v3.26.1
Shareholder Report, Average Annual Return (Details) 1014018_Franklin U.S. Mid Cap Multifactor Index ETF_Single Class_TSR Annual {Single Class}
12 Months Ended 60 Months Ended 107 Months Ended
Mar. 31, 2026
Mar. 31, 2026
Mar. 31, 2026
Franklin U.S. Mid Cap Multifactor Index ETF      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Franklin U.S. Mid Cap Multifactor Index ETF (NAV)    
Average Annual Return, Percent 5.33% 7.54% 10.46%
Russell 3000 Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Russell 3000 Index    
Average Annual Return, Percent 18.09% 10.87% 13.19%
Russell Midcap Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Russell Midcap Index    
Average Annual Return, Percent 15.98% 7.26% 10.15%
LibertyQ U.S. Mid Cap Equity Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name LibertyQ U.S. Mid Cap Equity Index    
Average Annual Return, Percent 5.64% 7.84% 10.77%