Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 30, 2020
Document and Entity Information
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Entity Registrant Name	ENZON PHARMACEUTICALS, INC.
Entity Central Index Key	0000727510
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Title of 12(b) Security	None
Security Exchange Name	NONE
Trading Symbol	ENZN
Entity Common Stock, Shares Outstanding		74,214,603
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Interactive Data Current	Yes