v3.25.4
Average Annual Total Returns - NORTHEAST INVESTORS TRUST
 12 Months Ended 60 Months Ended 120 Months Ended
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
ICE Bank of America Merrill Lynch U.S. High Yield Index      
Prospectus [Line Items]      
Average Annual Return, Percent [1] 8.50% 4.50% 6.45%
NORTHEAST INVESTORS TRUST Shares      
Prospectus [Line Items]      
Average Annual Return, Percent 10.26% 6.03% 4.38%
NORTHEAST INVESTORS TRUST Shares | After Taxes on Distributions      
Prospectus [Line Items]      
Average Annual Return, Percent 8.18% 3.78% 2.01%
NORTHEAST INVESTORS TRUST Shares | After Taxes on Distributions and Sales      
Prospectus [Line Items]      
Average Annual Return, Percent 6.02% 3.62% 2.26%
[1] The ICE Bank of America Merrill Lynch U.S. High Yield Index is an unmanaged market capitalization-weighted index comprised of all domestic and yankee high-yield bonds, including deferred interest bonds and payment-in-kind securities. Bonds included in the index have maturities of one year or more and have a below investment grade rating, but are not in default. It is shown for comparative purposes only and reflects no deductions for fees, expenses or taxes.