v3.25.4
Class A C G P R [Member] N-1A Cover
Sep. 30, 2025
Prospectus [Line Items]  
Document Type 485BPOS
Amendment Flag false
Registrant Name PUTNAM INVESTMENT FUNDS
Entity Central Index Key 0000932101
Entity Investment Company Type N-1A
Document Period End Date Sep. 30, 2025
Prospectus Date Feb. 01, 2026