Segment Data (Schedule of Segment Reporting Information by Business Segment) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Mar. 25, 2016	Mar. 27, 2015	Mar. 25, 2016	Mar. 27, 2015
Net sales		$ 918.0	$ 819.0	$ 1,832.8	$ 1,587.2
Operating income		164.4	93.9	343.8	215.5
Intangible asset amortization		(175.0)	(122.9)	(348.4)	(247.7)
Restructuring and related charges, net		(10.4)	(3.6)	(16.8)	(10.9)
Restructuring related accelerated depreciation		(1.7)	(0.1)	(1.8)	(0.2)
Specialty Brands
Restructuring and related charges, net		(8.0)	(0.9)	(9.6)	(15.1)
Specialty Generics
Restructuring and related charges, net		(0.6)	(2.7)	(1.7)	(2.7)
Nuclear Imaging
Restructuring and related charges, net		(0.3)	0.0	(2.5)	7.3
Operating Segments
Net sales		901.6	806.6	1,806.0	1,566.3
Operating income		395.8	319.9	801.0	613.4
Operating Segments | Specialty Brands
Net sales		535.0	334.3	1,078.2	707.9
Operating income		263.1	97.4	535.1	245.6
Operating Segments | Specialty Generics
Net sales		264.4	362.8	522.0	647.0
Operating income		101.6	203.7	219.8	344.2
Operating Segments | Nuclear Imaging
Net sales		102.2	109.5	205.8	211.4
Operating income		31.1	18.8	46.1	23.6
Corporate, Non-Segment
Net sales	[1]	16.4	12.4	26.8	20.9
Corporate and allocated expenses	[2]	(29.1)	(99.5)	(75.1)	(139.3)
Intangible asset amortization		(175.0)	(122.9)	(348.4)	(247.7)
Restructuring and related charges, net	[3]	(10.4)	(3.6)	(16.8)	(10.9)
Impairment Charges, Not Related to Restructuring Activities		$ (16.9)	$ 0.0	$ (16.9)	$ 0.0

[1] Represents historical CMDS-related intercompany transactions that represent Mallinckrodt continuing operations under an ongoing supply agreement with the acquirer of the CMDS business.

[2] Includes administration expenses and certain compensation, environmental and other costs not charged to the Company's operating segments.

[3] Includes restructuring-related accelerated depreciation.