v3.26.1
Shareholder Report, Line Graph (Details) 1014013_Franklin U.S. Equity Index 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
Mar. 31, 2019
Mar. 31, 2018
Mar. 31, 2017
Jun. 01, 2016
Mar. 31, 2026
Franklin U.S. Equity Index ETF                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     Franklin U.S. Equity Index ETF (NAV)
Accumulated Value $ 23,964 $ 22,169 $ 17,009 $ 18,615 $ 17,078 $ 11,815 $ 13,205 $ 12,517 $ 10,995 $ 10,000 $ 28,152
Morningstar US Target Market Exposure Index [Member]                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     Morningstar US Target Market Exposure Index
Linked Morningstar US Target Market Exposure Index [Member]                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     Linked Morningstar US Target Market Exposure Index
Accumulated Value $ 23,661 $ 21,880 $ 16,788 $ 18,360 $ 16,837 $ 11,661 $ 13,027 $ 12,351 $ 10,838 $ 10,000 $ 27,809