Shareholder Report, Average Annual Return (Details) 1014051_Franklin U.S. Treasury Bond ETF_Single Class_TSR Annual {Single Class} |
12 Months Ended | 60 Months Ended | 70 Months Ended |
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2026 |
Mar. 31, 2026 |
|
| Franklin U.S. Treasury Bond ETF | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Franklin U.S. Treasury Bond ETF (NAV) | ||
| Average Annual Return, Percent | 3.41% | 0.08% | (0.52%) |
| Bloomberg U.S. Aggregate Index [Member] | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Bloomberg U.S. Aggregate Index | ||
| Average Annual Return, Percent | 4.35% | 0.31% | 0.02% |
| Bloomberg U.S. Treasury Index [Member] | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Bloomberg U.S. Treasury Index | ||
| Average Annual Return, Percent | 3.25% | (0.14%) | (0.79%) |