| Form N-CSR Cover | 6 Months Ended |
| Oct. 31, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| 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 | 6 Months Ended | |
| Oct. 31, 2024 USD ($) Holding | ||
| Shareholder Report [Line Items] | ||
| Document Type | N-CSRS | |
| 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 | |
| C000249928 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | iShares Long-Term U.S. Equity Active ETF | |
| Class Name | iShares Long-Term U.S. Equity Active ETF | |
| Trading Symbol | BELT | |
| Security Exchange Name | NASDAQ | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about iShares Long-Term U.S. Equity Active ETF (the “Fund”) (formerly known as BlackRock Long-Term U.S. Equity ETF) for the period of June 17, 2024 to October 31, 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) 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 Long-Term U.S. Equity Active ETF $ (a) 0.75 % (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 | $ 28 | [1] |
| Expense Ratio, Percent | 0.75% | [2] |
| Net Assets | $ 10,117,714 | |
| Holdings Count | Holding | 23 | |
| Investment Company Portfolio Turnover | 14% | |
| Additional Fund Statistics [Text Block] | Key Fund statistics Net Assets $ Number of Portfolio Holdings 23 Portfolio Turnover Rate 14 % | |
| Holdings [Text Block] | What did the Fund invest in? (as of October 31, 2024) Sector allocation Sector Percent of Total (a) Information Technology 32.8 % Health Care 16.6 % Communication Services 16.5 % Industrials 12.6 % Financials 11.9 % Consumer Discretionary 9.6 % Ten largest holdings Security Percent of Total (a) Microsoft Corp. 13.0 % Meta Platforms Inc., Class A 8.8 % Alphabet Inc., Class C 7.8 % Mastercard Inc., Class A 6.9 % Novo Nordisk A/S 5.8 % S&P Global Inc. 5.0 % Cadence Design Systems Inc. 5.0 % Trane Technologies PLC 4.6 % Ingersoll Rand Inc. 4.2 % Intuitive Surgical Inc. 4.2 % (a) Excludes money market funds. | |
| Largest Holdings [Text Block] | Ten largest holdings Security Percent of Total (a) Microsoft Corp. 13.0 % Meta Platforms Inc., Class A 8.8 % Alphabet Inc., Class C 7.8 % Mastercard Inc., Class A 6.9 % Novo Nordisk A/S 5.8 % S&P Global Inc. 5.0 % Cadence Design Systems Inc. 5.0 % Trane Technologies PLC 4.6 % Ingersoll Rand Inc. 4.2 % Intuitive Surgical Inc. 4.2 % (a) Excludes money market funds. | |
| C000249930 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | iShares Large Cap Growth Active ETF | |
| Class Name | iShares Large Cap Growth Active ETF | |
| Trading Symbol | BGRO | |
| Security Exchange Name | NASDAQ | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about iShares Large Cap Growth Active ETF (the “Fund”) (formerly known as BlackRock Large Cap Growth ETF) for the period of June 4, 2024 to October 31, 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) 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 Large Cap Growth Active ETF $ (a) 0.55 % (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 | $ 23 | [3] |
| Expense Ratio, Percent | 0.55% | [4] |
| Net Assets | $ 6,030,719 | |
| Holdings Count | Holding | 33 | |
| Investment Company Portfolio Turnover | 16% | |
| Additional Fund Statistics [Text Block] | Key Fund statistics Net Assets $ Number of Portfolio Holdings 33 Portfolio Turnover Rate 16 % | |
| Holdings [Text Block] | What did the Fund invest in? (as of October 31, 2024) Sector allocation Sector Percent of Total (a) Information Technology 47.4 % Consumer Discretionary 13.8 % Communication Services 13.5 % Health Care 8.4 % Financials 7.5 % Industrials 6.6 % Materials 1.4 % Real Estate 1.4 % Ten largest holdings Security Percent of Total (a) Nvidia Corp. 14.6 % Amazon.com Inc. 10.0 % Microsoft Corp. 9.8 % Apple Inc. 8.5 % Meta Platforms Inc., Class A 6.6 % Visa Inc., Class A 4.4 % Broadcom Inc. 4.3 % Cadence Design Systems Inc. 3.8 % Eli Lilly & Co. 3.5 % Alphabet Inc., Class A 3.3 % (a) Excludes money market funds. | |
| Largest Holdings [Text Block] | Ten largest holdings Security Percent of Total (a) Nvidia Corp. 14.6 % Amazon.com Inc. 10.0 % Microsoft Corp. 9.8 % Apple Inc. 8.5 % Meta Platforms Inc., Class A 6.6 % Visa Inc., Class A 4.4 % Broadcom Inc. 4.3 % Cadence Design Systems Inc. 3.8 % Eli Lilly & Co. 3.5 % Alphabet Inc., Class A 3.3 % (a) Excludes money market funds. | |
| C000251727 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | iShares A.I. Innovation and Tech Active ETF | |
| Class Name | iShares A.I. Innovation and Tech Active ETF | |
| Trading Symbol | BAI | |
| Security Exchange Name | NYSEArca | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about iShares A.I. Innovation and Tech Active ETF (the “Fund”) for the period of October 21, 2024 to October 31, 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) 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 A.I. Innovation and Tech Active ETF $ (a) 0.55 % (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 | $ 1 | [5] |
| Expense Ratio, Percent | 0.55% | [6] |
| Net Assets | $ 19,569,642 | |
| Holdings Count | Holding | 35 | |
| Investment Company Portfolio Turnover | 0% | |
| Additional Fund Statistics [Text Block] | Key Fund statistics Net Assets $ Number of Portfolio Holdings 35 Portfolio Turnover Rate 0 % | |
| Holdings [Text Block] | What did the Fund invest in? (as of October 31, 2024) Sector allocation Sector Percent of Total (a) Information Technology 70.6 % Communication Services 13.0 % Industrials 8.5 % Consumer Discretionary 5.9 % Utilities 2.0 % Ten largest holdings Security Percent of Total (a) Nvidia Corp. 9.0 % Meta Platforms Inc., Class A 7.1 % Microsoft Corp. 7.0 % Broadcom Inc. 4.9 % Taiwan Semiconductor Manufacturing Co. Ltd. 3.9 % Amazon.com Inc. 3.5 % Oracle Corp. 3.4 % Cadence Design Systems Inc. 3.3 % Astera Labs Inc. 3.3 % ServiceNow Inc. 3.1 % (a) Excludes money market funds. | |
| Largest Holdings [Text Block] | Ten largest holdings Security Percent of Total (a) Nvidia Corp. 9.0 % Meta Platforms Inc., Class A 7.1 % Microsoft Corp. 7.0 % Broadcom Inc. 4.9 % Taiwan Semiconductor Manufacturing Co. Ltd. 3.9 % Amazon.com Inc. 3.5 % Oracle Corp. 3.4 % Cadence Design Systems Inc. 3.3 % Astera Labs Inc. 3.3 % ServiceNow Inc. 3.1 % (a) Excludes money market funds. | |
| C000251728 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | iShares Technology Opportunities Active ETF | |
| Class Name | iShares Technology Opportunities Active ETF | |
| Trading Symbol | TEK | |
| Security Exchange Name | NYSEArca | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about iShares Technology Opportunities Active ETF (the “Fund”) for the period of October 21, 2024 to October 31, 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) 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 Technology Opportunities Active ETF $ (a) 0.75 % (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 | $ 2 | [7] |
| Expense Ratio, Percent | 0.75% | [8] |
| Net Assets | $ 12,609,138 | |
| Holdings Count | Holding | 58 | |
| Investment Company Portfolio Turnover | 0% | |
| Additional Fund Statistics [Text Block] | Key Fund statistics Net Assets $ Number of Portfolio Holdings 58 Portfolio Turnover Rate 0 % | |
| Holdings [Text Block] | What did the Fund invest in? (as of October 31, 2024) Sector allocation Sector Percent of Total (a) Information Technology 71.8 % Communication Services 11.5 % Industrials 6.3 % Consumer Discretionary 6.1 % Financials 3.7 % Utilities 0.6 % Ten largest holdings Security Percent of Total (a) Nvidia Corp. 14.0 % Microsoft Corp. 8.1 % Apple Inc. 7.2 % Meta Platforms Inc., Class A 5.6 % Broadcom Inc. 4.9 % Cadence Design Systems Inc. 2.8 % Taiwan Semiconductor Manufacturing Co. Ltd. 2.7 % ServiceNow Inc. 2.6 % Amazon.com Inc. 2.6 % Oracle Corp. 2.5 % (a) Excludes money market funds. | |
| Largest Holdings [Text Block] | Ten largest holdings Security Percent of Total (a) Nvidia Corp. 14.0 % Microsoft Corp. 8.1 % Apple Inc. 7.2 % Meta Platforms Inc., Class A 5.6 % Broadcom Inc. 4.9 % Cadence Design Systems Inc. 2.8 % Taiwan Semiconductor Manufacturing Co. Ltd. 2.7 % ServiceNow Inc. 2.6 % Amazon.com Inc. 2.6 % Oracle Corp. 2.5 % (a) Excludes money market funds. | |
| [1]The Fund commenced operations during the reporting period. Expenses for a full reporting period would be higher than the amount shown.[2]Annualized.[3]The Fund commenced operations during the reporting period. Expenses for a full reporting period would be higher than the amount shown.[4]Annualized.[5]The Fund commenced operations during the reporting period. Expenses for a full reporting period would be higher than the amount shown.[6]Annualized.[7]The Fund commenced operations during the reporting period. Expenses for a full reporting period would be higher than the amount shown.[8]Annualized. | ||
| Shareholder Report, Holdings (Details) | Oct. 31, 2024 | |
| C000249928 [Member] | Microsoft Corp [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 13% | [1] |
| C000249928 [Member] | Meta Platforms Inc Class A [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 8.80% | [1] |
| C000249928 [Member] | Alphabet Inc Class C [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 7.80% | [1] |
| C000249928 [Member] | Mastercard Inc Class A [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 6.90% | [1] |
| C000249928 [Member] | Novo Nordisk A S [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 5.80% | [1] |
| C000249928 [Member] | S And P Global Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 5% | [1] |
| C000249928 [Member] | Cadence Design Systems Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 5% | [1] |
| C000249928 [Member] | Trane Technologies PLC [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 4.60% | [1] |
| C000249928 [Member] | Ingersoll Rand Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 4.20% | [1] |
| C000249928 [Member] | Intuitive Surgical Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 4.20% | [1] |
| C000249928 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 32.80% | [1] |
| C000249928 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 16.60% | [1] |
| C000249928 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 16.50% | [1] |
| C000249928 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 12.60% | [1] |
| C000249928 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 11.90% | [1] |
| C000249928 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 9.60% | [1] |
| C000249930 [Member] | Microsoft Corp [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 9.80% | [2] |
| C000249930 [Member] | Meta Platforms Inc Class A [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 6.60% | [2] |
| C000249930 [Member] | Cadence Design Systems Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 3.80% | [2] |
| C000249930 [Member] | Nvidia Corp [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 14.60% | [2] |
| C000249930 [Member] | Amazon com Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 10% | [2] |
| C000249930 [Member] | Apple Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 8.50% | [2] |
| C000249930 [Member] | Visa Inc Class A [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 4.40% | [2] |
| C000249930 [Member] | Broadcom Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 4.30% | [2] |
| C000249930 [Member] | Eli Lilly And Co [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 3.50% | [2] |
| C000249930 [Member] | Alphabet Inc Class A [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 3.30% | [2] |
| C000249930 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 47.40% | [2] |
| C000249930 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 8.40% | [2] |
| C000249930 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 13.50% | [2] |
| C000249930 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 6.60% | [2] |
| C000249930 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 7.50% | [2] |
| C000249930 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 13.80% | [2] |
| C000249930 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 1.40% | [2] |
| C000249930 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 1.40% | [2] |
| C000251727 [Member] | Microsoft Corp [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 7% | [3] |
| C000251727 [Member] | Meta Platforms Inc Class A [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 7.10% | [3] |
| C000251727 [Member] | Cadence Design Systems Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 3.30% | [3] |
| C000251727 [Member] | Nvidia Corp [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 9% | [3] |
| C000251727 [Member] | Amazon com Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 3.50% | [3] |
| C000251727 [Member] | Broadcom Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 4.90% | [3] |
| C000251727 [Member] | Taiwan Semiconductor Manufacturing Co Ltd [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 3.90% | [3] |
| C000251727 [Member] | Oracle Corp [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 3.40% | [3] |
| C000251727 [Member] | Astera Labs Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 3.30% | [3] |
| C000251727 [Member] | ServiceNow Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 3.10% | [3] |
| C000251727 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 70.60% | [3] |
| C000251727 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 13% | [3] |
| C000251727 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 8.50% | [3] |
| C000251727 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 5.90% | [3] |
| C000251727 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 2% | [3] |
| C000251728 [Member] | Microsoft Corp [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 8.10% | [4] |
| C000251728 [Member] | Meta Platforms Inc Class A [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 5.60% | [4] |
| C000251728 [Member] | Cadence Design Systems Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 2.80% | [4] |
| C000251728 [Member] | Nvidia Corp [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 14% | [4] |
| C000251728 [Member] | Amazon com Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 2.60% | [4] |
| C000251728 [Member] | Apple Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 7.20% | [4] |
| C000251728 [Member] | Broadcom Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 4.90% | [4] |
| C000251728 [Member] | Taiwan Semiconductor Manufacturing Co Ltd [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 2.70% | [4] |
| C000251728 [Member] | Oracle Corp [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 2.50% | [4] |
| C000251728 [Member] | ServiceNow Inc [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 2.60% | [4] |
| C000251728 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 71.80% | [4] |
| C000251728 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 11.50% | [4] |
| C000251728 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 6.30% | [4] |
| C000251728 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 3.70% | [4] |
| C000251728 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 6.10% | [4] |
| C000251728 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Total Investments | 0.60% | [4] |
| [1]Excludes money market funds.[2]Excludes money market funds.[3]Excludes money market funds.[4]Excludes money market funds. | ||
