Segment Data (Schedule of Net Sales from External Customers by Products) (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 25, 2015	Dec. 26, 2014
Segment Reporting Information [Line Items]
Net sales		$ 914.8	$ 768.2
Operating Segments
Segment Reporting Information [Line Items]
Net sales		904.4	759.7
Operating Segments | Specialty Brands
Segment Reporting Information [Line Items]
Net sales		543.2	373.6
Operating Segments | Specialty Generics
Segment Reporting Information [Line Items]
Net sales		257.6	284.2
Operating Segments | Nuclear Imaging
Segment Reporting Information [Line Items]
Net sales		103.6	101.9
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Net sales	[1]	10.4	8.5
H. P. Acthar Gel | Operating Segments | Specialty Brands
Segment Reporting Information [Line Items]
Net sales		286.7	266.4
Ofirmev | Operating Segments | Specialty Brands
Segment Reporting Information [Line Items]
Net sales		66.9	71.4
Therakos | Operating Segments | Specialty Brands
Segment Reporting Information [Line Items]
Net sales		50.4	0.0
Inomax | Operating Segments | Specialty Brands
Segment Reporting Information [Line Items]
Net sales		110.8	0.0
Other | Operating Segments | Specialty Brands
Segment Reporting Information [Line Items]
Net sales		28.4	35.8
Other | Operating Segments | Specialty Generics
Segment Reporting Information [Line Items]
Net sales		51.1	42.7
Oxycodone (API) | Operating Segments | Specialty Generics
Segment Reporting Information [Line Items]
Net sales		28.9	47.0
Hydrocodone (API) | Operating Segments | Specialty Generics
Segment Reporting Information [Line Items]
Net sales		36.7	34.0
Methylphenidate ER (Specialty Generics) | Operating Segments | Specialty Generics
Segment Reporting Information [Line Items]
Net sales		31.2	48.6
Other Controlled Substances | Operating Segments | Specialty Generics
Segment Reporting Information [Line Items]
Net sales		$ 109.7	$ 111.9

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