Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2024	Apr. 28, 2025	Jun. 28, 2024
Document and Entity Information [Abstract]
Document Type	10-K/A
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2024
Entity File Number	000-12957
Entity Registrant Name	Enzon Pharmaceuticals, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	22-2372868
Entity Address State Or Province	NJ
Entity Address, Address Line One	20 Commerce Drive (Suite 135),
Entity Address, City or Town	Cranford
Entity Address, Postal Zip Code	07016
City Area Code	732
Local Phone Number	980-4500
Title of 12(b) Security	None
Trading Symbol	ENZN
No Trading Symbol Flag	true
Security Exchange Name	NONE
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Document Financial Statement Error Correction [Flag]	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 6,814,434
Entity Common Stock, Shares Outstanding		74,214,603
Entity Central Index Key	0000727510
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Amendment Flag	true
Amendment Description	Enzon Pharmaceuticals, Inc. (the "Company," "we," "us," or "our") is filing this Amendment No. 1 on Form 10 K/A (this "Amendment No. 1") to amend our Annual Report on Form 10 K for the year ended December 31, 2024, originally filed with the Securities and Exchange Commission (the "SEC") on February 21, 2025 (our "Annual Report"). We are amending our Annual Report to include the information required by Items 10 through 14 of Part III of Form 10 K (the "Part III Information"). The Part III Information, pursuant to General Instruction G(3), is required to be filed no later than 120 days after our fiscal year-end. Pursuant to the rules of the SEC, Part IV, Item 15 has also been amended to contain the currently dated certification from the Company's principal executive officer who is also the Company's principal financial officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002. The certification of the Company's principal executive officer and principal financial officer are attached to this Amendment No. 1 as Exhibit 31.1. Because no financial statements have been included in this Amendment No. 1 and this Amendment No. 1 does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4 and 5 of the certification have been omitted. Additionally, we are not including a currently dated certification under Section 906 of the Sarbanes-Oxley Act of 2002 as no financial statements are being filed with this Amendment No. 1. Furthermore, Item 15 is also being amended to include the Company's trading policy as Exhibit 19.1. This Amendment No. 1 does not amend any other information set forth in our Annual Report and we have not updated disclosures included therein to reflect any subsequent events. This Amendment No. 1 should be read in conjunction with our Annual Report and with our filings with the SEC subsequent to our Annual Report.
Auditor Name	EisnerAmper LLP
Auditor Location	Philadelphia, Pennsylvania
Auditor Firm ID	274