v3.26.3
Shareholder Report, Line Graph (Details) LMF5100_Western Asset Municipal High Income Fund_Class I_TSR Annual {Class I} - USD ($)
12 Months Ended
Jul. 31, 2025
Jul. 31, 2024
Jul. 31, 2023
Jul. 31, 2022
Jul. 31, 2021
Jul. 31, 2020
Jul. 31, 2019
Jul. 31, 2018
Jul. 31, 2017
Jul. 31, 2016
Jul. 31, 2026
Class I                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     Class I
Accumulated Value $ 1,182,718 $ 1,203,674 $ 1,126,418 $ 1,118,961 $ 1,213,459 $ 1,121,653 $ 1,094,373 $ 1,030,391 $ 1,005,448 $ 1,000,000 $ 1,270,524
Bloomberg Municipal Bond Index [Member]                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     Bloomberg Municipal Bond Index
Accumulated Value $ 1,152,226 $ 1,152,257 $ 1,110,684 $ 1,100,466 $ 1,182,379 $ 1,144,719 $ 1,086,501 $ 1,012,527 $ 1,002,565 $ 1,000,000 $ 1,212,892