v3.25.3
S000030470 [Member] Expense Example - Putnam Sustainable Retirement 2055 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 713
Expense Example, with Redemption, 10 Years 1,820
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 580
Expense Example, with Redemption, 10 Years 1,542
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 499
Expense Example, with Redemption, 10 Years 1,371
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 445
Expense Example, with Redemption, 10 Years 1,256
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 499
Expense Example, with Redemption, 10 Years 1,371
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 1,173
Expense Example, with Redemption, 10 Years 2,136
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 1,028
Expense Example, with Redemption, 10 Years 2,271
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 845
Expense Example, with Redemption, 10 Years $ 2,093