Document And Entity Information [Abstract] - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Nov. 23, 2016	Mar. 25, 2016
Document And Entity Information [Abstract]
Entity Common Stock, Shares Outstanding		105,858,223
Entity Registrant Name	Mallinckrodt plc
Entity Central Index Key	0001567892
Trading Symbol	MNK
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 6,564.4