Shareholder Report, Average Annual Return (Details) 74200010400_Franklin Federal Tax-Free Income Fund_Class A_TSR Annual {Class A} |
12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|
Apr. 30, 2026 |
Apr. 30, 2026 |
Apr. 30, 2026 |
|
| Class A | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Class A (with sales charge) | ||
| Average Annual Return, Percent | 2.25% | (0.17%) | 1.46% |
| Without Sales Load [Member] | Class A | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Class A | ||
| Average Annual Return, Percent | 6.24% | 0.59% | 1.85% |
| 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% |