Shareholder Report, Average Annual Return (Details) 74200010400_Franklin Federal Tax-Free Income Fund_Class R6_TSR Annual {Class R6} |
12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|
Apr. 30, 2026 |
Apr. 30, 2026 |
Apr. 30, 2026 |
|
| Class R6 | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Class R6 | ||
| Average Annual Return, Percent | 6.55% | 0.89% | 2.07% |
| Bloomberg Municipal Bond Index [Member] | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond Index | ||
| Average Annual Return, Percent | 6.34% | 0.90% | 2.20% |