v3.26.1
Shareholder Report, Average Annual Return (Details) 74200006400_Franklin Michigan Tax-Free Income Fund_Class A_TSR Annual {Class A}
12 Months Ended 60 Months Ended 120 Months Ended
Feb. 28, 2026
Feb. 28, 2026
Feb. 28, 2026
Class A      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Class A (with sales charge)    
Average Annual Return, Percent (0.09%) (0.21%) 1.42%
Without Sales Load [Member] | Class A      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Class A    
Average Annual Return, Percent 3.80% 0.56% 1.81%
Bloomberg Municipal Bond Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Bloomberg Municipal Bond Index    
Average Annual Return, Percent 4.96% 1.44% 2.43%