Acquisitions and License Agreements (Narrative) (Details)				3 Months Ended		9 Months Ended
	Apr. 16, 2015 USD ($)	Aug. 14, 2014 USD ($) pharmacy_indications $ / shares shares	Mar. 19, 2014 USD ($) $ / shares	Jun. 26, 2015 USD ($)	Jun. 27, 2014 USD ($)	Jun. 26, 2015 USD ($)	Jun. 27, 2014 USD ($)
Ikaria, Inc.
Business Acquisition [Line Items]
Consideration Transferred	$ 2,300,000,000
Acquired debt	1,100,000,000
Cash paid with acquisition	$ 1,200,000,000
Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Consideration Transferred		$ 5,900,000,000
Cash received per share (in usd per share) | $ / shares		$ 30.00
Mallinckrodt shares issued per Questcor share (in shares) | shares		0.897
Total Mallinckrodt shares issued with Questcor acquisition (in shares) | shares		57,000,000
Cadence Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Consideration Transferred			$ 1,300,000,000
Cash received per share (in usd per share) | $ / shares			$ 14.00
H. P. Acthar Gel | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Number or FDA approved indications | pharmacy_indications		19
Synacthen | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Milestone Payments				$ 25,000,000
Milestone Payment, Maximum Amount						$ 190,000,000
In-process Research and Development | Terlipressin | Ikaria, Inc.
Business Acquisition [Line Items]
Discount rate used to value acquired intangible assets	17.00%
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]
Milestone Payments						10,000,000
Milestone Payment, Maximum Amount						25,000,000
Royalties paid				19,500,000	$ 5,400,000	34,600,000	$ 5,400,000
Completed Technology | Inomax | Ikaria, Inc.
Business Acquisition [Line Items]
Discount rate used to value acquired intangible assets	14.50%
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%
Trademarks | Ikaria, Inc.
Business Acquisition [Line Items]
Discount rate used to value acquired intangible assets	14.50%
Trademarks | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Discount rate used to value acquired intangible assets		10.00%
Customer Relationships | 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				4,000,000	$ 9,500,000	39,200,000	$ 10,600,000
Receivable Securitization | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Cash paid with acquisition		$ 150,000,000
Unsecured Debt | Ikaria, Inc.
Business Acquisition [Line Items]
Debt issued with acquisition	$ 1,400,000,000
Unsecured Debt | 2020 Notes | Ikaria, Inc.
Business Acquisition [Line Items]
Interest rate	4.875%
Unsecured Debt | 2025 Notes | Ikaria, Inc.
Business Acquisition [Line Items]
Interest rate	5.50%
Unsecured Debt | Revolving Credit Facility | Ikaria, Inc.
Business Acquisition [Line Items]
Interest rate	3.00%
Revolving Credit Facility
Business Acquisition [Line Items]
Borrowings outstanding, credit facilities				$ 0		$ 0
Interest rate				2.77%		2.77%
Revolving Credit Facility | Ikaria, Inc.
Business Acquisition [Line Items]
Borrowings outstanding, credit facilities	$ 240,000,000
Senior Notes | 5.75% Senior Notes | Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Debt issued with acquisition		900,000,000
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		$ 700,000,000
Interest rate		3.50%
Secured Debt | Receivable Securitization
Business Acquisition [Line Items]
Borrowings outstanding, credit facilities				$ 153,000,000		$ 153,000,000
Interest rate				0.9866%		0.9866%
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			$ 1,300,000,000
Interest rate			3.50%