Shareholder Report, Line Graph (Details) 1014051_Franklin U.S. Treasury Bond ETF_Single Class_TSR Annual {Single Class} - USD ($) |
12 Months Ended | ||||||
|---|---|---|---|---|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
Mar. 31, 2023 |
Mar. 31, 2022 |
Mar. 31, 2021 |
Jun. 09, 2020 |
Mar. 31, 2026 |
|
| Franklin U.S. Treasury Bond ETF | |||||||
| Account Value [Line Items] | |||||||
| Line Graph and Table Measure Name | Franklin U.S. Treasury Bond ETF (NAV) | ||||||
| Accumulated Value | $ 9,384 | $ 8,973 | $ 8,972 | $ 9,340 | $ 9,664 | $ 10,000 | $ 9,704 |
| Bloomberg U.S. Aggregate Index [Member] | |||||||
| Account Value [Line Items] | |||||||
| Line Graph and Table Measure Name | Bloomberg U.S. Aggregate Index | ||||||
| Accumulated Value | 9,527 | 9,084 | 8,932 | 9,381 | 9,788 | 10,000 | $ 9,942 |
| Bloomberg U.S. Treasury Index [Member] | |||||||
| Account Value [Line Items] | |||||||
| Line Graph and Table Measure Name | Bloomberg U.S. Treasury Index | ||||||
| Accumulated Value | $ 9,149 | $ 8,754 | $ 8,750 | $ 9,163 | $ 9,512 | $ 10,000 | $ 9,447 |