S000003997 [Member] Annual Total Returns |
12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Putnam Sustainable Retirement 2045 Fund | Class A Shares | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 12.07% | 14.18% | 19.14% | (14.07%) | 14.64% | 11.85% | 19.21% | (9.34%) | 19.26% | 6.87% |