| Putnam Sustainable Retirement 2050 Fund | Class A Shares | — | — |
| Putnam Sustainable Retirement 2050 Fund | Class C Shares | — | — |
| Putnam Sustainable Retirement 2050 Fund | Class R Shares | — | — |
| Putnam Sustainable Retirement 2050 Fund | Class Y Shares | — | — |
| Putnam Sustainable Retirement 2050 Fund | Class R6 Shares | — | — |
| Putnam Sustainable Retirement 2050 Fund | Class R4 Shares | — | — |
| Putnam Sustainable Retirement 2050 Fund | Class R5 Shares | — | — |
| Putnam Sustainable Retirement 2050 Fund | Class R3 Shares | — | — |
| Putnam Sustainable Retirement Maturity Fund | Class A Shares | — | — |
| Putnam Sustainable Retirement Maturity Fund | Class C Shares | — | — |
| Putnam Sustainable Retirement Maturity Fund | Class R Shares | — | — |
| Putnam Sustainable Retirement Maturity Fund | Class Y Shares | — | — |
| Putnam Sustainable Retirement Maturity Fund | Class R6 Shares | — | — |
| Putnam Sustainable Retirement Maturity Fund | Class R3 Shares | — | — |
| Putnam Sustainable Retirement Maturity Fund | Class R4 Shares | — | — |
| Putnam Sustainable Retirement Maturity Fund | Class R5 Shares | — | — |
| Putnam Sustainable Retirement 2045 Fund | Class A Shares | — | — |
| Putnam Sustainable Retirement 2045 Fund | Class C Shares | — | — |
| Putnam Sustainable Retirement 2045 Fund | Class R Shares | — | — |
| Putnam Sustainable Retirement 2045 Fund | Class Y Shares | — | — |
| Putnam Sustainable Retirement 2045 Fund | Class R6 Shares | — | — |
| Putnam Sustainable Retirement 2045 Fund | Class R4 Shares | — | — |
| Putnam Sustainable Retirement 2045 Fund | Class R3 Shares | — | — |
| Putnam Sustainable Retirement 2045 Fund | Class R5 Shares | — | — |
| Putnam Sustainable Retirement 2040 Fund | Class A Shares | — | — |