Shareholder Report, Average Annual Return (Details) 1014050_Franklin Ultra Short Bond ETF_Single Class_TSR Annual {Single Class} |
12 Months Ended | 60 Months Ended | 69 Months Ended |
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2026 |
Mar. 31, 2026 |
|
| Franklin Ultra Short Bond ETF | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Franklin Ultra Short Bond ETF (NAV) | ||
| Average Annual Return, Percent | 4.59% | 3.49% | 3.21% |
| 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% | (0.22%) |
| ICE BofA U.S. 3-Month Treasury Bill Index [Member] | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | ICE BofA U.S. 3-Month Treasury Bill Index | ||
| Average Annual Return, Percent | 4.00% | 3.34% | 2.93% |