Segment Data (Schedule of Net Sales from External Customers by Products) (Details) - USD ($) $ in Millions		3 Months Ended
		Dec. 30, 2016	Dec. 25, 2015
Segment Reporting Information [Line Items]
Net sales		$ 829.9	$ 811.2
Operating Segments
Segment Reporting Information [Line Items]
Net sales		816.0	800.8
Operating Segments | Specialty Brands
Segment Reporting Information [Line Items]
Net sales		603.1	543.2
Operating Segments | Specialty Generics
Segment Reporting Information [Line Items]
Net sales		212.9	257.6
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Net sales	[1]	13.9	10.4
H. P. Acthar Gel | Operating Segments | Specialty Brands
Segment Reporting Information [Line Items]
Net sales		325.4	286.7
Hemostasis Products | Operating Segments | Specialty Brands
Segment Reporting Information [Line Items]
Net sales		13.4	0.0
Ofirmev | Operating Segments | Specialty Brands
Segment Reporting Information [Line Items]
Net sales		72.5	66.9
Therakos | Operating Segments | Specialty Brands
Segment Reporting Information [Line Items]
Net sales		47.4	50.4
Inomax | Operating Segments | Specialty Brands
Segment Reporting Information [Line Items]
Net sales		118.3	110.8
Other | Operating Segments | Specialty Brands
Segment Reporting Information [Line Items]
Net sales		26.1	28.4
Other | Operating Segments | Specialty Generics
Segment Reporting Information [Line Items]
Net sales		38.5	51.1
Oxycodone (API) | Operating Segments | Specialty Generics
Segment Reporting Information [Line Items]
Net sales		24.3	28.9
Hydrocodone (API) | Operating Segments | Specialty Generics
Segment Reporting Information [Line Items]
Net sales		23.2	36.7
Methylphenidate ER (Specialty Generics) | Operating Segments | Specialty Generics
Segment Reporting Information [Line Items]
Net sales		22.0	31.2
Other Controlled Substances | Operating Segments | Specialty Generics
Segment Reporting Information [Line Items]
Net sales		$ 104.9	$ 109.7

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