Document And Entity Information - USD ($) $ in Millions	12 Months Ended
	Sep. 25, 2015	Nov. 16, 2015	Mar. 27, 2015
Document And Entity Information [Abstract]
Entity Registrant Name	Mallinckrodt plc
Entity Central Index Key	0001567892
Trading Symbol	MNK
Current Fiscal Year End Date	--09-25
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Sep. 25, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Amendment Flag	false
Ordinary Shares Outstanding		115,947,044
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 15,146.4