S000070577 [Member] Shareholder Fees - Putnam Sustainable Retirement 2065 Fund	Jul. 31, 2025
Class R3
Prospectus [Line Items]
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)	0.00%
Maximum Deferred Sales Charge (as a percentage)	0.00%
Class Y
Prospectus [Line Items]
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)	0.00%
Maximum Deferred Sales Charge (as a percentage)	0.00%
Class R6
Prospectus [Line Items]
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)	0.00%
Maximum Deferred Sales Charge (as a percentage)	0.00%
Class R5
Prospectus [Line Items]
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)	0.00%
Maximum Deferred Sales Charge (as a percentage)	0.00%
Class R4
Prospectus [Line Items]
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)	0.00%
Maximum Deferred Sales Charge (as a percentage)	0.00%
Class A
Prospectus [Line Items]
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)	5.75%
Maximum Deferred Sales Charge (as a percentage)	1.00%	[1]
Class R
Prospectus [Line Items]
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)	0.00%
Maximum Deferred Sales Charge (as a percentage)	0.00%
Class C
Prospectus [Line Items]
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price)	0.00%
Maximum Deferred Sales Charge (as a percentage)	1.00%	[2]

[1] Applies only to certain redemptions of shares bought with no initial sales charge.

[2] This charge is eliminated after one year.