v3.26.1
Shareholder Report, Line Graph (Details) LMF1700_Western Asset Ultra-Short Income Fund_Class A_TSR Annual {Class A} - USD ($)
12 Months Ended
May 31, 2025
May 31, 2024
May 31, 2023
May 31, 2022
May 31, 2021
May 31, 2020
May 31, 2019
May 31, 2018
May 31, 2017
May 31, 2016
May 31, 2026
Class A                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     Class A
Accumulated Value $ 12,868 $ 12,215 $ 11,434 $ 11,071 $ 11,307 $ 10,955 $ 10,925 $ 10,607 $ 10,372 $ 10,000 $ 13,475
Bloomberg U.S. Aggregate Index                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     Bloomberg U.S. Aggregate Index
Accumulated Value 11,258 10,676 10,538 10,769 11,734 11,781 10,768 10,120 10,158 10,000 $ 11,836
ICE BofA 3-Month U.S. Treasury Bill Index                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     ICE BofA 3-Month U.S. Treasury Bill Index
Accumulated Value $ 12,102 $ 11,552 $ 10,954 $ 10,620 $ 10,605 $ 10,593 $ 10,402 $ 10,172 $ 10,044 $ 10,000 $ 12,572