Document And Entity Information [Abstract] - shares	1 Months Ended	6 Months Ended		11 Months Ended	12 Months Ended
	Dec. 29, 2023	Dec. 30, 2022	Jun. 16, 2022	Nov. 14, 2023	Dec. 27, 2024	Dec. 29, 2023	Feb. 28, 2025
Document and Entity Information [Abstract]
Document Type					10-K
Document Annual Report					true
Document Period End Date					Dec. 27, 2024
Document Transition Report					false
Entity File Number					001-35803
Entity Registrant Name					Mallinckrodt plc
Entity Incorporation, State or Country Code					L2
Entity Tax Identification Number					98-1088325
Entity Central Index Key					0001567892
Current Fiscal Year End Date					--12-27
Document Fiscal Year Focus					2024
Document Fiscal Period Focus					FY
Amendment Flag					false
Entity Address, Address Line One					College Business & Technology Park
Entity Address, Address Line Two					Cruiserath
Entity Address, Address Line Three					Blanchardstown
Entity Address, City or Town					Dublin
Entity Address, Postal Zip Code					15
Entity Address, Country					IE
Country Region					353
City Area Code					1
Local Phone Number					696 0000
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
Entity Shell Company					false
Entity Common Stock, Shares Outstanding							19,762,306
ICFR Auditor Attestation Flag					false
Auditor Firm ID					238	34
Auditor Name					PricewaterhouseCoopers LLP	Deloitte & Touche LLP
Auditor Location					St. Louis, Missouri	St. Louis, Missouri
Title of 12(b) Security					Ordinary shares, par value $0.01 per share
Financial Designation, Predecessor and Successor	Successor	Predecessor	Predecessor	Predecessor	Successor
Document Financial Statement Error Correction [Flag]					false