v3.25.3
S000003995 [Member] Expense Example - Putnam Sustainable Retirement 2050 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 566
Expense Example, with Redemption, 10 Years 1,490
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 487
Expense Example, with Redemption, 10 Years 1,328
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 700
Expense Example, with Redemption, 10 Years 1,771
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 1,159
Expense Example, with Redemption, 10 Years 2,087
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 1,014
Expense Example, with Redemption, 10 Years 2,222
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 833
Expense Example, with Redemption, 10 Years 2,051
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 485
Expense Example, with Redemption, 10 Years 1,320
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 431
Expense Example, with Redemption, 10 Years $ 1,203