Label	Element	Value
Franklin Municipal Green Bond ETF \| Lease [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	16.80%
Franklin Municipal Green Bond ETF \| Transportation [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	15.80%
Franklin Municipal Green Bond ETF \| Industrial Dev. Revenue and Pollution Control [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	15.80%
Franklin Municipal Green Bond ETF \| Utilities [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	15.10%
Franklin Municipal Green Bond ETF \| Housing [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	11.10%
Franklin Municipal Green Bond ETF \| Special Tax [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	10.10%
Franklin Municipal Green Bond ETF \| Health Care [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	5.40%
Franklin Municipal Green Bond ETF \| Education [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	4.10%
Franklin Municipal Green Bond ETF \| Local [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	3.70%
Franklin Municipal Green Bond ETF \| Other Revenue Bonds [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Total Investments	oef_PctOfTotalInv	2.10%