v3.26.1
Shareholder Report, Average Annual Return (Details) LMF1700_Western Asset Ultra-Short Income Fund_Class A_TSR Annual {Class A}
12 Months Ended 60 Months Ended 120 Months Ended
May 31, 2026
May 31, 2026
May 31, 2026
Class A      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Class A    
Average Annual Return, Percent 4.71% 3.57% 3.03%
Bloomberg U.S. Aggregate Index      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Bloomberg U.S. Aggregate Index    
Average Annual Return, Percent 5.13% 0.17% 1.70%
ICE BofA 3-Month U.S. Treasury Bill Index      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name ICE BofA 3-Month U.S. Treasury Bill Index    
Average Annual Return, Percent 3.88% 3.46% 2.32%