Shareholder Report, Line Graph (Details) 74200010400_Franklin Federal Tax-Free Income Fund_Class C_TSR Annual {Class C} - USD ($) |
12 Months Ended | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Apr. 30, 2025 |
Apr. 30, 2024 |
Apr. 30, 2023 |
Apr. 30, 2022 |
Apr. 30, 2021 |
Apr. 30, 2020 |
Apr. 30, 2019 |
Apr. 30, 2018 |
Apr. 30, 2017 |
Apr. 30, 2016 |
Apr. 30, 2026 |
|
| Class C | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Class C (with sales charge) | ||||||||||
| Accumulated Value | $ 10,867 | $ 10,676 | $ 10,414 | $ 10,365 | $ 11,390 | $ 10,490 | $ 10,421 | $ 9,982 | $ 9,945 | $ 10,000 | $ 11,499 |
| Bloomberg Municipal Bond Index [Member] | |||||||||||
| Account Value [Line Items] | |||||||||||
| Line Graph and Table Measure Name | Bloomberg Municipal Bond Index | ||||||||||
| Accumulated Value | $ 11,688 | $ 11,497 | $ 11,262 | $ 10,947 | $ 11,884 | $ 11,030 | $ 10,797 | $ 10,170 | $ 10,014 | $ 10,000 | $ 12,429 |