v3.25.4
S000004000 [Member] Expense Example - Putnam Sustainable Retirement 2030 Fund
Jul. 31, 2025
USD ($)
Class R4  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 87
Expense Example, with Redemption, 3 Years 271
Expense Example, with Redemption, 5 Years 611
Expense Example, with Redemption, 10 Years 1,571
Class R5  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 72
Expense Example, with Redemption, 3 Years 225
Expense Example, with Redemption, 5 Years 531
Expense Example, with Redemption, 10 Years 1,402
Class R6  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 61
Expense Example, with Redemption, 3 Years 192
Expense Example, with Redemption, 5 Years 475
Expense Example, with Redemption, 10 Years 1,285
Class Y  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 72
Expense Example, with Redemption, 3 Years 225
Expense Example, with Redemption, 5 Years 531
Expense Example, with Redemption, 10 Years 1,402
Class A  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 666
Expense Example, with Redemption, 3 Years 860
Expense Example, with Redemption, 5 Years 1,200
Expense Example, with Redemption, 10 Years 2,159
Class C  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 273
Expense Example, with Redemption, 3 Years 536
Expense Example, with Redemption, 5 Years 1,057
Expense Example, with Redemption, 10 Years 2,296
Class R  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 137
Expense Example, with Redemption, 3 Years 427
Expense Example, with Redemption, 5 Years 874
Expense Example, with Redemption, 10 Years 2,118
Class R3  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 112
Expense Example, with Redemption, 3 Years 350
Expense Example, with Redemption, 5 Years 744
Expense Example, with Redemption, 10 Years $ 1,850