| Form N-CSR Cover | 12 Months Ended |
| Oct. 31, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | iShares U.S. ETF Trust |
| Entity Central Index Key | 0001524513 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Oct. 31, 2024 |
| Shareholder Report | 12 Months Ended |
| Oct. 31, 2024 USD ($) Holding | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | iShares U.S. ETF Trust |
| Entity Central Index Key | 0001524513 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Oct. 31, 2024 |
| C000148680 | |
| Shareholder Report [Line Items] | |
| Fund Name | iShares Short Maturity Municipal Bond Active ETF |
| Trading Symbol | MEAR |
| Security Exchange Name | CboeBZX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about iShares Short Maturity Municipal Bond Active ETF (the “Fund”) (Formerly known as BlackRock Short Maturity Municipal Bond ETF) for the period of November 1, 2023 to October 31, 2024. |
| Shareholder Report Annual or Semi-Annual | Annual Shareholder Report |
| Additional Information [Text Block] | You can find additional information about the Fund at blackrock.com/fundreports |
| Additional Information Phone Number | 1-800-iShares (1-800-474-2737) |
| Additional Information Website | blackrock.com/fundreports |
| Expenses [Text Block] | What were the Fund costs for the last year? (based on a hypothetical $10,000 investment) Fund name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment iShares Short Maturity Municipal Bond Active ETF $26 0.25% |
| Expenses Paid, Amount | $ 26 |
| Expense Ratio, Percent | 0.25% |
| Factors Affecting Performance [Text Block] | How did the Fund perform last year? For the reporting period ended October 31, 2024, the Fund returned 4.30%. For the same period, the Bloomberg Municipal Bond Index returned 9.70% and the Bloomberg Municipal Bond: 1 Year (1-2) Index returned 4.42%. What contributed to performance? During the reporting period, a combination of moderating inflation levels and a softening labor market contributed to the U.S. Federal Reserve’s decision to loosen monetary policy with a 50-basis point target policy rate cut in September. Amid a volatile overall rate market, the investment adviser’s selective approach to the timing of duration extension trades was a positive contributor to the Fund’s performance. Variable rate demand note (“VRDN”) securities provided price protection from adverse market pricing changes because the securities traded at par while capturing increases in yields with daily or weekly rate adjustments and contributed to performance. A selective overweight to the 2-5year part of the yield curve also contributed to performance. From a credit perspective, A and BBB rated municipal bonds were additive. What detracted from performance? Detracting from the Fund’s performance during the reporting period were underweights to the tax-backed states, utilities and transportation sectors, and an underweight allocation to the one-two-year part of the yield curve. |
| Performance Past Does Not Indicate Future [Text] | Past performance is not an indication of future results. |
| Line Graph [Table Text Block] | Fund Bloomberg Municipal Bond Index Bloomberg Municipal Bond: 1 Year (1-2) Index Mar 15 $9,998 $10,050 $10,000 Apr 15 $9,994 $9,998 $10,000 May 15 $9,972 $9,970 $10,000 Jun 15 $9,978 $9,961 $10,000 Jul 15 $9,999 $10,033 $10,013 Aug 15 $10,017 $10,053 $10,030 Sep 15 $10,034 $10,125 $10,042 Oct 15 $10,048 $10,166 $10,052 Nov 15 $10,034 $10,206 $10,040 Dec 15 $10,036 $10,278 $10,038 Jan 16 $10,062 $10,400 $10,069 Feb 16 $10,084 $10,417 $10,085 Mar 16 $10,076 $10,450 $10,071 Apr 16 $10,087 $10,527 $10,082 May 16 $10,092 $10,555 $10,087 Jun 16 $10,111 $10,723 $10,104 Jul 16 $10,125 $10,730 $10,122 Aug 16 $10,126 $10,744 $10,107 Sep 16 $10,111 $10,690 $10,085 Oct 16 $10,118 $10,578 $10,092 Nov 16 $10,086 $10,184 $10,049 Dec 16 $10,095 $10,303 $10,068 Jan 17 $10,119 $10,371 $10,105 Feb 17 $10,145 $10,443 $10,138 Mar 17 $10,149 $10,466 $10,138 Apr 17 $10,161 $10,542 $10,154 May 17 $10,177 $10,709 $10,173 Jun 17 $10,173 $10,671 $10,165 Jul 17 $10,192 $10,757 $10,189 Aug 17 $10,215 $10,839 $10,212 Sep 17 $10,210 $10,784 $10,200 Oct 17 $10,213 $10,810 $10,201 Nov 17 $10,183 $10,752 $10,155 Dec 17 $10,193 $10,865 $10,161 Jan 18 $10,209 $10,737 $10,190 Feb 18 $10,220 $10,705 $10,207 Mar 18 $10,223 $10,744 $10,200 Apr 18 $10,223 $10,706 $10,190 May 18 $10,247 $10,828 $10,224 Jun 18 $10,269 $10,838 $10,260 Jul 18 $10,293 $10,864 $10,281 Aug 18 $10,300 $10,892 $10,278 Sep 18 $10,299 $10,821 $10,258 Oct 18 $10,310 $10,755 $10,267 Nov 18 $10,331 $10,874 $10,299 Dec 18 $10,354 $11,004 $10,338 Jan 19 $10,377 $11,087 $10,370 Feb 19 $10,396 $11,146 $10,394 Mar 19 $10,416 $11,323 $10,422 Apr 19 $10,428 $11,365 $10,430 May 19 $10,456 $11,522 $10,469 Jun 19 $10,476 $11,564 $10,501 Jul 19 $10,504 $11,658 $10,536 Aug 19 $10,519 $11,842 $10,550 Sep 19 $10,513 $11,747 $10,528 Oct 19 $10,533 $11,768 $10,559 Nov 19 $10,546 $11,797 $10,577 Dec 19 $10,564 $11,833 $10,592 Jan 20 $10,585 $12,046 $10,630 Feb 20 $10,605 $12,201 $10,651 Mar 20 $10,531 $11,759 $10,598 Apr 20 $10,549 $11,611 $10,623 May 20 $10,598 $11,980 $10,728 Jun 20 $10,625 $12,079 $10,728 Jul 20 $10,649 $12,282 $10,755 Aug 20 $10,657 $12,225 $10,756 Sep 20 $10,670 $12,227 $10,764 Oct 20 $10,668 $12,191 $10,756 Nov 20 $10,677 $12,375 $10,769 Dec 20 $10,681 $12,450 $10,779 Jan 21 $10,690 $12,529 $10,797 Feb 21 $10,687 $12,330 $10,793 Mar 21 $10,693 $12,406 $10,801 Apr 21 $10,697 $12,510 $10,808 May 21 $10,696 $12,548 $10,813 Jun 21 $10,695 $12,582 $10,812 Jul 21 $10,703 $12,686 $10,826 Aug 21 $10,701 $12,640 $10,823 Sep 21 $10,694 $12,549 $10,812 Oct 21 $10,689 $12,512 $10,810 Nov 21 $10,689 $12,618 $10,813 Dec 21 $10,688 $12,639 $10,812 Jan 22 $10,651 $12,293 $10,740 Feb 22 $10,646 $12,249 $10,726 Mar 22 $10,616 $11,852 $10,637 Apr 22 $10,594 $11,524 $10,594 May 22 $10,621 $11,695 $10,675 Jun 22 $10,627 $11,504 $10,678 Jul 22 $10,650 $11,808 $10,736 Aug 22 $10,636 $11,549 $10,650 Sep 22 $10,622 $11,105 $10,558 Oct 22 $10,634 $11,013 $10,572 Nov 22 $10,691 $11,528 $10,694 Dec 22 $10,704 $11,561 $10,688 Jan 23 $10,751 $11,893 $10,778 Feb 23 $10,749 $11,624 $10,687 Mar 23 $10,802 $11,882 $10,802 Apr 23 $10,812 $11,855 $10,770 May 23 $10,834 $11,752 $10,758 Jun 23 $10,889 $11,870 $10,810 Jul 23 $10,923 $11,917 $10,833 Aug 23 $10,948 $11,746 $10,844 Sep 23 $10,953 $11,401 $10,800 Oct 23 $10,988 $11,304 $10,831 Nov 23 $11,075 $12,022 $10,947 Dec 23 $11,128 $12,301 $10,998 Jan 24 $11,151 $12,239 $11,005 Feb 24 $11,181 $12,254 $11,026 Mar 24 $11,209 $12,254 $11,035 Apr 24 $11,235 $12,102 $11,050 May 24 $11,275 $12,067 $11,076 Jun 24 $11,321 $12,252 $11,139 Jul 24 $11,365 $12,363 $11,212 Aug 24 $11,423 $12,461 $11,286 Sep 24 $11,461 $12,584 $11,321 Oct 24 $11,460 $12,400 $11,293 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Years Since Fund Inception Fund NAV ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 4.30 % 1.70 % 1.42 % Bloomberg Municipal Bond Index ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 9.70 1.05 2.25 Bloomberg Municipal Bond: 1 Year (1-2) Index ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 4.42 1.38 1.28 |
| Performance Inception Date | Mar. 03, 2015 |
| No Deduction of Taxes [Text Block] | Performance results do not reflect the deduction of taxes that a shareholder would pay on fund distributions or on the redemption or sale of fund shares. |
| Updated Performance Information Location [Text Block] | Visit iShares.com |
| AssetsNet | $ 682,282,883 |
| Holdings Count | Holding | 220 |
| Advisory Fees Paid, Amount | $ 1,630,132 |
| InvestmentCompanyPortfolioTurnover | 91% |
| Additional Fund Statistics [Text Block] | Key Fund statistics Net Assets ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ $682,282,883 Number of Portfolio Holdings ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 220 Net Investment Advisory Fees ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ $1,630,132 Portfolio Turnover Rate ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 91% |
| Holdings [Text Block] | Credit quality allocation Ten largest states S&P Credit Rating Footnote Reference Percent of Total Investments Footnote Reference AAA ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 3.3 % AA+ ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 26.5 AA ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 7.2 AA- ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 5.1 A+ ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 4.3 A ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 3.6 A- ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 13.6 BBB+ ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 4.4 BBB ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 0.5 Not Rated ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 31.5 State Percent of TotaI Investments Footnote Reference Texas ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 11.5 % Iowa ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 8.9 New York ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 7.7 Tennessee ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 7.2 New Jersey ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 5.8 Alabama ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 5.7 Louisiana ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 5.3 Illinois ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 3.9 Wisconsin ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 3.9 Kentucky ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 3.7 Footnote Description Footnote * Credit quality ratings shown reflect the ratings assigned by S&P Global Ratings, a widely used independent, nationally recognized statistical rating organization. S&P credit ratings are opinions of the credit quality of individual obligations or of an issuer’s general creditworthiness. Investment grade ratings are credit ratings of BBB or higher. Below investment grade ratings are credit ratings of BB or lower. Unrated investments do not necessarily indicate low credit quality. Credit quality ratings are subject to change. Footnote (a) Excludes money market funds. |
| Shareholder Report, Line Graph (Details) - USD ($) | 5 Months Ended | 12 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mar. 31, 2015 | Oct. 31, 2024 | Sep. 30, 2024 | Aug. 31, 2024 | Jul. 31, 2024 | Jun. 30, 2024 | May 31, 2024 | Apr. 30, 2024 | Mar. 31, 2024 | Feb. 29, 2024 | Jan. 31, 2024 | Dec. 31, 2023 | Nov. 30, 2023 | Oct. 31, 2023 | Sep. 30, 2023 | Aug. 31, 2023 | Jul. 31, 2023 | Jun. 30, 2023 | May 31, 2023 | Apr. 30, 2023 | Mar. 31, 2023 | Feb. 28, 2023 | Jan. 31, 2023 | Dec. 31, 2022 | Nov. 30, 2022 | Oct. 31, 2022 | Sep. 30, 2022 | Aug. 31, 2022 | Jul. 31, 2022 | Jun. 30, 2022 | May 31, 2022 | Apr. 30, 2022 | Mar. 31, 2022 | Feb. 28, 2022 | Jan. 31, 2022 | Dec. 31, 2021 | Nov. 30, 2021 | Oct. 31, 2021 | Sep. 30, 2021 | Aug. 31, 2021 | Jul. 31, 2021 | Jun. 30, 2021 | May 31, 2021 | Apr. 30, 2021 | Mar. 31, 2021 | Feb. 28, 2021 | Jan. 31, 2021 | Dec. 31, 2020 | Nov. 30, 2020 | Oct. 31, 2020 | Sep. 30, 2020 | Aug. 31, 2020 | Jul. 31, 2020 | Jun. 30, 2020 | May 31, 2020 | Apr. 30, 2020 | Mar. 31, 2020 | Feb. 29, 2020 | Jan. 31, 2020 | Dec. 31, 2019 | Nov. 30, 2019 | Oct. 31, 2019 | Sep. 30, 2019 | Aug. 31, 2019 | Jul. 31, 2019 | Jun. 30, 2019 | May 31, 2019 | Apr. 30, 2019 | Mar. 31, 2019 | Feb. 28, 2019 | Jan. 31, 2019 | Dec. 31, 2018 | Nov. 30, 2018 | Oct. 31, 2018 | Sep. 30, 2018 | Aug. 31, 2018 | Jul. 31, 2018 | Jun. 30, 2018 | May 31, 2018 | Apr. 30, 2018 | Mar. 31, 2018 | Feb. 28, 2018 | Jan. 31, 2018 | Dec. 31, 2017 | Nov. 30, 2017 | Oct. 31, 2017 | Sep. 30, 2017 | Aug. 31, 2017 | Jul. 31, 2017 | Jun. 30, 2017 | May 31, 2017 | Apr. 30, 2017 | Mar. 31, 2017 | Feb. 28, 2017 | Jan. 31, 2017 | Dec. 31, 2016 | Nov. 30, 2016 | Oct. 31, 2016 | Sep. 30, 2016 | Aug. 31, 2016 | Jul. 31, 2016 | Jun. 30, 2016 | May 31, 2016 | Apr. 30, 2016 | Mar. 31, 2016 | Feb. 29, 2016 | Jan. 31, 2016 | Dec. 31, 2015 | Nov. 30, 2015 | Oct. 31, 2015 | Sep. 30, 2015 | Aug. 31, 2015 | Jul. 31, 2015 | Jun. 30, 2015 | May 31, 2015 | Apr. 30, 2015 | |
| C000148680 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | Fund | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 9,998 | $ 11,460 | $ 11,461 | $ 11,423 | $ 11,365 | $ 11,321 | $ 11,275 | $ 11,235 | $ 11,209 | $ 11,181 | $ 11,151 | $ 11,128 | $ 11,075 | $ 10,988 | $ 10,953 | $ 10,948 | $ 10,923 | $ 10,889 | $ 10,834 | $ 10,812 | $ 10,802 | $ 10,749 | $ 10,751 | $ 10,704 | $ 10,691 | $ 10,634 | $ 10,622 | $ 10,636 | $ 10,650 | $ 10,627 | $ 10,621 | $ 10,594 | $ 10,616 | $ 10,646 | $ 10,651 | $ 10,688 | $ 10,689 | $ 10,689 | $ 10,694 | $ 10,701 | $ 10,703 | $ 10,695 | $ 10,696 | $ 10,697 | $ 10,693 | $ 10,687 | $ 10,690 | $ 10,681 | $ 10,677 | $ 10,668 | $ 10,670 | $ 10,657 | $ 10,649 | $ 10,625 | $ 10,598 | $ 10,549 | $ 10,531 | $ 10,605 | $ 10,585 | $ 10,564 | $ 10,546 | $ 10,533 | $ 10,513 | $ 10,519 | $ 10,504 | $ 10,476 | $ 10,456 | $ 10,428 | $ 10,416 | $ 10,396 | $ 10,377 | $ 10,354 | $ 10,331 | $ 10,310 | $ 10,299 | $ 10,300 | $ 10,293 | $ 10,269 | $ 10,247 | $ 10,223 | $ 10,223 | $ 10,220 | $ 10,209 | $ 10,193 | $ 10,183 | $ 10,213 | $ 10,210 | $ 10,215 | $ 10,192 | $ 10,173 | $ 10,177 | $ 10,161 | $ 10,149 | $ 10,145 | $ 10,119 | $ 10,095 | $ 10,086 | $ 10,118 | $ 10,111 | $ 10,126 | $ 10,125 | $ 10,111 | $ 10,092 | $ 10,087 | $ 10,076 | $ 10,084 | $ 10,062 | $ 10,036 | $ 10,034 | $ 10,048 | $ 10,034 | $ 10,017 | $ 9,999 | $ 9,978 | $ 9,972 | $ 9,994 |
| FR TSR Growth 10k - Benchmark 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 10,050 | 12,400 | 12,584 | 12,461 | 12,363 | 12,252 | 12,067 | 12,102 | 12,254 | 12,254 | 12,239 | 12,301 | 12,022 | 11,304 | 11,401 | 11,746 | 11,917 | 11,870 | 11,752 | 11,855 | 11,882 | 11,624 | 11,893 | 11,561 | 11,528 | 11,013 | 11,105 | 11,549 | 11,808 | 11,504 | 11,695 | 11,524 | 11,852 | 12,249 | 12,293 | 12,639 | 12,618 | 12,512 | 12,549 | 12,640 | 12,686 | 12,582 | 12,548 | 12,510 | 12,406 | 12,330 | 12,529 | 12,450 | 12,375 | 12,191 | 12,227 | 12,225 | 12,282 | 12,079 | 11,980 | 11,611 | 11,759 | 12,201 | 12,046 | 11,833 | 11,797 | 11,768 | 11,747 | 11,842 | 11,658 | 11,564 | 11,522 | 11,365 | 11,323 | 11,146 | 11,087 | 11,004 | 10,874 | 10,755 | 10,821 | 10,892 | 10,864 | 10,838 | 10,828 | 10,706 | 10,744 | 10,705 | 10,737 | 10,865 | 10,752 | 10,810 | 10,784 | 10,839 | 10,757 | 10,671 | 10,709 | 10,542 | 10,466 | 10,443 | 10,371 | 10,303 | 10,184 | 10,578 | 10,690 | 10,744 | 10,730 | 10,723 | 10,555 | 10,527 | 10,450 | 10,417 | 10,400 | 10,278 | 10,206 | 10,166 | 10,125 | 10,053 | 10,033 | 9,961 | 9,970 | 9,998 |
| iShares Short Maturity Municipal Bond Active ETF | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond Index | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| FR TSR Growth 10k - Benchmark 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value | $ 10,000 | $ 11,293 | $ 11,321 | $ 11,286 | $ 11,212 | $ 11,139 | $ 11,076 | $ 11,050 | $ 11,035 | $ 11,026 | $ 11,005 | $ 10,998 | $ 10,947 | $ 10,831 | $ 10,800 | $ 10,844 | $ 10,833 | $ 10,810 | $ 10,758 | $ 10,770 | $ 10,802 | $ 10,687 | $ 10,778 | $ 10,688 | $ 10,694 | $ 10,572 | $ 10,558 | $ 10,650 | $ 10,736 | $ 10,678 | $ 10,675 | $ 10,594 | $ 10,637 | $ 10,726 | $ 10,740 | $ 10,812 | $ 10,813 | $ 10,810 | $ 10,812 | $ 10,823 | $ 10,826 | $ 10,812 | $ 10,813 | $ 10,808 | $ 10,801 | $ 10,793 | $ 10,797 | $ 10,779 | $ 10,769 | $ 10,756 | $ 10,764 | $ 10,756 | $ 10,755 | $ 10,728 | $ 10,728 | $ 10,623 | $ 10,598 | $ 10,651 | $ 10,630 | $ 10,592 | $ 10,577 | $ 10,559 | $ 10,528 | $ 10,550 | $ 10,536 | $ 10,501 | $ 10,469 | $ 10,430 | $ 10,422 | $ 10,394 | $ 10,370 | $ 10,338 | $ 10,299 | $ 10,267 | $ 10,258 | $ 10,278 | $ 10,281 | $ 10,260 | $ 10,224 | $ 10,190 | $ 10,200 | $ 10,207 | $ 10,190 | $ 10,161 | $ 10,155 | $ 10,201 | $ 10,200 | $ 10,212 | $ 10,189 | $ 10,165 | $ 10,173 | $ 10,154 | $ 10,138 | $ 10,138 | $ 10,105 | $ 10,068 | $ 10,049 | $ 10,092 | $ 10,085 | $ 10,107 | $ 10,122 | $ 10,104 | $ 10,087 | $ 10,082 | $ 10,071 | $ 10,085 | $ 10,069 | $ 10,038 | $ 10,040 | $ 10,052 | $ 10,042 | $ 10,030 | $ 10,013 | $ 10,000 | $ 10,000 | $ 10,000 |
| FR Notes - Benchmark total return 1 year w/o sales charge - 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Account Value [Line Items] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond: 1 Year (1-2) Index |
| Shareholder Report, Average Annual Return (Details) | 5 Months Ended | 12 Months Ended | 60 Months Ended | 120 Months Ended |
| Mar. 31, 2015 | Oct. 31, 2024 | Oct. 31, 2024 | Oct. 31, 2024 | |
| C000148680 | ||||
| Average Annual Return [Line Items] | ||||
| Line Graph and Table Measure Name | Fund | |||
| Without Sales Load [Member] | C000148680 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 4.30% | 1.70% | 1.42% | |
| FR Notes - Benchmark total return 1 year w/o sales charge | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 9.70% | |||
| FR Notes - Benchmark total return 5 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 1.05% | |||
| FR Notes - Benchmark total return 10 year | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 2.25% | |||
| iShares Short Maturity Municipal Bond Active ETF | ||||
| Average Annual Return [Line Items] | ||||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond Index | |||
| FR Notes - Benchmark total return 1 year w/o sales charge - 2 | ||||
| Average Annual Return [Line Items] | ||||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond: 1 Year (1-2) Index | |||
| Average Annual Return, Percent | 4.42% | |||
| FR Notes - Benchmark total return 5 year - 2 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 1.38% | |||
| FR Notes - Benchmark total return 10 year - 2 | ||||
| Average Annual Return [Line Items] | ||||
| Average Annual Return, Percent | 1.28% |
| Shareholder Report, Holdings (Details) - C000148680 | Oct. 31, 2024 |
| Texas | |
| Holdings [Line Items] | |
| Percent of Total Investments | 11.50% |
| Iowa | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.90% |
| New York | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.70% |
| Tennessee | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.20% |
| New Jersey | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.80% |
| Alabama | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.70% |
| Louisiana | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.30% |
| Illinois | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.90% |
| Wisconsin | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.90% |
| Kentucky | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.70% |
| AAA | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.30% |
| AA+ | |
| Holdings [Line Items] | |
| Percent of Total Investments | 26.50% |
| AA | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.20% |
| AA- | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.10% |
| A+ | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4.30% |
| A | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.60% |
| A- | |
| Holdings [Line Items] | |
| Percent of Total Investments | 13.60% |
| BBB+ | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4.40% |
| BBB | |
| Holdings [Line Items] | |
| Percent of Total Investments | 0.50% |
| Not Rated | |
| Holdings [Line Items] | |
| Percent of Total Investments | 31.50% |
