v3.26.1
Annual Total Returns - Z
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
BNY Mellon AMT-Free Municipal Bond Fund                    
Prospectus [Line Items]                    
Annual Return [Percent] 2.33% 6.49% (9.41%) 1.60% 4.87% 7.87% 0.74% 5.61% (0.10%) 3.92%
BNY Mellon High Yield Municipal Bond Fund                    
Prospectus [Line Items]                    
Annual Return [Percent] 4.34% 7.25% (16.79%) 6.13% 2.83% 10.11% 1.64% 13.10% 0.52% 5.24%