| Label | Element | Value |
|---|---|---|
| Franklin Investment Grade Corporate ETF | Corporate Bonds & Notes [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Total Investments | oef_PctOfTotalInv | 98.50% |
| Franklin Investment Grade Corporate ETF | U.S. Government & Agency Obligations [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Total Investments | oef_PctOfTotalInv | 0.50% |
| Franklin Investment Grade Corporate ETF | Short-Term Investments [Member] | ||
| Holdings [Line Items] | oef_HoldingsLineItems | |
| Percent of Total Investments | oef_PctOfTotalInv | 1.00% |