Putnam Floating Rate Income Fund S000000773 [Member] Bloomberg U.S. Aggregate Index (no deduction for fees, expenses or taxes) Bloomberg U S Aggregate Index [Member] Morningstar LSTA U.S. Leveraged Loan Index (no deduction for fees, expenses or taxes) Morningstar LSTA U S Leveraged Loan Index [Member] Class B shares C000002278 [Member] Class C C000002279 [Member] Class M shares C000002280 [Member] Class R C000002281 [Member] Class Y C000002282 [Member] Class A C000002283 [Member] Class T Shares C000185578 [Member] Class R6 C000203062 [Member] Focus of investments risk [Member] Interest rate risks [Member] Credit risks [Member] Impairment of collateral risk [Member] Floating rate loan liquidity risk [Member] Prepayment risks [Member] Derivatives risks [Member] Foreign investments risk [Member] Large shareholder transaction risk [Member] Management and operational risk [Member] Market risks [Member]