The fund invests in a diversified portfolio of fixed income securities. The fund’s investments may include corporate credit, including investment-grade debt, bank loans and structured credit; sovereign debt, including obligations of governments in developed and emerging markets; and securitized assets, including asset-backed securities, residential mortgage-backed securities (which may be backed by non-qualified or “sub-prime” mortgages), commercial mortgage-backed securities and collateralized mortgage obligations.

The fund may invest up to 5% of its total assets in debt investments rated below BBB or its equivalent (also known as below-investment-grade securities) at the time of purchase by each rating agency rating such investments, or in unrated investments that the Investment Manager believes are of comparable quality. However, the fund will not invest in securities that are rated lower than B or its equivalent by each rating agency rating the investment, or are unrated

securities that the Investment Manager believes are of comparable quality. The fund will not necessarily sell an investment if its rating is reduced (or increased) after purchase.

Under normal circumstances, the fund will invest at least 80% of its net assets in bonds (bonds include any debt instrument, and may be represented by other investment instruments, including derivatives). This policy may be changed only after 60 days’ notice to shareholders. The fund normally maintains an effective duration of three years or less. Effective duration provides a measure of a fund’s interest-rate sensitivity. The longer a fund’s duration, the more sensitive the fund is to shifts in interest rates.

The Investment Manager may consider, among other factors, credit, interest rate and prepayment risks, as well as general market conditions, when deciding whether to buy or sell investments. The Investment Manager may also use derivatives, such as futures, options, certain foreign currency transactions and swap contracts, for both hedging and non-hedging purposes.

The fund may invest in securities that are purchased in private placements, which may be illiquid because they are subject to restrictions on resale.

S000024274 [Member] Investment Strategy - Putnam Short Duration Bond Fund	Oct. 31, 2025
Prospectus [Line Items]
Strategy [Heading]	Investments, risks, and performance Investments
Strategy Narrative [Text Block]	The fund invests in a diversified portfolio of fixed income securities. The fund’s investments may include corporate credit, including investment-grade debt, bank loans and structured credit; sovereign debt, including obligations of governments in developed and emerging markets; and securitized assets, including asset-backed securities, residential mortgage-backed securities (which may be backed by non-qualified or “sub-prime” mortgages), commercial mortgage-backed securities and collateralized mortgage obligations. The fund may invest up to 5% of its total assets in debt investments rated below BBB or its equivalent (also known as below-investment-grade securities) at the time of purchase by each rating agency rating such investments, or in unrated investments that the Investment Manager believes are of comparable quality. However, the fund will not invest in securities that are rated lower than B or its equivalent by each rating agency rating the investment, or are unrated securities that the Investment Manager believes are of comparable quality. The fund will not necessarily sell an investment if its rating is reduced (or increased) after purchase. Under normal circumstances, the fund will invest at least 80% of its net assets in bonds (bonds include any debt instrument, and may be represented by other investment instruments, including derivatives). This policy may be changed only after 60 days’ notice to shareholders. The fund normally maintains an effective duration of three years or less. Effective duration provides a measure of a fund’s interest-rate sensitivity. The longer a fund’s duration, the more sensitive the fund is to shifts in interest rates. The Investment Manager may consider, among other factors, credit, interest rate and prepayment risks, as well as general market conditions, when deciding whether to buy or sell investments. The Investment Manager may also use derivatives, such as futures, options, certain foreign currency transactions and swap contracts, for both hedging and non-hedging purposes. The fund may invest in securities that are purchased in private placements, which may be illiquid because they are subject to restrictions on resale.