v3.25.3
S000003999 [Member] Expense Example - Putnam Sustainable Retirement 2035 Fund
Jul. 31, 2025
USD ($)
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 541
Expense Example, with Redemption, 10 Years 1,397
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 459
Expense Example, with Redemption, 10 Years 1,223
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 674
Expense Example, with Redemption, 10 Years 1,679
Class A  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 657
Expense Example, with Redemption, 3 Years 831
Expense Example, with Redemption, 5 Years 1,136
Expense Example, with Redemption, 10 Years 1,999
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 990
Expense Example, with Redemption, 10 Years 2,134
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 806
Expense Example, with Redemption, 10 Years 1,953
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 459
Expense Example, with Redemption, 10 Years 1,223
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 405
Expense Example, with Redemption, 10 Years $ 1,107