v3.25.3
S000003995 [Member] Expense Example, No Redemption - Putnam Sustainable Retirement 2050 Fund - Class C
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 1,014
Expense Example, No Redemption, 10 Years $ 2,222