v3.25.3
S000003997 [Member] Expense Example - Putnam Sustainable Retirement 2045 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 560
Expense Example, with Redemption, 10 Years 1,467
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 692
Expense Example, with Redemption, 10 Years 1,746
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 478
Expense Example, with Redemption, 10 Years 1,293
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 1,153
Expense Example, with Redemption, 10 Years 2,064
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 1,008
Expense Example, with Redemption, 10 Years 2,199
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 825
Expense Example, with Redemption, 10 Years 2,019
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 478
Expense Example, with Redemption, 10 Years 1,293
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 423
Expense Example, with Redemption, 10 Years $ 1,175