| Form N-CSR Cover | 12 Months Ended |
| Aug. 31, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | Putnam ETF Trust |
| Entity Central Index Key | 0001845809 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Aug. 31, 2024 |
| Shareholder Report | 12 Months Ended | |
| Aug. 31, 2024 USD ($) $ / shares | ||
| Shareholder Report [Line Items] | ||
| Document Type | N-CSR | |
| Amendment Flag | false | |
| Registrant Name | Putnam ETF Trust | |
| Entity Central Index Key | 0001845809 | |
| Entity Investment Company Type | N-1A | |
| Document Period End Date | Aug. 31, 2024 | |
| Putnam Sustainable Leaders ETF | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Putnam Sustainable Leaders ETF | |
| Class Name | Putnam Sustainable Leaders ETF | |
| Trading Symbol | PLDR | |
| Security Exchange Name | NYSEArca | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about Putnam Sustainable Leaders ETF for the period September 1, 2023, to August 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://www.franklintempleton.com/regulatory-fund-documents . You can also request this information by contacting us at (800) DIAL BEN/342-5236 . | |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. | |
| Additional Information Phone Number | (800) DIAL BEN/342-5236 | |
| Additional Information Website | https://www.franklintempleton.com/regulatory-fund-documents | |
| 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 * Putnam Sustainable Leaders ETF $68 0.59% | [1] |
| Expenses Paid, Amount | $ 68 | |
| Expense Ratio, Percent | 0.59% | |
| Factors Affecting Performance [Text Block] | HOW DID THE FUND PERFORM LAST YEAR AND WHAT AFFECTED ITS PERFORMANCE? For the twelve months ended August 31, 2024, Putnam Sustainable Leaders ETF returned 32.00% based on NAV and 31.91% based on market price. The Fund compares its performance to the S&P 500 Index, which returned 27.14% for the same period. PERFORMANCE HIGHLIGHTS Top contributors to performance: ↑ Overweight position relative to the benchmark in Constellation Energy, a power company. ↑ Overweight position in NVIDIA, a leading designer of graphic processing units. ↑ Decision to not own Tesla, a stock in the Fund’s benchmark, had a positive impact on relative performance. Top detractors from performance: ↓ Decision to not own Meta Platforms and Broadcom, stocks in the Fund’s benchmark, detracted from relative performance. ↓ Overweight position in Fortive, an industrial technology company. ↓ Overweight position in software company Adobe. | |
| Performance Past Does Not Indicate Future [Text] | The Fund’s past performance is not necessarily an indication of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | ||
| Average Annual Return [Table Text Block] | AVERAGE ANNUAL TOTAL RETURNS (%) Period Ended August 31, 2024 1 Year Since Inception (5/25/2021) Putnam Sustainable Leaders ETF (NAV) 32.00 9.50 Putnam Sustainable Leaders ETF (Market Price) 31.91 9.50 Russell 3000 Index 26.14 9.74 S&P 500 Index 27.14 11.29 | |
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares. | |
| Updated Performance Information Location [Text Block] | For current month-end performance, please call Franklin Templeton at (800) DIAL BEN/342-5236 or visit https://www.franklintempleton.com/investments/options/exchange-traded-funds . Important data provider notices and terms available at www.franklintempletondatasources.com. | |
| Net Assets | $ 577,519,297 | |
| Holdings Count | $ / shares | 59 | [2] |
| Advisory Fees Paid, Amount | $ 2,751,626 | |
| Investment Company Portfolio Turnover | 32% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of August 31, 2024) Total Net Assets $577,519,297 Total Number of Portfolio Holdings * 59 Total Management Fee Paid (based on a unitary fee) $2,751,626 Portfolio Turnover Rate 32% | [2] |
| Holdings [Text Block] | [3] | |
| Material Fund Change [Text Block] | HOW HAS THE FUND CHANGED? Effective December 30, 2023, the following disclosure was added to the Fund’s prospectus: “We may also invest in non-U.S. companies.” On May 31, 2023, Franklin Resources, Inc. (“Franklin Resources”) and Great-West Lifeco Inc., the parent company of Putnam U.S. Holdings I, LLC (“Putnam Holdings”), announced that they had entered into a definitive agreement for a subsidiary of Franklin Resources to acquire Putnam Holdings in a stock and cash transaction (the “Transaction”). The Transaction was completed on January 1, 2024. As part of the Transaction, your Fund’s investment advisor, Putnam Investment Management, LLC (“Putnam Management”), a wholly-owned subsidiary of Putnam Holdings, and your Fund’s sub-advisor, Putnam Investments Limited (“PIL”), an indirect, wholly-owned subsidiary of Putnam Holdings, became indirect, wholly-owned subsidiaries of Franklin Resources. In connection with the Transaction, shareholders of your Fund approved a new management contract with Putnam Management and a new sub-advisory contract with PIL. The new contracts are identical to the previous contracts, except for the effective dates, initial terms, updates to fund names as necessary to reflect previous name changes, and certain non-substantive changes. Effective July 15, 2024, Franklin Advisers, Inc. (“Franklin Advisers”) was retained as a sub-adviser by Putnam Management for the Fund pursuant to a new subadvisory agreement between Franklin Advisers and Putnam Management. Both Putnam Management and Franklin Advisers are wholly-owned subsidiaries of Franklin Resources. Putnam Management will continue to serve as the Fund’s investment advisor, and PIL will continue to serve as sub-advisor to the Fund. This is a summary of certain changes to the Fund since September 1, 2023. For more complete information, you may review the Fund’s current prospectus and any applicable supplements and the Fund’s next prospectus, which we expect to be available by January 1, 2025, at https://www.franklintempleton.com/regulatory-fund-documents or upon request at (800) DIAL BEN/342-5236 or funddocuments putnam.com . | |
| Updated Prospectus Phone Number | (800) DIAL BEN/342-5236 | |
| Updated Prospectus Email Address | funddocuments@putnam.com | |
| Updated Prospectus Web Address | https://www.franklintempleton.com/regulatory-fund-documents | |
| [1] * Reflects fee waivers and/or expense reimbursements, without which expenses would have been higher. * Includes derivatives, if applicable. Cash and Equivalents, if any, represent the market value weights of cash, derivatives, short-term securities, and other unclassified assets in the portfolio. Holdings and allocations may vary over time. | ||
| Shareholder Report, Line Graph (Details) - USD ($) | 12 Months Ended | |||
| Aug. 31, 2024 | Aug. 31, 2023 | Aug. 31, 2022 | Aug. 31, 2021 | |
| Putnam Sustainable Leaders ETF | ||||
| Account Value [Line Items] | ||||
| Line Graph and Table Measure Name | Putnam Sustainable Leaders ETF (NAV) | |||
| Account Value | $ 13,450 | $ 10,189 | $ 8,827 | $ 10,976 |
| Russell 3000 Index [Member] | ||||
| Account Value [Line Items] | ||||
| Line Graph and Table Measure Name | Russell 3000 Index | |||
| Account Value | $ 13,545 | 10,714 | 9,336 | 10,766 |
| ETF Market [Member] | ||||
| Account Value [Line Items] | ||||
| Line Graph and Table Measure Name | Putnam Sustainable Leaders ETF (Market Price) | |||
| Account Value | $ 13,448 | 10,195 | 8,841 | 10,980 |
| S&P 500 Index [Member] | ||||
| Account Value [Line Items] | ||||
| Line Graph and Table Measure Name | S&P 500 Index | |||
| Account Value | $ 14,183 | $ 11,189 | $ 9,650 | $ 10,870 |
| Shareholder Report, Average Annual Return (Details) | 12 Months Ended | 39 Months Ended |
| Aug. 31, 2024 | Aug. 31, 2024 | |
| Putnam Sustainable Leaders ETF | ||
| Average Annual Return [Line Items] | ||
| Line Graph and Table Measure Name | Putnam Sustainable Leaders ETF (NAV) | |
| Average Annual Return, Percent | 32% | 9.50% |
| Russell 3000 Index [Member] | ||
| Average Annual Return [Line Items] | ||
| Line Graph and Table Measure Name | Russell 3000 Index | |
| Average Annual Return, Percent | 26.14% | 9.74% |
| ETF Market [Member] | ||
| Average Annual Return [Line Items] | ||
| Line Graph and Table Measure Name | Putnam Sustainable Leaders ETF (Market Price) | |
| Average Annual Return, Percent | 31.91% | 9.50% |
| S&P 500 Index [Member] | ||
| Average Annual Return [Line Items] | ||
| Line Graph and Table Measure Name | S&P 500 Index | |
| Average Annual Return, Percent | 27.14% | 11.29% |
| Label | Element | Value |
| Putnam Sustainable Leaders ETF | Information Technology [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 34.80% |
| Putnam Sustainable Leaders ETF | Health Care [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 14.70% |
| Putnam Sustainable Leaders ETF | Consumer Discretionary [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 12.10% |
| Putnam Sustainable Leaders ETF | Financials [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 12% |
| Putnam Sustainable Leaders ETF | Industrials [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 5.80% |
| Putnam Sustainable Leaders ETF | Materials [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 5.70% |
| Putnam Sustainable Leaders ETF | Consumer Staples [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 5.20% |
| Putnam Sustainable Leaders ETF | Real Estate [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 3.30% |
| Putnam Sustainable Leaders ETF | Utilities [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 2.80% |
| Putnam Sustainable Leaders ETF | Communication Services [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 2.10% |
| Putnam Sustainable Leaders ETF | Cash and Equivalents [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Net Asset Value | oef_PctOfNav | 1.50% |
