v3.25.3
S000051718 [Member] Expense Example, No Redemption - Putnam Sustainable Retirement 2060 Fund - Class C Shares
Jul. 31, 2025
USD ($)
Prospectus [Line Items]  
Expense Example, No Redemption, 1 Year $ 163
Expense Example, No Redemption, 3 Years 505
Expense Example, No Redemption, 5 Years 871
Expense Example, No Redemption, 10 Years $ 1,699