Acquisitions and License Agreements (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended		3 Months Ended
	Aug. 14, 2014	Mar. 19, 2014	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]
Total consideration		1,329.2
Cash received per share (in usd per share)		$ 14.00
Questcor and Cadence Pharmaceuticals
Business Acquisition [Line Items]
Cost of sales, inventory step-up			30.8
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
Accrued milestone payments			10.0
Royalties paid			10.1
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%
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			0.96%
Secured Debt | Term Loan
Business Acquisition [Line Items]
Interest rate			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%
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%
Specialty Pharmaceuticals [Member] | Completed Technology | Ofirmev | Cadence Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Discount rate used to value acquired intangible assets		13.00%