| Form N-CSR Cover | 6 Months Ended |
| Jun. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | BlackRock ETF Trust |
| Entity Central Index Key | 0001761055 |
| Document Period End Date | Jun. 30, 2024 |
| Shareholder Report | 6 Months Ended |
| Jun. 30, 2024 USD ($) Holding | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | BlackRock ETF Trust |
| Entity Central Index Key | 0001761055 |
| Document Period End Date | Jun. 30, 2024 |
| C000244680 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | BlackRock Advantage Large Cap Income ETF |
| Class Name | BlackRock Advantage Large Cap Income ETF |
| No Trading Symbol Flag | true |
| Security Exchange Name | CboeBZX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about BlackRock Advantage Large Cap Income ETF (the “Fund”) for the period of January 1, 2024 to June 30, 2024. |
| Shareholder Report Annual or Semi-Annual | semi-annual shareholder report |
| Additional Information [Text Block] | You can find additional information about the Fund at blackrock.com/fundreports |
| Additional Information Phone Number | (800) 441‑7762 |
| Additional Information Website | blackrock.com/fundreports |
| Expenses [Text Block] | What were the Fund costs for the last six months? (based on a hypothetical $10,000 investment) Fund name Costs of a $10,000 Costs paid as a percentage of a BlackRock Advantage Large Cap Income ETF $ 0.35 % |
| Expenses Paid, Amount | $ 19 |
| Expense Ratio, Percent | 0.35% |
| Performance Past Does Not Indicate Future [Text] | Past performance is not an indication of future results. |
| Average Annual Return [Table Text Block] | Average annual total returns 6-Month Since Fund NAV 14.30 % 25.87 % Fund Market 14.47 % 26.18 % S&P 500 ® 15.29 % 29.23 % |
| Performance Inception Date | Sep. 26, 2023 |
| 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 blackrock.com |
| Net Assets | $ 46,039,726 |
| Holdings Count | Holding | 131 |
| Investment Company Portfolio Turnover | 53% |
| Additional Fund Statistics [Text Block] | Key Fund statistics Net Assets $ % Number of Portfolio Holdings $ % Portfolio Turnover Rate $ % |
| Holdings [Text Block] | What did the Fund invest in? (as of June 30, 2024) Sector allocation Sector (a) Percent of Total (b) Information Technology 31.3 % Financials 13.3 % Health Care 13.1 % Communication Services 10.7 % Consumer Discretionary 10.6 % Industrials 8.4 % Consumer Staples 6.7 % Energy 2.9 % Utilities 1.3 % Materials 1.2 % Other (c) 0.5 % Ten largest holdings Security Percent of Total (b) Microsoft Corp. 8.2 % Apple Inc. 7.6 % NVIDIA Corp. 6.2 % Amazon.com, Inc. 4.9 % Alphabet, Inc., Class A 3.4 % Alphabet, Inc., Class C, NVS 2.0 % Eli Lilly & Co. 1.8 % Johnson & Johnson 1.8 % Mastercard, Inc., Class A 1.8 % Home Depot, Inc. (The) 1.7 % (a) For purposes of this report, sector sub-classifications may differ from those utilized for compliance purposes. (b) Excludes short-term securities, short investments and options, if any. (c) Ten largest sectors are presented. Additional sectors are found in Other. |
| Largest Holdings [Text Block] | Ten largest holdings Security Percent of Total (b) Microsoft Corp. 8.2 % Apple Inc. 7.6 % NVIDIA Corp. 6.2 % Amazon.com, Inc. 4.9 % Alphabet, Inc., Class A 3.4 % Alphabet, Inc., Class C, NVS 2.0 % Eli Lilly & Co. 1.8 % Johnson & Johnson 1.8 % Mastercard, Inc., Class A 1.8 % Home Depot, Inc. (The) 1.7 % |
| Shareholder Report, Line Graph (Details) | 6 Months Ended | 9 Months Ended |
| Jun. 30, 2024 | Jun. 30, 2024 | |
| C000244680 [Member] | ||
| Account Value [Line Items] | ||
| Line Graph and Table Measure Name | Fund NAV | |
| Average Annual Return, Percent | 14.30% | 25.87% |
| C000244680 [Member] | Without Sales Load [Member] | ||
| Account Value [Line Items] | ||
| Line Graph and Table Measure Name | Fund Market | |
| Average Annual Return, Percent | 14.47% | 26.18% |
| Standard & Poor's 500 Index [Member] | ||
| Account Value [Line Items] | ||
| Line Graph and Table Measure Name | S&P 500® Index | |
| Average Annual Return, Percent | 15.29% | 29.23% |
| Shareholder Report, Holdings (Details) - C000244680 [Member] | Jun. 30, 2024 | [1] |
| Microsoft Corp [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 8.20% | |
| Apple Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 7.60% | |
| NVIDIA Corp [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 6.20% | |
| Amazon com Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 4.90% | |
| Alphabet Inc Class A [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 3.40% | |
| Alphabet Inc Class C NVS [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 2% | |
| Eli Lilly And Co [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 1.80% | |
| Johnson And Johnson [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 1.80% | |
| Mastercard Inc Class A [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 1.80% | |
| Home Depot Inc The [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 1.70% | |
| Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 2.90% | [2] |
| Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 13.10% | [2] |
| Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 10.70% | [2] |
| Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 10.60% | [2] |
| Consumer Staples Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 6.70% | [2] |
| Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 8.40% | [2] |
| Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 31.30% | [2] |
| Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 1.20% | [2] |
| Unclassified Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 0.50% | [2],[3] |
| Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 1.30% | [2] |
| Financials [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 13.30% | [2] |
| [1]Excludes short-term securities, short investments and options, if any.[2]For purposes of this report, sector sub-classifications may differ from those utilized for compliance purposes.[3]Ten largest sectors are presented. Additional sectors are found in Other. | ||
