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Shareholder Report, Average Annual Return (Details) 1014046_Franklin U.S. Core Bond ETF_Single Class_TSR Annual {Single Class}
12 Months Ended 60 Months Ended 78 Months Ended
Mar. 31, 2026
Mar. 31, 2026
Mar. 31, 2026
Franklin U.S. Core Bond ETF      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Franklin U.S. Core Bond ETF (NAV)    
Average Annual Return, Percent 4.33% 0.19% 0.93%
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% 0.98%