Acquisitions and License Agreements (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended		6 Months Ended		3 Months Ended
	Aug. 14, 2014	Mar. 19, 2014	Mar. 28, 2014	Mar. 27, 2015	Mar. 28, 2014	Mar. 27, 2015	Dec. 26, 2014
Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Total consideration	$ 5,915.3
Cash received per share (in usd per share)	$ 30.00
Mallinckrodt shares issued per Questcor share (in shares)	0.897
Total Mallinckrodt shares issued with Questcor acquisition (in shares)	57,000,000
Cadence Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Acquisition Costs, Period Cost			17.6
Total consideration		1,329.2
Cash received per share (in usd per share)		$ 14.00
H. P. Acthar Gel | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Number of FDA approved indications	19
Synacthen | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Future milestone payments				215.0
In-process Research and Development | Synacthen | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Discount rate used to value acquired intangible assets	16.00%
Licensing Agreements | Ofirmev | Cadence Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Future milestone payments				25.0
Royalties paid			15.1		5.0
Receivable Securitization | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Cash paid with acquisition	150.0
Senior Notes | 5.75% Senior Notes | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Debt issued with acquisition	900.0
Secured Debt | New Term Loan
Business Acquisition [Line Items]
Interest rate				3.50%		3.50%
Secured Debt | New Term Loan | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Debt issued with acquisition	700.0
Interest rate	3.50%
Secured Debt | Receivable Securitization
Business Acquisition [Line Items]
Interest rate				0.978%		0.978%
Secured Debt | Term Loan
Business Acquisition [Line Items]
Interest rate				3.25%		3.25%
Secured Debt | Term Loan | Cadence Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Debt issued with acquisition		1,300.0
Interest rate							3.50%
Completed Technology | H. P. Acthar Gel | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Discount rate used to value acquired intangible assets	14.50%
Completed Technology | Ofirmev | Cadence Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Discount rate used to value acquired intangible assets		13.00%
Customer Relationships | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Discount rate used to value acquired intangible assets	10.00%
Trademarks | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Discount rate used to value acquired intangible assets	10.00%
Cost of Sales | Questcor and Cadence Pharmaceuticals
Business Acquisition [Line Items]
Cost of sales, inventory step-up			1.1	35.2	1.1	4.4
Accounts Payable | Licensing Agreements | Ofirmev | Cadence Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Accrued milestone payments				$ 10.0		$ 10.0