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 MORTGAGE SECURITIES FUND | Class A Shares | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 10.28% | 4.44% | 3.66% | (10.82%) | (4.22%) | (0.71%) | 12.40% | (0.79%) | 0.82% | 0.63% |