v3.26.3
Shareholder Report, Line Graph (Details) LMF5900_Western Asset Short Duration High Income Fund_Class R_TSR Annual {Class R} - 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 R                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     Class R
Accumulated Value $ 15,313 $ 14,258 $ 13,160 $ 12,380 $ 13,192 $ 11,800 $ 11,871 $ 11,446 $ 11,021 $ 10,000 $ 16,076
Bloomberg U.S. Aggregate Index [Member]                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     Bloomberg U.S. Aggregate Index
Accumulated Value 11,130 10,766 10,243 10,600 11,664 11,746 10,666 9,869 9,949 10,000 $ 11,431
Bloomberg US High Yield 1-5 Year Cash Pay 2% Constrained Index [Member]                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     Bloomberg U.S. High Yield 1-5 Year Cash Pay 2% Constrained Index
Accumulated Value $ 16,362 $ 15,053 $ 13,634 $ 12,866 $ 13,447 $ 12,039 $ 12,041 $ 11,508 $ 11,041 $ 10,000 $ 17,174