v3.25.3
S000003996 [Member] Expense Example - Putnam Sustainable Retirement Maturity Fund
Jul. 31, 2025
USD ($)
Class R3  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 102
Expense Example, with Redemption, 3 Years 318
Expense Example, with Redemption, 5 Years 666
Expense Example, with Redemption, 10 Years 1,647
Class R4  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 77
Expense Example, with Redemption, 3 Years 240
Expense Example, with Redemption, 5 Years 532
Expense Example, with Redemption, 10 Years 1,363
Class R5  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 61
Expense Example, with Redemption, 3 Years 192
Expense Example, with Redemption, 5 Years 453
Expense Example, with Redemption, 10 Years 1,199
Class A  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 483
Expense Example, with Redemption, 3 Years 660
Expense Example, with Redemption, 5 Years 964
Expense Example, with Redemption, 10 Years 1,825
Class C  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 263
Expense Example, with Redemption, 3 Years 505
Expense Example, with Redemption, 5 Years 980
Expense Example, with Redemption, 10 Years 2,103
Class R  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 127
Expense Example, with Redemption, 3 Years 396
Expense Example, with Redemption, 5 Years 800
Expense Example, with Redemption, 10 Years 1,931
Class Y  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 61
Expense Example, with Redemption, 3 Years 192
Expense Example, with Redemption, 5 Years 453
Expense Example, with Redemption, 10 Years 1,199
Class R6  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 51
Expense Example, with Redemption, 3 Years 160
Expense Example, with Redemption, 5 Years 397
Expense Example, with Redemption, 10 Years $ 1,079