v3.25.4
Expense Example - PUTNAM MORTGAGE SECURITIES FUND
Sep. 30, 2025
USD ($)
Class A Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 490
Expense Example, with Redemption, 3 Years 682
Expense Example, with Redemption, 5 Years 890
Expense Example, with Redemption, 10 Years 1,487
Class C Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 270
Expense Example, with Redemption, 3 Years 526
Expense Example, with Redemption, 5 Years 907
Expense Example, with Redemption, 10 Years 1,777
Class R Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 119
Expense Example, with Redemption, 3 Years 372
Expense Example, with Redemption, 5 Years 644
Expense Example, with Redemption, 10 Years 1,420
Class Y Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 68
Expense Example, with Redemption, 3 Years 214
Expense Example, with Redemption, 5 Years 373
Expense Example, with Redemption, 10 Years 834
Class R6 Shares  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 52
Expense Example, with Redemption, 3 Years 163
Expense Example, with Redemption, 5 Years 284
Expense Example, with Redemption, 10 Years $ 639