v3.26.1
Shareholder Report, Line Graph (Details) 1014046_Franklin U.S. Core Bond ETF_Single Class_TSR Annual {Single Class} - USD ($)
12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2023
Mar. 31, 2022
Mar. 31, 2021
Mar. 31, 2020
Sep. 17, 2019
Mar. 31, 2026
Franklin U.S. Core Bond ETF                
Account Value [Line Items]                
Line Graph and Table Measure Name               Franklin U.S. Core Bond ETF (NAV)
Accumulated Value $ 10,185 $ 9,701 $ 9,539 $ 10,029 $ 10,526 $ 10,313 $ 10,000 $ 10,626
Bloomberg U.S. Aggregate Index [Member]                
Account Value [Line Items]                
Line Graph and Table Measure Name               Bloomberg U.S. Aggregate Index
Accumulated Value $ 10,130 $ 9,659 $ 9,498 $ 9,975 $ 10,407 $ 10,333 $ 10,000 $ 10,571