production or services related to agriculture, livestock, industrial and precious metals, or coal, gas, and oil.

Although the Fund generally holds, among other investments, the same futures contracts and equities as the S&P Blended Benchmark, the Fund is not obligated to invest in such futures contracts and equities and does not seek to track the performance of the S&P Blended Benchmark. The S&P Blended Benchmark is an unmanaged index.

The Fund will invest directly in Commodity-Related Equities of U.S. and non-U.S. issuers and will seek to gain exposure to Commodity-Linked Investments by investing through a wholly-owned subsidiary organized in the Cayman Islands (the “Subsidiary”). The Subsidiary is advised by BFA and has the same investment objective as the Fund. Unlike the Fund, the Subsidiary is not an investment company registered under the Investment Company Act of 1940, as amended (the “1940 Act”). The Subsidiary will invest solely in Commodity-Linked Investments and cash.

In compliance with Subchapter M of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”), the Fund may invest up to 25% of its total assets in the Subsidiary. The Fund’s Commodity-Linked Investments held in the Subsidiary are intended to provide the Fund with exposure to commodity markets within the limits of current U.S. federal income tax laws applicable to investment companies such as the Fund, which limit the ability of investment companies to invest directly in Commodity-Linked Investments.

The remainder of the Fund’s assets will be invested directly by the Fund, primarily in cash and cash equivalents, short-term investment-grade fixed-income securities that include U.S. government and agency securities, Treasury inflation-protected securities, sovereign debt obligations of non-U.S. countries, repurchase agreements and money market instruments. The Fund uses such instruments as investments and to provide sufficient assets to account for (or “cover”) mark-to-market changes and to collateralize the Subsidiary’s Commodity-Linked Investments exposure on a day-to-day basis.

The Fund or the Subsidiary may from time to time invest in other ETFs, exchange-traded notes or commodity-linked notes.

The Commodity Futures Trading Commission (“CFTC”) has adopted certain requirements that subject registered investment companies and their advisers to regulation by the CFTC if a registered investment company invests more than a prescribed level of its net asset value in CFTC-regulated futures, options and swaps, or if a registered investment company markets itself as providing investment exposure to such instruments. Due to the Fund's potential use of CFTC-regulated futures, options and swaps above the prescribed levels, it is considered a “commodity pool” under the Commodity Exchange Act (“CEA”).

The Fund may lend securities representing up to one-third of the value of the Fund's total assets (including the value of the collateral received).

Industry Concentration Policy. The Fund will concentrate its investments (i.e., hold 25% or more of its total assets) in (i) equity securities issued by commodity-related companies, derivatives with exposure to commodity-related companies or investments in securities and derivatives linked to the underlying price movement of commodities, including but not limited to commodity-linked derivatives such as commodity-linked notes, commodity futures, forward contracts and swaps and other similar derivative instruments and investment vehicles that invest in commodities, or commodity-linked derivatives, and (ii) the industry or group of industries that constitutes the energy sector. 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.

<b>Summary of Principal Risks </b>

As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below (either directly or through its investments in the Subsidiary), any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is actively managed and is not an index-based ETF.

Asset Class Risk. Securities and other assets in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes (including the futures market).

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of this prospectus (“the Prospectus”)), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes.

Cash Management Risk. If a significant amount of the Fund’s assets are invested in cash and cash equivalents, the Fund may underperform other funds that do not similarly invest in cash and cash equivalents for investment purposes and/or to collateralize derivative instruments.

Commodity-Linked Derivatives Risk. The value of a commodity-linked derivative instrument typically is based upon the price movements of the underlying commodity or an economic variable linked to such price movements. The prices of commodity-related investments may fluctuate quickly and dramatically as a result of changes affecting a particular commodity and may not correlate to price movements in other asset classes, such as stocks, bonds and cash. Commodity-linked derivatives are subject to the risk that the counterparty to the transaction, the exchange or trading facility on which they trade or the applicable clearing house may default or otherwise fail to perform. In addition, each exchange or trading facility on which the derivatives are traded has the right to suspend or limit trading in all futures or other instruments that it lists. The Fund’s use of commodity-linked derivatives may also have a leveraging effect on the Fund’s portfolio. Leverage generally magnifies the effect of a change in the value of an asset and creates a risk of loss of value on a larger pool of assets than the Fund would otherwise have had. The Fund is required to post margin in respect to its holdings in derivatives. Each of these factors and events could have a significant negative impact on the Fund.

Commodity Regulatory Risk. The Fund and the Subsidiary are deemed commodity pools and BFA is considered a “commodity pool operator” with respect to the Fund under the CEA. BFA is therefore subject to regulation by the SEC and the CFTC. BFA is also subject to regulation by National Futures Association (“NFA”). The regulatory requirements governing the use of commodity futures, options on commodity futures, certain swaps or certain other investments could change at any time.

Commodity Risk. The Fund invests in instruments and companies that are susceptible to fluctuations in certain commodity markets and to price changes due to trade relations, including the imposition of tariffs by the U.S. and other importing countries. Any negative changes in commodity markets that may be due to changes in supply and demand for commodities, market events, regulatory developments or other factors that the Fund cannot control could have an adverse impact on those companies.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class.

Counterparty Risk. Certain commodity-linked derivative instruments, uncleared swaps and other forms of financial instruments that involve counterparties subject the Fund to the risk that the counterparty could default on its obligations under the agreement, either through the counterparty’s bankruptcy or failure to perform its obligations. In the event of a counterparty default, the Fund could experience lengthy delays in recovering some or all of its assets or obtain no recovery at all and, if the counterparty is subject to specified types of resolution proceedings, the Fund may be subject to stays that limit its ability to close out positions and limit risk. The Fund’s investments in the futures markets also introduce the risk that its futures commission merchant (“FCM”) could default on an obligation set forth in an agreement between the Fund and the FCM, including the FCM’s obligation to return margin posted in connection with the Fund’s futures contracts.

Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation.

Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers (including the benchmark provider), market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests.

Derivatives Risk. The Fund’s use of derivatives may reduce the Fund’s returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives.

Dividend Risk. There is no guarantee that issuers of the stocks held by the Fund will declare dividends in the future or that, if declared, they will either remain at current levels or increase over time.

Energy Sector Risk. The market value of securities in the energy sector may decline for many reasons, including, among others, changes in energy prices, energy supply and demand, government regulations and energy conservation efforts.

Equity Securities Risk. Equity securities are subject to changes in value, and their values may be more volatile than those of other asset classes. Holders of common stocks, which generally subject their holders to more risks than preferred stocks and debt securities because common stockholders’ claims are subordinated to those of holders of preferred stocks and debt securities upon the bankruptcy of the issuer.

Futures Contract Risk. Futures are standardized, exchange-traded contracts that obligate a purchaser to take delivery, and a seller to make delivery, of a specific amount of an asset at a specified future date at a specified price. Unlike equities, which typically entitle the holder to a continuing ownership stake in a corporation, futures contracts normally specify a certain date for settlement in cash based on the level of the reference rate. The primary risks associated with the use of futures contracts, or swaps or other derivatives referencing futures contracts, are: (i) the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; (ii) possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; (iii) losses caused by unanticipated market movements, which are potentially unlimited; (iv) BFA’s inability to predict correctly the direction of prices and other economic factors; and (v) the possibility that the counterparty will default in the performance of its obligations. To the extent that the Fund is exposed to rolling futures contracts, it may be subject to additional risk. In addition, CFTC regulations limit the types of foreign listed futures contracts that U.S. investors, like the Fund, are allowed to invest in. As a result, the Fund may not be able to gain the exposure it seeks through certain non-U.S. futures contracts.

Geographic Risk. A natural disaster could occur in a geographic region in which the Fund invests, which could adversely affect the economy or the business operations of companies in the specific geographic region, causing an adverse impact on the Fund's investments in the affected region.

Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices.

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

Issuer Risk. The performance of the Fund depends on the performance of individual securities or other assets to which the Fund has exposure as well as the correlation among the assets. Changes in the financial condition or credit rating of an issuer of those securities or of securities referenced by swaps or other derivatives or the seller or counterparty with respect to derivatives or other assets may cause the value of the securities, derivatives, to decline.

Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA and BlackRock International Limited (“BIL”), the Fund's sub-adviser, will not produce the desired results, and that securities or assets selected by BFA and BIL may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA and BIL in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective.

Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns.

Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

Metals and Mining Industry Risk. Companies in the metals and mining industry are susceptible to fluctuations in worldwide metal prices and extraction and production costs. In addition, metals and mining companies may have significant operations in areas at risk for social and political unrest, security concerns and environmental damage. These companies may also be at risk for increased government regulation and intervention. Such risks may adversely affect the issuers to which the Fund has exposure.

Money Market Instruments Risk. The value of money market instruments may be affected by changing interest rates and by changes in the credit ratings of the investments. If a significant amount of the Fund's assets are invested in money market instruments, it will be more difficult for the Fund to achieve its investment objective. An investment in a money market fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (“FDIC”) or any other government agency. It is possible to lose money by investing in a money market fund. Money market funds other than government money market funds or retail money market funds “float” their NAV instead of using a stable $1.00 per share price.

National Closed Market Trading Risk. To the extent that the underlying securities held by the Fund trade on foreign exchanges or in foreign markets that may be closed when the securities exchange on which the Fund’s shares trade is open, there are likely to be deviations between the current price of such an underlying security and the last quoted price for the underlying security (i.e., the Fund’s quote from the closed foreign market). These deviations could result in premiums or discounts to the Fund’s NAV that may be greater than those experienced by other ETFs.

Non-U.S. Securities Risk. Investments in the securities of non-U.S. issuers are subject to the risks associated with investing in those non-U.S. markets, such as heightened risks of inflation or nationalization. The Fund may lose money due to political, economic and geographic events affecting issuers of non-U.S. securities or non-U.S. markets. In addition, non-U.S. securities markets may trade a small number of securities and may be unable to respond effectively to changes in trading volume, potentially making prompt liquidation of holdings difficult or impossible at times.

Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Reliance on Trading Partners Risk. The Fund invests in countries or regions whose economies are heavily dependent upon trading with key partners. Any reduction in this trading may have an adverse impact on the Fund's investments. Through its holdings of securities of certain issuers, the Fund is specifically exposed to North American Economic Risk.

Risk of Investing in Agriculture and Livestock. Investments in the agricultural and livestock sectors may be volatile and change unpredictably as a result of many factors, such as legislative or regulatory developments relating to food safety, the imposition of tariffs or other trade restraints, and the supply and demand of each commodity. Increased competition and changes in consumer tastes and spending can also influence the demand for agricultural and livestock products, affecting the price of such commodities and the performance of the Fund.

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

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

Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses. Certain standardized interest rate and credit default swaps are required to be traded on an exchange or trading platform and centrally cleared. Most other swaps are entered into a negotiated, bi-lateral basis and traded in the over-the-counter market. Swaps are subject to bi-lateral variation margin. Initial margin requirements are in the process of being phased in and should be effective by 2020.

Securities Lending Risk. The Fund may engage in securities lending. Securities lending involves the risk that the Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund.

Subsidiary Risk. In compliance with Subchapter M of the Internal Revenue Code, the Fund may invest up to 25% of its total assets in the Subsidiary. By investing in the Subsidiary, the Fund is indirectly exposed to the risks associated with the Subsidiary’s investments. The Subsidiary is not registered under the 1940 Act, and, unless otherwise noted in this Prospectus, is not subject to the investor protections of the 1940 Act. Changes in the laws of the U.S. and/or the Cayman Islands could result in the inability of the Fund and/or the Subsidiary to operate as described in the Prospectus and the Statement of Additional Information (“SAI”), and could adversely affect the Fund.

Tax Risk. The Fund invests in commodity-linked derivatives indirectly through the Subsidiary because income from these investments, if made directly, might not be treated as “qualifying income” for purposes of the Fund qualifying as a regulated investment company (“RIC”) for U.S. federal income tax purposes. The Fund expects its income with respect to the Subsidiary to be qualifying income. There is a risk that the U.S. Internal Revenue Service (“IRS”) could issue regulations or other guidance holding, or could assert, that the Fund’s income with respect to the Subsidiary will not be considered “qualifying income” for purposes of the Fund remaining qualified as a RIC for U.S. federal income tax purposes. In such circumstances, the Fund may be required to make changes to its operations, which may reduce the Fund’s ability to gain investment exposure to commodities. Fund shareholders may also experience adverse tax consequences in such circumstances.

Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund's valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.

<b>Performance Information </b>

The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.

<b>Year by Year Returns (Years Ended December 31)</b>

The best calendar quarter return during the periods shown above was 13.13% in the 2nd quarter of 2016; the worst was -18.08% in the 3rd quarter of 2015.

Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).

<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>

Average Annual Total Returns - iShares Commodities Select Strategy ETF		One Year	Since Fund Inception	Inception Date
iShares Commodities Select Strategy ETF		(6.60%)	(7.17%)	Oct. 15, 2014
iShares Commodities Select Strategy ETF | Return After Taxes on Distributions	[1]	(10.34%)	(8.67%)
iShares Commodities Select Strategy ETF | Return After Taxes on Distributions and Sale of Fund Shares	[1]	(3.68%)	(5.81%)
S&P GSCI™ Commodity Total Return Index (Index returns do not reflect deductions for fees, expenses, or taxes)	[2],[3]	(13.82%)	(13.99%)
S&P GSCI™ Dynamic Roll Reduced Energy 70/30 Futures/Equity Blend (Index returns do not reflect deductions for fees, expenses, or taxes)	[3]	(4.91%)	(11.96%)

[1] For the most recently completed fiscal year, the amount rounded to 0.00%.

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[2] The S&P GSCI™ Commodity Total Return Index, the Fund's performance benchmark, is an unmanaged index that measures the performance of general commodity price movements and inflation in the world economy.

[3] The S&P GSCI™ Dynamic Roll Reduced Energy 70/30 Futures/Equity Blend is an unmanaged index that is designed to measure the performance of a multi-asset allocation strategy that consists of a futures-based commodities index and an equity-based index that is based on various commodity-related GICS subsectors.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	iShares U.S. ETF Trust
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
iShares Commodities Select Strategy ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	iSHARES<sup>®</sup> COMMODITIES SELECT STRATEGY ETF<br/>Ticker: COMT                                 Stock Exchange: NASDAQ
Objective [Heading]	rr_ObjectiveHeading	<b>Investment Objective</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The iShares Commodities Select Strategy ETF (the “Fund”) seeks total return by providing investors with broad commodity exposure.
Expense [Heading]	rr_ExpenseHeading	<b>Fees and Expenses</b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities, commodities or other financial instruments and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and any extraordinary expenses and are not included in the calculation of the ratio of expenses to average net assets shown in the Consolidated Financial Highlights section of this prospectus (the “Prospectus”). The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Prospectus. BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees in an amount equal to the Acquired Fund Fees and Expenses, if any, attributable to investments by the Fund in other registered investment companies advised by BFA, or its affiliates, through February 29, 2024. The contractual waiver may be terminated prior to February 29, 2024 only upon written agreement of the Trust and BFA. You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>Annual Fund Operating Expenses<br/>(ongoing expenses that you pay each year as a<br/>percentage of the value of your investments)</b>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	February 29, 2024
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>Portfolio Turnover.</b>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund may pay transaction costs, such as commissions, when it, directly or through a subsidiary, buys and sells securities or other assets (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 167% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	167.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Prospectus.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>Example. </b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>Principal Investment Strategies </b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its investment objective by investing in a combination of exchange-traded commodity futures contracts, exchange-traded options on commodity-related futures contracts and exchange-cleared commodity-related swaps (together, “Commodity-Linked Investments”) and equity securities of issuers engaged in a commodities-related business (“Commodity-Related Equities”), thereby obtaining exposure to the commodities markets. The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index. Commodity-Linked Investments include, but are not limited to, futures contracts in the S&P GSCITM Dynamic Roll Reduced Energy 70/30 Futures/Equity Blend (the “S&P Blended Benchmark”), such as aluminum, Brent crude oil, cocoa, coffee, copper, corn, cotton, gas oil, feeder cattle, gold, heating oil, lean hogs, lead, live cattle, natural gas, nickel, orange juice, silver, soybeans, sugar, unleaded gasoline, wheat, West Texas Intermediate crude oil and zinc. Commodity-Linked Investments may also include exchange-cleared swaps on commodities and exchange-traded options on futures that provide exposure to the investment returns of the commodities markets, without investing directly in physical commodities. Investing in Commodity-Linked Investments may have a leveraging effect on the Fund. Commodity-Related Equities include, but are not limited to, exchange-listed equities in the S&P Blended Benchmark, such as those involved in production or services related to agriculture, livestock, industrial and precious metals, or coal, gas, and oil. Although the Fund generally holds, among other investments, the same futures contracts and equities as the S&P Blended Benchmark, the Fund is not obligated to invest in such futures contracts and equities and does not seek to track the performance of the S&P Blended Benchmark. The S&P Blended Benchmark is an unmanaged index. The Fund will invest directly in Commodity-Related Equities of U.S. and non-U.S. issuers and will seek to gain exposure to Commodity-Linked Investments by investing through a wholly-owned subsidiary organized in the Cayman Islands (the “Subsidiary”). The Subsidiary is advised by BFA and has the same investment objective as the Fund. Unlike the Fund, the Subsidiary is not an investment company registered under the Investment Company Act of 1940, as amended (the “1940 Act”). The Subsidiary will invest solely in Commodity-Linked Investments and cash. In compliance with Subchapter M of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”), the Fund may invest up to 25% of its total assets in the Subsidiary. The Fund’s Commodity-Linked Investments held in the Subsidiary are intended to provide the Fund with exposure to commodity markets within the limits of current U.S. federal income tax laws applicable to investment companies such as the Fund, which limit the ability of investment companies to invest directly in Commodity-Linked Investments. The remainder of the Fund’s assets will be invested directly by the Fund, primarily in cash and cash equivalents, short-term investment-grade fixed-income securities that include U.S. government and agency securities, Treasury inflation-protected securities, sovereign debt obligations of non-U.S. countries, repurchase agreements and money market instruments. The Fund uses such instruments as investments and to provide sufficient assets to account for (or “cover”) mark-to-market changes and to collateralize the Subsidiary’s Commodity-Linked Investments exposure on a day-to-day basis. The Fund or the Subsidiary may from time to time invest in other ETFs, exchange-traded notes or commodity-linked notes. The Commodity Futures Trading Commission (“CFTC”) has adopted certain requirements that subject registered investment companies and their advisers to regulation by the CFTC if a registered investment company invests more than a prescribed level of its net asset value in CFTC-regulated futures, options and swaps, or if a registered investment company markets itself as providing investment exposure to such instruments. Due to the Fund's potential use of CFTC-regulated futures, options and swaps above the prescribed levels, it is considered a “commodity pool” under the Commodity Exchange Act (“CEA”). The Fund may lend securities representing up to one-third of the value of the Fund's total assets (including the value of the collateral received). Industry Concentration Policy. The Fund will concentrate its investments (i.e., hold 25% or more of its total assets) in (i) equity securities issued by commodity-related companies, derivatives with exposure to commodity-related companies or investments in securities and derivatives linked to the underlying price movement of commodities, including but not limited to commodity-linked derivatives such as commodity-linked notes, commodity futures, forward contracts and swaps and other similar derivative instruments and investment vehicles that invest in commodities, or commodity-linked derivatives, and (ii) the industry or group of industries that constitutes the energy sector. For purposes of this limitation, securities of the U.S. government (including its agencies and instrumentalities), repurchase agreements collateralized by U.S. government securities, and securities of state or municipal governments and their political subdivisions are not considered to be issued by members of any industry.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<b>Industry Concentration Policy.</b> The Fund will concentrate its investments (i.e., hold 25% or more of its total assets) in (i) equity securities issued by commodity-related companies, derivatives with exposure to commodity-related companies or investments in securities and derivatives linked to the underlying price movement of commodities, including but not limited to commodity-linked derivatives such as commodity-linked notes, commodity futures, forward contracts and swaps and other similar derivative instruments and investment vehicles that invest in commodities, or commodity-linked derivatives, and (ii) the industry or group of industries that constitutes the energy sector. For purposes of this limitation, securities of the U.S. government (including its agencies and instrumentalities), repurchase agreements collateralized by U.S. government securities, and securities of state or municipal governments and their political subdivisions are not considered to be issued by members of any industry.
Risk [Heading]	rr_RiskHeading	<b>Summary of Principal Risks </b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below (either directly or through its investments in the Subsidiary), any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is actively managed and is not an index-based ETF. Asset Class Risk. Securities and other assets in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes (including the futures market). Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of this prospectus (“the Prospectus”)), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes. Cash Management Risk. If a significant amount of the Fund’s assets are invested in cash and cash equivalents, the Fund may underperform other funds that do not similarly invest in cash and cash equivalents for investment purposes and/or to collateralize derivative instruments. Commodity-Linked Derivatives Risk. The value of a commodity-linked derivative instrument typically is based upon the price movements of the underlying commodity or an economic variable linked to such price movements. The prices of commodity-related investments may fluctuate quickly and dramatically as a result of changes affecting a particular commodity and may not correlate to price movements in other asset classes, such as stocks, bonds and cash. Commodity-linked derivatives are subject to the risk that the counterparty to the transaction, the exchange or trading facility on which they trade or the applicable clearing house may default or otherwise fail to perform. In addition, each exchange or trading facility on which the derivatives are traded has the right to suspend or limit trading in all futures or other instruments that it lists. The Fund’s use of commodity-linked derivatives may also have a leveraging effect on the Fund’s portfolio. Leverage generally magnifies the effect of a change in the value of an asset and creates a risk of loss of value on a larger pool of assets than the Fund would otherwise have had. The Fund is required to post margin in respect to its holdings in derivatives. Each of these factors and events could have a significant negative impact on the Fund. Commodity Regulatory Risk. The Fund and the Subsidiary are deemed commodity pools and BFA is considered a “commodity pool operator” with respect to the Fund under the CEA. BFA is therefore subject to regulation by the SEC and the CFTC. BFA is also subject to regulation by National Futures Association (“NFA”). The regulatory requirements governing the use of commodity futures, options on commodity futures, certain swaps or certain other investments could change at any time. Commodity Risk. The Fund invests in instruments and companies that are susceptible to fluctuations in certain commodity markets and to price changes due to trade relations, including the imposition of tariffs by the U.S. and other importing countries. Any negative changes in commodity markets that may be due to changes in supply and demand for commodities, market events, regulatory developments or other factors that the Fund cannot control could have an adverse impact on those companies. Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. Counterparty Risk. Certain commodity-linked derivative instruments, uncleared swaps and other forms of financial instruments that involve counterparties subject the Fund to the risk that the counterparty could default on its obligations under the agreement, either through the counterparty’s bankruptcy or failure to perform its obligations. In the event of a counterparty default, the Fund could experience lengthy delays in recovering some or all of its assets or obtain no recovery at all and, if the counterparty is subject to specified types of resolution proceedings, the Fund may be subject to stays that limit its ability to close out positions and limit risk. The Fund’s investments in the futures markets also introduce the risk that its futures commission merchant (“FCM”) could default on an obligation set forth in an agreement between the Fund and the FCM, including the FCM’s obligation to return margin posted in connection with the Fund’s futures contracts. Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation. Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers (including the benchmark provider), market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests. Derivatives Risk. The Fund’s use of derivatives may reduce the Fund’s returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives. Dividend Risk. There is no guarantee that issuers of the stocks held by the Fund will declare dividends in the future or that, if declared, they will either remain at current levels or increase over time. Energy Sector Risk. The market value of securities in the energy sector may decline for many reasons, including, among others, changes in energy prices, energy supply and demand, government regulations and energy conservation efforts. Equity Securities Risk. Equity securities are subject to changes in value, and their values may be more volatile than those of other asset classes. Holders of common stocks, which generally subject their holders to more risks than preferred stocks and debt securities because common stockholders’ claims are subordinated to those of holders of preferred stocks and debt securities upon the bankruptcy of the issuer. Futures Contract Risk. Futures are standardized, exchange-traded contracts that obligate a purchaser to take delivery, and a seller to make delivery, of a specific amount of an asset at a specified future date at a specified price. Unlike equities, which typically entitle the holder to a continuing ownership stake in a corporation, futures contracts normally specify a certain date for settlement in cash based on the level of the reference rate. The primary risks associated with the use of futures contracts, or swaps or other derivatives referencing futures contracts, are: (i) the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; (ii) possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; (iii) losses caused by unanticipated market movements, which are potentially unlimited; (iv) BFA’s inability to predict correctly the direction of prices and other economic factors; and (v) the possibility that the counterparty will default in the performance of its obligations. To the extent that the Fund is exposed to rolling futures contracts, it may be subject to additional risk. In addition, CFTC regulations limit the types of foreign listed futures contracts that U.S. investors, like the Fund, are allowed to invest in. As a result, the Fund may not be able to gain the exposure it seeks through certain non-U.S. futures contracts. Geographic Risk. A natural disaster could occur in a geographic region in which the Fund invests, which could adversely affect the economy or the business operations of companies in the specific geographic region, causing an adverse impact on the Fund's investments in the affected region. Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. Issuer Risk. The performance of the Fund depends on the performance of individual securities or other assets to which the Fund has exposure as well as the correlation among the assets. Changes in the financial condition or credit rating of an issuer of those securities or of securities referenced by swaps or other derivatives or the seller or counterparty with respect to derivatives or other assets may cause the value of the securities, derivatives, to decline. Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA and BlackRock International Limited (“BIL”), the Fund's sub-adviser, will not produce the desired results, and that securities or assets selected by BFA and BIL may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA and BIL in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. Metals and Mining Industry Risk. Companies in the metals and mining industry are susceptible to fluctuations in worldwide metal prices and extraction and production costs. In addition, metals and mining companies may have significant operations in areas at risk for social and political unrest, security concerns and environmental damage. These companies may also be at risk for increased government regulation and intervention. Such risks may adversely affect the issuers to which the Fund has exposure. Money Market Instruments Risk. The value of money market instruments may be affected by changing interest rates and by changes in the credit ratings of the investments. If a significant amount of the Fund's assets are invested in money market instruments, it will be more difficult for the Fund to achieve its investment objective. An investment in a money market fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (“FDIC”) or any other government agency. It is possible to lose money by investing in a money market fund. Money market funds other than government money market funds or retail money market funds “float” their NAV instead of using a stable $1.00 per share price. National Closed Market Trading Risk. To the extent that the underlying securities held by the Fund trade on foreign exchanges or in foreign markets that may be closed when the securities exchange on which the Fund’s shares trade is open, there are likely to be deviations between the current price of such an underlying security and the last quoted price for the underlying security (i.e., the Fund’s quote from the closed foreign market). These deviations could result in premiums or discounts to the Fund’s NAV that may be greater than those experienced by other ETFs. Non-U.S. Securities Risk. Investments in the securities of non-U.S. issuers are subject to the risks associated with investing in those non-U.S. markets, such as heightened risks of inflation or nationalization. The Fund may lose money due to political, economic and geographic events affecting issuers of non-U.S. securities or non-U.S. markets. In addition, non-U.S. securities markets may trade a small number of securities and may be unable to respond effectively to changes in trading volume, potentially making prompt liquidation of holdings difficult or impossible at times. Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks. Reliance on Trading Partners Risk. The Fund invests in countries or regions whose economies are heavily dependent upon trading with key partners. Any reduction in this trading may have an adverse impact on the Fund's investments. Through its holdings of securities of certain issuers, the Fund is specifically exposed to North American Economic Risk. Risk of Investing in Agriculture and Livestock. Investments in the agricultural and livestock sectors may be volatile and change unpredictably as a result of many factors, such as legislative or regulatory developments relating to food safety, the imposition of tariffs or other trade restraints, and the supply and demand of each commodity. Increased competition and changes in consumer tastes and spending can also influence the demand for agricultural and livestock products, affecting the price of such commodities and the performance of the Fund. Risk of Investing in Developed Countries. The Fund’s investment in developed country issuers may subject the Fund to regulatory, political, currency, security, economic and other risks associated with developed countries. Developed countries tend to represent a significant portion of the global economy and have generally experienced slower economic growth than some less developed countries. Certain developed countries have experienced security concerns, such as terrorism and strained international relations. Incidents involving a country’s or region’s security may cause uncertainty in its markets and may adversely affect its economy and the Fund’s investments. In addition, developed countries may be adversely impacted by changes to the economic conditions of certain key trading partners, regulatory burdens, debt burdens and the price or availability of certain commodities. Risk of Investing in the U.S. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure. Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses. Certain standardized interest rate and credit default swaps are required to be traded on an exchange or trading platform and centrally cleared. Most other swaps are entered into a negotiated, bi-lateral basis and traded in the over-the-counter market. Swaps are subject to bi-lateral variation margin. Initial margin requirements are in the process of being phased in and should be effective by 2020. Securities Lending Risk. The Fund may engage in securities lending. Securities lending involves the risk that the Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund. Subsidiary Risk. In compliance with Subchapter M of the Internal Revenue Code, the Fund may invest up to 25% of its total assets in the Subsidiary. By investing in the Subsidiary, the Fund is indirectly exposed to the risks associated with the Subsidiary’s investments. The Subsidiary is not registered under the 1940 Act, and, unless otherwise noted in this Prospectus, is not subject to the investor protections of the 1940 Act. Changes in the laws of the U.S. and/or the Cayman Islands could result in the inability of the Fund and/or the Subsidiary to operate as described in the Prospectus and the Statement of Additional Information (“SAI”), and could adversely affect the Fund. Tax Risk. The Fund invests in commodity-linked derivatives indirectly through the Subsidiary because income from these investments, if made directly, might not be treated as “qualifying income” for purposes of the Fund qualifying as a regulated investment company (“RIC”) for U.S. federal income tax purposes. The Fund expects its income with respect to the Subsidiary to be qualifying income. There is a risk that the U.S. Internal Revenue Service (“IRS”) could issue regulations or other guidance holding, or could assert, that the Fund’s income with respect to the Subsidiary will not be considered “qualifying income” for purposes of the Fund remaining qualified as a RIC for U.S. federal income tax purposes. In such circumstances, the Fund may be required to make changes to its operations, which may reduce the Fund’s ability to gain investment exposure to commodities. Fund shareholders may also experience adverse tax consequences in such circumstances. Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund's valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>Performance Information </b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-800-iShares (1-800-474-2737) (toll free)
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.iShares.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>Year by Year Returns (Years Ended December 31)</b>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The best calendar quarter return during the periods shown above was 13.13% in the 2nd quarter of 2016; the worst was -18.08% in the 3rd quarter of 2015. Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).
Performance Table Heading	rr_PerformanceTableHeading	<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”).
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.
iShares Commodities Select Strategy ETF | iShares Commodities Select Strategy ETF
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.48%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	none	[1]
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	none	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.48%
Fee Waiver	rr_FeeWaiverOrReimbursementOverAssets	none
Total Annual Fund Operating Expenses After Fee Waiver	rr_NetExpensesOverAssets	0.48%
1 Year	rr_ExpenseExampleYear01	$ 49
3 Years	rr_ExpenseExampleYear03	154
5 Years	rr_ExpenseExampleYear05	269
10 Years	rr_ExpenseExampleYear10	$ 604
2015	rr_AnnualReturn2015	(30.37%)
2016	rr_AnnualReturn2016	21.22%
2017	rr_AnnualReturn2017	11.71%
2018	rr_AnnualReturn2018	(6.60%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	best
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2016
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	13.13%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	worst
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(18.08%)
One Year	rr_AverageAnnualReturnYear01	(6.60%)
Since Fund Inception	rr_AverageAnnualReturnSinceInception	(7.17%)
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 15, 2014
iShares Commodities Select Strategy ETF | Return After Taxes on Distributions | iShares Commodities Select Strategy ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(10.34%)	[2]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	(8.67%)	[2]
iShares Commodities Select Strategy ETF | Return After Taxes on Distributions and Sale of Fund Shares | iShares Commodities Select Strategy ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(3.68%)	[2]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	(5.81%)	[2]
iShares Commodities Select Strategy ETF | S&P GSCI™ Commodity Total Return Index (Index returns do not reflect deductions for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(13.82%)	[3],[4]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	(13.99%)	[3],[4]
iShares Commodities Select Strategy ETF | S&P GSCI™ Dynamic Roll Reduced Energy 70/30 Futures/Equity Blend (Index returns do not reflect deductions for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(4.91%)	[4]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	(11.96%)	[4]

[1] For the most recently completed fiscal year, the amount rounded to 0.00%.

[2] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[3] The S&P GSCI™ Commodity Total Return Index, the Fund's performance benchmark, is an unmanaged index that measures the performance of general commodity price movements and inflation in the world economy.

[4] The S&P GSCI™ Dynamic Roll Reduced Energy 70/30 Futures/Equity Blend is an unmanaged index that is designed to measure the performance of a multi-asset allocation strategy that consists of a futures-based commodities index and an equity-based index that is based on various commodity-related GICS subsectors.

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iShares Gold Strategy ETF

iSHARES^® GOLD STRATEGY ETF<br />Ticker: IAUF                                 Stock Exchange: Cboe BZX

<b>Investment Objective </b>

The iShares Gold Strategy ETF (the “Fund”) seeks to provide exposure, on a total return basis, to the price performance of gold.

<b>Fees and Expenses </b>

The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities, commodities or other financial instruments and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and any extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment products. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. BFA, the investment adviser to the Fund, has contractually agreed to 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 investments in other exchange-traded products (“ETPs”) sponsored by BFA or its affiliates and other funds advised by BFA or its affiliates through February 29, 2024, provided that the waiver be no greater than the Fund's management fee of 0.25%. The contractual waiver may be terminated prior to February 29, 2024 only upon written agreement of the Trust and BFA.

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

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

Annual Fund Operating Expenses	Management Fees	Distribution and Service (12b-1) Fees	Other Expenses	Acquired Fund Fees and Expenses		Total Annual Fund Operating Expenses	Fee Waiver		Total Annual Fund Operating Expenses After Fee Waiver
iShares Gold Strategy ETF | iShares Gold Strategy ETF	0.25%	none	none	0.07%	[1]	0.32%	(0.07%)	[1]	0.25%

<b>Example. </b>

This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example	1 Year	3 Years
iShares Gold Strategy ETF | iShares Gold Strategy ETF | USD ($)	26	80

<b>Portfolio Turnover.</b>

The Fund may pay transaction costs, such as commissions, when it buys and sells securities or other assets (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. From inception (June 6, 2018) to the most recent fiscal year end, the Fund's portfolio turnover rate was 13% of the average value of its portfolio.

<b>Principal Investment Strategies</b>

The Fund seeks to achieve its investment objective by investing primarily in a combination of (i) exchange-traded gold futures contracts and other exchange-traded or over-the-counter (“OTC”) derivatives (i.e., forward contracts, futures, options and swaps) that correlate to the investment returns of physical gold, based on the notional value of such derivative instruments; and (ii) ETPs backed by or linked to physical gold, which may include the iShares Gold Trust (the “Gold Trust”) ((i) and (ii) together, the “Gold Investments”). The Fund may invest up to 20% of the Fund’s assets in OTC derivatives. In seeking total return, the Fund additionally aims to generate interest income and capital appreciation through a cash management strategy consisting primarily of cash and cash equivalents and short-term government obligations (collectively, “Fixed-Income Investments”). The Fund is an actively managed exchange-traded fund (“ETF”) and does not seek to replicate the performance of a specified index.

While the Fund is not an index fund, the Fund’s investment strategy related to the Gold Investments generally seeks to maximize correlation with the Bloomberg Composite Gold Index (the “Bloomberg Benchmark”), which is comprised of exchange-traded gold futures contracts and one or more ETPs backed by or linked to physical gold. The Bloomberg Benchmark is designed to track the price performance of gold. Although the Fund generally holds, among other instruments, the same futures contracts under the same futures rolling schedule, and the same ETPs backed by or linked to physical gold, as those included in the Bloomberg Benchmark, the Fund is not obligated to invest in any such futures contracts or ETPs included in, and does not seek to track the performance of, the Bloomberg Benchmark.

The ETPs held by the Fund may invest in physical gold bullion or OTC or exchange-traded derivatives on gold bullion, such as forward contracts, futures, options and swaps. The ETPs held by the Fund may be sponsored by an affiliate of BFA or by an unaffiliated entity, and may be structured as, among others, exchange-traded commodities that track the price of gold or exchange-traded notes with interest and/or principal payments linked to the price of gold.

The Fund seeks to gain exposure to the Gold Investments by investing through a wholly-owned subsidiary organized in the Cayman Islands (the “Subsidiary”). The Subsidiary is advised by BFA and has the same investment objective as the Fund. Unlike the Fund, the Subsidiary is not an investment company registered under the Investment Company Act of 1940, as amended (the “1940 Act”). The Subsidiary invests solely in the Gold Investments and cash and cash equivalents.

In compliance with Subchapter M of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”), the Fund may invest up to 25% of its total assets in the Subsidiary. The Fund’s Gold Investments held in the Subsidiary are intended to provide the Fund with exposure to the gold market consistent with current U.S. federal income tax laws applicable to investment companies such as the Fund, which limit the ability of investment companies to invest directly in the Gold Investments.

The remainder of the Fund’s assets will be invested directly by the Fund, primarily in Fixed-Income Investments, including repurchase agreements, money market instruments, U.S. government and agency securities, treasury inflation-protected securities and sovereign debt obligations of non-U.S. countries. The Fund invests in Fixed-Income Investments for investment purposes and to collateralize the Subsidiary’s investments in derivatives.

The Commodity Futures Trading Commission (“CFTC”) has adopted certain requirements that subject registered investment companies and their advisers to regulation by the CFTC if a registered investment company invests more than a prescribed level of its net asset value in CFTC-regulated futures, options and swaps, or if a registered investment company markets itself as providing investment exposure to such instruments. Due to the Fund's potential use of CFTC-regulated futures, options and swaps above the prescribed levels, it is considered a “commodity pool” under the Commodity Exchange Act (“CEA”).

<b>Summary of Principal Risks</b>

As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is actively managed and is not an index-based ETF.

Asset Class Risk. Securities and other assets in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes (including the futures market).

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

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of the Prospectus), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting.

Cash Management Risk. If a significant amount of the Fund’s assets are invested in cash and cash equivalents, the Fund may underperform other funds that do not similarly invest in cash and cash equivalents for investment purposes and/or to collateralize derivative instruments.

Commodity-Linked Derivatives Risk. The value of a commodity-linked derivative instrument typically is based upon the price movements of the underlying commodity or an economic variable linked to such price movements. The prices of commodity-related investments may fluctuate quickly and dramatically as a result of changes affecting a particular commodity and may not correlate to price movements in other asset classes, such as stocks, bonds and cash. Commodity-linked derivatives are subject to the risk that the counterparty to the transaction, the exchange or trading facility on which they trade or the applicable clearing house may default or otherwise fail to perform. In addition, each exchange or trading facility on which the derivatives are traded has the right to suspend or limit trading in all futures or other instruments that it lists. The Fund’s use of commodity-linked derivatives may also have a leveraging effect on the Fund’s portfolio. Leverage generally magnifies the effect of a change in the value of an asset and creates a risk of loss of value on a larger pool of assets than the Fund would otherwise have had. The Fund is required to post margin in respect to its holdings in derivatives. Each of these factors and events could have a significant negative impact on the Fund. The Fund is specifically exposed to the Risk of Investing in Gold.

Commodity Regulatory Risk. The Fund and the Subsidiary are deemed commodity pools and BFA is considered a “commodity pool operator” with respect to the Fund under the CEA. BFA is therefore subject to regulation by the SEC and the CFTC. BFA is also subject to regulation by National Futures Association (“NFA”). The regulatory requirements governing the use of commodity futures, options, certain swaps or certain other investments could change at any time.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class.

Counterparty Risk. Certain commodity-linked derivative instruments, swap agreements and other forms of financial instruments that involve counterparties subject the Fund to the risk that the counterparty could default on its obligations under the agreement, either through the counterparty’s bankruptcy or failure to perform its obligations. In the event of a counterparty default, the Fund could experience lengthy delays in recovering some or all of its assets or obtain no recovery at all. The Fund’s investments in the futures markets also introduce the risk that its futures commission merchant (“FCM”) could default on an obligation set forth in an agreement between the Fund and the FCM, including the FCM’s obligation to return margin posted in connection with the Fund’s futures contracts.

Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation.

Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers (including the benchmark provider), market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests.

Derivatives Risk. The Fund’s use of derivatives may reduce the Fund’s returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Counterparty risk for OTC derivatives is generally higher than that for derivatives traded on an exchange or through a clearing house. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives.

Futures Contract Risk. Futures are standardized, exchange-traded contracts that obligate a purchaser to take delivery, and a seller to make delivery, of a specific amount of an asset at a specified future date at a specified price. Unlike equities, which typically entitle the holder to a continuing ownership stake in a corporation, futures contracts normally specify a certain date for settlement in cash based on the level of the reference rate. The primary risks associated with the use of futures contracts are: (i) the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; (ii) possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; (iii) losses caused by unanticipated market movements, which are potentially unlimited; (iv) BFA’s inability to predict correctly the direction of prices and other economic factors; and (v) the possibility that the counterparty will default in the performance of its obligations. To the extent that the Fund invests in rolling futures contracts, it may be subject to additional risk.

Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, or the Fund otherwise needs to purchase additional bonds.

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

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

Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities or assets selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective.

Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns.

Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

Money Market Instruments Risk. The value of money market instruments may be affected by changing interest rates and by changes in the credit ratings of the investments. If a significant amount of the Fund's assets are invested in money market instruments, it will be more difficult for the Fund to achieve its investment objective. An investment in a money market fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (“FDIC”) or any other government agency. It is possible to lose money by investing in a money market fund. Money market funds other than government money market funds or retail money market funds “float” their NAV instead of using a stable $1.00 per share price.

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

Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Risk of Investing in ETPs. Through the Fund’s investments in ETPs, which may be affiliated or unaffiliated with the Fund, the Fund is subject to the risks associated with the ETPs’ investments. The Fund’s exposure to particular risks of an ETP generally will be proportionate to the Fund’s allocation to the ETP. To the extent the Fund invests a portion of its assets in the Gold Trust, which seeks to reflect generally the performance of the price of gold, the Fund is subject to the risks associated with the Gold Trust, including the possibility that the market price of its shares could decrease, and the value of the Fund’s investment in the Gold Trust may fluctuate, sometimes rapidly or unpredictably. The Gold Trust is sponsored by an affiliate of BFA that receives a fee in exchange for assuming certain administrative and marketing expenses of the Gold Trust, which may create a conflict of interest for BFA in determining whether, and under what circumstances, to purchase or sell shares in the Gold Trust.

Risk of Investing in Gold. The Fund has a substantial exposure to gold through its investments in the Gold Investments. Thus, the Fund’s portfolio may be adversely affected by changes or trends in the price of gold. The price of gold and of gold-related instruments historically has been volatile, which may adversely affect the value of Gold Investments. Governments, central banks, or other larger holders can influence the production and sale of gold, which may adversely affect the performance of the Fund.

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

Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses.

Small Fund Risk. When the Fund’s size is small, the Fund may experience low trading volume and wide bid/ask spreads. In addition, the Fund may face the risk of being delisted if the Fund does not meet certain conditions of the listing exchange.

Subsidiary Risk. In compliance with Subchapter M of the Internal Revenue Code, the Fund may invest up to 25% of its total assets in the Subsidiary. By investing in the Subsidiary, the Fund is indirectly exposed to the risks associated with the Subsidiary’s investments. The Subsidiary is not registered under the 1940 Act, and, unless otherwise noted in this Prospectus, is not subject to the investor protections of the 1940 Act. Changes in the laws of the U.S. and/or the Cayman Islands could result in the inability of the Fund and/or the Subsidiary to operate as described in the Prospectus and the Statement of Additional Information (“SAI”), and could adversely affect the Fund.

Tax Risk. The Fund invests in commodity-linked derivatives indirectly through the Subsidiary because income from these investments, if made directly, might not be treated as “qualifying income” for purposes of the Fund qualifying as a regulated investment company (“RIC”) for U.S. federal income tax purposes. The Fund expects its income with respect to the Subsidiary to be qualifying income. There is a risk that the U.S. Internal Revenue Service (“IRS”) could issue regulations or other guidance holding, or could assert, that the Fund’s income with respect to the Subsidiary will not be considered “qualifying income” for purposes of the Fund remaining qualified as a RIC for U.S. federal income tax purposes. In such circumstances, the Fund may be required to make changes to its operations, which may reduce the Fund’s ability to gain investment exposure to commodities. Fund shareholders may also experience adverse tax consequences in such circumstances.

Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund's valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities or other instruments may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or other instruments or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.

<b>Performance Information</b>

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

[1] The expense information in the table has been restated to reflect current fees.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	iShares U.S. ETF Trust
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
iShares Gold Strategy ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	iSHARES<sup>®</sup> GOLD STRATEGY ETF<br />Ticker: IAUF                                 Stock Exchange: Cboe BZX
Objective [Heading]	rr_ObjectiveHeading	<b>Investment Objective </b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The iShares Gold Strategy ETF (the “Fund”) seeks to provide exposure, on a total return basis, to the price performance of gold.
Expense [Heading]	rr_ExpenseHeading	<b>Fees and Expenses </b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities, commodities or other financial instruments and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and any extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment products. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. BFA, the investment adviser to the Fund, has contractually agreed to 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 investments in other exchange-traded products (“ETPs”) sponsored by BFA or its affiliates and other funds advised by BFA or its affiliates through February 29, 2024, provided that the waiver be no greater than the Fund's management fee of 0.25%. The contractual waiver may be terminated prior to February 29, 2024 only upon written agreement of the Trust and BFA. You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>Annual Fund Operating Expenses<br/>(ongoing expenses that you pay each year as a<br/>percentage of the value of your investments)</b>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	February 29, 2024
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>Portfolio Turnover.</b>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund may pay transaction costs, such as commissions, when it buys and sells securities or other assets (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. From inception (June 6, 2018) to the most recent fiscal year end, the Fund's portfolio turnover rate was 13% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	13.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Expenses Restated to Reflect Current [Text]	rr_ExpensesRestatedToReflectCurrent	The expense information in the table has been restated to reflect current fees.
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>Example. </b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>Principal Investment Strategies</b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its investment objective by investing primarily in a combination of (i) exchange-traded gold futures contracts and other exchange-traded or over-the-counter (“OTC”) derivatives (i.e., forward contracts, futures, options and swaps) that correlate to the investment returns of physical gold, based on the notional value of such derivative instruments; and (ii) ETPs backed by or linked to physical gold, which may include the iShares Gold Trust (the “Gold Trust”) ((i) and (ii) together, the “Gold Investments”). The Fund may invest up to 20% of the Fund’s assets in OTC derivatives. In seeking total return, the Fund additionally aims to generate interest income and capital appreciation through a cash management strategy consisting primarily of cash and cash equivalents and short-term government obligations (collectively, “Fixed-Income Investments”). The Fund is an actively managed exchange-traded fund (“ETF”) and does not seek to replicate the performance of a specified index. While the Fund is not an index fund, the Fund’s investment strategy related to the Gold Investments generally seeks to maximize correlation with the Bloomberg Composite Gold Index (the “Bloomberg Benchmark”), which is comprised of exchange-traded gold futures contracts and one or more ETPs backed by or linked to physical gold. The Bloomberg Benchmark is designed to track the price performance of gold. Although the Fund generally holds, among other instruments, the same futures contracts under the same futures rolling schedule, and the same ETPs backed by or linked to physical gold, as those included in the Bloomberg Benchmark, the Fund is not obligated to invest in any such futures contracts or ETPs included in, and does not seek to track the performance of, the Bloomberg Benchmark. The ETPs held by the Fund may invest in physical gold bullion or OTC or exchange-traded derivatives on gold bullion, such as forward contracts, futures, options and swaps. The ETPs held by the Fund may be sponsored by an affiliate of BFA or by an unaffiliated entity, and may be structured as, among others, exchange-traded commodities that track the price of gold or exchange-traded notes with interest and/or principal payments linked to the price of gold. The Fund seeks to gain exposure to the Gold Investments by investing through a wholly-owned subsidiary organized in the Cayman Islands (the “Subsidiary”). The Subsidiary is advised by BFA and has the same investment objective as the Fund. Unlike the Fund, the Subsidiary is not an investment company registered under the Investment Company Act of 1940, as amended (the “1940 Act”). The Subsidiary invests solely in the Gold Investments and cash and cash equivalents. In compliance with Subchapter M of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”), the Fund may invest up to 25% of its total assets in the Subsidiary. The Fund’s Gold Investments held in the Subsidiary are intended to provide the Fund with exposure to the gold market consistent with current U.S. federal income tax laws applicable to investment companies such as the Fund, which limit the ability of investment companies to invest directly in the Gold Investments. The remainder of the Fund’s assets will be invested directly by the Fund, primarily in Fixed-Income Investments, including repurchase agreements, money market instruments, U.S. government and agency securities, treasury inflation-protected securities and sovereign debt obligations of non-U.S. countries. The Fund invests in Fixed-Income Investments for investment purposes and to collateralize the Subsidiary’s investments in derivatives. The Commodity Futures Trading Commission (“CFTC”) has adopted certain requirements that subject registered investment companies and their advisers to regulation by the CFTC if a registered investment company invests more than a prescribed level of its net asset value in CFTC-regulated futures, options and swaps, or if a registered investment company markets itself as providing investment exposure to such instruments. Due to the Fund's potential use of CFTC-regulated futures, options and swaps above the prescribed levels, it is considered a “commodity pool” under the Commodity Exchange Act (“CEA”).
Risk [Heading]	rr_RiskHeading	<b>Summary of Principal Risks</b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is actively managed and is not an index-based ETF. Asset Class Risk. Securities and other assets in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes (including the futures market). Assets Under Management (AUM) Risk. From time to time, an Authorized Participant (as defined in the Creations and Redemptions section of this prospectus (the “Prospectus”)), a third-party investor, the Fund’s adviser or an affiliate of the Fund’s adviser, or a fund may invest in the Fund and hold its investment for a specific period of time to allow the Fund to achieve size or scale. There can be no assurance that any such entity would not redeem its investment or that the size of the Fund would be maintained at such levels, which could negatively impact the Fund. Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of the Prospectus), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Cash Management Risk. If a significant amount of the Fund’s assets are invested in cash and cash equivalents, the Fund may underperform other funds that do not similarly invest in cash and cash equivalents for investment purposes and/or to collateralize derivative instruments. Commodity-Linked Derivatives Risk. The value of a commodity-linked derivative instrument typically is based upon the price movements of the underlying commodity or an economic variable linked to such price movements. The prices of commodity-related investments may fluctuate quickly and dramatically as a result of changes affecting a particular commodity and may not correlate to price movements in other asset classes, such as stocks, bonds and cash. Commodity-linked derivatives are subject to the risk that the counterparty to the transaction, the exchange or trading facility on which they trade or the applicable clearing house may default or otherwise fail to perform. In addition, each exchange or trading facility on which the derivatives are traded has the right to suspend or limit trading in all futures or other instruments that it lists. The Fund’s use of commodity-linked derivatives may also have a leveraging effect on the Fund’s portfolio. Leverage generally magnifies the effect of a change in the value of an asset and creates a risk of loss of value on a larger pool of assets than the Fund would otherwise have had. The Fund is required to post margin in respect to its holdings in derivatives. Each of these factors and events could have a significant negative impact on the Fund. The Fund is specifically exposed to the Risk of Investing in Gold. Commodity Regulatory Risk. The Fund and the Subsidiary are deemed commodity pools and BFA is considered a “commodity pool operator” with respect to the Fund under the CEA. BFA is therefore subject to regulation by the SEC and the CFTC. BFA is also subject to regulation by National Futures Association (“NFA”). The regulatory requirements governing the use of commodity futures, options, certain swaps or certain other investments could change at any time. Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. Counterparty Risk. Certain commodity-linked derivative instruments, swap agreements and other forms of financial instruments that involve counterparties subject the Fund to the risk that the counterparty could default on its obligations under the agreement, either through the counterparty’s bankruptcy or failure to perform its obligations. In the event of a counterparty default, the Fund could experience lengthy delays in recovering some or all of its assets or obtain no recovery at all. The Fund’s investments in the futures markets also introduce the risk that its futures commission merchant (“FCM”) could default on an obligation set forth in an agreement between the Fund and the FCM, including the FCM’s obligation to return margin posted in connection with the Fund’s futures contracts. Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation. Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers (including the benchmark provider), market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests. Derivatives Risk. The Fund’s use of derivatives may reduce the Fund’s returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Counterparty risk for OTC derivatives is generally higher than that for derivatives traded on an exchange or through a clearing house. A risk of the Fund’s use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund to sell or otherwise close a derivatives position could expose the Fund to losses and could make derivatives more difficult for the Fund to value accurately. The Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives. Futures Contract Risk. Futures are standardized, exchange-traded contracts that obligate a purchaser to take delivery, and a seller to make delivery, of a specific amount of an asset at a specified future date at a specified price. Unlike equities, which typically entitle the holder to a continuing ownership stake in a corporation, futures contracts normally specify a certain date for settlement in cash based on the level of the reference rate. The primary risks associated with the use of futures contracts are: (i) the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; (ii) possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; (iii) losses caused by unanticipated market movements, which are potentially unlimited; (iv) BFA’s inability to predict correctly the direction of prices and other economic factors; and (v) the possibility that the counterparty will default in the performance of its obligations. To the extent that the Fund invests in rolling futures contracts, it may be subject to additional risk. Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, or the Fund otherwise needs to purchase additional bonds. Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. Issuer Risk. The performance of the Fund depends on the performance of individual securities or other assets to which the Fund has exposure. Changes in the financial condition or credit rating of an issuer of those securities or assets may cause the value of the securities or assets to decline. Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities or assets selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. Money Market Instruments Risk. The value of money market instruments may be affected by changing interest rates and by changes in the credit ratings of the investments. If a significant amount of the Fund's assets are invested in money market instruments, it will be more difficult for the Fund to achieve its investment objective. An investment in a money market fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (“FDIC”) or any other government agency. It is possible to lose money by investing in a money market fund. Money market funds other than government money market funds or retail money market funds “float” their NAV instead of using a stable $1.00 per share price. Non-Diversification Risk. The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers. As a result, the Fund's performance may depend on the performance of a small number of issuers. Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks. Risk of Investing in ETPs. Through the Fund’s investments in ETPs, which may be affiliated or unaffiliated with the Fund, the Fund is subject to the risks associated with the ETPs’ investments. The Fund’s exposure to particular risks of an ETP generally will be proportionate to the Fund’s allocation to the ETP. To the extent the Fund invests a portion of its assets in the Gold Trust, which seeks to reflect generally the performance of the price of gold, the Fund is subject to the risks associated with the Gold Trust, including the possibility that the market price of its shares could decrease, and the value of the Fund’s investment in the Gold Trust may fluctuate, sometimes rapidly or unpredictably. The Gold Trust is sponsored by an affiliate of BFA that receives a fee in exchange for assuming certain administrative and marketing expenses of the Gold Trust, which may create a conflict of interest for BFA in determining whether, and under what circumstances, to purchase or sell shares in the Gold Trust. Risk of Investing in Gold. The Fund has a substantial exposure to gold through its investments in the Gold Investments. Thus, the Fund’s portfolio may be adversely affected by changes or trends in the price of gold. The price of gold and of gold-related instruments historically has been volatile, which may adversely affect the value of Gold Investments. Governments, central banks, or other larger holders can influence the production and sale of gold, which may adversely affect the performance of the Fund. Risk of Investing in the U.S. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure. Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses. Small Fund Risk. When the Fund’s size is small, the Fund may experience low trading volume and wide bid/ask spreads. In addition, the Fund may face the risk of being delisted if the Fund does not meet certain conditions of the listing exchange. Subsidiary Risk. In compliance with Subchapter M of the Internal Revenue Code, the Fund may invest up to 25% of its total assets in the Subsidiary. By investing in the Subsidiary, the Fund is indirectly exposed to the risks associated with the Subsidiary’s investments. The Subsidiary is not registered under the 1940 Act, and, unless otherwise noted in this Prospectus, is not subject to the investor protections of the 1940 Act. Changes in the laws of the U.S. and/or the Cayman Islands could result in the inability of the Fund and/or the Subsidiary to operate as described in the Prospectus and the Statement of Additional Information (“SAI”), and could adversely affect the Fund. Tax Risk. The Fund invests in commodity-linked derivatives indirectly through the Subsidiary because income from these investments, if made directly, might not be treated as “qualifying income” for purposes of the Fund qualifying as a regulated investment company (“RIC”) for U.S. federal income tax purposes. The Fund expects its income with respect to the Subsidiary to be qualifying income. There is a risk that the U.S. Internal Revenue Service (“IRS”) could issue regulations or other guidance holding, or could assert, that the Fund’s income with respect to the Subsidiary will not be considered “qualifying income” for purposes of the Fund remaining qualified as a RIC for U.S. federal income tax purposes. In such circumstances, the Fund may be required to make changes to its operations, which may reduce the Fund’s ability to gain investment exposure to commodities. Fund shareholders may also experience adverse tax consequences in such circumstances. Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund's valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities or other instruments may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or other instruments or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	<b>Non-Diversification Risk.</b> The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers. As a result, the Fund's performance may depend on the performance of a small number of issuers.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>Performance Information</b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	As of the date of the Prospectus, the Fund has been in operation for less than one full calendar year and therefore does not report its performance information.
Performance One Year or Less [Text]	rr_PerformanceOneYearOrLess	As of the date of the Prospectus, the Fund has been in operation for less than one full calendar year and therefore does not report its performance information.
iShares Gold Strategy ETF | iShares Gold Strategy ETF
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.25%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	none
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.07%	[1]
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.32%
Fee Waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.07%)	[1]
Total Annual Fund Operating Expenses After Fee Waiver	rr_NetExpensesOverAssets	0.25%
1 Year	rr_ExpenseExampleYear01	$ 26
3 Years	rr_ExpenseExampleYear03	$ 80

[1] The expense information in the table has been restated to reflect current fees.

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iShares Inflation Hedged Corporate Bond ETF

iSHARES^® INFLATION HEDGED CORPORATE BOND ETF <br/> Ticker: LQDI                                 Stock Exchange: Cboe BZX

<b>Investment Objective </b>

The iShares Inflation Hedged Corporate Bond ETF (the “Fund”) seeks to mitigate the inflation risk of a portfolio composed of U.S. dollar-denominated, investment-grade corporate bonds.

<b>Fees and Expenses</b>

The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees so that the Fund’s total annual fund operating expenses after fee waiver is equal to the Acquired Fund Fees and Expenses attributable to the Fund’s investment in the iShares iBoxx $ Investment Grade Corporate Bond ETF (“LQD” or the “Underlying Fund”), after taking into account any fee waivers by LQD, plus 0.05% through February 28, 2023. The contractual waiver may be terminated prior to February 28, 2023 only upon written agreement of the Trust and BFA.

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

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

Annual Fund Operating Expenses	Management Fees	Distribution and Service (12b-1) Fees	Other Expenses	Acquired Fund Fees and Expenses	Total Annual Fund Operating Expenses	Fee Waiver	Total Annual Fund Operating Expenses After Fee Waiver
iShares Inflation Hedged Corporate Bond ETF | iShares Inflation Hedged Corporate Bond ETF	0.20%	none	none	0.14%	0.34%	(0.15%)	0.19%

<b>Example. </b>

This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example	1 Year	3 Years
iShares Inflation Hedged Corporate Bond ETF | iShares Inflation Hedged Corporate Bond ETF | USD ($)	19	61

<b>Portfolio Turnover.</b>

The Fund and the Underlying Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate for the Fund or the Underlying Fund may indicate higher transaction costs and may cause the Fund or the Underlying Fund to incur increased expenses. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example (except costs to the Underlying Fund included as part of Acquired Fund Fees and Expenses), affect the Fund’s performance. From inception (May 8, 2018) to the most recent fiscal year end, the Fund's portfolio turnover rate was 0% of the average value of its portfolio. To the extent the Underlying Fund incurs costs from high portfolio turnover, such costs may have a negative effect on the performance of the Fund.

<b>Principal Investment Strategies</b>

The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in the Underlying Fund, U.S. dollar-denominated investment-grade corporate bonds, in one or more other underlying funds that principally invest in investment-grade corporate bonds, and in inflation swaps. The Fund intends to invest a substantial portion of its assets in the Underlying Fund. The Fund attempts to mitigate the inflation risk of the underlying securities or the Underlying Fund (as determined by BFA) primarily through the use of inflation swaps (i.e., contracts in which the Fund will make fixed-rate payments based on notional amount while receiving floating-rate payments determined from an inflation index), which are managed on an active basis. The Fund may also invest in other instruments designed to transfer inflation risk from one party to another, including but not limited to Treasury Inflation Protected Securities (“TIPS”), total return swaps, credit default swaps, interest rate swaps and U.S. Treasury futures (collectively with inflation swaps, “inflation hedging instruments”). The Fund’s investments in inflation hedging instruments are not intended to mitigate credit risk or other factors influencing the price of investment-grade corporate bonds, which may have a greater impact on the bonds' returns than inflation rates. Moreover, to the extent that inflation risk has been priced into the investment-grade corporate bonds owned by the Fund or the Underlying Fund, the Fund will underperform the Underlying Fund even during inflationary periods.

The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index.

The Fund may also invest in other ETFs (including the Underlying Fund and other iShares funds), U.S. government securities, futures, options and swap contracts, short-term paper, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates.

The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index.

The Fund may lend securities from its portfolio representing up to one-third of the value of the Fund's total assets (including the value of the collateral received).

<b>Summary of Principal Risks</b>

As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below (either directly or through its investments in the Underlying Fund), any of which may adversely affect the Fund's NAV, trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF.

Asset Class Risk. Securities and other assets in the Fund's or the Underlying Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes.

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

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of the Prospectus), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting.

Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund or the Underlying Fund may “call” or repay the security before its stated maturity, and the Fund or the Underlying Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's or Underlying Fund's income, or in securities with greater risks or with other less favorable features.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's or the Underlying Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class.

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

Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s or Underlying Fund's investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation.

Cyber Security Risk. Failures or breaches of the electronic systems of the Fund or the Underlying Fund, the Fund's or the Underlying Fund's adviser, distributor, or other service providers (including the benchmark provider), market makers, Authorized Participants, hedging counterparties to the Fund or the issuers of securities in which the Fund or the Underlying Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants, hedging counterparties to the Fund or issuers of securities in which the Fund or the Underlying Fund invests.

Derivatives Risk. The Fund’s or Underlying Fund's use of derivatives may reduce the Fund’s or Underlying Fund's returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Counterparty risk for over-the-counter (“OTC”) derivatives is generally higher than that for derivatives traded on an exchange or through a clearing house. A risk of the Fund’s or Underlying Fund's use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund or Underlying Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund or Underlying Fund to sell or otherwise close a derivatives position could expose the Fund or Underlying Fund to losses and could make derivatives more difficult for the Fund or Underlying Fund to value accurately. The Fund or Underlying Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund or Underlying Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund or Underlying Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund or Underlying Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund or Underlying Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives.

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

Financials Sector Risk. Performance of companies in the financials sector may be adversely impacted by many factors, including, among others, changes in government regulations, economic conditions, and interest rates, credit rating downgrades, and decreased liquidity in credit markets. The extent to which the Fund may invest in a company that engages in securities-related activities or banking is limited by applicable law. The impact of changes in capital requirements and recent or future regulation of any individual financial company, or of the financials sector as a whole, cannot be predicted. In recent years, cyber-attacks and technology malfunctions and failures have become increasingly frequent in this sector and have caused significant losses to companies in this sector, which may negatively impact the Fund.

Geographic Risk. A natural disaster could occur in a geographic region in which the Fund or the Underlying Fund invests, which could affect the economy or particular business operations of companies in the specific geographic region, causing an adverse impact on the Fund's or the Underlying Fund's investments in the affected region.

Hedging Risk. The Fund seeks to mitigate the potential impact of inflation on the performance of investment-grade corporate bonds by investing in inflation hedging instruments. The Fund’s use of inflation hedging instruments is intended solely to mitigate inflation risk and is not intended to mitigate credit risk, interest rate risk, or other factors influencing the price of investment-grade corporate bonds, which may have a greater impact on the bonds’ returns than inflation. There is no guarantee that the Fund’s positions in inflation hedging instruments will completely eliminate the inflation risk of the long positions in investment-grade corporate bonds. In addition, when interest rates rise above the inflation rate, the Fund’s investments will generally underperform a portfolio comprised solely of the investment-grade corporate bonds. In certain low inflation rate environments, the Fund’s hedging strategy could result in disproportionately larger losses in the positions in inflation hedging instruments as compared to gains in the long investment-grade corporate bond positions attributable to interest rate changes. The Fund only seeks to hedge the impact of inflation and, as a result, if floating interest rates rise above the inflation-linked rates, the Fund will not be hedged. There is no guarantee the Fund will have positive returns, even in environments of sharply rising inflation rates in which the Fund’s positions in inflation hedging instruments might be expected to mitigate the effects of such rises. The Fund will incur expenses when entering into positions in inflation hedging instruments. Moreover, to the extent that inflation risk has been priced into the investment-grade corporate bonds owned by the Fund or the Underlying Fund, the Fund will underperform the Underlying Fund even during inflationary periods.

Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices.

Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund or the Underlying Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, bonds in the Underlying Fund's index are substituted, or the Fund or the Underlying Fund otherwise needs to purchase additional bonds.

Industrials Sector Risk. Companies in the industrials sector may be adversely affected by changes in the supply of and demand for products and services, product obsolescence, claims for environmental damage or product liability and changes in general economic conditions, among other factors.

Inflation-Linked Instruments Risk. There can be no assurance that the Consumer Price Index (“CPI”), which typically is referenced by inflation swaps, or any other inflation index will accurately measure the rate of inflation experienced in the U.S. or the rate of expected future inflation reflected in the prices and yields of bonds held by the Fund. CPI swaps may cause the Fund’s NAV and returns to be more volatile and expose the Fund to counterparty risk. The Fund could lose money on both the inflation hedging instruments and the investment-grade corporate bonds, and the present value of the Fund’s portfolio investments could decrease if inflation increases.

Inflation Risk. The Fund seeks to mitigate many of the adverse impacts of inflation on investment-grade corporate bonds held by the Fund and their issuers primarily through the use of swaps linked to the CPI. The CPI is a measure that examines the weighted average of prices of a basket of consumer goods and services, and measures changes in the purchasing power of the U.S. dollar and the rate of inflation. CPI swaps will not mitigate inflation risk regarding distributions made by the Fund itself.

By entering into a CPI swap, the Fund effectively turns the inflation component of the bonds held by the Fund or the Underlying Fund from fixed rates into floating rates. The Fund will lose money on the CPI swap and underperform if inflation is lower than the expected rate being hedged. The Fund will benefit from a CPI swap if actual inflation (as measured by the CPI) during the time period in which the Fund holds the swap is the same or greater than the level of inflation expected for that period. However, if actual inflation (as measured by the CPI) is less than the rate of inflation expected for that period, the Fund generally will lose money on the CPI swap and underperform the Underlying Fund as a result of having entered into the CPI swap.

Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund or the Underlying Fund to decline to the extent that the increase is not linked to inflation or the Fund’s hedging strategy is not effectively implemented. Even if the Fund is hedged against losses due to interest rate increases linked to inflation, interest rate increases may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates, such as increases linked to inflation. In order to hedge the risk of interest rate increases due to inflation, the Fund will take positions in inflation hedging instruments. As a result, when the rate of inflation does not increase or when interest rates increase or decrease inversely to changes in the rate of inflation, the Fund will underperform funds with long-only investments in the same investment-grade corporate bonds as the Fund. There is no guarantee that the Fund or Underlying Fund will have positive performance even in environments of sharply rising inflation. There is no guarantee that the Fund or Underlying Fund will be able to successfully mitigate inflation risk or that bond values and interest rates will match changes in inflation rates.

Interest Rate Swap Risk. Interest rate swaps are subject to risks applicable to swaps generally, including the risk that a counterparty fails to meet its obligations and the risk that the Fund is not able to liquidate such swap in a timely manner or at all, which could result in losses to the Fund. Because the Fund will invest in swaps that are subject to central clearing, these swaps are subject to the risk that a central clearinghouse will go into bankruptcy or become non-operational, and sometimes involve increased transaction costs. Counterparties to OTC swaps are not subject to these risks. An interest rate swap may fail to perform as intended and may not offset adverse changes in interest rates fully or at all. An interest rate swap may also reduce the Fund’s gains due to favorable changes in interest rates and result in losses to the Fund. Counterparties to interest rate swaps are subject to manipulation in the marketplace of the reference benchmark rate, which may affect the utility of the swap as a hedge.

Investment in the Underlying Fund Risk. The Fund expects to invest a substantial portion of its assets in the Underlying Fund, so the Fund’s investment performance is likely to be directly related to the performance of the Underlying Fund, adjusted for the impact of changes in the rate of inflation. The Fund’s NAV will change with changes in the value of the Underlying Fund and other securities and instruments in which the Fund invests based on their market valuations. An investment in the Fund will entail more costs and expenses than a direct investment in the Underlying Fund.

As the Fund’s allocations to the Underlying Fund change from time to time, or to the extent that the expense ratio of the Underlying Fund changes, the weighted average operating expenses borne by the Fund may increase or decrease.

Through its investment in the Underlying Fund, the Fund is exposed to Management Risk, Market Risk, and Market Trading Risk, among other risks.

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

Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective.

Market Risk. The Fund and the Underlying Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns.

Market Trading Risk. The Fund and the Underlying Fund face numerous market trading risks, including the potential lack of an active market for their shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which an arbitrage mechanism will develop. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

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

Operational Risk. The Fund and the Underlying Fund are exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s or the Underlying Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund, the Underlying Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund or the Underlying Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential.

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

Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses.

Securities Lending Risk. The Fund or the Underlying Fund may engage in securities lending. Securities lending involves the risk that the Fund or the Underlying Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund or the Underlying Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund or Underlying Fund.

Small Fund Risk. When the Fund’s size is small, the Fund may experience low trading volume and wide bid/ask spreads. In addition, the Fund may face the risk of being delisted if the Fund does not meet certain conditions of the listing exchange.

Tax Risk. The Fund invests in derivatives. The federal income tax treatment of a derivative may not be as favorable as a direct investment in an underlying asset. Derivatives may produce taxable income and taxable realized gain. Derivatives may adversely affect the timing, character and amount of income the Fund realizes from its investments. As a result, a larger portion of the Fund’s distributions may be treated as ordinary income rather than as capital gains. In addition, certain derivatives are subject to mark-to-market or straddle provisions of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). If such provisions are applicable, there could be an increase (or decrease) in the amount of taxable dividends paid by the Fund. Income from swaps is generally taxable. In addition, the tax treatment of certain derivatives, such as swaps, is unsettled and may be subject to future legislation, regulation or administrative pronouncements issued by the U.S. Internal Revenue Service (“IRS”).

<b>Performance Information</b>

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

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	iShares U.S. ETF Trust
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
iShares Inflation Hedged Corporate Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	iSHARES<sup>®</sup> INFLATION HEDGED CORPORATE BOND ETF <br/> Ticker: LQDI                                 Stock Exchange: Cboe BZX
Objective [Heading]	rr_ObjectiveHeading	<b>Investment Objective </b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The iShares Inflation Hedged Corporate Bond ETF (the “Fund”) seeks to mitigate the inflation risk of a portfolio composed of U.S. dollar-denominated, investment-grade corporate bonds.
Expense [Heading]	rr_ExpenseHeading	<b>Fees and Expenses</b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees so that the Fund’s total annual fund operating expenses after fee waiver is equal to the Acquired Fund Fees and Expenses attributable to the Fund’s investment in the iShares iBoxx $ Investment Grade Corporate Bond ETF (“LQD” or the “Underlying Fund”), after taking into account any fee waivers by LQD, plus 0.05% through February 28, 2023. The contractual waiver may be terminated prior to February 28, 2023 only upon written agreement of the Trust and BFA. You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>Annual Fund Operating Expenses<br/>(ongoing expenses that you pay each year as a<br/>percentage of the value of your investments) </b>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	February 28, 2023
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>Portfolio Turnover.</b>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund and the Underlying Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate for the Fund or the Underlying Fund may indicate higher transaction costs and may cause the Fund or the Underlying Fund to incur increased expenses. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example (except costs to the Underlying Fund included as part of Acquired Fund Fees and Expenses), affect the Fund’s performance. From inception (May 8, 2018) to the most recent fiscal year end, the Fund's portfolio turnover rate was 0% of the average value of its portfolio. To the extent the Underlying Fund incurs costs from high portfolio turnover, such costs may have a negative effect on the performance of the Fund.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	none
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>Example. </b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>Principal Investment Strategies</b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in the Underlying Fund, U.S. dollar-denominated investment-grade corporate bonds, in one or more other underlying funds that principally invest in investment-grade corporate bonds, and in inflation swaps. The Fund intends to invest a substantial portion of its assets in the Underlying Fund. The Fund attempts to mitigate the inflation risk of the underlying securities or the Underlying Fund (as determined by BFA) primarily through the use of inflation swaps (i.e., contracts in which the Fund will make fixed-rate payments based on notional amount while receiving floating-rate payments determined from an inflation index), which are managed on an active basis. The Fund may also invest in other instruments designed to transfer inflation risk from one party to another, including but not limited to Treasury Inflation Protected Securities (“TIPS”), total return swaps, credit default swaps, interest rate swaps and U.S. Treasury futures (collectively with inflation swaps, “inflation hedging instruments”). The Fund’s investments in inflation hedging instruments are not intended to mitigate credit risk or other factors influencing the price of investment-grade corporate bonds, which may have a greater impact on the bonds' returns than inflation rates. Moreover, to the extent that inflation risk has been priced into the investment-grade corporate bonds owned by the Fund or the Underlying Fund, the Fund will underperform the Underlying Fund even during inflationary periods. The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index. The Fund may also invest in other ETFs (including the Underlying Fund and other iShares funds), U.S. government securities, futures, options and swap contracts, short-term paper, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates. The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index. The Fund may lend securities from its portfolio representing up to one-third of the value of the Fund's total assets (including the value of the collateral received).
Risk [Heading]	rr_RiskHeading	<b>Summary of Principal Risks</b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below (either directly or through its investments in the Underlying Fund), any of which may adversely affect the Fund's NAV, trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF. Asset Class Risk. Securities and other assets in the Fund's or the Underlying Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes. Assets Under Management (AUM) Risk. From time to time, an Authorized Participant (as defined in the Creations and Redemptions section of this prospectus (the “Prospectus”)), a third-party investor, the Fund’s adviser or an affiliate of the Fund’s adviser, or a fund may invest in the Fund and hold its investment for a specific period of time to allow the Fund to achieve size or scale. There can be no assurance that any such entity would not redeem its investment or that the size of the Fund would be maintained at such levels, which could negatively impact the Fund. Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of the Prospectus), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund or the Underlying Fund may “call” or repay the security before its stated maturity, and the Fund or the Underlying Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's or Underlying Fund's income, or in securities with greater risks or with other less favorable features. Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's or the Underlying Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. Consumer Staples Sector Risk. The consumer staples sector may be affected by, among other things, marketing campaigns, changes in consumer demands, government regulations and changes in commodity prices. Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s or Underlying Fund's investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation. Cyber Security Risk. Failures or breaches of the electronic systems of the Fund or the Underlying Fund, the Fund's or the Underlying Fund's adviser, distributor, or other service providers (including the benchmark provider), market makers, Authorized Participants, hedging counterparties to the Fund or the issuers of securities in which the Fund or the Underlying Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants, hedging counterparties to the Fund or issuers of securities in which the Fund or the Underlying Fund invests. Derivatives Risk. The Fund’s or Underlying Fund's use of derivatives may reduce the Fund’s or Underlying Fund's returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Counterparty risk for over-the-counter (“OTC”) derivatives is generally higher than that for derivatives traded on an exchange or through a clearing house. A risk of the Fund’s or Underlying Fund's use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund or Underlying Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund or Underlying Fund to sell or otherwise close a derivatives position could expose the Fund or Underlying Fund to losses and could make derivatives more difficult for the Fund or Underlying Fund to value accurately. The Fund or Underlying Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund or Underlying Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund or Underlying Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund or Underlying Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund or Underlying Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives. Extension Risk. During periods of rising interest rates, certain debt obligations may be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in the Fund’s or the Underlying Fund's income and potentially in the value of the Fund’s or an Underlying Fund's investments. Financials Sector Risk. Performance of companies in the financials sector may be adversely impacted by many factors, including, among others, changes in government regulations, economic conditions, and interest rates, credit rating downgrades, and decreased liquidity in credit markets. The extent to which the Fund may invest in a company that engages in securities-related activities or banking is limited by applicable law. The impact of changes in capital requirements and recent or future regulation of any individual financial company, or of the financials sector as a whole, cannot be predicted. In recent years, cyber-attacks and technology malfunctions and failures have become increasingly frequent in this sector and have caused significant losses to companies in this sector, which may negatively impact the Fund. Geographic Risk. A natural disaster could occur in a geographic region in which the Fund or the Underlying Fund invests, which could affect the economy or particular business operations of companies in the specific geographic region, causing an adverse impact on the Fund's or the Underlying Fund's investments in the affected region. Hedging Risk. The Fund seeks to mitigate the potential impact of inflation on the performance of investment-grade corporate bonds by investing in inflation hedging instruments. The Fund’s use of inflation hedging instruments is intended solely to mitigate inflation risk and is not intended to mitigate credit risk, interest rate risk, or other factors influencing the price of investment-grade corporate bonds, which may have a greater impact on the bonds’ returns than inflation. There is no guarantee that the Fund’s positions in inflation hedging instruments will completely eliminate the inflation risk of the long positions in investment-grade corporate bonds. In addition, when interest rates rise above the inflation rate, the Fund’s investments will generally underperform a portfolio comprised solely of the investment-grade corporate bonds. In certain low inflation rate environments, the Fund’s hedging strategy could result in disproportionately larger losses in the positions in inflation hedging instruments as compared to gains in the long investment-grade corporate bond positions attributable to interest rate changes. The Fund only seeks to hedge the impact of inflation and, as a result, if floating interest rates rise above the inflation-linked rates, the Fund will not be hedged. There is no guarantee the Fund will have positive returns, even in environments of sharply rising inflation rates in which the Fund’s positions in inflation hedging instruments might be expected to mitigate the effects of such rises. The Fund will incur expenses when entering into positions in inflation hedging instruments. Moreover, to the extent that inflation risk has been priced into the investment-grade corporate bonds owned by the Fund or the Underlying Fund, the Fund will underperform the Underlying Fund even during inflationary periods. Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund or the Underlying Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, bonds in the Underlying Fund's index are substituted, or the Fund or the Underlying Fund otherwise needs to purchase additional bonds. Industrials Sector Risk. Companies in the industrials sector may be adversely affected by changes in the supply of and demand for products and services, product obsolescence, claims for environmental damage or product liability and changes in general economic conditions, among other factors. Inflation-Linked Instruments Risk. There can be no assurance that the Consumer Price Index (“CPI”), which typically is referenced by inflation swaps, or any other inflation index will accurately measure the rate of inflation experienced in the U.S. or the rate of expected future inflation reflected in the prices and yields of bonds held by the Fund. CPI swaps may cause the Fund’s NAV and returns to be more volatile and expose the Fund to counterparty risk. The Fund could lose money on both the inflation hedging instruments and the investment-grade corporate bonds, and the present value of the Fund’s portfolio investments could decrease if inflation increases. Inflation Risk. The Fund seeks to mitigate many of the adverse impacts of inflation on investment-grade corporate bonds held by the Fund and their issuers primarily through the use of swaps linked to the CPI. The CPI is a measure that examines the weighted average of prices of a basket of consumer goods and services, and measures changes in the purchasing power of the U.S. dollar and the rate of inflation. CPI swaps will not mitigate inflation risk regarding distributions made by the Fund itself. By entering into a CPI swap, the Fund effectively turns the inflation component of the bonds held by the Fund or the Underlying Fund from fixed rates into floating rates. The Fund will lose money on the CPI swap and underperform if inflation is lower than the expected rate being hedged. The Fund will benefit from a CPI swap if actual inflation (as measured by the CPI) during the time period in which the Fund holds the swap is the same or greater than the level of inflation expected for that period. However, if actual inflation (as measured by the CPI) is less than the rate of inflation expected for that period, the Fund generally will lose money on the CPI swap and underperform the Underlying Fund as a result of having entered into the CPI swap. Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund or the Underlying Fund to decline to the extent that the increase is not linked to inflation or the Fund’s hedging strategy is not effectively implemented. Even if the Fund is hedged against losses due to interest rate increases linked to inflation, interest rate increases may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates, such as increases linked to inflation. In order to hedge the risk of interest rate increases due to inflation, the Fund will take positions in inflation hedging instruments. As a result, when the rate of inflation does not increase or when interest rates increase or decrease inversely to changes in the rate of inflation, the Fund will underperform funds with long-only investments in the same investment-grade corporate bonds as the Fund. There is no guarantee that the Fund or Underlying Fund will have positive performance even in environments of sharply rising inflation. There is no guarantee that the Fund or Underlying Fund will be able to successfully mitigate inflation risk or that bond values and interest rates will match changes in inflation rates. Interest Rate Swap Risk. Interest rate swaps are subject to risks applicable to swaps generally, including the risk that a counterparty fails to meet its obligations and the risk that the Fund is not able to liquidate such swap in a timely manner or at all, which could result in losses to the Fund. Because the Fund will invest in swaps that are subject to central clearing, these swaps are subject to the risk that a central clearinghouse will go into bankruptcy or become non-operational, and sometimes involve increased transaction costs. Counterparties to OTC swaps are not subject to these risks. An interest rate swap may fail to perform as intended and may not offset adverse changes in interest rates fully or at all. An interest rate swap may also reduce the Fund’s gains due to favorable changes in interest rates and result in losses to the Fund. Counterparties to interest rate swaps are subject to manipulation in the marketplace of the reference benchmark rate, which may affect the utility of the swap as a hedge. Investment in the Underlying Fund Risk. The Fund expects to invest a substantial portion of its assets in the Underlying Fund, so the Fund’s investment performance is likely to be directly related to the performance of the Underlying Fund, adjusted for the impact of changes in the rate of inflation. The Fund’s NAV will change with changes in the value of the Underlying Fund and other securities and instruments in which the Fund invests based on their market valuations. An investment in the Fund will entail more costs and expenses than a direct investment in the Underlying Fund. As the Fund’s allocations to the Underlying Fund change from time to time, or to the extent that the expense ratio of the Underlying Fund changes, the weighted average operating expenses borne by the Fund may increase or decrease. Through its investment in the Underlying Fund, the Fund is exposed to Management Risk, Market Risk, and Market Trading Risk, among other risks. Issuer Risk. The performance of the Fund depends on the performance of individual instruments to which the Fund or the Underlying Fund has exposure. Changes in the financial condition or credit rating of an issuer of those securities or counterparty on other instruments may cause the value of the securities or instruments to decline. Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. Market Risk. The Fund and the Underlying Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Market Trading Risk. The Fund and the Underlying Fund face numerous market trading risks, including the potential lack of an active market for their shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which an arbitrage mechanism will develop. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. Non-Diversification Risk. The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers. As a result, the Fund's performance may depend on the performance of a small number of issuers. Operational Risk. The Fund and the Underlying Fund are exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s or the Underlying Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund, the Underlying Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks. Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund or the Underlying Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential. Risk of Investing in the U.S. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund or the Underlying Fund has exposure. Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses. Securities Lending Risk. The Fund or the Underlying Fund may engage in securities lending. Securities lending involves the risk that the Fund or the Underlying Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund or the Underlying Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund or Underlying Fund. Small Fund Risk. When the Fund’s size is small, the Fund may experience low trading volume and wide bid/ask spreads. In addition, the Fund may face the risk of being delisted if the Fund does not meet certain conditions of the listing exchange. Tax Risk. The Fund invests in derivatives. The federal income tax treatment of a derivative may not be as favorable as a direct investment in an underlying asset. Derivatives may produce taxable income and taxable realized gain. Derivatives may adversely affect the timing, character and amount of income the Fund realizes from its investments. As a result, a larger portion of the Fund’s distributions may be treated as ordinary income rather than as capital gains. In addition, certain derivatives are subject to mark-to-market or straddle provisions of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). If such provisions are applicable, there could be an increase (or decrease) in the amount of taxable dividends paid by the Fund. Income from swaps is generally taxable. In addition, the tax treatment of certain derivatives, such as swaps, is unsettled and may be subject to future legislation, regulation or administrative pronouncements issued by the U.S. Internal Revenue Service (“IRS”).
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	<b>Non-Diversification Risk.</b> The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers. As a result, the Fund's performance may depend on the performance of a small number of issuers.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>Performance Information</b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	As of the date of the Prospectus, the Fund has been in operation for less than one full calendar year and therefore does not report its performance information.
Performance One Year or Less [Text]	rr_PerformanceOneYearOrLess	As of the date of the Prospectus, the Fund has been in operation for less than one full calendar year and therefore does not report its performance information.
iShares Inflation Hedged Corporate Bond ETF | iShares Inflation Hedged Corporate Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.20%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	none
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.14%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.34%
Fee Waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.15%)
Total Annual Fund Operating Expenses After Fee Waiver	rr_NetExpensesOverAssets	0.19%
1 Year	rr_ExpenseExampleYear01	$ 19
3 Years	rr_ExpenseExampleYear03	$ 61

XML

iShares Interest Rate Hedged Corporate Bond ETF

iSHARES^® INTEREST RATE HEDGED CORPORATE BOND ETF<br/>Ticker: LQDH                                 Stock Exchange: NYSE Arca

<b>Investment Objective </b>

The iShares Interest Rate Hedged Corporate Bond ETF (the “Fund”) seeks to mitigate the interest rate risk of a portfolio composed of U.S. dollar-denominated, investment-grade corporate bonds.

<b>Fees and Expenses </b>

The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”). BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees so that the Fund’s total annual fund operating expenses after fee waiver is equal to the Acquired Fund Fees and Expenses attributable to the Fund’s investment in the iShares iBoxx $ Investment Grade Corporate Bond ETF (“LQD” or the “Underlying Fund”), after taking into account any fee waivers by LQD, plus 0.10% through February 28, 2022. The contractual waiver may be terminated prior to February 28, 2022 only upon written agreement of the Trust and BFA.

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

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

Annual Fund Operating Expenses	Management Fees	Distribution and Service (12b-1) Fees	Other Expenses	Acquired Fund Fees and Expenses	Total Annual Fund Operating Expenses	Fee Waiver	Total Annual Fund Operating Expenses After Fee Waiver
iShares Interest Rate Hedged Corporate Bond ETF | iShares Interest Rate Hedged Corporate Bond ETF	0.30%	none	none	0.15%	0.45%	(0.20%)	0.25%

<b>Example. </b>

This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example	1 Year	3 Years	5 Years	10 Years
iShares Interest Rate Hedged Corporate Bond ETF | iShares Interest Rate Hedged Corporate Bond ETF | USD ($)	26	80	189	505

<b>Portfolio Turnover.</b>

The Fund and the Underlying Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate for the Fund or the Underlying Fund may indicate higher transaction costs and may cause the Fund or the Underlying Fund to incur increased expenses. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example (except costs to the Underlying Fund included as part of Acquired Fund Fees and Expenses), affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 2% of the average value of its portfolio. To the extent the Underlying Fund incurs costs from high portfolio turnover, such costs may have a negative effect on the performance of the Fund.

<b>Principal Investment Strategies </b>

The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in U.S. dollar-denominated investment-grade bonds, in one or more underlying funds that principally invest in investment-grade bonds. The Fund intends to invest a substantial portion of its assets in the Underlying Fund. The Fund attempts to mitigate the interest rate risk of the underlying securities or the Underlying Fund (as determined by BFA) primarily through the use of positions in both U.S. Treasury futures contracts and interest rate swaps (i.e., enter into a contract or contracts in which the Fund will make fixed-rate payments while receiving floating-rate payments based on a reference rate). The Fund may also invest in other interest rate futures contracts, including but not limited to, Eurodollar and Federal Funds futures. The Fund’s futures and interest rate swap positions are not intended to mitigate credit risk or other factors influencing the price of investment-grade corporate bonds, which may have a greater impact than interest rates.

The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index.

The Fund may also invest in other ETFs (including other iShares funds), U.S. government securities, options and swap contracts, short-term paper, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates.

The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index.

The Fund may lend securities representing up to one-third of the value of the Fund's total assets (including the value of the collateral received).

<b>Summary of Principal Risks </b>

As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below (either directly or through its investments in the Underlying Fund), any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF.

Asset Class Risk. Securities and other assets in the Fund's or the Underlying Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes.

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of this Prospectus), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes.

Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund or the Underlying Fund may “call” or repay the security before its stated maturity, and the Fund or the Underlying Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's or Underlying Fund's income, or in securities with greater risks or with other less favorable features.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's or the Underlying Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class.

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

Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s or Underlying Fund's investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation.

Cyber Security Risk. Failures or breaches of the electronic systems of the Fund or the Underlying Fund, the Fund's or the Underlying Fund's adviser, distributor, or other service providers (including the benchmark provider), market makers, Authorized Participants, hedging counterparties to the Fund or the issuers of securities in which the Fund or the Underlying Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants, hedging counterparties to the Fund or issuers of securities in which the Fund or the Underlying Fund invests.

Derivatives Risk. The Fund’s or Underlying Fund's use of derivatives may reduce the Fund’s or Underlying Fund's returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Counterparty risk for over-the-counter (“OTC”) derivatives is generally higher than that for derivatives traded on an exchange or through a clearing house. A risk of the Fund’s or Underlying Fund's use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund or Underlying Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund or Underlying Fund to sell or otherwise close a derivatives position could expose the Fund or Underlying Fund to losses and could make derivatives more difficult for the Fund or Underlying Fund to value accurately. The Fund or Underlying Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund or Underlying Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund or Underlying Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund or Underlying Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund or Underlying Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives.

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

Financials Sector Risk. Performance of companies in the financials sector may be adversely impacted by many factors, including, among others, changes in government regulations, economic conditions, and interest rates, credit rating downgrades, and decreased liquidity in credit markets. The extent to which the Fund may invest in a company that engages in securities-related activities or banking is limited by applicable law. The impact of changes in capital requirements and recent or future regulation of any individual financial company, or of the financials sector as a whole, cannot be predicted. In recent years, cyber-attacks and technology malfunctions and failures have become increasingly frequent in this sector and have caused significant losses to companies in this sector, which may negatively impact the Fund.

Geographic Risk. A natural disaster could occur in a geographic region in which the Fund or the Underlying Fund invests, which could affect the economy or particular business operations of companies in the specific geographic region, causing an adverse impact on the Fund's or the Underlying Fund's investments in the affected region.

Hedging Risk. The Fund seeks to mitigate the potential impact of interest rates on the performance of investment-grade bonds by entering into positions in U.S. Treasury and other futures and interest rate swaps. The Fund’s Treasury and other futures positions are not intended to mitigate credit risk or other factors influencing the price of investment-grade bonds, which may have a greater impact than interest rates. There is no guarantee that the Fund’s Treasury and other futures and interest rate swap positions will completely eliminate the interest rate risk of the long positions in investment-grade bonds. In addition, when interest rates fall, long–only investment-grade bond investments will perform better than the Fund’s investments. In certain falling interest rate environments, the Fund’s hedging strategy could result in disproportionately larger losses in the Treasury and other futures and interest rate swap positions as compared to gains in the long investment-grade bond positions attributable to interest rate changes. There is no guarantee the Fund will have positive returns, even in environments of sharply rising interest rates in which the Fund’s Treasury and other futures and interest rate swap positions might be expected to mitigate the effects of such rises. The Fund will incur expenses when entering into Treasury and other futures and interest rate swap positions.

Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices.

Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund or the Underlying Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, bonds in the Underlying Fund's index are substituted, or the Fund or the Underlying Fund otherwise needs to purchase additional bonds.

Industrials Sector Risk. Companies in the industrials sector may be adversely affected by changes in the supply of and demand for products and services, product obsolescence, claims for environmental damage or product liability and changes in general economic conditions, among other factors.

Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund or the Underlying Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. The Fund will take positions in Treasury and other futures and interest rate swaps. As a result, when interest rates decline, the Fund will underperform funds with long-only investments in the same investment-grade bonds as the Fund. There is no guarantee that the Fund or Underlying Fund will have positive performance even in environments of sharply rising interest rates. There is no guarantee that the Fund or Underlying Fund will be able to successfully mitigate interest rate risk.

Interest Rate Swap Risk. Interest rate swaps are subject to risks applicable to swaps generally, including the risk that a counterparty fails to meet its obligations and the risk that the Fund is not able to liquidate such swap in a timely manner or at all, which could result in losses to the Fund. Because the Fund will invest in swaps that are subject to central clearing, these swaps are subject to the risk that a central clearinghouse will go into bankruptcy or become non-operational, and sometimes involve increased transaction costs. Counterparties to OTC swaps are not subject to these risks. An interest rate swap may fail to perform as intended and may not offset adverse changes in interest rates fully or at all. An interest rate swap may also reduce the Fund’s gains due to favorable changes in interest rates and result in losses to the Fund. Counterparties to interest rate swaps are subject to manipulation in the marketplace of the reference benchmark rate, which may affect the utility of the swap as a hedge.

Investment in the Underlying Fund Risk. The Fund expects to invest a substantial portion of its assets in the Underlying Fund, so the Fund’s investment performance is likely to be directly related to the performance of the Underlying Fund. The Fund’s NAV will change with changes in the value of the Underlying Fund and other securities and instruments in which the Fund invests based on their market valuations. An investment in the Fund will entail more costs and expenses than a direct investment in the Underlying Fund.

As the Fund’s allocations to the Underlying Fund change from time to time, or to the extent that the expense ratio of the Underlying Fund changes, the weighted average operating expenses borne by the Fund may increase or decrease.

Through its investment in the Underlying Fund, the Fund is exposed to Management Risk, Market Risk, and Market Trading Risk, among other risks.

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

Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective.

Market Risk. The Fund and the Underlying Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns.

Market Trading Risk. The Fund and the Underlying Fund face numerous market trading risks, including the potential lack of an active market for their shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's or Underlying Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S AND THE UNDERLYING FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

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

Operational Risk. The Fund and the Underlying Fund are exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s or the Underlying Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund, the Underlying Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund or the Underlying Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential.

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

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

Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses.

Securities Lending Risk. The Fund or the Underlying Fund may engage in securities lending. Securities lending involves the risk that the Fund or the Underlying Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund or the Underlying Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund or Underlying Fund.

Tax Risk. The Underlying Fund invests in derivatives. The federal income tax treatment of a derivative may not be as favorable as a direct investment in an underlying asset. Derivatives may produce taxable income and taxable realized gain. Derivatives may adversely affect the timing, character and amount of income the Underlying Fund realizes from its investments. As a result, a larger portion of the Fund’s distributions may be treated as ordinary income rather than as capital gains. In addition, certain derivatives are subject to mark-to-market or straddle provisions of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). If such provisions are applicable, there could be an increase (or decrease) in the amount of taxable dividends paid by the Fund. Income from swaps is generally taxable. In addition, the tax treatment of certain derivatives, such as swaps, is unsettled and may be subject to future legislation, regulation or administrative pronouncements issued by the U.S. Internal Revenue Service (“IRS”).

<b>Performance Information </b>

The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.

<b>Year by Year Returns (Years Ended December 31) </b>

The best calendar quarter return during the periods shown above was 2.41% in the 3rd quarter of 2018; the worst was -3.65% in the 4th quarter of 2018.

Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).

<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>

Average Annual Total Returns - iShares Interest Rate Hedged Corporate Bond ETF		One Year	Since Fund Inception	Inception Date
iShares Interest Rate Hedged Corporate Bond ETF		(1.79%)	1.05%	May 27, 2014
iShares Interest Rate Hedged Corporate Bond ETF | Return After Taxes on Distributions	[1]	(3.43%)	(0.23%)
iShares Interest Rate Hedged Corporate Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares	[1]	(0.75%)	0.27%
Markit iBoxx USD Liquid Investment Grade Interest Rate Hedged Swaps Index (Index returns do not reflect deductions for fees, expenses, or taxes)	[2]	(1.47%)	1.84%

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[2] The Markit iBoxx USD Liquid Investment Grade Interest Rate Hedged Swaps Index is an unmanaged index that is designed to reflect the duration hedged performance of U.S. dollar-denominated investment-grade corporate debt.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	iShares U.S. ETF Trust
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
iShares Interest Rate Hedged Corporate Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	iSHARES<sup>®</sup> INTEREST RATE HEDGED CORPORATE BOND ETF<br/>Ticker: LQDH                                 Stock Exchange: NYSE Arca
Objective [Heading]	rr_ObjectiveHeading	<b>Investment Objective </b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The iShares Interest Rate Hedged Corporate Bond ETF (the “Fund”) seeks to mitigate the interest rate risk of a portfolio composed of U.S. dollar-denominated, investment-grade corporate bonds.
Expense [Heading]	rr_ExpenseHeading	<b>Fees and Expenses </b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”). BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees so that the Fund’s total annual fund operating expenses after fee waiver is equal to the Acquired Fund Fees and Expenses attributable to the Fund’s investment in the iShares iBoxx $ Investment Grade Corporate Bond ETF (“LQD” or the “Underlying Fund”), after taking into account any fee waivers by LQD, plus 0.10% through February 28, 2022. The contractual waiver may be terminated prior to February 28, 2022 only upon written agreement of the Trust and BFA. You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>Annual Fund Operating Expenses<br/>(ongoing expenses that you pay each year as a<br/>percentage of the value of your investments)</b>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	February 28, 2022
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>Portfolio Turnover.</b>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund and the Underlying Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate for the Fund or the Underlying Fund may indicate higher transaction costs and may cause the Fund or the Underlying Fund to incur increased expenses. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example (except costs to the Underlying Fund included as part of Acquired Fund Fees and Expenses), affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 2% of the average value of its portfolio. To the extent the Underlying Fund incurs costs from high portfolio turnover, such costs may have a negative effect on the performance of the Fund.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	2.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”).
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>Example. </b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>Principal Investment Strategies </b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in U.S. dollar-denominated investment-grade bonds, in one or more underlying funds that principally invest in investment-grade bonds. The Fund intends to invest a substantial portion of its assets in the Underlying Fund. The Fund attempts to mitigate the interest rate risk of the underlying securities or the Underlying Fund (as determined by BFA) primarily through the use of positions in both U.S. Treasury futures contracts and interest rate swaps (i.e., enter into a contract or contracts in which the Fund will make fixed-rate payments while receiving floating-rate payments based on a reference rate). The Fund may also invest in other interest rate futures contracts, including but not limited to, Eurodollar and Federal Funds futures. The Fund’s futures and interest rate swap positions are not intended to mitigate credit risk or other factors influencing the price of investment-grade corporate bonds, which may have a greater impact than interest rates. The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index. The Fund may also invest in other ETFs (including other iShares funds), U.S. government securities, options and swap contracts, short-term paper, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates. The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index. The Fund may lend securities representing up to one-third of the value of the Fund's total assets (including the value of the collateral received).
Risk [Heading]	rr_RiskHeading	<b>Summary of Principal Risks </b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below (either directly or through its investments in the Underlying Fund), any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF. Asset Class Risk. Securities and other assets in the Fund's or the Underlying Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes. Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of this Prospectus), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes. Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund or the Underlying Fund may “call” or repay the security before its stated maturity, and the Fund or the Underlying Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's or Underlying Fund's income, or in securities with greater risks or with other less favorable features. Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's or the Underlying Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. Consumer Staples Sector Risk. The consumer staples sector may be affected by, among other things, marketing campaigns, changes in consumer demands, government regulations and changes in commodity prices. Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s or Underlying Fund's investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation. Cyber Security Risk. Failures or breaches of the electronic systems of the Fund or the Underlying Fund, the Fund's or the Underlying Fund's adviser, distributor, or other service providers (including the benchmark provider), market makers, Authorized Participants, hedging counterparties to the Fund or the issuers of securities in which the Fund or the Underlying Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants, hedging counterparties to the Fund or issuers of securities in which the Fund or the Underlying Fund invests. Derivatives Risk. The Fund’s or Underlying Fund's use of derivatives may reduce the Fund’s or Underlying Fund's returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Counterparty risk for over-the-counter (“OTC”) derivatives is generally higher than that for derivatives traded on an exchange or through a clearing house. A risk of the Fund’s or Underlying Fund's use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund or Underlying Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund or Underlying Fund to sell or otherwise close a derivatives position could expose the Fund or Underlying Fund to losses and could make derivatives more difficult for the Fund or Underlying Fund to value accurately. The Fund or Underlying Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund or Underlying Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund or Underlying Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund or Underlying Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund or Underlying Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives. Extension Risk. During periods of rising interest rates, certain debt obligations may be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in the Fund’s or the Underlying Fund's income and potentially in the value of the Fund’s or an Underlying Fund's investments. Financials Sector Risk. Performance of companies in the financials sector may be adversely impacted by many factors, including, among others, changes in government regulations, economic conditions, and interest rates, credit rating downgrades, and decreased liquidity in credit markets. The extent to which the Fund may invest in a company that engages in securities-related activities or banking is limited by applicable law. The impact of changes in capital requirements and recent or future regulation of any individual financial company, or of the financials sector as a whole, cannot be predicted. In recent years, cyber-attacks and technology malfunctions and failures have become increasingly frequent in this sector and have caused significant losses to companies in this sector, which may negatively impact the Fund. Geographic Risk. A natural disaster could occur in a geographic region in which the Fund or the Underlying Fund invests, which could affect the economy or particular business operations of companies in the specific geographic region, causing an adverse impact on the Fund's or the Underlying Fund's investments in the affected region. Hedging Risk. The Fund seeks to mitigate the potential impact of interest rates on the performance of investment-grade bonds by entering into positions in U.S. Treasury and other futures and interest rate swaps. The Fund’s Treasury and other futures positions are not intended to mitigate credit risk or other factors influencing the price of investment-grade bonds, which may have a greater impact than interest rates. There is no guarantee that the Fund’s Treasury and other futures and interest rate swap positions will completely eliminate the interest rate risk of the long positions in investment-grade bonds. In addition, when interest rates fall, long–only investment-grade bond investments will perform better than the Fund’s investments. In certain falling interest rate environments, the Fund’s hedging strategy could result in disproportionately larger losses in the Treasury and other futures and interest rate swap positions as compared to gains in the long investment-grade bond positions attributable to interest rate changes. There is no guarantee the Fund will have positive returns, even in environments of sharply rising interest rates in which the Fund’s Treasury and other futures and interest rate swap positions might be expected to mitigate the effects of such rises. The Fund will incur expenses when entering into Treasury and other futures and interest rate swap positions. Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund or the Underlying Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, bonds in the Underlying Fund's index are substituted, or the Fund or the Underlying Fund otherwise needs to purchase additional bonds. Industrials Sector Risk. Companies in the industrials sector may be adversely affected by changes in the supply of and demand for products and services, product obsolescence, claims for environmental damage or product liability and changes in general economic conditions, among other factors. Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund or the Underlying Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. The Fund will take positions in Treasury and other futures and interest rate swaps. As a result, when interest rates decline, the Fund will underperform funds with long-only investments in the same investment-grade bonds as the Fund. There is no guarantee that the Fund or Underlying Fund will have positive performance even in environments of sharply rising interest rates. There is no guarantee that the Fund or Underlying Fund will be able to successfully mitigate interest rate risk. Interest Rate Swap Risk. Interest rate swaps are subject to risks applicable to swaps generally, including the risk that a counterparty fails to meet its obligations and the risk that the Fund is not able to liquidate such swap in a timely manner or at all, which could result in losses to the Fund. Because the Fund will invest in swaps that are subject to central clearing, these swaps are subject to the risk that a central clearinghouse will go into bankruptcy or become non-operational, and sometimes involve increased transaction costs. Counterparties to OTC swaps are not subject to these risks. An interest rate swap may fail to perform as intended and may not offset adverse changes in interest rates fully or at all. An interest rate swap may also reduce the Fund’s gains due to favorable changes in interest rates and result in losses to the Fund. Counterparties to interest rate swaps are subject to manipulation in the marketplace of the reference benchmark rate, which may affect the utility of the swap as a hedge. Investment in the Underlying Fund Risk. The Fund expects to invest a substantial portion of its assets in the Underlying Fund, so the Fund’s investment performance is likely to be directly related to the performance of the Underlying Fund. The Fund’s NAV will change with changes in the value of the Underlying Fund and other securities and instruments in which the Fund invests based on their market valuations. An investment in the Fund will entail more costs and expenses than a direct investment in the Underlying Fund. As the Fund’s allocations to the Underlying Fund change from time to time, or to the extent that the expense ratio of the Underlying Fund changes, the weighted average operating expenses borne by the Fund may increase or decrease. Through its investment in the Underlying Fund, the Fund is exposed to Management Risk, Market Risk, and Market Trading Risk, among other risks. Issuer Risk. The performance of the Fund depends on the performance of individual instruments to which the Fund or the Underlying Fund has exposure. Changes in the financial condition or credit rating of an issuer of those securities or counterparty on other instruments may cause the value of the securities or instruments to decline. Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. Market Risk. The Fund and the Underlying Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Market Trading Risk. The Fund and the Underlying Fund face numerous market trading risks, including the potential lack of an active market for their shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's or Underlying Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S AND THE UNDERLYING FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. Non-U.S. Issuers Risk. Securities issued by non-U.S. issuers carry different risks from securities issued by U.S. issuers. These risks include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or confiscatory taxation, adverse changes in investment or exchange control regulations, political instability, regulatory and economic differences, and potential restrictions on the flow of international capital. Operational Risk. The Fund and the Underlying Fund are exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s or the Underlying Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund, the Underlying Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks. Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund or the Underlying Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential. Risk of Investing in Developed Countries. The Fund’s and the Underlying Fund's investment in developed country issuers may subject the Fund to regulatory, political, currency, security, economic and other risks associated with developed countries. Developed countries tend to represent a significant portion of the global economy and have generally experienced slower economic growth than some less developed countries. Certain developed countries have experienced security concerns, such as terrorism and strained international relations. Incidents involving a country’s or region’s security may cause uncertainty in its markets and may adversely affect its economy and the Fund’s or the Underlying Fund's investments. In addition, developed countries may be adversely impacted by changes to the economic conditions of certain key trading partners, regulatory burdens, debt burdens and the price or availability of certain commodities. Risk of Investing in the U.S. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund or the Underlying Fund has exposure. Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses. Securities Lending Risk. The Fund or the Underlying Fund may engage in securities lending. Securities lending involves the risk that the Fund or the Underlying Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund or the Underlying Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund or Underlying Fund. Tax Risk. The Underlying Fund invests in derivatives. The federal income tax treatment of a derivative may not be as favorable as a direct investment in an underlying asset. Derivatives may produce taxable income and taxable realized gain. Derivatives may adversely affect the timing, character and amount of income the Underlying Fund realizes from its investments. As a result, a larger portion of the Fund’s distributions may be treated as ordinary income rather than as capital gains. In addition, certain derivatives are subject to mark-to-market or straddle provisions of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). If such provisions are applicable, there could be an increase (or decrease) in the amount of taxable dividends paid by the Fund. Income from swaps is generally taxable. In addition, the tax treatment of certain derivatives, such as swaps, is unsettled and may be subject to future legislation, regulation or administrative pronouncements issued by the U.S. Internal Revenue Service (“IRS”).
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>Performance Information </b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-800-iShares (1-800-474-2737) (toll free)
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.iShares.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>Year by Year Returns (Years Ended December 31) </b>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The best calendar quarter return during the periods shown above was 2.41% in the 3rd quarter of 2018; the worst was -3.65% in the 4th quarter of 2018. Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).
Performance Table Heading	rr_PerformanceTableHeading	<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”).
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.
iShares Interest Rate Hedged Corporate Bond ETF | iShares Interest Rate Hedged Corporate Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.30%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	none
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.15%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.45%
Fee Waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.20%)
Total Annual Fund Operating Expenses After Fee Waiver	rr_NetExpensesOverAssets	0.25%
1 Year	rr_ExpenseExampleYear01	$ 26
3 Years	rr_ExpenseExampleYear03	80
5 Years	rr_ExpenseExampleYear05	189
10 Years	rr_ExpenseExampleYear10	$ 505
2015	rr_AnnualReturn2015	(2.39%)
2016	rr_AnnualReturn2016	5.21%
2017	rr_AnnualReturn2017	6.16%
2018	rr_AnnualReturn2018	(1.79%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	best
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2018
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	2.41%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	worst
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2018
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(3.65%)
One Year	rr_AverageAnnualReturnYear01	(1.79%)
Since Fund Inception	rr_AverageAnnualReturnSinceInception	1.05%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 27, 2014
iShares Interest Rate Hedged Corporate Bond ETF | Return After Taxes on Distributions | iShares Interest Rate Hedged Corporate Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(3.43%)	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	(0.23%)	[1]
iShares Interest Rate Hedged Corporate Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares | iShares Interest Rate Hedged Corporate Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(0.75%)	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	0.27%	[1]
iShares Interest Rate Hedged Corporate Bond ETF | Markit iBoxx USD Liquid Investment Grade Interest Rate Hedged Swaps Index (Index returns do not reflect deductions for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(1.47%)	[2]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	1.84%	[2]

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[2] The Markit iBoxx USD Liquid Investment Grade Interest Rate Hedged Swaps Index is an unmanaged index that is designed to reflect the duration hedged performance of U.S. dollar-denominated investment-grade corporate debt.

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iShares Interest Rate Hedged Emerging Markets Bond ETF

iSHARES^® INTEREST RATE HEDGED EMERGING MARKETS BOND ETF<br/>Ticker: EMBH                                 Stock Exchange: NYSE Arca

<b>Investment Objective </b>

The iShares Interest Rate Hedged Emerging Markets Bond ETF (the “Fund”) seeks to mitigate the interest rate risk of a portfolio composed of U.S. dollar-denominated, emerging market bonds.

<b>Fees and Expenses </b>

The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”). BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees so that the Fund’s total annual fund operating expenses after fee waiver is equal to the Acquired Fund Fees and Expenses attributable to the Fund’s investment in the iShares J.P. Morgan USD Emerging Markets Bond ETF (“EMB” or the “Underlying Fund”), after taking into account any fee waivers by EMB, plus 0.10% through February 28, 2022. The contractual waiver may be terminated prior to February 28, 2022 only upon written agreement of the Trust and BFA.

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

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

Annual Fund Operating Expenses	Management Fees	Distribution and Service (12b-1) Fees	Other Expenses	Acquired Fund Fees and Expenses	Total Annual Fund Operating Expenses	Fee Waiver	Total Annual Fund Operating Expenses After Fee Waiver
iShares Interest Rate Hedged Emerging Markets Bond ETF | iShares Interest Rate Hedged Emerging Markets Bond ETF	0.75%	none	none	0.38%	1.13%	(0.65%)	0.48%

<b>Example. </b>

This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example	1 Year	3 Years	5 Years	10 Years
iShares Interest Rate Hedged Emerging Markets Bond ETF | iShares Interest Rate Hedged Emerging Markets Bond ETF | USD ($)	49	154	422	1,189

<b>Portfolio Turnover.</b>

The Fund and the Underlying Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate for the Fund or the Underlying Fund may indicate higher transaction costs and may cause the Fund or the Underlying Fund to incur increased expenses. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example (except costs to the Underlying Fund included as part of Acquired Fund Fees and Expenses), affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 0% of the average value of its portfolio. To the extent the Underlying Fund incurs costs from high portfolio turnover, such costs may have a negative effect on the performance of the Fund.

<b>Principal Investment Strategies </b>

The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in U.S. dollar-denominated emerging market bonds, in one or more underlying funds that principally invest in emerging market bonds. The Fund intends to invest a substantial portion of its assets in one underlying fund, the Underlying Fund. The Fund attempts to mitigate the interest rate risk of the underlying securities and/or the Underlying Fund (as determined by BFA) primarily through the use of positions in both U.S. Treasury futures contracts and interest rate swaps (i.e., enter into a contract or contracts in which the Fund will make fixed-rate payments while receiving floating-rate payments based on a reference rate). The bonds in which the Fund and/or the Underlying Fund invest may include both investment-grade and non-investment-grade bonds and generally have at least two years until maturity at the time of investment. The Fund may also invest in other interest rate futures contracts, including but not limited to, Eurodollar and Federal Funds futures. The Fund’s futures and interest rate swap positions are not intended to mitigate credit risk or other factors influencing the price of emerging market bonds, which may have a greater impact than interest rates.

The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index.

The Fund may also invest in other ETFs (including other iShares funds), U.S. government securities, options and swap contracts, short-term paper, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates.

The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index.

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).

<b>Summary of Principal Risks </b>

As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below (either directly or through its investments in the Underlying Fund), any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF.

Asset Class Risk. Securities and other assets in the Fund's or the Underlying Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes.

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

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of the Prospectus), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes.

Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund or the Underlying Fund may “call” or repay the security before its stated maturity, and the Fund or the Underlying Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's or Underlying Fund's income, or in securities with greater risks or with other less favorable features.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's or the Underlying Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class.

Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s or Underlying Fund's investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation.

Custody Risk. Less developed securities markets are more likely to experience problems with the clearing and settling of trades, as well as the holding of securities by local banks, agents and depositories.

Cyber Security Risk. Failures or breaches of the electronic systems of the Fund or the Underlying Fund, the Fund's or the Underlying Fund's adviser, distributor, or other service providers (including the benchmark provider), market makers, Authorized Participants, hedging counterparties to the Fund or the issuers of securities in which the Fund or the Underlying Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants, hedging counterparties to the Fund or issuers of securities in which the Fund or the Underlying Fund invests.

Derivatives Risk. The Fund’s or Underlying Fund's use of derivatives may reduce the Fund’s or Underlying Fund's returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Counterparty risk for over-the-counter (“OTC”) derivatives is generally higher than that for derivatives traded on an exchange or through a clearing house. A risk of the Fund’s or Underlying Fund's use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund or Underlying Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund or Underlying Fund to sell or otherwise close a derivatives position could expose the Fund or Underlying Fund to losses and could make derivatives more difficult for the Fund or Underlying Fund to value accurately. The Fund or Underlying Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund or Underlying Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund or Underlying Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund or Underlying Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund or Underlying Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives.

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

Geographic Risk. A natural disaster could occur in a geographic region in which the Fund or the Underlying Fund invests, which could affect the economy or particular business operations of companies in the specific geographic region, causing an adverse impact on the Fund's or the Underlying Fund's investments in the affected region.

Hedging Risk. The Fund seeks to mitigate the potential impact of interest rates on the performance of emerging market bonds by entering into positions in U.S. Treasury and other futures and interest rate swaps. The Fund’s Treasury and other futures positions are not intended to mitigate credit risk or other factors influencing the price of emerging market bonds, which may have a greater impact than interest rates. There is no guarantee that the Fund’s Treasury and other futures and interest rate swap positions will completely eliminate the interest rate risk of the long positions in emerging market bonds. In addition, when interest rates fall, long–only emerging market bond investments will perform better than the Fund’s investments. In certain falling interest rate environments, the Fund’s hedging strategy could result in disproportionately larger losses in the Treasury and other futures and interest rate swap positions as compared to gains in the long emerging market bond positions attributable to interest rate changes. There is no guarantee the Fund will have positive returns, even in environments of sharply rising interest rates in which the Fund’s Treasury and other futures and interest rate swap positions might be expected to mitigate the effects of such rises. The Fund will incur expenses when entering into Treasury and other futures and interest rate swap positions.

High Yield Securities Risk. Securities that are rated below investment-grade (commonly referred to as “junk bonds,” which may include those bonds rated below “BBB-” by S&P Global Ratings and Fitch Ratings, Inc. (“Fitch”) or “Baa3” by Moody's Investors Service, Inc. (“Moody's”)), or are unrated, may be deemed speculative, may involve greater levels of risk than higher-rated securities of similar maturity and may be more likely to default.

Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices.

Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund or the Underlying Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, bonds in the Underlying Fund's index are substituted, or the Fund or the Underlying Fund otherwise needs to purchase additional bonds.

Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund or the Underlying Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. The Fund will take positions in Treasury and other futures and interest rate swaps. As a result, when interest rates decline, the Fund will underperform funds with long-only investments in the same emerging market bonds as the Fund. There is no guarantee that the Fund or Underlying Fund will have positive performance even in environments of sharply rising interest rates. There is no guarantee that the Fund or Underlying Fund will be able to successfully mitigate interest rate risk.

Interest Rate Swap Risk. Interest rate swaps are subject to risks applicable to swaps generally, including the risk that a counterparty fails to meet its obligations and the risk that the Fund is not able to liquidate such swap in a timely manner or at all, which could result in losses to the Fund. Because the Fund will invest in swaps that are subject to central clearing, these swaps are subject to the risk that a central clearinghouse will go into bankruptcy or become non-operational, and sometimes involve increased transaction costs. Counterparties to OTC swaps are not subject to these risks. An interest rate swap may fail to perform as intended and may not offset adverse changes in interest rates fully or at all. An interest rate swap may also reduce the Fund’s gains due to favorable changes in interest rates and result in losses to the Fund. Counterparties to interest rate swaps are subject to manipulation in the marketplace of the reference benchmark rate, which may affect the utility of the swap as a hedge.

Investment in the Underlying Fund Risk. The Fund expects to invest a substantial portion of its assets in the Underlying Fund, so the Fund’s investment performance is likely to be directly related to the performance of the Underlying Fund. The Fund’s NAV will change with changes in the value of the Underlying Fund and other securities and instruments in which the Fund invests based on their market valuations. An investment in the Fund will entail more costs and expenses than a direct investment in the Underlying Fund.

As the Fund’s allocations to the Underlying Fund change from time to time, or to the extent that the expense ratio of the Underlying Fund changes, the weighted average operating expenses borne by the Fund may increase or decrease.

Through its investment in the Underlying Fund, the Fund is exposed to Management Risk, Market Risk, and Market Trading Risk, among other risks.

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

Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective.

Market Risk. The Fund and the Underlying Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns.

Market Trading Risk. The Fund and the Underlying Fund face numerous market trading risks, including the potential lack of an active market for their shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's or Underlying Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S AND THE UNDERLYING FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

Non-U.S. Agency Debt Risk. The Fund invests in uncollateralized bonds issued by agencies, subdivisions or instrumentalities of foreign governments. Bonds issued by foreign government agencies, subdivisions or instrumentalities are generally backed only by the general creditworthiness and reputation of the entity issuing the bonds and may not be backed by the full faith and credit of the foreign government. Moreover, a foreign government that explicitly provides its full faith and credit to a particular entity may be, due to changed circumstances, unable or unwilling to provide that support. A non-U.S. agency’s operations and financial condition are influenced by the foreign government’s economic and other policies.

Non-U.S. Issuers Risk. Securities issued by non-U.S. issuers carry different risks from securities issued by U.S. issuers. These risks include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or confiscatory taxation, adverse changes in investment or exchange control regulations, political instability, regulatory and economic differences, and potential restrictions on the flow of international capital. The Fund is specifically exposed to Asian Economic Risk, Central and South American Economic Risk, Eastern European Economic Risk and Middle Eastern Economic Risk.

Operational Risk. The Fund or the Underlying Fund are exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s or the Underlying Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund, the Underlying Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund or the Underlying Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential.

Privately-Issued Securities Risk. The Fund or the Underlying Fund will 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”). Privately-issued securities are securities that have not been registered under the 1933 Act and as a result may be subject to legal restrictions on resale. Privately-issued securities are generally not traded on established markets. As a result of the absence of a public trading market, privately issued securities may be deemed to be illiquid investments, may be more difficult to value than publicly traded securities and may be subject to wide fluctuations in value. Delay or difficulty in selling such securities may result in a loss to the Fund.

Privatization Risk. Some countries in which the Fund or an Underlying Fund invests have privatized, or have begun the process of privatizing, certain entities and industries. Privatized entities may lose money or be re-nationalized.

Reliance on Trading Partners Risk. The Fund or the Underlying Fund invests in countries or regions whose economies are heavily dependent upon trading with key partners. Any reduction in this trading may have an adverse impact on the Fund's investments. Through its holdings of securities of certain issuers, the Fund is specifically exposed to Asian Economic Risk, Central and South American Economic Risk, European Economic Risk and U.S. Economic Risk.

Risk of Investing in Emerging Markets. Investments in emerging market issuers may be subject to a greater risk of loss than investments in issuers located or operating in more developed markets. Emerging markets may be more likely to experience inflation, political turmoil and rapid changes in economic conditions than more developed markets. Emerging markets often have less uniformity in accounting and reporting requirements, less reliable securities valuations and greater risk associated with custody of securities than developed markets.

Risk of Investing in Russia. Investing in Russian securities involves significant risks, including legal, regulatory and economic risks that are specific to Russia. In addition, investing in Russian securities involves risks associated with the settlement of portfolio transactions and loss of the Fund’s ownership rights in its portfolio securities as a result of the system of share registration and custody in Russia. A number of jurisdictions, including the U.S., Canada and the European Union (the “EU”), have imposed economic sanctions on certain Russian individuals and Russian corporate entities. These and future sanctions, or even the threat of further sanctions, may adversely affect Russia’s economy and the Fund’s or the Underlying Fund's investments.

Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses.

Securities Lending Risk. The Fund or the Underlying Fund may engage in securities lending. Securities lending involves the risk that the Fund or the Underlying Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund or the Underlying Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund or Underlying Fund.

Small Fund Risk. When the Fund’s size is small, the Fund may experience low trading volume and wide bid/ask spreads. In addition, the Fund may face the risk of being delisted if the Fund does not meet certain conditions of the listing exchange.

Sovereign and Quasi-Sovereign Obligations Risk. The Fund or the Underlying Fund may invest in securities issued by or guaranteed by sovereign governments and by entities affiliated with or backed by non-U.S. sovereign governments, which may be unable or unwilling to repay principal or interest when due. In times of economic uncertainty, the prices of these securities may be more volatile than those of corporate debt obligations or of other government debt obligations.

Structural Risk. The countries in which the Fund or the Underlying Fund invests may be subject to considerable degrees of economic, political and social instability.

Tax Risk. Because the Fund invests in the Underlying Fund, the Fund’s realized losses on sales of shares of the Underlying Fund may be indefinitely or permanently deferred as “wash sales.” Distributions of short-term capital gains by the Underlying Fund will be recognized as ordinary income by the Fund and would not be offset by the Fund’s capital loss carryforwards, if any. Capital loss carryforwards of the Underlying Fund, if any, would not offset net capital gains of the Fund. Each of these effects is caused by the Fund’s investment in the Underlying Fund and may result in distributions to Fund shareholders being of higher magnitude and less likely to qualify for lower capital gain tax rates than if the Fund were to invest directly in the securities and other instruments comprising its portfolio.

<b>Performance Information </b>

The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.

<b>Year by Year Returns (Years Ended December 31)</b>

The best calendar quarter return during the periods shown above was 3.83% in the 1st quarter of 2017; the worst was -3.84% in the 4th quarter of 2018.

Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).

<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>

Average Annual Total Returns - iShares Interest Rate Hedged Emerging Markets Bond ETF		One Year	Since Fund Inception	Inception Date
iShares Interest Rate Hedged Emerging Markets Bond ETF		(3.77%)	3.29%	Jul. 22, 2015
iShares Interest Rate Hedged Emerging Markets Bond ETF | Return After Taxes on Distributions	[1]	(5.68%)	1.50%
iShares Interest Rate Hedged Emerging Markets Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares	[1]	(2.21%)	1.72%
J.P. Morgan EMBI Global Core Swap Hedged Index (Index returns do not reflect deductions for fees, expenses, or taxes)		(3.61%)	3.57%

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	iShares U.S. ETF Trust
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
iShares Interest Rate Hedged Emerging Markets Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	iSHARES<sup>®</sup> INTEREST RATE HEDGED EMERGING MARKETS BOND ETF<br/>Ticker: EMBH                                 Stock Exchange: NYSE Arca
Objective [Heading]	rr_ObjectiveHeading	<b>Investment Objective </b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The iShares Interest Rate Hedged Emerging Markets Bond ETF (the “Fund”) seeks to mitigate the interest rate risk of a portfolio composed of U.S. dollar-denominated, emerging market bonds.
Expense [Heading]	rr_ExpenseHeading	<b>Fees and Expenses </b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”). BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees so that the Fund’s total annual fund operating expenses after fee waiver is equal to the Acquired Fund Fees and Expenses attributable to the Fund’s investment in the iShares J.P. Morgan USD Emerging Markets Bond ETF (“EMB” or the “Underlying Fund”), after taking into account any fee waivers by EMB, plus 0.10% through February 28, 2022. The contractual waiver may be terminated prior to February 28, 2022 only upon written agreement of the Trust and BFA. You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>Annual Fund Operating Expenses<br/>(ongoing expenses that you pay each year as a<br/>percentage of the value of your investments)</b>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	February 28, 2022
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>Portfolio Turnover.</b>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund and the Underlying Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate for the Fund or the Underlying Fund may indicate higher transaction costs and may cause the Fund or the Underlying Fund to incur increased expenses. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example (except costs to the Underlying Fund included as part of Acquired Fund Fees and Expenses), affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 0% of the average value of its portfolio. To the extent the Underlying Fund incurs costs from high portfolio turnover, such costs may have a negative effect on the performance of the Fund.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	none
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”).
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>Example. </b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>Principal Investment Strategies </b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in U.S. dollar-denominated emerging market bonds, in one or more underlying funds that principally invest in emerging market bonds. The Fund intends to invest a substantial portion of its assets in one underlying fund, the Underlying Fund. The Fund attempts to mitigate the interest rate risk of the underlying securities and/or the Underlying Fund (as determined by BFA) primarily through the use of positions in both U.S. Treasury futures contracts and interest rate swaps (i.e., enter into a contract or contracts in which the Fund will make fixed-rate payments while receiving floating-rate payments based on a reference rate). The bonds in which the Fund and/or the Underlying Fund invest may include both investment-grade and non-investment-grade bonds and generally have at least two years until maturity at the time of investment. The Fund may also invest in other interest rate futures contracts, including but not limited to, Eurodollar and Federal Funds futures. The Fund’s futures and interest rate swap positions are not intended to mitigate credit risk or other factors influencing the price of emerging market bonds, which may have a greater impact than interest rates. The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index. The Fund may also invest in other ETFs (including other iShares funds), U.S. government securities, options and swap contracts, short-term paper, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates. The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index. 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).
Risk [Heading]	rr_RiskHeading	<b>Summary of Principal Risks </b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below (either directly or through its investments in the Underlying Fund), any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF. Asset Class Risk. Securities and other assets in the Fund's or the Underlying Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes. Assets Under Management (AUM) Risk. From time to time, an Authorized Participant (as defined in the Creations and Redemptions section of this Prospectus, a third-party investor, the Fund’s adviser or an affiliate of the Fund’s adviser, or a fund may invest in the Fund and hold its investment for a specific period of time to allow the Fund to achieve size or scale. There can be no assurance that any such entity would not redeem its investment or that the size of the Fund would be maintained at such levels, which could negatively impact the Fund. Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of the Prospectus), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes. Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund or the Underlying Fund may “call” or repay the security before its stated maturity, and the Fund or the Underlying Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's or Underlying Fund's income, or in securities with greater risks or with other less favorable features. Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's or the Underlying Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s or Underlying Fund's investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation. Custody Risk. Less developed securities markets are more likely to experience problems with the clearing and settling of trades, as well as the holding of securities by local banks, agents and depositories. Cyber Security Risk. Failures or breaches of the electronic systems of the Fund or the Underlying Fund, the Fund's or the Underlying Fund's adviser, distributor, or other service providers (including the benchmark provider), market makers, Authorized Participants, hedging counterparties to the Fund or the issuers of securities in which the Fund or the Underlying Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants, hedging counterparties to the Fund or issuers of securities in which the Fund or the Underlying Fund invests. Derivatives Risk. The Fund’s or Underlying Fund's use of derivatives may reduce the Fund’s or Underlying Fund's returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Counterparty risk for over-the-counter (“OTC”) derivatives is generally higher than that for derivatives traded on an exchange or through a clearing house. A risk of the Fund’s or Underlying Fund's use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund or Underlying Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund or Underlying Fund to sell or otherwise close a derivatives position could expose the Fund or Underlying Fund to losses and could make derivatives more difficult for the Fund or Underlying Fund to value accurately. The Fund or Underlying Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund or Underlying Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund or Underlying Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund or Underlying Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund or Underlying Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives. Extension Risk. During periods of rising interest rates, certain debt obligations may be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in the Fund’s or the Underlying Fund's income and potentially in the value of the Fund’s or an Underlying Fund's investments. Geographic Risk. A natural disaster could occur in a geographic region in which the Fund or the Underlying Fund invests, which could affect the economy or particular business operations of companies in the specific geographic region, causing an adverse impact on the Fund's or the Underlying Fund's investments in the affected region. Hedging Risk. The Fund seeks to mitigate the potential impact of interest rates on the performance of emerging market bonds by entering into positions in U.S. Treasury and other futures and interest rate swaps. The Fund’s Treasury and other futures positions are not intended to mitigate credit risk or other factors influencing the price of emerging market bonds, which may have a greater impact than interest rates. There is no guarantee that the Fund’s Treasury and other futures and interest rate swap positions will completely eliminate the interest rate risk of the long positions in emerging market bonds. In addition, when interest rates fall, long–only emerging market bond investments will perform better than the Fund’s investments. In certain falling interest rate environments, the Fund’s hedging strategy could result in disproportionately larger losses in the Treasury and other futures and interest rate swap positions as compared to gains in the long emerging market bond positions attributable to interest rate changes. There is no guarantee the Fund will have positive returns, even in environments of sharply rising interest rates in which the Fund’s Treasury and other futures and interest rate swap positions might be expected to mitigate the effects of such rises. The Fund will incur expenses when entering into Treasury and other futures and interest rate swap positions. High Yield Securities Risk. Securities that are rated below investment-grade (commonly referred to as “junk bonds,” which may include those bonds rated below “BBB-” by S&P Global Ratings and Fitch Ratings, Inc. (“Fitch”) or “Baa3” by Moody's Investors Service, Inc. (“Moody's”)), or are unrated, may be deemed speculative, may involve greater levels of risk than higher-rated securities of similar maturity and may be more likely to default. Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund or the Underlying Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, bonds in the Underlying Fund's index are substituted, or the Fund or the Underlying Fund otherwise needs to purchase additional bonds. Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund or the Underlying Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. The Fund will take positions in Treasury and other futures and interest rate swaps. As a result, when interest rates decline, the Fund will underperform funds with long-only investments in the same emerging market bonds as the Fund. There is no guarantee that the Fund or Underlying Fund will have positive performance even in environments of sharply rising interest rates. There is no guarantee that the Fund or Underlying Fund will be able to successfully mitigate interest rate risk. Interest Rate Swap Risk. Interest rate swaps are subject to risks applicable to swaps generally, including the risk that a counterparty fails to meet its obligations and the risk that the Fund is not able to liquidate such swap in a timely manner or at all, which could result in losses to the Fund. Because the Fund will invest in swaps that are subject to central clearing, these swaps are subject to the risk that a central clearinghouse will go into bankruptcy or become non-operational, and sometimes involve increased transaction costs. Counterparties to OTC swaps are not subject to these risks. An interest rate swap may fail to perform as intended and may not offset adverse changes in interest rates fully or at all. An interest rate swap may also reduce the Fund’s gains due to favorable changes in interest rates and result in losses to the Fund. Counterparties to interest rate swaps are subject to manipulation in the marketplace of the reference benchmark rate, which may affect the utility of the swap as a hedge. Investment in the Underlying Fund Risk. The Fund expects to invest a substantial portion of its assets in the Underlying Fund, so the Fund’s investment performance is likely to be directly related to the performance of the Underlying Fund. The Fund’s NAV will change with changes in the value of the Underlying Fund and other securities and instruments in which the Fund invests based on their market valuations. An investment in the Fund will entail more costs and expenses than a direct investment in the Underlying Fund. As the Fund’s allocations to the Underlying Fund change from time to time, or to the extent that the expense ratio of the Underlying Fund changes, the weighted average operating expenses borne by the Fund may increase or decrease. Through its investment in the Underlying Fund, the Fund is exposed to Management Risk, Market Risk, and Market Trading Risk, among other risks. Issuer Risk. The performance of the Fund depends on the performance of individual instruments to which the Fund or the Underlying Fund has exposure. Changes in the financial condition or credit rating of an issuer of those securities or counterparty on other instruments may cause the value of the securities or instruments to decline. Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. Market Risk. The Fund and the Underlying Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Market Trading Risk. The Fund and the Underlying Fund face numerous market trading risks, including the potential lack of an active market for their shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's or Underlying Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S AND THE UNDERLYING FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. Non-U.S. Agency Debt Risk. The Fund invests in uncollateralized bonds issued by agencies, subdivisions or instrumentalities of foreign governments. Bonds issued by foreign government agencies, subdivisions or instrumentalities are generally backed only by the general creditworthiness and reputation of the entity issuing the bonds and may not be backed by the full faith and credit of the foreign government. Moreover, a foreign government that explicitly provides its full faith and credit to a particular entity may be, due to changed circumstances, unable or unwilling to provide that support. A non-U.S. agency’s operations and financial condition are influenced by the foreign government’s economic and other policies. Non-U.S. Issuers Risk. Securities issued by non-U.S. issuers carry different risks from securities issued by U.S. issuers. These risks include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or confiscatory taxation, adverse changes in investment or exchange control regulations, political instability, regulatory and economic differences, and potential restrictions on the flow of international capital. The Fund is specifically exposed to Asian Economic Risk, Central and South American Economic Risk, Eastern European Economic Risk and Middle Eastern Economic Risk. Operational Risk. The Fund or the Underlying Fund are exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s or the Underlying Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund, the Underlying Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks. Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund or the Underlying Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential. Privately-Issued Securities Risk. The Fund or the Underlying Fund will 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”). Privately-issued securities are securities that have not been registered under the 1933 Act and as a result may be subject to legal restrictions on resale. Privately-issued securities are generally not traded on established markets. As a result of the absence of a public trading market, privately issued securities may be deemed to be illiquid investments, may be more difficult to value than publicly traded securities and may be subject to wide fluctuations in value. Delay or difficulty in selling such securities may result in a loss to the Fund. Privatization Risk. Some countries in which the Fund or an Underlying Fund invests have privatized, or have begun the process of privatizing, certain entities and industries. Privatized entities may lose money or be re-nationalized. Reliance on Trading Partners Risk. The Fund or the Underlying Fund invests in countries or regions whose economies are heavily dependent upon trading with key partners. Any reduction in this trading may have an adverse impact on the Fund's investments. Through its holdings of securities of certain issuers, the Fund is specifically exposed to Asian Economic Risk, Central and South American Economic Risk, European Economic Risk and U.S. Economic Risk. Risk of Investing in Emerging Markets. Investments in emerging market issuers may be subject to a greater risk of loss than investments in issuers located or operating in more developed markets. Emerging markets may be more likely to experience inflation, political turmoil and rapid changes in economic conditions than more developed markets. Emerging markets often have less uniformity in accounting and reporting requirements, less reliable securities valuations and greater risk associated with custody of securities than developed markets. Risk of Investing in Russia. Investing in Russian securities involves significant risks, including legal, regulatory and economic risks that are specific to Russia. In addition, investing in Russian securities involves risks associated with the settlement of portfolio transactions and loss of the Fund’s ownership rights in its portfolio securities as a result of the system of share registration and custody in Russia. A number of jurisdictions, including the U.S., Canada and the European Union (the “EU”), have imposed economic sanctions on certain Russian individuals and Russian corporate entities. These and future sanctions, or even the threat of further sanctions, may adversely affect Russia’s economy and the Fund’s or the Underlying Fund's investments. Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses. Securities Lending Risk. The Fund or the Underlying Fund may engage in securities lending. Securities lending involves the risk that the Fund or the Underlying Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund or the Underlying Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund or Underlying Fund. Small Fund Risk. When the Fund’s size is small, the Fund may experience low trading volume and wide bid/ask spreads. In addition, the Fund may face the risk of being delisted if the Fund does not meet certain conditions of the listing exchange. Sovereign and Quasi-Sovereign Obligations Risk. The Fund or the Underlying Fund may invest in securities issued by or guaranteed by sovereign governments and by entities affiliated with or backed by non-U.S. sovereign governments, which may be unable or unwilling to repay principal or interest when due. In times of economic uncertainty, the prices of these securities may be more volatile than those of corporate debt obligations or of other government debt obligations. Structural Risk. The countries in which the Fund or the Underlying Fund invests may be subject to considerable degrees of economic, political and social instability. Tax Risk. Because the Fund invests in the Underlying Fund, the Fund’s realized losses on sales of shares of the Underlying Fund may be indefinitely or permanently deferred as “wash sales.” Distributions of short-term capital gains by the Underlying Fund will be recognized as ordinary income by the Fund and would not be offset by the Fund’s capital loss carryforwards, if any. Capital loss carryforwards of the Underlying Fund, if any, would not offset net capital gains of the Fund. Each of these effects is caused by the Fund’s investment in the Underlying Fund and may result in distributions to Fund shareholders being of higher magnitude and less likely to qualify for lower capital gain tax rates than if the Fund were to invest directly in the securities and other instruments comprising its portfolio.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>Performance Information </b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-800-iShares (1-800-474-2737) (toll free)
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.iShares.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>Year by Year Returns (Years Ended December 31)</b>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The best calendar quarter return during the periods shown above was 3.83% in the 1st quarter of 2017; the worst was -3.84% in the 4th quarter of 2018. Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).
Performance Table Heading	rr_PerformanceTableHeading	<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”).
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.
iShares Interest Rate Hedged Emerging Markets Bond ETF | iShares Interest Rate Hedged Emerging Markets Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.75%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	none
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.38%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.13%
Fee Waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.65%)
Total Annual Fund Operating Expenses After Fee Waiver	rr_NetExpensesOverAssets	0.48%
1 Year	rr_ExpenseExampleYear01	$ 49
3 Years	rr_ExpenseExampleYear03	154
5 Years	rr_ExpenseExampleYear05	422
10 Years	rr_ExpenseExampleYear10	$ 1,189
2016	rr_AnnualReturn2016	9.37%
2017	rr_AnnualReturn2017	9.37%
2018	rr_AnnualReturn2018	(3.77%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	best
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Mar. 31, 2017
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	3.83%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	worst
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2018
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(3.84%)
One Year	rr_AverageAnnualReturnYear01	(3.77%)
Since Fund Inception	rr_AverageAnnualReturnSinceInception	3.29%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jul. 22, 2015
iShares Interest Rate Hedged Emerging Markets Bond ETF | Return After Taxes on Distributions | iShares Interest Rate Hedged Emerging Markets Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(5.68%)	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	1.50%	[1]
iShares Interest Rate Hedged Emerging Markets Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares | iShares Interest Rate Hedged Emerging Markets Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(2.21%)	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	1.72%	[1]
iShares Interest Rate Hedged Emerging Markets Bond ETF | J.P. Morgan EMBI Global Core Swap Hedged Index (Index returns do not reflect deductions for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(3.61%)
Since Fund Inception	rr_AverageAnnualReturnSinceInception	3.57%

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

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iShares Interest Rate Hedged High Yield Bond ETF

iSHARES^® INTEREST RATE HEDGED HIGH YIELD BOND ETF<br/>Ticker: HYGH                                 Stock Exchange: NYSE Arca

<b>Investment Objective</b>

The iShares Interest Rate Hedged High Yield Bond ETF (the “Fund”) seeks to mitigate the interest rate risk of a portfolio composed of U.S. dollar-denominated, high yield corporate bonds.

<b>Fees and Expenses</b>

The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”). BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees so that the Fund’s total annual fund operating expenses after fee waiver is equal to the Acquired Fund Fees and Expenses attributable to the Fund’s investment in the iShares iBoxx $ High Yield Corporate Bond ETF (“HYG” or the “Underlying Fund”), after taking into account any fee waivers by HYG, plus 0.05% through February 28, 2022. The contractual waiver may be terminated prior to February 28, 2022 only upon written agreement of the Trust and BFA.

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

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

Annual Fund Operating Expenses	Management Fees	Distribution and Service (12b-1) Fees	Other Expenses	Acquired Fund Fees and Expenses	Total Annual Fund Operating Expenses	Fee Waiver	Total Annual Fund Operating Expenses After Fee Waiver
iShares Interest Rate Hedged High Yield Bond ETF | iShares Interest Rate Hedged High Yield Bond ETF	0.65%	none	none	0.48%	1.13%	(0.60%)	0.53%

<b>Example. </b>

This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example	1 Year	3 Years	5 Years	10 Years
iShares Interest Rate Hedged High Yield Bond ETF | iShares Interest Rate Hedged High Yield Bond ETF | USD ($)	54	170	438	1,203

<b>Portfolio Turnover.</b>

The Fund and the Underlying Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate for the Fund or the Underlying Fund may indicate higher transaction costs and may cause the Fund or the Underlying Fund to incur increased expenses. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example (except costs to the Underlying Fund included as part of Acquired Fund Fees and Expenses), affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 0% of the average value of its portfolio. To the extent the Underlying Fund incurs costs from high portfolio turnover, such costs may have a negative effect on the performance of the Fund.

<b>Principal Investment Strategies</b>

The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in U.S. dollar-denominated high yield bonds, in one or more underlying funds that principally invest in high yield bonds. The Fund intends to invest a substantial portion of its assets in the Underlying Fund. The Fund attempts to mitigate the interest rate risk of the underlying securities or the Underlying Fund (as determined by BFA) primarily through the use of positions in both U.S. Treasury futures contracts and interest rate swaps (i.e., enter into a contract or contracts in which the Fund will make fixed-rate payments while receiving floating-rate payments based on a reference rate). The Fund may also invest in other interest rate futures contracts, including but not limited to, Eurodollar and Federal Funds futures. The Fund’s futures and interest rate swap positions are not intended to mitigate credit risk or other factors influencing the price of high yield corporate bonds, which may have a greater impact than interest rates.

The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index.

The Fund may also invest in other ETFs (including other iShares funds), U.S. government securities, options and swap contracts, short-term paper, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates.

The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index.

The Fund may lend securities representing up to one-third of the value of the Fund's total assets (including the value of the collateral received).

<b>Summary of Principal Risks</b>

As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below (either directly or through its investments in the Underlying Fund), any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF.

Asset Class Risk. Securities and other assets in the Fund's or the Underlying Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes.

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of this prospectus (“the Prospectus”)), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes.

Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund or the Underlying Fund may “call” or repay the security before its stated maturity, and the Fund or the Underlying Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's or Underlying Fund's income, or in securities with greater risks or with other less favorable features.

Communication Services Sector Risk. Companies in the communications sector may be affected by industry competition, substantial capital requirements, government regulation, cyclicality of revenues and earnings, obsolescence of communications products and services due to technological advancement, a potential decrease in the discretionary income of targeted individuals and changing consumer tastes and interests.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's or the Underlying Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class.

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

Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s or Underlying Fund's investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation.

Cyber Security Risk. Failures or breaches of the electronic systems of the Fund or the Underlying Fund, the Fund's or the Underlying Fund's adviser, distributor, or other service providers (including the benchmark provider), market makers, Authorized Participants, hedging counterparties to the Fund or the issuers of securities in which the Fund or the Underlying Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants, hedging counterparties to the Fund or issuers of securities in which the Fund or the Underlying Fund invests.

Derivatives Risk. The Fund’s or Underlying Fund's use of derivatives may reduce the Fund’s or Underlying Fund's returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Counterparty risk for over-the-counter (“OTC”) derivatives is generally higher than that for derivatives traded on an exchange or through a clearing house. A risk of the Fund’s or Underlying Fund's use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund or Underlying Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund or Underlying Fund to sell or otherwise close a derivatives position could expose the Fund or Underlying Fund to losses and could make derivatives more difficult for the Fund or Underlying Fund to value accurately. The Fund or Underlying Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund or Underlying Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund or Underlying Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund or Underlying Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund or Underlying Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives.

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

Geographic Risk. A natural disaster could occur in a geographic region in which the Fund or the Underlying Fund invests, which could affect the economy or particular business operations of companies in the specific geographic region, causing an adverse impact on the Fund's or the Underlying Fund's investments in the affected region.

Hedging Risk. The Fund seeks to mitigate the potential impact of interest rates on the performance of high yield bonds by entering into positions in U.S. Treasury and other futures and interest rate swaps. The Fund’s Treasury and other futures positions are not intended to mitigate credit risk or other factors influencing the price of high yield bonds, which may have a greater impact than interest rates. There is no guarantee that the Fund’s Treasury and other futures and interest rate swap positions will completely eliminate the interest rate risk of the long positions in high yield bonds. In addition, when interest rates fall, long–only high yield bond investments will perform better than the Fund’s investments. In certain falling interest rate environments, the Fund’s hedging strategy could result in disproportionately larger losses in the Treasury and other futures and interest rate swap positions as compared to gains in the long high yield bond positions attributable to interest rate changes. There is no guarantee the Fund will have positive returns, even in environments of sharply rising interest rates in which the Fund’s Treasury and other futures and interest rate swap positions might be expected to mitigate the effects of such rises. The Fund will incur expenses when entering into Treasury and other futures and interest rate swap positions.

High Yield Securities Risk. Securities that are rated below investment-grade (commonly referred to as “junk bonds,” which may include those bonds rated below “BBB-” by S&P Global Ratings and Fitch Ratings, Inc. (“Fitch”) or “Baa3” by Moody's Investors Service, Inc. (“Moody's”)), or are unrated, may be deemed speculative, may involve greater levels of risk than higher-rated securities of similar maturity and may be more likely to default.

Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices.

Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund or the Underlying Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, bonds in the Underlying Fund's index are substituted, or the Fund or the Underlying Fund otherwise needs to purchase additional bonds.

Industrials Sector Risk. Companies in the industrials sector may be adversely affected by changes in the supply of and demand for products and services, product obsolescence, claims for environmental damage or product liability and changes in general economic conditions, among other factors.

Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund or the Underlying Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. The Fund will take positions in Treasury and other futures and interest rate swaps. As a result, when interest rates decline, the Fund will underperform funds with long-only investments in the same high yield bonds as the Fund. There is no guarantee that the Fund or Underlying Fund will have positive performance even in environments of sharply rising interest rates. There is no guarantee that the Fund or Underlying Fund will be able to successfully mitigate interest rate risk.

Interest Rate Swap Risk. Interest rate swaps are subject to risks applicable to swaps generally, including the risk that a counterparty fails to meet its obligations and the risk that the Fund is not able to liquidate such swap in a timely manner or at all, which could result in losses to the Fund. Because the Fund will invest in swaps that are subject to central clearing, these swaps are subject to the risk that a central clearinghouse will go into bankruptcy or become non-operational, and sometimes involve increased transaction costs. Counterparties to OTC swaps are not subject to these risks. An interest rate swap may fail to perform as intended and may not offset adverse changes in interest rates fully or at all. An interest rate swap may also reduce the Fund’s gains due to favorable changes in interest rates and result in losses to the Fund. Counterparties to interest rate swaps are subject to manipulation in the marketplace of the reference benchmark rate, which may affect the utility of the swap as a hedge.

Investment in the Underlying Fund Risk. The Fund expects to invest a substantial portion of its assets in the Underlying Fund, so the Fund’s investment performance is likely to be directly related to the performance of the Underlying Fund. The Fund’s NAV will change with changes in the value of the Underlying Fund and other securities and instruments in which the Fund invests based on their market valuations. An investment in the Fund will entail more costs and expenses than a direct investment in the Underlying Fund.

As the Fund’s allocations to the Underlying Fund change from time to time, or to the extent that the expense ratio of the Underlying Fund changes, the weighted average operating expenses borne by the Fund may increase or decrease.

Through its investment in the Underlying Fund, the Fund is exposed to Management Risk, Market Risk, and Market Trading Risk, among other risks.

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

Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective.

Market Risk. The Fund and the Underlying Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns.

Market Trading Risk. The Fund and the Underlying Fund face numerous market trading risks, including the potential lack of an active market for their shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's or Underlying Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S AND THE UNDERLYING FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

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

Operational Risk. The Fund and the Underlying Fund are exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s or the Underlying Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund, the Underlying Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund or the Underlying Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential.

Privately-Issued Securities Risk. The Fund or the Underlying Fund will 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 (“1933 Act”). Privately-issued securities are securities that have not been registered under the 1933 Act and as a result may be subject to legal restrictions on resale. Privately-issued securities are generally not traded on established markets. As a result of the absence of a public trading market, privately issued securities may be deemed to be illiquid investments, may be more difficult to value than publicly traded securities and may be subject to wide fluctuations in value. Delay or difficulty in selling such securities may result in a loss to the Fund.

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

Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses.

Securities Lending Risk. The Fund or the Underlying Fund may engage in securities lending. Securities lending involves the risk that the Fund or the Underlying Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund or the Underlying Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund or Underlying Fund.

Tax Risk. The Underlying Fund invests in derivatives. The federal income tax treatment of a derivative may not be as favorable as a direct investment in an underlying asset. Derivatives may produce taxable income and taxable realized gain. Derivatives may adversely affect the timing, character and amount of income the Underlying Fund realizes from its investments. As a result, a larger portion of the Fund’s distributions may be treated as ordinary income rather than as capital gains. In addition, certain derivatives are subject to mark-to-market or straddle provisions of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). If such provisions are applicable, there could be an increase (or decrease) in the amount of taxable dividends paid by the Fund. Income from swaps is generally taxable. In addition, the tax treatment of certain derivatives, such as swaps, is unsettled and may be subject to future legislation, regulation or administrative pronouncements issued by the U.S. Internal Revenue Service (“IRS”).

<b>Performance Information</b>

The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.

<b>Year by Year Returns (Years Ended December 31)</b>

The best calendar quarter return during the periods shown above was 4.98% in the 3rd quarter of 2016; the worst was -6.25% in the 3rd quarter of 2015.

Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).

<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>

Average Annual Total Returns - iShares Interest Rate Hedged High Yield Bond ETF		One Year	Since Fund Inception	Inception Date
iShares Interest Rate Hedged High Yield Bond ETF		(0.87%)	1.73%	May 27, 2014
iShares Interest Rate Hedged High Yield Bond ETF | Return After Taxes on Distributions	[1]	(3.29%)	(0.55%)
iShares Interest Rate Hedged High Yield Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares	[1]	(0.47%)	0.29%
Markit iBoxx USD Liquid High Yield Interest Rate Hedged Swaps Index (Index returns do not reflect deductions for fees, expenses, or taxes)	[2]	(1.02%)	2.25%

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[2] The Markit iBoxx USD Liquid High Yield Interest Rate Hedged Swaps Index is an unmanaged index that reflects the duration hedged performance of U.S. dollar-denominated high yield corporate debt.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	iShares U.S. ETF Trust
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
iShares Interest Rate Hedged High Yield Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	iSHARES<sup>®</sup> INTEREST RATE HEDGED HIGH YIELD BOND ETF<br/>Ticker: HYGH                                 Stock Exchange: NYSE Arca
Objective [Heading]	rr_ObjectiveHeading	<b>Investment Objective</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The iShares Interest Rate Hedged High Yield Bond ETF (the “Fund”) seeks to mitigate the interest rate risk of a portfolio composed of U.S. dollar-denominated, high yield corporate bonds.
Expense [Heading]	rr_ExpenseHeading	<b>Fees and Expenses</b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”). BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees so that the Fund’s total annual fund operating expenses after fee waiver is equal to the Acquired Fund Fees and Expenses attributable to the Fund’s investment in the iShares iBoxx $ High Yield Corporate Bond ETF (“HYG” or the “Underlying Fund”), after taking into account any fee waivers by HYG, plus 0.05% through February 28, 2022. The contractual waiver may be terminated prior to February 28, 2022 only upon written agreement of the Trust and BFA. You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>Annual Fund Operating Expenses<br/>(ongoing expenses that you pay each year as a<br/>percentage of the value of your investments) </b>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	February 28, 2022
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>Portfolio Turnover.</b>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund and the Underlying Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate for the Fund or the Underlying Fund may indicate higher transaction costs and may cause the Fund or the Underlying Fund to incur increased expenses. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example (except costs to the Underlying Fund included as part of Acquired Fund Fees and Expenses), affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 0% of the average value of its portfolio. To the extent the Underlying Fund incurs costs from high portfolio turnover, such costs may have a negative effect on the performance of the Fund.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	none
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”).
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>Example. </b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>Principal Investment Strategies</b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in U.S. dollar-denominated high yield bonds, in one or more underlying funds that principally invest in high yield bonds. The Fund intends to invest a substantial portion of its assets in the Underlying Fund. The Fund attempts to mitigate the interest rate risk of the underlying securities or the Underlying Fund (as determined by BFA) primarily through the use of positions in both U.S. Treasury futures contracts and interest rate swaps (i.e., enter into a contract or contracts in which the Fund will make fixed-rate payments while receiving floating-rate payments based on a reference rate). The Fund may also invest in other interest rate futures contracts, including but not limited to, Eurodollar and Federal Funds futures. The Fund’s futures and interest rate swap positions are not intended to mitigate credit risk or other factors influencing the price of high yield corporate bonds, which may have a greater impact than interest rates. The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index. The Fund may also invest in other ETFs (including other iShares funds), U.S. government securities, options and swap contracts, short-term paper, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates. The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index. The Fund may lend securities representing up to one-third of the value of the Fund's total assets (including the value of the collateral received).
Risk [Heading]	rr_RiskHeading	<b>Summary of Principal Risks</b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below (either directly or through its investments in the Underlying Fund), any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF. Asset Class Risk. Securities and other assets in the Fund's or the Underlying Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes. Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of this prospectus (“the Prospectus”)), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes. Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund or the Underlying Fund may “call” or repay the security before its stated maturity, and the Fund or the Underlying Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's or Underlying Fund's income, or in securities with greater risks or with other less favorable features. Communication Services Sector Risk. Companies in the communications sector may be affected by industry competition, substantial capital requirements, government regulation, cyclicality of revenues and earnings, obsolescence of communications products and services due to technological advancement, a potential decrease in the discretionary income of targeted individuals and changing consumer tastes and interests. Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's or the Underlying Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. Consumer Staples Sector Risk. The consumer staples sector may be affected by, among other things, marketing campaigns, changes in consumer demands, government regulations and changes in commodity prices. Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s or Underlying Fund's investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation. Cyber Security Risk. Failures or breaches of the electronic systems of the Fund or the Underlying Fund, the Fund's or the Underlying Fund's adviser, distributor, or other service providers (including the benchmark provider), market makers, Authorized Participants, hedging counterparties to the Fund or the issuers of securities in which the Fund or the Underlying Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants, hedging counterparties to the Fund or issuers of securities in which the Fund or the Underlying Fund invests. Derivatives Risk. The Fund’s or Underlying Fund's use of derivatives may reduce the Fund’s or Underlying Fund's returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Counterparty risk for over-the-counter (“OTC”) derivatives is generally higher than that for derivatives traded on an exchange or through a clearing house. A risk of the Fund’s or Underlying Fund's use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund or Underlying Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund or Underlying Fund to sell or otherwise close a derivatives position could expose the Fund or Underlying Fund to losses and could make derivatives more difficult for the Fund or Underlying Fund to value accurately. The Fund or Underlying Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund or Underlying Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund or Underlying Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund or Underlying Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund or Underlying Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives. Extension Risk. During periods of rising interest rates, certain debt obligations may be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in the Fund’s or the Underlying Fund's income and potentially in the value of the Fund’s or the Underlying Fund's investments. Geographic Risk. A natural disaster could occur in a geographic region in which the Fund or the Underlying Fund invests, which could affect the economy or particular business operations of companies in the specific geographic region, causing an adverse impact on the Fund's or the Underlying Fund's investments in the affected region. Hedging Risk. The Fund seeks to mitigate the potential impact of interest rates on the performance of high yield bonds by entering into positions in U.S. Treasury and other futures and interest rate swaps. The Fund’s Treasury and other futures positions are not intended to mitigate credit risk or other factors influencing the price of high yield bonds, which may have a greater impact than interest rates. There is no guarantee that the Fund’s Treasury and other futures and interest rate swap positions will completely eliminate the interest rate risk of the long positions in high yield bonds. In addition, when interest rates fall, long–only high yield bond investments will perform better than the Fund’s investments. In certain falling interest rate environments, the Fund’s hedging strategy could result in disproportionately larger losses in the Treasury and other futures and interest rate swap positions as compared to gains in the long high yield bond positions attributable to interest rate changes. There is no guarantee the Fund will have positive returns, even in environments of sharply rising interest rates in which the Fund’s Treasury and other futures and interest rate swap positions might be expected to mitigate the effects of such rises. The Fund will incur expenses when entering into Treasury and other futures and interest rate swap positions. High Yield Securities Risk. Securities that are rated below investment-grade (commonly referred to as “junk bonds,” which may include those bonds rated below “BBB-” by S&P Global Ratings and Fitch Ratings, Inc. (“Fitch”) or “Baa3” by Moody's Investors Service, Inc. (“Moody's”)), or are unrated, may be deemed speculative, may involve greater levels of risk than higher-rated securities of similar maturity and may be more likely to default. Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund or the Underlying Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, bonds in the Underlying Fund's index are substituted, or the Fund or the Underlying Fund otherwise needs to purchase additional bonds. Industrials Sector Risk. Companies in the industrials sector may be adversely affected by changes in the supply of and demand for products and services, product obsolescence, claims for environmental damage or product liability and changes in general economic conditions, among other factors. Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund or the Underlying Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. The Fund will take positions in Treasury and other futures and interest rate swaps. As a result, when interest rates decline, the Fund will underperform funds with long-only investments in the same high yield bonds as the Fund. There is no guarantee that the Fund or Underlying Fund will have positive performance even in environments of sharply rising interest rates. There is no guarantee that the Fund or Underlying Fund will be able to successfully mitigate interest rate risk. Interest Rate Swap Risk. Interest rate swaps are subject to risks applicable to swaps generally, including the risk that a counterparty fails to meet its obligations and the risk that the Fund is not able to liquidate such swap in a timely manner or at all, which could result in losses to the Fund. Because the Fund will invest in swaps that are subject to central clearing, these swaps are subject to the risk that a central clearinghouse will go into bankruptcy or become non-operational, and sometimes involve increased transaction costs. Counterparties to OTC swaps are not subject to these risks. An interest rate swap may fail to perform as intended and may not offset adverse changes in interest rates fully or at all. An interest rate swap may also reduce the Fund’s gains due to favorable changes in interest rates and result in losses to the Fund. Counterparties to interest rate swaps are subject to manipulation in the marketplace of the reference benchmark rate, which may affect the utility of the swap as a hedge. Investment in the Underlying Fund Risk. The Fund expects to invest a substantial portion of its assets in the Underlying Fund, so the Fund’s investment performance is likely to be directly related to the performance of the Underlying Fund. The Fund’s NAV will change with changes in the value of the Underlying Fund and other securities and instruments in which the Fund invests based on their market valuations. An investment in the Fund will entail more costs and expenses than a direct investment in the Underlying Fund. As the Fund’s allocations to the Underlying Fund change from time to time, or to the extent that the expense ratio of the Underlying Fund changes, the weighted average operating expenses borne by the Fund may increase or decrease. Through its investment in the Underlying Fund, the Fund is exposed to Management Risk, Market Risk, and Market Trading Risk, among other risks. Issuer Risk. The performance of the Fund depends on the performance of individual instruments to which the Fund or the Underlying Fund has exposure. Changes in the financial condition or credit rating of an issuer of those securities or counterparty on other instruments may cause the value of the securities or instruments to decline. Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. Market Risk. The Fund and the Underlying Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Market Trading Risk. The Fund and the Underlying Fund face numerous market trading risks, including the potential lack of an active market for their shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's or Underlying Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S AND THE UNDERLYING FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. Non-U.S. Issuers Risk. Securities issued by non-U.S. issuers carry different risks from securities issued by U.S. issuers. These risks include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or confiscatory taxation, adverse changes in investment or exchange control regulations, political instability, regulatory and economic differences, and potential restrictions on the flow of international capital. Operational Risk. The Fund and the Underlying Fund are exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s or the Underlying Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund, the Underlying Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks. Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund or the Underlying Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential. Privately-Issued Securities Risk. The Fund or the Underlying Fund will 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 (“1933 Act”). Privately-issued securities are securities that have not been registered under the 1933 Act and as a result may be subject to legal restrictions on resale. Privately-issued securities are generally not traded on established markets. As a result of the absence of a public trading market, privately issued securities may be deemed to be illiquid investments, may be more difficult to value than publicly traded securities and may be subject to wide fluctuations in value. Delay or difficulty in selling such securities may result in a loss to the Fund. Risk of Investing in the U.S. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund or the Underlying Fund has exposure. Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses. Securities Lending Risk. The Fund or the Underlying Fund may engage in securities lending. Securities lending involves the risk that the Fund or the Underlying Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund or the Underlying Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund or Underlying Fund. Tax Risk. The Underlying Fund invests in derivatives. The federal income tax treatment of a derivative may not be as favorable as a direct investment in an underlying asset. Derivatives may produce taxable income and taxable realized gain. Derivatives may adversely affect the timing, character and amount of income the Underlying Fund realizes from its investments. As a result, a larger portion of the Fund’s distributions may be treated as ordinary income rather than as capital gains. In addition, certain derivatives are subject to mark-to-market or straddle provisions of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). If such provisions are applicable, there could be an increase (or decrease) in the amount of taxable dividends paid by the Fund. Income from swaps is generally taxable. In addition, the tax treatment of certain derivatives, such as swaps, is unsettled and may be subject to future legislation, regulation or administrative pronouncements issued by the U.S. Internal Revenue Service (“IRS”).
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>Performance Information</b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-800-iShares (1-800-474-2737) (toll free)
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.iShares.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>Year by Year Returns (Years Ended December 31)</b>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The best calendar quarter return during the periods shown above was 4.98% in the 3rd quarter of 2016; the worst was -6.25% in the 3rd quarter of 2015. Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).
Performance Table Heading	rr_PerformanceTableHeading	<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”).
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.
iShares Interest Rate Hedged High Yield Bond ETF | iShares Interest Rate Hedged High Yield Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.65%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	none
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.48%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.13%
Fee Waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.60%)
Total Annual Fund Operating Expenses After Fee Waiver	rr_NetExpensesOverAssets	0.53%
1 Year	rr_ExpenseExampleYear01	$ 54
3 Years	rr_ExpenseExampleYear03	170
5 Years	rr_ExpenseExampleYear05	438
10 Years	rr_ExpenseExampleYear10	$ 1,203
2015	rr_AnnualReturn2015	(6.33%)
2016	rr_AnnualReturn2016	12.93%
2017	rr_AnnualReturn2017	6.53%
2018	rr_AnnualReturn2018	(0.87%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	best
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2016
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	4.98%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	worst
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(6.25%)
One Year	rr_AverageAnnualReturnYear01	(0.87%)
Since Fund Inception	rr_AverageAnnualReturnSinceInception	1.73%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 27, 2014
iShares Interest Rate Hedged High Yield Bond ETF | Return After Taxes on Distributions | iShares Interest Rate Hedged High Yield Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(3.29%)	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	(0.55%)	[1]
iShares Interest Rate Hedged High Yield Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares | iShares Interest Rate Hedged High Yield Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(0.47%)	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	0.29%	[1]
iShares Interest Rate Hedged High Yield Bond ETF | Markit iBoxx USD Liquid High Yield Interest Rate Hedged Swaps Index (Index returns do not reflect deductions for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(1.02%)	[2]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	2.25%	[2]

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[2] The Markit iBoxx USD Liquid High Yield Interest Rate Hedged Swaps Index is an unmanaged index that reflects the duration hedged performance of U.S. dollar-denominated high yield corporate debt.

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iShares Short Maturity Bond ETF

iSHARES^® SHORT MATURITY<br/>BOND ETF<br />Ticker: NEAR                                 Stock Exchange: Cboe BZX

<b>Investment Objective</b>

The iShares Short Maturity Bond ETF (the “Fund”) seeks to maximize current income.

<b>Fees and Expenses</b>

The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses.

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

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

Annual Fund Operating Expenses	Management Fees	Distribution and Service (12b-1) Fees	Other Expenses	Total Annual Fund Operating Expenses
iShares Short Maturity Bond ETF | iShares Short Maturity Bond ETF	0.25%	none	none	0.25%

<b>Example.</b>

This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example	1 Year	3 Years	5 Years	10 Years
iShares Short Maturity Bond ETF | iShares Short Maturity Bond ETF | USD ($)	26	80	141	318

<b>Portfolio Turnover.</b>

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 48% of the average value of its portfolio.

<b>Principal Investment Strategies</b>

The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in a portfolio of U.S. dollar-denominated investment-grade fixed-income securities. The Fund primarily invests in investment-grade fixed-income securities that are rated BBB- or higher by S&P Global Ratings and/or Fitch Ratings, Inc. (“Fitch”), or Baa3 or higher by Moody’s Investors Service, Inc. (“Moody's”), or, if unrated, determined by the Fund's management team to be of equivalent quality. The Fund primarily invests in fixed- and floating-rate securities of varying maturities, such as corporate and government bonds, agency securities, instruments of non-U.S. issuers, privately-issued securities, asset-backed securities (“ABS”) and mortgage-backed securities (“MBS”), structured securities, municipal bonds, repurchase agreements, money market instruments and investment companies. The Fund invests in securities issued by financial institutions such as banks, broker-dealers and insurance companies. The Fund may enter into to-be-announced transactions (“TBA transactions”) on a regular basis with respect to the percentage of the portfolio (if any) that consists of mortgage-backed pass-through securities. BFA or its affiliates may advise the money market funds and investment companies in which the Fund may invest.

Under normal circumstances, the effective duration of the Fund’s portfolio is expected to be one year or less, as calculated by the Fund's management team. Effective duration is a measure of the Fund’s price sensitivity to changes in yields or interest rates; however, investors should be aware that effective duration is not an exact measurement and may not reliably predict a particular security’s price sensitivity to changes in yield or interest rates.

Under normal circumstances, the Fund will also 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. For the purposes of determining the Fund’s weighted average maturity, a security’s final maturity date, or for amortizing securities such as asset-backed and mortgage-backed securities, its weighted average life, will be used for calculation purposes.

The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index. The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index.

The Fund is not a money market fund and does not seek to maintain a stable net asset value of $1.00 per share. Please see the Fund’s Statement of Additional Information (“SAI”) for further information.

The Fund may lend securities representing up to one-third of the value of the Fund's total assets (including the value of the collateral received).

<b>Summary of Principal Risks</b>

As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF.

Asset-Backed and Mortgage-Backed Securities Risk. ABS and MBS (residential and commercial) represent interests in “pools” of mortgages or other assets, including consumer loans or receivables held in trust. ABS and MBS are subject to credit, interest rate, call, extension, valuation and liquidity risk. These securities, in most cases, are not backed by the full faith and credit of the U.S. government and are subject to the risk of default on the underlying asset or mortgage, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain ABS and MBS.

Asset Class Risk. Securities and other assets in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes.

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of this prospectus (“the Prospectus”)), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting.

Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund may “call” or repay the security before its stated maturity, and the Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's income, or in securities with greater risks or with other less favorable features.

Cash Transactions Risk. The Fund expects to effect all of its creations and redemptions for cash, rather than in-kind securities. As a result, the Fund may have to sell portfolio securities at inopportune times in order to obtain the cash needed to meet redemption orders. This may cause the Fund to sell a security and recognize a capital gain or loss that might not have been incurred if it had made a redemption in-kind. The use of cash creations and redemptions may also cause the Fund’s shares to trade in the market at wider bid-ask spreads or greater premiums or discounts to the Fund’s NAV.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class.

Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation.

Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers (including the benchmark provider), market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests.

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

Floating Rate Notes Risk. Securities with floating or variable interest rates can be less sensitive to interest rate changes than securities with fixed interest rates, but may decline in value if their coupon rates do not reset as high, or as quickly, as comparable market interest rates, and generally carry lower yields than fixed notes of the same maturity. Although floating rate notes are less sensitive to interest rate risk than fixed-rate securities, they are subject to credit risk and default risk, which could impair their value.

Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices.

Income Risk. The Fund’s income may decline when interest rates fall because the Fund may hold a significant portion of short duration securities and/or securities that have floating or variable interest rates. The Fund’s income may decline because the Fund invests in lower yielding bonds, and as the bonds in its portfolio mature, are near maturity or are called, the Fund needs to purchase additional bonds.

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

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

Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective.

Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns.

Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

Municipal Securities Risk. Municipal securities can be significantly affected by political or economic changes, including changes made in the law after issuance of the securities, as well as uncertainties in the municipal market related to taxation, legislative changes or the rights of municipal security holders, including in connection with an issuer insolvency. Municipal securities backed by current or anticipated revenues from a specific project or specific assets can be negatively affected by the inability to collect revenues from the project or the assets.

Not a Money Market Fund. The Fund is not a money market fund and is not subject to the strict rules that govern the quality, maturity, liquidity and other features of securities that money market funds may purchase. Under normal circumstances, the Fund’s investments may be more susceptible than a money market fund is to credit risk, interest rate risk, valuation risk and other risks relevant to the Fund’s investments. The Fund does not seek to maintain a stable net asset value of $1.00 per share.

Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential.

Privately-Issued Securities Risk. 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”). Privately-issued securities are securities that have not been registered under the 1933 Act and as a result may be subject to legal restrictions on resale. Privately-issued securities are generally not traded on established markets. As a result of the absence of a public trading market, privately issued securities may be deemed to be illiquid investments, may be more difficult to value than publicly traded securities and may be subject to wide fluctuations in value. Delay or difficulty in selling such securities may result in a loss to the Fund.

Repurchase Agreement Risk. A repurchase agreement is an instrument under which the purchaser (i.e., the Fund) acquires a security and the seller agrees, at the time of the sale, to repurchase the security at a mutually agreed upon time and price. Repurchase agreements may be construed to be collateralized loans by the purchaser to the seller secured by the securities transferred to the purchaser. If a repurchase agreement is construed to be a collateralized loan, the underlying securities will not be considered to be owned by the Fund but only to constitute collateral for the seller’s obligation to pay the repurchase price. If the seller defaults on its obligation under the agreement, the Fund may suffer delays and incur costs or lose money in exercising its rights under the agreement. If the seller fails to repurchase the security and the market value of the security declines, the Fund may lose money.

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

Securities Lending Risk. The Fund may engage in securities lending. Securities lending involves the risk that the Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund.

Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund's valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.

<b>Performance Information</b>

The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus.

<b>Year by Year Returns (Years Ended December 31)</b>

The best calendar quarter return during the periods shown above was 0.63% in the 3rd quarter of 2018; the worst was 0.04% in the 4th quarter of 2014.

Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).

<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>

Average Annual Total Returns - iShares Short Maturity Bond ETF		One Year	Five Years	Since Fund Inception	Inception Date
iShares Short Maturity Bond ETF		1.71%	1.22%	1.22%	Sep. 25, 2013
iShares Short Maturity Bond ETF | Return After Taxes on Distributions	[1]	0.79%	0.66%	0.68%
iShares Short Maturity Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares	[1]	1.01%	0.69%	0.69%
Bloomberg Barclays Short-Term Government/Corporate Index (Index returns do not reflect deductions for fees, expenses or taxes)	[2]	1.99%	0.84%	0.81%

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[2] The Bloomberg Barclays Short-Term Government/Corporate Index is an unmanaged index that measures the performance of government and corporate securities with less than one year remaining to maturity.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	iShares U.S. ETF Trust
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
iShares Short Maturity Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	iSHARES<sup>®</sup> SHORT MATURITY<br/>BOND ETF<br />Ticker: NEAR                                 Stock Exchange: Cboe BZX
Objective [Heading]	rr_ObjectiveHeading	<b>Investment Objective</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The iShares Short Maturity Bond ETF (the “Fund”) seeks to maximize current income.
Expense [Heading]	rr_ExpenseHeading	<b>Fees and Expenses</b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses. You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>Annual Fund Operating Expenses<br/>(ongoing expenses that you pay each year as a<br/>percentage of the value of your investments)</b>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>Portfolio Turnover.</b>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 48% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	48.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>Example.</b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>Principal Investment Strategies</b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in a portfolio of U.S. dollar-denominated investment-grade fixed-income securities. The Fund primarily invests in investment-grade fixed-income securities that are rated BBB- or higher by S&P Global Ratings and/or Fitch Ratings, Inc. (“Fitch”), or Baa3 or higher by Moody’s Investors Service, Inc. (“Moody's”), or, if unrated, determined by the Fund's management team to be of equivalent quality. The Fund primarily invests in fixed- and floating-rate securities of varying maturities, such as corporate and government bonds, agency securities, instruments of non-U.S. issuers, privately-issued securities, asset-backed securities (“ABS”) and mortgage-backed securities (“MBS”), structured securities, municipal bonds, repurchase agreements, money market instruments and investment companies. The Fund invests in securities issued by financial institutions such as banks, broker-dealers and insurance companies. The Fund may enter into to-be-announced transactions (“TBA transactions”) on a regular basis with respect to the percentage of the portfolio (if any) that consists of mortgage-backed pass-through securities. BFA or its affiliates may advise the money market funds and investment companies in which the Fund may invest. Under normal circumstances, the effective duration of the Fund’s portfolio is expected to be one year or less, as calculated by the Fund's management team. Effective duration is a measure of the Fund’s price sensitivity to changes in yields or interest rates; however, investors should be aware that effective duration is not an exact measurement and may not reliably predict a particular security’s price sensitivity to changes in yield or interest rates. Under normal circumstances, the Fund will also 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. For the purposes of determining the Fund’s weighted average maturity, a security’s final maturity date, or for amortizing securities such as asset-backed and mortgage-backed securities, its weighted average life, will be used for calculation purposes. The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index. The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index. The Fund is not a money market fund and does not seek to maintain a stable net asset value of $1.00 per share. Please see the Fund’s Statement of Additional Information (“SAI”) for further information. The Fund may lend securities representing up to one-third of the value of the Fund's total assets (including the value of the collateral received).
Risk [Heading]	rr_RiskHeading	<b>Summary of Principal Risks</b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF. Asset-Backed and Mortgage-Backed Securities Risk. ABS and MBS (residential and commercial) represent interests in “pools” of mortgages or other assets, including consumer loans or receivables held in trust. ABS and MBS are subject to credit, interest rate, call, extension, valuation and liquidity risk. These securities, in most cases, are not backed by the full faith and credit of the U.S. government and are subject to the risk of default on the underlying asset or mortgage, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain ABS and MBS. Asset Class Risk. Securities and other assets in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes. Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of this prospectus (“the Prospectus”)), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund may “call” or repay the security before its stated maturity, and the Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's income, or in securities with greater risks or with other less favorable features. Cash Transactions Risk. The Fund expects to effect all of its creations and redemptions for cash, rather than in-kind securities. As a result, the Fund may have to sell portfolio securities at inopportune times in order to obtain the cash needed to meet redemption orders. This may cause the Fund to sell a security and recognize a capital gain or loss that might not have been incurred if it had made a redemption in-kind. The use of cash creations and redemptions may also cause the Fund’s shares to trade in the market at wider bid-ask spreads or greater premiums or discounts to the Fund’s NAV. Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation. Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers (including the benchmark provider), market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests. Extension Risk. During periods of rising interest rates, certain debt obligations may be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in the Fund’s income and potentially in the value of the Fund’s investments. Floating Rate Notes Risk. Securities with floating or variable interest rates can be less sensitive to interest rate changes than securities with fixed interest rates, but may decline in value if their coupon rates do not reset as high, or as quickly, as comparable market interest rates, and generally carry lower yields than fixed notes of the same maturity. Although floating rate notes are less sensitive to interest rate risk than fixed-rate securities, they are subject to credit risk and default risk, which could impair their value. Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. Income Risk. The Fund’s income may decline when interest rates fall because the Fund may hold a significant portion of short duration securities and/or securities that have floating or variable interest rates. The Fund’s income may decline because the Fund invests in lower yielding bonds, and as the bonds in its portfolio mature, are near maturity or are called, the Fund needs to purchase additional bonds. Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. Issuer Risk. The performance of the Fund depends on the performance of individual securities to which the Fund has exposure. Changes in the financial condition or credit rating of an issuer of those securities may cause the value of the securities to decline. Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. Municipal Securities Risk. Municipal securities can be significantly affected by political or economic changes, including changes made in the law after issuance of the securities, as well as uncertainties in the municipal market related to taxation, legislative changes or the rights of municipal security holders, including in connection with an issuer insolvency. Municipal securities backed by current or anticipated revenues from a specific project or specific assets can be negatively affected by the inability to collect revenues from the project or the assets. Not a Money Market Fund. The Fund is not a money market fund and is not subject to the strict rules that govern the quality, maturity, liquidity and other features of securities that money market funds may purchase. Under normal circumstances, the Fund’s investments may be more susceptible than a money market fund is to credit risk, interest rate risk, valuation risk and other risks relevant to the Fund’s investments. The Fund does not seek to maintain a stable net asset value of $1.00 per share. Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks. Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential. Privately-Issued Securities Risk. 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”). Privately-issued securities are securities that have not been registered under the 1933 Act and as a result may be subject to legal restrictions on resale. Privately-issued securities are generally not traded on established markets. As a result of the absence of a public trading market, privately issued securities may be deemed to be illiquid investments, may be more difficult to value than publicly traded securities and may be subject to wide fluctuations in value. Delay or difficulty in selling such securities may result in a loss to the Fund. Repurchase Agreement Risk. A repurchase agreement is an instrument under which the purchaser (i.e., the Fund) acquires a security and the seller agrees, at the time of the sale, to repurchase the security at a mutually agreed upon time and price. Repurchase agreements may be construed to be collateralized loans by the purchaser to the seller secured by the securities transferred to the purchaser. If a repurchase agreement is construed to be a collateralized loan, the underlying securities will not be considered to be owned by the Fund but only to constitute collateral for the seller’s obligation to pay the repurchase price. If the seller defaults on its obligation under the agreement, the Fund may suffer delays and incur costs or lose money in exercising its rights under the agreement. If the seller fails to repurchase the security and the market value of the security declines, the Fund may lose money. Risk of Investing in the U.S. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure. Securities Lending Risk. The Fund may engage in securities lending. Securities lending involves the risk that the Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund. Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund's valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>Performance Information</b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-800-iShares (1-800-474-2737) (toll free)
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.iShares.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>Year by Year Returns (Years Ended December 31)</b>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The best calendar quarter return during the periods shown above was 0.63% in the 3rd quarter of 2018; the worst was 0.04% in the 4th quarter of 2014. Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).
Performance Table Heading	rr_PerformanceTableHeading	<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”).
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.
iShares Short Maturity Bond ETF | iShares Short Maturity Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.25%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	none
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.25%
1 Year	rr_ExpenseExampleYear01	$ 26
3 Years	rr_ExpenseExampleYear03	80
5 Years	rr_ExpenseExampleYear05	141
10 Years	rr_ExpenseExampleYear10	$ 318
2014	rr_AnnualReturn2014	0.75%
2015	rr_AnnualReturn2015	0.69%
2016	rr_AnnualReturn2016	1.42%
2017	rr_AnnualReturn2017	1.55%
2018	rr_AnnualReturn2018	1.71%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	best
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2018
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.63%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	worst
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2014
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	0.04%
One Year	rr_AverageAnnualReturnYear01	1.71%
Five Years	rr_AverageAnnualReturnYear05	1.22%
Since Fund Inception	rr_AverageAnnualReturnSinceInception	1.22%
Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 25, 2013
iShares Short Maturity Bond ETF | Return After Taxes on Distributions | iShares Short Maturity Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	0.79%	[1]
Five Years	rr_AverageAnnualReturnYear05	0.66%	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	0.68%	[1]
iShares Short Maturity Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares | iShares Short Maturity Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	1.01%	[1]
Five Years	rr_AverageAnnualReturnYear05	0.69%	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	0.69%	[1]
iShares Short Maturity Bond ETF | Bloomberg Barclays Short-Term Government/Corporate Index (Index returns do not reflect deductions for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	1.99%	[2]
Five Years	rr_AverageAnnualReturnYear05	0.84%	[2]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	0.81%	[2]

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[2] The Bloomberg Barclays Short-Term Government/Corporate Index is an unmanaged index that measures the performance of government and corporate securities with less than one year remaining to maturity.

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iShares Short Maturity Municipal Bond ETF

iSHARES^® SHORT MATURITY<br/>MUNICIPAL BOND ETF<br/>Ticker: MEAR                                 Stock Exchange: Cboe BZX

<b>Investment Objective</b>

The iShares Short Maturity Municipal Bond ETF (the “Fund”) seeks to maximize tax-free current income.

<b>Fees and Expenses</b>

The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses.

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

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

Annual Fund Operating Expenses	Management Fees	Distribution and Service (12b-1) Fees	Other Expenses	Total Annual Fund Operating Expenses
iShares Short Maturity Municipal Bond ETF | iShares Short Maturity Municipal Bond ETF	0.25%	none	none	0.25%

<b>Example.</b>

This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example	1 Year	3 Years	5 Years	10 Years
iShares Short Maturity Municipal Bond ETF | iShares Short Maturity Municipal Bond ETF | USD ($)	26	80	141	318

<b>Portfolio Turnover.</b>

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 221% of the average value of its portfolio.

<b>Principal Investment Strategies</b>

The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in municipal securities such that the interest on each bond is exempt from U.S. federal income taxes and the federal alternative minimum tax (“AMT”). Under normal circumstances, the Fund primarily invests in U.S. dollar-denominated investment-grade short-term fixed- and floating-rate municipal securities with remaining maturities of five years or less, such as municipal bonds, municipal notes and variable rate demand obligations, as well as money market instruments and registered investment companies. Investment-grade securities are rated BBB- or higher by S&P Global Ratings and/or Fitch Ratings, Inc. (“Fitch”), or Baa3 or higher by Moody’s Investors Service, Inc. (“Moody's”), or, if unrated, determined by the Fund's management team to be of equivalent quality. Municipal bonds include debt obligations issued by or on behalf of a governmental entity or other qualifying issuer that pay interest that is, in the opinion of bond counsel to the issuer at the time of issuance, generally excludable from gross income for U.S. federal income tax purposes. The Fund may invest up to 20% of its net assets in municipal securities that pay interest that is subject to the federal AMT. Issuers may be states, territories and possessions of the U.S., including the District of Columbia, and their political subdivisions, agencies and instrumentalities. BFA or its affiliates may advise the money market funds and investment companies in which the Fund may invest.

Under normal circumstances, the effective duration of the Fund's portfolio is expected to be 1.2 years or less, as calculated by the Fund's management team, and it is not expected to exceed 1.5 years. Effective duration is a measure of the Fund’s price sensitivity to changes in yields or interest rates; however, investors should be aware that effective duration is not an exact measurement and may not reliably predict a particular security’s price sensitivity to changes in yield or interest rates.

Under normal circumstances, the Fund will also 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. For the purposes of determining the Fund’s weighted average maturity, a security’s final maturity date, or for amortizing securities such as asset-backed and mortgage-backed securities, its weighted average life, will be used for calculation purposes.

The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index. The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index.

The Fund is not a money market fund and does not seek to maintain a stable net asset value of $1.00 per share. Please see the Fund’s Statement of Additional Information (“SAI”) for further information.

<b>Summary of Principal Risks</b>

As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF.

Asset Class Risk. Securities and other assets in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes.

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of this prospectus (“the Prospectus”)), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting.

Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund may “call” or repay the security before its stated maturity, and the Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's income, or in securities with greater risks or with other less favorable features.

Cash Management Risk. If a significant amount of the Fund’s assets are invested in cash and cash equivalents, it will be more difficult for the Fund to achieve its investment objective. The Fund may underperform other funds that do not similarly invest in cash and cash equivalents for investment purposes and/or to collateralize derivative instruments.

Cash Transactions Risk. The Fund expects to effect all of its creations and redemptions for cash, rather than in-kind securities. As a result, the Fund may have to sell portfolio securities at inopportune times in order to obtain the cash needed to meet redemption orders. This may cause the Fund to sell a security and recognize a capital gain or loss that might not have been incurred if it had made a redemption in-kind. The use of cash creations and redemptions may also cause the Fund’s shares to trade in the market at wider bid-ask spreads or greater premiums or discounts to the Fund’s NAV.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class.

Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation.

Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers (including the benchmark provider), market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests.

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

Floating Rate Notes Risk. Securities with floating or variable interest rates can be less sensitive to interest rate changes than securities with fixed interest rates, but may decline in value if their coupon rates do not reset as high, or as quickly, as comparable market interest rates, and generally carry lower yields than fixed notes of the same maturity. Although floating rate notes are less sensitive to interest rate risk than fixed-rate securities, they are subject to credit risk and default risk, which could impair their value.

High Portfolio Turnover Risk. The Fund may engage in active and frequent trading of its portfolio securities. High portfolio turnover (considered by the Fund to mean higher than 100% annually) may result in increased transaction costs to the Fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of the securities and on reinvestment in other securities.

Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices.

Income Risk. The Fund’s income may decline when interest rates fall because the Fund may hold a significant portion of short duration securities and/or securities that have floating or variable interest rates. The Fund’s income may decline because the Fund invests in lower yielding bonds, and as the bonds in its portfolio mature, are near maturity or are called, the Fund needs to purchase additional bonds.

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

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

Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective.

Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns.

Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

Municipal Securities Risk. Municipal securities can be significantly affected by political or economic changes, including changes made in the law after issuance of the securities, as well as uncertainties in the municipal market related to taxation, legislative changes or the rights of municipal security holders, including in connection with an issuer insolvency. Municipal securities backed by current or anticipated revenues from a specific project or specific assets can be negatively affected by the inability to collect revenues from the project or the assets.

Not a Money Market Fund. The Fund is not a money market fund and is not subject to the strict rules that govern the quality, maturity, liquidity and other features of securities that money market funds may purchase. Under normal circumstances, the Fund’s investments may be more susceptible than a money market fund is to credit risk, interest rate risk, valuation risk and other risks relevant to the Fund’s investments. The Fund does not seek to maintain a stable net asset value of $1.00 per share.

Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Privately-Issued Securities Risk. 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”). Privately-issued securities are securities that have not been registered under the 1933 Act and as a result may be subject to legal restrictions on resale. Privately-issued securities are generally not traded on established markets. As a result of the absence of a public trading market, privately issued securities may be deemed to be illiquid investments, may be more difficult to value than publicly traded securities and may be subject to wide fluctuations in value. Delay or difficulty in selling such securities may result in a loss to the Fund.

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

Tax Risk. There is no guarantee that the Fund's income will be exempt from U.S. federal income taxes, the federal AMT or the federal Medicare contribution tax of 3.8% on “net investment income.”

Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund's valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.

<b>Performance Information</b>

The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.

<b>Year by Year Returns (Years Ended December 31)</b>

The best calendar quarter return during the periods shown above was 0.54% in the 1st quarter of 2017; the worst was -0.17% in the 4th quarter of 2017.

Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).

<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>

Average Annual Total Returns - iShares Short Maturity Municipal Bond ETF		One Year	Since Fund Inception	Inception Date
iShares Short Maturity Municipal Bond ETF		1.58%	0.91%	Mar. 03, 2015
iShares Short Maturity Municipal Bond ETF | Return After Taxes on Distributions	[1]	1.58%	0.91%
iShares Short Maturity Municipal Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares	[1]	1.50%	0.93%
Bloomberg Barclays Municipal Bond: 1 Year (1-2) Index (Index returns do not reflect deductions for fees, expenses, or taxes)	[2]	1.74%	0.87%

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[2] The Bloomberg Barclays Municipal Bond: 1 Year (1-2) Index is an unmanaged index comprised of national municipal bond issues having a maturity of at least one year and less than two years.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	iShares U.S. ETF Trust
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
iShares Short Maturity Municipal Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	iSHARES<sup>®</sup> SHORT MATURITY<br/>MUNICIPAL BOND ETF<br/>Ticker: MEAR                                 Stock Exchange: Cboe BZX
Objective [Heading]	rr_ObjectiveHeading	<b>Investment Objective</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The iShares Short Maturity Municipal Bond ETF (the “Fund”) seeks to maximize tax-free current income.
Expense [Heading]	rr_ExpenseHeading	<b>Fees and Expenses</b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses. You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>Annual Fund Operating Expenses<br/>(ongoing expenses that you pay each year as a<br/>percentage of the value of your investments) </b>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>Portfolio Turnover.</b>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 221% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	221.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>Example.</b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>Principal Investment Strategies</b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in municipal securities such that the interest on each bond is exempt from U.S. federal income taxes and the federal alternative minimum tax (“AMT”). Under normal circumstances, the Fund primarily invests in U.S. dollar-denominated investment-grade short-term fixed- and floating-rate municipal securities with remaining maturities of five years or less, such as municipal bonds, municipal notes and variable rate demand obligations, as well as money market instruments and registered investment companies. Investment-grade securities are rated BBB- or higher by S&P Global Ratings and/or Fitch Ratings, Inc. (“Fitch”), or Baa3 or higher by Moody’s Investors Service, Inc. (“Moody's”), or, if unrated, determined by the Fund's management team to be of equivalent quality. Municipal bonds include debt obligations issued by or on behalf of a governmental entity or other qualifying issuer that pay interest that is, in the opinion of bond counsel to the issuer at the time of issuance, generally excludable from gross income for U.S. federal income tax purposes. The Fund may invest up to 20% of its net assets in municipal securities that pay interest that is subject to the federal AMT. Issuers may be states, territories and possessions of the U.S., including the District of Columbia, and their political subdivisions, agencies and instrumentalities. BFA or its affiliates may advise the money market funds and investment companies in which the Fund may invest. Under normal circumstances, the effective duration of the Fund's portfolio is expected to be 1.2 years or less, as calculated by the Fund's management team, and it is not expected to exceed 1.5 years. Effective duration is a measure of the Fund’s price sensitivity to changes in yields or interest rates; however, investors should be aware that effective duration is not an exact measurement and may not reliably predict a particular security’s price sensitivity to changes in yield or interest rates. Under normal circumstances, the Fund will also 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. For the purposes of determining the Fund’s weighted average maturity, a security’s final maturity date, or for amortizing securities such as asset-backed and mortgage-backed securities, its weighted average life, will be used for calculation purposes. The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index. The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index. The Fund is not a money market fund and does not seek to maintain a stable net asset value of $1.00 per share. Please see the Fund’s Statement of Additional Information (“SAI”) for further information.
Risk [Heading]	rr_RiskHeading	<b>Summary of Principal Risks</b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF. Asset Class Risk. Securities and other assets in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes. Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of this prospectus (“the Prospectus”)), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund may “call” or repay the security before its stated maturity, and the Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's income, or in securities with greater risks or with other less favorable features. Cash Management Risk. If a significant amount of the Fund’s assets are invested in cash and cash equivalents, it will be more difficult for the Fund to achieve its investment objective. The Fund may underperform other funds that do not similarly invest in cash and cash equivalents for investment purposes and/or to collateralize derivative instruments. Cash Transactions Risk. The Fund expects to effect all of its creations and redemptions for cash, rather than in-kind securities. As a result, the Fund may have to sell portfolio securities at inopportune times in order to obtain the cash needed to meet redemption orders. This may cause the Fund to sell a security and recognize a capital gain or loss that might not have been incurred if it had made a redemption in-kind. The use of cash creations and redemptions may also cause the Fund’s shares to trade in the market at wider bid-ask spreads or greater premiums or discounts to the Fund’s NAV. Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation. Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers (including the benchmark provider), market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests. Extension Risk. During periods of rising interest rates, certain debt obligations may be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in the Fund’s income and potentially in the value of the Fund’s investments. Floating Rate Notes Risk. Securities with floating or variable interest rates can be less sensitive to interest rate changes than securities with fixed interest rates, but may decline in value if their coupon rates do not reset as high, or as quickly, as comparable market interest rates, and generally carry lower yields than fixed notes of the same maturity. Although floating rate notes are less sensitive to interest rate risk than fixed-rate securities, they are subject to credit risk and default risk, which could impair their value. High Portfolio Turnover Risk. The Fund may engage in active and frequent trading of its portfolio securities. High portfolio turnover (considered by the Fund to mean higher than 100% annually) may result in increased transaction costs to the Fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of the securities and on reinvestment in other securities. Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. Income Risk. The Fund’s income may decline when interest rates fall because the Fund may hold a significant portion of short duration securities and/or securities that have floating or variable interest rates. The Fund’s income may decline because the Fund invests in lower yielding bonds, and as the bonds in its portfolio mature, are near maturity or are called, the Fund needs to purchase additional bonds. Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. Issuer Risk. The performance of the Fund depends on the performance of individual securities to which the Fund has exposure. Changes in the financial condition or credit rating of an issuer of those securities may cause the value of the securities to decline. Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. Municipal Securities Risk. Municipal securities can be significantly affected by political or economic changes, including changes made in the law after issuance of the securities, as well as uncertainties in the municipal market related to taxation, legislative changes or the rights of municipal security holders, including in connection with an issuer insolvency. Municipal securities backed by current or anticipated revenues from a specific project or specific assets can be negatively affected by the inability to collect revenues from the project or the assets. Not a Money Market Fund. The Fund is not a money market fund and is not subject to the strict rules that govern the quality, maturity, liquidity and other features of securities that money market funds may purchase. Under normal circumstances, the Fund’s investments may be more susceptible than a money market fund is to credit risk, interest rate risk, valuation risk and other risks relevant to the Fund’s investments. The Fund does not seek to maintain a stable net asset value of $1.00 per share. Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks. Privately-Issued Securities Risk. 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”). Privately-issued securities are securities that have not been registered under the 1933 Act and as a result may be subject to legal restrictions on resale. Privately-issued securities are generally not traded on established markets. As a result of the absence of a public trading market, privately issued securities may be deemed to be illiquid investments, may be more difficult to value than publicly traded securities and may be subject to wide fluctuations in value. Delay or difficulty in selling such securities may result in a loss to the Fund. Risk of Investing in the U.S. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure. Tax Risk. There is no guarantee that the Fund's income will be exempt from U.S. federal income taxes, the federal AMT or the federal Medicare contribution tax of 3.8% on “net investment income.” Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund's valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>Performance Information</b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-800-iShares (1-800-474-2737) (toll free)
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.iShares.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>Year by Year Returns (Years Ended December 31)</b>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The best calendar quarter return during the periods shown above was 0.54% in the 1st quarter of 2017; the worst was -0.17% in the 4th quarter of 2017. Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).
Performance Table Heading	rr_PerformanceTableHeading	<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”).
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.
iShares Short Maturity Municipal Bond ETF | iShares Short Maturity Municipal Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.25%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	none
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.25%
1 Year	rr_ExpenseExampleYear01	$ 26
3 Years	rr_ExpenseExampleYear03	80
5 Years	rr_ExpenseExampleYear05	141
10 Years	rr_ExpenseExampleYear10	$ 318
2016	rr_AnnualReturn2016	0.59%
2017	rr_AnnualReturn2017	0.97%
2018	rr_AnnualReturn2018	1.58%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	best
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Mar. 31, 2017
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.54%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	worst
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2017
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(0.17%)
One Year	rr_AverageAnnualReturnYear01	1.58%
Since Fund Inception	rr_AverageAnnualReturnSinceInception	0.91%
Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 03, 2015
iShares Short Maturity Municipal Bond ETF | Return After Taxes on Distributions | iShares Short Maturity Municipal Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	1.58%	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	0.91%	[1]
iShares Short Maturity Municipal Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares | iShares Short Maturity Municipal Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	1.50%	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	0.93%	[1]
iShares Short Maturity Municipal Bond ETF | Bloomberg Barclays Municipal Bond: 1 Year (1-2) Index (Index returns do not reflect deductions for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	1.74%	[2]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	0.87%	[2]

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[2] The Bloomberg Barclays Municipal Bond: 1 Year (1-2) Index is an unmanaged index comprised of national municipal bond issues having a maturity of at least one year and less than two years.

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iShares Ultra Short-Term Bond ETF

iSHARES^® ULTRA SHORT-TERM BOND ETF<br/>Ticker: ICSH                                 Stock Exchange: Cboe BZX

<b>Investment Objective</b>

The iShares Ultra Short-Term Bond ETF (the “Fund”) seeks to provide current income consistent with preservation of capital.

<b>Fees and Expenses</b>

The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses.

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

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

Annual Fund Operating Expenses	Management Fees	Distribution and Service (12b-1) Fees	Other Expenses	Total Annual Fund Operating Expenses
iShares Ultra Short-Term Bond ETF | iShares Ultra Short-Term Bond ETF	0.08%	none	none	0.08%

<b>Example.</b>

This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example	1 Year	3 Years	5 Years	10 Years
iShares Ultra Short-Term Bond ETF | iShares Ultra Short-Term Bond ETF | USD ($)	8	26	45	103

<b>Portfolio Turnover.</b>

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 32% of the average value of its portfolio.

<b>Principal Investment Strategies</b>

The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in a portfolio of U.S. dollar-denominated investment-grade fixed- and floating-rate debt securities that are rated BBB- or higher by S&P Global Ratings and/or Fitch Ratings, Inc. (“Fitch”), or Baa3 or higher by Moody’s Investors Service, Inc. (“Moody’s”), or, if unrated, determined by BFA to be of equivalent quality. Under normal circumstances, the Fund will invest primarily in fixed- and floating-rate securities maturing in three years or less. Short-term investments (generally, securities with original maturities of one year or less) held by the Fund will carry a rating in one of the highest two rating categories of at least one nationally recognized statistical ratings organization (“NRSRO”) (e.g., A-2, P-2 or F2 or better by S&P Global Ratings, Moody’s or Fitch, respectively), or if such investments are unrated, determined to be of comparable quality by the Fund's management team, at the time of investment.

The Fund may invest in corporate and U.S. and non-U.S. government bonds, agency securities, instruments of non-U.S. issuers, privately-issued securities, asset-backed securities (“ABS”) and mortgage-backed securities (“MBS”), structured securities, municipal bonds, repurchase agreements, money market instruments and investment companies (including investment companies advised by BFA or its affiliates). The Fund invests a significant portion of its assets in securities issued by financial institutions, such as banks, broker-dealers and insurance companies.

Under normal circumstances, the dollar-weighted average life of the Fund’s portfolio is expected to be one year or less, as calculated by the Fund's management team. The Fund will also seek to maintain a dollar-weighted average maturity that is less than 180 days. “Dollar-weighted average life,” or “WAL,” is the weighted average of the times when principal is to be repaid. “Dollar-weighted average maturity,” or “WAM,” is calculated by taking the average length of time to maturity (fixed-rate) or the next interest rate reset (floating-rate) for each underlying instrument held by the Fund, weighted according to the relative holdings per instrument.

The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index. The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index.

The Fund is not a money market fund and does not seek to maintain a stable net asset value of $1.00 per share. Please see the Fund's Statement of Additional Information (“SAI”) for further information.

<b>Summary of Principal Risks</b>

As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF.

Agency Debt Risk. The Fund invests in unsecured bonds or debentures issued by U.S. government agencies, including the Federal National Mortgage Association (“Fannie Mae”) and the Federal Home Loan Mortgage Corporation (“Freddie Mac”). Bonds or debentures issued by U.S. government agencies, government-sponsored entities, or government corporations, including, among others, Fannie Mae and Freddie Mac, are generally backed only by the general creditworthiness and reputation of the U.S. government agency, government-sponsored entity, or government corporation issuing the bond or debenture and are not guaranteed by the U.S. Department of the Treasury (“U.S. Treasury”) or backed by the full faith and credit of the U.S. government. As a result, there is uncertainty as to the current status of many obligations of Fannie Mae, Freddie Mac and other agencies that are under conservatorship of the U.S. government. Government National Mortgage Association (“Ginnie Mae”) securities are generally backed by the full faith and credit of the U.S. government.

Asset-Backed and Mortgage-Backed Securities Risk. ABS and MBS (residential and commercial) represent interests in “pools” of mortgages or other assets, including consumer loans or receivables held in trust. ABS and MBS are subject to credit, interest rate, call, extension, valuation and liquidity risk. These securities, in most cases, are not backed by the full faith and credit of the U.S. government and are subject to the risk of default on the underlying asset or mortgage, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain ABS and MBS.

Asset Class Risk. Securities and other assets in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes.

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of this prospectus (“the Prospectus”)), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting.

Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund may “call” or repay the security before its stated maturity, and the Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's income, or in securities with greater risks or with other less favorable features.

Cash Management Risk. If a significant amount of the Fund’s assets are invested in cash and cash equivalents, it will be more difficult for the Fund to achieve its investment objective. The Fund may underperform other funds that do not similarly invest in cash and cash equivalents for investment purposes and/or to collateralize derivative instruments.

Cash Transactions Risk. The Fund expects to effect all of its creations and redemptions for cash, rather than in-kind securities. As a result, the Fund may have to sell portfolio securities at inopportune times in order to obtain the cash needed to meet redemption orders. This may cause the Fund to sell a security and recognize a capital gain or loss that might not have been incurred if it had made a redemption in-kind. The use of cash creations and redemptions may also cause the Fund’s shares to trade in the market at wider bid-ask spreads or greater premiums or discounts to the Fund’s NAV.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class.

Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation.

Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers (including the benchmark provider), market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests.

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

Financials Sector Risk. Performance of companies in the financials sector may be adversely impacted by many factors, including, among others, changes in government regulations, economic conditions, and interest rates, credit rating downgrades, and decreased liquidity in credit markets. The extent to which the Fund may invest in a company that engages in securities-related activities or banking is limited by applicable law. The impact of changes in capital requirements and recent or future regulation of any individual financial company, or of the financials sector as a whole, cannot be predicted. In recent years, cyber-attacks and technology malfunctions and failures have become increasingly frequent in this sector and have caused significant losses to companies in this sector, which may negatively impact the Fund.

Floating Rate Notes Risk. Securities with floating or variable interest rates can be less sensitive to interest rate changes than securities with fixed interest rates, but may decline in value if their coupon rates do not reset as high, or as quickly, as comparable market interest rates, and generally carry lower yields than fixed notes of the same maturity. Although floating rate notes are less sensitive to interest rate risk than fixed-rate securities, they are subject to credit risk and default risk, which could impair their value.

Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices.

Income Risk. The Fund’s income may decline when interest rates fall because the Fund may hold a significant portion of short duration securities and/or securities that have floating or variable interest rates. The Fund’s income may decline because the Fund invests in lower yielding bonds, and as the bonds in its portfolio mature, are near maturity or are called, the Fund needs to purchase additional bonds.

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

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

Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective.

Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns.

Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

Municipal Securities Risk. Municipal securities can be significantly affected by political or economic changes, including changes made in the law after issuance of the securities, as well as uncertainties in the municipal market related to taxation, legislative changes or the rights of municipal security holders, including in connection with an issuer insolvency. Municipal securities backed by current or anticipated revenues from a specific project or specific assets can be negatively affected by the inability to collect revenues from the project or the assets.

Not a Money Market Fund. The Fund is not a money market fund and is not subject to the strict rules that govern the quality, maturity, liquidity and other features of securities that money market funds may purchase. Under normal circumstances, the Fund’s investments may be more susceptible than a money market fund is to credit risk, interest rate risk, valuation risk and other risks relevant to the Fund’s investments. The Fund does not seek to maintain a stable net asset value of $1.00 per share.

Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Privately-Issued Securities Risk. 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”). Privately-issued securities are securities that have not been registered under the 1933 Act and as a result may be subject to legal restrictions on resale. Privately-issued securities are generally not traded on established markets. As a result of the absence of a public trading market, privately issued securities may be deemed to be illiquid investments, may be more difficult to value than publicly traded securities and may be subject to wide fluctuations in value. Delay or difficulty in selling such securities may result in a loss to the Fund.

Repurchase Agreement Risk. A repurchase agreement is an instrument under which the purchaser (i.e., the Fund) acquires a security and the seller agrees, at the time of the sale, to repurchase the security at a mutually agreed upon time and price. Repurchase agreements may be construed to be collateralized loans by the purchaser to the seller secured by the securities transferred to the purchaser. If a repurchase agreement is construed to be a collateralized loan, the underlying securities will not be considered to be owned by the Fund but only to constitute collateral for the seller’s obligation to pay the repurchase price. If the seller defaults on its obligation under the agreement, the Fund may suffer delays and incur costs or lose money in exercising its rights under the agreement. If the seller fails to repurchase the security and the market value of the security declines, the Fund may lose money.

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

Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund's valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.

<b>Performance Information</b>

The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus.

<b>Year by Year Returns (Years Ended December 31)</b>

The best calendar quarter return during the periods shown above was 0.69% in the 3rd quarter of 2018; the worst was -0.06% in the 3rd quarter of 2015.

Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).

<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>

Average Annual Total Returns - iShares Ultra Short-Term Bond ETF		One Year	Five Years	Since Fund Inception	Inception Date
iShares Ultra Short-Term Bond ETF		2.26%	1.12%	1.10%	Dec. 11, 2013
iShares Ultra Short-Term Bond ETF | Return After Taxes on Distributions	[1]	1.35%	0.65%	0.65%
iShares Ultra Short-Term Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares	[1]	1.33%	0.65%	0.64%
ICE BofAML 6-Month US Treasury Bill Index (Index returns do not reflect deductions for fees, expenses or taxes)	[2]	1.92%	0.78%	0.77%

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[2] The ICE BofAML 6-Month US Treasury Bill Index is an unmanaged index that measures the performance of government securities with less than six months remaining to maturity.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	iShares U.S. ETF Trust
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
iShares Ultra Short-Term Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	iSHARES<sup>®</sup> ULTRA SHORT-TERM BOND ETF<br/>Ticker: ICSH                                 Stock Exchange: Cboe BZX
Objective [Heading]	rr_ObjectiveHeading	<b>Investment Objective</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The iShares Ultra Short-Term Bond ETF (the “Fund”) seeks to provide current income consistent with preservation of capital.
Expense [Heading]	rr_ExpenseHeading	<b>Fees and Expenses</b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses. You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>Annual Fund Operating Expenses<br/>(ongoing expenses that you pay each year as a<br/>percentage of the value of your investments) </b>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>Portfolio Turnover.</b>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 32% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	32.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>Example.</b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>Principal Investment Strategies</b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in a portfolio of U.S. dollar-denominated investment-grade fixed- and floating-rate debt securities that are rated BBB- or higher by S&P Global Ratings and/or Fitch Ratings, Inc. (“Fitch”), or Baa3 or higher by Moody’s Investors Service, Inc. (“Moody’s”), or, if unrated, determined by BFA to be of equivalent quality. Under normal circumstances, the Fund will invest primarily in fixed- and floating-rate securities maturing in three years or less. Short-term investments (generally, securities with original maturities of one year or less) held by the Fund will carry a rating in one of the highest two rating categories of at least one nationally recognized statistical ratings organization (“NRSRO”) (e.g., A-2, P-2 or F2 or better by S&P Global Ratings, Moody’s or Fitch, respectively), or if such investments are unrated, determined to be of comparable quality by the Fund's management team, at the time of investment. The Fund may invest in corporate and U.S. and non-U.S. government bonds, agency securities, instruments of non-U.S. issuers, privately-issued securities, asset-backed securities (“ABS”) and mortgage-backed securities (“MBS”), structured securities, municipal bonds, repurchase agreements, money market instruments and investment companies (including investment companies advised by BFA or its affiliates). The Fund invests a significant portion of its assets in securities issued by financial institutions, such as banks, broker-dealers and insurance companies. Under normal circumstances, the dollar-weighted average life of the Fund’s portfolio is expected to be one year or less, as calculated by the Fund's management team. The Fund will also seek to maintain a dollar-weighted average maturity that is less than 180 days. “Dollar-weighted average life,” or “WAL,” is the weighted average of the times when principal is to be repaid. “Dollar-weighted average maturity,” or “WAM,” is calculated by taking the average length of time to maturity (fixed-rate) or the next interest rate reset (floating-rate) for each underlying instrument held by the Fund, weighted according to the relative holdings per instrument. The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index. The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index. The Fund is not a money market fund and does not seek to maintain a stable net asset value of $1.00 per share. Please see the Fund's Statement of Additional Information (“SAI”) for further information.
Risk [Heading]	rr_RiskHeading	<b>Summary of Principal Risks</b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF. Agency Debt Risk. The Fund invests in unsecured bonds or debentures issued by U.S. government agencies, including the Federal National Mortgage Association (“Fannie Mae”) and the Federal Home Loan Mortgage Corporation (“Freddie Mac”). Bonds or debentures issued by U.S. government agencies, government-sponsored entities, or government corporations, including, among others, Fannie Mae and Freddie Mac, are generally backed only by the general creditworthiness and reputation of the U.S. government agency, government-sponsored entity, or government corporation issuing the bond or debenture and are not guaranteed by the U.S. Department of the Treasury (“U.S. Treasury”) or backed by the full faith and credit of the U.S. government. As a result, there is uncertainty as to the current status of many obligations of Fannie Mae, Freddie Mac and other agencies that are under conservatorship of the U.S. government. Government National Mortgage Association (“Ginnie Mae”) securities are generally backed by the full faith and credit of the U.S. government. Asset-Backed and Mortgage-Backed Securities Risk. ABS and MBS (residential and commercial) represent interests in “pools” of mortgages or other assets, including consumer loans or receivables held in trust. ABS and MBS are subject to credit, interest rate, call, extension, valuation and liquidity risk. These securities, in most cases, are not backed by the full faith and credit of the U.S. government and are subject to the risk of default on the underlying asset or mortgage, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain ABS and MBS. Asset Class Risk. Securities and other assets in the Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes. Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of this prospectus (“the Prospectus”)), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund may “call” or repay the security before its stated maturity, and the Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's income, or in securities with greater risks or with other less favorable features. Cash Management Risk. If a significant amount of the Fund’s assets are invested in cash and cash equivalents, it will be more difficult for the Fund to achieve its investment objective. The Fund may underperform other funds that do not similarly invest in cash and cash equivalents for investment purposes and/or to collateralize derivative instruments. Cash Transactions Risk. The Fund expects to effect all of its creations and redemptions for cash, rather than in-kind securities. As a result, the Fund may have to sell portfolio securities at inopportune times in order to obtain the cash needed to meet redemption orders. This may cause the Fund to sell a security and recognize a capital gain or loss that might not have been incurred if it had made a redemption in-kind. The use of cash creations and redemptions may also cause the Fund’s shares to trade in the market at wider bid-ask spreads or greater premiums or discounts to the Fund’s NAV. Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's investments are concentrated in the securities of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation. Cyber Security Risk. Failures or breaches of the electronic systems of the Fund, the Fund's adviser, distributor, and other service providers (including the benchmark provider), market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests. Extension Risk. During periods of rising interest rates, certain debt obligations may be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in the Fund’s income and potentially in the value of the Fund’s investments. Financials Sector Risk. Performance of companies in the financials sector may be adversely impacted by many factors, including, among others, changes in government regulations, economic conditions, and interest rates, credit rating downgrades, and decreased liquidity in credit markets. The extent to which the Fund may invest in a company that engages in securities-related activities or banking is limited by applicable law. The impact of changes in capital requirements and recent or future regulation of any individual financial company, or of the financials sector as a whole, cannot be predicted. In recent years, cyber-attacks and technology malfunctions and failures have become increasingly frequent in this sector and have caused significant losses to companies in this sector, which may negatively impact the Fund. Floating Rate Notes Risk. Securities with floating or variable interest rates can be less sensitive to interest rate changes than securities with fixed interest rates, but may decline in value if their coupon rates do not reset as high, or as quickly, as comparable market interest rates, and generally carry lower yields than fixed notes of the same maturity. Although floating rate notes are less sensitive to interest rate risk than fixed-rate securities, they are subject to credit risk and default risk, which could impair their value. Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. Income Risk. The Fund’s income may decline when interest rates fall because the Fund may hold a significant portion of short duration securities and/or securities that have floating or variable interest rates. The Fund’s income may decline because the Fund invests in lower yielding bonds, and as the bonds in its portfolio mature, are near maturity or are called, the Fund needs to purchase additional bonds. Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. Issuer Risk. The performance of the Fund depends on the performance of individual securities to which the Fund has exposure. Changes in the financial condition or credit rating of an issuer of those securities may cause the value of the securities to decline. Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. Municipal Securities Risk. Municipal securities can be significantly affected by political or economic changes, including changes made in the law after issuance of the securities, as well as uncertainties in the municipal market related to taxation, legislative changes or the rights of municipal security holders, including in connection with an issuer insolvency. Municipal securities backed by current or anticipated revenues from a specific project or specific assets can be negatively affected by the inability to collect revenues from the project or the assets. Not a Money Market Fund. The Fund is not a money market fund and is not subject to the strict rules that govern the quality, maturity, liquidity and other features of securities that money market funds may purchase. Under normal circumstances, the Fund’s investments may be more susceptible than a money market fund is to credit risk, interest rate risk, valuation risk and other risks relevant to the Fund’s investments. The Fund does not seek to maintain a stable net asset value of $1.00 per share. Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks. Privately-Issued Securities Risk. 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”). Privately-issued securities are securities that have not been registered under the 1933 Act and as a result may be subject to legal restrictions on resale. Privately-issued securities are generally not traded on established markets. As a result of the absence of a public trading market, privately issued securities may be deemed to be illiquid investments, may be more difficult to value than publicly traded securities and may be subject to wide fluctuations in value. Delay or difficulty in selling such securities may result in a loss to the Fund. Repurchase Agreement Risk. A repurchase agreement is an instrument under which the purchaser (i.e., the Fund) acquires a security and the seller agrees, at the time of the sale, to repurchase the security at a mutually agreed upon time and price. Repurchase agreements may be construed to be collateralized loans by the purchaser to the seller secured by the securities transferred to the purchaser. If a repurchase agreement is construed to be a collateralized loan, the underlying securities will not be considered to be owned by the Fund but only to constitute collateral for the seller’s obligation to pay the repurchase price. If the seller defaults on its obligation under the agreement, the Fund may suffer delays and incur costs or lose money in exercising its rights under the agreement. If the seller fails to repurchase the security and the market value of the security declines, the Fund may lose money. Risk of Investing in the U.S. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure. Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund's valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. In addition, the value of the securities or other assets in the Fund's portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund's shares. Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued securities or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>Performance Information</b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-800-iShares (1-800-474-2737) (toll free)
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.iShares.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>Year by Year Returns (Years Ended December 31)</b>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The best calendar quarter return during the periods shown above was 0.69% in the 3rd quarter of 2018; the worst was -0.06% in the 3rd quarter of 2015. Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).
Performance Table Heading	rr_PerformanceTableHeading	<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”).
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.
iShares Ultra Short-Term Bond ETF | iShares Ultra Short-Term Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.08%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	none
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.08%
1 Year	rr_ExpenseExampleYear01	$ 8
3 Years	rr_ExpenseExampleYear03	26
5 Years	rr_ExpenseExampleYear05	45
10 Years	rr_ExpenseExampleYear10	$ 103
2014	rr_AnnualReturn2014	0.44%
2015	rr_AnnualReturn2015	0.17%
2016	rr_AnnualReturn2016	1.19%
2017	rr_AnnualReturn2017	1.53%
2018	rr_AnnualReturn2018	2.26%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	best
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2018
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.69%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	worst
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(0.06%)
One Year	rr_AverageAnnualReturnYear01	2.26%
Five Years	rr_AverageAnnualReturnYear05	1.12%
Since Fund Inception	rr_AverageAnnualReturnSinceInception	1.10%
Inception Date	rr_AverageAnnualReturnInceptionDate	Dec. 11, 2013
iShares Ultra Short-Term Bond ETF | Return After Taxes on Distributions | iShares Ultra Short-Term Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	1.35%	[1]
Five Years	rr_AverageAnnualReturnYear05	0.65%	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	0.65%	[1]
iShares Ultra Short-Term Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares | iShares Ultra Short-Term Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	1.33%	[1]
Five Years	rr_AverageAnnualReturnYear05	0.65%	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	0.64%	[1]
iShares Ultra Short-Term Bond ETF | ICE BofAML 6-Month US Treasury Bill Index (Index returns do not reflect deductions for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	1.92%	[2]
Five Years	rr_AverageAnnualReturnYear05	0.78%	[2]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	0.77%	[2]

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[2] The ICE BofAML 6-Month US Treasury Bill Index is an unmanaged index that measures the performance of government securities with less than six months remaining to maturity.

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iShares Interest Rate Hedged Long-Term Corporate Bond ETF

iSHARES^® INTEREST RATE HEDGED LONG-TERM CORPORATE BOND ETF<br/>Ticker: IGBH                                 Stock Exchange: NYSE Arca

<b>Investment Objective</b>

The iShares Interest Rate Hedged Long-Term Corporate Bond ETF (the “Fund”) seeks to mitigate the interest rate risk of a portfolio composed of U.S. dollar-denominated investment-grade corporate bonds with remaining maturities greater than ten years.

<b>Fees and Expenses</b>

The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”). BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees so that the Fund’s total annual fund operating expenses after fee waiver is equal to the Acquired Fund Fees and Expenses attributable to the Fund’s investment in the iShares Long-Term Corporate Bond ETF (“IGLB” or the “Underlying Fund”), after taking into account any fee waivers by IGLB, plus 0.10% through February 28, 2022. The contractual waiver may be terminated prior to February 28, 2022 only upon written agreement of the Trust and BFA.

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

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

Annual Fund Operating Expenses	Management Fees	Distribution and Service (12b-1) Fees	Other Expenses	Acquired Fund Fees and Expenses	Total Annual Fund Operating Expenses	Fee Waiver	Total Annual Fund Operating Expenses After Fee Waiver
iShares Interest Rate Hedged Long-Term Corporate Bond ETF | iShares Interest Rate Hedged Long-Term Corporate Bond ETF	0.35%	none	none	0.06%	0.41%	(0.25%)	0.16%

<b>Example.</b>

This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example	1 Year	3 Years	5 Years	10 Years
iShares Interest Rate Hedged Long-Term Corporate Bond ETF | iShares Interest Rate Hedged Long-Term Corporate Bond ETF | USD ($)	16	52	150	440

<b>Portfolio Turnover.</b>

The Fund and the Underlying Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate for the Fund or the Underlying Fund may indicate higher transaction costs and may cause the Fund or the Underlying Fund to incur increased expenses. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example (except costs to the Underlying Fund included as part of Acquired Fund Fees and Expenses), affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 5% of the average value of its portfolio. To the extent the Underlying Fund incurs costs from high portfolio turnover, such costs may have a negative effect on the performance of the Fund.

<b>Principal Investment Strategies</b>

The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in U.S. dollar-denominated investment-grade corporate bonds with remaining maturities greater than ten years, in one or more underlying funds that principally invest in U.S. dollar-denominated investment-grade corporate bonds. The Fund intends to invest a substantial portion of its assets in one underlying fund, the Underlying Fund. The Fund attempts to mitigate the interest rate risk of the underlying securities and/or the Underlying Fund (as determined by BFA) primarily through the use of positions in both U.S. Treasury futures contracts and interest rate swaps (i.e., enter into a contract or contracts in which the Fund will make fixed-rate payments while receiving floating-rate payments based on a reference rate). The bonds in which the Fund and/or the Underlying Fund invest may include U.S. dollar-denominated investment-grade corporate bonds, including those of non-U.S. corporations, and generally have at least ten years until maturity at the time of investment. The Fund may also invest in other interest rate futures contracts, including but not limited to, Eurodollar and Federal Funds futures. The Fund’s futures and interest rate swap positions are not intended to mitigate credit risk or other factors influencing the price of investment-grade corporate bonds, which may have a greater impact than interest rates. Under normal circumstances, the Fund and the Underlying Fund will seek to maintain a weighted average maturity that is greater than ten years. Weighted average maturity is a U.S. dollar-weighted average of the remaining term to maturity of the underlying securities in the Underlying Fund's portfolio.

The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index.

The Fund may also invest in other ETFs (including other iShares funds), U.S. government securities, options and swap contracts, short-term paper, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates. The Underlying Fund may invest up to 10% of its assets in certain futures, options and swap contracts, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates.

The CFTC has adopted certain requirements that subject registered investment companies and their advisers to regulation by the CFTC if a registered investment company invests more than a prescribed level of its net asset value in CFTC-regulated futures, options and swaps, or if a registered investment company markets itself as providing investment exposure to such instruments. Due to the Fund’s potential use of CFTC-regulated futures, options and swaps above the prescribed levels, it is considered a “commodity pool” under the Commodity Exchange Act (“CEA”).

The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index.

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).

<b>Summary of Principal Risks</b>

As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below (either directly or through its investments in the Underlying Fund), any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF.

Asset Class Risk. Securities and other assets in the Fund's or the Underlying Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes.

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

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of the Prospectus), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes.

Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund or the Underlying Fund may “call” or repay the security before its stated maturity, and the Fund or the Underlying Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's or Underlying Fund's income, or in securities with greater risks or with other less favorable features.

Commodity Regulatory Risk. The Fund is deemed a commodity pool and BFA is considered a “commodity pool operator” with respect to the Fund under the CEA. BFA is therefore subject to regulation by the SEC and the CFTC. BFA is also subject to regulation by National Futures Association (“NFA”). The regulatory requirements governing the use of commodity futures, options on commodity futures, certain swaps or certain other investments could change at any time.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's or the Underlying Fund's investments are concentrated in the securities of a particular issuer or issuers, in a particular country, group of countries, region, market, industry, group of industries, sector or asset class.

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

Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s or Underlying Fund's investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation.

Cyber Security Risk. Failures or breaches of the electronic systems of the Fund or the Underlying Fund, the Fund's or the Underlying Fund's adviser, distributor, or other service providers (including the benchmark provider), market makers, Authorized Participants, hedging counterparties to the Fund or the issuers of securities in which the Fund or the Underlying Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants, hedging counterparties to the Fund or issuers of securities in which the Fund or the Underlying Fund invests.

Derivatives Risk. The Fund’s or Underlying Fund's use of derivatives may reduce the Fund’s or Underlying Fund's returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Counterparty risk for over-the-counter (“OTC”) derivatives is generally higher than that for derivatives traded on an exchange or through a clearing house. A risk of the Fund’s or Underlying Fund's use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund or Underlying Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund or Underlying Fund to sell or otherwise close a derivatives position could expose the Fund or Underlying Fund to losses and could make derivatives more difficult for the Fund or Underlying Fund to value accurately. The Fund or Underlying Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund or Underlying Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund or Underlying Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund or Underlying Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund or Underlying Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives.

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

Financials Sector Risk. Performance of companies in the financials sector may be adversely impacted by many factors, including, among others, changes in government regulations, economic conditions, and interest rates, credit rating downgrades, and decreased liquidity in credit markets. The extent to which the Fund may invest in a company that engages in securities-related activities or banking is limited by applicable law. The impact of changes in capital requirements and recent or future regulation of any individual financial company, or of the financials sector as a whole, cannot be predicted. In recent years, cyber-attacks and technology malfunctions and failures have become increasingly frequent in this sector and have caused significant losses to companies in this sector, which may negatively impact the Fund.

Geographic Risk. A natural disaster could occur in a geographic region in which the Fund or the Underlying Fund invests, which could affect the economy or particular business operations of companies in the specific geographic region, causing an adverse impact on the Fund's or the Underlying Fund's investments in the affected region.

Hedging Risk. The Fund seeks to mitigate the potential impact of interest rates on the performance of investment-grade corporate bonds by entering into positions in U.S. Treasury and other futures and interest rate swaps. The Fund’s Treasury and other futures positions and interest rate swaps are not intended to mitigate credit risk or other factors influencing the price of investment-grade corporate bonds, which may have a greater impact than interest rates. There is no guarantee that the Fund’s Treasury and other futures and interest rate swap positions will completely eliminate the interest rate risk of the long positions in investment-grade corporate bonds. In addition, when interest rates fall, long–only investment-grade bond investments will perform better than the Fund’s investments. In certain falling interest rate environments, the Fund’s hedging strategy could result in disproportionately larger losses in the Treasury and other futures and interest rate swap positions as compared to gains in the long investment-grade corporate bond positions attributable to interest rate changes. There is no guarantee the Fund will have positive returns, even in environments of sharply rising Treasury interest rates in which the Fund’s Treasury and other futures and interest rate swap positions might be expected to mitigate the effects of such rises. The Fund will incur expenses when entering into Treasury and other futures and interest rate swap positions.

Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices.

Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund or the Underlying Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, bonds in the Underlying Fund's index are substituted, or the Fund or the Underlying Fund otherwise needs to purchase additional bonds.

Industrials Sector Risk. Companies in the industrials sector may be adversely affected by changes in the supply of and demand for products and services, product obsolescence, claims for environmental damage or product liability and changes in general economic conditions, among other factors.

Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund or the Underlying Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. The Fund will take positions in Treasury and other futures and interest rate swaps. As a result, when interest rates decline, the Fund will underperform funds with long-only investments in the same investment-grade bonds as the Fund. There is no guarantee that the Fund or Underlying Fund will have positive performance even in environments of sharply rising interest rates. There is no guarantee that the Fund or Underlying Fund will be able to successfully mitigate interest rate risk.

Interest Rate Swap Risk. Interest rate swaps are subject to risks applicable to swaps generally, including the risk that a counterparty fails to meet its obligations and the risk that the Fund is not able to liquidate such swap in a timely manner or at all, which could result in losses to the Fund. Because the Fund will invest in swaps that are subject to central clearing, these swaps are subject to the risk that a central clearinghouse will go into bankruptcy or become non-operational, and sometimes involve increased transaction costs. Counterparties to OTC swaps are not subject to these risks. An interest rate swap may fail to perform as intended and may not offset adverse changes in interest rates fully or at all. An interest rate swap may also reduce the Fund’s gains due to favorable changes in interest rates and result in losses to the Fund. Counterparties to interest rate swaps are subject to manipulation in the marketplace of the reference benchmark rate, which may affect the utility of the swap as a hedge.

Investment in the Underlying Fund Risk. The Fund expects to invest a substantial portion of its assets in the Underlying Fund, so the Fund’s investment performance is likely to be directly related to the performance of the Underlying Fund. The Fund’s NAV will change with changes in the value of the Underlying Fund and other securities and instruments in which the Fund invests based on their market valuations. An investment in the Fund will entail more costs and expenses than a direct investment in the Underlying Fund.

As the Fund’s allocations to the Underlying Fund change from time to time, or to the extent that the expense ratio of the Underlying Fund changes, the weighted average operating expenses borne by the Fund may increase or decrease.

Through its investment in the Underlying Fund, the Fund is exposed to Management Risk, Market Risk, and Market Trading Risk, among other risks.

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

Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective.

Market Risk. The Fund and the Underlying Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns.

Market Trading Risk. The Fund and the Underlying Fund face numerous market trading risks, including the potential lack of an active market for their shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's or Underlying Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S AND THE UNDERLYING FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

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

Operational Risk. The Fund and the Underlying Fund are exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s or the Underlying Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund, the Underlying Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund or the Underlying Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential.

Privately-Issued Securities Risk. The Fund or the Underlying 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 (“1933 Act”). Privately-issued securities are securities that have not been registered under the 1933 Act and as a result may be subject to legal restrictions on resale. Privately-issued securities are generally not traded on established markets. As a result of the absence of a public trading market, privately issued securities may be deemed to be illiquid investments, may be more difficult to value than publicly traded securities and may be subject to wide fluctuations in value. Delay or difficulty in selling such securities may result in a loss to the Fund.

Risk of Investing in Russia. Investing in Russian securities involves significant risks, including legal, regulatory and economic risks that are specific to Russia. In addition, investing in Russian securities involves risks associated with the settlement of portfolio transactions and loss of the Fund’s ownership rights in its portfolio securities as a result of the system of share registration and custody in Russia. A number of jurisdictions, including the U.S., Canada and the European Union (the “EU”), have imposed economic sanctions on certain Russian individuals and Russian corporate entities. These and future sanctions, or even the threat of further sanctions, may adversely affect Russia’s economy and the Fund’s or the Underlying Fund's investments.

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

Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses.

Securities Lending Risk. The Fund or the Underlying Fund may engage in securities lending. Securities lending involves the risk that the Fund or the Underlying Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund or the Underlying Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund or Underlying Fund.

Tax Risk. The Underlying Fund invests in derivatives. The federal income tax treatment of a derivative may not be as favorable as a direct investment in an underlying asset. Derivatives may produce taxable income and taxable realized gain. Derivatives may adversely affect the timing, character and amount of income the Underlying Fund realizes from its investments. As a result, a larger portion of the Fund’s distributions may be treated as ordinary income rather than as capital gains. In addition, certain derivatives are subject to mark-to-market or straddle provisions of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). If such provisions are applicable, there could be an increase (or decrease) in the amount of taxable dividends paid by the Fund. Income from swaps is generally taxable. In addition, the tax treatment of certain derivatives, such as swaps, is unsettled and may be subject to future legislation, regulation or administrative pronouncements issued by the U.S. Internal Revenue Service (“IRS”).

<b>Performance Information</b>

The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.

<b>Year by Year Returns (Years Ended December 31)</b>

The best calendar quarter return during the periods shown above was 3.94% in the 4th quarter of 2016; the worst was -5.82% in the 4th quarter of 2018.

Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).

<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>

Average Annual Total Returns - iShares Interest Rate Hedged Long-Term Corporate Bond ETF		One Year	Since Fund Inception		Inception Date
iShares Interest Rate Hedged Long-Term Corporate Bond ETF		(3.35%)	2.47%		Jul. 22, 2015
iShares Interest Rate Hedged Long-Term Corporate Bond ETF | Return After Taxes on Distributions	[1]	(5.28%)	1.00%
iShares Interest Rate Hedged Long-Term Corporate Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares	[1]	(1.65%)	1.30%
Bloomberg Barclays U.S. Long Credit Interest Rate Swaps Hedged Index (Index returns do not reflect deductions for fees, expenses, or taxes)	[2]	(3.32%)	3.09%
ICE Q70A Custom Index (Index returns do not reflect deductions for fees, expenses, or taxes)	[2]	(3.82%)		[3]

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[2] The Bloomberg Barclays U.S. Long Credit Interest Rate Swaps Hedged Index is an unmanaged index that consists of the Bloomberg Barclays U.S. Long Credit Index plus interest rate swaps that intend to hedge the interest rate exposure of the Bloomberg Barclays U.S. Long Credit Index. On August 1, 2018, the Fund's performance benchmark changed from the Bloomberg Barclays U.S. Long Credit Interest Rate Swaps Hedged Index to the ICE Q70A Custom Index. The ICE Q70A Custom Index is an index that consists of the ICE BofAML 10+ Year US Corporate Index plus interest rate swaps that intend to hedge the interest rate exposure of the ICE BofAML 10+ Year US Corporate Index. The ICE Q70A Custom Index more accurately reflects the investment strategy of the Fund because the Underlying Fund tracks the ICE BofAML 10+ Year US Corporate Index as of August 1, 2018. Prior to August 1, 2018, the Underlying Fund tracked the Bloomberg Barclays U.S. Long Credit Index.

[3] The inception date of the ICE Q70A Custom Index was December 31, 2017. The average annual total return of this index for the period December 31, 2017 through December 31, 2018 was -3.82%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	iShares U.S. ETF Trust
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
iShares Interest Rate Hedged Long-Term Corporate Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	iSHARES<sup>®</sup> INTEREST RATE HEDGED LONG-TERM CORPORATE BOND ETF<br/>Ticker: IGBH                                 Stock Exchange: NYSE Arca
Objective [Heading]	rr_ObjectiveHeading	<b>Investment Objective</b>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The iShares Interest Rate Hedged Long-Term Corporate Bond ETF (the “Fund”) seeks to mitigate the interest rate risk of a portfolio composed of U.S. dollar-denominated investment-grade corporate bonds with remaining maturities greater than ten years.
Expense [Heading]	rr_ExpenseHeading	<b>Fees and Expenses</b>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares U.S. ETF Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”). BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fees so that the Fund’s total annual fund operating expenses after fee waiver is equal to the Acquired Fund Fees and Expenses attributable to the Fund’s investment in the iShares Long-Term Corporate Bond ETF (“IGLB” or the “Underlying Fund”), after taking into account any fee waivers by IGLB, plus 0.10% through February 28, 2022. The contractual waiver may be terminated prior to February 28, 2022 only upon written agreement of the Trust and BFA. You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<b>Annual Fund Operating Expenses<br/>(ongoing expenses that you pay each year as a<br/>percentage of the value of your investments) </b>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	February 28, 2022
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<b>Portfolio Turnover.</b>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund and the Underlying Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate for the Fund or the Underlying Fund may indicate higher transaction costs and may cause the Fund or the Underlying Fund to incur increased expenses. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example (except costs to the Underlying Fund included as part of Acquired Fund Fees and Expenses), affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 5% of the average value of its portfolio. To the extent the Underlying Fund incurs costs from high portfolio turnover, such costs may have a negative effect on the performance of the Fund.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	5.00%
Expense Exchange Traded Fund Commissions [Text]	rr_ExpenseExchangeTradedFundCommissions	You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:
Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]	rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees	Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the “Prospectus”).
Expense Example [Heading]	rr_ExpenseExampleHeading	<b>Example.</b>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Strategy [Heading]	rr_StrategyHeading	<b>Principal Investment Strategies</b>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund seeks to achieve its investment objective by investing, under normal circumstances, at least 80% of its net assets in U.S. dollar-denominated investment-grade corporate bonds with remaining maturities greater than ten years, in one or more underlying funds that principally invest in U.S. dollar-denominated investment-grade corporate bonds. The Fund intends to invest a substantial portion of its assets in one underlying fund, the Underlying Fund. The Fund attempts to mitigate the interest rate risk of the underlying securities and/or the Underlying Fund (as determined by BFA) primarily through the use of positions in both U.S. Treasury futures contracts and interest rate swaps (i.e., enter into a contract or contracts in which the Fund will make fixed-rate payments while receiving floating-rate payments based on a reference rate). The bonds in which the Fund and/or the Underlying Fund invest may include U.S. dollar-denominated investment-grade corporate bonds, including those of non-U.S. corporations, and generally have at least ten years until maturity at the time of investment. The Fund may also invest in other interest rate futures contracts, including but not limited to, Eurodollar and Federal Funds futures. The Fund’s futures and interest rate swap positions are not intended to mitigate credit risk or other factors influencing the price of investment-grade corporate bonds, which may have a greater impact than interest rates. Under normal circumstances, the Fund and the Underlying Fund will seek to maintain a weighted average maturity that is greater than ten years. Weighted average maturity is a U.S. dollar-weighted average of the remaining term to maturity of the underlying securities in the Underlying Fund's portfolio. The Fund is an actively managed exchange-traded fund (“ETF”) that does not seek to replicate the performance of a specified index. The Fund may also invest in other ETFs (including other iShares funds), U.S. government securities, options and swap contracts, short-term paper, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates. The Underlying Fund may invest up to 10% of its assets in certain futures, options and swap contracts, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates. The CFTC has adopted certain requirements that subject registered investment companies and their advisers to regulation by the CFTC if a registered investment company invests more than a prescribed level of its net asset value in CFTC-regulated futures, options and swaps, or if a registered investment company markets itself as providing investment exposure to such instruments. Due to the Fund’s potential use of CFTC-regulated futures, options and swaps above the prescribed levels, it is considered a “commodity pool” under the Commodity Exchange Act (“CEA”). The Fund may have a higher degree of portfolio turnover than funds that seek to replicate the performance of an index. 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).
Risk [Heading]	rr_RiskHeading	<b>Summary of Principal Risks</b>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below (either directly or through its investments in the Underlying Fund), any of which may adversely affect the Fund's net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objective. Unlike many ETFs, the Fund is not an index-based ETF. Asset Class Risk. Securities and other assets in the Fund's or the Underlying Fund's portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes. Assets Under Management (AUM) Risk. From time to time, an Authorized Participant (as defined in the Creations and Redemptions section of this Prospectus), a third-party investor, the Fund’s adviser or an affiliate of the Fund’s adviser, or a fund may invest in the Fund and hold its investment for a specific period of time to allow the Fund to achieve size or scale. There can be no assurance that any such entity would not redeem its investment or that the size of the Fund would be maintained at such levels, which could negatively impact the Fund. Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units (as defined in the Purchase and Sale of Fund Shares section of the Prospectus), Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes. Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund or the Underlying Fund may “call” or repay the security before its stated maturity, and the Fund or the Underlying Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund's or Underlying Fund's income, or in securities with greater risks or with other less favorable features. Commodity Regulatory Risk. The Fund is deemed a commodity pool and BFA is considered a “commodity pool operator” with respect to the Fund under the CEA. BFA is therefore subject to regulation by the SEC and the CFTC. BFA is also subject to regulation by National Futures Association (“NFA”). The regulatory requirements governing the use of commodity futures, options on commodity futures, certain swaps or certain other investments could change at any time. Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund's or the Underlying Fund's investments are concentrated in the securities of a particular issuer or issuers, in a particular country, group of countries, region, market, industry, group of industries, sector or asset class. Consumer Staples Sector Risk. The consumer staples sector may be affected by, among other things, marketing campaigns, changes in consumer demands, government regulations and changes in commodity prices. Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s or Underlying Fund's investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation. Cyber Security Risk. Failures or breaches of the electronic systems of the Fund or the Underlying Fund, the Fund's or the Underlying Fund's adviser, distributor, or other service providers (including the benchmark provider), market makers, Authorized Participants, hedging counterparties to the Fund or the issuers of securities in which the Fund or the Underlying Fund invests have the ability to cause disruptions and negatively impact the Fund’s business operations, potentially resulting in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cyber security plans and systems of the Fund’s service providers, market makers, Authorized Participants, hedging counterparties to the Fund or issuers of securities in which the Fund or the Underlying Fund invests. Derivatives Risk. The Fund’s or Underlying Fund's use of derivatives may reduce the Fund’s or Underlying Fund's returns or increase volatility. Volatility is defined as the characteristic of a security, a currency, an index or a market to fluctuate significantly in price within a short time period. Derivatives may also be subject to counterparty risk, which is the risk that the other party in the transaction will not fulfill its contractual obligation. Counterparty risk for over-the-counter (“OTC”) derivatives is generally higher than that for derivatives traded on an exchange or through a clearing house. A risk of the Fund’s or Underlying Fund's use of derivatives is that the fluctuations in their values may not correlate perfectly with the value of the underlying asset, the performance of the asset class to which the Fund or Underlying Fund seeks exposure or the performance of the overall markets. The possible lack of a liquid secondary market for derivatives and the resulting inability of the Fund or Underlying Fund to sell or otherwise close a derivatives position could expose the Fund or Underlying Fund to losses and could make derivatives more difficult for the Fund or Underlying Fund to value accurately. The Fund or Underlying Fund could also suffer losses related to its derivatives positions as a result of unanticipated market movements, or movements between the time of periodic reallocations of Fund or Underlying Fund assets, which losses are potentially unlimited. Certain derivatives may give rise to a form of leverage and may expose the Fund or Underlying Fund to greater risk and increase its costs. The impact of U.S. and global regulation of derivatives may make derivatives more costly, may limit the availability of derivatives, may delay or restrict the exercise by the Fund or Underlying Fund of termination rights or remedies upon a counterparty default under derivatives held by the Fund or Underlying Fund (which could result in losses), or may otherwise adversely affect the value or performance of derivatives. Extension Risk. During periods of rising interest rates, certain debt obligations may be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in the Fund’s or the Underlying Fund's income and potentially in the value of the Fund’s or an Underlying Fund's investments. Financials Sector Risk. Performance of companies in the financials sector may be adversely impacted by many factors, including, among others, changes in government regulations, economic conditions, and interest rates, credit rating downgrades, and decreased liquidity in credit markets. The extent to which the Fund may invest in a company that engages in securities-related activities or banking is limited by applicable law. The impact of changes in capital requirements and recent or future regulation of any individual financial company, or of the financials sector as a whole, cannot be predicted. In recent years, cyber-attacks and technology malfunctions and failures have become increasingly frequent in this sector and have caused significant losses to companies in this sector, which may negatively impact the Fund. Geographic Risk. A natural disaster could occur in a geographic region in which the Fund or the Underlying Fund invests, which could affect the economy or particular business operations of companies in the specific geographic region, causing an adverse impact on the Fund's or the Underlying Fund's investments in the affected region. Hedging Risk. The Fund seeks to mitigate the potential impact of interest rates on the performance of investment-grade corporate bonds by entering into positions in U.S. Treasury and other futures and interest rate swaps. The Fund’s Treasury and other futures positions and interest rate swaps are not intended to mitigate credit risk or other factors influencing the price of investment-grade corporate bonds, which may have a greater impact than interest rates. There is no guarantee that the Fund’s Treasury and other futures and interest rate swap positions will completely eliminate the interest rate risk of the long positions in investment-grade corporate bonds. In addition, when interest rates fall, long–only investment-grade bond investments will perform better than the Fund’s investments. In certain falling interest rate environments, the Fund’s hedging strategy could result in disproportionately larger losses in the Treasury and other futures and interest rate swap positions as compared to gains in the long investment-grade corporate bond positions attributable to interest rate changes. There is no guarantee the Fund will have positive returns, even in environments of sharply rising Treasury interest rates in which the Fund’s Treasury and other futures and interest rate swap positions might be expected to mitigate the effects of such rises. The Fund will incur expenses when entering into Treasury and other futures and interest rate swap positions. Illiquid Investments Risk. The Fund may invest up to an aggregate amount of 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. Income Risk. The Fund's income may decline when yields fall. This decline can occur because the Fund or the Underlying Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, bonds in the Underlying Fund's index are substituted, or the Fund or the Underlying Fund otherwise needs to purchase additional bonds. Industrials Sector Risk. Companies in the industrials sector may be adversely affected by changes in the supply of and demand for products and services, product obsolescence, claims for environmental damage or product liability and changes in general economic conditions, among other factors. Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund or the Underlying Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments. The historically low interest rate environment, together with recent modest rate increases, heightens the risks associated with rising interest rates. The Fund will take positions in Treasury and other futures and interest rate swaps. As a result, when interest rates decline, the Fund will underperform funds with long-only investments in the same investment-grade bonds as the Fund. There is no guarantee that the Fund or Underlying Fund will have positive performance even in environments of sharply rising interest rates. There is no guarantee that the Fund or Underlying Fund will be able to successfully mitigate interest rate risk. Interest Rate Swap Risk. Interest rate swaps are subject to risks applicable to swaps generally, including the risk that a counterparty fails to meet its obligations and the risk that the Fund is not able to liquidate such swap in a timely manner or at all, which could result in losses to the Fund. Because the Fund will invest in swaps that are subject to central clearing, these swaps are subject to the risk that a central clearinghouse will go into bankruptcy or become non-operational, and sometimes involve increased transaction costs. Counterparties to OTC swaps are not subject to these risks. An interest rate swap may fail to perform as intended and may not offset adverse changes in interest rates fully or at all. An interest rate swap may also reduce the Fund’s gains due to favorable changes in interest rates and result in losses to the Fund. Counterparties to interest rate swaps are subject to manipulation in the marketplace of the reference benchmark rate, which may affect the utility of the swap as a hedge. Investment in the Underlying Fund Risk. The Fund expects to invest a substantial portion of its assets in the Underlying Fund, so the Fund’s investment performance is likely to be directly related to the performance of the Underlying Fund. The Fund’s NAV will change with changes in the value of the Underlying Fund and other securities and instruments in which the Fund invests based on their market valuations. An investment in the Fund will entail more costs and expenses than a direct investment in the Underlying Fund. As the Fund’s allocations to the Underlying Fund change from time to time, or to the extent that the expense ratio of the Underlying Fund changes, the weighted average operating expenses borne by the Fund may increase or decrease. Through its investment in the Underlying Fund, the Fund is exposed to Management Risk, Market Risk, and Market Trading Risk, among other risks. Issuer Risk. The performance of the Fund depends on the performance of individual instruments to which the Fund or the Underlying Fund has exposure. Changes in the financial condition or credit rating of an issuer of those securities or counterparty on other instruments may cause the value of the securities or instruments to decline. Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and risk analyses applied by BFA will not produce the desired results, and that securities selected by BFA may underperform the market or any relevant benchmark. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective. Market Risk. The Fund and the Underlying Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Market Trading Risk. The Fund and the Underlying Fund face numerous market trading risks, including the potential lack of an active market for their shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund's or Underlying Fund's shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S AND THE UNDERLYING FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. Non-U.S. Issuers Risk. Securities issued by non-U.S. issuers carry different risks from securities issued by U.S. issuers. These risks include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or confiscatory taxation, adverse changes in investment or exchange control regulations, political instability, regulatory and economic differences, and potential restrictions on the flow of international capital. Operational Risk. The Fund and the Underlying Fund are exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s or the Underlying Fund's service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund, the Underlying Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks. Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund or the Underlying Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential. Privately-Issued Securities Risk. The Fund or the Underlying 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 (“1933 Act”). Privately-issued securities are securities that have not been registered under the 1933 Act and as a result may be subject to legal restrictions on resale. Privately-issued securities are generally not traded on established markets. As a result of the absence of a public trading market, privately issued securities may be deemed to be illiquid investments, may be more difficult to value than publicly traded securities and may be subject to wide fluctuations in value. Delay or difficulty in selling such securities may result in a loss to the Fund. Risk of Investing in Russia. Investing in Russian securities involves significant risks, including legal, regulatory and economic risks that are specific to Russia. In addition, investing in Russian securities involves risks associated with the settlement of portfolio transactions and loss of the Fund’s ownership rights in its portfolio securities as a result of the system of share registration and custody in Russia. A number of jurisdictions, including the U.S., Canada and the European Union (the “EU”), have imposed economic sanctions on certain Russian individuals and Russian corporate entities. These and future sanctions, or even the threat of further sanctions, may adversely affect Russia’s economy and the Fund’s or the Underlying Fund's investments. Risk of Investing in the U.S. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund or the Underlying Fund has exposure. Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses. Securities Lending Risk. The Fund or the Underlying Fund may engage in securities lending. Securities lending involves the risk that the Fund or the Underlying Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund or the Underlying Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund or Underlying Fund. Tax Risk. The Underlying Fund invests in derivatives. The federal income tax treatment of a derivative may not be as favorable as a direct investment in an underlying asset. Derivatives may produce taxable income and taxable realized gain. Derivatives may adversely affect the timing, character and amount of income the Underlying Fund realizes from its investments. As a result, a larger portion of the Fund’s distributions may be treated as ordinary income rather than as capital gains. In addition, certain derivatives are subject to mark-to-market or straddle provisions of the Internal Revenue Code of 1986, as amended (the “Internal Revenue Code”). If such provisions are applicable, there could be an increase (or decrease) in the amount of taxable dividends paid by the Fund. Income from swaps is generally taxable. In addition, the tax treatment of certain derivatives, such as swaps, is unsettled and may be subject to future legislation, regulation or administrative pronouncements issued by the U.S. Internal Revenue Service (“IRS”).
Risk Lose Money [Text]	rr_RiskLoseMoney	As with any investment, you could lose all or part of your investment in the Fund, and the Fund's performance could trail that of other investments.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<b>Performance Information</b>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	1-800-iShares (1-800-474-2737) (toll free)
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.iShares.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	<b>Year by Year Returns (Years Ended December 31)</b>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	The best calendar quarter return during the periods shown above was 3.94% in the 4th quarter of 2016; the worst was -5.82% in the 4th quarter of 2018. Updated performance information may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).
Performance Table Heading	rr_PerformanceTableHeading	<b>Average Annual Total Returns</b><br/><b>(for the periods ended December 31, 2018)</b>
Performance Table Market Index Changed	rr_PerformanceTableMarketIndexChanged	On August 1, 2018, the Fund's performance benchmark changed from the Bloomberg Barclays U.S. Long Credit Interest Rate Swaps Hedged Index to the ICE Q70A Custom Index.
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”).
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.
iShares Interest Rate Hedged Long-Term Corporate Bond ETF | iShares Interest Rate Hedged Long-Term Corporate Bond ETF
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.35%
Distribution and Service (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	none
Acquired Fund Fees and Expenses	rr_AcquiredFundFeesAndExpensesOverAssets	0.06%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.41%
Fee Waiver	rr_FeeWaiverOrReimbursementOverAssets	(0.25%)
Total Annual Fund Operating Expenses After Fee Waiver	rr_NetExpensesOverAssets	0.16%
1 Year	rr_ExpenseExampleYear01	$ 16
3 Years	rr_ExpenseExampleYear03	52
5 Years	rr_ExpenseExampleYear05	150
10 Years	rr_ExpenseExampleYear10	$ 440
2016	rr_AnnualReturn2016	6.98%
2017	rr_AnnualReturn2017	9.67%
2018	rr_AnnualReturn2018	(3.35%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	best
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2016
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	3.94%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	worst
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2018
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(5.82%)
One Year	rr_AverageAnnualReturnYear01	(3.35%)
Since Fund Inception	rr_AverageAnnualReturnSinceInception	2.47%
Inception Date	rr_AverageAnnualReturnInceptionDate	Jul. 22, 2015
iShares Interest Rate Hedged Long-Term Corporate Bond ETF | Return After Taxes on Distributions | iShares Interest Rate Hedged Long-Term Corporate Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(5.28%)	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	1.00%	[1]
iShares Interest Rate Hedged Long-Term Corporate Bond ETF | Return After Taxes on Distributions and Sale of Fund Shares | iShares Interest Rate Hedged Long-Term Corporate Bond ETF
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(1.65%)	[1]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	1.30%	[1]
iShares Interest Rate Hedged Long-Term Corporate Bond ETF | Bloomberg Barclays U.S. Long Credit Interest Rate Swaps Hedged Index (Index returns do not reflect deductions for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(3.32%)	[2]
Since Fund Inception	rr_AverageAnnualReturnSinceInception	3.09%	[2]
iShares Interest Rate Hedged Long-Term Corporate Bond ETF | ICE Q70A Custom Index (Index returns do not reflect deductions for fees, expenses, or taxes)
Risk/Return:	rr_RiskReturnAbstract
One Year	rr_AverageAnnualReturnYear01	(3.82%)	[2]
Since Fund Inception	rr_AverageAnnualReturnSinceInception		[2],[3]

[1] After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (“IRAs”). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.

[2] The Bloomberg Barclays U.S. Long Credit Interest Rate Swaps Hedged Index is an unmanaged index that consists of the Bloomberg Barclays U.S. Long Credit Index plus interest rate swaps that intend to hedge the interest rate exposure of the Bloomberg Barclays U.S. Long Credit Index. On August 1, 2018, the Fund's performance benchmark changed from the Bloomberg Barclays U.S. Long Credit Interest Rate Swaps Hedged Index to the ICE Q70A Custom Index. The ICE Q70A Custom Index is an index that consists of the ICE BofAML 10+ Year US Corporate Index plus interest rate swaps that intend to hedge the interest rate exposure of the ICE BofAML 10+ Year US Corporate Index. The ICE Q70A Custom Index more accurately reflects the investment strategy of the Fund because the Underlying Fund tracks the ICE BofAML 10+ Year US Corporate Index as of August 1, 2018. Prior to August 1, 2018, the Underlying Fund tracked the Bloomberg Barclays U.S. Long Credit Index.

[3] The inception date of the ICE Q70A Custom Index was December 31, 2017. The average annual total return of this index for the period December 31, 2017 through December 31, 2018 was -3.82%.

XML

Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	iShares U.S. ETF Trust
Prospectus Date	rr_ProspectusDate	Mar. 01, 2019
Document Creation Date	dei_DocumentCreationDate	Feb. 22, 2019