| Form N-CSR Cover | 12 Months Ended |
| Oct. 31, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | BlackRock ETF Trust |
| Entity Central Index Key | 0001761055 |
| 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 | BlackRock ETF Trust | |
| Entity Central Index Key | 0001761055 | |
| Entity Investment Company Type | N-1A | |
| Document Period End Date | Oct. 31, 2024 | |
| C000249919 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | iShares Enhanced Short-Term Bond Active ETF | |
| Class Name | iShares Enhanced Short-Term Bond Active ETF | |
| Trading Symbol | CSHP | |
| Security Exchange Name | NYSEArca | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about iShares Enhanced Short-Term Bond Active ETF (the “Fund”) (formerly known as BlackRock Enhanced Short-Term Bond ETF) for the period of July 17, 2024 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 | |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. | |
| Additional Information Phone Number | (800) 474‑2737 | |
| Additional Information Website | blackrock.com/fundreports | |
| Expenses [Text Block] | What were the Fund costs for the period ? (based on a hypothetical $10,000 investment) Fund name Costs of a $10,000 Costs paid as a percentage of a iShares Enhanced Short-Term Bond Active ETF $ (a) 0.20 % (b) (a) The Fund commenced operations during the reporting period. Expenses for a full reporting period would be higher than the amount shown. (b) Annualized. | |
| Expenses Paid, Amount | $ 6 | [1] |
| Expense Ratio, Percent | 0.20% | [2] |
| Material Change Date | Oct. 10, 2024 | |
| Net Assets | $ 27,640,242 | |
| Holdings Count | Holding | 8 | |
| Advisory Fees Paid, Amount | $ 7,437 | |
| Investment Company Portfolio Turnover | 0% | |
| Additional Fund Statistics [Text Block] | Key Fund statistics Net Assets $ Number of Portfolio Holdings 8 Net Investment Advisory Fees $ Portfolio Turnover Rate 0 % | |
| Holdings [Text Block] | What did the Fund invest in? (as of October 31, 2024) Portfolio composition Investment Type Percent of Total (a) U.S. Treasury Obligations 100.0 % Five largest holdings Security Percent of Total (a) U.S. Treasury Bill, 4.73%, 11/19/24 29.5 % U.S. Treasury Bill, 4.66%, 12/03/24 29.3 % U.S. Treasury Bill, 5.37%, 11/05/24 29.3 % U.S. Treasury Bill, 4.78%, 11/12/24 11.9 % (a) Excludes money market funds. | |
| Largest Holdings [Text Block] | Five largest holdings Security Percent of Total (a) U.S. Treasury Bill, 4.73%, 11/19/24 29.5 % U.S. Treasury Bill, 4.66%, 12/03/24 29.3 % U.S. Treasury Bill, 5.37%, 11/05/24 29.3 % U.S. Treasury Bill, 4.78%, 11/12/24 11.9 % (a) Excludes money market funds. | |
| Material Fund Change [Text Block] | Material Fund changes This is a summary of certain changes to the Fund since July 17, 2024. For more complete information, you may review the Fund’s next prospectus, which we expect to be available approximately 120 days after October 31, 2024 at blackrock.com/fundreports On July 30, 2024 the Fund's Board approved a proposal to change the name of the Fund from BlackRock Enhanced Short-Term Bond ETF to iShares Enhanced Short-Term Bond Active ETF. This change went effective on October 10, 2024. | |
| Material Fund Change Name [Text Block] | On July 30, 2024 the Fund's Board approved a proposal to change the name of the Fund from BlackRock Enhanced Short-Term Bond ETF to iShares Enhanced Short-Term Bond Active ETF. This change went effective on October 10, 2024. | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since July 17, 2024. For more complete information, you may review the Fund’s next prospectus, which we expect to be available approximately 120 days after October 31, 2024 at blackrock.com/fundreports | |
| Updated Prospectus Phone Number | (800) 474-2737 | |
| Updated Prospectus Web Address | blackrock.com/fundreports | |
| [1]The Fund commenced operations during the reporting period. Expenses for a full reporting period would be higher than the amount shown.[2]Annualized. | ||
| Shareholder Report, Holdings (Details) - C000249919 [Member] | Oct. 31, 2024 | [1] |
| U S Treasury Bill 4 73 11 19 24 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 29.50% | |
| U S Treasury Bill 4 66 12 03 24 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 29.30% | |
| U S Treasury Bill 5 37 11 05 24 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 29.30% | |
| U S Treasury Bill 4 78 11 12 24 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 11.90% | |
| U S Treasury Obligations [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 100% | |
| [1]Excludes money market funds. | ||
