Mallinckrodt (MNKTQ) 10-K 27 Feb 18 2017 FY Annual report Financial data

Document And Entity Information

Document And Entity Information [Abstract] - USD ($) $ in Millions	12 Months Ended
	Dec. 29, 2017	Feb. 23, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Entity Common Stock, Shares Outstanding		86,350,357
Entity Registrant Name	Mallinckrodt plc
Entity Central Index Key	1,567,892
Trading Symbol	MNK
Current Fiscal Year End Date	--12-29
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 29, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 4,352.8

Consolidated and Combined State

Consolidated and Combined Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended																	12 Months Ended
	Dec. 29, 2017		Sep. 29, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 30, 2016	Sep. 30, 2016		Jun. 24, 2016		Mar. 25, 2016		Dec. 25, 2015		Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Net sales	$ 792.3		$ 793.9		$ 824.5		$ 810.9		$ 829.9	$ 887.2		$ 866.6		$ 815.8		$ 811.2		$ 3,221.6	$ 3,380.8	$ 2,923.1
Cost of sales									384.1							360.3		1,565.3	1,525.8	1,300.2
Gross profit	421		400.6		416.1		418.6		445.8	490.2		488.8		425.1		450.9		1,656.3	1,855	1,622.9
Selling, general and administrative expenses									368.3							223.3		920.9	925.3	1,023.8
Research and development expenses									66.2							61.4		277.3	262.2	203.3
Separation costs									0									0	0	0
Other Asset Impairment Charges									214.3							0		63.7	16.9	0
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal									0									(56.9)	0	(3)
Restructuring charges, net									3.8							4.1		31.2	33.3	45
Non-restructuring impairment charges									214.3									63.7	16.9	0
Gain on divestiture and license									0									(56.9)	0	(3)
Operating income (loss)									(206.8)							(162.1)		420.1	617.3	353.8
Interest expense									(91.3)							(97.8)		(369.1)	(384.6)	(255.6)
Interest income									0.5							0.2		4.6	1.3	1
Other income (expense), net									(0.9)							2		6	(0.6)	8.1
Income (loss) from continuing operations before income taxes									(298.5)							66.5		61.6	233.4	107.3
Income Tax Expense (Benefit)									(121.7)							(37.3)		(1,709.6)	(255.6)	(129.3)
Income (loss) from continuing operations	1,607.4		64.3		70.6		28.9		(176.8)	110		176.7		98.5		103.8		1,771.2	489	236.6
Income from discontinued operations, net of tax expense of $5.4, $43.5, $47.9 and $15.3	1.3		(0.6)		(7.8)		370.3		23.6	5		22.6		19.8		107.3		363.2	154.7	88.1
Net income (loss)	$ 1,608.7		$ 63.7		$ 62.8		$ 399.2		$ (153.2)	$ 115		$ 199.3		$ 118.3		$ 211.1		$ 2,134.4	$ 643.7	$ 324.7
Basic earnings per share (Note 9):
Income (Loss) from Continuing Operations, Per Basic Share	$ 17.43	[1]	$ 0.66	[1]	$ 0.72	[1]	$ 0.28	[1]	$ (1.67)	$ 1.02	[1]	$ 1.63	[1]	$ 0.89	[1]	$ 0.90	[1]	$ 18.13	$ 4.42	$ 2.03
Income (Loss) from Discontinued Operations, Per Basic Share									0.22							0.93		3.72	1.40	0.75
Net income (in usd per share)									$ (1.45)							$ 1.83		$ 21.85	$ 5.82	$ 2.78
Weighted Average Number of Shares Outstanding, Basic									105.7							115.4		97.7	110.6	115.8
Diluted earnings per share (Note 9):
Income (Loss) from Continuing Operations, Per Diluted Share	$ 17.40	[1]	$ 0.66	[1]	$ 0.72	[1]	$ 0.28	[1]	$ (1.67)	$ 1.01	[1]	$ 1.62	[1]	$ 0.88	[1]	$ 0.89	[1]	$ 18.09	$ 4.39	$ 2
Income (Loss) from Discontinued Operations, Per Diluted Share									0.22							0.92		3.71	1.39	0.75
Net income (in usd per share)									$ (1.45)							$ 1.82		$ 21.80	$ 5.77	$ 2.75
Diluted weighted-average shares oustanding (in shares)									105.7							116.3		97.9	111.5	117.2
[1]	Quarterly and annual computations are prepared independently. Therefore, the sum of each quarter may not necessarily total the fiscal period amounts noted elsewhere within this Annual Report on Form 10-K.

Consolidated and Combined Stat3

Consolidated and Combined Statements of Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Income Statement [Abstract]
Tax (benefit) expense on income (loss) from discontinued operations	$ 15.3	$ 5.4	$ 43.5	$ 47.9

Consolidated and Combined Stat4

Consolidated and Combined Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended									12 Months Ended
	Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jun. 24, 2016	Mar. 25, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Net income (loss)	$ 1,608.7	$ 63.7	$ 62.8	$ 399.2	$ (153.2)	$ 115	$ 199.3	$ 118.3	$ 211.1	$ 2,134.4	$ 643.7	$ 324.7
Other comprehensive income (loss), net of tax
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax					0					1.5	0	0
Currency translation adjustments					(21.1)					11.3	(58.6)	(70.8)
Unrecognized gain on derivatives, net of tax expense of $0.3, $0.2, $0.2 and $-					0.2					1	0.5	0.4
Unrecognized gain (loss) on benefit plans, net of tax expense (benefit) of $30.8, ($15.0), ($2.1) and ($19.3)					34					45.8	(28.4)	5.6
Total other comprehensive income (loss), net of tax					13.1					59.6	(86.5)	(64.8)
Comprehensive income (loss)					$ (140.1)					$ 2,194	$ 557.2	$ 259.9

Consolidated and Combined Stat5

Consolidated and Combined Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Statement of Comprehensive Income [Abstract]
Unrecognized loss on derivatives, tax	$ 0	$ (0.3)	$ (0.2)	$ (0.2)
Unrecognized gain (loss) on benefit plans, tax	$ 19.3	$ (30.8)	$ 15	$ 2.1

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 29, 2017	Dec. 30, 2016
Current Assets:
Cash and cash equivalents	$ 1,260.9	$ 342
Accounts receivable, less allowance for doubtful accounts of $3.9 and $4.0	445.8	431
Inventories	340.4	350.7
Prepaid expenses and other current assets	84.1	131.9
Notes, Loans and Financing Receivable, Net, Current	154	0
Current assets held for sale	0	310.9
Total current assets	2,285.2	1,566.5
Property, plant and equipment, net	966.8	881.5
Goodwill	3,482.7	3,498.1
Intangible assets, net	8,375	9,000.5
Other assets	171.2	259.7
Total Assets	15,280.9	15,206.3
Current Liabilities:
Current maturities of long-term debt	313.7	271.2
Accounts payable	113.3	112.1
Accrued payroll and payroll-related costs	98.5	76.1
Interest Payable, Current	57	68.7
Taxes Payable, Current	15.8	101.7
Accrued and other current liabilities	452.1	557.1
Current liabilities held for sale	0	120.3
Total current liabilities	1,050.4	1,307.2
Long-term debt	6,420.9	5,880.8
Pension and postretirement benefits	67.1	136.4
Environmental liabilities	73.2	73
Deferred income taxes	689	2,398.1
Accrued Income Taxes, Noncurrent	94.1	70.4
Other liabilities	364.2	356.1
Total Liabilities	8,758.9	10,222
Shareholders' Equity:
Preferred shares, $0.20 par value, 500,000,000 authorized; none issued or outstanding	0	0
Ordinary A shares, €1.00 par value, 40,000 authorized; none issued or outstanding	0	0
Ordinary shares, $0.20 par value, 500,000,000 authorized; 92,196,662 and 118,182,944 issued; 86,336,232 and 104,667,545 outstanding	18.4	23.6
Ordinary shares held in treasury at cost, 5,860,430 and 13,515,399	(1,564.7)	(919.8)
Additional paid-in capital	5,492.6	5,424
Retained earnings	2,588.6	529
Accumulated other comprehensive income	(12.9)	(72.5)
Total Shareholders' Equity	6,522	4,984.3
Total Liabilities and Shareholders' Equity	$ 15,280.9	$ 15,206.3

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) $ in Millions	Dec. 29, 2017USD ($)$ / sharesshares	Dec. 29, 2017€ / shares	Dec. 30, 2016USD ($)$ / sharesshares	Dec. 30, 2016€ / shares	Sep. 30, 2016USD ($)$ / sharesshares	Sep. 30, 2016€ / shares
Statement of Financial Position [Abstract]
Allowance for doubtful accounts | $	$ 3.9		$ 4		$ 4
Preferred shares, par value (in usd per share) | $ / shares	$ 0.20		$ 0.20		$ 0.20
Preferred shares, shares authorized (in shares)	500,000,000		500,000,000		500,000,000
Preferred shares, shares issued (in shares)	0		0		0
Preferred shares, shares outstanding (in shares)	0		0		0
Ordinary A shares, par value (in eur per share) | € / shares		€ 1		€ 1		€ 1
Ordinary A shares, shares authorized (in shares)	40,000		40,000		40,000
Ordinary A shares, shares issued (in shares)	0		0		0
Ordinary A shares, shares outstanding (in shares)	0		0		0
Ordinary shares, par value (in usd per share) | $ / shares	$ 0.20		$ 0.20		$ 0.20
Ordinary shares, shares authorized (in shares)	500,000,000		500,000,000		500,000,000
Ordinary shares, shares issued (in shares)	92,196,662		118,182,944		118,137,297
Ordinary shares, shares outstanding (in shares)	86,336,232		104,667,545		107,167,693
Ordinary shares held in treasury (in shares)	5,860,430		13,515,399		11,000,000

Consolidated and Combined Stat8

Consolidated and Combined Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Restricted Cash and Investments, Current	$ 0.1	$ 0	$ 0.1	$ 47.7
Restricted Cash and Investments, Noncurrent	19	18.2	19	19
Cash and Cash Equivalents, Including Restricted Cash	361.1	1,279.1	299.6	432.6
Cash and cash equivalents	342	1,260.9	280.5	365.9
Cash Flows from Operating Activities:
Net income (loss)	(153.2)	2,134.4	643.7	324.7
Adjustments to reconcile net cash provided by operating activities:
Depreciation and amortization	203.2	808.3	834.5	672.5
Share-based compensation	11	59.2	42.9	117
Deferred income taxes	(204.3)	(1,744.1)	(432.9)	(191.6)
Non-cash impairment charges	214.3	63.7	16.9	0
Inventory provisions	8.5	34.1	29.2	0
Gain (Loss) on Disposition of Business	0	(418.1)	(95.3)	0
Other non-cash items	(9.2)	(21.4)	29.6	(25.5)
Changes in assets and liabilities, net of the effects of acquisitions:
Accounts receivable, net	36.5	(16.2)	31.2	0.7
Inventories	(26.3)	(23.6)	(17.3)	61.3
Accounts payable	5.4	(25.8)	(9.7)	20.4
Income taxes	0.6	(34.2)	93.9	30.2
Other	109.1	(89)	17.9	(79.2)
Net cash from operating activities	195.6	727.3	1,184.6	930.5
Cash Flows from Investing Activities:
Capital expenditures	(65.2)	(186.1)	(182.9)	(148)
Acquisitions and intangibles, net of cash acquired	(1.8)	(76.3)	(245.4)	(2,154.7)
Proceeds from Divestiture of Businesses, Net of Cash Divested	0	576.9	266.7	0
Other	(10.2)	3.9	6	3
Net cash from investing activities	(77.2)	318.4	(155.6)	(2,299.7)
Cash Flows from Financing Activities:
Issuance of external debt	190	1,465	98.3	3,010
Repayment of external debt and capital leases	(86.7)	(917.2)	(568.6)	(1,848.4)
Debt financing costs	0	(12.7)	(0.1)	(39.9)
Proceeds from exercise of share options	0.4	4.1	14	34.4
Repurchase of shares	(158.8)	(651.7)	(652.9)	(92.2)
Other	1.2	(17.7)	(53)	(28.1)
Net cash from financing activities	(53.9)	(130.2)	(1,162.3)	1,035.8
Effect of currency rate changes on cash	(3)	2.5	0.3	(11.6)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	61.5	918	(133)	(345)
Supplemental Disclosures of Cash Flow Information:
Cash paid for interest	95.4	339.1	332.4	200.5
Cash paid for income taxes, net	$ 95.6	$ 73.4	$ 165.4	$ 123.8

Consolidated and Combined Stat9

Consolidated and Combined Statement of Changes in Shareholders' Equity Statement - USD ($) $ in Millions	Total	Ordinary Shares	Treasury Shares	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income
Beginning balance, shares at Sep. 26, 2014		116,200,000	200,000
Beginning balance, value at Sep. 26, 2014	$ 4,958	$ 23.2	$ (17.5)	$ 5,172.4	$ (285.8)	$ 65.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	324.7				324.7
Currency translation adjustments	(70.8)					(70.8)
Change in derivatives, net of tax	0.4					0.4
Minimum pension liability, net of tax	5.6					5.6
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax	0
Treasury Stock, Shares, Retired		(1,200,000)
Stock Repurchased and Retired During Period, Value	$ 0	$ (0.2)		(0.2)
Share options exercised, shares	1,132,778	1,200,000
Share options exercised, value	$ 34.4	$ 0.2		34.2
Vesting of restricted shares, shares		1,300,000
Vesting of restricted shares, value	0	$ (0.3)		(0.3)
Adjustments to Additional Paid in Capital, Income Tax Deficiency from Share-based Compensation	34.1			34.1
Treasury Stock, Shares, Acquired			1,000,000
Treasury Stock, Value, Acquired, Cost Method	(92.2)		$ (92.2)
Share-based compensation	117			117
Ending balance, shares at Sep. 25, 2015		117,500,000	1,200,000
Ending balance, value at Sep. 25, 2015	5,311.2	$ 23.5	$ (109.7)	5,357.6	38.9	0.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	643.7				643.7
Currency translation adjustments	(58.6)					(58.6)
Change in derivatives, net of tax	0.5					0.5
Minimum pension liability, net of tax	(28.4)					(28.4)
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax	$ 0
Share options exercised, shares	413,830	400,000
Share options exercised, value	$ 14	$ 0.1		13.9
Vesting of restricted shares, shares		200,000
Vesting of restricted shares, value	0	$ 0		0
Adjustments to Additional Paid in Capital, Income Tax Deficiency from Share-based Compensation	$ (1.7)			(1.7)
Treasury Stock, Shares, Acquired	9,800,000
Treasury Stock, Value, Acquired, Cost Method	$ (652.9)
Share-based compensation	42.9			42.9
Ending balance, shares at Sep. 30, 2016		118,100,000	11,000,000
Ending balance, value at Sep. 30, 2016	5,270.7	$ 23.6	$ (762.6)	5,412.7	682.6	(85.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(153.2)				(153.2)
Currency translation adjustments	(21.1)					(21.1)
Change in derivatives, net of tax	0.2					0.2
Minimum pension liability, net of tax	34					34
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax	$ 0
Share options exercised, shares	16,382	100,000
Share options exercised, value	$ 0.4	$ 0		0.4
Vesting of restricted shares, value	0
Adjustments to Additional Paid in Capital, Income Tax Deficiency from Share-based Compensation	$ (0.1)			(0.1)
Treasury Stock, Shares, Acquired	2,500,000
Treasury Stock, Value, Acquired, Cost Method	$ (158.8)		158.8
Share-based compensation	11			11
Stock Issued During Period, Value, Treasury Stock Reissued	(1.2)		$ (1.6)		(0.4)
Ending balance, shares at Dec. 30, 2016		118,200,000	13,500,000
Ending balance, value at Dec. 30, 2016	4,984.3	$ 23.6	$ (919.8)	5,424	529	(72.5)
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(72.1)				(72.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	2,134.4
Currency translation adjustments	11.3					11.3
Change in derivatives, net of tax	1					1
Minimum pension liability, net of tax	45.8					45.8
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax	1.5					1.5
Treasury Stock, Shares, Retired		(26,500,000)
Stock Repurchased and Retired During Period, Value	$ 0	$ (5.3)		(5.3)
Treasury Stock, Shares, Retired			(26,500,000)
Share options exercised, shares	113,605	100,000
Share options exercised, value	$ 4.1	$ 0		4.1
Vesting of restricted shares, shares		400,000
Vesting of restricted shares, value	(0.1)	$ (0.1)		0
Treasury Stock, Shares, Acquired			18,900,000
Treasury Stock, Value, Acquired, Cost Method	(651.7)		$ (651.7)
Share-based compensation	59.2			59.2
Stock Issued During Period, Value, Treasury Stock Reissued	(4.1)		$ (6.8)		(2.7)
Ending balance, shares at Dec. 29, 2017		92,200,000	5,900,000
Ending balance, value at Dec. 29, 2017	$ 6,522	$ 18.4	$ (1,564.7)	$ 5,492.6	$ 2,588.6	$ (12.9)

Background and Basis of Present

Background and Basis of Presentation (Notes)	12 Months Ended
	Dec. 29, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Background and Basis of Presentation	Background Mallinckrodt plc and its subsidiaries (collectively, "Mallinckrodt" or "the Company"), is a global business that develops, manufactures, markets and distributes specialty pharmaceutical products and therapies. As of December 29, 2017, areas of focus include autoimmune and rare diseases in specialty areas like neurology, rheumatology, nephrology, pulmonology and ophthalmology; immunotherapy and neonatal respiratory critical care therapies; and analgesics. Our core strengths include the acquisition and management of highly regulated raw materials and specialized chemistry, formulation and manufacturing capabilities. Our business is operated in two reportable segments, which are further described below: • Specialty Brands includes branded medicines; and • Specialty Generics includes specialty generic drugs, active pharmaceutical ingredients ("API") and external manufacturing. In May 2015, the Board of Directors of Mallinckrodt plc approved the migration of the Company’s principal executive offices from Ireland to the United Kingdom. The Company remains incorporated in Ireland and continues to be subject to United States ("U.S.") Securities and Exchange Commission ("SEC") reporting requirements and the applicable corporate governance rules of the New York Stock Exchange. Basis of Presentation The consolidated financial statements have been prepared in U.S. dollars and in accordance with accounting principles generally accepted in the U.S. ("GAAP"). The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amount of assets and liabilities, disclosure of contingent assets and liabilities and the reported amounts of revenues and expenses. Actual results may differ from those estimates. The consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries and entities in which they own or control more than 50% of the voting shares, or have the ability to control through similar rights. All intercompany balances and transactions have been eliminated in consolidation and all normal recurring adjustments necessary for a fair presentation have been included in the results reported. The results of entities disposed of are included in the consolidated financial statements up to the date of disposal and, where appropriate, these operations have been reflected as discontinued operations. Divestitures of product lines not meeting the criteria for discontinued operations have been reflected in operating income. As such, when the Company completed the sale of its Nuclear Imaging business and contrast media and delivery systems ("CMDS") businesses on January 27, 2017 and November 27, 2015, respectively, prior year balances were recast to present the financial results of these business as discontinued operations. Beginning in the first quarter of fiscal year 2016, the Company revised the presentation of certain medical affairs costs to better align with industry practice, which were previously included in selling, general and administrative ("SG&A") expenses and are now included in research and development ("R&D") expenses. As a result, $56.4 million of expenses previously included in SG&A for the fiscal year ended September 25, 2015 have been classified as R&D expenses to conform to this change. No other financial statement line items were impacted by this change in classification.

Transition Period (Notes)

Transition Period (Notes)	12 Months Ended
	Dec. 29, 2017
Transition Period [Text Block]	2. Transition Period The Company is presenting audited financial statements for the three month period ended December 30, 2016. The following tables provide certain unaudited comparative financial information for the same period of the prior year. Consolidated Statements of Income Three Months Ended (unaudited) Net sales $ 829.9 $ 811.2 Cost of sales 384.1 360.3 Gross profit 445.8 450.9 Selling, general and administrative expenses 368.3 223.3 Research and development expenses 66.2 61.4 Restructuring charges, net 3.8 4.1 Non-restructuring impairment charges 214.3 — Operating (loss) income (206.8 ) 162.1 Interest expense (91.3 ) (97.8 ) Interest income 0.5 0.2 Other (expense) income, net (0.9 ) 2.0 (Loss) income from continuing operations before income taxes (298.5 ) 66.5 Benefit from income taxes (121.7 ) (37.3 ) (Loss) income from continuing operations (176.8 ) 103.8 Income from discontinued operations 23.6 107.3 Net (loss) income $ (153.2 ) $ 211.1 Basic earnings per share (Note 9): (Loss) income from continuing operations $ (1.67 ) $ 0.90 Income from discontinued operations, net of income taxes 0.22 0.93 Net (loss) income $ (1.45 ) $ 1.83 Basic weighted-average shares outstanding 105.7 115.4 Diluted earnings per share (Note 9): (Loss) income from continuing operations $ (1.67 ) $ 0.89 Income from discontinued operations, net of income taxes 0.22 0.92 Net (loss) income $ (1.45 ) $ 1.82 Diluted weighted-average shares outstanding 105.7 116.3 Consolidated Statements of Cash Flows Three Months Ended December 30, 2016 (unaudited) December 25, 2015 Cash Flows From Operating Activities: Net (loss) income $ (153.2 ) $ 211.1 Adjustments to reconcile net cash provided by operating activities: Depreciation and amortization 203.2 206.0 Share-based compensation 11.0 8.5 Deferred income taxes (204.3 ) (108.9 ) Non-cash impairment charges 214.3 — Inventory provisions 8.5 1.2 Gain on disposal of discontinued operations — (97.0 ) Other non-cash items (9.2 ) 2.9 Changes in assets and liabilities, net of the effects of acquisitions: Accounts receivable, net 36.5 68.4 Inventories (26.3 ) (14.5 ) Accounts payable 5.4 (13.0 ) Income taxes 0.6 82.3 Other 109.1 (35.6 ) Net cash from operating activities 195.6 311.4 Cash Flows From Investing Activities: Capital expenditures (65.2 ) (49.0 ) Acquisitions and intangibles, net of cash acquired (1.8 ) — Proceeds from disposal of discontinued operations, net of cash — 263.7 Other (10.2 ) 0.7 Net cash from investing activities (77.2 ) 215.4 Cash Flows From Financing Activities: Issuance of external debt 190.0 62.0 Repayment of external debt and capital leases (86.7 ) (129.6 ) Debt financing costs — (0.1 ) Proceeds from exercise of share options 0.4 3.6 Repurchase of shares (158.8 ) (275.4 ) Other 1.2 (30.0 ) Net cash from financing activities (53.9 ) (369.5 ) Effect of currency rate changes on cash (3.0 ) (1.5 ) Net change in cash, cash equivalents and restricted cash 61.5 155.8 Cash, cash equivalents and restricted cash at beginning of period 299.6 432.6 Cash, cash equivalents and restricted cash at end of period $ 361.1 $ 588.4 Cash and cash equivalents at end of period $ 342.0 $ 521.9 Restricted cash included in prepaid expenses and other assets at end of period $ 0.1 $ 47.5 Restricted cash included in other long-term assets at end of period $ 19.0 $ 19.0 Cash, cash equivalents and restricted cash at end of period $ 361.1 $ 588.4

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 29, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	3. Summary of Significant Accounting Policies Revenue Recognition The Company recognizes revenue for product sales when title and risk of loss have transferred from the Company to the buyer, which may be upon shipment, delivery to the customer site, consumption of the product by the customer, or over the period in which the customer has access to the product and any related services, based on contract terms or legal requirements in non-U.S. jurisdictions. The Company sells products through independent channels, including directly to retail pharmacies, end user customers and through distributors who resell the products to retail pharmacies, institutions and end user customers. Certain products are sold and distributed directly to hospitals. Chargebacks and rebates are provided to certain distributors and customers for either the difference between the Company's contracted price with a customer and the distributor's invoice price paid to the Company or for contractually agreed discounts. When the Company recognizes net sales, it simultaneously records an adjustment to revenue for estimated chargebacks, rebates, product returns and other sales deductions. These provisions are estimated based upon historical experience, estimated future trends, estimated customer inventory levels, current contracted sales terms with customers, level of utilization of the Company's products and other competitive factors. The Company adjusts these reserves to reflect differences between estimated activity and actual experience. Such adjustments impact the amount of net sales recognized by the Company in the period of adjustment. Taxes collected from customers relating to product sales and remitted to governmental authorities are accounted for on a net basis. Accordingly, such taxes are excluded from both net sales and expenses. Shipping and Handling Costs Shipping costs, which are costs incurred to physically move product from the Company's premises to the customer's premises, are classified as selling, general and administrative expenses. Handling costs, which are costs incurred to store, move and prepare product for shipment, are classified as cost of sales. Shipping costs included in SG&A expenses in continuing operations were as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Shipping and handling costs $ 13.9 $ 12.4 $ 11.6 $ 3.4 Research and Development Internal research and development costs are expensed as incurred. Research and development expenses include salary and benefits, allocated overhead and occupancy costs, clinical trial and related clinical manufacturing costs, contract services, medical affairs and other costs. Upfront and milestone payments made to third parties under license arrangements are expensed as incurred up to the point of regulatory approval of the product. Milestone payments made to third parties upon or subsequent to regulatory approval are capitalized as an intangible asset and amortized to cost of sales over the estimated useful life of the related product. Currency Translation For the Company's non-U.S. subsidiaries that transact in a functional currency other than U.S. dollars, assets and liabilities are translated into U.S. dollars using fiscal year-end exchange rates. Revenues and expenses are translated at the average exchange rates in effect during the related month. The net effect of these translation adjustments is shown in the consolidated financial statements as a component of accumulated other comprehensive income. For subsidiaries operating in highly inflationary environments or where the functional currency is different from the local currency, non-monetary assets and liabilities are translated at the rate of exchange in effect on the date the assets and liabilities were acquired or assumed, while monetary assets and liabilities are translated at fiscal year-end exchange rates. Translation adjustments of these subsidiaries are included in net income. Gains and losses resulting from foreign currency transactions are included in net income. During fiscal 2017 , fiscal 2015 and the three months ended December 30, 2016, the Company had $2.5 million , $31.6 million and $9.0 million of foreign currency gains , respectively, and during fiscal 2016, the Company had $3.6 million of foreign currency losses included within income (loss) from continuing operations. The Company entered into derivative instruments to mitigate the exposure of movements in certain of these foreign currency transactions and recognized losses of $4.1 million , $24.8 million and $8.9 million in fiscal 2017, fiscal 2015 and the three months ended December 30, 2016, and a gain of $0.2 million in fiscal 2016 , respectively, within income (loss) from continuing operations. Cash and Cash Equivalents The Company classifies cash on hand and deposits in banks, including commercial paper, money market accounts and other investments it may hold from time to time, with an original maturity to the Company of three months or less, as cash and cash equivalents. Accounts Receivable and Allowance for Doubtful Accounts Trade accounts receivable are presented net of an allowance for doubtful accounts. The allowance for doubtful accounts reflects an estimate of losses inherent in the Company's accounts receivable portfolio determined on the basis of historical experience, specific allowances for known troubled accounts and other available evidence. Accounts receivable are written off when management determines they are uncollectible. Trade accounts receivable are also presented net of reserves related to chargebacks and rebates payable to customers for whom the Company has trade accounts receivable and the right of offset exists. Inventories Inventories are recorded at the lower of cost or net realizable value, primarily using the first-in, first-out convention. The Company reduces the carrying value of inventories for those items that are potentially excess, obsolete or slow-moving based on changes in customer demand, technology developments or other economic factors. Property, Plant and Equipment Property, plant and equipment are stated at cost. Major renewals and improvements are capitalized, while routine maintenance and repairs are expensed as incurred. Depreciation for property, plant and equipment assets, other than land and construction in process, is generally based upon the following estimated useful lives, using the straight-line method: Buildings 10 to 45 years Leasehold improvements 1 to 20 years Capitalized software 1 to 10 years Machinery and equipment 1 to 20 years The Company capitalizes certain computer software and development costs incurred in connection with developing or obtaining software for internal use. Upon retirement or other disposal of property, plant and equipment, the cost and related amount of accumulated depreciation are eliminated from the asset and accumulated depreciation accounts, respectively. The difference, if any, between the net asset value and the proceeds is included in net income. The Company assesses the recoverability of assets or asset groups using undiscounted cash flows whenever events or circumstances indicate that the carrying value of an asset or asset group may not be recoverable. If an asset or asset group is found to be impaired, the amount recognized for impairment is equal to the difference between the carrying value of the asset or asset group and its fair value. Acquisitions Amounts paid for acquisitions are allocated to the tangible assets acquired and liabilities assumed based on their estimated fair values at the date of acquisition. The Company then allocates the purchase price in excess of net tangible assets acquired to identifiable intangible assets, including purchased R&D. The fair value of identifiable intangible assets is based on detailed valuations. The Company allocates any excess purchase price over the fair value of the net tangible and intangible assets acquired to goodwill. The Company's purchased R&D represents the estimated fair value as of the acquisition date of in-process projects that have not reached technological feasibility. The primary basis for determining technological feasibility of these projects is obtaining regulatory approval. The fair value of in-process research and development ("IPR&D") is determined using the discounted cash flow method. In determining the fair value of IPR&D, the Company considers, among other factors, appraisals, the stage of completion of the projects, the technological feasibility of the projects, whether the projects have an alternative future use and the estimated residual cash flows that could be generated from the various projects and technologies over their respective projected economic lives. The discount rate used includes a rate of return which accounts for the time value of money, as well as risk factors that reflect the economic risk that the cash flows projected may not be realized. The fair value attributable to IPR&D projects at the time of acquisition is capitalized as an indefinite-lived intangible asset and tested annually for impairment until the project is completed or abandoned. Upon completion of the project, the indefinite-lived intangible asset is then accounted for as a finite-lived intangible asset and amortized on a straight-line basis over its estimated useful life. If the project is abandoned, the indefinite-lived intangible asset is charged to expense. Goodwill and Other Intangible Assets Goodwill represents the excess of the purchase price of an acquired entity over the amounts assigned to assets and liabilities assumed in a business combination. The Company tests goodwill for impairment on the first day of the fourth quarter of each fiscal year, or whenever events or changes in circumstances indicate that the carrying value may not be recoverable. The impairment test is comprised of comparing the carrying value of a reporting unit to its estimated fair value. The Company estimates the fair value of a reporting unit through internal analyses and valuation, utilizing an income approach (a level three measurement technique) based on the present value of future cash flows. If the carrying value of a reporting unit exceeds its fair value, the Company will recognize the excess of the carrying value over the fair value as a goodwill impairment loss. Intangible assets acquired in a business combination are recorded at fair value, while intangible assets acquired in other transactions are recorded at cost. Intangible assets with finite useful lives are subsequently amortized, generally using the straight-line method, over the following estimated useful lives of the assets, except for customer relationships which are amortized over the estimated pattern of benefit from these relationships: Completed technology 5 to 25 years License agreements 7 to 30 years Trademarks 13 to 30 years Customer relationships 12 years Amortization expense related to completed technology and certain other intangible assets is included in cost of sales, while amortization expense related to intangible assets that contribute to the Company's ability to sell, market and distribute products is included in SG&A. When a triggering event occurs, the Company evaluates potential impairment of finite-lived intangible assets by first comparing undiscounted cash flows associated with the asset, or the asset group they are part of, to its carrying value. If the carrying value is greater than the undiscounted cash flows, the amount of potential impairment is measured by comparing the fair value of the assets, or the asset group they are part of, with their carrying value. The fair value of the intangible asset, or the asset group they are part of, is estimated using an income approach. If the fair value is less than the carrying value of the intangible asset, or the asset group they are part of, the amount recognized for impairment is equal to the difference between the carrying value of the asset and the fair value of the asset. The Company assesses the remaining useful life and the recoverability of finite-lived intangible assets whenever events or circumstances indicate that the carrying value of an asset may not be recoverable. The Company annually tests the indefinite-lived intangible assets for impairment, or whenever events or changes in circumstances indicate that the carrying value may not be recoverable by either a qualitative or income approach. The Company will compare the fair value of the assets with their carrying value and record an impairment when the carrying value exceeds the fair value. Contingencies The Company is subject to various patent infringement, product liability, government investigations, environmental matters and other legal proceedings in the ordinary course of business. The Company records accruals for contingencies when it is probable that a liability has been incurred and the amount can be reasonably estimated. The Company discounts environmental liabilities using a risk-free rate of return when the obligation is fixed or reasonably determinable. The impact of the discount in the consolidated balance sheets was not material in any period presented. Legal fees, other than those pertaining to environmental and asbestos matters, are expensed as incurred. Insurance recoveries related to potential claims are recognized up to the amount of the recorded liability when coverage is confirmed and the estimated recoveries are probable of payment. Assets and liabilities are not netted for financial statement presentation. Share-Based Compensation The Company recognizes the cost of employee services received in exchange for awards of equity instruments based on the grant-date fair value of those awards. That cost is recognized over the period during which an employee is required to provide service in exchange for the award, the requisite service period (generally the vesting period). Restructuring The Company recognizes charges associated with board approved restructuring programs designed to transform its business and improve its cost structure. Restructuring charges can include severance costs, infrastructure charges, distributor contract cancellations and other items. The Company records restructuring charges based on estimated consolidation plans and accrues for costs when they are probable and reasonably estimable. Income Taxes Deferred tax assets and liabilities are recognized for the expected future tax consequences of events that have been reflected in the consolidated financial statements. Deferred tax assets and liabilities are determined based on the differences between the book and tax bases of assets and liabilities and operating loss carryforwards, using tax rates expected to be in effect for the years in which the differences are expected to reverse. A valuation allowance is provided to reduce net deferred tax assets if, based upon the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. Deferred tax liabilities are also recorded for deferred tax obligations related to installment sale arrangements. The deferral of tax payments to the U.S. Internal Revenue Service ("IRS") are subject to interest, which is accrued and included within interest expense. The Company determines whether it is more likely than not that a tax position will be sustained upon examination. The tax benefit of any tax position that meets the more-likely-than-not recognition threshold is calculated as the largest amount that is more than 50% likely of being realized upon resolution of the uncertainty. To the extent a full benefit is not expected to be realized on the uncertain tax position, an income tax liability is established. Interest and penalties on income tax obligations, associated with uncertain tax positions, are included in the provision for income taxes. The calculation of the Company's tax liabilities involves dealing with uncertainties in the application of complex tax regulations in a multitude of jurisdictions across the Company's global operations. Due to the complexity of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from current estimates of the tax liabilities. If the Company's estimate of tax liabilities proves to be less than the ultimate assessment, an additional charge to expense would result. If payment of these amounts ultimately proves to be less than the recorded amounts, the reversal of the liabilities may result in income tax benefits being recognized in the period when it is determined that the liabilities are no longer necessary. A significant portion of these potential tax liabilities are recorded in other income tax liabilities on the consolidated balance sheets as payment is not expected within one year.

Recently Issued Accounting Stan

Recently Issued Accounting Standards	12 Months Ended
	Dec. 29, 2017
Recently Issued Accounting Pronouncements [Abstract]
Recently Issued Accounting Standards	4. Recently Issued Accounting Standards Adopted The Financial Accounting Standards Board ("FASB") issued Accounting Standard Update ("ASU") 2017-04, "Intangibles - Goodwill and Other: Simplifying the Test for Goodwill Impairment," in January 2017. This update eliminates the two step test utilized in goodwill impairment testing, and requires the goodwill impairment test to be performed by comparing the fair value of a reporting unit with its carrying amount. An impairment charge should be recognized for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The Company early adopted this standard in fiscal 2017, which did not have a material impact to the consolidated financial statements. The Company will apply this standard to prospective goodwill impairment tests. The FASB issued ASU 2016-16, "Income Taxes: Intra-Entity Transfers of Assets Other Than Inventory," in October 2016. This update simplifies the practice in how income tax consequences of an intra-entity transfer of an asset other than inventory should be recognized. Upon adoption, the entity must recognize such income tax consequences when the intra-entity transfer occurs rather than waiting until such time as the asset has been sold to an outside party. The Company early adopted this standard in fiscal 2017, which resulted in a $75.0 million decrease to beginning retained earnings with an offsetting decrease of $67.2 million to other assets and a $7.8 million decrease to prepaid expenses on the consolidated balance sheet. The prior periods were not restated. The FASB issued ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” in August 2016 and ASU 2016-18 "Statement of Cash Flows (Topic 230): Restricted Cash," in November 2016. These updates provide guidance for nine targeted clarifications with respect to how cash receipts and cash payments are classified in the statements of cash flows, with the objective of reducing diversity in practice. The Company early adopted these standards in fiscal 2017 and revised the prior year statement of cash flow. The adoption of ASU 2016-18, regarding presentation of restricted cash, increased the net cash used in investing activities during fiscal 2016 and 2015 by $47.3 million and $3.1 million , respectively. The adoption of ASU 2016-15, regarding the other targeted clarifications, did not result in any material changes to the consolidated financial statements. The FASB issued ASU 2016-09, "Stock Compensation," in March 2016. This update simplifies several aspects of the accounting for share-based payment award transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification of certain tax effects within the statement of cash flows. Upon adoption, the entity must recognize the incremental income tax expense or benefit related to share option exercises and restricted share unit vesting in the statement of income, whereas these tax effects are presently recognized directly in shareholders' equity. In addition, the incremental tax benefit associated with these events will be classified as a cash inflow from operating activity as compared with a financing activity, as required under current guidance. The Company adopted this guidance in fiscal 2017, which resulted in a $2.9 million increase to beginning retained earnings to recognize net operating loss carryforwards, net of a valuation allowance, attributable to excess tax benefits on stock compensation that had not been previously recognized in additional paid-in capital. The FASB issued ASU 2015-17, "Balance Sheet Reclassification of Deferred Taxes," in November 2015. This update requires all deferred tax assets and liabilities, along with any related valuation allowance, to be classified as noncurrent on the consolidated balance sheets. Each jurisdiction will now only have one net noncurrent deferred tax asset or liability. The Company elected to early adopt this guidance as of September 30, 2016 on a prospective basis. As such, the Company reclassified $122.6 million of current deferred income taxes to noncurrent as of September 30, 2016. The FASB issued ASU 2015-16, "Simplifying the Accounting for Measurement-Period Adjustments," in September 2015. This update requires an acquirer to recognize adjustments to the provisional amounts that are identified during the measurement period in the reporting period in which the adjusting amounts are determined. The amendments in this update require an entity to present separately on the face of the income statement or disclose in the notes the portion of the amount recorded in current period earnings by line item that would have been recorded in previous reporting periods if the adjustment to the provisional amounts had been recognized as of the acquisition date. The Company adopted this standard in fiscal 2017, which did not have a material impact to the consolidated financial statements. The FASB issued ASU 2015-11, "Simplifying the Measurement of Inventory," in July 2015. The issuance of ASU 2015-11 is part of the FASB's initiative to more closely align the measurement of inventory between GAAP and International Financial Reporting Standards ("IFRS"). Under the new guidance, inventory must be measured at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The Company adopted this standard in fiscal 2017, which did not have a material impact to the consolidated financial statements. Not Yet Adopted The FASB issued ASU 2017-12, "Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities" in August 2017. This update simplifies the application of hedge accounting and enhances the economics of the entity’s risk management activities in its financial statements. The update amends the guidance on designation and measurement for qualifying hedging relationships requiring the application of a modified retrospective approach on the date of adoption. This guidance is effective for the Company in the first quarter of fiscal 2019. The Company is assessing the impact of this guidance on its consolidated financial statements. The FASB issued ASU 2017-09, "Compensation - Stock Compensation: Scope of Modification Accounting," in May 2017. Under the new guidance, the effects of a modification should be accounted for unless all of the following are met: (1) the fair value or calculated intrinsic value of the modified award is the same as the fair value of the original award immediately before the original award is modified; (2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified; and (3) the classification of the modified award as an equity instrument or a liability instrument is the same as the classification of the original award immediately before the original award is modified. The amendments should be applied prospectively to an award modified on or after the adoption date. This guidance is effective for the Company in the first quarter of fiscal 2018. The Company expects the impact of this guidance to be immaterial to the consolidated financial statements upon adoption. The FASB issued ASU 2017-07, "Compensation - Retirement Benefits: Improving the Presentation of Net Periodic Pension Cost and Net Periodic Post Retirement Benefit Cost," in March 2017. This update requires that the service cost component be disaggregated from the other components of net benefit cost. Service cost should be reported in the same line item or items as other compensation costs arising from services rendered by pertinent employees during the period. The other components of net benefit cost should be presented in the income statement separately from the service cost component and outside a subtotal of income from operations, if one is presented. This guidance is effective for the Company in the first quarter of fiscal 2018. The Company expects the impact of this guidance to be immaterial to the consolidated financial statements upon adoption. The FASB issued ASU 2017-01, "Business Combinations (Topic 805): Clarifying the Definition of a Business," in January 2017. This update provides a screen to determine whether or not a set of assets is a business. The screen requires that when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set of assets is not a business. If the screen is not met, the amendments in this update (1) require that to be considered a business, a set of assets must include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create output and (2) remove the evaluation of whether a market participant could replace missing elements. This guidance is effective for the Company in the first quarter of fiscal 2018. The Company does not anticipate a significant impact upon adoption. The FASB issued ASU 2016-02, "Leases," in February 2016. This update was issued to increase transparency and comparability among organizations by recognizing all lease transactions (with terms in excess of 12 months) on the balance sheet as a lease liability and a right-of-use asset (as defined). This guidance is effective for the Company in the first quarter of fiscal 2019. Upon adoption, the lessee will apply the new standard using a modified retrospective approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. The modified retrospective approach would not require any transition accounting for leases that expired before the earliest comparative period presented. The Company is currently identifying all lease arrangements and will assess the potential impact of this guidance. At this time, the Company does not anticipate a significant impact upon adoption. However, identification of further lease or embedded lease arrangements may identify a more significant impact. The FASB issued ASU 2014-09, "Revenue from Contracts with Customers," in May 2014. The issuance of ASU 2014-09 and International Financial Reporting Standards ("IFRS") 15, "Revenue from Contracts with Customers," completes the joint effort by FASB and the International Accounting Standards Board to clarify the principles for recognizing revenue and develop a common revenue standard for GAAP and IFRS. Under the new guidance, an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services, applying the following steps: (1) identify the contract(s) with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies a performance obligation. The guidance is effective for the Company in the first quarter of fiscal year 2018 (following the change in fiscal year). The FASB subsequently issued additional ASUs to clarify the guidance of ASU 2014-09. The ASUs issued include ASU 2016-08, "Revenue from Contracts with Customers;" ASU 2016-10 "Revenue from Contracts with Customers, Identifying Performance Obligations and Licensing;" and ASU 2016-12, "Narrow-Scope Improvements and Practical Expedients." The Company has substantially completed its assessment of its customer arrangements for which the Company currently recognizes revenues and does not anticipate a material impact upon adoption. The Company will utilize the modified retrospective transition approach of adopting the ASU. Upon adoption, the Company will recognize the cumulative effect of adopting this guidance as an adjustment to beginning retained earnings, the impact of which is not expected to be material. The prior periods will not be restated.

Discontinued Operations and Div

Discontinued Operations and Divestitures	12 Months Ended
	Dec. 29, 2017
Discontinued Operations [Abstract]
Discontinued Operations and Divestitures	5. Discontinued Operations and Divestitures Discontinued Operations Nuclear Imaging: On January 27, 2017, the Company completed the sale of its Nuclear Imaging business to IBA Molecular ("IBAM") for approximately $690.0 million before tax impacts, including up-front considerations of approximately $574.0 million , up to $77.0 million of contingent considerations and the assumption of certain liabilities. The Company recorded a pre-tax gain on the sale of the business of $362.8 million during fiscal 2017, which excluded any potential proceeds from the contingent consideration. The following table summarizes the financial results of the Nuclear Imaging business for fiscal years 2017, 2016 and 2015 and the three months ended December 30, 2016 as presented in the consolidated statements of income: Fiscal Year Ended Three Months Ended Major line items constituting income from discontinued operations December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Net sales $ 31.6 $ 418.6 $ 423.8 $ 99.4 Cost of sales 15.6 216.6 193.1 44.7 Selling, general and administrative 7.8 83.7 89.6 16.4 Restructuring charges, net — 2.3 (4.6 ) — Other (0.2 ) 5.7 37.7 0.2 Income from discontinued operations 8.4 110.3 108.0 38.1 Gain on disposal of discontinued operations 362.8 — — — Income from discontinued operations, before income taxes 371.2 110.3 108.0 38.1 Income tax expense 5.2 49.0 36.4 15.3 Income from discontinued operations, net of tax $ 366.0 $ 61.3 $ 71.6 $ 22.8 The fiscal 2017 income tax expense of $0.9 million was associated with the $362.8 million gain on divestiture and a $4.3 million income tax expense was associated with the $8.4 million income from discontinued operations. The tax impact of the gain recognized on divestiture was favorably impacted by a benefit from permanently deductible items. The income tax expense of $4.3 million was impacted by tax expense of $0.8 million associated with the rate difference between United Kingdom ("U.K.") and Non-U.K. jurisdictions, $3.3 million of tax expense associated with accrued income tax liabilities and uncertain tax positions, and $0.2 million of tax expense associated with permanently nondeductible, nontaxable, and other items. The fiscal 2016 income tax expense of $49.0 million was impacted by tax expense of $11.7 million associated with the rate difference between U.K. and Non-U.K. jurisdictions, $14.4 million of tax expense associated with accrued income tax liabilities and uncertain tax positions, and $0.9 million of tax expense associated with permanently nondeductible, nontaxable, and other items. The fiscal 2015 income tax expense of $36.4 million was impacted by $14.3 million of tax expense associated with the rate difference between U.K. and Non-U.K. jurisdictions and $0.4 million of tax expense associated with permanently nondeductible, nontaxable, and other items. The income tax expense for the three months ended December 30, 2016 of $15.3 million was impacted by tax expense of $4.4 million associated with the rate difference between U.K. and Non-U.K. jurisdictions, $3.3 million of tax expense associated with accrued income tax liabilities and uncertain tax positions, and $0.1 million of tax expense associated with permanently nondeductible, nontaxable, and other items. Fiscal 2017 reflects $0.2 million of Non-U.K. current income tax benefit, and $5.4 million of Non-U.K. deferred income tax expense. Fiscal 2016 reflects $0.1 million of U.K. current income tax expense, $52.5 million of Non-U.K. current income tax expense, and $3.6 million of Non-U.K. deferred income tax benefit. Fiscal 2015 reflects $0.1 million of U.K. current income tax expense, $27.8 million of Non-U.K. current income tax expense, and $8.6 million of Non-U.K. deferred income tax expense. The three months ended December 30, 2016 reflects $15.8 million of Non-U.K. current income tax expense and $0.5 million of Non-U.K. deferred income tax benefit. The following table summarizes the assets and liabilities of the Nuclear Imaging business that are classified as held for sale on the consolidated balance sheets at the end of each period: December 29, 2017 December 30, 2016 Carrying amounts of major classes of assets included as part of discontinued operations Accounts receivable $ — $ 49.6 Inventories — 20.0 Property, plant and equipment, net — 188.7 Other current and non-current assets — 52.6 Total assets classified as held for sale in the balance sheet $ — $ 310.9 Carrying amounts of major classes of liabilities included as part of discontinued operations Accounts payable $ — $ 19.7 Other current and non-current liabilities — 100.6 Total liabilities classified as held for sale in the balance sheet $ — $ 120.3 The following table summarizes significant cash and non-cash transactions of the Nuclear Imaging business that are included within the consolidated statements of cash flows for the fiscal years 2017, 2016 and 2015 and the three months ended December 30, 2016: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Depreciation $ — $ 20.9 $ 13.1 $ — Capital expenditures 0.3 9.7 7.6 2.0 All other notes to the consolidated financial statements that were impacted by this discontinued operation have been reclassified accordingly. CMDS: On November 27, 2015, the Company completed the sale of the CMDS business to Guerbet S.A. ("Guerbet") for cash consideration of approximately $270.0 million . Subsequent to the sale of the CMDS business, the Company continues to supply certain products under a supply agreement with Guerbet. The following table summarizes the financial results of the CMDS business for fiscal 2017, 2016 and 2015 and the three months ended December 30, 2016 as presented in the consolidated statements of income: Fiscal Year Ended Three Months Ended Major line items constituting (loss) income from discontinued operations December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Net sales $ — $ 61.0 $ 413.8 $ — Cost of sales — 46.9 306.4 — Selling, general and administrative — 20.3 97.5 — Restructuring charges, net — — 0.3 — Other — 1.2 4.7 — (Loss) income from discontinued operations — (7.4 ) 4.9 — Gain on disposal of discontinued operations — 95.3 — — (Loss) income from discontinued operations, before income taxes — 87.9 4.9 — Income tax (benefit) expense — (2.5 ) 10.8 — (Loss) income from discontinued operations net of tax $ — $ 90.4 $ (5.9 ) $ — The fiscal 2016 income tax benefit of $2.5 million impacted by a $0.4 million benefit related to adjust the fiscal 2015 accrual for taxes paid in connection with the $95.3 million gain on the disposition and a $2.1 million benefit related to the $7.4 million loss from discontinued operations. The fiscal 2015 income tax expense of $10.8 million was impacted by approximately $10.0 million of tax expense related to taxes paid, or anticipated to be paid, in connection with the disposition. Fiscal 2016 reflects $0.9 million of Non-U.K. current income tax expense, $3.4 million of Non-U.K. deferred income tax benefit, and none being allocable to the U.K. income tax provision. Fiscal 2015 reflects $14.9 million of Non-U.K. current income tax expense, $4.4 million of non-U.K. deferred income tax benefit, and none being allocable to the U.K. income tax provision. The following table summarizes significant cash and non-cash transactions of the CMDS business that are included within the consolidated statements of cash flows for the fiscal years 2017, 2016 and 2015 and the three months ended December 30, 2016: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Depreciation $ — $ — $ 15.5 $ — Amortization — — 2.3 — Capital expenditures — 1.6 9.5 — All other notes to the consolidated financial statements that were impacted by this discontinued operation have been reclassified accordingly. Mallinckrodt Baker: During fiscal 2010, the Specialty Chemicals business (formerly known as "Mallinckrodt Baker") was sold because its products and customer bases were not aligned with the Company's long-term strategic objectives. This business met the discontinued operations criteria and, accordingly, was included in discontinued operations for all periods presented. During fiscal 2017, 2016 and 2015, the Company recorded a loss , net of tax, of $0.6 million , a gain, net of tax, of $3.0 million and a loss, net of tax of $0.1 million , respectively. The Company recorded a gain of $0.6 million , net of tax, during the three months ended December 30, 2016. The gains and losses were primarily related to the indemnification obligations to the purchaser, which are discussed in Note 18. Other: Prior to the Company's legal separation from Covidien plc ("Covidien") on June 28, 2013, the Company provided and accrued for an indemnification, to the purchaser of a certain legal entity, to indemnify it for tax obligations should the tax basis of certain assets not be recognized. The Company believes that, under the terms of the agreement between the parties, this indemnification obligation has expired. As such, the Company eliminated this liability and recorded a $22.5 million benefit, during fiscal 2015, in discontinued operations within the consolidated statement of income. Divestitures On March 17, 2017, the Company completed its sale of its Intrathecal Therapy business to Piramal Enterprises Limited's subsidiary in the U.K., Piramal Critical Care ("Piramal"), for approximately $203.0 million , including fixed consideration of $171.0 million and contingent consideration of up to $32.0 million . The $171.0 million of fixed consideration consisted of $17.0 million received at closing and a $154.0 million note receivable that is due one year from the transaction closing date. The Company recorded a pre-tax gain on the sale of the business of $56.6 million during fiscal 2017, which excluded any potential proceeds from the contingent consideration and reflects a post-sale working capital adjustment. The financial results of the Intrathecal Therapy business are presented within continuing operations as this divestiture did not meet the criteria for discontinued operations classification. As part of the divestiture and calculation of the gain, the Company wrote off intangible assets of $48.7 million and goodwill of $49.8 million , from the Specialty Brands segment, ascribed to the Intrathecal Therapy business. The Company is committed to reimburse up to $7.3 million of product development expenses incurred by Piramal, of which $6.5 million remains on the consolidated balance sheet as of December 29, 2017. The remaining items included in the gain calculation are attributable to inventory transferred and transaction costs incurred by the Company. License of Intellectual Property The Company was involved in patent disputes with a counterparty relating to certain intellectual property related to extended-release oxymorphone. In December 2013, the counterparty agreed to pay the Company an upfront cash payment of $4.0 million and contractually obligated future payments of $8.0 million through July 2018, in exchange for the withdrawal of all claims associated with the intellectual property and a license to utilize the Company's intellectual property. The Company has completed the earnings process associated with the agreement and recorded an $11.7 million gain, included within gains on divestiture and license, during fiscal 2014.

Acquisitions and License Agreem

Acquisitions and License Agreements	12 Months Ended
	Dec. 29, 2017
Business Combinations [Abstract]
Acquisitions and License Agreements	6. Acquisitions and License Agreements Business Acquisitions Ocera Therapeutics, Inc. On December 11, 2017, the Company acquired Ocera Therapeutics, Inc. ("Ocera") for upfront consideration of approximately $42.4 million , of which $1.9 million of the consideration was paid subsequent to December 29, 2017, and contingent consideration up to $75.0 million based on the successful completion of certain development and sales milestones ("the Ocera Acquisition"). Ocera is a clinical stage biopharmaceutical company focused on the development and commercialization of novel therapeutics for orphan and other serious liver diseases with a high unmet medical need. Ocera’s developmental product MNK-6105 (previously OCR-002), an ammonia scavenger, is being studied for treatment of hepatic encephalopathy, a neuropsychiatric syndrome associated with hyperammonemia, a complication of acute or chronic liver disease. The Ocera Acquisition was funded with cash on hand. InfaCare Pharmaceutical Corporation On September 25, 2017, the Company acquired InfaCare Pharmaceutical Corporation ("InfaCare") in a transaction valued at approximately $80.4 million , with additional payments of up to $345.0 million dependent on regulatory and sales milestones ("the InfaCare Acquisition"). Consideration for the transaction consisted of approximately $37.2 million in cash paid to the prior shareholders of InfaCare and the assumption of approximately $43.2 million of debt and other liabilities, which was repaid in conjunction with the InfaCare Acquisition. InfaCare is focused on development and commercialization of proprietary pharmaceuticals for neonatal and pediatric patient populations. InfaCare's developmental product stannsoporfin, a heme oxygenase inhibitor, is under investigation for its potential to reduce the production of bilirubin, the elevation of which can contribute to serious consequences in infants. The InfaCare Acquisition was funded with cash on hand. Stratatech Corporation On August 31, 2016, the Company acquired a developmental program from Stratatech Corporation - which includes StrataGraft®, a regenerative skin tissue and a technology platform for genetically enhanced skin tissues - for upfront consideration of $76.0 million , and contingent milestone payments, which are primarily regulatory, and royalty obligations that could result in up to $121.0 million of additional consideration ("the Stratatech Acquisition"). Stratatech is a regenerative medicine company focused on the development of unique, proprietary skin substitute products. Developmental products include StrataGraft® regenerative skin tissue ("StrataGraft") and a technology platform for genetically enhanced skin tissues. The Stratatech Acquisition was funded through cash on hand. Hemostasis Products On February 1, 2016, the Company acquired three commercial stage topical hemostasis drugs from The Medicines Company ("the Hemostasis Acquisition") - RECOTHROM® Thrombin topical (Recombinant) ("Recothrom"), PreveLeak TM Surgical Sealant ("PreveLeak"), and RAPLIXA TM (Fibrin Sealant (Human)) ("Raplixa") - for upfront consideration of $173.5 million , inclusive of existing inventory, and contingent sales-based milestone payments that could result in up to $395.0 million of additional consideration. The Hemostasis Acquisition was funded through cash on hand. As the Company shifts its focus to the critical care, autoimmune and rare disease spaces, it has entered into a transaction to sell the Recothrom and PreveLeak assets and is currently evaluating strategic options for Raplixa. See further discussion in Notes 12, 20 and 24 to the consolidated financial statements. Therakos, Inc. On September 25, 2015, the Company acquired Therakos, Inc. ("Therakos") through the acquisition of all the outstanding common stock of TGG Medical Solutions, Inc., the parent holding company of Therakos, in a transaction valued at approximately $1.3 billion , net of cash acquired ("the Therakos Acquisition"). Consideration for the transaction consisted of approximately $1.0 billion in cash paid to TGG Medical Solutions, Inc. shareholders and the assumption of approximately $0.3 billion of Therakos third-party debt, which was repaid in conjunction with the Therakos Acquisition. The acquisition and repayment of debt was funded through the issuance of $750.0 million aggregate principal amount of senior unsecured notes, a $500.0 million borrowing under a revolving credit facility and cash on hand. Therakos' primary immunotherapy products relate to the administering of extracorporeal photopheresis therapies through its UVAR XTS® and Cellex TM Photopheresis Systems. Ikaria, Inc. On April 16, 2015, the Company acquired Ikaria, Inc. ("Ikaria") through the acquisition of all the outstanding common stock of Compound Holdings II, Inc., the parent holding company of Ikaria, in a transaction valued at approximately $2.3 billion , net of cash acquired ("the Ikaria Acquisition"). Consideration for the transaction consisted of approximately $1.2 billion in cash paid to Compound Holdings II, Inc. shareholders and the assumption of approximately $1.1 billion of Ikaria third-party debt, which was repaid in conjunction with the Ikaria Acquisition. The acquisition and repayment of debt was funded through the issuance of $1.4 billion aggregate principal amount of senior unsecured notes, a $240.0 million borrowing under the Revolver, which was repaid subsequent to the transaction, and cash on hand. Ikaria's primary product is INOMAX® (nitric oxide) for inhalation ("Inomax"), a vital treatment option in neonatal critical care. Fair Value Allocation The following amounts represent the allocation of the fair value of the identifiable assets acquired and liabilities assumed for the respective acquisitions: Ocera (2) InfaCare (2) Stratatech Hemostasis (1) Therakos Ikaria Acquisition Date December 2017 September 2017 August 2016 February 2016 September 2015 April 2015 Cash $ 1.0 $ 1.3 $ 0.2 $ 3.3 $ 41.3 $ 77.3 Accounts receivable — — 1.3 — 22.0 73.8 Inventory — — — 94.6 23.5 26.3 Intangible assets 64.5 113.5 99.8 132.7 1,170.0 1,971.0 Goodwill (non-tax deductible) 25.1 11.4 55.1 3.3 429.9 795.0 Other assets, current and non-current 0.4 0.1 1.9 7.9 18.2 100.5 Total assets acquired 91.0 126.3 158.3 241.8 1,704.9 3,043.9 Current liabilities 14.5 14.5 4.3 3.6 24.7 33.0 Other liabilities (non-current) — — — 10.6 0.6 15.8 Deferred tax liabilities, net (non-current) 23.2 8.7 22.1 2.1 315.7 620.5 Contingent consideration (non-current) 12.8 35.0 54.9 52.0 — — Total debt — 30.0 1.0 — 344.8 1,121.0 Total liabilities assumed 50.5 88.2 82.3 68.3 685.8 1,790.3 Net assets acquired $ 40.5 $ 38.1 $ 76.0 $ 173.5 $ 1,019.1 $ 1,253.6 (1) During fiscal 2017, the Company recorded a non-restructuring impairment charge relating to one of its intangible assets and reduced the associated contingent consideration. Refer to Note 12 and 20, respectively, for further information. (2) The fair value allocations for these acquisitions are preliminary and subject to measurement period adjustments. The following reconciles the total consideration to net assets acquired: Ocera InfaCare Stratatech Hemostasis Therakos Ikaria Total consideration, net of cash $ 63.4 $ 71.8 $ 130.7 $ 222.2 $ 977.8 $ 1,176.3 Plus: cash assumed in acquisition 1.0 1.3 0.2 3.3 41.3 77.3 Total consideration 64.4 73.1 130.9 225.5 1,019.1 1,253.6 Less: unpaid purchase consideration (1.9 ) — — — — — Less: non-cash contingent consideration (22.0 ) (35.0 ) (54.9 ) (52.0 ) — — Net assets acquired $ 40.5 $ 38.1 $ 76.0 $ 173.5 $ 1,019.1 $ 1,253.6 Intangible assets acquired consist of the following: Acquisition Intangible Asset Acquired Amount Amortization Period Discount Rate Ocera In-process research and development - MNK-6105 $ 64.5 Non-Amortizable 15.5 % InfaCare In-process research and development - stannsoporfin 113.5 Non-Amortizable 13.5 % Stratatech In-process research and development - StrataGraft 99.8 Non-Amortizable 16.5 % Hemostasis Completed technology - Raplixa (1) 73.0 15 years 17.0 % Hemostasis Completed technology - Recothrom 42.7 13 years 16.0 % Hemostasis Completed technology - PreveLeak 17.0 13 years 17.0 % Therakos Completed technology - Extracorporeal photopheresis treatment therapies 1,170.0 15 years 17.0 % Ikaria Completed technology 1,820.0 15 years 14.5 % Ikaria Trademark 70.0 22 years 14.5 % Ikaria In-process research and development - Terlipressin 81.0 Non-Amortizable 17.0 % (1) During fiscal 2017, the Company recorded a non-restructuring impairment charge relating to the Raplixa intangible asset. Refer to Note 12 for further information. The fair value of the intangible assets were determined using the income approach. The fair value of the IPR&D, completed technology and trademark was determined using the income approach, which is a valuation technique that provides an estimate of fair value of the assets based on the market participant expectations of cash flows the asset would generate. The discount rates were developed after assigning a probability of success to achieving the projected cash flows based on the current stage of development, inherent uncertainty in the FDA approval process and risks associated with commercialization of a new product. Based on the Company's preliminary estimate, the excess of purchase price over net tangible and intangible assets acquired resulted in goodwill, which represents future product development, the assembled workforce, and the tax status of the transaction. The goodwill is not deductible for U.S. income tax purposes. All assets acquired are included within the Company's Specialty Brands segment. Financial Results - The amount of net sales and earnings included in the Company's results for the periods presented were as follows: Fiscal Year Ended Three Months Ended Net sales December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Ocera $ — $ — $ — $ — InfaCare — — — — Therakos 214.9 207.6 — 47.4 Ikaria 515.1 491.5 191.9 121.4 Total $ 730.0 $ 699.1 $ 191.9 $ 168.8 Operating income Ocera $ (0.4 ) $ — $ — $ — InfaCare (5.4 ) — — — Therakos 27.0 12.5 — 9.2 Ikaria 202.8 201.1 47.1 51.0 Total $ 224.0 $ 213.6 $ 47.1 $ 60.2 The amount of amortization on acquired intangible assets included within operating income (loss) for the periods presented was as follows: Fiscal Year Ended Three Months Ended Intangible asset amortization December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Ocera $ — $ — $ — $ — InfaCare — — — — Therakos 61.7 78.0 — 19.5 Ikaria 124.5 124.5 57.1 31.1 Total $ 186.2 $ 202.5 $ 57.1 $ 50.6 During fiscal 2017, 2016 and 2015 and the three months ended December 30, 2016, the Company recognized $10.1 million , $24.3 million , $44.1 million and $3.6 million , respectively, of expense associated with fair value adjustments of acquired inventory. This expense was included within cost of sales. Acquisition-Related Costs - Acquisition-related costs incurred for each of the acquisitions discussed above were as follows: Fiscal Year Ended Three Months Ended Acquisition-related costs December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Ocera $ 0.9 $ — $ — $ — Xenon Licensing Agreement 0.1 — — — InfaCare 1.2 — — — Stratatech — 3.7 — — Hemostasis Products — 2.7 — 0.1 Therakos — 0.3 22.5 — Ikaria — 0.2 30.9 — Total acquisition-related costs $ 2.2 $ 6.9 $ 53.4 $ 0.1 License Agreements Xenon Gas for Inhalation On October 2, 2017, the Company entered into a licensing agreement for development and commercialization of NeuroproteXeon Inc.'s ("NeuroproteXeon" and "the Xenon Licensing Agreement") investigational, pharmaceutical-grade xenon gas for inhalation therapy being evaluated to improve survival and functional outcomes for patients resuscitated after a cardiac arrest. If approved, xenon gas for inhalation will expand the Company's portfolio of hospital drug-device combination products providing therapies for critically ill patients. The Company paid $10.0 million upfront with cash on hand to reimburse NeuroproteXeon for certain product development costs, and gained exclusive rights to commercialize the therapy, if approved, in the U.S., Canada, Japan and Australia. The Licensing Agreement includes additional payments of up to $25.0 million dependent on developmental, regulatory and sales milestones. In addition, NeuroproteXeon will receive tiered royalties on applicable worldwide net sales and a transfer price for commercial product supply. NeuroproteXeon will continue to be responsible for the cost of development and will manage the development of the product in collaboration with the Company. The initial $10.0 million upfront cash payment was recorded within R&D expense during the year ended December 29, 2017. Of the $25.0 million additional payments, certain payments may be expensed as R&D, cost of sales, or capitalized as an intangible asset dependent upon the successful completion of certain milestone events. Mesoblast In January 2017, $21.5 million of consideration was remitted to Mesoblast Limited ("Mesoblast") in exchange for equity shares and rights to a nine month exclusivity period related to any potential commercial and development agreements the Company may enter into for Mesoblast's therapy products used to treat acute graft versus host disease and/or chronic lower back pain. As a result of this transaction the Company recorded an available for sale investment of $19.7 million included within prepaid and other current assets and an intangible asset of $1.8 million in the consolidated balance sheet. This intangible asset was fully amortized as of December 29, 2017 as the nine month exclusivity period had ended. Ofirmev As part of the acquisition of Cadence Pharmaceuticals, Inc. ("Cadence" or "Cadence Acquisition") in March 2014, the Company acquired the exclusive development and commercialization rights to Ofirmev in the U.S. and Canada, as well as the rights to the patents and technology, which were originally in-licensed by Cadence from BMS in March 2006. BMS sublicensed these rights to Cadence under a license agreement with SCR Pharmatop S.A. ("Pharmatop"), and the Company has the right to grant sublicenses to third parties. Under this license agreement, the Company may be obligated to make future milestone payments of up to $25.0 million upon the achievement of certain levels of net sales, of which $10.0 million was paid during fiscal 2015. In addition, the Company is obligated to pay royalties on sales of the product. During fiscal 2017 , 2016 , 2015 and the three months ended December 30, 2016, the Company paid royalties of $53.9 million , $46.3 million , $43.9 million and $14.7 million , respectively, which were recorded within cost of sales on the consolidated statements of income. Exalgo In 2009, the Company's Specialty Brands segment acquired the rights to market and distribute the pain management drug EXALGO® (hydromorphone HCl) extended-release tablets (CII) ("Exalgo") in the U.S. Under the license agreement, the Company is obligated to make additional payments of up to $73.0 million based on the successful completion of specified development and regulatory milestones. Through fiscal 2017 , $65.0 million of additional payments had been made, with $55.0 million being capitalized as an intangible asset. The Company is also required to pay royalties on sales of the product. During fiscal 2017 , 2016 , 2015 and the three months ended December 30, 2016, the Company paid royalties of $0.2 million , $0.9 million , $3.2 million and $0.2 million , respectively, which were recorded within cost of sales on the consolidated statements of income. Depomed In 2009, the Company's Specialty Brands segment licensed worldwide rights to utilize Depomed, Inc.'s ("Depomed") Acuform gastric retentive drug delivery technology for the exclusive development of four products. Under this license agreement, the Company may be obligated to pay up to $64.0 million in development milestone payments. Through fiscal 2017 , approximately $22.0 million of these payments have been made by the Company. During fiscal 2014, upon approval by the FDA for XARTEMIS™ XR (oxycodone HCl and acetaminophen) extended release tablets CII ("Xartemis XR"), the Company made a milestone payment of $10.0 million , which was capitalized as an intangible asset. During the three months ended December 30, 2016, the Company elected to discontinue this product and recorded a $7.3 million non-restructuring impairment charge associated with the Xartemis intangible asset.

Restructuring and Related Charg

Restructuring and Related Charges	12 Months Ended
	Dec. 29, 2017
Restructuring and Related Activities [Abstract]
Restructuring and Related Charges	7. Restructuring and Related Charges During fiscal 2013, the Company launched a restructuring program designed to improve its cost structure ("the 2013 Mallinckrodt Program"). The 2013 Mallinckrodt Program included actions across the Specialty Brands, Specialty Generics and former Global Medical Imaging segments, as well as within corporate functions. The Company expected to incur charges of $100.0 million to $125.0 million under this program as the specific actions required to execute on these initiatives were identified and approved. The 2013 Mallinckrodt Program is substantially complete. In July 2016, the Company's Board of Directors approved a $100.0 million to $125.0 million restructuring program ("the 2016 Mallinckrodt Program") designed to further improve its cost structure, as the Company continues to transform its business. The 2016 Mallinckrodt Program is expected to include actions across the Specialty Brands and Specialty Generics segments, as well as within corporate functions. There is no specified time period associated with the 2016 Mallinckrodt Program. In addition to the 2016 Mallinckrodt Program and the 2013 Mallinckrodt Program, the Company has taken restructuring actions to generate synergies from its acquisitions. Net restructuring and related charges by segment from continuing operations are as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Specialty Brands $ 25.4 $ 23.3 $ 36.5 $ 2.6 Specialty Generics 7.7 3.4 4.5 0.8 Corporate 3.3 11.5 4.3 1.9 Restructuring and related charges, net 36.4 38.2 45.3 5.3 Less: accelerated depreciation (5.2 ) (4.9 ) (0.3 ) (1.5 ) Restructuring charges, net $ 31.2 $ 33.3 $ 45.0 $ 3.8 Net restructuring and related charges by program from continuing operations are comprised of the following: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 2016 Mallinckrodt Program $ 36.2 $ 8.3 $ — $ 5.2 2013 Mallinckrodt Program (0.7 ) 26.2 12.0 — Acquisition programs 0.9 3.7 33.6 0.1 Other programs — — (0.3 ) — Total programs 36.4 38.2 45.3 5.3 Less: non-cash charges, including impairments and accelerated share based compensation expense (5.2 ) (4.9 ) (10.1 ) (1.5 ) Total charges expected to be settled in cash $ 31.2 $ 33.3 $ 35.2 $ 3.8 Non-cash charges in fiscal 2015 include $9.8 million of accelerated share based compensation expense related to employee terminations, primarily related to the acquisition of Questcor Pharmaceuticals, Inc. ("Questcor") in fiscal 2014. The following table summarizes cash activity for restructuring reserves, substantially all of which related to employee severance and benefits and exiting of certain facilities: 2016 Mallinckrodt Program 2013 Mallinckrodt Program Acquisition Programs Other Programs Total Balance at September 26, 2014 $ — $ 26.6 $ 7.9 $ 0.4 $ 34.9 Charges from continuing operations — 11.7 25.3 — 37.0 Charges from discontinued operations — 4.7 — — 4.7 Changes in estimate from continuing operations — — (1.5 ) (0.3 ) (1.8 ) Changes in estimate from discontinued operations — (8.9 ) — — (8.9 ) Cash payments — (22.5 ) (21.7 ) (0.1 ) (44.3 ) Reclassifications (1) — (3.0 ) — — (3.0 ) Currency translation — (0.6 ) — — (0.6 ) Balance at September 25, 2015 — 8.0 10.0 — 18.0 Charges from continuing operations 6.4 24.6 5.0 — 36.0 Charges from discontinued operations — 2.5 — — 2.5 Changes in estimate from continuing operations — (1.4 ) (1.3 ) — (2.7 ) Changes in estimate from discontinued operations — (0.3 ) — — (0.3 ) Cash payments (0.2 ) (20.3 ) (13.2 ) — (33.7 ) Reclassifications (1) — (1.3 ) — — (1.3 ) Balance at September 30, 2016 6.2 11.8 0.5 — 18.5 Charges from continuing operations 3.7 — 0.1 — 3.8 Cash payments (0.4 ) (6.7 ) (0.4 ) — (7.5 ) Balance at December 30, 2016 9.5 5.1 0.2 — 14.8 Charges from continuing operations 35.8 — 0.9 — 36.7 Changes in estimate from continuing operations (4.8 ) (0.7 ) — — (5.5 ) Cash payments (26.1 ) (4.4 ) (0.3 ) — (30.8 ) Reclassifications (1) 0.3 — — — 0.3 Balance at December 29, 2017 $ 14.7 $ — $ 0.8 $ — $ 15.5 (1) Represents the reclassification of pension and other postretirement benefits from restructuring reserves to pension and postretirement obligations. Net restructuring and related charges, including associated asset impairments, incurred cumulative to date related to the 2016 and 2013 Mallinckrodt Programs are as follows: 2016 Mallinckrodt Program 2013 Mallinckrodt Program Specialty Brands $ 32.5 $ 18.8 Specialty Generics 9.1 18.3 Discontinued Operations (including Nuclear and CMDS) — 69.9 Corporate 9.0 17.7 $ 50.6 $ 124.7 Substantially all of the restructuring reserves are included in accrued and other current liabilities on the Company's consolidated balance sheets.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 29, 2017
Income Tax Disclosure [Abstract]
Income Taxes	8. Income Taxes On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the “TCJA” or "U.S. Tax Reform"). The TCJA makes broad and complex changes to the U.S. tax code, the effects of which have been incorporated into the Company’s fiscal 2017 provision for income taxes, as applicable. The TCJA provisions effective within 2017, include, but are not limited to (1) requiring a one-time transition tax on certain undistributed earnings of the Company’s foreign subsidiaries of U.S. entities, (2) bonus depreciation that will allow for full expensing of qualified property, and (3) reducing the U.S. federal corporate statutory tax rate from 35% to 21% . The TCJA also establishes new tax laws that will affect fiscal 2018, including, but not limited to (1) elimination of the corporate alternative minimum tax, (2) creation of the base erosion anti-abuse tax, a new minimum tax, (3) a general elimination of U.S. federal income taxes on dividends from non-U.S. subsidiaries, (4) a new provision designed to tax global intangible low-taxed income, which allows for the possibility of using foreign tax credits and a deduction of up to 50% to offset the income tax liability, (5) tightening the limitation on deductible interest expense, (6) limitations on net operating losses generated after December 31, 2017 to 80% of taxable income, and (7) reductions to the amount of the orphan drug research credit generated after December 31, 2017. Accounting Standards Codification ("ASC") Topic 740, Income Taxes ("ASC 740"), requires companies to recognize the effects of tax law changes in the period of enactment, which for Mallinckrodt is the fourth quarter of 2017, even though the effective date of most provisions of TCJA is January 1, 2018. The SEC staff issued Staff Accounting Bulletin ("SAB") 118, which provides guidance on accounting for the tax effects of the TCJA. SAB 118 provides a measurement period that should not extend beyond one year from the TCJA enactment date for companies to complete the accounting. In accordance with SAB 118, a company must reflect the income tax effects of those aspects of the TCJA for which the accounting is complete. To the extent that a company’s accounting for certain income tax effects of the TCJA is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate in the financial statements. If a company cannot determine a provisional estimate to be included in the financial statements, it should continue to apply ASC 740 on the basis of the provisions of the tax laws that were in effect immediately before the enactment of the TCJA. In connection with the Company's initial analysis of the impact of the TCJA, a discrete net tax benefit of $456.9 million was recognized in fiscal 2017, primarily for the adjustment of the Company’s U.S. net deferred income tax liabilities for the reduction of the U.S. federal corporate statutory tax rate to 21%. For various reasons that are discussed more fully below, the Company has not yet completed its accounting for the income tax effects of certain elements of the TCJA and therefore a reasonable estimate of such impact has been provided. The TCJA reduces the U.S. federal corporate tax rate to 21%, effective January 1, 2018. For the Company's U.S. net deferred income tax liabilities a provisional decrease of $444.8 million was recognized resulting in a corresponding deferred income tax benefit in fiscal 2017. While the Company is able to make a reasonable estimate of the impact of the reduction in the U.S. federal corporate statutory tax rate, it may be affected by other analyses related to the TCJA, including, but not limited to, having a U.S. tax return year that straddles the effective date of the statutory rate change and that is different than the Company's financial statement year, the calculation of deemed repatriation of deferred foreign income, and the state tax effect of adjustments made to federal temporary differences. The one-time transition tax under the TCJA on certain of the Company’s subsidiaries is a tax on previously untaxed cumulative undistributed earnings. To determine the amount of such tax, the Company must determine, in addition to other factors, the amount of post-1986 cumulative undistributed earnings of the relevant subsidiaries, the amount of non-U.S. income taxes paid on such earnings, and the application of the law and interpretative guidance to the Company's global legal entity structure. While the Company currently estimates this item will not result in any current or future tax, additional information will continue to be gathered to finalize this conclusion. Because of the complexity and uncertainties of the new global intangible low-taxed income rules, the Company continues to evaluate this portion of the TCJA and the application of ASC 740. Under GAAP, the Company is allowed to make an accounting policy choice of either (1) treating taxes due on future U.S. inclusions in taxable income related to global intangible low-taxed income as a current-period expense when incurred or (2) factoring such amounts into a company’s measurement of its deferred taxes. The Company's selection of an accounting policy with respect to these new tax rules will depend on whether it expects to have future U.S. inclusions in taxable income related to global intangible low-taxed income and, if so, what the tax impact is expected to be. Whether the Company expects to have future U.S. inclusions in taxable income depends on not only the Company's current structure and estimated future results of global operations but also its intent and ability to modify its structure and/or business. While the Company estimates these rules will not have a material tax impact, it is not yet able to finalize the effect of this portion of the TCJA. Therefore, the Company has not made any adjustments related to this item in its consolidated financial statements and has not made a policy decision regarding whether to record deferred taxes on global intangible low-taxed income. Finally, the Company must assess whether its valuation allowance analyses are affected by the various aspects of the TCJA. Since, as discussed herein, the Company has recorded provisional amounts related to certain portions of the TCJA, any corresponding determination of the need for or change in a valuation allowance is also provisional. The U.K. and non-U.K. components of income (loss) from continuing operations before income taxes were as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 U.K. $ (165.9 ) $ (275.3 ) $ (107.5 ) $ (97.4 ) Non-U.K. 227.5 508.7 214.8 (201.1 ) Total $ 61.6 $ 233.4 $ 107.3 $ (298.5 ) Significant components of income taxes related to continuing operations are as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Current: U.K. $ 0.4 $ 0.3 $ 0.2 $ — Non-U.K. 37.7 120.5 67.3 82.0 Current income tax provision 38.1 120.8 67.5 82.0 Deferred: U.K. $ 0.6 $ 0.7 $ (0.8 ) $ (0.5 ) Non-U.K. (1,748.3 ) (377.1 ) (196.0 ) (203.2 ) Deferred income tax benefit (1,747.7 ) (376.4 ) (196.8 ) (203.7 ) $ (1,709.6 ) $ (255.6 ) $ (129.3 ) $ (121.7 ) The fiscal 2017 U.K. current income tax provision reflects a tax benefit of $14.3 million from utilization of net operating losses. The U.K. net operating loss utilization relates to net operating losses carried forward from the three months ended December 30, 2016. The fiscal 2017 non-U.K. current income tax provision reflects a tax benefit of $57.2 million from utilization of net operating losses and $5.6 million of U.S. credits. In addition, the non-U.K. current income tax provision includes a tax benefit of $27.2 million related to carryback claims filed in fiscal 2017. The non-U.K. net operating loss utilization relates to net operating losses carried forward from the three months ended December 30, 2016. The U.S. credit utilization is comprised of credits carried forward from the three months ended December 30, 2016 and generated during fiscal 2017 The fiscal 2016 U.K. current income tax provision reflects a tax benefit of $1.0 million from utilization of net operating losses. The U.K. net operating loss utilization is comprised of net operating losses carried forward from fiscal 2015. The fiscal 2016 non-U.K. current income tax provision reflects a tax benefit of $29.2 million from utilization of net operating losses and $9.5 million of U.S. credits. The non-U.K. net operating loss utilization is comprised of $17.9 million of net operating losses acquired in conjunction with the Hemostasis Acquisition and the remainder of the utilization relates to net operating losses carried forward from fiscal 2015. The U.S. credit utilization is comprised of credits carried forward from fiscal 2015 and generated during fiscal 2016. The fiscal 2015 non-U.K. current income tax provision reflects a tax benefit of $7.0 million from utilization of net operating losses (primarily in the U.S.) and $14.3 million of U.S. credits. The net operating loss utilization is comprised of $4.8 million of net operating losses acquired in conjunction with the Ikaria Acquisition and the remainder of the utilization relates to net operating losses carried forward from fiscal 2014. The U.S. credit utilization is comprised of $7.2 million of credits acquired in conjunction with the Ikaria Acquisition and the remainder of the utilization relating to credits carried forward or generated during fiscal 2015. The three months ended December 30, 2016 non-U.K. current income tax provision reflects a tax benefit of $0.3 million from utilization of net operating losses and $2.0 million of U.S. credits. The non-U.K. net operating loss utilization relates to net operating losses carried forward from fiscal 2016. The U.S. credit utilization is comprised of credits carried forward from fiscal 2016 and generated during the three months ended December 30, 2016. During fiscal years 2017, 2016, and 2015 net cash payments for income taxes was $73.4 million , $165.4 million and $123.8 million , respectively. During the three months ended December 30, 2016 net cash payments for income taxes was $95.6 million . The Company has a provincial tax holiday in Canada that expires on April 1, 2027. The tax holiday reduced non-U.K. tax expense by $1.8 million , $1.0 million and $5.1 million for the fiscal years 2017, 2016 and 2015, respectively. Due to an operating loss, there is no benefit from the tax holiday for the three months ended December 30, 2016. The reconciliation between U.K. income taxes at the statutory rate and the Company's provision for income taxes on continuing operations is as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Provision (benefit) for income taxes at U.K. statutory income tax rate (1) $ 11.7 $ 46.6 $ 21.4 $ (59.7 ) Adjustments to reconcile to income tax provision: Rate difference between U.K. and non-U.K. jurisdictions (2) (5) (219.9 ) (249.3 ) (152.9 ) (123.0 ) Valuation allowances, nonrecurring (3.7 ) 2.1 (2.1 ) — Adjustments to accrued income tax liabilities and uncertain tax positions (7) 5.1 (14.9 ) (7.0 ) 0.9 Interest and penalties on accrued income tax liabilities and uncertain tax positions 0.2 (16.4 ) 0.3 (0.1 ) Investment in partnership — — — (12.7 ) Credits, principally research and orphan drug (3) (4) (13.8 ) (33.7 ) (8.1 ) (0.7 ) Impairments non deductible — — — 75.3 Permanently nondeductible and nontaxable items 6.4 7.9 14.7 1.6 Pension plan settlement, release of tax effects lodged in other comprehensive income (2.4 ) — — — Divestiture of Intrathecal Therapy Business 18.2 — — — U.S. Tax Reform (6) (456.9 ) — — — Legal Entity Reorganization (7) (1,054.8 ) — — — Other 0.3 2.1 4.4 (3.3 ) Benefit for income taxes $ (1,709.6 ) $ (255.6 ) $ (129.3 ) $ (121.7 ) (1) The statutory tax rate reflects the U.K. statutory tax rate of 19% for fiscal 2017 and 20% for fiscal 2016, 2015 and the three months ended December 30, 2016. (2) Includes the impact of certain recurring valuation allowances for U.K. and non-U.K. jurisdictions. (3) During fiscal 2015, the Research Credit tax law was extended, with a retroactive effective date of January 1, 2014. As such, fiscal 2015 includes approximately $3.6 million of credit related to the period January 1, 2014 through September 26, 2014. (4) During fiscal 2016, the Company realized a tax benefit of $27.4 million resulting from a U.K. tax credit on a dividend between affiliates. (5) During the three months ended December 30, 2016, the rate difference between U.K. and non-U.K. jurisdictions was favorably impacted by a benefit of $16.1 million on a $102.0 million settlement with the Federal Trade Commission and a benefit of $34.5 million on a $207.0 million goodwill impairment in the Specialty Generics segment. (6) Reflects redetermination of the Company's deferred tax liabilities as a result of the new U.S. statutory income tax rate of 21% at the date of enactment. Other line items, to the extent U.S. related, are reflected at the former U.S. statutory income tax rate of 35%. (7) Associated unrecognized tax benefit netted within this line. The rate difference between U.K. and Non-U.K. jurisdictions changed from $249.3 million of tax benefit to $219.9 million of tax benefit for fiscal 2016 to fiscal 2017, respectively. The $29.4 million decrease in the tax benefit included $37.6 million of decreases primarily attributed to the divestiture of the Intrathecal Therapy business and the planned divestiture of the PreveLeak and Recothrom assets and fiscal 2016 one-time items that did not recur in fiscal 2017, and $15.2 million of decreases to the tax benefit associated with the impact of U.S. Tax Reform on a U.S. tax return year that straddles the effective date of the statutory rate change; partially offset by increases of $23.4 million to the tax benefit attributed to changes in operating income and termination and settlement of the Company's funded U.S. pension plan in fiscal 2017. The rate difference between U.K. and Non-U.K. jurisdictions changed from $152.9 million of tax benefit to $249.3 million of tax benefit for fiscal 2015 to fiscal 2016, respectively. This change was predominately related to recent acquisitions, which resulted in more income in lower tax rate jurisdictions and less income in the higher tax rate U.S. jurisdiction relative to income in all jurisdictions. The change in the lower tax rate jurisdictions was predominately due to recent acquisitions, which resulted in more income in lower tax rate jurisdictions and less income in the higher tax rate U.S. jurisdiction relative to income in all jurisdictions. The change in the lower tax rate jurisdictions was primarily attributable to increased operating income partially offset by amortization. The change in the U.S. jurisdiction was primarily attributable to increased amortization and the cost of financing recent acquisitions. The $96.4 million increase in the tax benefit included increases of $146.3 million of tax benefit attributed to changes in operating income and $32.0 million of tax benefit related to acquisition and other non-acquisition related items; partially offset by $56.8 million of increased tax expense to the change in amortization and a $25.1 million decrease to the U.S. state tax benefit associated with the impact of recent acquisitions, integration thereof, and legislative changes. During the three months ended December 29, 2017, the Company completed a reorganization of its legal entity ownership (“the Reorganization”) to align with its ongoing transformation to become an innovation-driven specialty pharmaceuticals growth company. Many factors were considered in effecting the Reorganization, including streamlining treasury functions, simplifying legal entity reporting processes, and capital allocation efficiencies. Given this Reorganization, the Internal Revenue Code required the Company to reallocate its tax basis from an investment in shares of a wholly-owned subsidiary to assets within another legal entity with no corresponding change in accounting basis. A deferred tax liability was not recognized on the wholly-owned subsidiary as there is a means for its recovery in a tax-free manner. The reallocation of tax basis resulted in a decrease to the net deferred tax liabilities associated with the assets within the other legal entity. As a result, during fiscal 2017, the Company recognized an income tax benefit, net of unrecognized tax benefits, of $1,054.8 million primarily as a result of a reduction to its net deferred tax liabilities. In fiscal 2017, the Company recognized an income tax expense of $5.2 million associated with the Nuclear Imaging business divestiture, as discussed in Note 5, in discontinued operations within the consolidated statement of income. The following table summarizes the activity related to the Company's unrecognized tax benefits, excluding interest: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Balance at beginning of period $ 118.7 $ 89.2 $ 82.0 $ 114.8 Additions related to current year tax positions 79.9 63.8 4.5 5.0 Additions related to prior period tax positions 0.3 10.8 19.9 — Reductions related to prior period tax positions (13.6 ) (37.8 ) (7.7 ) (1.1 ) Reductions related to disposition transactions — (6.6 ) — — Settlements — (2.6 ) (7.8 ) — Lapse of statute of limitations (2.8 ) (2.0 ) (1.7 ) — Balance at end of period $ 182.5 $ 114.8 $ 89.2 $ 118.7 During fiscal 2015, the Company made a payment of $8.9 million ( $7.4 million of tax and $1.5 million of interest) to the U.S. IRS in connection with the settlement of certain tax matters for 2008 and 2009. Unrecognized tax benefits, excluding interest, are reported in the following consolidated balance sheet captions in the amount shown: December 29, 2017 December 30, 2016 Accrued and other current liabilities $ 1.5 $ — Other income tax liabilities 82.6 58.3 Deferred income taxes (non-current liability) 98.4 60.4 $ 182.5 $ 118.7 Included within total unrecognized tax benefits at December 29, 2017 , September 30, 2016, September 25, 2015 and December 30, 2016, were $180.8 million , $113.1 million , $87.4 million and $116.9 million respectively, of unrecognized tax benefits, which if favorably settled would benefit the effective tax rate. The remaining unrecognized tax benefits for each period would be offset by the write-off of related deferred and other tax assets, if recognized. During fiscal 2017 , the Company recorded $2.6 million of additional interest through tax provision and acquisition accounting and decreased accrued interest by $2.7 million related to prior period reductions. During fiscal 2016 , 2015 and the three months ended December 30, 2016, the Company accrued additional interest of $4.1 million , $5.7 million and zero , respectively. The total amount of accrued interest related to uncertain tax positions was $7.1 million , $7.2 million , $41.7 million and $7.1 million , respectively. It is reasonably possible that within the next twelve months, as a result of the resolution of various U.K. and non-U.K. examinations and appeals and the expiration of various statutes of limitation, that the unrecognized tax benefits could decrease by up to $38.4 million . Interest and penalties could decrease by up to $4.9 million . Income taxes payable, including uncertain tax positions and related interest accruals, is reported in the following consolidated balance sheet captions in the amounts shown: December 29, 2017 December 30, 2016 Income taxes payable $ 15.8 $ 101.7 Other income tax liabilities 94.1 70.4 $ 109.9 $ 172.1 Tax items inherent in other assets decreased from $67.2 million at December 30, 2016 to zero as of December 29, 2017. The $67.2 million decrease was as a result of the early adoption of ASU 2016-16 which moved capitalized tax payments associated with non-current deferred intercompany transactions to retained earnings. Tax items inherent in prepaid expenses and other current assets decreased from $50.3 million at December 30, 2016 to $6.1 million as of December 29, 2017. The $44.2 million decrease was primarily due to the receipt of a $25.4 million U.K. tax credit receivable and a $7.8 million decrease related to the early adoption of ASU 2016-16. Prepaid expenses and other current assets includes $4.2 million and $40.2 million of receivables associated with tax payments on account with the taxing authorities and tax payments of $1.9 million and $10.1 million associated with current deferred intercompany transactions at December 29, 2017 and December 30, 2016, respectively. December 29, 2017 December 30, 2016 Other assets $ — $ 67.2 Prepaid expenses and other current assets 6.1 50.3 $ 6.1 $ 117.5 With a few exceptions, as of December 29, 2017 , the earliest open years for U.S. federal and state tax jurisdictions are 2010 and 2009 , respectively. Additionally, a number of tax periods from 2013 to present are subject to examination by tax authorities in various jurisdictions, including Ireland, Luxembourg, Switzerland and the U.K. Deferred income taxes result from temporary differences between the amount of assets and liabilities recognized for financial reporting and tax purposes. The components of the net deferred tax (liability) asset at the end of each fiscal year were as follows: December 29, 2017 December 30, 2016 Deferred tax assets: Accrued liabilities and reserves $ 62.7 $ 103.3 Inventories 22.3 36.5 Tax loss and credit carryforwards 1,734.5 1,173.7 Environmental liabilities 17.0 28.5 Rebate reserves 1.6 48.0 Expired product 7.5 9.7 Postretirement benefits 14.0 47.5 Federal and state benefit of uncertain tax positions and interest 11.3 17.2 Share-based compensation 23.6 26.1 Intangible assets 575.1 383.2 Other 16.0 — 2,485.6 1,873.7 Deferred tax liabilities: Property, plant and equipment (47.0 ) (110.9 ) Intangible assets (181.0 ) (759.2 ) Interest-bearing deferred tax obligations (553.5 ) (1,801.4 ) Investment in partnership (108.8 ) (173.6 ) Other — (2.0 ) (890.3 ) (2,847.1 ) Net deferred tax asset (liability) before valuation allowances 1,595.3 (973.4 ) Valuation allowances (2,267.9 ) (1,398.3 ) Net deferred tax liability $ (672.6 ) $ (2,371.7 ) The deferred tax asset valuation allowances of $2,267.9 million and $1,398.3 million at December 29, 2017 and December 30, 2016, respectively, relate primarily to the uncertainty of the utilization of certain deferred tax assets, driven by non-U.K. net operating losses, credits and intangible assets. The Company believes that it will generate sufficient future taxable income to realize the tax benefits related to the remaining net deferred tax assets. The increase in tax loss and credit carryforwards and valuation allowances are primarily related to statutory deductions associated with internal transactions. Deferred taxes are reported in the following consolidated balance sheet captions in the amounts shown: December 29, 2017 December 30, 2016 Other assets $ 16.4 $ 26.4 Deferred income taxes (non-current liability) (689.0 ) (2,398.1 ) Net deferred tax liability $ (672.6 ) $ (2,371.7 ) Non-current deferred tax liability decreased from $2,398.1 million at December 30, 2016 to $689.0 million at December 29, 2017 , primarily due to $1,122.3 million of decreases associated with the Reorganization, $444.8 million of decreases associated with the TCJA’s reduction of the U.S. federal corporate statutory tax rate from 35% to 21%, $270.6 million of decreases associated with the payment of internal installment sale obligations and $63.6 million of decreases associated with the amortization of intangibles. These decreases are partially offset by $47.0 million of increases related to reductions of deferred tax assets associated with rebate reserves, $38.9 million of increases related to the divestiture of the Intrathecal Therapy business, $37.5 million of increases related to reductions of deferred tax assets associated with legal settlements, $29.7 million of increases related to recent acquisitions, $29.6 million of increases related to reductions of deferred tax assets associated with the termination and settlement of the Company's funded U.S. pension plans and $9.5 million of net increases related to operational activity. The Company refined its acquisition accounting estimate associated with the measurement of its acquired Stratatech net deferred tax liabilities in fiscal 2017, resulting in a decrease to the acquired net deferred tax liabilities from $24.3 million to $22.1 million prior to recording the impact from the TCJA. The InfaCare Acquisition resulted in a net deferred tax liability increase of $8.7 million prior to recording the impact from the TCJA. Significant components of this include $13.8 million of net deferred tax liabilities associated with intangibles partially offset by $4.7 million of deferred tax assets associated with non U.K. net operating losses. The Ocera Acquisition resulted in a net deferred tax liability increase of $23.2 million prior to recording the impact from the TCJA, which is primarily associated with intangibles. The divestiture of the Intrathecal Therapy Business was completed on March 17, 2017. This divestiture resulted in a net deferred tax liability increase of $38.9 million prior to recording the impact from the TCJA. Significant components of this increase include an increase of $56.4 million of deferred tax liability associated with future consideration, a decrease of $2.3 million of deferred tax asset associated with net operating losses, a decrease of $16.6 million of deferred tax liability associated with intangibles, an increase of $2.7 million of deferred tax asset associated with committed product development, and an increase of $0.5 million of other net deferred tax assets. At December 29, 2017 , the Company had approximately $1,604.0 million of net operating loss carryforwards in certain non-U.K. jurisdictions measured at the applicable statutory rates, of which $1,489.9 million have no expiration and the remaining $114.1 million will expire in future years through 2038 . As a result of the TCJA, the Company's Non-U.K. net operating losses decreased by $6.2 million . The Company had $106.4 million of U.K. net operating loss carryforwards measured at the applicable statutory rates at December 29, 2017 , which have no expiration date. At December 29, 2017 the Company also had $24.1 million of tax credits available to reduce future income taxes payable, primarily in jurisdictions within the U.S., of which $2.4 million have no expiration and the remainder expire during fiscal 2017 through 2038 . As of December 29, 2017 , there are no remaining cumulative undistributed earnings of the Company's subsidiaries that may be subject to tax. The net decrease in such undistributed earnings was attributable to the removal of the earnings for the entities reclassified to discontinued operations, undistributed earnings associated with income and losses attributed to the current year activity, and a reduction of the remaining cumulative undistributed earnings pursuant to the TCJA. The Company has preliminarily evaluated the impact of the TCJA with respect to the one-time tax imposed upon the deemed repatriation of undistributed earnings and estimated that no tax will be imposed upon the Company under such provisions. In fiscal 2017, the Company early adopted ASU 2016-16 utilizing the modified retrospective basis adoption method, with a cumulative-effect adjustment directly to retained earnings as of the beginning of the period for $75.0 million with an offsetting decrease of $67.2 million to other assets and a $7.8 million decrease to prepaid expenses on its consolidated balance sheets. The prior periods were not restated. In fiscal 2017, the Company adopted ASU 2016-09 and recorded an adjustment to retained earnings of $2.9 million to recognize net operating loss carryforwards, net of a valuation allowance, attributable to excess tax benefits on stock compensation that had not been previously recognized in additional paid-in capital.

Earnings (Loss) per Share

Earnings (Loss) per Share	12 Months Ended
	Dec. 29, 2017
Earnings (Loss) per Share [Abstract]
Earnings (Loss) per Share	9. Earnings (Loss) per Share Basic earnings (loss) per share is computed by dividing net income by the number of weighted-average shares outstanding during the period. Diluted earnings (loss) per share was computed using the weighted-average shares outstanding and, if dilutive, potential ordinary shares outstanding during the period. Potential ordinary shares represent the incremental ordinary shares issuable for restricted share units and share option exercises. The Company calculated the dilutive effect of outstanding restricted share units and share options on earnings (loss) per share by application of the treasury stock method. In fiscal 2015 and years prior, basic and diluted earnings (loss) per share were computed using the two-class method. The two-class method is an earnings allocation that determines earnings per share for each class of common stock and participating securities according to dividends declared and participation rights in undistributed earnings. The Company’s restricted stock awards, issued in conjunction with the acquisition of Questcor in August 2014 ("the Questcor Acquisition"), were considered participating securities as holders were entitled to receive non-forfeitable dividends during the vesting term. Diluted earnings per share included securities that could potentially dilute basic earnings per share during a reporting period, for which the Company includes all share-based compensation awards other than participating securities. Dilutive securities, including participating securities, are not included in the computation of loss per share when the Company reports a net loss from continuing operations as the impact would be anti-dilutive. Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Earnings (loss) per share numerator: Income (loss) from continuing operations attributable to common shareholders before allocation of earnings to participating securities $ 1,771.2 $ 489.0 $ 236.6 $ (176.8 ) Less: earnings allocated to participating securities — — 2.0 — Income (loss) from continuing operations attributable to common shareholders, after earnings allocated to participating securities 1,771.2 489.0 234.6 (176.8 ) Income from discontinued operations 363.2 154.7 88.1 23.6 Less: earnings from discontinued operations allocated to participating securities — — 0.7 — Income from discontinued operations attributable to common shareholders, after allocation of earnings to participating securities 363.2 154.7 87.4 23.6 Net income (loss) attributable to common shareholders, after allocation of earnings to participating securities $ 2,134.4 $ 643.7 $ 322.0 $ (153.2 ) Earnings (loss) per share denominator: Weighted-average shares outstanding - basic 97.7 110.6 115.8 105.7 Impact of dilutive securities 0.2 0.9 1.4 — Weighted-average shares outstanding - diluted 97.9 111.5 117.2 105.7 Basic earnings (loss) per share attributable to common shareholders: Income (loss) from continuing operations $ 18.13 $ 4.42 $ 2.03 $ (1.67 ) Income from discontinued operations 3.72 1.40 0.75 0.22 Net income (loss) attributable to common shareholders $ 21.85 $ 5.82 $ 2.78 $ (1.45 ) Diluted earnings (loss) per share attributable to common shareholders: Income (loss) from continuing operations $ 18.09 $ 4.39 $ 2.00 $ (1.67 ) Income from discontinued operations 3.71 1.39 0.75 0.22 Net income (loss) attributable to common shareholders $ 21.80 $ 5.77 $ 2.75 $ (1.45 ) The computation of diluted earnings per share for fiscal 2017 , 2016 , 2015 and the three months ended December 30, 2016, excludes approximately 4.2 million , 1.7 million , 0.1 million and 2.4 million , respectively, of equity awards because the effect would have been anti-dilutive. As the Company incurred a net loss in the three months ended December 30, 2016, there was no allocation of the undistributed loss to participating securities because the effect would have been anti-dilutive to basic and diluted earnings per share.

Inventories

Inventories	12 Months Ended
	Dec. 29, 2017
Inventory, Net [Abstract]
Inventories	10. Inventories Inventories are comprised of the following at the end of each period: December 29, December 30, Raw materials and supplies $ 70.0 $ 72.6 Work in process 167.1 178.4 Finished goods 103.3 99.7 Inventories $ 340.4 $ 350.7

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 29, 2017
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	11. Property, Plant and Equipment The gross carrying amount and accumulated depreciation of property, plant and equipment at the end of each period was as follows: December 29, 2017 December 30, 2016 Land $ 44.0 $ 46.9 Buildings 355.5 291.1 Capitalized software 109.0 87.2 Machinery and equipment 1,123.8 1,052.0 Construction in process 209.7 202.2 1,842.0 1,679.4 Less: accumulated depreciation (875.2 ) (797.9 ) Property, plant and equipment, net $ 966.8 $ 881.5 Depreciation expense, including amounts related to capitalized leased assets, for continuing operations was as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Depreciation expense $ 113.8 $ 113.3 $ 90.8 $ 27.5

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 29, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	12. Goodwill and Intangible Assets The changes in the carrying amount of goodwill by segment were as follows: December 29, 2017 December 30, 2016 Gross Carrying amount Accumulated Impairment Gross Carrying amount Accumulated Impairment Specialty Brands $ 3,482.7 $ 0.0 $ 3,498.1 $ 0.0 Specialty Generics 207.0 (207.0 ) 207.0 (207.0 ) Total $ 3,689.7 $ (207.0 ) $ 3,705.1 $ (207.0 ) During the fiscal year ended December 29, 2017, the gross carrying value of goodwill in the Specialty Brands segment decreased by $15.4 million . The decrease was primarily attributable to the sale of the Intrathecal Therapy business to Piramal for which $49.8 million of goodwill was ascribed and was factored into the gain on sale of the business. The decrease was partially offset by $25.1 million from the Ocera Acquisition and $11.4 million from the InfaCare Acquisition. The remaining change in goodwill was related to a purchase accounting adjustment for the Stratatech Acquisition primarily attributable to changes in deferred tax balances. Goodwill Impairment Analysis Fiscal Year ended December 29, 2017 The Company performed its annual goodwill impairment analysis for the Specialty Brands reporting unit as of the first day of the fourth quarter. For purposes of assessing impairment of goodwill for the Specialty Brands reporting unit, the Company made various assumptions regarding estimated future cash flows, discount rate and other factors in determining the respective fair value of the reporting unit using the income approach. These assumptions resulted in a fair value of the Specialty Brands reporting unit in excess of its net book value. The fair value of the Specialty Brands reporting unit was assessed for reasonableness by aggregating the fair values of the Company’s businesses and comparing this to its market capitalization with a control premium. Based upon the Company’s annual assessment, no goodwill impairment was identified. During the three months ended December 29, 2017, the Company experienced a substantial decline in its market capitalization, providing an indication that goodwill may be impaired at December 29, 2017. The decline in the Company’s market capitalization was driven by a decrease in its share price. The Company believes that its share price has been adversely affected most notably by patient withdrawal issues impacting net sales of H.P. Acthar Gel, ongoing Inomax patent litigation, uncertainty regarding the perceived value of its various pipeline products and an incomplete understanding of its complex income tax structure. In response to the decline in the Company's market capitalization, the annual valuation was updated and the Company determined that there was no goodwill impairment at December 29, 2017. The projections used in both the annual and the year ended December 29, 2017 valuations for the Specialty Brands reporting unit include management’s best estimate of long-term revenue and operating income. The Company's projections of future cash flows were discounted based on a weighted average cost of capital of 12.5% , for both valuations, that was determined from relevant market comparisons, adjusted upward for specific reporting unit risks. A terminal value growth rate was applied to the terminal year cash flows, representing the Company's estimate of stable, sustainable growth. The fair value of the Specialty Brands reporting unit represents the sum of the discounted cash flows from the discrete period and the terminal year cash flows. These assumptions resulted in a fair value of the Specialty Brands reporting unit in excess of its net book value by a mid-single digits in both valuations. The fair value of the Specialty Brands reporting unit was assessed for reasonableness by aggregating the fair value of the Company’s businesses and comparing this to its market capitalization with a control premium and consideration of the aforementioned adverse effects the Company believes have impacted its share price. Should the Specialty Brands reporting unit fail to experience growth, revise its long-term projections for its products downward or market conditions dictate utilization of a higher discount rate, the Specialty Brands reporting unit could be subject to impairment in future periods. In addition, the Company will continue to assess the impact of its market capitalization. It is possible that if the Company's market capitalization decline is sustained, such decline could result in an impairment of goodwill and other long-lived assets associated with its reporting units. The Three Months Ended December 30, 2016 The Specialty Generics reporting unit has experienced customer consolidation and increased competition that have and are expected to result in further downward pressure to net sales and operating income in this reporting unit. During the three months ended December 30, 2016, the FDA approved new products that are expected to compete with the Company's methylphenidate HCI extended-release tablets USP (CII) ("Methylphenidate ER") products and that one competitor launched their Methylphenidate ER products. Additional products expected to compete with the Company's Methylphenidate ER products were launched during fiscal 2017. All of these products have a class AB rating compared with the class BX rating on the Company's Methylphenidate ER products. It is uncertain how these product approvals may impact the FDA's withdrawal proceedings associated with the Company's Methylphenidate ER products. The Company determined that these events represented a triggering event and the Company performed an assessment of the goodwill associated with the Specialty Generics reporting unit as of December 30, 2016. The Company's projections in the Specialty Generics reporting unit included long-term net sales and operating income at lower than historical levels primarily attributable to customer consolidation and increased competition, including the competition effects on Methylphenidate ER. The Company utilized a weighted average cost of capital of 9.5% which reflects the Company's risk premium associated with the projected cash flows. These assumptions resulted in a fair value of the Specialty Generics reporting unit that was less than its net book value. As this impairment analysis was performed prior to the Company's adoption of ASU 2017-04 in fiscal 2017, the Company performed step two of the goodwill impairment test and recognized a $207.0 million goodwill impairment in the Specialty Generics segment. Intangible Assets The gross carrying amount and accumulated amortization of intangible assets at the end of each period were as follows: December 29, 2017 December 30, 2016 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Amortizable: Completed technology $ 9,882.8 $ 2,260.8 $ 10,028.7 $ 1,617.1 License agreements 177.1 121.1 177.1 112.7 Trademarks 82.1 14.5 82.1 10.9 Customer relationships 29.5 12.2 27.6 8.4 Other 8.6 8.6 6.7 6.7 Total $ 10,180.1 $ 2,417.2 $ 10,322.2 $ 1,755.8 Non-Amortizable: Trademarks $ 35.0 $ 35.0 In-process research and development 577.1 399.1 Total $ 612.1 $ 434.1 The Company recorded impairment charges totaling $63.7 million in fiscal 2017 related to the Raplixa intangible asset and $16.9 million in fiscal 2016 related to certain Specialty Brands in-process research and development intangible assets acquired as part of the CNS Therapeutics acquisition in fiscal 2013. In both fiscal 2017 and 2016, the valuation method used to approximate fair value was based on the estimated discounted cash flows for the respective asset. The Raplixa impairment charge resulted from the lower than previously anticipated commercial opportunities for the product, while the CNS Therapeutics IPR&D impairment charge resulted from delays in anticipated FDA approval, higher than expected development costs and lower than previously anticipated commercial opportunities. Finite-lived intangible asset amortization expense within continuing operations is as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Amortization expense $ 694.5 $ 700.1 $ 550.3 $ 175.7 The estimated aggregate amortization expense on intangible assets owned by the Company is expected to be as follows: Fiscal 2018 $ 681.8 Fiscal 2019 681.4 Fiscal 2020 681.1 Fiscal 2021 680.9 Fiscal 2022 553.9

Debt

Debt	12 Months Ended
	Dec. 29, 2017
Debt Disclosure [Abstract]
Debt	13. Debt Debt was comprised of the following at the end of each period: December 29, 2017 December 30, 2016 Principal Unamortized Discount and Debt Issuance Costs Principal Unamortized Discount and Debt Issuance Costs Current maturities of long-term debt: Variable-rate receivable securitization due July 2017 $ — $ — $ 250.0 $ 0.3 3.50% notes due April 2018 300.0 0.2 — — Term loans due March 2021 — — 20.0 0.3 4.00% term loan due February 2022 — — 1.0 — Term loan due September 2024 14.0 0.3 — — Capital lease obligation and vendor financing agreements 0.2 — 0.8 — Total current debt 314.2 0.5 271.8 0.6 Long-term debt: 3.50% notes due April 2018 — — 300.0 0.9 4.875% notes due April 2020 700.0 5.7 700.0 8.2 Variable-rate receivable securitization due July 2020 200.0 0.7 — — Term loans due March 2021 — — 1,928.5 33.4 4.00% term loan due February 2022 — — 5.5 — 9.50% debentures due May 2022 10.4 — 10.4 — 5.75% notes due August 2022 884.0 9.5 884.0 11.6 8.00% debentures due March 2023 4.4 — 4.4 — 4.75% notes due April 2023 526.5 4.5 600.0 6.1 5.625% notes due October 2023 738.0 9.7 738.0 11.4 Term loan due September 2024 1,837.2 26.7 — — 5.50% notes due April 2025 692.1 9.0 695.0 10.2 Revolving credit facility 900.0 5.9 100.0 3.2 Total long-term debt 6,492.6 71.7 5,965.8 85.0 Total debt $ 6,806.8 $ 72.2 $ 6,237.6 $ 85.6 Mallinckrodt International Finance S.A. ("MIFSA") is a wholly-owned subsidiary of the Company. MIFSA functions as a holding company, established to own, directly or indirectly, substantially all of the operating subsidiaries of the Company, as well as to issue debt securities and to perform treasury operations. In April 2013, MIFSA issued $300.0 million aggregate principal amount of 3.50% senior unsecured notes due April 2018 and $600.0 million aggregate principal amount of 4.75% senior unsecured notes due April 2023 (collectively, "the Notes"). Mallinckrodt plc has fully and unconditionally guaranteed the Notes on an unsecured and unsubordinated basis. The Notes are subject to an indenture which contains covenants limiting the ability of MIFSA, its restricted subsidiaries (as defined in the Notes) and Mallinckrodt plc, as guarantor, to incur certain liens or enter into sale and lease-back transactions. It also restricts Mallinckrodt plc and MIFSA's ability to merge or consolidate with any other person or sell or convey all or substantially all of their assets to any one person. MIFSA may redeem all of the Notes at any time, and some of the Notes from time to time, at a redemption price equal to the principal amount of the Notes redeemed plus a make-whole premium. MIFSA will pay interest on the Notes semiannually in arrears on April 15 th and October 15 th of each year, which commenced on October 15, 2013. In August 2014, MIFSA and Mallinckrodt CB LLC ("MCB") ("the Issuers") issued $900.0 million aggregate principal amount of 5.75% senior unsecured notes due August 1, 2022 ("the 2022 Notes”). The 2022 Notes are guaranteed by Mallinckrodt plc and each of its subsidiaries that guarantee the obligations under the 2017 Facilities (as defined below). The 2022 Notes are subject to an indenture that contains certain customary covenants and events of default (subject in certain cases to customary grace and cure periods). The occurrence of an event of default under the indenture could result in the acceleration of the 2022 Notes and could cause a cross-default that could result in the acceleration of other indebtedness of Mallinckrodt plc and its subsidiaries. The Issuers may redeem some or all of the 2022 Notes prior to August 1, 2017 by paying a make-whole premium. The Issuers may redeem some or all of the 2022 Notes on or after August 1, 2017 at specified redemption prices. In addition, on or prior to August 1, 2017, the Issuers may redeem up to 40% of the aggregate principal amount of the 2022 Notes with the net proceeds of certain equity offerings. The Issuers are obligated to offer to repurchase the 2022 Notes at a price of (a) 101% of their principal amount plus accrued and unpaid interest, if any, as a result of certain change of control events and (b) 100% of their principal amount plus accrued and unpaid interest, if any, in the event of certain asset sales. These obligations are subject to certain qualifications and exceptions. MIFSA pays interest on the 2022 Notes semiannually in arrears on February 1 st and August 1 st of each year, which commenced on February 1, 2015. On April 15, 2015, MIFSA and MCB issued $700.0 million aggregate principal amount of 4.875% senior unsecured notes due April 15, 2020 ("the 2020 Notes") and $700.0 million aggregate principal amount of 5.50% senior unsecured notes due April 15, 2025 ("the 2025 Notes", and together with the 2020 Notes, the "Ikaria Notes"). The Ikaria Notes are guaranteed by Mallinckrodt plc and each of its subsidiaries that guarantee the obligations under the 2017 Facilities, which following the Ikaria Acquisition includes Compound Holdings II, Inc. (or its successors) and its U.S. subsidiaries. The Ikaria Notes are subject to an indenture that contains certain customary covenants and events of default (subject in certain cases to customary grace and cure periods). The occurrence of an event of default under the indenture could result in the acceleration of the Ikaria Notes and could cause a cross-default that could result in the acceleration of other indebtedness of the Company. The Issuers may redeem some or all of the (i) 2020 Notes prior to April 15, 2017 and (ii) 2025 Notes prior to April 15, 2020, in each case, by paying a “make-whole” premium. The Issuers may redeem some or all of the (i) 2020 Notes on or after April 15, 2017 and (ii) 2025 Notes on or after April 15, 2020, in each case, at specified redemption prices. In addition, on or prior to (i) April 15, 2017, in the case of the 2020 Notes, and (ii) April 15, 2018, in the case of the 2025 Notes, the Issuers may redeem up to 40% of the aggregate principal amount of the 2020 Notes or 2025 Notes, as the case may be, with the net proceeds of certain equity offerings. The Issuers are obligated to offer to repurchase (a) each series of Notes at a price of 101% of their principal amount plus accrued and unpaid interest, if any, as a result of certain change of control events and (b) the Notes at a price of 100% of their principal amount plus accrued and unpaid interest, if any, in the event of certain net asset sales. These obligations are subject to certain qualifications and exceptions. The Company pays interest on the Ikaria Notes semiannually on April 15 th and October 15 th of each year, which commenced on October 15, 2015. On September 24, 2015, in connection with the Therakos Acquisition, MIFSA and MCB issued $750.0 million aggregate principal amount of 5.625% senior unsecured notes due October 2023 (the “2023 Notes”). The Notes are guaranteed by Mallinckrodt plc and each of its subsidiaries under the 2017 Facilities, which following the Therakos Acquisition includes TGG Medical Solutions, Inc (or its successors). and its U.S. subsidiaries. The 2023 Notes are subject to an indenture that contains certain customary covenants and events of default (subject in certain cases to customary grace and cure periods). The occurrence of an event of default under the indenture could result in the acceleration of the 2023 Notes and could cause a cross-default that could result in the acceleration of other indebtedness of the Company. The Issuers may redeem some or all of the 2023 Notes on or after October 15, 2018 at specified redemption prices. In addition, on or prior to October 15, 2018, the Issuers may redeem up to 40% of the aggregate principal amount of the 2023 Notes with the net proceeds of certain equity offerings. The Issuers may also redeem all, but not less than all, of the Notes at any time at a price of 100% of their principal amount, plus accrued and unpaid interest, if any, in the event the Issuers become obligated to pay additional amounts as a result of changes affecting certain withholding tax laws applicable to payments on the Notes. The Issuers are obligated to offer to repurchase the 2023 Notes (a) at a price of 101% of their principal amount plus accrued and unpaid interest, if any, as a result of certain change of control events and (b) the 2023 Notes at a price of 100% of their principal amount plus accrued and unpaid interest, if any, in the event of certain net asset sales. These obligations are subject to certain qualifications and exceptions. The Company pays interest on the 2023 Notes semiannually on April 15 th and October 15 th of each year, which commenced on April 15, 2016. On February 28, 2017, MIFSA and MCB refinanced the March 2014 and August 2014 term loans, both of which were due in March 2021 ("the Existing Term Loans"). The refinanced term loans had an initial aggregate principal amount of $1,865.0 million , are due in September 2024 and bear interest at London Interbank Offered Rate ("LIBOR") plus 2.75% ("the 2017 Term Loan"). The 2017 Term Loan requires quarterly principal amortization payments in an amount equal to 0.25% of the original principal balance of the 2017 Term Loan, and may be reduced by making optional prepayments. The quarterly principal amortization is payable on the last day of each calendar quarter, which commenced on June 30, 2017, with the remaining balance due on September 24, 2024. The Company accounted for the term loan refinancing as a debt modification. As of December 29, 2017, the interest rate for the 2017 Term Loan was 4.44% , and outstanding principal under this agreement totaled approximately $1,851.2 million . In conjunction with the term loan refinancing, MIFSA and MCB replaced the existing revolving credit facility of $500.0 million due in March 2019 with a $900.0 million facility that matures on February 28, 2022 ("the 2017 Revolving Credit Facility"). The 2017 Revolving Credit Facility bears interest at LIBOR plus 2.25% . The 2017 Revolving Credit Facility reduced the letter of credit provision from $150.0 million to $50.0 million . Unused commitments on the 2017 Revolving Credit Facility are subject to an annual commitment fee, which was 0.275% as of December 29, 2017 , and the fee applied to outstanding letters of credit is based on the interest rate applied to borrowings. As of December 29, 2017 , there was $900.0 million in outstanding borrowings under the 2017 Revolving Credit Facility, the applicable interest rate was 3.94% as of December 29, 2017. The 2017 Revolving Credit Facility added certain wholly-owned subsidiaries of the Company as borrowers, in addition to MIFSA and MCB. The 2017 Term Loan and 2017 Revolving Credit Facility (collectively "the 2017 Facilities") are fully and unconditionally guaranteed by Mallinckrodt plc, certain of its direct or indirect wholly-owned U.S. subsidiaries and each of its direct or indirect wholly-owned subsidiaries that owns directly or indirectly any wholly-owned U.S. subsidiaries and certain of its other subsidiaries (collectively, "the Guarantors"). The 2017 Facilities are secured by a security interest in certain assets of MIFSA, MCB and the Guarantors. The 2017 Facilities contain customary affirmative and negative covenants, which include, among other things, restrictions on the Company's ability to declare or pay dividends, create liens, incur additional indebtedness, enter into sale and lease-back transactions, make investments, dispose of assets and merge or consolidate with any other person. As a result of the 2017 Facilities financing transaction and the write-off of certain deferred financing costs associated with an $83.5 million payment on the Existing Term Loans, the Company recorded a $10.0 million charge included within the other expense line in the consolidated statement of income. On July 28, 2017, Mallinckrodt Securitization S.à r.l. ("Mallinckrodt Securitization"), a wholly owned special purpose subsidiary of the Company, entered into a $250.0 million accounts receivable securitization facility ("the Receivable Securitization") with a three year term. The Receivable Securitization was entered into upon the maturity of the original July 2017 Securitization. Mallinckrodt Securitization may, from time to time, obtain up to $250.0 million in third-party borrowings secured by certain receivables. The borrowings under the Receivable Securitization are to be repaid as the secured receivables are collected. Loans under the Receivable Securitization will bear interest (including facility fees) at a rate equal to one month LIBOR rate plus a margin of 0.9% . Unused commitments on the Receivables Securitization are subject to an annual commitment fee of 0.4% . The Receivable Securitization agreements contain customary representations, warranties, and affirmative and negative covenants. The size of the securitization facility may be increased to $300.0 million upon approval of the third-party lenders. As of December 29, 2017 , the applicable interest rate on outstanding borrowings under the Receivable Securitization was 2.46% and outstanding borrowings totaled $200.0 million . The aggregate amounts of debt, including the capital lease obligation, maturing during the next five fiscal years are as follows: Fiscal 2018 $ 314.2 Fiscal 2019 18.7 Fiscal 2020 918.7 Fiscal 2021 23.3 Fiscal 2022 1,813.0

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 29, 2017
Retirement Benefits [Abstract]
Retirement Plans	14. Retirement Plans Pension Plan Termination On March 31, 2016, the Company terminated six of its previously frozen U.S. pension plans. During fiscal 2017, approximately $212.9 million of obligations and corresponding pension assets were transferred to a third party for settlement of the terminated pension plans through the purchase of annuity contracts. As a result of the settlement, the Company made a $62.3 million cash contribution to the terminated plans and recognized a $70.5 million charge included within SG&A expense during fiscal 2017. Defined Benefit Plans The Company sponsors a number of defined benefit retirement plans covering certain of its U.S. employees and non-U.S. employees. As of December 29, 2017 , U.S. plans represented 39% of the Company's remaining projected benefit obligation. The Company generally does not provide postretirement benefits other than retirement plan benefits for its employees; however, certain of the Company's U.S. employees participate in postretirement benefit plans that provide medical benefits. These plans are unfunded. The net periodic benefit cost (credit) for the Company's pension and postretirement benefit plans was as follows: Pension Benefits Fiscal Year Ended Three Months Ended December 29, September 30, September 25, December 30, Service cost $ 1.4 $ 1.8 $ 2.4 $ 0.8 Interest cost 2.3 13.2 14.5 2.0 Expected return on plan assets (1.3 ) (16.7 ) (18.9 ) (2.3 ) Amortization of net actuarial loss 2.7 11.3 9.2 3.5 Amortization of prior service cost 0.2 — — 0.1 Loss on plan settlements 71.1 8.1 5.9 45.0 Curtailment gain (1.0 ) — — — Net periodic benefit cost $ 75.4 $ 17.7 $ 13.1 $ 49.1 Postretirement Benefits Fiscal Year Ended Three Months Ended December 29, September 30, September 25, December 30, Service cost $ — $ 0.1 $ 0.1 $ 0.1 Interest cost 1.7 2.0 1.9 0.4 Amortization of prior service credit (2.0 ) (2.1 ) (4.0 ) (0.5 ) Gain on plan settlements (0.9 ) — — — Net periodic benefit credit $ (1.2 ) $ — $ (2.0 ) $ — The following table represents the changes in benefit obligations, plan assets and the net amounts recognized on the consolidated balance sheets for pension and postretirement benefit plans at the end of each period: Pension Benefits Postretirement Benefits December 29, December 30, September 30, December 29, December 30, September 30, Change in benefit obligations: Projected benefit obligations at beginning of year $ 257.4 $ 409.1 $ 375.5 $ 47.5 $ 50.8 $ 52.2 Service cost 1.4 0.8 1.8 — 0.1 0.1 Interest cost 2.3 2.0 13.2 1.7 0.4 2.0 Actuarial (gain) loss (9.0 ) (23.2 ) 65.5 0.2 (2.8 ) 0.5 Benefits and administrative expenses paid (9.4 ) (5.3 ) (20.1 ) (2.9 ) (1.0 ) (4.0 ) Plan settlements (217.0 ) (125.9 ) (26.5 ) (0.9 ) — — Plan curtailments and amendments — — (0.4 ) — — — Net transfer in — 1.1 — — — — Currency translation 2.1 (1.2 ) 0.1 — — — Projected benefit obligations at end of year $ 27.8 $ 257.4 $ 409.1 $ 45.6 $ 47.5 $ 50.8 Change in plan assets: Fair value of plan assets at beginning of year $ 161.0 $ 309.5 $ 309.9 $ — $ — $ — Actual return on plan assets 0.3 (18.1 ) 29.5 — — — Employer contributions 68.0 0.8 16.7 2.9 1.0 4.0 Benefits and administrative expenses paid (9.4 ) (5.3 ) (20.1 ) (2.9 ) (1.0 ) (4.0 ) Plan settlements (217.0 ) (125.9 ) (26.5 ) — — — Net transfer out (2.9 ) — — — — — Fair value of plan assets at end of year $ — $ 161.0 $ 309.5 $ — $ — $ — Funded status at end of year $ (27.8 ) $ (96.4 ) $ (99.6 ) $ (45.6 ) $ (47.5 ) $ (50.8 ) Pension Benefits Postretirement Benefits December 29, December 30, December 29, December 30, Amounts recognized on the consolidated balance sheet: Non-current assets $ — $ 1.4 $ — $ — Current liabilities (2.4 ) (5.5 ) (3.9 ) (4.2 ) Non-current liabilities (25.4 ) (92.3 ) (41.7 ) (43.3 ) Net amount recognized on the consolidated balance sheet $ (27.8 ) $ (96.4 ) $ (45.6 ) $ (47.5 ) Amounts recognized in accumulated other comprehensive income consist of: Net actuarial loss $ (8.6 ) $ (89.7 ) $ (3.0 ) $ (2.8 ) Prior service (cost) credit (0.5 ) 0.4 10.2 12.3 Net amount recognized in accumulated other comprehensive income $ (9.1 ) $ (89.3 ) $ 7.2 $ 9.5 The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost (credit) in fiscal 2018 are as follows: Pension Benefits Postretirement Benefits Amortization of net actuarial loss $ (0.5 ) $ (0.1 ) Amortization of prior service (cost) credit (0.1 ) 2.1 Additional information related to pension plans is as follows: December 29, December 30, Pension plans with accumulated benefit obligations in excess of plan assets: Accumulated benefit obligation $ 27.3 $ 251.2 Fair value of plan assets — 153.8 The accumulated benefit obligation and fair value of plan assets for pension plans with projected benefit obligations in excess of plan assets do not significantly differ from the amounts in the table above since all of the Company's pension plans are frozen. Actuarial Assumptions Weighted-average assumptions used each period to determine net periodic benefit cost for the Company's pension plans are as follows: U.S. Plans Non-U.S. Plans Fiscal Year Ended Three Months Ended Fiscal Year Ended Three Months Ended 2017 2016 2015 December 30, 2016 2017 2016 2015 December 30, 2016 Discount rate 3.0 % 3.9 % 3.8 % 2.2 % 1.8 % 2.0 % 2.4 % 1.3 % Expected return on plan assets 3.5 % 5.8 % 6.0 % 3.5 % — % 2.0 % 2.0 % — % Rate of compensation increase — % — % — % — % 2.5 % — % — % — % Weighted-average assumptions used each period to determine benefit obligations for the Company's pension plans are as follows: U.S. Plans Non-U.S. Plans Fiscal Year Ended Three Months Ended Fiscal Year Ended Three Months Ended 2017 2016 2015 December 30, 2016 2017 2016 2015 December 30, 2016 Discount rate 3.3 % 2.3 % 3.9 % 3.0 % 1.9 % 1.3 % 2.4 % 1.8 % Rate of compensation increase — % — % — % — % 2.5 % — % — % 0.3 % For the Company's unfunded U.S. plans, the discount rate is based on the market rate for a broad population of AA-rated (Moody's or S&P) corporate bonds over $250.0 million . For the Company's U.S. plans that were funded in prior periods, the discount rate was based on the estimated final settlement discount rates based on quotes received from a group of well-rated insurance carriers who are active in the single premium group annuity marketplace. The group of insurance carriers are rated A or better by AM best. Prior to the settlement of the funded U.S. plans in fiscal 2017, the Company determined the expected return on pension plan assets, through its considerations of the relative weighting of plan assets by class and individual asset class performance expectations as provided by external advisors in reaching conclusions on appropriate assumptions. The investment strategy for the pension plans was to obtain a long-term return on plan assets that was consistent with the level of investment risk that was considered appropriate. Investment risks and returns were reviewed regularly against benchmarks to ensure objectives were being met. The weighted-average discount rate used to determine net periodic benefit cost and obligations for the Company's postretirement benefit plans are as follows: Fiscal Year Three Months Ended 2017 2016 2015 December 30, 2016 Net periodic benefit cost 3.7 % 4.0 % 3.6 % 3.2 % Benefit obligations 3.4 % 3.2 % 3.9 % 3.8 % Healthcare cost trend assumptions for postretirement benefit plans are as follows: December 29, December 30, Healthcare cost trend rate assumed for next fiscal year 6.9 % 6.9 % Rate to which the cost trend rate is assumed to decline 4.5 % 4.5 % Fiscal year the ultimate trend rate is achieved 2038 2038 A one-percentage-point change in assumed healthcare cost trend rates would have the following effects: One-Percentage-Point Increase One-Percentage-Point Decrease Effect on total of service and interest cost $ — $ — Effect on postretirement benefit obligation 0.2 (0.4 ) Plan Assets As of December 29, 2017, the Company had no pension plan assets as a result of the termination and settlement of the Company's funded U.S. plans in fiscal 2017. Prior to, and in anticipation of, the settlement of these defined benefit pension plans, the asset allocation at December 30, 2016 was concentrated in debt securities, in an attempt to mitigate fluctuations in both interest rates and the equity markets. The following table provides a summary of plan assets held by the Company's pension plans and the respective weighted-average asset allocations as of December 30, 2016 : December 30, 2016 (1) Weighted-Average Asset Allocation Equity Securities: U.S. large cap $ 1.7 1 % Debt securities: Diversified fixed income funds (2) 148.3 92 Cash and cash equivalents 11.0 7 Total $ 161.0 100 % (1) All plan assets were measured at fair value on a recurring basis and were categorized as Level 1 with quoted prices in active markets for identical assets. (2) Diversified fixed income funds consist of U.S. Treasury bonds, mortgage-backed securities, corporate bonds, asset-backed securities and U.S. agency bonds. Equity securities. Equity securities primarily consisted of mutual funds with underlying investments in foreign equity and domestic equity markets. The fair value of these investments were based on net asset value of the units held in the respective fund, which are determined by obtaining quoted prices on nationally recognized securities exchanges (level 1). Debt securities. Debt securities were primarily invested in mutual funds with underlying fixed income investments in U.S. government and corporate debt, U.S. dollar denominated foreign government and corporate debt, asset-backed securities, mortgage-backed securities and U.S. agency bonds. The fair value of these investments were based on the net asset value of the units held in the respective fund which were determined by obtaining quoted prices on nationally recognized securities exchanges. Cash and cash equivalents. Cash and cash equivalents were invested in a money market mutual fund, the fair value of which was determined by obtaining quoted prices on nationally recognized securities exchanges (level 1). Mallinckrodt shares were not a direct investment of the Company's pension funds; however, the pension funds might have indirectly included Mallinckrodt shares. The aggregate amount of the Mallinckrodt shares were not material relative to the total pension fund assets. Contributions The Company's funding policy is to make contributions in accordance with the laws and customs of the various countries in which the Company operates, as well as to make discretionary voluntary contributions from time to time. In fiscal 2017, 2016 and the three months ended December 30, 2016, the Company made $68.0 million , $16.7 million and $0.8 million in contributions, respectively, to the Company's pension plans. The fiscal 2017 contribution included additional payments to settle the terminated plans. Expected Future Benefit Payments Benefit payments expected to be paid, reflecting future expected service as appropriate, are as follows: Pension Benefits Postretirement Benefits Fiscal 2018 $ 2.4 $ 3.9 Fiscal 2019 1.8 3.7 Fiscal 2020 1.8 3.5 Fiscal 2021 1.7 3.3 Fiscal 2022 1.6 3.2 Fiscal 2023 - 2027 7.5 14.2 Defined Contribution Retirement Plans The Company maintains one active tax-qualified 401(k) retirement plan and one active non-qualified deferred compensation plan in the U.S. The 401(k) retirement plan provides for an automatic Company contribution of three percent of an eligible employee's pay, with an additional Company matching contribution generally equal to 50% of each employee's elective contribution to the plan up to six percent of the employee's eligible pay. The deferred compensation plan permits eligible employees to defer a portion of their compensation. Total defined contribution expense related to continuing operations was $25.2 million , $25.3 million , $22.1 million and $4.2 million for fiscal 2017 , 2016 , 2015 and the three months ended December 30, 2016, respectively. Rabbi Trusts and Other Investments The Company maintains several rabbi trusts, the assets of which are used to pay retirement benefits. The rabbi trust assets are subject to the claims of the Company's creditors in the event of the Company's insolvency. Plan participants are general creditors of the Company with respect to these benefits. The trusts primarily hold life insurance policies and debt and equity securities, the value of which is included in other assets on the consolidated balance sheets. Note 20 provides additional information regarding the debt and equity securities. The carrying value of the 124 life insurance contracts held by these trusts was $58.1 million and $59.9 million at December 29, 2017 and December 30, 2016 , respectively. These contracts had a total death benefit of $145.8 million and $150.7 million at December 29, 2017 and December 30, 2016 , respectively. However, there are outstanding loans against the policies amounting to $44.5 million and $44.0 million at December 29, 2017 and December 30, 2016 , respectively. The Company has insurance contracts which serve as collateral for certain of the Company's non-U.S. pension plan benefits, which totaled $8.8 million and $7.7 million at December 29, 2017 and December 30, 2016 , respectively. These amounts were also included in other assets on the consolidated balance sheets.

Equity Equity

Equity Equity	12 Months Ended
	Dec. 29, 2017
Equity [Abstract]
Stockholders' Equity Note Disclosure	15. Equity Preferred Shares Mallinckrodt is authorized to issue 500,000,000 preferred shares, par value of $0.20 per share, none of which were issued or outstanding at December 29, 2017 . Rights as to dividends, return of capital, redemption, conversion, voting and otherwise with respect to these shares may be determined by Mallinckrodt's Board of Directors on or before the time of issuance. In the event of the liquidation of the Company, the holders of any preferred shares then outstanding would, if issued on such terms that they carry a preferential distribution entitlement on liquidation, be entitled to payment to them of the amount for which the preferred shares were subscribed and any unpaid dividends prior to any payment to the ordinary shareholders. Share Repurchases On January 23, 2015, the Company's Board of Directors authorized a $300.0 million share repurchase program (the "January 2015 Program"), which was completed during fiscal 2016. On November 19, 2015, the Company's Board of Directors authorized a $500.0 million share repurchase program (the "November 2015 Program"), which was completed in the three months ended December 30, 2016. On March 16, 2016, the Company's Board of Directors authorized an additional $350.0 million share repurchase program (the "March 2016 Program"), which was completed during fiscal 2017. On March 1, 2017, the Company's Board of Directors authorized an additional $1.0 billion share repurchase program (the "March 2017 Program"), which commenced upon the completion of the March 2016 Program. The March 2017 Program has no time limit or expiration date, and the Company currently expects to fully utilize the program. March 2017 Repurchase Program March 2016 November 2015 Repurchase Program January 2015 Repurchase Program Number of Shares Amount Number of Shares Amount Number of Shares Amount Number of Shares Amount Authorized repurchase amount $ 1,000.0 $ 350.0 $ 500.0 $ 300.0 Repurchases: Fiscal 2015 — — — — — — 823,592 75.0 Fiscal 2016 — — — — 6,510,824 425.6 3,199,279 225.0 Three months ended December 30, 2016 — — 1,501,676 84.0 1,063,337 74.4 — — Fiscal 2017 13,490,448 380.6 5,366,741 266.0 — — — — Remaining amount available $ 619.4 $ — $ — $ — The Company also repurchases shares from certain employees in order to satisfy employee tax withholding requirements in connection with the vesting of restricted shares. In addition, the Company repurchases shares to settle certain option exercises. The Company spent $5.1 million , $2.3 million , $17.2 million and $0.4 million to acquire shares in connection with equity-based awards in fiscal 2017, 2016, 2015 and the three months ended December 30, 2016, respectively. Treasury Shares During December 2017, the Company canceled approximately 26.5 million treasury shares. Irish law requires a company's treasury share value to represent less than 10% of Company capital. The cancellation of treasury shares had a net zero impact on shareholders' equity as $5.3 million was reflected in both common stock and additional paid in capital.

Share Plans

Share Plans	12 Months Ended
	Dec. 29, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share Plans	16. Share Plans Total share-based compensation cost from continuing operations was $58.5 million , $41.4 million , $115.0 million and $10.6 million for fiscal 2017 , 2016 , 2015 and the three months ended December 30, 2016, respectively. These amounts are generally included within SG&A expenses in the consolidated statements of income. In conjunction with the Questcor Acquisition, Questcor equity awards were converted to Mallinckrodt equity awards which resulted in post-combination expense of $90.4 million in fiscal 2015, included in the above total share-based compensation, of which $80.6 million is included within SG&A expenses and $9.8 million is included within restructuring charges, net. The Company recognized a related tax benefit associated with this expense of $11.0 million , $13.1 million , $41.3 million and $3.6 million in fiscal 2017 , 2016 , 2015 and the three months ended December 30, 2016, respectively. During fiscal 2017, the $11.0 million tax benefit was comprised of $16.0 million associated with amortization and net stock exercises, partially offset by $5.0 million associated with U.S. Tax Reform re-measurement. Stock Compensation Plans Prior to the Separation, the Company adopted the 2013 Mallinckrodt Pharmaceuticals Stock and Incentive Plan ("the 2013 Plan"). The 2013 Plan provides for the award of share options, share appreciation rights, annual performance bonuses, long-term performance awards, restricted units, restricted shares, deferred share units, promissory shares and other share-based awards (collectively, "Awards"). The 2013 Plan provided for a maximum of 5.7 million common shares to be issued as Awards, subject to adjustment as provided under the terms of the 2013 Plan. In fiscal 2015, the Company amended the 2013 Plan and adopted the 2015 Mallinckrodt Pharmaceuticals Stock and Incentive Plan ("the 2015 Plan"). The 2015 Plan provides for a maximum of 17.8 million common shares to be issued as Awards (an incremental 12.1 million Awards from the 2013 Plan subject to issuance), subject to adjustment as provided under the terms of the 2015 Plan. As of December 29, 2017 , all equity awards held by the Company's employees were either converted from Covidien equity awards at the Separation, converted from Questcor equity awards, or granted under the 2013 Plan or 2015 Plan. Share options. Share options are granted to purchase the Company's ordinary shares at prices that are equal to the fair market value of the shares on the date the share option is granted. Share options generally vest in equal annual installments over a period of four years and expire ten years after the date of grant. The grant-date fair value of share options, adjusted for estimated forfeitures, is recognized as expense on a straight-line basis over the requisite service period, which is generally the vesting period. Forfeitures are estimated based on historical experience. Share option activity and information is as follows: Share Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding at September 26, 2014 3,526,789 $ 36.84 Granted 635,567 102.20 Exercised (1,132,778 ) 29.79 Expired/Forfeited (243,135 ) 58.00 Outstanding at September 25, 2015 2,786,443 52.76 Granted 1,248,828 72.44 Exercised (413,830 ) 32.76 Expired/Forfeited (199,585 ) 72.65 Outstanding at September 30, 2016 3,421,856 61.17 Granted 3,742 60.01 Exercised (16,382 ) 36.42 Expired/Forfeited (22,522 ) 70.82 Outstanding at December 30, 2016 3,386,694 61.24 Granted 1,719,532 51.57 Exercised (113,605 ) 47.74 Expired/Forfeited (348,637 ) 68.08 Outstanding at December 29, 2017 4,643,984 57.78 6.9 $ 0.2 Vested and non-vested expected to vest as of December 29, 2017 3,882,733 60.62 7.5 $ (0.6 ) Exercisable at December 29, 2017 1,944,709 52.19 4.7 0.2 As of December 29, 2017 , there was $37.7 million of total unrecognized compensation cost related to non-vested share option awards, which is expected to be recognized over a weighted-average period of 2.5 years . The grant-date fair value of share options has been estimated using the Black-Scholes pricing model. Use of a valuation model requires management to make certain assumptions with respect to selected model inputs. The expected volatility assumption is based on the historical and implied volatility of the Company's peer group with similar business models. The expected life assumption is based on the contractual and vesting term of the share option, employee exercise patterns and employee post-vesting termination behavior. The expected annual dividend per share is based on the Company's current intentions regarding payment of cash dividends. The risk-free interest rate is based on U.S. Treasury zero-coupon issues with a remaining term equal to the expected life assumed at the date of grant. The weighted-average assumptions used in the Black-Scholes pricing model for shares granted in fiscal 2017 , 2016 , 2015 and the three months ended December 30, 2016, along with the weighted-average grant-date fair value, were as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Expected share price volatility 36 % 31 % 29 % 35 % Risk-free interest rate 2.00 % 1.74 % 1.72 % 1.23 % Expected annual dividend per share — % — % — % — % Expected life of options (in years) 5.3 5.3 5.3 5.3 Fair value per option $ 18.36 $ 22.82 $ 30.08 $ 20.04 In fiscal 2017 , 2016 , 2015 and the three months ended December 30, 2016, the total intrinsic value of options exercised was $1.4 million , $15.3 million , $89.5 million and $0.3 million , respectively, and the related tax benefit was $0.5 million , $5.7 million , $33.1 million and $0.1 million , respectively. Restricted share units. Recipients of restricted share units ("RSUs") have no voting rights and receive dividend equivalent units which vest upon the vesting of the related shares. RSUs generally vest in equal annual installments over a period of four years . Restrictions on RSUs lapse upon normal retirement, death or disability of the employee. The grant-date fair value of RSUs, adjusted for estimated forfeitures, is recognized as expense on a straight-line basis over the service period. The fair market value of RSUs granted after the Conversion is determined based on the market value of the Company's shares on the date of grant for periods after the Separation. RSU activity is as follows: Shares Weighted-Average Non-vested at September 26, 2014 589,222 $ 47.88 Granted 273,733 105.68 Vested (219,189 ) 49.84 Expired/Forfeited (71,272 ) 68.15 Non-vested at September 25, 2015 572,494 73.45 Granted 615,074 70.10 Vested (193,849 ) 69.27 Expired/Forfeited (99,260 ) 79.95 Non-vested at September 30, 2016 894,459 70.40 Granted 36,731 69.08 Exercised (30,919 ) 47.54 Expired/Forfeited (16,809 ) 49.62 Non-vested at December 30, 2016 883,462 71.03 Granted 655,282 50.74 Exercised (263,189 ) 69.14 Expired/Forfeited (169,789 ) 68.57 Non-vested at December 29, 2017 1,105,766 60.08 The total fair value of Mallinckrodt RSU awards granted during fiscal 2017 was $50.7 million . The total vest date fair value of Mallinckrodt RSUs vested during fiscal 2017 was $69.1 million . As of December 29, 2017 , there was $42.0 million of total unrecognized compensation cost related to non-vested restricted share units granted. The cost is expected to be recognized over a weighted-average period of 2.4 years . Performance share units. Similar to recipients of RSUs, recipients of performance share units ("PSUs") have no voting rights and receive dividend equivalent units. The grant-date fair value of PSUs, adjusted for estimated forfeitures, is generally recognized as expense on a straight-line basis from the grant-date through the end of the performance period. The vesting of PSUs and related dividend equivalent units is generally based on various performance metrics and relative total shareholder return (total shareholder return for the Company as compared to total shareholder return of the PSU peer group), measured over a three -year performance period. The PSU peer group is comprised of various healthcare companies which attempts to replicate the Company’s mix of businesses. Depending on Mallinckrodt's relative performance during the performance period, a recipient of the award is entitled to receive a number of ordinary shares equal to a percentage, ranging from 0% to 200% , of the award granted. PSU activity is as follows (1) : Shares Weighted-Average Non-vested at September 26, 2014 72,740 $ 63.46 Granted 77,306 125.84 Forfeited (19,072 ) 92.05 Non-vested at September 25, 2015 130,974 96.05 Granted 145,192 83.00 Forfeited (9,521 ) 96.30 Non-vested at September 30, 2016 266,645 88.59 Forfeited (997 ) 154.42 Non-vested at December 30, 2016 265,648 88.51 Granted 348,963 51.73 Forfeited (48,606 ) 107.00 Vested (61,554 ) 62.65 Non-vested at December 29, 2017 504,451 64.44 (1) The number of shares disclosed within this table are at the target number of 100%. The Company generally uses the Monte Carlo model to estimate the probability of satisfying the performance criteria and the resulting fair value of PSU awards. The assumptions used in the Monte Carlo model for PSUs granted during each year were as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Expected stock price volatility 48 % 41 % 27 % 48 % Peer group stock price volatility 40 % 36 % 32 % 40 % Correlation of returns 17 % 24 % 14 % 17 % The weighted-average grant-date fair value per share of PSUs granted was $51.73 in fiscal 2017 . As of December 29, 2017 , there was $18.5 million of unrecognized compensation cost related to PSUs, which is expected to be recognized over a weighted-average period of 1.8 years. Restricted stock awards. Recipients of restricted stock awards ("RSAs") pertain solely to converted awards from the Questcor Acquisition, which were converted at identical terms to their original award. The converted RSAs maintain voting rights and a non-forfeitable right to receive dividends. RSAs are subject to accelerated vesting as prescribed by the terms of the original award based on a change in control, and substantially all of which vested over a thirteen month period of time from the date of the Questcor Acquisition. Restrictions on RSAs lapse upon normal retirement, death or disability of the employee. The grant-date fair value of RSAs, adjusted for estimated forfeitures, is recognized as expense on a straight-line basis over the service period. The weighted average grant-date fair value per share is $70.88 . Shares Non-vested at September 26, 2014 1,432,031 Vested (1,362,823 ) Forfeited (34,646 ) Non-vested at September 25, 2015 34,562 Vested (9,760 ) Forfeited (7,936 ) Non-vested at September 30, 2016 16,866 Vested (1,087 ) Forfeited (911 ) Non-vested at December 30, 2016 14,868 Vested (7,970 ) Forfeited (2,223 ) Non-vested at December 29, 2017 4,675 The total vest date fair value of Mallinckrodt restricted share awards vested during fiscal 2017 was $0.4 million . Employee Stock Purchase Plans Effective March 16, 2016, upon approval by the shareholders of Mallinckrodt, the Company adopted a new qualified Mallinckrodt Employee Stock Purchase Plan ("ESPP"). Substantially all full-time employees of the Company's U.S. subsidiaries and employees of certain qualified non-U.S. subsidiaries are eligible to participate in the ESPP. Eligible employees authorize payroll deductions to be made to purchase shares at 15% below the market price at the beginning or end of an offering period. Employees are eligible to authorize withholdings such that purchases of shares may amount to $25,000 of fair market value for each calendar year as prescribed by the Internal Revenue Code Section 423. Mallinckrodt has elected to deliver shares under the period by utilizing treasury stock accumulated by the Company. Prior to the first offering period of the ESPP (July 1, 2016), the Company maintained a non-qualified employee stock purchase plan ("the Old ESPP"). Substantially all full-time employees of the Company's U.S. subsidiaries and employees of certain qualified non-U.S. subsidiaries were eligible to participate in the Old ESPP. Eligible employees authorized payroll deductions to be made for the purchase of shares. The Company matched a portion of the employee contribution by contributing an additional 15% ( 25% in fiscal 2015) of the employee's payroll deduction up to a $25,000 per employee annual contribution. All shares purchased under the Old ESPP were purchased on the open market by a designated broker.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 29, 2017
Equity [Abstract]
Accumulated Other Comprehensive Income	17. Accumulated Other Comprehensive Income The components of accumulated other comprehensive income are as follows: Currency Translation Unrecognized Loss on Derivatives Unrecognized Gain (Loss) on Benefit Plans Unrecognized Gain on Equity Securities Accumulated Other Comprehensive Income Balance at September 25, 2015 $ 60.2 $ (6.4 ) $ (52.9 ) $ — $ 0.9 Other comprehensive income (loss), net 0.8 — (39.5 ) — (38.7 ) Reclassification from other comprehensive income (loss) (59.4 ) 0.5 11.1 — (47.8 ) Balance at September 30, 2016 1.6 (5.9 ) (81.3 ) — (85.6 ) Other comprehensive income (loss), net (21.1 ) — 5.3 — (15.8 ) Reclassification from other comprehensive income (loss) — 0.2 28.7 — 28.9 Balance at December 30, 2016 (19.5 ) (5.7 ) (47.3 ) — (72.5 ) Other comprehensive income (loss), net 16.0 — 5.2 1.5 22.7 Reclassification from other comprehensive income (loss) (4.7 ) 1.0 40.6 — 36.9 Balance at December 29, 2017 $ (8.2 ) $ (4.7 ) $ (1.5 ) $ 1.5 $ (12.9 ) The following summarizes reclassifications from accumulated other comprehensive income: Amount Reclassified From Accumulated Other Comprehensive Income December 29, 2017 September 30, 2016 December 30, 2016 Line Item in the Consolidated Amortization of unrealized loss on derivatives $ 1.3 $ 0.7 $ 0.2 Interest expense Income tax provision (0.3 ) (0.2 ) — Provision for income taxes Net of income taxes 1.0 0.5 0.2 Amortization of pension and post-retirement benefit plans: Net actuarial loss 2.7 11.4 1.0 (1) Prior service credit (1.9 ) (2.7 ) (0.6 ) (1) Disposal of discontinued operations (3.1 ) 0.8 — Plan settlements 70.2 8.1 45.0 (1) Total before tax 67.9 17.6 45.4 Income tax provision (27.3 ) (6.5 ) (16.7 ) Provision for income taxes Net of income taxes 40.6 11.1 28.7 Currency translation (4.7 ) (59.4 ) — Total reclassifications for the period $ 36.9 $ (47.8 ) $ 28.9 (1) These accumulated other comprehensive income components are included in the computation of net periodic benefit cost. See Note 14 for additional details.	[1]
[1]	These accumulated other comprehensive income components are included in the computation of net periodic benefit cost. See Note 14 for additional details.

Guarantees

Guarantees	12 Months Ended
	Sep. 30, 2016
Guarantees [Abstract]
Guarantees	18. Guarantees In disposing of assets or businesses, the Company has historically provided representations, warranties and indemnities to cover various risks and liabilities, including unknown damage to the assets, environmental risks involved in the sale of real estate, liability to investigate and remediate environmental contamination at waste disposal sites and manufacturing facilities, and unidentified tax liabilities related to periods prior to disposition. The Company assesses the probability of potential liabilities related to such representations, warranties and indemnities and adjusts potential liabilities as a result of changes in facts and circumstances. The Company believes, given the information currently available, that their ultimate resolution will not have a material adverse effect on its financial condition, results of operations and cash flows. In connection with the sale of the Specialty Chemical business (formerly known as Mallinckrodt Baker) in fiscal 2010, the Company agreed to indemnify the purchaser with respect to various matters, including certain environmental, health, safety, tax and other matters. The indemnification obligations relating to certain environmental, health and safety matters have a term of 17 years from the sale, while some of the other indemnification obligations have an indefinite term. The amount of the liability relating to all of these indemnification obligations included in other liabilities on the Company's consolidated balance sheets at December 29, 2017 and December 30, 2016 was $14.9 million and $15.1 million , of which $12.1 million and $12.4 million , respectively, related to environmental, health and safety matters. The value of the environmental, health and safety indemnity was measured based on the probability-weighted present value of the costs expected to be incurred to address environmental, health and safety claims made under the indemnity. The aggregate fair value of these indemnification obligations did not differ significantly from their aggregate carrying value at December 29, 2017 and December 30, 2016 . As of December 29, 2017 , the maximum future payments the Company could be required to make under these indemnification obligations was $70.2 million . The Company was required to pay $30.0 million into an escrow account as collateral to the purchaser, of which $18.3 million and $19.0 million remained in other assets on the consolidated balance sheets at December 29, 2017 and December 30, 2016 , respectively. The Company has recorded liabilities for known indemnification obligations included as part of environmental liabilities, which are discussed in Note 19. In addition, the Company is liable for product performance; however the Company believes, given the information currently available, that their ultimate resolution will not have a material adverse effect on its financial condition, results of operations and cash flows. The Company was required to provide the U.S. Nuclear Regulatory Commission financial assurance demonstrating its ability to fund the decommissioning of its Maryland Heights, Missouri radiopharmaceuticals production facility upon closure. Following the sale of the Nuclear Imaging business, the surety bond was canceled in April 2017 and the Company is no longer required to provide financial assurance to the U.S. Nuclear Regulatory Commission for that facility. As of December 29, 2017 , the Company had various other letters of credit and guarantee and surety bonds totaling $28.7 million . In addition, the separation and distribution agreement entered into with Covidien provides for cross-indemnities principally designed to place financial responsibility of the obligations and liabilities of the Company's business with the Company and financial responsibility for the obligations and liabilities of Covidien's remaining business with Covidien, among other indemnities.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 29, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	19. Commitments and Contingencies The Company has purchase obligations related to commitments to purchase certain goods and services. At December 29, 2017 , such obligations were as follows: Fiscal 2018 $ 122.6 Fiscal 2019 72.3 Fiscal 2020 60.9 Fiscal 2021 16.1 Fiscal 2022 15.4 The Company is subject to various legal proceedings and claims, including patent infringement claims, product liability matters, personal injury, environmental matters, employment disputes, contractual disputes and other commercial disputes, including those described below. The Company believes that these legal proceedings and claims likely will be resolved over an extended period of time. Although it is not feasible to predict the outcome of these matters, the Company believes, unless indicated below, given the information currently available, that their ultimate resolution will not have a material adverse effect on its financial condition, results of operations and cash flows. Governmental Proceedings Opioid Related Matters Multidistrict Litigation. The Company has been named in lawsuits court brought by various counties, cities, Native American tribes, hospitals, third-party payers and others against opioid manufacturers and, often, distributors. In general, the lawsuits assert claims of public nuisance, negligence, civil conspiracy, fraud, violations of the Racketeer Influenced and Corrupt Organizations Act or similar state laws, consumer fraud, deceptive trade practices, insurance fraud, unjust enrichment and other common law claims arising from defendants’ manufacturing, distribution, marketing and promotion of opioids and seek restitution, damages, injunctive and other relief and attorneys’ fees and costs. These lawsuits were originally filed against, or amended to include, the Company in various U.S. District Courts or in state courts with the state court lawsuits subsequently removed to U.S. District Court. On December 5, 2017 the Judicial Panel in Multidistrict Litigation (“JPML”) issued its order establishing a Multidistrict Litigation (“MDL”) in the Northern District of Ohio for opioid litigation cases and transferring those cases to the MDL that are originally filed in U.S. District Courts or removed to U.S. District Courts from state court. There are currently approximately 262 lawsuits naming the Company that are either in the MDL or are expected to be transferred to the MDL. The Company intends to vigorously defend itself in these matters. State Court Lawsuits. On December 20, 2017, the State of New Mexico, through its Attorney General, amended its lawsuit pending in the First Judicial District Court in the County of Santa Fe against certain opioid distributors and manufacturers, to add the Company. The lawsuit asserts violations of public nuisance laws and the New Mexico Unfair Practices, Medicaid Fraud and Racketeering Acts and seeks relief similar to that sought in other state and federal actions. In addition, the Company is currently named in 18 lawsuits pending in state courts in California (6), Florida (1), Louisiana (1), Maryland (1), New Jersey (1), Ohio (1), Pennsylvania (1), Tennessee (3) and West Virginia (3). These state lawsuits are brought on behalf of towns, counties, Medicaid managed care organizations, Native American tribes and an addiction recovery corporation. The lawsuits assert claims and seek damages similar to those sought in the cases pending before the MDL. The Company intends to vigorously defend itself in these state court matters. Investigations. The Company has also received various subpoenas and requests for information related to the distribution, marketing and sale of the Company’s opioid products. On July 26, 2017, the Company received a subpoena from the Department of Justice ("DOJ"), on August 24, 2017, the Company received a Civil Investigative Demand (“CID”) from the Missouri Attorney General’s Office, on September 22, 2017, the Company received a subpoena from the New Hampshire Attorney General’s Office, on January 9, 2018, the Company received a subpoena and CID from the Kentucky Attorney General’s Office, on January 16, 2018, the Company received a CID from the Attorney General’s Office for the State of Washington and on February 5, 2018, the Company received a subpoena from the Attorney General's Office from the State of Alaska. In addition, on January 27, 2018 the Company received a grand jury subpoena from the U.S. Attorneys’ Office (“USAO”) for the Southern District of Florida for documents related to the Company’s distribution, marketing and sale of its oxymorphone generic products. The Company is in the process of responding to these subpoenas and CIDs. The Company has been contacted by the coalition of State Attorneys General investigating the role manufacturers and distributors may have had in contributing to the increased use of opioids in the U.S. The Company intends to cooperate fully in these investigations. Since these lawsuits and investigations are in early stages, the Company is unable to predict its outcome or estimate a range of reasonably possible losses. Other Matters SEC Subpoena. In January 2017, the Company received a subpoena from the SEC for documents related to the Company’s public statements, filings and other disclosures regarding H.P. Acthar Gel sales, profits, revenue, promotion and pricing. The Company has responded to this subpoena, and in February 2018, the SEC notified the Company that it had concluded its investigation and that no enforcement action was recommended against the Company. Boston Subpoena. In December 2016, the Company received a subpoena from the USAO for the District of Massachusetts for documents related to the Company’s provision of financial and other support to patients, including through charitable foundations, and related matters. The Company is in the process of responding to this subpoena, and the Company intends to cooperate fully in the investigation. Texas Pricing Investigation. In November 2014, the Company received a CID from the Civil Medicaid Fraud Division of the Texas Attorney General's Office. According to the CID, the Attorney General's office is investigating the possibility of false reporting of information by the Company regarding the prices of certain of its drugs used by Texas Medicaid to establish reimbursement rates for pharmacies that dispensed the Company's drugs to Texas Medicaid recipients. The Company has responded to these requests. Mallinckrodt Inc. v. U.S. Food and Drug Administration and United States of America. In November 2014, the Company filed a Complaint ("the Complaint") in the U.S. District Court for the District of Maryland Greenbelt Division against the FDA and the United States for judicial review of what the Company believes is the FDA's inappropriate and unlawful reclassification of the Company's Methylphenidate HCl Extended-Release tablets USP (CII) ("Methylphenidate ER") in the Orange Book: Approved Drug Products with Therapeutic Equivalence ("Orange Book") on November 13, 2014. The Company also sought a temporary restraining order ("TRO") directing the FDA to reinstate the Orange Book AB rating for the Company's Methylphenidate ER products. The court denied the Company's motion for a TRO and in July 2015, the court granted the FDA’s motion to dismiss with respect to three of the five counts in the Complaint and granted summary judgment in favor of the FDA with respect to the two remaining counts. The Company appealed the court’s decision to the U.S. Court of Appeals for the Fourth Circuit. On October 18, 2016, the FDA initiated proceedings, proposing to withdraw approval of the Company's Abbreviated New Drug Application ("ANDA") for Methylphenidate ER. On October 21, 2016, the United States Court of Appeals for the Fourth Circuit issued an order placing that litigation in abeyance pending the outcome of the withdrawal proceedings. The Company concurrently submitted to the FDA requests for a hearing in the withdrawal proceeding and for an extension of the deadline for submitting documentation supporting the necessity of a hearing. The FDA granted the Company’s initial request to extend the deadline, and on February 21, 2017, the FDA suspended the deadline in order to give the Center for Drug Evaluation and Research ("CDER") an opportunity to complete its production of documents. CDER shared an initial set of documents with the Company in June 2017 and a second set of documents in October 2017. Following the Company’s receipt of the October tranche of documents from CDER, the Company presented a supplemental document request to CDER to ensure all of its initial document requests were fulfilled, and on February 13, 2018, CDER provided a final set of documents in response to the Company’s requests. The Company is preparing the legal arguments in support of its position in the withdrawal proceedings, which it will be filing in early third quarter of fiscal 2018. A potential outcome of the withdrawal proceedings is that the Company’s Methylphenidate ER products may lose their FDA approval, which could have a material, negative impact to the Company’s Specialty Generics segment. FTC Investigation. In June 2014, Questcor received a subpoena and CID from the Federal Trade Commission ("FTC") seeking documentary materials and information regarding the FTC's investigation into whether Questcor's acquisition of certain rights to develop, market, manufacture, distribute, sell and commercialize MNK-1411 (the product formerly described as Synacthen Depot®) from Novartis AG and Novartis Pharma AG (collectively, "Novartis") violates antitrust laws. Subsequently, California, Maryland, Texas, Washington, New York and Alaska (collectively, "the Investigating States") commenced similar investigations focused on whether the transaction violates state antitrust laws. On January 17, 2017, the FTC, all Investigating States (except California) ("the Settling States") and the Company entered into an agreement to resolve this matter for a one-time cash payment of $102.0 million and an agreement to license MNK-1411 to a third party designated by the FTC for possible development in Infantile Spasms ("IS") and Nephrotic Syndrome ("NS") in the U.S. To facilitate that settlement, a complaint was filed on January 18, 2017, in the U.S. District Court for the District of Columbia. The settlement was approved by the court on January 30, 2017. On July 16, 2017, the Company announced the completion of the U.S. license of both the Synacthen trademark and certain intellectual property associated with MNK-1411 to West Pharmaceuticals to develop and pursue possible FDA approval of the product in IS and NS. The Company retains the right to develop MNK-1411 for all other indications in the U.S. and retains rights to the Synacthen trademark outside the U.S. Therakos Investigation. In March 2014, the USAO for the Eastern District of Pennsylvania requested the production of documents related to an investigation of the U.S. promotion of Therakos’ drug/device system UVADEX/UVAR XTS and UVADEX/CELLEX (collectively, the "Therakos System"), for indications not approved by the FDA, including treatment of patients with graft versus host disease ("GvHD") and solid organ transplant patients, including pediatric patients. The investigation also includes Therakos’ efforts to secure FDA approval for additional uses of, and alleged quality issues relating to, UVADEX/UVAR. In August 2015, the USAO for the Eastern District of Pennsylvania sent Therakos a subsequent request for documents related to the investigation and has since made certain related requests. The Company is in the process of responding to these requests. DEA Investigation. In November 2011 and October 2012, the Company received subpoenas from the U.S. Drug Enforcement Administration ("DEA") requesting production of documents relating to its suspicious order monitoring program for controlled substances. The USAO for the Eastern District of Michigan investigated the possibility that the Company failed to report suspicious orders of controlled substances during the period 2006-2011 in violation of the Controlled Substances Act and its related regulations. The USAO for the Northern District of New York and Office of Chief Counsel for the U.S. DEA investigated the possibility that the Company failed to maintain appropriate records and security measures with respect to manufacturing of certain controlled substances at its Hobart facility during the period 2012-2013. In July 2017, the Company entered into a final settlement with the DEA and the USAOs for Eastern District of Michigan and the Northern District of New York to settle these investigations. As part of the agreement, the Company paid $35.0 million to resolve all potential claims. Questcor DOJ Investigation. In September 2012, Questcor received a subpoena from the USAO for the Eastern District of Pennsylvania for information relating to its promotional practices related to H.P. Acthar Gel. Questcor has also been informed by the USAO for the Eastern District of Pennsylvania that the USAO for the Southern District of New York and the SEC were participating in the investigation to review Questcor's promotional practices and related matters related to H.P. Acthar Gel. On March 9, 2015, the Company received a "No Action" letter from the SEC regarding its review of the Company's promotional practices related to H.P. Acthar Gel. The Company intends to cooperate fully in the investigation. Patent Litigation Inomax Patent Litigation: Praxair Distribution, Inc. and Praxair, Inc. (collectively “Praxair”). In February 2015, INO Therapeutics LLC and Ikaria, Inc., subsidiaries of the Company, filed suit in the U.S. District Court for the District of Delaware against Praxair following receipt of a January 2015 notice from Praxair concerning its submission of an ANDA containing a Paragraph IV patent certification with the FDA for a generic version of Inomax. In July 2016, the Company filed a second suit against Praxair in the U.S. District Court for the District of Delaware following receipt of a Paragraph IV notice concerning three additional patents recently added to the FDA Orange Book that was submitted by Praxair regarding its ANDA for a generic version of Inomax. The infringement claims in the second suit have been added to the original suit. In September 2016, the Company filed a third suit against Praxair in the U.S. District Court for the District of Delaware following receipt of a Paragraph IV notice concerning a fourth patent recently added to the FDA Orange Book that was submitted by Praxair regarding its ANDA for a generic version of Inomax. The Company intends to vigorously enforce its intellectual property rights relating to Inomax in both the Inter Partes Review ("IPR") and Praxair litigation proceedings to prevent the marketing of infringing generic products prior to the expiration of the patents covering Inomax. Trial of the suit filed in February 2015 was held in March 2017 and a decision was rendered September 5, 2017 that ruled five patents invalid and six patents not infringed. The Company has appealed the decision to the Court of Appeals for the Federal Circuit. An adverse outcome in the appeal of the Praxair litigation decision ultimately could result in the launch of a generic version of Inomax before the expiration of the last of the listed patents on February 19, 2034 (August 19, 2034 including pediatric exclusivity), which could adversely affect the Company's ability to successfully maximize the value of Inomax and have an adverse effect on its financial condition, results of operations and cash flows. Inomax Patents: IPR Proceedings. In February 2015 and March 2015, the U.S. Patent and Trademark Office ("USPTO") issued Notices of Filing Dates Accorded to Petitions for IPR petitions filed by Praxair Distribution, Inc. concerning ten patents covering Inomax (i.e., five patents expiring in 2029 and five patents expiring in 2031). In July 2015 the USPTO Patent Trial and Appeal Board ("PTAB") issued rulings denying the institution of four of the five IPR petitions challenging the five patents expiring in 2029. The PTAB also issued a ruling in July 2015 that instituted the IPR proceeding in the fifth of this group of patents and the PTAB ruled in July 2016 that one claim of this patent survived review and is valid while the remaining claims were unpatentable. The Company believes the valid claim describes and encompasses the manner in which Inomax is distributed in conjunction with its approved labeling and that Praxair infringes that claim. Praxair filed an appeal and Mallinckrodt filed a cross-appeal of this decision to the Court of Appeals for the Federal Circuit. Oral argument of that appeal occurred on January 9, 2017. In March 2016, Praxair Distribution, Inc. submitted additional IPR petitions for the five patents expiring in 2029. The PTAB issued non-appealable rulings in August and September 2016 denying institution of all five of these additional IPR petitions. In September 2015 the USPTO PTAB issued rulings that instituted the IPR proceedings in each of the second set of five patents that expire in 2031. In September 2016 the PTAB ruled that all claims in the five patents expiring in 2031 are patentable. Ofirmev Patent Litigation: Aurobindo Pharma U.S.A., Inc. In December 2017, Mallinckrodt Hospital Products Inc. and Mallinckrodt IP Unlimited Company, subsidiaries of the Company, and New Pharmatop LP, the current owner of the two U.S. patents licensed exclusively by the Company, filed suit in the U.S. District Court for the District of Delaware against Aurobindo Pharma U.S.A., Inc. (“Aurobindo”) alleging that Aurobindo infringed U.S. Patent No. 6,992,218 ("the ‘218 patent"), U.S. Patent No. 9,399,012 ("the ‘012 patent") and U.S. Patent No. 9,610,265 ("the ‘265 patent") following receipt of a November 2017 notice from Aurobindo concerning its submission of an ANDA, containing a Paragraph IV patent certification with the FDA for a competing version of Ofirmev. Ofirmev Patent Litigation: B. Braun Medical Inc. In April 2017, Mallinckrodt Hospital Products Inc. and Mallinckrodt IP, subsidiaries of the Company, and Pharmatop, the then owner of the two U.S. patents licensed exclusively by the Company, filed suit in the U.S. District Court for the District of Delaware against B. Braun Medical Inc. ("B. Braun") alleging that B. Braun infringed the ‘218 patent and the ‘012 patent following receipt of a February 2017 notice from B. Braun concerning its submission of a New Drug Application ("NDA"), containing a Paragraph IV patent certification with the FDA for a competing version of Ofirmev. Following receipt of a second Paragraph IV notice letter from B. Braun on April 24, 2017 directed to the ‘012 patent, Mallinckrodt Hospital Products Inc. and Mallinckrodt IP filed suit in June 2017 in the U.S. District Court for the District of Delaware against B. Braun alleging that B. Braun infringed the ‘012 patent and the ‘265 patent. In both instances, a protective suit was filed in the U.S. District Court for the Eastern District of Pennsylvania to protect the 30-month stay against any venue challenge in Delaware. In July 2017, B. Braun filed motions to dismiss both actions in Delaware due to improper venue based on the recent U.S. Supreme Court TC Heartland decision on venue in patent cases, and also filed a separate motion to dismiss in the original action in Pennsylvania. Following receipt of a third Paragraph IV notice letter from B. Braun on July 13, 2017 that included a certification to the ‘265 patent, amended complaints were filed in July 2017 in the U.S. District Courts for the Districts of Delaware and Eastern District of Pennsylvania by Mallinckrodt Hospital Products Inc., Mallinckrodt IP and Pharmatop. Also in July 2017, Mallinckrodt Hospital Products Inc., Mallinckrodt IP and Pharmatop filed a motion to stay the action in the Eastern District of Pennsylvania. A hearing occurred August 24, 2017 in the U.S. District Court for the District of Delaware regarding B. Braun’s motion to dismiss the Delaware actions for improper venue. The judge in the Delaware District Court denied B. Braun’s motion to dismiss the amended complaint without prejudice and ordered venue-related discovery on December 14, 2017. Subsequently, B. Braun withdrew the challenge to venue in Delaware but proceeded to file new motions to dismiss the Delaware actions on January 5, 2018. A scheduling conference occurred October 4, 2017 in the U.S. District Court for the Eastern District of Pennsylvania and no decisions were rendered on any of the pending motions. The actions in the U.S. District Court for the Eastern District of Pennsylvania were dismissed by stipulation on December 28, 2017. Ofirmev Patent Litigation: InnoPharma Licensing LLC and InnoPharma, Inc. In September 2014, Cadence and Mallinckrodt IP, subsidiaries of the Company, and Pharmatop, the then owner of the two U.S. patents licensed exclusively by the Company, filed suit in the U.S. District Court for the District of Delaware against InnoPharma Licensing LLC and InnoPharma, Inc. (both are subsidiaries of Pfizer and collectively "InnoPharma") alleging that InnoPharma infringed U.S. Patent Nos. 6,028,222 ("the '222 patent") and 6,992,218 ("the '218 patent") following receipt of an August 2014 notice from InnoPharma concerning its submission of a NDA, containing a Paragraph IV patent certification with the FDA for a competing version of Ofirmev. Separately, on December 1, 2016 Mallinckrodt IP Filed suit in the U.S. District Court for the District of Delaware against InnoPharma alleging that InnoPharma infringed the '012 patent. On May 4, 2017 the parties entered into settlement agreements on both suits under which InnoPharma was granted the non-exclusive right to market a competing intravenous acetaminophen product in the U.S. under its NDA on or after December 6, 2020, or earlier under certain circumstances. Ofirmev Patent Litigation: Agila Specialties Private Limited, Inc. (now Mylan Laboratories Ltd.) and Agila Specialties Inc. (a Mylan Inc. Company), (collectively “Agila”). In December 2014, Cadence and Mallinckrodt IP, subsidiaries of the Company, and Pharmatop, the then owner of the two U.S. patents licensed exclusively by the Company, filed suit in the U.S. District Court for the District of Delaware against Agila alleging that Agila infringed the '222 and the '218 patents following receipt of a November 2014 notice from Agila concerning its submission of a NDA containing a Paragraph IV patent certification with the FDA for a competing version of Ofirmev. Separately, on December 1, 2016 Mallinckrodt IP filed suit in the U.S. District Court for the District of Delaware against Agila alleging that Agila infringed the '012 patent. On December 31, 2016, the parties entered into settlement agreements on both suits under which Agila was granted the non-exclusive right to market a competing intravenous acetaminophen product in the U.S. under its NDA on or after December 6, 2020, or earlier under certain circumstances. The Company has successfully asserted the ‘222 and ‘218 patents and maintained their validity in both litigation and proceedings at the USPTO. The Company will continue to vigorously enforce its intellectual property rights relating to Ofirmev to prevent the marketing of infringing generic or competing products prior to December 6, 2020, which, if unsuccessful, could adversely affect the Company's ability to successfully maximize the value of Ofirmev and have an adverse effect on its financial condition, results of operations and cash flows. Jazz Pharmaceuticals, Inc. and Jazz Pharmaceuticals Ireland v. Mallinckrodt PLC, Mallinckrodt Inc. and Mallinckrodt LLC. In January 2018, Jazz Pharmaceuticals, Inc. and Jazz Pharmaceuticals Ireland (“Jazz”) filed suit in the U.S. District Court for the District of New Jersey against the Company alleging that the Company infringed United States Patent Nos. 7,668,730 (the “’730 patent”), 7,765,106 (the “’106 patent”), 7,765,107 (the “’107 patent”), 7,895,059 (the “’059 patent”), 8,457,988 (the “’988 patent”), 8,589,182 (the “’182 patent”), 8,731,963 (the “’963 patent”), 8,772,306 (the “’306 patent”), 9,050,302 (the “’302 patent”), and 9,486,426 (the “’426 patent”) following receipt of a November 2017 notice from the Company concerning its submission of an ANDA, containing a Paragraph IV patent certification with the FDA for a competing version of Xyrem. Tyco Healthcare Group LP, et al. v. Mutual Pharmaceutical Company, Inc. In March 2007, the Company filed a patent infringement suit in the U.S. District Court for the District of New Jersey against Mutual Pharmaceutical Co., Inc., et al. (collectively, "Mutual") after Mutual submitted an ANDA to the FDA seeking to sell a generic version of the Company's 7.5 mg RESTORIL™ sleep aid product. Mutual also filed antitrust and unfair competition counterclaims. The patents at issue have since expired or been found invalid. The trial court issued an opinion and order granting the Company's motion for summary judgment regarding Mutual's antitrust and unfair competition counterclaims. Mutual appealed this decision to the U.S. Court of Appeals for the Federal Circuit and the Federal Circuit issued a split decision, affirming the trial court in part and remanding to the trial court certain counterclaims for further proceedings. The Company filed a motion for summary judgment with the U.S. District Court regarding the remanded issues. In May 2015, the trial court issued an opinion granting-in-part and denying-in-part the Company’s motion for summary judgment. In March 2017, the parties entered into a settlement agreement and the case was dismissed. Commercial and Securities Litigation Putative Class Action Litigation (MSP) . On October 30, 2017, a putative class action lawsuit was filed against the Company and United BioSource Corporation ("UBC") in the U.S. District Court for the Central District of California. The case is captioned MSP Recovery Claims, Series II LLC, et al. v. Mallinckrodt ARD, Inc., et al. The complaint purports to be brought on behalf of two classes: all Medicare Advantage Organizations and related entities in the U.S. who purchased or provided reimbursement for H.P. Acthar Gel pursuant to (i) Medicare Part C contracts (Class 1) and (ii) Medicare Part D contracts (Class 2) since January 1, 2011, with certain exclusions. The complaint alleges that the Company engaged in anticompetitive, unfair, and deceptive acts to artificially raise and maintain the price of H.P. Acthar Gel. To this end, the complaint alleges that the Company unlawfully maintained a monopoly in a purported ACTH product market by acquiring the U.S. rights to Synacthen Depot and reaching anti-competitive agreements with the other defendants by selling H.P. Acthar Gel through an exclusive distribution network. The complaint purports to allege claims under federal and state antitrust laws and state unfair competition and unfair trade practice laws. Pursuant to a motion filed by defendants, this case has been transferred to the U.S. District Court for the Northern District of Illinois. The Company intends to vigorously defend itself in this matter. Putative Class Action Litigation . On April 6, 2017, a putative class action lawsuit was filed against the Company and UBC in the U.S. District Court for the Northern District of Illinois. The case is captioned City of Rockford v. Mallinckrodt ARD, Inc., et al. The complaint was subsequently amended, most recently on December 8, 2017, to include an additional named plaintiff and additional defendants. As amended, the complaint purports to be brought on behalf of all self-funded entities in the U.S. and its Territories, excluding any Medicare Advantage Organizations, related entities and certain others, that paid for H.P. Acthar Gel from August 2007 to the present. The lawsuit alleges that the Company engaged in anticompetitive, unfair, and deceptive acts to artificially raise and maintain the price of H.P. Acthar Gel. To this end, the suit alleges that the Company unlawfully maintained a monopoly in a purported ACTH product market by acquiring the U.S. rights to Synacthen Depot; conspired with UBC and violated anti-racketeering laws by selling H.P. Acthar Gel through an exclusive distributor; and committed a fraud on consumers by failing to correctly identify H.P. Acthar Gel’s active ingredient on package inserts. The Company intends to vigorously defend itself in this matter. Employee Stock Purchase Plan Securities Litigation. On July 20, 2017, a purported purchaser of Mallinckrodt stock through Mallinckrodt’s Employee Stock Purchase Plans (“ESPPs”), filed a derivative lawsuit in the Federal District Court in the Eastern District of Missouri, captioned Solomon v. Mallinckrodt plc, et al. , against the Company, its Chief Executive Officer Mark C. Trudeau ("CEO"), its Chief Financial Officer Matthew K. Harbaugh ("CFO"), its Controller Kathleen A. Schaefer, and current and former directors of the Company. On September 6, 2017, plaintiff voluntarily dismissed its complaint in the Federal District Court for the Eastern District of Missouri and refiled virtually the same complaint in the U.S. District Court for the District of Columbia. The complaint purports to be brought on behalf of all persons who purchased or otherwise acquired Mallinckrodt stock between November 25, 2014, and January 18, 2017, in the ESPPs. In the alternative, the plaintiff alleges a class action for those same purchasers/acquirers of stock in the ESPPs during the same period. The complaint asserts claims under Section 11 of the Securities Act, and for breach of fiduciary duty, misrepresentation, non-disclosure, mismanagement of the ESPPs’ assets and breach of contract arising from substantially similar allegations as those contained in the putative class action securities litigation described in the following paragraph. The Company intends to vigorously defend itself in this matter. Putative Class Action Securities Litigation. On January 23, 2017, a putative class action lawsuit was filed against the Company and its CEO in the U.S. District Court for the District of Columbia, captioned Patricia A. Shenk v. Mallinckrodt plc, et al . The complaint purports to be brought on behalf of all persons who purchased Mallinckrodt’s publicly traded securities on a domestic exchange between November 25, 2014 and January 18, 2017. The lawsuit generally alleges that the Company made false or misleading statements related to H.P. Acthar Gel and Synacthen to artificially inflate the price of the Company’s stock. In particular, the complaint alleges a failure by the Company to provide accurate disclosures concerning the long-term sustainability of H.P. Acthar Gel revenues, and the exposure of H.P. Acthar Gel to Medicare and Medicaid reimbursement rates. On January 26, 2017, a second putative class action lawsuit, captioned Jyotindra Patel v. Mallinckrodt plc, et al. was filed against the same defendants named in the Shenk lawsuit in the U.S. District Court for the District of Columbia. The Patel complaint purports to be brought on behalf of shareholders during the same period of time as that set forth in the Shenk lawsuit and asserts claims similar to those set forth in the Shenk lawsuit. On March 13, 2017, a third putative class action lawsuit, captioned Amy T. Schwartz, et al., v. Mallinckrodt plc, et al., was filed against the same defendants named in the Shenk lawsuit in the U.S. District Court for the District of Columbia. The Schwartz complaint purports to be brought on behalf of shareholders who purchased shares of the Company between July 14, 2014 and January 18, 2017 and asserts claims similar to those set forth in the Shenk lawsuit. On March 23, 2017, a fourth putative class action lawsuit, captioned Fulton County Employees’ Retirement System v. Mallinckrodt plc, et al., was filed against the Company and its CEO and CFO in the U.S. District Court for the District of Columbia. The Fulton County complaint purports to be brought on behalf of shareholders during the same period of time as that set forth in the Schwartz lawsuit and asserts claims similar to those set forth in the Shenk lawsuit. On March 27, 2017, four separate plaintiff groups moved to consolidate the pending cases and to be appointed as lead plaintiffs in the consolidated case. Since that time, two of the plaintiff groups have withdrawn their motions. The Company intends to vigorously defend itself in this matter. Retrophin Litigation. In January 2014, Retrophin, Inc. ("R

Financial Instruments and Fair

Financial Instruments and Fair Value Measurements	12 Months Ended
	Dec. 29, 2017
Fair Value Disclosures [Abstract]
Financial Instruments and Fair Value Measurements	20. Financial Instruments and Fair Value Measurements Fair value is defined as the exit price that would be received from the sale of an asset or paid to transfer a liability, using assumptions that market participants would use in pricing an asset or liability. The fair value guidance establishes a three-level fair value hierarchy, which maximizes the use of observable inputs and minimizes the use of unobservable inputs used in measuring fair value. The levels within the hierarchy are as follows: Level 1— observable inputs such as quoted prices in active markets for identical assets or liabilities; Level 2— significant other observable inputs that are observable either directly or indirectly; and Level 3— significant unobservable inputs in which there is little or no market data, which requires the Company to develop its own assumptions. The following tables provide a summary of the significant assets and liabilities that are measured at fair value on a recurring basis at the end of each period: December 29, Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Assets: Debt and equity securities held in rabbi trusts $ 35.4 $ 24.0 $ 11.4 $ — Equity securities 22.7 22.7 — — Foreign exchange forward and option contracts 0.1 0.1 — — $ 58.2 $ 46.8 $ 11.4 $ — Liabilities: Deferred compensation liabilities $ 42.7 $ — $ 42.7 $ — Contingent consideration and acquired contingent liabilities 246.4 — — 246.4 Foreign exchange forward and option contracts 0.1 0.1 — — $ 289.2 $ 0.1 $ 42.7 $ 246.4 December 30, Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Debt and equity securities held in rabbi trusts $ 33.6 $ 22.8 $ 10.8 $ — Foreign exchange forward and option contracts 0.7 0.7 — — $ 34.3 $ 23.5 $ 10.8 $ — Liabilities: Deferred compensation liabilities $ 32.5 $ — $ 32.5 $ — Contingent consideration and acquired contingent liabilities 250.5 — — 250.5 Foreign exchange forward and option contracts 3.4 3.4 — — $ 286.4 $ 3.4 $ 32.5 $ 250.5 Debt and equity securities held in rabbi trust. Debt securities held in the rabbi trust primarily consist of U.S. government and agency securities and corporate bonds. When quoted prices are available in an active market, the investments are classified as level 1. When quoted market prices for a security are not available in an active market, they are classified as level 2. Equity securities held in the rabbi trust primarily consist of U.S. common stocks, which are valued using quoted market prices reported on nationally recognized securities exchanges. Equity securities . Equity securities consist of shares in Mesoblast Ltd., for which quoted prices are available in an active market; therefore, the investment is classified as level 1 and is valued based on quoted market prices reported on a nationally recognized securities exchange. Foreign exchange forward and option contracts. Foreign currency option and forward contracts are used to economically manage the foreign exchange exposures of operations outside the U.S. Quoted prices are available in an active market; as such, these derivatives are classified as level 1. Deferred compensation liabilities. The Company maintains a non-qualified deferred compensation plan in the U.S., which permits eligible employees of the Company to defer a portion of their compensation. A recordkeeping account is set up for each participant and the participant chooses from a variety of funds for the deemed investment of their accounts. The recordkeeping accounts generally correspond to the funds offered in the Company's U.S. tax-qualified defined contribution retirement plan and the account balance fluctuates with the investment returns on those funds. Goodwill. The Company performs an annual goodwill impairment assessment using an income approach based on the present value of future cash flows. See further discussion in Notes 3 and 12 to the consolidated financial statements. Contingent consideration and acquired contingent liabilities. In August 2014, the Company recorded acquired contingent liabilities of $195.4 million from the Questcor Acquisition. The contingent liabilities relate to Questcor's contingent obligations associated with their acquisition of an exclusive, perpetual and irrevocable license to develop, market, manufacture, distribute, sell and commercialize Synacthen and MNK-1411 (collectively "Synacthen") from Novartis AG and Novartis Pharma AG (collectively "Novartis") and their acquisition of BioVectra. The fair value of these contingent consideration obligations at December 29, 2017 and December 30, 2016 were $111.8 million and $124.7 million , respectively. Under the terms of the license agreement with Novartis, the Company made a $25.0 million payment in fiscal 2017, and is obligated to make annual payments of $25.0 million subsequent to fiscal 2017 until such time that the Company obtains FDA approval of Synacthen and makes a $25.0 million payment upon obtaining FDA approval of Synacthen. If FDA approval is obtained, the Company will pay an annual royalty to Novartis based on a percentage of net sales in the U.S. market. As of December 29, 2017, the total remaining payments under the license agreement shall not exceed $140.0 million . The terms of the license agreement allow the Company to terminate the license agreement upon the occurrence of certain events following the fiscal 2020 payment. The Company measured the fair value of the contingent payments based on a probability-weighted present value of the consideration expected to be transferred using a discount rate of 4.7% . Based on the terms of the acquisition agreement with the former shareholders of BioVectra, the Company was obligated to pay additional cash consideration of $50.0 million CAD based on BioVectra's financial results from January 2013 through a portion of fiscal 2016. During fiscal 2015, the Company made a $5.0 million CAD payment. During fiscal 2016, the Company paid the remaining obligation of $40.0 million CAD to the former owners of BioVectra to reach the maximum cumulative payment of $50.0 million CAD. At December 29, 2017, there are no further contingent liabilities associated with BioVectra. As part of the Hemostasis Acquisition, the Company provided contingent consideration to The Medicines Company in the form of sales based milestones associated with Raplixa and PreveLeak, and acquired contingent liabilities associated with The Medicines Company's prior acquisitions of the aforementioned products. The Company determined the fair value of the contingent consideration and acquired contingent liabilities based on an option pricing model to be $7.0 million and $17.1 million , respectively, at December 29, 2017 compared to $58.9 million and $11.2 million , respectively, at December 30, 2016. As of December 29, 2017, the contingent consideration liability associated with Raplixa was reduced to zero, reflective of lower than previously anticipated commercial opportunities for the product, resulting in a $54.6 million fair value adjustment during fiscal 2017. As part of the Stratatech Acquisition, the Company provided contingent consideration to the prior shareholders of Stratatech, primarily in the form of regulatory filing and approval milestones associated with the deep partial thickness and full thickness indications associated with the StrataGraft product. The Company assesses the likelihood of and timing of making such payments. The Company determined the fair value of the contingent consideration associated with the Stratatech Acquisition to be $53.5 million and $55.7 million at December 29, 2017 and December 30, 2016, respectively. As part of the InfaCare Acquisition, the Company provided contingent consideration to the prior shareholders of InfaCare in the form of both regulatory approval milestones for full-term and pre-term neonates for stannsoporfin and sales-based milestones associated with stannsoporfin. The Company determined the fair value of the contingent consideration based on an option pricing model to be $35.0 million as of December 29, 2017. As part of the Ocera Acquisition, the Company provided contingent consideration to the prior shareholders of Ocera in the form of both patient enrollment clinical study milestones for IV and Oral formulations of MNK-6105 and sales-based milestones associated with MNK-6105. The Company determined the fair value of the contingent consideration based on an option pricing model to be $22.0 million as of December 11, 2017. Of the total fair value of the contingent consideration of $246.4 million , $64.0 million was classified as current and $182.4 million was classified as non-current in the consolidated balance sheets as of December 29, 2017. The following table summarizes the fiscal 2017 activity for contingent considerations: Balance at December 30, 2016 $ 250.5 Acquisition date fair value of contingent consideration 57.0 Payments (25.0 ) Accretion expense 5.3 Fair value adjustment (41.4 ) Balance at December 29, 2017 $ 246.4 Financial Instruments Not Measured at Fair Value The following methods and assumptions were used by the Company in estimating fair values for financial instruments not measured at fair value as of December 29, 2017 and December 30, 2016 : • The carrying amounts of cash and cash equivalents, accounts receivable, accounts payable and the majority of other current assets and liabilities approximate fair value because of their short-term nature. The Company classifies cash on hand and deposits in banks, including commercial paper, money market accounts and other investments it may hold from time to time, with an original maturity to the Company of three months or less, as cash and cash equivalents (level 1). The fair value of restricted cash is equivalent to its carrying value of $18.3 million and $19.1 million as of December 29, 2017 and December 30, 2016 , respectively (level 1), substantially all of which is included in other assets on the consolidated balance sheets. • The Company received a portion of consideration for the sale of the Intrathecal business in the form of a note receivable. The fair value of the note receivable was equivalent to its carrying value of $154.0 million as of December 29, 2017 (level 1). • The Company entered into short-term investment certificates during the three months ended December 30, 2016. These certificates are carried at cost, which approximates fair value, of zero and $11.1 million at December 29, 2017 and December 30, 2016 , respectively (level 2). These certificates are included in prepaid expenses and other current assets on the consolidated balance sheets. • The Company's life insurance contracts are carried at cash surrender value, which is based on the present value of future cash flows under the terms of the contracts (level 3). Significant assumptions used in determining the cash surrender value include the amount and timing of future cash flows, interest rates and mortality charges. The fair value of these contracts approximates the carrying value of $67.0 million and $67.6 million at December 29, 2017 and December 30, 2016 , respectively. These contracts are included in other assets on the consolidated balances sheets. • The carrying values of the Company's revolving credit facility and variable rate receivable securitization approximate the fair values due to the short-term nature of these instruments, and is therefore classified as level 1. The carrying value of the 4.00% term loan approximates the fair value of this instrument, as calculated using the discounted exit price for the instrument, and is therefore classified as level 3. Since the quoted market prices for the Company's term loans and 8.00% and 9.50% debentures are not available in an active market, they are classified as level 2 for purposes of developing an estimate of fair value. The Company's 3.50% , 4.75% , 4.875% , 5.50% , 5.625% and 5.75% notes are classified as level 1, as quoted prices are available in an active market for these notes. The following table presents the carrying values and estimated fair values of the Company's long-term debt, excluding capital leases, as of the end of each period: December 29, 2017 December 30, 2016 Carrying Value Fair Value Carrying Value Fair Value Level 1: Variable-rate receivable securitization due July 2017 $ — $ — $ 250.0 $ 250.0 3.50% notes due April 2018 300.0 299.1 300.0 298.7 4.875% notes due April 2020 700.0 675.2 700.0 699.5 Variable-rate receivable securitization due July 2020 200.0 200.0 — — 5.75% notes due August 2022 884.0 804.8 884.0 850.3 4.75% notes due April 2023 526.5 412.4 600.0 520.9 5.625% notes due October 2023 738.0 628.8 738.0 682.4 5.50% notes due April 2025 692.1 564.5 695.0 615.7 Revolving credit facility 900.0 900.0 100.0 100.0 Level 2: Term loans due March 2021 — — 1,948.5 1,953.2 9.50% debentures due May 2022 10.4 10.9 10.4 12.0 8.00% debentures due March 2023 4.4 4.4 4.4 4.9 Term loan due September 2024 1,851.2 1,848.7 — — Level 3: 4.00% term loan due February 2022 — — 6.5 6.5 Concentration of Credit and Other Risks Financial instruments that potentially subject the Company to concentrations of credit risk primarily consist of accounts receivable. The Company generally does not require collateral from customers. A portion of the Company's accounts receivable outside the U.S. includes sales to government-owned or supported healthcare systems in several countries, which are subject to payment delays. Payment is dependent upon the financial stability and creditworthiness of those countries' national economies. The following table shows net sales attributable to distributors that accounted for 10% or more of the Company's total net sales: Fiscal Year Ended Three Months Ended December 29, September 30, September 25, December 30, CuraScript, Inc. 40 % 38 % 35 % 43 % McKesson Corporation * 12 % 20 % 10 % AmerisourceBergen Corporation * * 10 % * Cardinal Health, Inc. * * 11 % * * Net sales to these distributors were less than 10% of total net sales during the respective periods presented above. The following table shows accounts receivable attributable to distributors that accounted for 10% or more of the Company's gross accounts receivable at the end of each period: December 29, December 30, McKesson Corporation 26 % 28 % AmerisourceBergen Corporation 15 % 15 % CuraScript, Inc. 14 % 15 % Cardinal Health, Inc. 11 % 10 % The following table shows net sales attributable to products that accounted for 10% or more of the Company's total net sales: Fiscal Year Ended Three Months Ended December 29, September 30, September 25, December 30, H.P. Acthar Gel 37 % 34 % 35 % 39 % Inomax 16 % 14 % 6 % 14 %

Segment and Geographical Data

Segment and Geographical Data	12 Months Ended
	Dec. 29, 2017
Segment Reporting [Abstract]
Segment and Geographical Data	21. Segment and Geographical Data Through December 29, 2017, the Company operated its business under two reportable segments, which are described below: • Specialty Brands includes branded medicines; and • Specialty Generics includes specialty generic drugs, API and external manufacturing. Management measures and evaluates the Company's operating segments based on segment net sales and operating income. Management excludes corporate expenses from segment operating income. In addition, certain amounts that management considers to be non-recurring or non-operational are excluded from segment operating income because management evaluates the operating results of the segments excluding such items. These items include, but are not limited to, revenues and expenses associated with sales of products to the acquirer of the CMDS business under an ongoing supply agreement, intangible asset amortization, net restructuring and related charges, non-restructuring impairments and separation costs. Although these amounts are excluded from segment operating income, as applicable, they are included in reported consolidated operating income and in the following reconciliations presented below. Management manages assets on a total company basis, not by operating segment. The chief operating decision maker does not regularly review any asset information by operating segment and, accordingly, the Company does not report asset information by operating segment. Total assets were approximately $15.3 billion and $15.2 billion at December 29, 2017 and December 30, 2016 , respectively. As a result of the sales of the CMDS and Nuclear Imaging businesses to Guerbet and IBAM, respectively, the financial results of these businesses are presented as discontinued operations. Therefore, prior year amounts have been recast to conform to current presentation. Selected information by business segment is as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Net sales: Specialty Brands $ 2,325.3 $ 2,300.6 $ 1,622.8 $ 603.1 Specialty Generics 839.5 1,025.2 1,251.6 212.9 Net sales of operating segments (1) 3,164.8 3,325.8 2,874.4 816.0 Other (2) 56.8 55.0 48.7 13.9 Net sales $ 3,221.6 $ 3,380.8 $ 2,923.1 $ 829.9 Operating income: Specialty Brands $ 1,155.2 $ 1,166.2 $ 637.6 $ 317.2 Specialty Generics 231.5 376.1 594.4 52.7 Segment operating income 1,386.7 1,542.3 1,232.0 369.9 Unallocated amounts: Corporate and allocated expenses (3) (172.0 ) (169.8 ) (282.6 ) (181.4 ) Intangible asset amortization (694.5 ) (700.1 ) (550.3 ) (175.7 ) Restructuring and related charges, net (4) (36.4 ) (38.2 ) (45.3 ) (5.3 ) Non-restructuring impairments (63.7 ) (16.9 ) — (214.3 ) Operating income $ 420.1 $ 617.3 $ 353.8 $ (206.8 ) Depreciation and amortization (5) : Specialty Brands $ 708.2 $ 716.6 $ 559.5 $ 178.4 Specialty Generics 100.1 96.8 81.6 24.8 $ 808.3 $ 813.4 $ 641.1 $ 203.2 (1) Amounts represent sales to external customers. There were no intersegment sales. (2) Represents net sales from an ongoing, post-divestiture supply agreement with the acquirer of the CMDS business. Amounts for periods prior to the divestiture represent the reclassification of intercompany sales to third-party sales to conform with the expected presentation of the ongoing supply agreement. (3) Includes administration expenses and certain compensation, environmental and other costs not charged to the Company's operating segments. (4) Includes restructuring-related accelerated depreciation. (5) Depreciation for certain shared facilities is allocated based on occupancy percentage. Net sales by product family within the Company's segments are as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 H.P. Acthar Gel $ 1,195.1 $ 1,160.4 $ 1,037.3 $ 325.4 Inomax 505.2 474.3 185.2 118.3 Ofirmev 302.5 284.3 263.0 72.5 Therakos 214.9 207.6 — 47.4 Hemostasis products 55.1 42.5 — 13.4 Other 52.5 131.5 137.3 26.1 Specialty Brands 2,325.3 2,300.6 1,622.8 603.1 Hydrocodone (API) and hydrocodone-containing tablets 85.3 146.5 167.2 23.2 Oxycodone (API) and oxycodone-containing tablets 78.8 126.2 154.6 24.3 Methylphenidate ER 71.7 103.5 136.5 22.0 Other controlled substances 409.6 468.1 572.2 104.9 Other 194.1 180.9 221.1 38.5 Specialty Generics 839.5 1,025.2 1,251.6 212.9 Other (1) 56.8 55.0 48.7 13.9 Net sales $ 3,221.6 $ 3,380.8 $ 2,923.1 $ 829.9 (1) Represents net sales from an ongoing, post-divestiture supply agreement with the acquirer of the CMDS business. Amounts for periods prior to the divestiture represent the reclassification of intercompany sales to third-party sales to conform with the expected presentation of the ongoing supply agreement. Selected information by geographic area excluding assets held for sale is as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Net sales (1) : U.S. $ 2,899.0 $ 3,095.4 $ 2,647.0 $ 763.7 Europe, Middle East and Africa 242.3 211.8 159.0 52.8 Other 80.3 73.6 117.1 13.4 $ 3,221.6 $ 3,380.8 $ 2,923.1 $ 829.9 Fiscal Year Ended Long-lived assets (2) : December 29, 2017 December 30, 2016 U.S. $ 788.5 $ 759.1 Europe, Middle East and Africa (3) 127.0 82.9 Other 63.5 51.5 $ 979.0 $ 893.5 (1) Net sales are attributed to regions based on the location of the entity that records the transaction, none of which relate to the country of Ireland. (2) Long-lived assets are primarily composed of property, plant and equipment, net. (3) Includes long-lived assets located in Ireland of $126.0 million and $80.9 million as of December 29, 2017 and December 30, 2016, respectively.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 29, 2017
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	22. Selected Quarterly Financial Data (Unaudited) A summary of quarterly financial information for fiscal 2017 and fiscal 2016 is as follows: For the Quarter Ended March 31, 2017 June 30, 2017 September 29, 2017 December 29, 2017 Net sales $ 810.9 $ 824.5 $ 793.9 $ 792.3 Gross profit 418.6 416.1 400.6 421.0 Income from continuing operations (2) 28.9 70.6 64.3 1,607.4 Income from discontinued operations 370.3 (7.8 ) (0.6 ) 1.3 Net income 399.2 62.8 63.7 1,608.7 Basic earnings per share from continuing operations (1) $ 0.28 $ 0.72 $ 0.66 $ 17.43 Diluted earnings per share from continuing operations (1) 0.28 0.72 0.66 17.40 For the Quarter Ended December 25, 2015 March 25, 2016 June 24, 2016 September 30, 2016 Net sales $ 811.2 $ 815.8 $ 866.6 $ 887.2 Gross profit 450.9 425.1 488.8 490.2 Income from continuing operations 103.8 98.5 176.7 110.0 Income from discontinued operations 107.3 19.8 22.6 5.0 Net income 211.1 118.3 199.3 115.0 Basic earnings per share from continuing operations (1) $ 0.90 $ 0.89 $ 1.63 $ 1.02 Diluted earnings per share from continuing operations (1) 0.89 0.88 1.62 1.01 (1) Quarterly and annual computations are prepared independently. Therefore, the sum of each quarter may not necessarily total the fiscal period amounts noted elsewhere within this Annual Report on Form 10-K. (2) Income from continuing operations for the quarter ended December 29, 2017 reflects one-time effects for the completion of the Reorganization and the impact of U.S. Tax Reform.

Condensed Consolidating and Com

Condensed Consolidating and Combining Financial Statements	12 Months Ended
	Dec. 29, 2017
Condensed Consolidating Financial Statements [Abstract]
Condensed Consolidating and Combining Financial Statements	23. Condensed Consolidating Financial Statements MIFSA is a holding company established to own, directly or indirectly, substantially all of the operating subsidiaries of the Company, to issue debt securities and to perform treasury operations. MIFSA is the borrower under the Notes, which are fully and unconditionally guaranteed by Mallinckrodt plc. The following information provides the composition of the Company's comprehensive income, assets, liabilities, equity and cash flows by relevant group within the Company: Mallinckrodt plc as guarantor of the Notes, MIFSA as issuer of the Notes and the operating companies that represent assets of MIFSA. There are no subsidiary guarantees related to the Notes. Set forth below are the condensed consolidating balance sheets as of December 29, 2017 and December 30, 2016 and condensed consolidating statements of comprehensive income and cash flows for the fiscal three years ended December 29, 2017 and the three months ended December 30, 2016. Eliminations represent adjustments to eliminate investments in subsidiaries and intercompany balances and transactions between or among Mallinckrodt plc, MIFSA and the other subsidiaries. Condensed consolidating financial information for Mallinckrodt plc and MIFSA, on a standalone basis, has been presented using the equity method of accounting for subsidiaries. MALLINCKRODT PLC CONDENSED CONSOLIDATING BALANCE SHEET As of December 29, 2017 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Assets Current Assets: Cash and cash equivalents $ 0.7 $ 908.8 $ 351.4 $ — $ 1,260.9 Accounts receivable, net — — 445.8 — 445.8 Inventories — — 340.4 — 340.4 Deferred income taxes — — — — — Prepaid expenses and other current assets 1.0 0.2 82.9 — 84.1 Notes receivable — — 154.0 — 154.0 Current assets held for sale — — — — Intercompany receivable 70.0 173.4 831.4 (1,074.8 ) — Total current assets 71.7 1,082.4 2,205.9 (1,074.8 ) 2,285.2 Property, plant and equipment, net — — 966.8 — 966.8 Goodwill — — 3,482.7 — 3,482.7 Intangible assets, net — — 8,375.0 — 8,375.0 Long-term assets held for sale — — — — — Investment in subsidiaries 6,551.6 23,217.8 12,356.2 (42,125.6 ) — Intercompany loan receivable 593.1 — 4,664.8 (5,257.9 ) — Other assets — — 171.2 — 171.2 Total Assets $ 7,216.4 $ 24,300.2 $ 32,222.6 $ (48,458.3 ) $ 15,280.9 — Liabilities and Shareholders' Equity Current Liabilities: Current maturities of long-term debt $ — $ 313.5 $ 0.2 $ — $ 313.7 Accounts payable 0.1 — 113.2 — 113.3 Accrued payroll and payroll-related costs — — 98.5 — 98.5 Accrued interest — 53.0 4.0 — 57.0 Income taxes payable — — 15.8 — 15.8 Accrued and other current liabilities 0.8 0.4 450.9 — 452.1 Current liabilities held for sale — — — — — Intercompany payable 693.5 104.6 276.7 (1,074.8 ) — Total current liabilities 694.4 471.5 959.3 (1,074.8 ) 1,050.4 Long-term debt — 6,206.8 214.1 — 6,420.9 Pension and postretirement benefits — — 67.1 — 67.1 Environmental liabilities — — 73.2 — 73.2 Deferred income taxes — — 689.0 — 689.0 Other income tax liabilities — — 94.1 — 94.1 Long-term liabilities held for sale — — — — — Intercompany loans payable — 5,257.9 — (5,257.9 ) — Other liabilities — 7.8 356.4 — 364.2 Total liabilities 694.4 11,944.0 2,453.2 (6,332.7 ) 8,758.9 Shareholders' equity 6,522.0 12,356.2 29,769.4 (42,125.6 ) 6,522.0 Total Liabilities and Shareholders' Equity $ 7,216.4 $ 24,300.2 $ 32,222.6 $ (48,458.3 ) $ 15,280.9 MALLINCKRODT PLC CONDENSED CONSOLIDATING BALANCE SHEET As of December 30, 2016 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Assets Current Assets: Cash and cash equivalents $ 0.5 $ 44.5 $ 297.0 $ — $ 342.0 Accounts receivable, net — — 431.0 — 431.0 Inventories — — 350.7 — 350.7 Deferred income taxes — — — — — Prepaid expenses and other current assets 1.0 — 130.9 — 131.9 Notes receivable — — — — — Current assets held for sale — — 310.9 — 310.9 Intercompany receivable 59.7 65.1 1,081.3 (1,206.1 ) — Total current assets 61.2 109.6 2,601.8 (1,206.1 ) 1,566.5 Property, plant and equipment, net — — 881.5 — 881.5 Goodwill — — 3,498.1 — 3,498.1 Intangible assets, net — — 9,000.5 — 9,000.5 Long-term assets held for sale — — — — — Investment in subsidiaries 5,534.1 20,624.1 10,988.5 (37,146.7 ) — Intercompany loan receivable 3.5 — 3,325.9 (3,329.4 ) — Other assets — — 259.7 — 259.7 Total Assets $ 5,598.8 $ 20,733.7 $ 30,556.0 $ (41,682.2 ) $ 15,206.3 Liabilities and Shareholders' Equity Current Liabilities: Current maturities of long-term debt $ — $ 19.7 $ 251.5 $ — $ 271.2 Accounts payable 0.1 0.1 111.9 — 112.1 Accrued payroll and payroll-related costs — — 76.1 — 76.1 Accrued interest — 53.9 14.8 — 68.7 Income taxes payable — — 101.7 — 101.7 Accrued and other current liabilities 1.9 7.5 547.7 — 557.1 Current liabilities held for sale — — 120.3 — 120.3 Intercompany payable 612.5 467.1 126.5 (1,206.1 ) — Total current liabilities 614.5 548.3 1,350.5 (1,206.1 ) 1,307.2 Long-term debt — 5,860.6 20.2 — 5,880.8 Pension and postretirement benefits — — 136.4 — 136.4 Environmental liabilities — — 73.0 — 73.0 Deferred income taxes — — 2,398.1 — 2,398.1 Other income tax liabilities — — 70.4 — 70.4 Long-term liabilities held for sale — — — — — Intercompany loans payable — 3,329.4 — (3,329.4 ) — Other liabilities — 7.0 349.1 — 356.1 Total liabilities 614.5 9,745.3 4,397.7 (4,535.5 ) 10,222.0 Shareholders' equity 4,984.3 10,988.4 26,158.3 (37,146.7 ) 4,984.3 Total Liabilities and Shareholders' Equity $ 5,598.8 $ 20,733.7 $ 30,556.0 $ (41,682.2 ) $ 15,206.3 MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME Fiscal year ended December 29, 2017 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Net sales $ — $ — $ 3,221.6 $ — $ 3,221.6 Cost of sales 2.6 — 1,562.7 — 1,565.3 Gross profit (2.6 ) — 1,658.9 — 1,656.3 Selling, general and administrative expenses 59.5 0.7 860.7 — 920.9 Research and development expenses 5.1 — 272.2 — 277.3 Restructuring charges, net — — 31.2 — 31.2 Non-restructuring impairment charges — — 63.7 — 63.7 Separation costs — — — — — Gains on divestiture and license — — (56.9 ) — (56.9 ) Operating income (loss) (67.2 ) (0.7 ) 488.0 — 420.1 Interest expense (13.8 ) (353.9 ) (74.2 ) 72.8 (369.1 ) Interest income 7.3 1.2 68.9 (72.8 ) 4.6 Other income (expense), net 20.3 (1.7 ) (12.6 ) — 6.0 Intercompany interest and fees (18.3 ) — 18.3 — — Equity in net income of subsidiaries 2,200.0 2,901.8 2,549.9 (7,651.7 ) — Income from continuing operations before income taxes 2,128.3 2,546.7 3,038.3 (7,651.7 ) 61.6 Benefit from income taxes (6.1 ) (5.3 ) (1,698.2 ) — (1,709.6 ) Income from continuing operations 2,134.4 2,552.0 4,736.5 (7,651.7 ) 1,771.2 (Loss) income from discontinued operations, net of income taxes — (2.1 ) 365.3 — 363.2 Net income 2,134.4 2,549.9 5,101.8 (7,651.7 ) 2,134.4 Other comprehensive income, net of tax 59.6 59.6 118.2 (177.8 ) 59.6 Comprehensive income $ 2,194.0 $ 2,609.5 $ 5,220.0 $ (7,829.5 ) $ 2,194.0 MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME Fiscal year ended September 30, 2016 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Net sales $ — $ — $ 3,380.8 $ — $ 3,380.8 Cost of sales — — 1,525.8 — 1,525.8 Gross profit — — 1,855.0 — 1,855.0 Selling, general and administrative expenses 51.3 0.8 873.2 — 925.3 Research and development expenses — — 262.2 — 262.2 Restructuring charges, net — — 33.3 — 33.3 Non-restructuring impairments — — 16.9 — 16.9 Separation costs — — — — — Gains on divestiture and license — — — — — Operating (loss) income (51.3 ) (0.8 ) 669.4 — 617.3 — Interest expense (230.3 ) (327.0 ) (82.4 ) 255.1 (384.6 ) Interest income — 0.5 255.9 (255.1 ) 1.3 Other income (expense), net 90.0 1.7 (92.3 ) — (0.6 ) Intercompany interest and fees (16.1 ) — 16.1 — — Equity in net income of subsidiaries 820.8 1,327.2 1,057.9 (3,205.9 ) — Income from continuing operations before income taxes 613.1 1,001.6 1,824.6 (3,205.9 ) 233.4 Benefit from income taxes (30.6 ) (18.1 ) (206.9 ) — (255.6 ) Income from continuing operations 643.7 1,019.7 2,031.5 (3,205.9 ) 489.0 Income from discontinued operations, net of income taxes — 38.2 116.5 — 154.7 Net income 643.7 1,057.9 2,148.0 (3,205.9 ) 643.7 Other comprehensive loss, net of tax (86.5 ) (86.5 ) (173.5 ) 260.0 (86.5 ) Comprehensive income $ 557.2 $ 971.4 $ 1,974.5 $ (2,945.9 ) $ 557.2 MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME Fiscal year ended September 25, 2015 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Net sales $ — $ — $ 2,923.1 $ — $ 2,923.1 Cost of sales — — 1,300.2 — 1,300.2 Gross profit — — 1,622.9 — 1,622.9 Selling, general and administrative expenses 116.3 15.7 891.8 — 1,023.8 Research and development expenses — — 203.3 — 203.3 Restructuring charges, net 9.8 — 35.2 — 45.0 Non-restructuring impairments — — — — — Separation costs — — — — — Gains on divestiture and license — — (3.0 ) — (3.0 ) Operating (loss) income (126.1 ) (15.7 ) 495.6 — 353.8 Interest expense (96.4 ) (230.2 ) (25.2 ) 96.2 (255.6 ) Interest income — 0.1 97.1 (96.2 ) 1.0 Other income (expense), net 216.3 — (208.2 ) — 8.1 Intercompany interest and fees (14.7 ) — 14.7 — — Equity in net income of subsidiaries 330.6 496.3 250.5 (1,077.4 ) — Income from continuing operations before income taxes 309.7 250.5 624.5 (1,077.4 ) 107.3 Benefit from income taxes (15.9 ) — (113.4 ) — (129.3 ) Income from continuing operations 325.6 250.5 737.9 (1,077.4 ) 236.6 (Loss) income from discontinued operations, net of income taxes (0.9 ) — 89.0 — 88.1 Net income 324.7 250.5 826.9 (1,077.4 ) 324.7 Other comprehensive loss, net of tax (64.8 ) (64.8 ) (69.9 ) 134.7 (64.8 ) Comprehensive income $ 259.9 $ 185.7 $ 757.0 $ (942.7 ) $ 259.9 MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME Three months ended December 30, 2016 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Net sales $ — $ — $ 829.9 $ — $ 829.9 Cost of sales — — 384.1 — 384.1 Gross profit — — 445.8 — 445.8 Selling, general and administrative expenses 13.4 0.2 354.7 — 368.3 Research and development expenses — — 66.2 — 66.2 Restructuring charges, net — — 3.8 — 3.8 Non-restructuring impairments — — 214.3 — 214.3 Separation costs — — — — — Gains on divestiture and license — — — — — Operating loss (13.4 ) (0.2 ) (193.2 ) — (206.8 ) Interest expense (2.9 ) (81.1 ) (17.9 ) 10.6 (91.3 ) Interest income — 0.1 11.0 (10.6 ) 0.5 Other income (expense), net 1.8 0.7 (3.4 ) — (0.9 ) Intercompany interest and fees (4.4 ) — 4.4 — — Equity in net income of subsidiaries (136.5 ) 35.2 (44.5 ) 145.8 — Loss from continuing operations before income taxes (155.4 ) (45.3 ) (243.6 ) 145.8 (298.5 ) Benefit from income taxes (2.2 ) (0.3 ) (119.2 ) — (121.7 ) Loss from continuing operations (153.2 ) (45.0 ) (124.4 ) 145.8 (176.8 ) Income from discontinued operations, net of income taxes — 0.4 23.2 — 23.6 Net loss (153.2 ) (44.6 ) (101.2 ) 145.8 (153.2 ) Other comprehensive income, net of tax 13.1 13.1 26.0 (39.1 ) 13.1 Comprehensive loss $ (140.1 ) $ (31.5 ) $ (75.2 ) $ 106.7 $ (140.1 ) MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS Fiscal year ended December 29, 2017 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Cash Flows From Operating Activities: Net cash from operating activities $ 1,233.2 $ 1,139.4 $ 2,274.9 $ (3,920.2 ) $ 727.3 Cash Flows From Investing Activities: Capital expenditures — — (186.1 ) — (186.1 ) Acquisitions and intangibles, net of cash acquired — — (76.3 ) — (76.3 ) Proceeds from disposal of discontinued operations, net of cash — — 576.9 — 576.9 Intercompany loan investment (589.5 ) — (1,157.9 ) 1,747.4 — Investment in subsidiary — (1,475.3 ) — 1,475.3 — Proceeds from sale of subsidiary — — — — — Acquisition of subsidiary — — — — — Restricted cash — — — — — Other — — 3.9 — 3.9 Net cash from investing activities (589.5 ) (1,475.3 ) (839.5 ) 3,222.7 318.4 Cash Flows From Financing Activities: Issuance of external debt — 1,400.0 65.0 — 1,465.0 Repayment of external debt and capital leases — (764.5 ) (152.7 ) — (917.2 ) Debt financing costs — (12.7 ) — — (12.7 ) Proceeds from exercise of share options 4.1 — — — 4.1 Intercompany loan borrowings — 1,747.4 — (1,747.4 ) — Intercompany dividends — (1,170.0 ) (2,750.2 ) 3,920.2 — Capital contribution — — 1,475.3 (1,475.3 ) — Repurchase of shares (651.7 ) — — — (651.7 ) Other 4.1 — (21.8 ) — (17.7 ) Net cash from financing activities (643.5 ) 1,200.2 (1,384.4 ) 697.5 (130.2 ) Effect of currency rate changes on cash — — 2.5 — 2.5 Net increase (decrease) in cash, cash equivalents and restricted cash 0.2 864.3 53.5 — 918.0 Cash, cash equivalents and restricted cash at beginning of period 0.5 44.5 316.1 — 361.1 Cash, cash equivalents and restricted cash at end of period $ 0.7 $ 908.8 $ 369.6 $ — $ 1,279.1 Cash and cash equivalents at end of period $ 0.7 $ 908.8 $ 351.4 $ — $ 1,260.9 Restricted cash included in prepaid expenses and other assets at end of period — — — — — Restricted cash included in other long-term assets at end of period — — 18.2 — 18.2 Cash, cash equivalents and restricted cash at end of period $ 0.7 $ 908.8 $ 369.6 $ — $ 1,279.1 MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS Fiscal year ended September 30, 2016 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Cash Flows From Operating Activities: Net cash from operating activities $ 17.9 $ (47.4 ) $ 1,214.1 $ — $ 1,184.6 Cash Flows From Investing Activities: Capital expenditures — — (182.9 ) — (182.9 ) Acquisitions and intangibles, net of cash acquired — — (245.4 ) — (245.4 ) Proceeds from disposal of discontinued operations, net of cash — 234.0 32.7 — 266.7 Intercompany loan investment — (175.2 ) (1,714.5 ) 1,889.7 — Investment in subsidiary — (861.2 ) — 861.2 — Proceeds from sale of subsidiary 3.4 — — (3.4 ) — Acquisition of subsidiary — — (3.4 ) 3.4 — Other — — 6.0 — 6.0 Net cash from investing activities 3.4 (802.4 ) (2,107.5 ) — 2,750.9 (155.6 ) Cash Flows From Financing Activities: Issuance of external debt — — 98.3 — 98.3 Repayment of external debt and capital leases — (549.2 ) (19.4 ) — (568.6 ) Debt financing costs — — (0.1 ) — (0.1 ) Proceeds from exercise of share options 14.0 — — — 14.0 Intercompany loan borrowings 617.8 1,271.9 — (1,889.7 ) — Capital contribution — — 861.2 (861.2 ) — Repurchase of shares (652.9 ) — — — (652.9 ) Other — — (53.0 ) — (53.0 ) Net cash from financing activities (21.1 ) 722.7 — 887.0 (2,750.9 ) (1,162.3 ) Effect of currency rate changes on cash — — 0.3 — 0.3 Net increase (decrease) in cash, cash equivalents and restricted cash 0.2 (127.1 ) (6.1 ) — (133.0 ) Cash, cash equivalents and restricted cash at beginning of period 0.1 152.1 280.4 — 432.6 Cash, cash equivalents and restricted cash at end of period $ 0.3 $ 25.0 $ 274.3 $ — $ 299.6 Cash and cash equivalents at end of period $ 0.3 $ 25.0 $ 255.2 $ — $ 280.5 Restricted cash included in prepaid expenses and other assets at end of period — — 0.1 — 0.1 Restricted cash included in other long-term assets at end of period — — 19.0 — 19.0 Cash, cash equivalents and restricted cash at end of period $ 0.3 $ 25.0 $ 274.3 $ — $ 299.6 MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS Fiscal year ended September 25, 2015 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Cash Flows From Operating Activities: Net cash from operating activities $ 207.0 $ (148.2 ) $ 871.7 $ — $ 930.5 Cash Flows From Investing Activities: Capital expenditures — — (148.0 ) — (148.0 ) Acquisitions and intangibles, net of cash acquired — — (2,154.7 ) — (2,154.7 ) Intercompany loan investment (149.4 ) — (554.2 ) 703.6 — Subsidiary dividend proceeds — — — — — Investment in subsidiary — (3,014.4 ) — 3,014.4 — Other — — 3.0 — 3.0 Net cash from investing activities (149.4 ) (3,014.4 ) (2,853.9 ) — 3,718.0 (2,299.7 ) Cash Flows From Financing Activities: Issuance of external debt — 2,890.0 120.0 — 3,010.0 Repayment of external debt and capital leases — (258.3 ) (1,590.1 ) — (1,848.4 ) Debt financing costs — (39.1 ) (0.8 ) — (39.9 ) Proceeds from exercise of share options 34.4 — — — 34.4 Subsidiary dividend payment — — — — — Intercompany loan borrowings — 703.6 — (703.6 ) — Capital contribution — — 3,014.4 (3,014.4 ) — Repurchase of shares (92.2 ) — — — (92.2 ) Other — — (28.1 ) — (28.1 ) Net cash from financing activities (57.8 ) 3,296.2 — 1,515.4 (3,718.0 ) 1,035.8 Effect of currency rate changes on cash — — (11.6 ) — (11.6 ) Net (decrease) increase in cash, cash equivalents and restricted cash (0.2 ) 133.6 (478.4 ) — (345.0 ) Cash, cash equivalents and restricted cash at beginning of period 0.3 18.5 758.8 — 777.6 Cash, cash equivalents and restricted cash at end of period $ 0.1 $ 152.1 $ 280.4 $ — $ 432.6 Cash and cash equivalents at end of period $ 0.1 $ 152.1 $ 213.7 $ — $ 365.9 Restricted cash included in prepaid expenses and other assets at end of period — — 47.7 — 47.7 Restricted cash included in other long-term assets at end of period — — 19.0 — 19.0 Cash, cash equivalents and restricted cash at end of period $ 0.1 $ 152.1 $ 280.4 $ — $ 432.6 MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS Three months ended December 30, 2016 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Cash Flows From Operating Activities: Net cash from operating activities $ 17.4 $ (94.0 ) $ 272.2 $ — $ 195.6 Cash Flows From Investing Activities: Capital expenditures — — (65.2 ) — (65.2 ) Acquisitions and intangibles, net of cash acquired — — (1.8 ) — (1.8 ) Intercompany loan investment — — (424.7 ) 424.7 — Subsidiary dividend proceeds — — — — — Investment in subsidiary — (260.0 ) — 260.0 — Other — — (10.2 ) — (10.2 ) Net cash from activities — (260.0 ) (501.9 ) — 684.7 (77.2 ) Cash Flows From Financing Activities: Issuance of external debt — 175.0 15.0 — 190.0 Repayment of external debt and capital leases — (86.2 ) (0.5 ) — (86.7 ) Debt financing costs — — — — — Proceeds from exercise of share options 0.4 — — — 0.4 Subsidiary dividend payment — — — — — Intercompany loan borrowings 140.0 284.7 — (424.7 ) — Capital contribution — — 260.0 (260.0 ) — Repurchase of shares (158.8 ) — — — (158.8 ) Other 1.2 — — — 1.2 Net cash from financing activities (17.2 ) 373.5 — 274.5 (684.7 ) (53.9 ) Effect of currency rate changes on cash — — (3.0 ) — (3.0 ) Net increase in cash, cash equivalents and restricted cash 0.2 19.5 41.8 — 61.5 Cash, cash equivalents and restricted cash at beginning of period 0.3 25.0 274.3 — 299.6 Cash, cash equivalents and restricted cash at end of period $ 0.5 $ 44.5 $ 316.1 $ — $ 361.1 Cash and cash equivalents at end of period $ 0.5 $ 44.5 $ 297.0 $ — $ 342.0 Restricted cash included in prepaid expenses and other assets at end of period — — 0.1 — 0.1 Restricted cash included in other long-term assets at end of period — — 19.0 — 19.0 Cash, cash equivalents and restricted cash at end of period $ 0.5 $ 44.5 $ 316.1 $ — $ 361.1

Subsequent Events (Notes)

Subsequent Events (Notes)	12 Months Ended
	Dec. 29, 2017
Subsequent Event [Line Items]
Subsequent Events [Text Block]	24. Subsequent Events Discontinued Operations and Divestitures On January 8, 2018, the Company announced that it entered into a definitive agreement to sell its PreveLeak and Recothrom assets to Baxter International, Inc ("Baxter") for approximately $185.0 million , with upfront payment of $153.0 million , inclusive of existing inventory, and the remainder in potential future milestones. Baxter will assume other expenses, including contingent liabilities associated with PREVELEAK®. Baxter is a global medical products company that is committed to advancing surgical innovation with a variety of products and delivery devices used in the surgical suite. The Company expects the sale to close in the first quarter of 2018. On February 22, 2018, the Company’s Board of Directors authorized commencement of a process to dispose of (1) the Company’s Specialty Generics business comprised of its Specialty Generics segment, with the exception of its external manufacturing operations, (2) certain of the Company’s non-promoted brands business, which is currently reflected in the Specialty Brands segment; and (3) the Company's ongoing, post-divestiture supply agreement with the acquirer of the CMDS business, which is currently reflected in the Other non-operating segment (referred to collectively as the “Specialty Generics Disposal Group”). The Company evaluated the criteria prescribed by GAAP for recording a disposal group as held for sale and discontinued operations. This criteria was not met as of December 29, 2017. Therefore, this disposal group was not presented as a discontinued operation in the accompanying consolidated balance sheets and consolidated statements of income. Beginning in the first quarter of fiscal 2018, the historical financial results attributable to the Specialty Generics Disposal Group will be reflected in the Company’s consolidated financial statements as discontinued operations. Sucampo Acquisition On February 13, 2018, the Company acquired Sucampo Pharmaceuticals, Inc. ("Sucampo"). Consideration for the transaction consisted of approximately $1.2 billion , including the assumption of Sucampo's third-party debt ("the Sucampo Acquisition"). The acquisition was funded through the issuance of $600.0 million aggregate principal amount of senior secured notes (as discussed further below), a $900.0 million borrowing under the Revolver and cash on hand. Sucampo's commercialized products include AMITIZA® (lubiprostone), a leading global product in the branded constipation market, and RESCULA® (unoprostone isopropyl ophthalmic solution) 0.15%, which is indicated for ocular hypertension and open-angle glaucoma, and marketed in Japan. In addition, Sucampo has two pipeline products that are currently in Phase 3 development: VTS-270, a development product for Niemann-Pick Type C, a rare, neurodegenerative, and ultimately fatal disease that can present at any age, and CPP-1X/sulindac, a development product for Familial Adenomatous Polyposis under a collaborative agreement between Cancer Prevention pharmaceuticals and Sucampo. The Company incurred acquisition costs within the consolidated statements of income for fiscal 2017 of $4.2 million , which were included within SG&A. The Company has not yet completed a preliminary allocation of the total consideration to the identifiable assets acquired and liabilities assumed for the Sucampo Acquisition. However, the Company expects that significant assets acquired will primarily consist of intangible assets, but will also include inventory adjusted to fair value, and that significant liabilities assumed will include the existing Sucampo third-party debt and deferred tax liabilities associated with assets acquired. The Company expects to complete a preliminary allocation of the total consideration during the first quarter of fiscal 2018. Upon completion of the Sucampo Acquisition, Sucampo’s 3.25% convertible senior notes due 2021 (“the Sucampo Notes”) became eligible to receive increased consideration in conjunction with a make-whole fundamental change, such that each $1,000 principal face amount of Sucampo notes may be converted into $1,221 cash. Under terms of the Indenture dated December 27, 2016 (the “Sucampo Indenture”), between Sucampo and U.S. Bank National Association, the Sucampo Notes may be converted at the option of their holders and be eligible to receive increased consideration during a period of time following consummation of the merger transaction, or remain outstanding and earn the stated 3.25% rate of interest. It is the expectation that all holders will eventually exercise their conversion rights under the Sucampo Indenture. At the time of this filing approximately $73.5 million of the $300.0 million of issued convertible debt remains outstanding. Sucampo Acquisition Financing In February 2018, in conjunction with the Sucampo Acquisition, the Company entered into a $600.0 million senior secured term loan. The variable-rate loan bears an interest rate of LIBOR plus 300 basis points and was issued with a discount of 25 basis points. The incremental term loan matures on February 25, 2025 under terms generally consistent with the Company's existing term loan. Financing Activities On January 16, 2018, the Company made a $225.0 million voluntary prepayment on its outstanding term loan. In making this payment the Company satisfies certain obligations included within external debt agreements to reinvest proceeds from the sale of assets and businesses within one year of the respective transaction or use the proceeds to pay down debt. On February 21, 2018, the Company borrowed an additional $25.0 million on its Receivable Securitization, bringing total outstanding borrowings to $225.0 million for this instrument. The Company also made a $275.0 million payment on the 2017 Revolving Credit Facility, bringing total outstanding borrowings to $625.0 million for this instrument. Commitments and Contingencies Certain litigation matters occurred in fiscal 2017 or prior, but had subsequent updates in January and February 2018. See further discussion in Note 19 to the consolidated financial statements.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts (Notes)	12 Months Ended
	Dec. 29, 2017
Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	Financial Statement Schedules. The financial statement schedule is included below. All other schedules have been omitted because they are not applicable, not required or the information is included in the financial statements or notes thereto. Schedule II - Valuation and Qualifying Accounts (in millions) Description Balance at Beginning of Period Charged to Income Additions and Other Deductions Balance at End of Period Allowance for doubtful accounts: Fiscal year ended December 29, 2017 $ 4.0 $ 0.6 $ — $ (0.7 ) $ 3.9 Three months ended December 30, 2016 4.0 0.1 — (0.1 ) 4.0 Fiscal year ended September 30, 2016 3.6 0.3 — 0.1 4.0 Fiscal year ended September 25, 2015 2.2 1.2 — 0.2 3.6 Sales reserve accounts: Fiscal year ended December 29, 2017 $ 391.3 $ 2,008.5 $ — $ (2,023.2 ) $ 376.6 Three months ended December 30, 2016 378.0 515.3 — (502.0 ) 391.3 Fiscal year ended September 30, 2016 396.4 2,030.8 — (2,049.2 ) 378.0 Fiscal year ended September 25, 2015 402.2 2,177.4 1.3 (2,184.5 ) 396.4 Tax valuation allowance: Fiscal year ended December 29, 2017 $ 1,398.3 $ 804.6 $ 4.0 $ 61.0 $ 2,267.9 Three months ended December 30, 2016 564.9 833.4 — — 1,398.3 Fiscal year ended September 30, 2016 233.0 315.7 15.8 0.4 564.9 Fiscal year ended September 25, 2015 76.9 155.4 0.2 0.5 233.0

Background and Basis of Prese35

Background and Basis of Presentation (Policies)	12 Months Ended
	Dec. 29, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Accounting	The consolidated financial statements have been prepared in U.S. dollars and in accordance with accounting principles generally accepted in the U.S. ("GAAP").
Use of Estimates	The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amount of assets and liabilities, disclosure of contingent assets and liabilities and the reported amounts of revenues and expenses. Actual results may differ from those estimates.
Consolidation	The consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries and entities in which they own or control more than 50% of the voting shares, or have the ability to control through similar rights. All intercompany balances and transactions have been eliminated in consolidation and all normal recurring adjustments necessary for a fair presentation have been included in the results reported.
Fiscal Period	Fiscal Year The Company historically reported its results based on a "52-53 week" year ending on the last Friday of September. On May 17, 2016, the Board of Directors of the Company approved a change in the Company’s fiscal year end to the last Friday in December from the last Friday in September. The change in fiscal year became effective for the Company’s 2017 fiscal year, which began on December 31, 2016 and ended on December 29, 2017. As a result of the change in fiscal year end, the Company filed a Transition Report on Form 10-Q on February 7, 2017 covering the period from October 1, 2016 through December 30, 2016 ("the three months ended December 30, 2016") with the comparable period from September 26, 2015 through December 25, 2015. Fiscal 2016 covers the period from September 26, 2015 through September 30, 2016 and fiscal 2015 covers the period from September 27, 2014 through September 25, 2015.

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 29, 2017
Accounting Policies [Abstract]
Revenue Recognition	Revenue Recognition The Company recognizes revenue for product sales when title and risk of loss have transferred from the Company to the buyer, which may be upon shipment, delivery to the customer site, consumption of the product by the customer, or over the period in which the customer has access to the product and any related services, based on contract terms or legal requirements in non-U.S. jurisdictions. The Company sells products through independent channels, including directly to retail pharmacies, end user customers and through distributors who resell the products to retail pharmacies, institutions and end user customers. Certain products are sold and distributed directly to hospitals. Chargebacks and rebates are provided to certain distributors and customers for either the difference between the Company's contracted price with a customer and the distributor's invoice price paid to the Company or for contractually agreed discounts. When the Company recognizes net sales, it simultaneously records an adjustment to revenue for estimated chargebacks, rebates, product returns and other sales deductions. These provisions are estimated based upon historical experience, estimated future trends, estimated customer inventory levels, current contracted sales terms with customers, level of utilization of the Company's products and other competitive factors. The Company adjusts these reserves to reflect differences between estimated activity and actual experience. Such adjustments impact the amount of net sales recognized by the Company in the period of adjustment. Taxes collected from customers relating to product sales and remitted to governmental authorities are accounted for on a net basis. Accordingly, such taxes are excluded from both net sales and expenses.
Shipping and Handling Costs	Shipping and Handling Costs Shipping costs, which are costs incurred to physically move product from the Company's premises to the customer's premises, are classified as selling, general and administrative expenses. Handling costs, which are costs incurred to store, move and prepare product for shipment, are classified as cost of sales.
Research and Development	Research and Development Internal research and development costs are expensed as incurred. Research and development expenses include salary and benefits, allocated overhead and occupancy costs, clinical trial and related clinical manufacturing costs, contract services, medical affairs and other costs. Upfront and milestone payments made to third parties under license arrangements are expensed as incurred up to the point of regulatory approval of the product. Milestone payments made to third parties upon or subsequent to regulatory approval are capitalized as an intangible asset and amortized to cost of sales over the estimated useful life of the related product.
Currency Translation	Currency Translation For the Company's non-U.S. subsidiaries that transact in a functional currency other than U.S. dollars, assets and liabilities are translated into U.S. dollars using fiscal year-end exchange rates. Revenues and expenses are translated at the average exchange rates in effect during the related month. The net effect of these translation adjustments is shown in the consolidated financial statements as a component of accumulated other comprehensive income. For subsidiaries operating in highly inflationary environments or where the functional currency is different from the local currency, non-monetary assets and liabilities are translated at the rate of exchange in effect on the date the assets and liabilities were acquired or assumed, while monetary assets and liabilities are translated at fiscal year-end exchange rates. Translation adjustments of these subsidiaries are included in net income. Gains and losses resulting from foreign currency transactions are included in net income.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company classifies cash on hand and deposits in banks, including commercial paper, money market accounts and other investments it may hold from time to time, with an original maturity to the Company of three months or less, as cash and cash equivalents.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts Trade accounts receivable are presented net of an allowance for doubtful accounts. The allowance for doubtful accounts reflects an estimate of losses inherent in the Company's accounts receivable portfolio determined on the basis of historical experience, specific allowances for known troubled accounts and other available evidence. Accounts receivable are written off when management determines they are uncollectible. Trade accounts receivable are also presented net of reserves related to chargebacks and rebates payable to customers for whom the Company has trade accounts receivable and the right of offset exists.
Inventories	Inventories Inventories are recorded at the lower of cost or net realizable value, primarily using the first-in, first-out convention. The Company reduces the carrying value of inventories for those items that are potentially excess, obsolete or slow-moving based on changes in customer demand, technology developments or other economic factors.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are stated at cost. Major renewals and improvements are capitalized, while routine maintenance and repairs are expensed as incurred. Depreciation for property, plant and equipment assets, other than land and construction in process, is generally based upon the following estimated useful lives, using the straight-line method: Buildings 10 to 45 years Leasehold improvements 1 to 20 years Capitalized software 1 to 10 years Machinery and equipment 1 to 20 years The Company capitalizes certain computer software and development costs incurred in connection with developing or obtaining software for internal use. Upon retirement or other disposal of property, plant and equipment, the cost and related amount of accumulated depreciation are eliminated from the asset and accumulated depreciation accounts, respectively. The difference, if any, between the net asset value and the proceeds is included in net income. The Company assesses the recoverability of assets or asset groups using undiscounted cash flows whenever events or circumstances indicate that the carrying value of an asset or asset group may not be recoverable. If an asset or asset group is found to be impaired, the amount recognized for impairment is equal to the difference between the carrying value of the asset or asset group and its fair value.
Acquisitions	Acquisitions Amounts paid for acquisitions are allocated to the tangible assets acquired and liabilities assumed based on their estimated fair values at the date of acquisition. The Company then allocates the purchase price in excess of net tangible assets acquired to identifiable intangible assets, including purchased R&D. The fair value of identifiable intangible assets is based on detailed valuations. The Company allocates any excess purchase price over the fair value of the net tangible and intangible assets acquired to goodwill. The Company's purchased R&D represents the estimated fair value as of the acquisition date of in-process projects that have not reached technological feasibility. The primary basis for determining technological feasibility of these projects is obtaining regulatory approval. The fair value of in-process research and development ("IPR&D") is determined using the discounted cash flow method. In determining the fair value of IPR&D, the Company considers, among other factors, appraisals, the stage of completion of the projects, the technological feasibility of the projects, whether the projects have an alternative future use and the estimated residual cash flows that could be generated from the various projects and technologies over their respective projected economic lives. The discount rate used includes a rate of return which accounts for the time value of money, as well as risk factors that reflect the economic risk that the cash flows projected may not be realized. The fair value attributable to IPR&D projects at the time of acquisition is capitalized as an indefinite-lived intangible asset and tested annually for impairment until the project is completed or abandoned. Upon completion of the project, the indefinite-lived intangible asset is then accounted for as a finite-lived intangible asset and amortized on a straight-line basis over its estimated useful life. If the project is abandoned, the indefinite-lived intangible asset is charged to expense.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill represents the excess of the purchase price of an acquired entity over the amounts assigned to assets and liabilities assumed in a business combination. The Company tests goodwill for impairment on the first day of the fourth quarter of each fiscal year, or whenever events or changes in circumstances indicate that the carrying value may not be recoverable. The impairment test is comprised of comparing the carrying value of a reporting unit to its estimated fair value. The Company estimates the fair value of a reporting unit through internal analyses and valuation, utilizing an income approach (a level three measurement technique) based on the present value of future cash flows. If the carrying value of a reporting unit exceeds its fair value, the Company will recognize the excess of the carrying value over the fair value as a goodwill impairment loss. Intangible assets acquired in a business combination are recorded at fair value, while intangible assets acquired in other transactions are recorded at cost. Intangible assets with finite useful lives are subsequently amortized, generally using the straight-line method, over the following estimated useful lives of the assets, except for customer relationships which are amortized over the estimated pattern of benefit from these relationships: Completed technology 5 to 25 years License agreements 7 to 30 years Trademarks 13 to 30 years Customer relationships 12 years Amortization expense related to completed technology and certain other intangible assets is included in cost of sales, while amortization expense related to intangible assets that contribute to the Company's ability to sell, market and distribute products is included in SG&A. When a triggering event occurs, the Company evaluates potential impairment of finite-lived intangible assets by first comparing undiscounted cash flows associated with the asset, or the asset group they are part of, to its carrying value. If the carrying value is greater than the undiscounted cash flows, the amount of potential impairment is measured by comparing the fair value of the assets, or the asset group they are part of, with their carrying value. The fair value of the intangible asset, or the asset group they are part of, is estimated using an income approach. If the fair value is less than the carrying value of the intangible asset, or the asset group they are part of, the amount recognized for impairment is equal to the difference between the carrying value of the asset and the fair value of the asset. The Company assesses the remaining useful life and the recoverability of finite-lived intangible assets whenever events or circumstances indicate that the carrying value of an asset may not be recoverable. The Company annually tests the indefinite-lived intangible assets for impairment, or whenever events or changes in circumstances indicate that the carrying value may not be recoverable by either a qualitative or income approach. The Company will compare the fair value of the assets with their carrying value and record an impairment when the carrying value exceeds the fair value.
Contingencies	Contingencies The Company is subject to various patent infringement, product liability, government investigations, environmental matters and other legal proceedings in the ordinary course of business. The Company records accruals for contingencies when it is probable that a liability has been incurred and the amount can be reasonably estimated. The Company discounts environmental liabilities using a risk-free rate of return when the obligation is fixed or reasonably determinable. The impact of the discount in the consolidated balance sheets was not material in any period presented. Legal fees, other than those pertaining to environmental and asbestos matters, are expensed as incurred. Insurance recoveries related to potential claims are recognized up to the amount of the recorded liability when coverage is confirmed and the estimated recoveries are probable of payment. Assets and liabilities are not netted for financial statement presentation.
Share-Based Compensation	Share-Based Compensation The Company recognizes the cost of employee services received in exchange for awards of equity instruments based on the grant-date fair value of those awards. That cost is recognized over the period during which an employee is required to provide service in exchange for the award, the requisite service period (generally the vesting period).
Restructuring	Restructuring The Company recognizes charges associated with board approved restructuring programs designed to transform its business and improve its cost structure. Restructuring charges can include severance costs, infrastructure charges, distributor contract cancellations and other items. The Company records restructuring charges based on estimated consolidation plans and accrues for costs when they are probable and reasonably estimable.
Income Taxes	Income Taxes Deferred tax assets and liabilities are recognized for the expected future tax consequences of events that have been reflected in the consolidated financial statements. Deferred tax assets and liabilities are determined based on the differences between the book and tax bases of assets and liabilities and operating loss carryforwards, using tax rates expected to be in effect for the years in which the differences are expected to reverse. A valuation allowance is provided to reduce net deferred tax assets if, based upon the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. Deferred tax liabilities are also recorded for deferred tax obligations related to installment sale arrangements. The deferral of tax payments to the U.S. Internal Revenue Service ("IRS") are subject to interest, which is accrued and included within interest expense. The Company determines whether it is more likely than not that a tax position will be sustained upon examination. The tax benefit of any tax position that meets the more-likely-than-not recognition threshold is calculated as the largest amount that is more than 50% likely of being realized upon resolution of the uncertainty. To the extent a full benefit is not expected to be realized on the uncertain tax position, an income tax liability is established. Interest and penalties on income tax obligations, associated with uncertain tax positions, are included in the provision for income taxes. The calculation of the Company's tax liabilities involves dealing with uncertainties in the application of complex tax regulations in a multitude of jurisdictions across the Company's global operations. Due to the complexity of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from current estimates of the tax liabilities. If the Company's estimate of tax liabilities proves to be less than the ultimate assessment, an additional charge to expense would result. If payment of these amounts ultimately proves to be less than the recorded amounts, the reversal of the liabilities may result in income tax benefits being recognized in the period when it is determined that the liabilities are no longer necessary. A significant portion of these potential tax liabilities are recorded in other income tax liabilities on the consolidated balance sheets as payment is not expected within one year.

Earnings (Loss) per Share (Poli

Earnings (Loss) per Share (Policies)	12 Months Ended
	Dec. 29, 2017
Earnings (Loss) per Share [Abstract]
Earnings (Loss) Per Share Policy	Basic earnings (loss) per share is computed by dividing net income by the number of weighted-average shares outstanding during the period. Diluted earnings (loss) per share was computed using the weighted-average shares outstanding and, if dilutive, potential ordinary shares outstanding during the period. Potential ordinary shares represent the incremental ordinary shares issuable for restricted share units and share option exercises. The Company calculated the dilutive effect of outstanding restricted share units and share options on earnings (loss) per share by application of the treasury stock method. In fiscal 2015 and years prior, basic and diluted earnings (loss) per share were computed using the two-class method. The two-class method is an earnings allocation that determines earnings per share for each class of common stock and participating securities according to dividends declared and participation rights in undistributed earnings. The Company’s restricted stock awards, issued in conjunction with the acquisition of Questcor in August 2014 ("the Questcor Acquisition"), were considered participating securities as holders were entitled to receive non-forfeitable dividends during the vesting term. Diluted earnings per share included securities that could potentially dilute basic earnings per share during a reporting period, for which the Company includes all share-based compensation awards other than participating securities. Dilutive securities, including participating securities, are not included in the computation of loss per share when the Company reports a net loss from continuing operations as the impact would be anti-dilutive.

Summary of Significant Accoun38

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 29, 2017
Accounting Policies [Abstract]
Schedule of Useful Lives for Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are stated at cost. Major renewals and improvements are capitalized, while routine maintenance and repairs are expensed as incurred. Depreciation for property, plant and equipment assets, other than land and construction in process, is generally based upon the following estimated useful lives, using the straight-line method: Buildings 10 to 45 years Leasehold improvements 1 to 20 years Capitalized software 1 to 10 years Machinery and equipment 1 to 20 years The Company capitalizes certain computer software and development costs incurred in connection with developing or obtaining software for internal use. Upon retirement or other disposal of property, plant and equipment, the cost and related amount of accumulated depreciation are eliminated from the asset and accumulated depreciation accounts, respectively. The difference, if any, between the net asset value and the proceeds is included in net income. The Company assesses the recoverability of assets or asset groups using undiscounted cash flows whenever events or circumstances indicate that the carrying value of an asset or asset group may not be recoverable. If an asset or asset group is found to be impaired, the amount recognized for impairment is equal to the difference between the carrying value of the asset or asset group and its fair value.
Schedule of Useful Lives for Finite Lived Intangible Assets	Intangible assets with finite useful lives are subsequently amortized, generally using the straight-line method, over the following estimated useful lives of the assets, except for customer relationships which are amortized over the estimated pattern of benefit from these relationships: Completed technology 5 to 25 years License agreements 7 to 30 years Trademarks 13 to 30 years Customer relationships 12 years
Shipping and Handling Cost	Shipping costs included in SG&A expenses in continuing operations were as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Shipping and handling costs $ 13.9 $ 12.4 $ 11.6 $ 3.4

Discontinued Operations and D39

Discontinued Operations and Divestitures (Tables)	12 Months Ended
	Dec. 29, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Schedule of Income (Loss) from Discontinued Operations	The following table summarizes the financial results of the CMDS business for fiscal 2017, 2016 and 2015 and the three months ended December 30, 2016 as presented in the consolidated statements of income: Fiscal Year Ended Three Months Ended Major line items constituting (loss) income from discontinued operations December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Net sales $ — $ 61.0 $ 413.8 $ — Cost of sales — 46.9 306.4 — Selling, general and administrative — 20.3 97.5 — Restructuring charges, net — — 0.3 — Other — 1.2 4.7 — (Loss) income from discontinued operations — (7.4 ) 4.9 — Gain on disposal of discontinued operations — 95.3 — — (Loss) income from discontinued operations, before income taxes — 87.9 4.9 — Income tax (benefit) expense — (2.5 ) 10.8 — (Loss) income from discontinued operations net of tax $ — $ 90.4 $ (5.9 ) $ — The following table summarizes the financial results of the Nuclear Imaging business for fiscal years 2017, 2016 and 2015 and the three months ended December 30, 2016 as presented in the consolidated statements of income: Fiscal Year Ended Three Months Ended Major line items constituting income from discontinued operations December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Net sales $ 31.6 $ 418.6 $ 423.8 $ 99.4 Cost of sales 15.6 216.6 193.1 44.7 Selling, general and administrative 7.8 83.7 89.6 16.4 Restructuring charges, net — 2.3 (4.6 ) — Other (0.2 ) 5.7 37.7 0.2 Income from discontinued operations 8.4 110.3 108.0 38.1 Gain on disposal of discontinued operations 362.8 — — — Income from discontinued operations, before income taxes 371.2 110.3 108.0 38.1 Income tax expense 5.2 49.0 36.4 15.3 Income from discontinued operations, net of tax $ 366.0 $ 61.3 $ 71.6 $ 22.8
Schedule of Assets and Liabilities Held-For-Sale	The following table summarizes the assets and liabilities of the Nuclear Imaging business that are classified as held for sale on the consolidated balance sheets at the end of each period: December 29, 2017 December 30, 2016 Carrying amounts of major classes of assets included as part of discontinued operations Accounts receivable $ — $ 49.6 Inventories — 20.0 Property, plant and equipment, net — 188.7 Other current and non-current assets — 52.6 Total assets classified as held for sale in the balance sheet $ — $ 310.9 Carrying amounts of major classes of liabilities included as part of discontinued operations Accounts payable $ — $ 19.7 Other current and non-current liabilities — 100.6 Total liabilities classified as held for sale in the balance sheet $ — $ 120.3
Schedule of Significant Cash and Non-Cash Transactions	The following table summarizes significant cash and non-cash transactions of the Nuclear Imaging business that are included within the consolidated statements of cash flows for the fiscal years 2017, 2016 and 2015 and the three months ended December 30, 2016: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Depreciation $ — $ 20.9 $ 13.1 $ — Capital expenditures 0.3 9.7 7.6 2.0 The following table summarizes significant cash and non-cash transactions of the CMDS business that are included within the consolidated statements of cash flows for the fiscal years 2017, 2016 and 2015 and the three months ended December 30, 2016: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Depreciation $ — $ — $ 15.5 $ — Amortization — — 2.3 — Capital expenditures — 1.6 9.5 —

Acquisitions and License Agre40

Acquisitions and License Agreements (Tables)	12 Months Ended
	Dec. 29, 2017
Business Combinations [Abstract]
Schedule of Fair Value of Identifiable Assets Acquired and Liabilities Assumed	The following amounts represent the allocation of the fair value of the identifiable assets acquired and liabilities assumed for the respective acquisitions: Ocera (2) InfaCare (2) Stratatech Hemostasis (1) Therakos Ikaria Acquisition Date December 2017 September 2017 August 2016 February 2016 September 2015 April 2015 Cash $ 1.0 $ 1.3 $ 0.2 $ 3.3 $ 41.3 $ 77.3 Accounts receivable — — 1.3 — 22.0 73.8 Inventory — — — 94.6 23.5 26.3 Intangible assets 64.5 113.5 99.8 132.7 1,170.0 1,971.0 Goodwill (non-tax deductible) 25.1 11.4 55.1 3.3 429.9 795.0 Other assets, current and non-current 0.4 0.1 1.9 7.9 18.2 100.5 Total assets acquired 91.0 126.3 158.3 241.8 1,704.9 3,043.9 Current liabilities 14.5 14.5 4.3 3.6 24.7 33.0 Other liabilities (non-current) — — — 10.6 0.6 15.8 Deferred tax liabilities, net (non-current) 23.2 8.7 22.1 2.1 315.7 620.5 Contingent consideration (non-current) 12.8 35.0 54.9 52.0 — — Total debt — 30.0 1.0 — 344.8 1,121.0 Total liabilities assumed 50.5 88.2 82.3 68.3 685.8 1,790.3 Net assets acquired $ 40.5 $ 38.1 $ 76.0 $ 173.5 $ 1,019.1 $ 1,253.6 (1) During fiscal 2017, the Company recorded a non-restructuring impairment charge relating to one of its intangible assets and reduced the associated contingent consideration. Refer to Note 12 and 20, respectively, for further information. (2) The fair value allocations for these acquisitions are preliminary and subject to measurement period adjustments.	[1],[2]
Schedule of Reconciliation of Total Consideration	The following reconciles the total consideration to net assets acquired: Ocera InfaCare Stratatech Hemostasis Therakos Ikaria Total consideration, net of cash $ 63.4 $ 71.8 $ 130.7 $ 222.2 $ 977.8 $ 1,176.3 Plus: cash assumed in acquisition 1.0 1.3 0.2 3.3 41.3 77.3 Total consideration 64.4 73.1 130.9 225.5 1,019.1 1,253.6 Less: unpaid purchase consideration (1.9 ) — — — — — Less: non-cash contingent consideration (22.0 ) (35.0 ) (54.9 ) (52.0 ) — — Net assets acquired $ 40.5 $ 38.1 $ 76.0 $ 173.5 $ 1,019.1 $ 1,253.6
Schedule of Earnings by Acquiree	Financial Results - The amount of net sales and earnings included in the Company's results for the periods presented were as follows: Fiscal Year Ended Three Months Ended Net sales December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Ocera $ — $ — $ — $ — InfaCare — — — — Therakos 214.9 207.6 — 47.4 Ikaria 515.1 491.5 191.9 121.4 Total $ 730.0 $ 699.1 $ 191.9 $ 168.8 Operating income Ocera $ (0.4 ) $ — $ — $ — InfaCare (5.4 ) — — — Therakos 27.0 12.5 — 9.2 Ikaria 202.8 201.1 47.1 51.0 Total $ 224.0 $ 213.6 $ 47.1 $ 60.2
Schedule of Acquisition Cost	Acquisition-Related Costs - Acquisition-related costs incurred for each of the acquisitions discussed above were as follows: Fiscal Year Ended Three Months Ended Acquisition-related costs December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Ocera $ 0.9 $ — $ — $ — Xenon Licensing Agreement 0.1 — — — InfaCare 1.2 — — — Stratatech — 3.7 — — Hemostasis Products — 2.7 — 0.1 Therakos — 0.3 22.5 — Ikaria — 0.2 30.9 — Total acquisition-related costs $ 2.2 $ 6.9 $ 53.4 $ 0.1
Business Combination Intangible Asset Amortization By Acquiree	The amount of amortization on acquired intangible assets included within operating income (loss) for the periods presented was as follows: Fiscal Year Ended Three Months Ended Intangible asset amortization December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Ocera $ — $ — $ — $ — InfaCare — — — — Therakos 61.7 78.0 — 19.5 Ikaria 124.5 124.5 57.1 31.1 Total $ 186.2 $ 202.5 $ 57.1 $ 50.6
Schedule of Intangible Assets Acquired	Intangible assets acquired consist of the following: Acquisition Intangible Asset Acquired Amount Amortization Period Discount Rate Ocera In-process research and development - MNK-6105 $ 64.5 Non-Amortizable 15.5 % InfaCare In-process research and development - stannsoporfin 113.5 Non-Amortizable 13.5 % Stratatech In-process research and development - StrataGraft 99.8 Non-Amortizable 16.5 % Hemostasis Completed technology - Raplixa (1) 73.0 15 years 17.0 % Hemostasis Completed technology - Recothrom 42.7 13 years 16.0 % Hemostasis Completed technology - PreveLeak 17.0 13 years 17.0 % Therakos Completed technology - Extracorporeal photopheresis treatment therapies 1,170.0 15 years 17.0 % Ikaria Completed technology 1,820.0 15 years 14.5 % Ikaria Trademark 70.0 22 years 14.5 % Ikaria In-process research and development - Terlipressin 81.0 Non-Amortizable 17.0 % (1) During fiscal 2017, the Company recorded a non-restructuring impairment charge relating to the Raplixa intangible asset. Refer to Note 12 for further information.	[3]
[1]	(1)During fiscal 2017, the Company recorded a non-restructuring impairment charge relating to one of its intangible assets and reduced the associated contingent consideration. Refer to Note 12 and 20, respectively, for further information.
[2]	(2)The fair value allocations for these acquisitions are preliminary and subject to measurement period adjustments.
[3]	(1)During fiscal 2017, the Company recorded a non-restructuring impairment charge relating to the Raplixa intangible asset. Refer to Note 12 for further information.

Restructuring and Related Cha41

Restructuring and Related Charges (Tables)	12 Months Ended
	Dec. 29, 2017
Restructuring and Related Activities [Abstract]
Schedule of Restructuring and Related Charges by Segment	Net restructuring and related charges by segment from continuing operations are as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Specialty Brands $ 25.4 $ 23.3 $ 36.5 $ 2.6 Specialty Generics 7.7 3.4 4.5 0.8 Corporate 3.3 11.5 4.3 1.9 Restructuring and related charges, net 36.4 38.2 45.3 5.3 Less: accelerated depreciation (5.2 ) (4.9 ) (0.3 ) (1.5 ) Restructuring charges, net $ 31.2 $ 33.3 $ 45.0 $ 3.8
Schedule of Net Restructuring and Related Charges	Net restructuring and related charges by program from continuing operations are comprised of the following: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 2016 Mallinckrodt Program $ 36.2 $ 8.3 $ — $ 5.2 2013 Mallinckrodt Program (0.7 ) 26.2 12.0 — Acquisition programs 0.9 3.7 33.6 0.1 Other programs — — (0.3 ) — Total programs 36.4 38.2 45.3 5.3 Less: non-cash charges, including impairments and accelerated share based compensation expense (5.2 ) (4.9 ) (10.1 ) (1.5 ) Total charges expected to be settled in cash $ 31.2 $ 33.3 $ 35.2 $ 3.8
Schedule of Restructuring Reserves by Type of Cost	The following table summarizes cash activity for restructuring reserves, substantially all of which related to employee severance and benefits and exiting of certain facilities: 2016 Mallinckrodt Program 2013 Mallinckrodt Program Acquisition Programs Other Programs Total Balance at September 26, 2014 $ — $ 26.6 $ 7.9 $ 0.4 $ 34.9 Charges from continuing operations — 11.7 25.3 — 37.0 Charges from discontinued operations — 4.7 — — 4.7 Changes in estimate from continuing operations — — (1.5 ) (0.3 ) (1.8 ) Changes in estimate from discontinued operations — (8.9 ) — — (8.9 ) Cash payments — (22.5 ) (21.7 ) (0.1 ) (44.3 ) Reclassifications (1) — (3.0 ) — — (3.0 ) Currency translation — (0.6 ) — — (0.6 ) Balance at September 25, 2015 — 8.0 10.0 — 18.0 Charges from continuing operations 6.4 24.6 5.0 — 36.0 Charges from discontinued operations — 2.5 — — 2.5 Changes in estimate from continuing operations — (1.4 ) (1.3 ) — (2.7 ) Changes in estimate from discontinued operations — (0.3 ) — — (0.3 ) Cash payments (0.2 ) (20.3 ) (13.2 ) — (33.7 ) Reclassifications (1) — (1.3 ) — — (1.3 ) Balance at September 30, 2016 6.2 11.8 0.5 — 18.5 Charges from continuing operations 3.7 — 0.1 — 3.8 Cash payments (0.4 ) (6.7 ) (0.4 ) — (7.5 ) Balance at December 30, 2016 9.5 5.1 0.2 — 14.8 Charges from continuing operations 35.8 — 0.9 — 36.7 Changes in estimate from continuing operations (4.8 ) (0.7 ) — — (5.5 ) Cash payments (26.1 ) (4.4 ) (0.3 ) — (30.8 ) Reclassifications (1) 0.3 — — — 0.3 Balance at December 29, 2017 $ 14.7 $ — $ 0.8 $ — $ 15.5 (1) Represents the reclassification of pension and other postretirement benefits from restructuring reserves to pension and postretirement obligations.	[1]
Schedule of Restructuring Charges Incurred Cumulative to Date	Net restructuring and related charges, including associated asset impairments, incurred cumulative to date related to the 2016 and 2013 Mallinckrodt Programs are as follows: 2016 Mallinckrodt Program 2013 Mallinckrodt Program Specialty Brands $ 32.5 $ 18.8 Specialty Generics 9.1 18.3 Discontinued Operations (including Nuclear and CMDS) — 69.9 Corporate 9.0 17.7 $ 50.6 $ 124.7
[1]	Represents the reclassification of pension and other postretirement benefits from restructuring reserves to pension and postretirement obligations.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 29, 2017
Income Tax Disclosure [Abstract]
Schedule of Components of Income from Continuing Operations before Income Taxes	The U.K. and non-U.K. components of income (loss) from continuing operations before income taxes were as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 U.K. $ (165.9 ) $ (275.3 ) $ (107.5 ) $ (97.4 ) Non-U.K. 227.5 508.7 214.8 (201.1 ) Total $ 61.6 $ 233.4 $ 107.3 $ (298.5 )
Schedule of Significant Components of Income Taxes Related to Continuing Operations	Significant components of income taxes related to continuing operations are as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Current: U.K. $ 0.4 $ 0.3 $ 0.2 $ — Non-U.K. 37.7 120.5 67.3 82.0 Current income tax provision 38.1 120.8 67.5 82.0 Deferred: U.K. $ 0.6 $ 0.7 $ (0.8 ) $ (0.5 ) Non-U.K. (1,748.3 ) (377.1 ) (196.0 ) (203.2 ) Deferred income tax benefit (1,747.7 ) (376.4 ) (196.8 ) (203.7 ) $ (1,709.6 ) $ (255.6 ) $ (129.3 ) $ (121.7 )
Schedule of Reconciliation of Income Taxes at Statutory Rate and Tax Provision	The reconciliation between U.K. income taxes at the statutory rate and the Company's provision for income taxes on continuing operations is as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Provision (benefit) for income taxes at U.K. statutory income tax rate (1) $ 11.7 $ 46.6 $ 21.4 $ (59.7 ) Adjustments to reconcile to income tax provision: Rate difference between U.K. and non-U.K. jurisdictions (2) (5) (219.9 ) (249.3 ) (152.9 ) (123.0 ) Valuation allowances, nonrecurring (3.7 ) 2.1 (2.1 ) — Adjustments to accrued income tax liabilities and uncertain tax positions (7) 5.1 (14.9 ) (7.0 ) 0.9 Interest and penalties on accrued income tax liabilities and uncertain tax positions 0.2 (16.4 ) 0.3 (0.1 ) Investment in partnership — — — (12.7 ) Credits, principally research and orphan drug (3) (4) (13.8 ) (33.7 ) (8.1 ) (0.7 ) Impairments non deductible — — — 75.3 Permanently nondeductible and nontaxable items 6.4 7.9 14.7 1.6 Pension plan settlement, release of tax effects lodged in other comprehensive income (2.4 ) — — — Divestiture of Intrathecal Therapy Business 18.2 — — — U.S. Tax Reform (6) (456.9 ) — — — Legal Entity Reorganization (7) (1,054.8 ) — — — Other 0.3 2.1 4.4 (3.3 ) Benefit for income taxes $ (1,709.6 ) $ (255.6 ) $ (129.3 ) $ (121.7 ) (1) The statutory tax rate reflects the U.K. statutory tax rate of 19% for fiscal 2017 and 20% for fiscal 2016, 2015 and the three months ended December 30, 2016. (2) Includes the impact of certain recurring valuation allowances for U.K. and non-U.K. jurisdictions. (3) During fiscal 2015, the Research Credit tax law was extended, with a retroactive effective date of January 1, 2014. As such, fiscal 2015 includes approximately $3.6 million of credit related to the period January 1, 2014 through September 26, 2014. (4) During fiscal 2016, the Company realized a tax benefit of $27.4 million resulting from a U.K. tax credit on a dividend between affiliates. (5) During the three months ended December 30, 2016, the rate difference between U.K. and non-U.K. jurisdictions was favorably impacted by a benefit of $16.1 million on a $102.0 million settlement with the Federal Trade Commission and a benefit of $34.5 million on a $207.0 million goodwill impairment in the Specialty Generics segment. (6) Reflects redetermination of the Company's deferred tax liabilities as a result of the new U.S. statutory income tax rate of 21% at the date of enactment. Other line items, to the extent U.S. related, are reflected at the former U.S. statutory income tax rate of 35%. (7) Associated unrecognized tax benefit netted within this line.	[1],[2],[3],[4],[5],[6],[7]
Schedule of Unrecognized Tax Benefit Activity	The following table summarizes the activity related to the Company's unrecognized tax benefits, excluding interest: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Balance at beginning of period $ 118.7 $ 89.2 $ 82.0 $ 114.8 Additions related to current year tax positions 79.9 63.8 4.5 5.0 Additions related to prior period tax positions 0.3 10.8 19.9 — Reductions related to prior period tax positions (13.6 ) (37.8 ) (7.7 ) (1.1 ) Reductions related to disposition transactions — (6.6 ) — — Settlements — (2.6 ) (7.8 ) — Lapse of statute of limitations (2.8 ) (2.0 ) (1.7 ) — Balance at end of period $ 182.5 $ 114.8 $ 89.2 $ 118.7
Schedule of Unrecongized Tax Benefits Balance Sheet Location	Unrecognized tax benefits, excluding interest, are reported in the following consolidated balance sheet captions in the amount shown: December 29, 2017 December 30, 2016 Accrued and other current liabilities $ 1.5 $ — Other income tax liabilities 82.6 58.3 Deferred income taxes (non-current liability) 98.4 60.4 $ 182.5 $ 118.7
Schedule of Income Taxes Payable	Income taxes payable, including uncertain tax positions and related interest accruals, is reported in the following consolidated balance sheet captions in the amounts shown: December 29, 2017 December 30, 2016 Income taxes payable $ 15.8 $ 101.7 Other income tax liabilities 94.1 70.4 $ 109.9 $ 172.1
Schedule of Income Tax Receivables and Other Assets	Tax items inherent in other assets decreased from $67.2 million at December 30, 2016 to zero as of December 29, 2017. The $67.2 million decrease was as a result of the early adoption of ASU 2016-16 which moved capitalized tax payments associated with non-current deferred intercompany transactions to retained earnings. Tax items inherent in prepaid expenses and other current assets decreased from $50.3 million at December 30, 2016 to $6.1 million as of December 29, 2017. The $44.2 million decrease was primarily due to the receipt of a $25.4 million U.K. tax credit receivable and a $7.8 million decrease related to the early adoption of ASU 2016-16. Prepaid expenses and other current assets includes $4.2 million and $40.2 million of receivables associated with tax payments on account with the taxing authorities and tax payments of $1.9 million and $10.1 million associated with current deferred intercompany transactions at December 29, 2017 and December 30, 2016, respectively. December 29, 2017 December 30, 2016 Other assets $ — $ 67.2 Prepaid expenses and other current assets 6.1 50.3 $ 6.1 $ 117.5
Schedule of Deferred Taxes Activity	The components of the net deferred tax (liability) asset at the end of each fiscal year were as follows: December 29, 2017 December 30, 2016 Deferred tax assets: Accrued liabilities and reserves $ 62.7 $ 103.3 Inventories 22.3 36.5 Tax loss and credit carryforwards 1,734.5 1,173.7 Environmental liabilities 17.0 28.5 Rebate reserves 1.6 48.0 Expired product 7.5 9.7 Postretirement benefits 14.0 47.5 Federal and state benefit of uncertain tax positions and interest 11.3 17.2 Share-based compensation 23.6 26.1 Intangible assets 575.1 383.2 Other 16.0 — 2,485.6 1,873.7 Deferred tax liabilities: Property, plant and equipment (47.0 ) (110.9 ) Intangible assets (181.0 ) (759.2 ) Interest-bearing deferred tax obligations (553.5 ) (1,801.4 ) Investment in partnership (108.8 ) (173.6 ) Other — (2.0 ) (890.3 ) (2,847.1 ) Net deferred tax asset (liability) before valuation allowances 1,595.3 (973.4 ) Valuation allowances (2,267.9 ) (1,398.3 ) Net deferred tax liability $ (672.6 ) $ (2,371.7 )
Schedule of Deferred Taxes Balance Sheet Location	Deferred taxes are reported in the following consolidated balance sheet captions in the amounts shown: December 29, 2017 December 30, 2016 Other assets $ 16.4 $ 26.4 Deferred income taxes (non-current liability) (689.0 ) (2,398.1 ) Net deferred tax liability $ (672.6 ) $ (2,371.7 )
[1]	Associated unrecognized tax benefit netted within this line.
[2]	During fiscal 2015, the Research Credit tax law was extended, with a retroactive effective date of January 1, 2014. As such, fiscal 2015 includes approximately $3.6 million of credit related to the period January 1, 2014 through September 26, 2014.
[3]	During fiscal 2016, the Company realized a tax benefit of $27.4 million resulting from a U.K. tax credit on a dividend between affiliates.
[4]	During the three months ended December 30, 2016, the rate difference between U.K. and non-U.K. jurisdictions was favorably impacted by a benefit of $16.1 million on a $102.0 million settlement with the Federal Trade Commission and a benefit of $34.5 million on a $207.0 million goodwill impairment in the Specialty Generics segment.
[5]	Includes the impact of certain recurring valuation allowances for U.K. and non-U.K. jurisdictions.
[6]	Reflects redetermination of the Company's deferred tax liabilities as a result of the new U.S. statutory income tax rate of 21% at the date of enactment. Other line items, to the extent U.S. related, are reflected at the former U.S. statutory income tax rate of 35%.
[7]	The statutory tax rate reflects the U.K. statutory tax rate of 19% for fiscal 2017 and 20% for fiscal 2016, 2015 and the three months ended December 30, 2016.

Earnings (Loss) per Share (Tabl

Earnings (Loss) per Share (Tables)	12 Months Ended
	Dec. 29, 2017
Earnings (Loss) per Share [Abstract]
Schedule of Earnings (Loss) per Share	Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Earnings (loss) per share numerator: Income (loss) from continuing operations attributable to common shareholders before allocation of earnings to participating securities $ 1,771.2 $ 489.0 $ 236.6 $ (176.8 ) Less: earnings allocated to participating securities — — 2.0 — Income (loss) from continuing operations attributable to common shareholders, after earnings allocated to participating securities 1,771.2 489.0 234.6 (176.8 ) Income from discontinued operations 363.2 154.7 88.1 23.6 Less: earnings from discontinued operations allocated to participating securities — — 0.7 — Income from discontinued operations attributable to common shareholders, after allocation of earnings to participating securities 363.2 154.7 87.4 23.6 Net income (loss) attributable to common shareholders, after allocation of earnings to participating securities $ 2,134.4 $ 643.7 $ 322.0 $ (153.2 ) Earnings (loss) per share denominator: Weighted-average shares outstanding - basic 97.7 110.6 115.8 105.7 Impact of dilutive securities 0.2 0.9 1.4 — Weighted-average shares outstanding - diluted 97.9 111.5 117.2 105.7 Basic earnings (loss) per share attributable to common shareholders: Income (loss) from continuing operations $ 18.13 $ 4.42 $ 2.03 $ (1.67 ) Income from discontinued operations 3.72 1.40 0.75 0.22 Net income (loss) attributable to common shareholders $ 21.85 $ 5.82 $ 2.78 $ (1.45 ) Diluted earnings (loss) per share attributable to common shareholders: Income (loss) from continuing operations $ 18.09 $ 4.39 $ 2.00 $ (1.67 ) Income from discontinued operations 3.71 1.39 0.75 0.22 Net income (loss) attributable to common shareholders $ 21.80 $ 5.77 $ 2.75 $ (1.45 )

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 29, 2017
Inventory, Net [Abstract]
Schedule of Inventories	Inventories are comprised of the following at the end of each period: December 29, December 30, Raw materials and supplies $ 70.0 $ 72.6 Work in process 167.1 178.4 Finished goods 103.3 99.7 Inventories $ 340.4 $ 350.7

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 29, 2017
Property, Plant and Equipment [Line Items]
Depreciation of Property, Plant and Equipment	Depreciation expense, including amounts related to capitalized leased assets, for continuing operations was as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Depreciation expense $ 113.8 $ 113.3 $ 90.8 $ 27.5
Schedule of Property, Plant and Equipment	The gross carrying amount and accumulated depreciation of property, plant and equipment at the end of each period was as follows: December 29, 2017 December 30, 2016 Land $ 44.0 $ 46.9 Buildings 355.5 291.1 Capitalized software 109.0 87.2 Machinery and equipment 1,123.8 1,052.0 Construction in process 209.7 202.2 1,842.0 1,679.4 Less: accumulated depreciation (875.2 ) (797.9 ) Property, plant and equipment, net $ 966.8 $ 881.5

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 29, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Finite-lived Intangible Assets Amortization Expense	Finite-lived intangible asset amortization expense within continuing operations is as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Amortization expense $ 694.5 $ 700.1 $ 550.3 $ 175.7
Schedule of Goodwill	The changes in the carrying amount of goodwill by segment were as follows: December 29, 2017 December 30, 2016 Gross Carrying amount Accumulated Impairment Gross Carrying amount Accumulated Impairment Specialty Brands $ 3,482.7 $ 0.0 $ 3,498.1 $ 0.0 Specialty Generics 207.0 (207.0 ) 207.0 (207.0 ) Total $ 3,689.7 $ (207.0 ) $ 3,705.1 $ (207.0 )
Schedule of Intangible Assets	The gross carrying amount and accumulated amortization of intangible assets at the end of each period were as follows: December 29, 2017 December 30, 2016 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Amortizable: Completed technology $ 9,882.8 $ 2,260.8 $ 10,028.7 $ 1,617.1 License agreements 177.1 121.1 177.1 112.7 Trademarks 82.1 14.5 82.1 10.9 Customer relationships 29.5 12.2 27.6 8.4 Other 8.6 8.6 6.7 6.7 Total $ 10,180.1 $ 2,417.2 $ 10,322.2 $ 1,755.8 Non-Amortizable: Trademarks $ 35.0 $ 35.0 In-process research and development 577.1 399.1 Total $ 612.1 $ 434.1
Schedule of Future Amortization Expense, Intangible Assets	The estimated aggregate amortization expense on intangible assets owned by the Company is expected to be as follows: Fiscal 2018 $ 681.8 Fiscal 2019 681.4 Fiscal 2020 681.1 Fiscal 2021 680.9 Fiscal 2022 553.9

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 29, 2017
Debt Disclosure [Abstract]
Schedule of Long-term Debt including Capital Lease Obligation	Debt was comprised of the following at the end of each period: December 29, 2017 December 30, 2016 Principal Unamortized Discount and Debt Issuance Costs Principal Unamortized Discount and Debt Issuance Costs Current maturities of long-term debt: Variable-rate receivable securitization due July 2017 $ — $ — $ 250.0 $ 0.3 3.50% notes due April 2018 300.0 0.2 — — Term loans due March 2021 — — 20.0 0.3 4.00% term loan due February 2022 — — 1.0 — Term loan due September 2024 14.0 0.3 — — Capital lease obligation and vendor financing agreements 0.2 — 0.8 — Total current debt 314.2 0.5 271.8 0.6 Long-term debt: 3.50% notes due April 2018 — — 300.0 0.9 4.875% notes due April 2020 700.0 5.7 700.0 8.2 Variable-rate receivable securitization due July 2020 200.0 0.7 — — Term loans due March 2021 — — 1,928.5 33.4 4.00% term loan due February 2022 — — 5.5 — 9.50% debentures due May 2022 10.4 — 10.4 — 5.75% notes due August 2022 884.0 9.5 884.0 11.6 8.00% debentures due March 2023 4.4 — 4.4 — 4.75% notes due April 2023 526.5 4.5 600.0 6.1 5.625% notes due October 2023 738.0 9.7 738.0 11.4 Term loan due September 2024 1,837.2 26.7 — — 5.50% notes due April 2025 692.1 9.0 695.0 10.2 Revolving credit facility 900.0 5.9 100.0 3.2 Total long-term debt 6,492.6 71.7 5,965.8 85.0 Total debt $ 6,806.8 $ 72.2 $ 6,237.6 $ 85.6
Schedule of Maturities of Long-term Debt including Capital Lease Obligation	The aggregate amounts of debt, including the capital lease obligation, maturing during the next five fiscal years are as follows: Fiscal 2018 $ 314.2 Fiscal 2019 18.7 Fiscal 2020 918.7 Fiscal 2021 23.3 Fiscal 2022 1,813.0

Retirement Plans (Tables)

Retirement Plans (Tables)	12 Months Ended
	Dec. 29, 2017
Retirement Benefits [Abstract]
Schedule of Net Periodic Benefit Cost	The net periodic benefit cost (credit) for the Company's pension and postretirement benefit plans was as follows: Pension Benefits Fiscal Year Ended Three Months Ended December 29, September 30, September 25, December 30, Service cost $ 1.4 $ 1.8 $ 2.4 $ 0.8 Interest cost 2.3 13.2 14.5 2.0 Expected return on plan assets (1.3 ) (16.7 ) (18.9 ) (2.3 ) Amortization of net actuarial loss 2.7 11.3 9.2 3.5 Amortization of prior service cost 0.2 — — 0.1 Loss on plan settlements 71.1 8.1 5.9 45.0 Curtailment gain (1.0 ) — — — Net periodic benefit cost $ 75.4 $ 17.7 $ 13.1 $ 49.1 Postretirement Benefits Fiscal Year Ended Three Months Ended December 29, September 30, September 25, December 30, Service cost $ — $ 0.1 $ 0.1 $ 0.1 Interest cost 1.7 2.0 1.9 0.4 Amortization of prior service credit (2.0 ) (2.1 ) (4.0 ) (0.5 ) Gain on plan settlements (0.9 ) — — — Net periodic benefit credit $ (1.2 ) $ — $ (2.0 ) $ —
Schedule of Changes in Benefit Obligations, Plan Assets, and Funded Status of Plans	The following table represents the changes in benefit obligations, plan assets and the net amounts recognized on the consolidated balance sheets for pension and postretirement benefit plans at the end of each period: Pension Benefits Postretirement Benefits December 29, December 30, September 30, December 29, December 30, September 30, Change in benefit obligations: Projected benefit obligations at beginning of year $ 257.4 $ 409.1 $ 375.5 $ 47.5 $ 50.8 $ 52.2 Service cost 1.4 0.8 1.8 — 0.1 0.1 Interest cost 2.3 2.0 13.2 1.7 0.4 2.0 Actuarial (gain) loss (9.0 ) (23.2 ) 65.5 0.2 (2.8 ) 0.5 Benefits and administrative expenses paid (9.4 ) (5.3 ) (20.1 ) (2.9 ) (1.0 ) (4.0 ) Plan settlements (217.0 ) (125.9 ) (26.5 ) (0.9 ) — — Plan curtailments and amendments — — (0.4 ) — — — Net transfer in — 1.1 — — — — Currency translation 2.1 (1.2 ) 0.1 — — — Projected benefit obligations at end of year $ 27.8 $ 257.4 $ 409.1 $ 45.6 $ 47.5 $ 50.8 Change in plan assets: Fair value of plan assets at beginning of year $ 161.0 $ 309.5 $ 309.9 $ — $ — $ — Actual return on plan assets 0.3 (18.1 ) 29.5 — — — Employer contributions 68.0 0.8 16.7 2.9 1.0 4.0 Benefits and administrative expenses paid (9.4 ) (5.3 ) (20.1 ) (2.9 ) (1.0 ) (4.0 ) Plan settlements (217.0 ) (125.9 ) (26.5 ) — — — Net transfer out (2.9 ) — — — — — Fair value of plan assets at end of year $ — $ 161.0 $ 309.5 $ — $ — $ — Funded status at end of year $ (27.8 ) $ (96.4 ) $ (99.6 ) $ (45.6 ) $ (47.5 ) $ (50.8 )
Schedule of Amounts Recognized in Balance Sheet	Pension Benefits Postretirement Benefits December 29, December 30, December 29, December 30, Amounts recognized on the consolidated balance sheet: Non-current assets $ — $ 1.4 $ — $ — Current liabilities (2.4 ) (5.5 ) (3.9 ) (4.2 ) Non-current liabilities (25.4 ) (92.3 ) (41.7 ) (43.3 ) Net amount recognized on the consolidated balance sheet $ (27.8 ) $ (96.4 ) $ (45.6 ) $ (47.5 ) Amounts recognized in accumulated other comprehensive income consist of: Net actuarial loss $ (8.6 ) $ (89.7 ) $ (3.0 ) $ (2.8 ) Prior service (cost) credit (0.5 ) 0.4 10.2 12.3 Net amount recognized in accumulated other comprehensive income $ (9.1 ) $ (89.3 ) $ 7.2 $ 9.5
Schedule of Amounts to be Amortized from Accumulated Other Comprehensive Income	The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost (credit) in fiscal 2018 are as follows: Pension Benefits Postretirement Benefits Amortization of net actuarial loss $ (0.5 ) $ (0.1 ) Amortization of prior service (cost) credit (0.1 ) 2.1
Schedule of Plans with Accumulated Benefit Obligations in Excess of Plan Assets	Additional information related to pension plans is as follows: December 29, December 30, Pension plans with accumulated benefit obligations in excess of plan assets: Accumulated benefit obligation $ 27.3 $ 251.2 Fair value of plan assets — 153.8
Schedule of Actuarial Assumptions	The weighted-average discount rate used to determine net periodic benefit cost and obligations for the Company's postretirement benefit plans are as follows: Fiscal Year Three Months Ended 2017 2016 2015 December 30, 2016 Net periodic benefit cost 3.7 % 4.0 % 3.6 % 3.2 % Benefit obligations 3.4 % 3.2 % 3.9 % 3.8 % Weighted-average assumptions used each period to determine net periodic benefit cost for the Company's pension plans are as follows: U.S. Plans Non-U.S. Plans Fiscal Year Ended Three Months Ended Fiscal Year Ended Three Months Ended 2017 2016 2015 December 30, 2016 2017 2016 2015 December 30, 2016 Discount rate 3.0 % 3.9 % 3.8 % 2.2 % 1.8 % 2.0 % 2.4 % 1.3 % Expected return on plan assets 3.5 % 5.8 % 6.0 % 3.5 % — % 2.0 % 2.0 % — % Rate of compensation increase — % — % — % — % 2.5 % — % — % — % Weighted-average assumptions used each period to determine benefit obligations for the Company's pension plans are as follows: U.S. Plans Non-U.S. Plans Fiscal Year Ended Three Months Ended Fiscal Year Ended Three Months Ended 2017 2016 2015 December 30, 2016 2017 2016 2015 December 30, 2016 Discount rate 3.3 % 2.3 % 3.9 % 3.0 % 1.9 % 1.3 % 2.4 % 1.8 % Rate of compensation increase — % — % — % — % 2.5 % — % — % 0.3 %
Schedule of Healthcare Cost Trend Rates	Healthcare cost trend assumptions for postretirement benefit plans are as follows: December 29, December 30, Healthcare cost trend rate assumed for next fiscal year 6.9 % 6.9 % Rate to which the cost trend rate is assumed to decline 4.5 % 4.5 % Fiscal year the ultimate trend rate is achieved 2038 2038
Schedule of Effect of One-Percentage-Point Change in Assumed Healthcare Cost Trend Rates	A one-percentage-point change in assumed healthcare cost trend rates would have the following effects: One-Percentage-Point Increase One-Percentage-Point Decrease Effect on total of service and interest cost $ — $ — Effect on postretirement benefit obligation 0.2 (0.4 )
Schedule of Weighted Average Allocation of Plan Assets
Schedule of Fair Value of Plan Assets	The following table provides a summary of plan assets held by the Company's pension plans and the respective weighted-average asset allocations as of December 30, 2016 : December 30, 2016 (1) Weighted-Average Asset Allocation Equity Securities: U.S. large cap $ 1.7 1 % Debt securities: Diversified fixed income funds (2) 148.3 92 Cash and cash equivalents 11.0 7 Total $ 161.0 100 % (1) All plan assets were measured at fair value on a recurring basis and were categorized as Level 1 with quoted prices in active markets for identical assets. (2) Diversified fixed income funds consist of U.S. Treasury bonds, mortgage-backed securities, corporate bonds, asset-backed securities and U.S. agency bonds.	[1],[2]
Schedule of Expected Benefit Payments	Benefit payments expected to be paid, reflecting future expected service as appropriate, are as follows: Pension Benefits Postretirement Benefits Fiscal 2018 $ 2.4 $ 3.9 Fiscal 2019 1.8 3.7 Fiscal 2020 1.8 3.5 Fiscal 2021 1.7 3.3 Fiscal 2022 1.6 3.2 Fiscal 2023 - 2027 7.5 14.2
[1]	All plan assets were measured at fair value on a recurring basis and were categorized as Level 1 with quoted prices in active markets for identical assets.
[2]	Diversified fixed income funds consist of U.S. Treasury bonds, mortgage-backed securities, corporate bonds, asset-backed securities and U.S. agency bonds.

Equity (Tables)

Equity (Tables)	12 Months Ended
	Dec. 29, 2017
Equity [Abstract]
Schedule of Share Repurchases under the Repurchase Plan	Share Repurchases On January 23, 2015, the Company's Board of Directors authorized a $300.0 million share repurchase program (the "January 2015 Program"), which was completed during fiscal 2016. On November 19, 2015, the Company's Board of Directors authorized a $500.0 million share repurchase program (the "November 2015 Program"), which was completed in the three months ended December 30, 2016. On March 16, 2016, the Company's Board of Directors authorized an additional $350.0 million share repurchase program (the "March 2016 Program"), which was completed during fiscal 2017. On March 1, 2017, the Company's Board of Directors authorized an additional $1.0 billion share repurchase program (the "March 2017 Program"), which commenced upon the completion of the March 2016 Program. The March 2017 Program has no time limit or expiration date, and the Company currently expects to fully utilize the program. March 2017 Repurchase Program March 2016 November 2015 Repurchase Program January 2015 Repurchase Program Number of Shares Amount Number of Shares Amount Number of Shares Amount Number of Shares Amount Authorized repurchase amount $ 1,000.0 $ 350.0 $ 500.0 $ 300.0 Repurchases: Fiscal 2015 — — — — — — 823,592 75.0 Fiscal 2016 — — — — 6,510,824 425.6 3,199,279 225.0 Three months ended December 30, 2016 — — 1,501,676 84.0 1,063,337 74.4 — — Fiscal 2017 13,490,448 380.6 5,366,741 266.0 — — — — Remaining amount available $ 619.4 $ — $ — $ —

Share Plans (Tables)

Share Plans (Tables)	12 Months Ended
	Dec. 29, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of the Valuation Assumptions Used in the Conversion	The weighted-average assumptions used in the Black-Scholes pricing model for shares granted in fiscal 2017 , 2016 , 2015 and the three months ended December 30, 2016, along with the weighted-average grant-date fair value, were as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Expected share price volatility 36 % 31 % 29 % 35 % Risk-free interest rate 2.00 % 1.74 % 1.72 % 1.23 % Expected annual dividend per share — % — % — % — % Expected life of options (in years) 5.3 5.3 5.3 5.3 Fair value per option $ 18.36 $ 22.82 $ 30.08 $ 20.04
Schedule of Share Option Activity	Share option activity and information is as follows: Share Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding at September 26, 2014 3,526,789 $ 36.84 Granted 635,567 102.20 Exercised (1,132,778 ) 29.79 Expired/Forfeited (243,135 ) 58.00 Outstanding at September 25, 2015 2,786,443 52.76 Granted 1,248,828 72.44 Exercised (413,830 ) 32.76 Expired/Forfeited (199,585 ) 72.65 Outstanding at September 30, 2016 3,421,856 61.17 Granted 3,742 60.01 Exercised (16,382 ) 36.42 Expired/Forfeited (22,522 ) 70.82 Outstanding at December 30, 2016 3,386,694 61.24 Granted 1,719,532 51.57 Exercised (113,605 ) 47.74 Expired/Forfeited (348,637 ) 68.08 Outstanding at December 29, 2017 4,643,984 57.78 6.9 $ 0.2 Vested and non-vested expected to vest as of December 29, 2017 3,882,733 60.62 7.5 $ (0.6 ) Exercisable at December 29, 2017 1,944,709 52.19 4.7 0.2
Share-based Compensation, Performance Shares Award Outstanding Activity	PSU activity is as follows (1) : Shares Weighted-Average Non-vested at September 26, 2014 72,740 $ 63.46 Granted 77,306 125.84 Forfeited (19,072 ) 92.05 Non-vested at September 25, 2015 130,974 96.05 Granted 145,192 83.00 Forfeited (9,521 ) 96.30 Non-vested at September 30, 2016 266,645 88.59 Forfeited (997 ) 154.42 Non-vested at December 30, 2016 265,648 88.51 Granted 348,963 51.73 Forfeited (48,606 ) 107.00 Vested (61,554 ) 62.65 Non-vested at December 29, 2017 504,451 64.44 (1) The number of shares disclosed within this table are at the target number of 100%.
Schedule of Share-based Payment Award, Performance Share Awards, Valuation Assumptions	The assumptions used in the Monte Carlo model for PSUs granted during each year were as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Expected stock price volatility 48 % 41 % 27 % 48 % Peer group stock price volatility 40 % 36 % 32 % 40 % Correlation of returns 17 % 24 % 14 % 17 %
Schedule of Restricted Share Unit Activity	The grant-date fair value of RSAs, adjusted for estimated forfeitures, is recognized as expense on a straight-line basis over the service period. The weighted average grant-date fair value per share is $70.88 . Shares Non-vested at September 26, 2014 1,432,031 Vested (1,362,823 ) Forfeited (34,646 ) Non-vested at September 25, 2015 34,562 Vested (9,760 ) Forfeited (7,936 ) Non-vested at September 30, 2016 16,866 Vested (1,087 ) Forfeited (911 ) Non-vested at December 30, 2016 14,868 Vested (7,970 ) Forfeited (2,223 ) Non-vested at December 29, 2017 4,675 RSU activity is as follows: Shares Weighted-Average Non-vested at September 26, 2014 589,222 $ 47.88 Granted 273,733 105.68 Vested (219,189 ) 49.84 Expired/Forfeited (71,272 ) 68.15 Non-vested at September 25, 2015 572,494 73.45 Granted 615,074 70.10 Vested (193,849 ) 69.27 Expired/Forfeited (99,260 ) 79.95 Non-vested at September 30, 2016 894,459 70.40 Granted 36,731 69.08 Exercised (30,919 ) 47.54 Expired/Forfeited (16,809 ) 49.62 Non-vested at December 30, 2016 883,462 71.03 Granted 655,282 50.74 Exercised (263,189 ) 69.14 Expired/Forfeited (169,789 ) 68.57 Non-vested at December 29, 2017 1,105,766 60.08

Accumulated Other Comprehensi51

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 29, 2017
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income	The components of accumulated other comprehensive income are as follows: Currency Translation Unrecognized Loss on Derivatives Unrecognized Gain (Loss) on Benefit Plans Unrecognized Gain on Equity Securities Accumulated Other Comprehensive Income Balance at September 25, 2015 $ 60.2 $ (6.4 ) $ (52.9 ) $ — $ 0.9 Other comprehensive income (loss), net 0.8 — (39.5 ) — (38.7 ) Reclassification from other comprehensive income (loss) (59.4 ) 0.5 11.1 — (47.8 ) Balance at September 30, 2016 1.6 (5.9 ) (81.3 ) — (85.6 ) Other comprehensive income (loss), net (21.1 ) — 5.3 — (15.8 ) Reclassification from other comprehensive income (loss) — 0.2 28.7 — 28.9 Balance at December 30, 2016 (19.5 ) (5.7 ) (47.3 ) — (72.5 ) Other comprehensive income (loss), net 16.0 — 5.2 1.5 22.7 Reclassification from other comprehensive income (loss) (4.7 ) 1.0 40.6 — 36.9 Balance at December 29, 2017 $ (8.2 ) $ (4.7 ) $ (1.5 ) $ 1.5 $ (12.9 )
Reclassification out of Accumulated Other Comprehensive Income	The following summarizes reclassifications from accumulated other comprehensive income: Amount Reclassified From Accumulated Other Comprehensive Income December 29, 2017 September 30, 2016 December 30, 2016 Line Item in the Consolidated Amortization of unrealized loss on derivatives $ 1.3 $ 0.7 $ 0.2 Interest expense Income tax provision (0.3 ) (0.2 ) — Provision for income taxes Net of income taxes 1.0 0.5 0.2 Amortization of pension and post-retirement benefit plans: Net actuarial loss 2.7 11.4 1.0 (1) Prior service credit (1.9 ) (2.7 ) (0.6 ) (1) Disposal of discontinued operations (3.1 ) 0.8 — Plan settlements 70.2 8.1 45.0 (1) Total before tax 67.9 17.6 45.4 Income tax provision (27.3 ) (6.5 ) (16.7 ) Provision for income taxes Net of income taxes 40.6 11.1 28.7 Currency translation (4.7 ) (59.4 ) — Total reclassifications for the period $ 36.9 $ (47.8 ) $ 28.9 (1) These accumulated other comprehensive income components are included in the computation of net periodic benefit cost. See Note 14 for additional details.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 29, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of Purchase Obligations	At December 29, 2017 , such obligations were as follows: Fiscal 2018 $ 122.6 Fiscal 2019 72.3 Fiscal 2020 60.9 Fiscal 2021 16.1 Fiscal 2022 15.4
Schedule of Minimum Lease Payments for Non-cancelable Leases	The following is a schedule of minimum lease payments for non-cancelable leases as of December 29, 2017 : Operating Leases Capital Leases Fiscal 2018 $ 23.1 $ 0.2 Fiscal 2019 19.2 — Fiscal 2020 17.4 — Fiscal 2021 15.8 — Fiscal 2022 13.8 — Thereafter 61.6 — Total minimum lease payments $ 150.9 $ 0.2

Financial Instruments and Fai53

Financial Instruments and Fair Value Measurements (Tables)	12 Months Ended
	Dec. 29, 2017
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets and Liabilities Measured on a Recurring Basis	The following tables provide a summary of the significant assets and liabilities that are measured at fair value on a recurring basis at the end of each period: December 29, Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Assets: Debt and equity securities held in rabbi trusts $ 35.4 $ 24.0 $ 11.4 $ — Equity securities 22.7 22.7 — — Foreign exchange forward and option contracts 0.1 0.1 — — $ 58.2 $ 46.8 $ 11.4 $ — Liabilities: Deferred compensation liabilities $ 42.7 $ — $ 42.7 $ — Contingent consideration and acquired contingent liabilities 246.4 — — 246.4 Foreign exchange forward and option contracts 0.1 0.1 — — $ 289.2 $ 0.1 $ 42.7 $ 246.4 December 30, Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets: Debt and equity securities held in rabbi trusts $ 33.6 $ 22.8 $ 10.8 $ — Foreign exchange forward and option contracts 0.7 0.7 — — $ 34.3 $ 23.5 $ 10.8 $ — Liabilities: Deferred compensation liabilities $ 32.5 $ — $ 32.5 $ — Contingent consideration and acquired contingent liabilities 250.5 — — 250.5 Foreign exchange forward and option contracts 3.4 3.4 — — $ 286.4 $ 3.4 $ 32.5 $ 250.5
Schedule of Reconciliation of Changes in Fair Value of Contingent Consideration	The following table summarizes the fiscal 2017 activity for contingent considerations: Balance at December 30, 2016 $ 250.5 Acquisition date fair value of contingent consideration 57.0 Payments (25.0 ) Accretion expense 5.3 Fair value adjustment (41.4 ) Balance at December 29, 2017 $ 246.4
Schedule of Carrying Amount and Fair Value of Long-term Debt	The following table presents the carrying values and estimated fair values of the Company's long-term debt, excluding capital leases, as of the end of each period: December 29, 2017 December 30, 2016 Carrying Value Fair Value Carrying Value Fair Value Level 1: Variable-rate receivable securitization due July 2017 $ — $ — $ 250.0 $ 250.0 3.50% notes due April 2018 300.0 299.1 300.0 298.7 4.875% notes due April 2020 700.0 675.2 700.0 699.5 Variable-rate receivable securitization due July 2020 200.0 200.0 — — 5.75% notes due August 2022 884.0 804.8 884.0 850.3 4.75% notes due April 2023 526.5 412.4 600.0 520.9 5.625% notes due October 2023 738.0 628.8 738.0 682.4 5.50% notes due April 2025 692.1 564.5 695.0 615.7 Revolving credit facility 900.0 900.0 100.0 100.0 Level 2: Term loans due March 2021 — — 1,948.5 1,953.2 9.50% debentures due May 2022 10.4 10.9 10.4 12.0 8.00% debentures due March 2023 4.4 4.4 4.4 4.9 Term loan due September 2024 1,851.2 1,848.7 — — Level 3: 4.00% term loan due February 2022 — — 6.5 6.5
Schedules of Concentration of Risk	The following table shows net sales attributable to distributors that accounted for 10% or more of the Company's total net sales: Fiscal Year Ended Three Months Ended December 29, September 30, September 25, December 30, CuraScript, Inc. 40 % 38 % 35 % 43 % McKesson Corporation * 12 % 20 % 10 % AmerisourceBergen Corporation * * 10 % * Cardinal Health, Inc. * * 11 % * * Net sales to these distributors were less than 10% of total net sales during the respective periods presented above. The following table shows accounts receivable attributable to distributors that accounted for 10% or more of the Company's gross accounts receivable at the end of each period: December 29, December 30, McKesson Corporation 26 % 28 % AmerisourceBergen Corporation 15 % 15 % CuraScript, Inc. 14 % 15 % Cardinal Health, Inc. 11 % 10 % The following table shows net sales attributable to products that accounted for 10% or more of the Company's total net sales: Fiscal Year Ended Three Months Ended December 29, September 30, September 25, December 30, H.P. Acthar Gel 37 % 34 % 35 % 39 % Inomax 16 % 14 % 6 % 14 %

Segment and Geographical Data (

Segment and Geographical Data (Tables)	12 Months Ended
	Dec. 29, 2017
Segment Reporting [Abstract]
Schedule of Segment Reporting Information by Business Segment	Selected information by business segment is as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Net sales: Specialty Brands $ 2,325.3 $ 2,300.6 $ 1,622.8 $ 603.1 Specialty Generics 839.5 1,025.2 1,251.6 212.9 Net sales of operating segments (1) 3,164.8 3,325.8 2,874.4 816.0 Other (2) 56.8 55.0 48.7 13.9 Net sales $ 3,221.6 $ 3,380.8 $ 2,923.1 $ 829.9 Operating income: Specialty Brands $ 1,155.2 $ 1,166.2 $ 637.6 $ 317.2 Specialty Generics 231.5 376.1 594.4 52.7 Segment operating income 1,386.7 1,542.3 1,232.0 369.9 Unallocated amounts: Corporate and allocated expenses (3) (172.0 ) (169.8 ) (282.6 ) (181.4 ) Intangible asset amortization (694.5 ) (700.1 ) (550.3 ) (175.7 ) Restructuring and related charges, net (4) (36.4 ) (38.2 ) (45.3 ) (5.3 ) Non-restructuring impairments (63.7 ) (16.9 ) — (214.3 ) Operating income $ 420.1 $ 617.3 $ 353.8 $ (206.8 ) Depreciation and amortization (5) : Specialty Brands $ 708.2 $ 716.6 $ 559.5 $ 178.4 Specialty Generics 100.1 96.8 81.6 24.8 $ 808.3 $ 813.4 $ 641.1 $ 203.2 (1) Amounts represent sales to external customers. There were no intersegment sales. (2) Represents net sales from an ongoing, post-divestiture supply agreement with the acquirer of the CMDS business. Amounts for periods prior to the divestiture represent the reclassification of intercompany sales to third-party sales to conform with the expected presentation of the ongoing supply agreement. (3) Includes administration expenses and certain compensation, environmental and other costs not charged to the Company's operating segments. (4) Includes restructuring-related accelerated depreciation. (5) Depreciation for certain shared facilities is allocated based on occupancy percentage.	[1],[2],[3],[4],[5]
Schedule of Net Sales from External Customers by Products	Net sales by product family within the Company's segments are as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 H.P. Acthar Gel $ 1,195.1 $ 1,160.4 $ 1,037.3 $ 325.4 Inomax 505.2 474.3 185.2 118.3 Ofirmev 302.5 284.3 263.0 72.5 Therakos 214.9 207.6 — 47.4 Hemostasis products 55.1 42.5 — 13.4 Other 52.5 131.5 137.3 26.1 Specialty Brands 2,325.3 2,300.6 1,622.8 603.1 Hydrocodone (API) and hydrocodone-containing tablets 85.3 146.5 167.2 23.2 Oxycodone (API) and oxycodone-containing tablets 78.8 126.2 154.6 24.3 Methylphenidate ER 71.7 103.5 136.5 22.0 Other controlled substances 409.6 468.1 572.2 104.9 Other 194.1 180.9 221.1 38.5 Specialty Generics 839.5 1,025.2 1,251.6 212.9 Other (1) 56.8 55.0 48.7 13.9 Net sales $ 3,221.6 $ 3,380.8 $ 2,923.1 $ 829.9 (1) Represents net sales from an ongoing, post-divestiture supply agreement with the acquirer of the CMDS business. Amounts for periods prior to the divestiture represent the reclassification of intercompany sales to third-party sales to conform with the expected presentation of the ongoing supply agreement.	[6]
Schedule of Net Sales and Long-Lived Assets by Geographical Area	Selected information by geographic area excluding assets held for sale is as follows: Fiscal Year Ended Three Months Ended December 29, 2017 September 30, 2016 September 25, 2015 December 30, 2016 Net sales (1) : U.S. $ 2,899.0 $ 3,095.4 $ 2,647.0 $ 763.7 Europe, Middle East and Africa 242.3 211.8 159.0 52.8 Other 80.3 73.6 117.1 13.4 $ 3,221.6 $ 3,380.8 $ 2,923.1 $ 829.9 Fiscal Year Ended Long-lived assets (2) : December 29, 2017 December 30, 2016 U.S. $ 788.5 $ 759.1 Europe, Middle East and Africa (3) 127.0 82.9 Other 63.5 51.5 $ 979.0 $ 893.5 (1) Net sales are attributed to regions based on the location of the entity that records the transaction, none of which relate to the country of Ireland. (2) Long-lived assets are primarily composed of property, plant and equipment, net. (3) Includes long-lived assets located in Ireland of $126.0 million and $80.9 million as of December 29, 2017 and December 30, 2016, respectively.	[7],[8],[9]
[1]	Amounts represent sales to external customers. There were no intersegment sales.
[2]	Depreciation for certain shared facilities is allocated based on occupancy percentage.
[3]	Includes administration expenses and certain compensation, environmental and other costs not charged to the Company's operating segments.
[4]	Includes restructuring-related accelerated depreciation.
[5]	Represents net sales from an ongoing, post-divestiture supply agreement with the acquirer of the CMDS business. Amounts for periods prior to the divestiture represent the reclassification of intercompany sales to third-party sales to conform with the expected presentation of the ongoing supply agreement.
[6]	Represents net sales from an ongoing, post-divestiture supply agreement with the acquirer of the CMDS business. Amounts for periods prior to the divestiture represent the reclassification of intercompany sales to third-party sales to conform with the expected presentation of the ongoing supply agreement.
[7]	Includes long-lived assets located in Ireland of $126.0 million and $80.9 million
[8]	Long-lived assets are primarily composed of property, plant and equipment, net.
[9]	Net sales are attributed to regions based on the location of the entity that records the transaction, none of which relate to the country of Ireland.

Selected Quarterly Financial 55

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 29, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of Selected Quarterly Financial Data (Unaudited)	For the Quarter Ended March 31, 2017 June 30, 2017 September 29, 2017 December 29, 2017 Net sales $ 810.9 $ 824.5 $ 793.9 $ 792.3 Gross profit 418.6 416.1 400.6 421.0 Income from continuing operations (2) 28.9 70.6 64.3 1,607.4 Income from discontinued operations 370.3 (7.8 ) (0.6 ) 1.3 Net income 399.2 62.8 63.7 1,608.7 Basic earnings per share from continuing operations (1) $ 0.28 $ 0.72 $ 0.66 $ 17.43 Diluted earnings per share from continuing operations (1) 0.28 0.72 0.66 17.40 For the Quarter Ended December 25, 2015 March 25, 2016 June 24, 2016 September 30, 2016 Net sales $ 811.2 $ 815.8 $ 866.6 $ 887.2 Gross profit 450.9 425.1 488.8 490.2 Income from continuing operations 103.8 98.5 176.7 110.0 Income from discontinued operations 107.3 19.8 22.6 5.0 Net income 211.1 118.3 199.3 115.0 Basic earnings per share from continuing operations (1) $ 0.90 $ 0.89 $ 1.63 $ 1.02 Diluted earnings per share from continuing operations (1) 0.89 0.88 1.62 1.01 (1) Quarterly and annual computations are prepared independently. Therefore, the sum of each quarter may not necessarily total the fiscal period amounts noted elsewhere within this Annual Report on Form 10-K. (2) Income from continuing operations for the quarter ended December 29, 2017 reflects one-time effects for the completion of the Reorganization and the impact of U.S. Tax Reform.	[1],[2]
[1]	Income from continuing operations for the quarter ended December 29, 2017 reflects one-time effects for the completion of the Reorganization and the impact of U.S. Tax Reform.
[2]	Quarterly and annual computations are prepared independently. Therefore, the sum of each quarter may not necessarily total the fiscal period amounts noted elsewhere within this Annual Report on Form 10-K.

Condensed Consolidating and C56

Condensed Consolidating and Combining Financial Statements (Tables)	12 Months Ended
	Dec. 29, 2017
Condensed Consolidating Financial Statements [Abstract]
Schedule of Condensed Consolidating Balance Sheets	MALLINCKRODT PLC CONDENSED CONSOLIDATING BALANCE SHEET As of December 29, 2017 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Assets Current Assets: Cash and cash equivalents $ 0.7 $ 908.8 $ 351.4 $ — $ 1,260.9 Accounts receivable, net — — 445.8 — 445.8 Inventories — — 340.4 — 340.4 Deferred income taxes — — — — — Prepaid expenses and other current assets 1.0 0.2 82.9 — 84.1 Notes receivable — — 154.0 — 154.0 Current assets held for sale — — — — Intercompany receivable 70.0 173.4 831.4 (1,074.8 ) — Total current assets 71.7 1,082.4 2,205.9 (1,074.8 ) 2,285.2 Property, plant and equipment, net — — 966.8 — 966.8 Goodwill — — 3,482.7 — 3,482.7 Intangible assets, net — — 8,375.0 — 8,375.0 Long-term assets held for sale — — — — — Investment in subsidiaries 6,551.6 23,217.8 12,356.2 (42,125.6 ) — Intercompany loan receivable 593.1 — 4,664.8 (5,257.9 ) — Other assets — — 171.2 — 171.2 Total Assets $ 7,216.4 $ 24,300.2 $ 32,222.6 $ (48,458.3 ) $ 15,280.9 — Liabilities and Shareholders' Equity Current Liabilities: Current maturities of long-term debt $ — $ 313.5 $ 0.2 $ — $ 313.7 Accounts payable 0.1 — 113.2 — 113.3 Accrued payroll and payroll-related costs — — 98.5 — 98.5 Accrued interest — 53.0 4.0 — 57.0 Income taxes payable — — 15.8 — 15.8 Accrued and other current liabilities 0.8 0.4 450.9 — 452.1 Current liabilities held for sale — — — — — Intercompany payable 693.5 104.6 276.7 (1,074.8 ) — Total current liabilities 694.4 471.5 959.3 (1,074.8 ) 1,050.4 Long-term debt — 6,206.8 214.1 — 6,420.9 Pension and postretirement benefits — — 67.1 — 67.1 Environmental liabilities — — 73.2 — 73.2 Deferred income taxes — — 689.0 — 689.0 Other income tax liabilities — — 94.1 — 94.1 Long-term liabilities held for sale — — — — — Intercompany loans payable — 5,257.9 — (5,257.9 ) — Other liabilities — 7.8 356.4 — 364.2 Total liabilities 694.4 11,944.0 2,453.2 (6,332.7 ) 8,758.9 Shareholders' equity 6,522.0 12,356.2 29,769.4 (42,125.6 ) 6,522.0 Total Liabilities and Shareholders' Equity $ 7,216.4 $ 24,300.2 $ 32,222.6 $ (48,458.3 ) $ 15,280.9 MALLINCKRODT PLC CONDENSED CONSOLIDATING BALANCE SHEET As of December 30, 2016 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Assets Current Assets: Cash and cash equivalents $ 0.5 $ 44.5 $ 297.0 $ — $ 342.0 Accounts receivable, net — — 431.0 — 431.0 Inventories — — 350.7 — 350.7 Deferred income taxes — — — — — Prepaid expenses and other current assets 1.0 — 130.9 — 131.9 Notes receivable — — — — — Current assets held for sale — — 310.9 — 310.9 Intercompany receivable 59.7 65.1 1,081.3 (1,206.1 ) — Total current assets 61.2 109.6 2,601.8 (1,206.1 ) 1,566.5 Property, plant and equipment, net — — 881.5 — 881.5 Goodwill — — 3,498.1 — 3,498.1 Intangible assets, net — — 9,000.5 — 9,000.5 Long-term assets held for sale — — — — — Investment in subsidiaries 5,534.1 20,624.1 10,988.5 (37,146.7 ) — Intercompany loan receivable 3.5 — 3,325.9 (3,329.4 ) — Other assets — — 259.7 — 259.7 Total Assets $ 5,598.8 $ 20,733.7 $ 30,556.0 $ (41,682.2 ) $ 15,206.3 Liabilities and Shareholders' Equity Current Liabilities: Current maturities of long-term debt $ — $ 19.7 $ 251.5 $ — $ 271.2 Accounts payable 0.1 0.1 111.9 — 112.1 Accrued payroll and payroll-related costs — — 76.1 — 76.1 Accrued interest — 53.9 14.8 — 68.7 Income taxes payable — — 101.7 — 101.7 Accrued and other current liabilities 1.9 7.5 547.7 — 557.1 Current liabilities held for sale — — 120.3 — 120.3 Intercompany payable 612.5 467.1 126.5 (1,206.1 ) — Total current liabilities 614.5 548.3 1,350.5 (1,206.1 ) 1,307.2 Long-term debt — 5,860.6 20.2 — 5,880.8 Pension and postretirement benefits — — 136.4 — 136.4 Environmental liabilities — — 73.0 — 73.0 Deferred income taxes — — 2,398.1 — 2,398.1 Other income tax liabilities — — 70.4 — 70.4 Long-term liabilities held for sale — — — — — Intercompany loans payable — 3,329.4 — (3,329.4 ) — Other liabilities — 7.0 349.1 — 356.1 Total liabilities 614.5 9,745.3 4,397.7 (4,535.5 ) 10,222.0 Shareholders' equity 4,984.3 10,988.4 26,158.3 (37,146.7 ) 4,984.3 Total Liabilities and Shareholders' Equity $ 5,598.8 $ 20,733.7 $ 30,556.0 $ (41,682.2 ) $ 15,206.3
Schedule of Condensed Consolidating and Combining Statements of Comprehensive Income	MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME Fiscal year ended December 29, 2017 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Net sales $ — $ — $ 3,221.6 $ — $ 3,221.6 Cost of sales 2.6 — 1,562.7 — 1,565.3 Gross profit (2.6 ) — 1,658.9 — 1,656.3 Selling, general and administrative expenses 59.5 0.7 860.7 — 920.9 Research and development expenses 5.1 — 272.2 — 277.3 Restructuring charges, net — — 31.2 — 31.2 Non-restructuring impairment charges — — 63.7 — 63.7 Separation costs — — — — — Gains on divestiture and license — — (56.9 ) — (56.9 ) Operating income (loss) (67.2 ) (0.7 ) 488.0 — 420.1 Interest expense (13.8 ) (353.9 ) (74.2 ) 72.8 (369.1 ) Interest income 7.3 1.2 68.9 (72.8 ) 4.6 Other income (expense), net 20.3 (1.7 ) (12.6 ) — 6.0 Intercompany interest and fees (18.3 ) — 18.3 — — Equity in net income of subsidiaries 2,200.0 2,901.8 2,549.9 (7,651.7 ) — Income from continuing operations before income taxes 2,128.3 2,546.7 3,038.3 (7,651.7 ) 61.6 Benefit from income taxes (6.1 ) (5.3 ) (1,698.2 ) — (1,709.6 ) Income from continuing operations 2,134.4 2,552.0 4,736.5 (7,651.7 ) 1,771.2 (Loss) income from discontinued operations, net of income taxes — (2.1 ) 365.3 — 363.2 Net income 2,134.4 2,549.9 5,101.8 (7,651.7 ) 2,134.4 Other comprehensive income, net of tax 59.6 59.6 118.2 (177.8 ) 59.6 Comprehensive income $ 2,194.0 $ 2,609.5 $ 5,220.0 $ (7,829.5 ) $ 2,194.0 MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME Fiscal year ended September 30, 2016 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Net sales $ — $ — $ 3,380.8 $ — $ 3,380.8 Cost of sales — — 1,525.8 — 1,525.8 Gross profit — — 1,855.0 — 1,855.0 Selling, general and administrative expenses 51.3 0.8 873.2 — 925.3 Research and development expenses — — 262.2 — 262.2 Restructuring charges, net — — 33.3 — 33.3 Non-restructuring impairments — — 16.9 — 16.9 Separation costs — — — — — Gains on divestiture and license — — — — — Operating (loss) income (51.3 ) (0.8 ) 669.4 — 617.3 — Interest expense (230.3 ) (327.0 ) (82.4 ) 255.1 (384.6 ) Interest income — 0.5 255.9 (255.1 ) 1.3 Other income (expense), net 90.0 1.7 (92.3 ) — (0.6 ) Intercompany interest and fees (16.1 ) — 16.1 — — Equity in net income of subsidiaries 820.8 1,327.2 1,057.9 (3,205.9 ) — Income from continuing operations before income taxes 613.1 1,001.6 1,824.6 (3,205.9 ) 233.4 Benefit from income taxes (30.6 ) (18.1 ) (206.9 ) — (255.6 ) Income from continuing operations 643.7 1,019.7 2,031.5 (3,205.9 ) 489.0 Income from discontinued operations, net of income taxes — 38.2 116.5 — 154.7 Net income 643.7 1,057.9 2,148.0 (3,205.9 ) 643.7 Other comprehensive loss, net of tax (86.5 ) (86.5 ) (173.5 ) 260.0 (86.5 ) Comprehensive income $ 557.2 $ 971.4 $ 1,974.5 $ (2,945.9 ) $ 557.2 MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME Fiscal year ended September 25, 2015 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Net sales $ — $ — $ 2,923.1 $ — $ 2,923.1 Cost of sales — — 1,300.2 — 1,300.2 Gross profit — — 1,622.9 — 1,622.9 Selling, general and administrative expenses 116.3 15.7 891.8 — 1,023.8 Research and development expenses — — 203.3 — 203.3 Restructuring charges, net 9.8 — 35.2 — 45.0 Non-restructuring impairments — — — — — Separation costs — — — — — Gains on divestiture and license — — (3.0 ) — (3.0 ) Operating (loss) income (126.1 ) (15.7 ) 495.6 — 353.8 Interest expense (96.4 ) (230.2 ) (25.2 ) 96.2 (255.6 ) Interest income — 0.1 97.1 (96.2 ) 1.0 Other income (expense), net 216.3 — (208.2 ) — 8.1 Intercompany interest and fees (14.7 ) — 14.7 — — Equity in net income of subsidiaries 330.6 496.3 250.5 (1,077.4 ) — Income from continuing operations before income taxes 309.7 250.5 624.5 (1,077.4 ) 107.3 Benefit from income taxes (15.9 ) — (113.4 ) — (129.3 ) Income from continuing operations 325.6 250.5 737.9 (1,077.4 ) 236.6 (Loss) income from discontinued operations, net of income taxes (0.9 ) — 89.0 — 88.1 Net income 324.7 250.5 826.9 (1,077.4 ) 324.7 Other comprehensive loss, net of tax (64.8 ) (64.8 ) (69.9 ) 134.7 (64.8 ) Comprehensive income $ 259.9 $ 185.7 $ 757.0 $ (942.7 ) $ 259.9 MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME Three months ended December 30, 2016 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Net sales $ — $ — $ 829.9 $ — $ 829.9 Cost of sales — — 384.1 — 384.1 Gross profit — — 445.8 — 445.8 Selling, general and administrative expenses 13.4 0.2 354.7 — 368.3 Research and development expenses — — 66.2 — 66.2 Restructuring charges, net — — 3.8 — 3.8 Non-restructuring impairments — — 214.3 — 214.3 Separation costs — — — — — Gains on divestiture and license — — — — — Operating loss (13.4 ) (0.2 ) (193.2 ) — (206.8 ) Interest expense (2.9 ) (81.1 ) (17.9 ) 10.6 (91.3 ) Interest income — 0.1 11.0 (10.6 ) 0.5 Other income (expense), net 1.8 0.7 (3.4 ) — (0.9 ) Intercompany interest and fees (4.4 ) — 4.4 — — Equity in net income of subsidiaries (136.5 ) 35.2 (44.5 ) 145.8 — Loss from continuing operations before income taxes (155.4 ) (45.3 ) (243.6 ) 145.8 (298.5 ) Benefit from income taxes (2.2 ) (0.3 ) (119.2 ) — (121.7 ) Loss from continuing operations (153.2 ) (45.0 ) (124.4 ) 145.8 (176.8 ) Income from discontinued operations, net of income taxes — 0.4 23.2 — 23.6 Net loss (153.2 ) (44.6 ) (101.2 ) 145.8 (153.2 ) Other comprehensive income, net of tax 13.1 13.1 26.0 (39.1 ) 13.1 Comprehensive loss $ (140.1 ) $ (31.5 ) $ (75.2 ) $ 106.7 $ (140.1 )
Schedule of Condensed Consolidating and Combining Statements of Cash Flows	MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS Fiscal year ended December 29, 2017 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Cash Flows From Operating Activities: Net cash from operating activities $ 1,233.2 $ 1,139.4 $ 2,274.9 $ (3,920.2 ) $ 727.3 Cash Flows From Investing Activities: Capital expenditures — — (186.1 ) — (186.1 ) Acquisitions and intangibles, net of cash acquired — — (76.3 ) — (76.3 ) Proceeds from disposal of discontinued operations, net of cash — — 576.9 — 576.9 Intercompany loan investment (589.5 ) — (1,157.9 ) 1,747.4 — Investment in subsidiary — (1,475.3 ) — 1,475.3 — Proceeds from sale of subsidiary — — — — — Acquisition of subsidiary — — — — — Restricted cash — — — — — Other — — 3.9 — 3.9 Net cash from investing activities (589.5 ) (1,475.3 ) (839.5 ) 3,222.7 318.4 Cash Flows From Financing Activities: Issuance of external debt — 1,400.0 65.0 — 1,465.0 Repayment of external debt and capital leases — (764.5 ) (152.7 ) — (917.2 ) Debt financing costs — (12.7 ) — — (12.7 ) Proceeds from exercise of share options 4.1 — — — 4.1 Intercompany loan borrowings — 1,747.4 — (1,747.4 ) — Intercompany dividends — (1,170.0 ) (2,750.2 ) 3,920.2 — Capital contribution — — 1,475.3 (1,475.3 ) — Repurchase of shares (651.7 ) — — — (651.7 ) Other 4.1 — (21.8 ) — (17.7 ) Net cash from financing activities (643.5 ) 1,200.2 (1,384.4 ) 697.5 (130.2 ) Effect of currency rate changes on cash — — 2.5 — 2.5 Net increase (decrease) in cash, cash equivalents and restricted cash 0.2 864.3 53.5 — 918.0 Cash, cash equivalents and restricted cash at beginning of period 0.5 44.5 316.1 — 361.1 Cash, cash equivalents and restricted cash at end of period $ 0.7 $ 908.8 $ 369.6 $ — $ 1,279.1 Cash and cash equivalents at end of period $ 0.7 $ 908.8 $ 351.4 $ — $ 1,260.9 Restricted cash included in prepaid expenses and other assets at end of period — — — — — Restricted cash included in other long-term assets at end of period — — 18.2 — 18.2 Cash, cash equivalents and restricted cash at end of period $ 0.7 $ 908.8 $ 369.6 $ — $ 1,279.1 MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS Fiscal year ended September 30, 2016 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Cash Flows From Operating Activities: Net cash from operating activities $ 17.9 $ (47.4 ) $ 1,214.1 $ — $ 1,184.6 Cash Flows From Investing Activities: Capital expenditures — — (182.9 ) — (182.9 ) Acquisitions and intangibles, net of cash acquired — — (245.4 ) — (245.4 ) Proceeds from disposal of discontinued operations, net of cash — 234.0 32.7 — 266.7 Intercompany loan investment — (175.2 ) (1,714.5 ) 1,889.7 — Investment in subsidiary — (861.2 ) — 861.2 — Proceeds from sale of subsidiary 3.4 — — (3.4 ) — Acquisition of subsidiary — — (3.4 ) 3.4 — Other — — 6.0 — 6.0 Net cash from investing activities 3.4 (802.4 ) (2,107.5 ) — 2,750.9 (155.6 ) Cash Flows From Financing Activities: Issuance of external debt — — 98.3 — 98.3 Repayment of external debt and capital leases — (549.2 ) (19.4 ) — (568.6 ) Debt financing costs — — (0.1 ) — (0.1 ) Proceeds from exercise of share options 14.0 — — — 14.0 Intercompany loan borrowings 617.8 1,271.9 — (1,889.7 ) — Capital contribution — — 861.2 (861.2 ) — Repurchase of shares (652.9 ) — — — (652.9 ) Other — — (53.0 ) — (53.0 ) Net cash from financing activities (21.1 ) 722.7 — 887.0 (2,750.9 ) (1,162.3 ) Effect of currency rate changes on cash — — 0.3 — 0.3 Net increase (decrease) in cash, cash equivalents and restricted cash 0.2 (127.1 ) (6.1 ) — (133.0 ) Cash, cash equivalents and restricted cash at beginning of period 0.1 152.1 280.4 — 432.6 Cash, cash equivalents and restricted cash at end of period $ 0.3 $ 25.0 $ 274.3 $ — $ 299.6 Cash and cash equivalents at end of period $ 0.3 $ 25.0 $ 255.2 $ — $ 280.5 Restricted cash included in prepaid expenses and other assets at end of period — — 0.1 — 0.1 Restricted cash included in other long-term assets at end of period — — 19.0 — 19.0 Cash, cash equivalents and restricted cash at end of period $ 0.3 $ 25.0 $ 274.3 $ — $ 299.6 MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS Fiscal year ended September 25, 2015 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Cash Flows From Operating Activities: Net cash from operating activities $ 207.0 $ (148.2 ) $ 871.7 $ — $ 930.5 Cash Flows From Investing Activities: Capital expenditures — — (148.0 ) — (148.0 ) Acquisitions and intangibles, net of cash acquired — — (2,154.7 ) — (2,154.7 ) Intercompany loan investment (149.4 ) — (554.2 ) 703.6 — Subsidiary dividend proceeds — — — — — Investment in subsidiary — (3,014.4 ) — 3,014.4 — Other — — 3.0 — 3.0 Net cash from investing activities (149.4 ) (3,014.4 ) (2,853.9 ) — 3,718.0 (2,299.7 ) Cash Flows From Financing Activities: Issuance of external debt — 2,890.0 120.0 — 3,010.0 Repayment of external debt and capital leases — (258.3 ) (1,590.1 ) — (1,848.4 ) Debt financing costs — (39.1 ) (0.8 ) — (39.9 ) Proceeds from exercise of share options 34.4 — — — 34.4 Subsidiary dividend payment — — — — — Intercompany loan borrowings — 703.6 — (703.6 ) — Capital contribution — — 3,014.4 (3,014.4 ) — Repurchase of shares (92.2 ) — — — (92.2 ) Other — — (28.1 ) — (28.1 ) Net cash from financing activities (57.8 ) 3,296.2 — 1,515.4 (3,718.0 ) 1,035.8 Effect of currency rate changes on cash — — (11.6 ) — (11.6 ) Net (decrease) increase in cash, cash equivalents and restricted cash (0.2 ) 133.6 (478.4 ) — (345.0 ) Cash, cash equivalents and restricted cash at beginning of period 0.3 18.5 758.8 — 777.6 Cash, cash equivalents and restricted cash at end of period $ 0.1 $ 152.1 $ 280.4 $ — $ 432.6 Cash and cash equivalents at end of period $ 0.1 $ 152.1 $ 213.7 $ — $ 365.9 Restricted cash included in prepaid expenses and other assets at end of period — — 47.7 — 47.7 Restricted cash included in other long-term assets at end of period — — 19.0 — 19.0 Cash, cash equivalents and restricted cash at end of period $ 0.1 $ 152.1 $ 280.4 $ — $ 432.6 MALLINCKRODT PLC CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS Three months ended December 30, 2016 (in millions) Mallinckrodt plc Mallinckrodt International Finance S.A. Other Subsidiaries Eliminations Consolidated Cash Flows From Operating Activities: Net cash from operating activities $ 17.4 $ (94.0 ) $ 272.2 $ — $ 195.6 Cash Flows From Investing Activities: Capital expenditures — — (65.2 ) — (65.2 ) Acquisitions and intangibles, net of cash acquired — — (1.8 ) — (1.8 ) Intercompany loan investment — — (424.7 ) 424.7 — Subsidiary dividend proceeds — — — — — Investment in subsidiary — (260.0 ) — 260.0 — Other — — (10.2 ) — (10.2 ) Net cash from activities — (260.0 ) (501.9 ) — 684.7 (77.2 ) Cash Flows From Financing Activities: Issuance of external debt — 175.0 15.0 — 190.0 Repayment of external debt and capital leases — (86.2 ) (0.5 ) — (86.7 ) Debt financing costs — — — — — Proceeds from exercise of share options 0.4 — — — 0.4 Subsidiary dividend payment — — — — — Intercompany loan borrowings 140.0 284.7 — (424.7 ) — Capital contribution — — 260.0 (260.0 ) — Repurchase of shares (158.8 ) — — — (158.8 ) Other 1.2 — — — 1.2 Net cash from financing activities (17.2 ) 373.5 — 274.5 (684.7 ) (53.9 ) Effect of currency rate changes on cash — — (3.0 ) — (3.0 ) Net increase in cash, cash equivalents and restricted cash 0.2 19.5 41.8 — 61.5 Cash, cash equivalents and restricted cash at beginning of period 0.3 25.0 274.3 — 299.6 Cash, cash equivalents and restricted cash at end of period $ 0.5 $ 44.5 $ 316.1 $ — $ 361.1 Cash and cash equivalents at end of period $ 0.5 $ 44.5 $ 297.0 $ — $ 342.0 Restricted cash included in prepaid expenses and other assets at end of period — — 0.1 — 0.1 Restricted cash included in other long-term assets at end of period — — 19.0 — 19.0 Cash, cash equivalents and restricted cash at end of period $ 0.5 $ 44.5 $ 316.1 $ — $ 361.1

Background and Basis of Prese57

Background and Basis of Presentation (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 25, 2015	Dec. 29, 2017	Dec. 30, 2016	Sep. 30, 2016
Schedule of Basis of Presentation [Line Items]
Stock outstanding after distribution (in shares)		86,336,232	104,667,545	107,167,693
Ordinary shares, par value (in usd per share)		$ 0.20	$ 0.20	$ 0.20
Operating Expense [Member]
Schedule of Basis of Presentation [Line Items]
Prior Period Reclassification Adjustment	$ 56.4

Transition Period (Details)

Transition Period (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																	12 Months Ended
	Dec. 29, 2017		Sep. 29, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 30, 2016	Sep. 30, 2016		Jun. 24, 2016		Mar. 25, 2016		Dec. 25, 2015		Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Transition Period Income Statement [Abstract]
Net sales	$ 792.3		$ 793.9		$ 824.5		$ 810.9		$ 829.9	$ 887.2		$ 866.6		$ 815.8		$ 811.2		$ 3,221.6	$ 3,380.8	$ 2,923.1
Cost of sales									384.1							360.3		1,565.3	1,525.8	1,300.2
Gross profit	421		400.6		416.1		418.6		445.8	490.2		488.8		425.1		450.9		1,656.3	1,855	1,622.9
Selling, general and administrative expenses									368.3							223.3		920.9	925.3	1,023.8
Research and development expenses									66.2							61.4		277.3	262.2	203.3
Restructuring Charges									3.8							4.1		31.2	33.3	45
Other Asset Impairment Charges									214.3							0		63.7	16.9	0
Operating Income (Loss)									206.8							162.1		(420.1)	(617.3)	(353.8)
Interest expense									(91.3)							(97.8)		(369.1)	(384.6)	(255.6)
Interest income									0.5							0.2		4.6	1.3	1
Other income (expense), net									(0.9)							2		6	(0.6)	8.1
Income (loss) from continuing operations before income taxes									(298.5)							66.5		61.6	233.4	107.3
Benefit from income taxes									(121.7)							(37.3)		(1,709.6)	(255.6)	(129.3)
Income (loss) from continuing operations	1,607.4		64.3		70.6		28.9		(176.8)	110		176.7		98.5		103.8		1,771.2	489	236.6
Income (loss) from discontinued operations, net of income taxes	1.3		(0.6)		(7.8)		370.3		23.6	5		22.6		19.8		107.3		363.2	154.7	88.1
Net income (loss)	$ 1,608.7		$ 63.7		$ 62.8		$ 399.2		$ (153.2)	$ 115		$ 199.3		$ 118.3		$ 211.1		$ 2,134.4	$ 643.7	$ 324.7
Income (Loss) from Continuing Operations, Per Basic Share	$ 17.43	[1]	$ 0.66	[1]	$ 0.72	[1]	$ 0.28	[1]	$ (1.67)	$ 1.02	[1]	$ 1.63	[1]	$ 0.89	[1]	$ 0.90	[1]	$ 18.13	$ 4.42	$ 2.03
Income (Loss) from Discontinued Operations, Per Basic Share									0.22							0.93		3.72	1.40	0.75
Earnings Per Share, Basic									$ (1.45)							$ 1.83		$ 21.85	$ 5.82	$ 2.78
Weighted Average Number of Shares Outstanding, Basic									105.7							115.4		97.7	110.6	115.8
Income (Loss) from Continuing Operations, Per Diluted Share	$ 17.40	[1]	$ 0.66	[1]	$ 0.72	[1]	$ 0.28	[1]	$ (1.67)	$ 1.01	[1]	$ 1.62	[1]	$ 0.88	[1]	$ 0.89	[1]	$ 18.09	$ 4.39	$ 2
Income (Loss) from Discontinued Operations, Per Diluted Share									0.22							0.92		3.71	1.39	0.75
Earnings Per Share, Diluted									$ (1.45)							$ 1.82		$ 21.80	$ 5.77	$ 2.75
Weighted Average Number of Shares Outstanding, Diluted									105.7							116.3		97.9	111.5	117.2
[1]	Quarterly and annual computations are prepared independently. Therefore, the sum of each quarter may not necessarily total the fiscal period amounts noted elsewhere within this Annual Report on Form 10-K.

Transition Period Transition Pe

Transition Period Transition Period Cash Flow (Details) - USD ($) $ in Millions	3 Months Ended									12 Months Ended
	Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jun. 24, 2016	Mar. 25, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014
Transition Period Income Statement [Abstract]
Net income (loss)	$ 1,608.7	$ 63.7	$ 62.8	$ 399.2	$ (153.2)	$ 115	$ 199.3	$ 118.3	$ 211.1	$ 2,134.4	$ 643.7	$ 324.7
Depreciation and amortization					203.2				206	808.3	834.5	672.5
Share-based compensation					11				8.5	59.2	42.9	117
Deferred income taxes					(204.3)				(108.9)	(1,744.1)	(432.9)	(191.6)
Asset Impairment Charges					214.3				0	63.7	16.9	0
Inventory provisions					8.5				1.2	34.1	29.2	0
Gain (Loss) on Disposition of Business					0				(97)	418.1	95.3	0
Other Noncash Income (Expense)					9.2				2.9	21.4	(29.6)	25.5
Increase (Decrease) in Accounts Receivable					(36.5)				68.4	16.2	(31.2)	(0.7)
Increase (Decrease) in Inventories					26.3				(14.5)	23.6	17.3	(61.3)
Accounts payable					5.4				(13)	(25.8)	(9.7)	20.4
Income taxes					0.6				82.3	(34.2)	93.9	30.2
Increase (Decrease) in Other Operating Assets and Liabilities, Net					(109.1)				(35.6)	89	(17.9)	79.2
Net Cash Provided by (Used in) Operating Activities, Continuing Operations					195.6				311.4	727.3	1,184.6	930.5
Capital expenditures					(65.2)				(49)	(186.1)	(182.9)	(148)
Payments to Acquire Businesses, Net of Cash Acquired					1.8				0	76.3	245.4	2,154.7
Proceeds from Divestiture of Businesses, Net of Cash Divested					0				263.7	576.9	266.7	0
Payments for (Proceeds from) Other Investing Activities					10.2				0.7	(3.9)	(6)	(3)
Net cash from investing activities					(77.2)				215.4	318.4	(155.6)	(2,299.7)
Issuance of external debt					190				62	1,465	98.3	3,010
Repayment of external debt and capital leases					(86.7)				(129.6)	(917.2)	(568.6)	(1,848.4)
Debt financing costs					0				(0.1)	(12.7)	(0.1)	(39.9)
Proceeds from exercise of share options					0.4				3.6	4.1	14	34.4
Repurchase of shares					(158.8)				(275.4)	(651.7)	(652.9)	(92.2)
Other					1.2				(30)	(17.7)	(53)	(28.1)
Net cash from financing activities					(53.9)				(369.5)	(130.2)	(1,162.3)	1,035.8
Effect of currency rate changes on cash					(3)				(1.5)	2.5	0.3	(11.6)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect					61.5				155.8	918	(133)	(345)
Cash and cash equivalents	1,260.9				342	280.5			521.9	1,260.9	280.5	365.9
Restricted Cash and Investments, Current	0				0.1	0.1			47.5	0	0.1	47.7
Restricted Cash and Investments, Noncurrent	18.2				19	19			19	18.2	19	19
Cash and Cash Equivalents, Including Restricted Cash	$ 1,279.1				$ 361.1	$ 299.6			$ 588.4	$ 1,279.1	$ 299.6	$ 432.6	$ 777.6

Summary of Significant Accoun60

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Schedule of Significant Accounting Policies [Line Items]
Shipping costs	$ 3.4	$ 13.9	$ 12.4	$ 11.6
Foreign Currency Transaction Gain (Loss), before Tax	9	2.5	(3.6)	31.6
Foreign currency transactions gain (loss), derivative instruments	$ (8.9)	$ (4.1)	$ 0.2	$ (24.8)
Customer relationships
Schedule of Significant Accounting Policies [Line Items]
Finite-lived intangible assets - useful lives		12 years
Minimum | Completed Technology
Schedule of Significant Accounting Policies [Line Items]
Finite-lived intangible assets - useful lives		5 years
Minimum | Licensing Agreements
Schedule of Significant Accounting Policies [Line Items]
Finite-lived intangible assets - useful lives		7 years
Minimum | Trademarks
Schedule of Significant Accounting Policies [Line Items]
Finite-lived intangible assets - useful lives		13 years
Minimum | Buildings
Schedule of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life		10 years
Minimum | Leasehold improvements
Schedule of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life		1 year
Minimum | Capitalized software
Schedule of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life		1 year
Minimum | Machinery and equipment
Schedule of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life		1 year
Maximum | Completed Technology
Schedule of Significant Accounting Policies [Line Items]
Finite-lived intangible assets - useful lives		25 years
Maximum | Licensing Agreements
Schedule of Significant Accounting Policies [Line Items]
Finite-lived intangible assets - useful lives		30 years
Maximum | Trademarks
Schedule of Significant Accounting Policies [Line Items]
Finite-lived intangible assets - useful lives		30 years
Maximum | Buildings
Schedule of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life		45 years
Maximum | Leasehold improvements
Schedule of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life		20 years
Maximum | Capitalized software
Schedule of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life		10 years
Maximum | Machinery and equipment
Schedule of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life		20 years

Recently Issued Accounting St61

Recently Issued Accounting Standards Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		$ (72.1)
Accounting Standards Update 2016-18 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 3.1		$ 47.3
Other Assets | Accounting Standards Update 2016-16 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		(67.2)
Prepaid Expenses and Other Current Assets [Member] | Accounting Standards Update 2016-16 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		(7.8)
Deferred income tax liability (non-current) | Accounting Standards Update 2015-17 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification			$ (122.6)
Retained Earnings | Accounting Standards Update 2016-16 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		$ 75
Retained Earnings | ASU 2016-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Description of Prior-period Information Retrospectively Adjusted		2.9

Discontinued Operations and D62

Discontinued Operations and Divestitures (Income (loss) from Discontinued Operations) (Details) - USD ($)		3 Months Ended									12 Months Ended
		Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jun. 24, 2016	Mar. 25, 2016	Dec. 25, 2015	Dec. 29, 2017		Sep. 30, 2016		Sep. 25, 2015		Jan. 27, 2017	Nov. 27, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of income taxes		$ 1,300,000	$ (600,000)	$ (7,800,000)	$ 370,300,000	$ 23,600,000	$ 5,000,000	$ 22,600,000	$ 19,800,000	$ 107,300,000	$ 363,200,000		$ 154,700,000		$ 88,100,000
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal						0					56,900,000		0		3,000,000
U.K.						0					400,000		300,000		200,000
Discontinued Operation, Tax Effect of Discontinued Operation						15,300,000					5,400,000		43,500,000		47,900,000
Benefit from income taxes						(121,700,000)				$ (37,300,000)	(1,709,600,000)		(255,600,000)		(129,300,000)
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount	[1]					(123,000,000)					(219,900,000)	[2]	(249,300,000)	[2]	(152,900,000)	[2]
Non-U.K.						82,000,000					37,700,000		120,500,000		67,300,000
U.K.						(500,000)					600,000		700,000		(800,000)
International Deferred						203,200,000					1,748,300,000		377,100,000		196,000,000
Contrast Media and Delivery Systems
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration																		$ 270,000,000
U.K.															0
Net sales						0					0		61,000,000		413,800,000
Cost of sales						0					0		46,900,000		306,400,000
Selling, general and administrative						0					0		20,300,000		97,500,000
Restructuring charges, net						0					0		0		300,000
Other						0					0		(1,200,000)		(4,700,000)
(Loss) income from discontinued operations						0					0		(7,400,000)		4,900,000
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax						0					0		95,300,000		0
Discontinued Operation, Tax Effect of Discontinued Operation													(2,100,000)
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax						0					0		87,900,000		4,900,000
Discontinued Operation, Tax Effect of Gain (Loss) from Disposal of Discontinued Operation													(400,000)
(Loss) income from discontinued operations net of tax						0					0		90,400,000		(5,900,000)
Non-U.K.													900,000		14,900,000
International Deferred													3,400,000		4,400,000
Nuclear Imaging
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration																	$ 690,000,000
Disposal Group, Including Discontinued Operation, Upfront Consideration																	574,000,000
Discontinued Operation, Amounts of Material Contingent Liabilities Remaining																	$ 77,000,000
Other Tax Expense (Benefit)						100,000					200,000		900,000		400,000
U.K.													100,000		100,000
Net sales						99,400,000					31,600,000		418,600,000		423,800,000
Cost of sales						44,700,000					15,600,000		216,600,000		193,100,000
Selling, general and administrative						16,400,000					7,800,000		83,700,000		89,600,000
Restructuring charges, net						0					0		2,300,000		(4,600,000)
Disposal Group, Including Discontinued Operation, Other Income											(200,000)
Other						(200,000)							(5,700,000)		(37,700,000)
(Loss) income from discontinued operations						38,100,000					8,400,000		110,300,000		108,000,000
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax						0					362,800,000		0		0
Discontinued Operation, Tax Effect of Discontinued Operation						15,300,000					5,200,000		49,000,000		36,400,000
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax						38,100,000					371,200,000		110,300,000		108,000,000
Discontinued Operation, Tax Effect of Gain (Loss) from Disposal of Discontinued Operation											(900,000)
(Loss) income from discontinued operations net of tax						22,800,000					366,000,000		61,300,000		71,600,000
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount						4,400,000					800,000		11,700,000	[1],[2]	14,300,000	[1],[2]
Increase (Decrease) in Accrued Liabilities						3,300,000					3,300,000		14,400,000
Non-U.K.						15,800,000					200,000		52,500,000		27,800,000
International Deferred						(500,000)					(5,400,000)		(3,600,000)		(8,600,000)
Mallinckrodt Baker
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of income taxes						$ 600,000					$ (600,000)		$ 3,000,000		(100,000)
Tastemaker
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Provision for Loss (Gain) on Disposal, Net of Tax															$ 22,500,000
[1]	Includes the impact of certain recurring valuation allowances for U.K. and non-U.K. jurisdictions.
[2]	During fiscal 2015, the Research Credit tax law was extended, with a retroactive effective date of January 1, 2014. As such, fiscal 2015 includes approximately $3.6 million of credit related to the period January 1, 2014 through September 26, 2014.

Discontinued Operations and D63

Discontinued Operations and Divestitures (Assets and Liabilities Held-for-Sale) (Details) - Nuclear Imaging - Discontinued Operations, Held-for-sale - USD ($) $ in Millions	Dec. 29, 2017	Dec. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts receivable	$ 0	$ 49.6
Inventories	0	20
Property, plant and equipment, net	0	188.7
Other current and non-current assets	0	52.6
Total assets classified as held for sale in the balance sheet	0	310.9
Accounts payable	0	19.7
Other current and non-current liabilities	0	100.6
Total liabilities classified as held for sale in the balance sheet	$ 0	$ 120.3

Discontinued Operations and D64

Discontinued Operations and Divestitures, Significant Cash and Non-Cash Transactions (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Contrast Media and Delivery Systems
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation	$ 0	$ 0	$ 0	$ 15.5
Amortization, Discontinued Operations	0	0	0	2.3
Capital expenditures	0	0	1.6	9.5
Nuclear Imaging
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Depreciation	0	0	20.9	13.1
Capital expenditures	$ 2	$ 0.3	$ 9.7	$ 7.6

Discontinued Operations and D65

Discontinued Operations and Divestitures (Narrative) (Details) - USD ($)		1 Months Ended	3 Months Ended									12 Months Ended
		Dec. 31, 2013	Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jun. 24, 2016	Mar. 25, 2016	Dec. 25, 2015	Dec. 29, 2017		Sep. 30, 2016		Sep. 25, 2015		Sep. 26, 2014	Mar. 17, 2017	Jan. 27, 2017	Nov. 27, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Non-restructuring impairment charges							$ 214,300,000					$ 63,700,000		$ 16,900,000		$ 0
Provision for (benefit from) income taxes							121,700,000				$ 37,300,000	1,709,600,000		255,600,000		129,300,000
Tax (benefit) expense on income (loss) from discontinued operations							15,300,000					5,400,000		43,500,000		47,900,000
Income (loss) from discontinued operations, net of income taxes			$ 1,300,000	$ (600,000)	$ (7,800,000)	$ 370,300,000	23,600,000	$ 5,000,000	$ 22,600,000	$ 19,800,000	$ 107,300,000	363,200,000		154,700,000		88,100,000
Gain on Divestiture							0					56,900,000		0		3,000,000
Non-U.K.							82,000,000					37,700,000		120,500,000		67,300,000
Deferred Foreign Income Tax Expense (Benefit)							(203,200,000)					(1,748,300,000)		(377,100,000)		(196,000,000)
Deferred Income Tax Expense (Benefit)							203,700,000					1,747,700,000		376,400,000		196,800,000
U.K.							0					400,000		300,000		200,000
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal							0					56,900,000		0		3,000,000
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount	[1]						(123,000,000)					(219,900,000)	[2]	(249,300,000)	[2]	(152,900,000)	[2]
Nuclear Imaging
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration																				$ 690,000,000
Disposal Group, Including Discontinued Operation, Upfront Consideration																				574,000,000
Income tax expense (benefit)												4,300,000		49,000,000		36,400,000
Tax (benefit) expense on income (loss) from discontinued operations							15,300,000					5,200,000		49,000,000		36,400,000
Other Tax Expense (Benefit)							100,000					200,000		900,000		400,000
Increase (Decrease) in Accrued Liabilities							3,300,000					3,300,000		14,400,000
Non-U.K.							15,800,000					200,000		52,500,000		27,800,000
Deferred Foreign Income Tax Expense (Benefit)							500,000					5,400,000		3,600,000		8,600,000
U.K.														100,000		100,000
Discontinued Operation, Amounts of Material Contingent Liabilities Remaining																				$ 77,000,000
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax							0					362,800,000		0		0
Discontinued Operation, Tax Effect of Gain (Loss) from Disposal of Discontinued Operation												(900,000)
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount							4,400,000					800,000		11,700,000	[1],[2]	14,300,000	[1],[2]
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax							38,100,000					8,400,000		110,300,000		108,000,000
Contrast Media and Delivery Systems
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration																					$ 270,000,000
Income tax expense (benefit)							0					0		(2,500,000)		10,800,000
Taxes paid or to be paid in connection with disposition																10,000,000
Tax (benefit) expense on income (loss) from discontinued operations														(2,100,000)
Non-U.K.														900,000		14,900,000
Deferred Foreign Income Tax Expense (Benefit)														(3,400,000)		(4,400,000)
U.K.																0
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax							0					0		95,300,000		0
Discontinued Operation, Tax Effect of Gain (Loss) from Disposal of Discontinued Operation														(400,000)
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax							0					0		(7,400,000)		4,900,000
Mallinckrodt Baker
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of income taxes							$ 600,000					(600,000)		$ 3,000,000		(100,000)
Tastemaker
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Provision for Loss (Gain) on Disposal, Net of Tax																$ 22,500,000
Intrathecal Therapy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Not Discontinued Operation, Consideration																			$ 203,000,000
Disposal Group, Not Discontinued Operation, Fixed Consideration																			171,000,000
Disposal Group, Not Discontinued Operation, Contingent Consideration																			32,000,000
Disposal Group, Not Discontinued Operation, Upfront Consideration																			17,000,000
Disposal Group, Not Discontinued Operation, Note Receivable Consideration																			154,000,000
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal, Pre-tax												56,600,000
Disposal Group, Not Discontinued Operation, Other Commitment			$ 6,500,000									6,500,000							$ 7,300,000
Oxymorphone ER
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sale of Productive Assets		$ 4,000,000
Contractually Obligated Future Proceeds from Sale Of Productive Assets		$ 8,000,000
Gain on Divestiture																		$ 11,700,000
Other | Intrathecal Therapy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal												48,700,000
Goodwill [Member] | Intrathecal Therapy [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal												$ 49,800,000
[1]	Includes the impact of certain recurring valuation allowances for U.K. and non-U.K. jurisdictions.
[2]	During fiscal 2015, the Research Credit tax law was extended, with a retroactive effective date of January 1, 2014. As such, fiscal 2015 includes approximately $3.6 million of credit related to the period January 1, 2014 through September 26, 2014.

Acquisitions and License Agre66

Acquisitions and License Agreements (Narrative) (Details) - USD ($) $ in Millions	Dec. 11, 2017	Oct. 02, 2017	Sep. 25, 2017	Aug. 31, 2016	Feb. 01, 2016	Sep. 25, 2015	Apr. 16, 2015	Mar. 30, 2018	Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jun. 24, 2016	Mar. 25, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014	Sep. 27, 2013	Jan. 06, 2017	Aug. 31, 2014
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired													$ 1.8				$ 0	$ 76.3	$ 245.4	$ 2,154.7
Cash used to acquire business				$ 0	$ 0	$ 0	$ 0
Net sales									$ 792.3	$ 793.9	$ 824.5	$ 810.9	829.9	$ 887.2	$ 866.6	$ 815.8	811.2	3,221.6	3,380.8	2,923.1
Non-cash impairment charges													214.3				$ 0	63.7	16.9	0
Ocera [Member]
Business Acquisition [Line Items]
Contingent consideration	$ 22
Business Combination, Consideration Transferred, Other	42.4
Total consideration	64.4
Cash used to acquire business								$ (1.9)
Total Debt	0
Contingent consideration, potential maximum	$ 75
Net sales													0					0	0	0
InfaCare [Member]
Business Acquisition [Line Items]
Contingent consideration			$ 35
Business Combination, Consideration Transferred, Other			80.4
Total consideration			73.1
Cash used to acquire business			0
Total Debt			30
Contingent consideration, potential maximum			345
Business Combination, Cash Paid for Consideration			37.2
Other liabilities (non-current)			$ 43.2
Net sales													0					0	0	0
Stratatech [Member]
Business Acquisition [Line Items]
Contingent consideration				54.9
Business Combination, Consideration Transferred, Other				76
Total consideration				130.9
Total Debt				1
Contingent consideration, potential maximum				$ 121
Hemostasis Products
Business Acquisition [Line Items]
Contingent consideration					52
Business Combination, Consideration Transferred, Other					173.5
Total consideration					225.5
Total Debt					0
Contingent consideration, potential maximum					$ 395
Therakos
Business Acquisition [Line Items]
Contingent consideration						0														0
Business Combination, Consideration Transferred, Other						1,300
Total consideration						1,019.1
Cash used to acquire business						(1,000)
Total Debt						344.8														344.8
Net sales													47.4					214.9	207.6	0
Ikaria
Business Acquisition [Line Items]
Contingent consideration							0
Business Combination, Consideration Transferred, Other							2,300
Total consideration							1,253.6
Cash used to acquire business							(1,200)
Total Debt							1,121
Long Term Debt Assumed							1,100
Net sales													121.4					515.1	491.5	191.9
NeuroproteXeon [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred, Other		$ 10
Business Combination, Contingent Consideration, Potential Payment		$ 25
Mesoblast [Member]
Business Acquisition [Line Items]
Payments to Acquire Marketable Securities																		21.5
Available-for-sale Securities, Current																							$ 19.7
Intangible Assets, Current																							$ 1.8
Questcor Pharmaceuticals, Inc.
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Contingent Liability									111.8				124.7					111.8						$ 195.4
Contingent consideration, potential maximum									$ 140									140
Raplixa [Member]
Business Acquisition [Line Items]
Impairment of Intangible Assets, Finite-lived																		63.7
Bristol-Myers Squibb | Licensing Agreements
Business Acquisition [Line Items]
Contingent payment, maximum additional amount																			25
Royalties paid													14.7					53.9	46.3	43.9
Ofirmev | Cadence Pharmaceuticals, Inc. | Licensing Agreements
Business Acquisition [Line Items]
Milestone Payments																				10
Exalgo | Licensing Agreements
Business Acquisition [Line Items]
Contingent payment, maximum additional amount																				73
Royalties paid													0.2					0.2	0.9	3.2
Milestone Payments																						$ 65
Depomed | Licensing Agreements
Business Acquisition [Line Items]
Contingent payment, maximum additional amount																			64
Milestone Payments																					$ 10	22
Xartemis [Member]
Business Acquisition [Line Items]
Impairment of Intangible Assets, Finite-lived													7.3
Finite-Lived Intangible Assets | Exalgo | Licensing Agreements
Business Acquisition [Line Items]
Milestone Payments																						$ 55
Debentures | Therakos
Business Acquisition [Line Items]
Long term debt						750
Debentures | Ikaria
Business Acquisition [Line Items]
Long term debt							1,400
Revolving Credit Facility | Therakos
Business Acquisition [Line Items]
Borrowings, outstanding						$ 500														500
Revolving Credit Facility | Ikaria
Business Acquisition [Line Items]
Borrowings, outstanding							$ 240
Cost of Sales
Business Acquisition [Line Items]
Amortization Of Inventory Step-Up To Cost Of Sales													$ 3.6					$ 10.1	$ 24.3	$ 44.1

Acquisitions and License Agre67

Acquisitions and License Agreements (Schedule of Fair Value of Identifiable Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 29, 2017	Dec. 11, 2017	Sep. 25, 2017	Dec. 30, 2016	Aug. 31, 2016	Feb. 01, 2016	Sep. 25, 2015	Apr. 16, 2015
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Goodwill (non-tax deductible)	$ 3,482.7			$ 3,498.1
Stratatech [Member]
Business Acquisition [Line Items]
Receivables					$ 1.3
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Cash					0.2
Inventory					0
Goodwill (non-tax deductible)					55.1
Other assets, current and non-current					1.9
Total assets acquired					158.3
Current liabilities					4.3
Other liabilities (non-current)					0
Deferred tax liabilities, net (non-current)	22.1				22.1
Contingent consideration (non-current)					54.9
Total Debt					1
Total liabilities assumed					82.3
Net assets acquired					$ 76
Therakos
Business Acquisition [Line Items]
Receivables							$ 22
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Cash							41.3
Inventory							23.5
Intangible assets							1,170
Goodwill (non-tax deductible)							429.9
Other assets, current and non-current							18.2
Total assets acquired							1,704.9
Current liabilities							24.7
Other liabilities (non-current)							0.6
Deferred tax liabilities, net (non-current)							315.7
Contingent consideration (non-current)							0
Total Debt							344.8
Total liabilities assumed							685.8
Net assets acquired							$ 1,019.1
Ikaria
Business Acquisition [Line Items]
Receivables								$ 73.8
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Cash								77.3
Inventory								26.3
Intangible assets								1,971
Goodwill (non-tax deductible)								795
Other assets, current and non-current								100.5
Total assets acquired								3,043.9
Current liabilities								33
Other liabilities (non-current)								15.8
Deferred tax liabilities, net (non-current)								620.5
Contingent consideration (non-current)								0
Total Debt								1,121
Total liabilities assumed								1,790.3
Net assets acquired								$ 1,253.6
Ocera [Member]
Business Acquisition [Line Items]
Receivables		$ 0
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Cash		1
Inventory		0
Goodwill, Acquired During Period	25.1
Other assets, current and non-current		0.4
Total assets acquired		91
Current liabilities		14.5
Other liabilities (non-current)		0
Deferred tax liabilities, net (non-current)		23.2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Non-Current Contingent Consideration		12.8
Contingent consideration (non-current)		22
Total Debt		0
Total liabilities assumed		50.5
Net assets acquired		$ 40.5
InfaCare [Member]
Business Acquisition [Line Items]
Receivables			$ 0
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Cash			1.3
Inventory			0
Goodwill, Acquired During Period	$ 11.4
Other assets, current and non-current			0.1
Total assets acquired			126.3
Current liabilities			14.5
Other liabilities (non-current)			0
Deferred tax liabilities, net (non-current)			8.7
Contingent consideration (non-current)			35
Total Debt			30
Total liabilities assumed			88.2
Net assets acquired			$ 38.1
Hemostasis Products
Business Acquisition [Line Items]
Receivables						$ 0
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest [Abstract]
Cash						3.3
Inventory						94.6
Intangible assets						132.7
Goodwill (non-tax deductible)						3.3
Other assets, current and non-current						7.9
Total assets acquired						241.8
Current liabilities						3.6
Other liabilities (non-current)						10.6
Deferred tax liabilities, net (non-current)						2.1
Contingent consideration (non-current)						52
Total Debt						0
Total liabilities assumed						68.3
Net assets acquired						$ 173.5

Acquisitions and License Agre68

Acquisitions and License Agreements (Schedule of Reconciliation of Total Consideration) (Details) - USD ($) $ in Millions	Dec. 11, 2017	Sep. 25, 2017	Aug. 31, 2016	Feb. 01, 2016	Sep. 25, 2015	Apr. 16, 2015	Mar. 30, 2018
Business Acquisition [Line Items]
Cash used to acquire business			$ 0	$ 0	$ 0	$ 0
Ocera [Member]
Business Acquisition [Line Items]
Total consideration, net of cash	$ 63.4
Plus: cash assumed in acquisition	1
Total consideration	64.4
Cash used to acquire business							$ 1.9
Business Combination, Consideration Transferred, Other	42.4
Less: non-cash contingent consideration	(22)
Net assets acquired	$ 40.5
InfaCare [Member]
Business Acquisition [Line Items]
Total consideration, net of cash		$ 71.8
Plus: cash assumed in acquisition		1.3
Total consideration		73.1
Cash used to acquire business		0
Business Combination, Consideration Transferred, Other		80.4
Less: non-cash contingent consideration		(35)
Net assets acquired		$ 38.1
Therakos
Business Acquisition [Line Items]
Total consideration, net of cash					977.8
Plus: cash assumed in acquisition					41.3
Total consideration					1,019.1
Cash used to acquire business					1,000
Business Combination, Consideration Transferred, Other					1,300
Less: non-cash contingent consideration					0
Net assets acquired					$ 1,019.1
Ikaria
Business Acquisition [Line Items]
Total consideration, net of cash						1,176.3
Plus: cash assumed in acquisition						77.3
Total consideration						1,253.6
Cash used to acquire business						1,200
Business Combination, Consideration Transferred, Other						2,300
Less: non-cash contingent consideration						0
Net assets acquired						$ 1,253.6
Stratatech [Member]
Business Acquisition [Line Items]
Total consideration, net of cash			130.7
Plus: cash assumed in acquisition			0.2
Total consideration			130.9
Business Combination, Consideration Transferred, Other			76
Less: non-cash contingent consideration			(54.9)
Net assets acquired			$ 76
Hemostasis Products
Business Acquisition [Line Items]
Total consideration, net of cash				222.2
Plus: cash assumed in acquisition				3.3
Total consideration				225.5
Business Combination, Consideration Transferred, Other				173.5
Less: non-cash contingent consideration				(52)
Net assets acquired				$ 173.5

Acquisitions and License Agre69

Acquisitions and License Agreements (Schedule of Intangible Assets Acquired) (Details) - USD ($) $ in Millions	Dec. 11, 2017	Sep. 25, 2017	Aug. 31, 2016	Feb. 01, 2016	Sep. 25, 2015	Apr. 16, 2015
Ocera [Member]
Intangible Assets Acquired as Part of Business Combination [Line Items]
Net assets acquired	$ 40.5
InfaCare [Member]
Intangible Assets Acquired as Part of Business Combination [Line Items]
Net assets acquired		$ 38.1
Hemostasis Products
Intangible Assets Acquired as Part of Business Combination [Line Items]
Net assets acquired				$ 173.5
Therakos
Intangible Assets Acquired as Part of Business Combination [Line Items]
Net assets acquired					$ 1,019.1
Ikaria
Intangible Assets Acquired as Part of Business Combination [Line Items]
Net assets acquired						$ 1,253.6
Ikaria | Completed Technology
Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets acquired, weighted-average useful life						15 years
Indefinite lived intangible assets acquired						$ 1,820
Cash flow discount rate						14.50%
Ikaria | Trademarks
Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets acquired, weighted-average useful life						22 years
Indefinite lived intangible assets acquired						$ 70
Cash flow discount rate						14.50%
Stratatech [Member]
Intangible Assets Acquired as Part of Business Combination [Line Items]
Net assets acquired			$ 76
MNK-6105 [Member] | Ocera [Member]
Intangible Assets Acquired as Part of Business Combination [Line Items]
Indefinite lived intangible assets acquired	$ 64.5
Cash flow discount rate	15.50%
Stannsoporfin [Member] | InfaCare [Member]
Intangible Assets Acquired as Part of Business Combination [Line Items]
Indefinite lived intangible assets acquired		$ 113.5
Cash flow discount rate		13.50%
StrataGraft [Member] | Stratatech [Member] | In-process research and development
Intangible Assets Acquired as Part of Business Combination [Line Items]
Indefinite lived intangible assets acquired			$ 99.8
Cash flow discount rate			16.50%
Raplixa [Member] | Hemostasis Products
Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets acquired, weighted-average useful life				15 years
Indefinite lived intangible assets acquired				$ 73
Cash flow discount rate				17.00%
Therakos | Therakos
Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets acquired, weighted-average useful life					15 years
Indefinite lived intangible assets acquired					$ 1,170
Cash flow discount rate					17.00%
Terlipressin [Member] | Ikaria
Intangible Assets Acquired as Part of Business Combination [Line Items]
Indefinite lived intangible assets acquired						$ 81
Cash flow discount rate						17.00%
Recothrom [Member] | Hemostasis Products
Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets acquired, weighted-average useful life				13 years
Indefinite lived intangible assets acquired				$ 42.7
Cash flow discount rate				16.00%
PreveLeak [Member] | Hemostasis Products
Intangible Assets Acquired as Part of Business Combination [Line Items]
Intangible assets acquired, weighted-average useful life				13 years
Indefinite lived intangible assets acquired				$ 17
Cash flow discount rate				17.00%

Acquisitions and License Agre70

Acquisitions and License Agreements (Schedule of Financial Results and Acquisition Costs of Acquirees) (Details) - USD ($) $ in Millions	3 Months Ended									12 Months Ended
	Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jun. 24, 2016	Mar. 25, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Operating Income [Abstract]
Operating income					$ (206.8)				$ (162.1)	$ 420.1	$ 617.3	$ 353.8
Net Sales [Abstract]
Net sales	$ 792.3	$ 793.9	$ 824.5	$ 810.9	829.9	$ 887.2	$ 866.6	$ 815.8	$ 811.2	3,221.6	3,380.8	2,923.1
Ocera [Member]
Operating Income [Abstract]
Operating income					0					(0.4)	0	0
Net Sales [Abstract]
Net sales					0					0	0	0
Acquisition Related Costs					0					0.9	0	0
NeuroproteXeon [Member]
Net Sales [Abstract]
Acquisition Related Costs					0					0.1	0	0
InfaCare [Member]
Operating Income [Abstract]
Operating income					0					(5.4)	0	0
Net Sales [Abstract]
Net sales					0					0	0	0
Acquisition Related Costs					0					1.2	0	0
Stratatech [Member]
Net Sales [Abstract]
Acquisition Related Costs					0					0	3.7	0
Ikaria
Operating Income [Abstract]
Operating income					51					202.8	201.1	47.1
Net Sales [Abstract]
Net sales					121.4					515.1	491.5	191.9
Acquisition Related Costs					0					0	0.2	30.9
Therakos
Operating Income [Abstract]
Operating income					9.2					27	12.5	0
Net Sales [Abstract]
Net sales					47.4					214.9	207.6	0
Acquisition Related Costs					0					0	0.3	22.5
Hemostasis Products
Net Sales [Abstract]
Acquisition Related Costs					0.1					0	2.7	0
Total Acquisitions
Operating Income [Abstract]
Operating income					60.2					224	213.6	47.1
Net Sales [Abstract]
Net sales					168.8					730	699.1	191.9
Acquisition Related Costs					$ 0.1					$ 2.2	$ 6.9	$ 53.4

Acquisitions and License Agre71

Acquisitions and License Agreements (Schedule of Intangible Asset Amortization by Acquiree) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Schedule of Intangible Asset Amortization by Acquiree [Line Items]
Intangible asset amortization	$ 175.7	$ 694.5	$ 700.1	$ 550.3
Ocera [Member]
Schedule of Intangible Asset Amortization by Acquiree [Line Items]
Intangible asset amortization	0	0	0	0
InfaCare [Member]
Schedule of Intangible Asset Amortization by Acquiree [Line Items]
Intangible asset amortization	0	0	0	0
Therakos
Schedule of Intangible Asset Amortization by Acquiree [Line Items]
Intangible asset amortization	19.5	61.7	78	0
Total Acquisitions
Schedule of Intangible Asset Amortization by Acquiree [Line Items]
Intangible asset amortization	50.6	186.2	202.5	57.1
Ikaria
Schedule of Intangible Asset Amortization by Acquiree [Line Items]
Intangible asset amortization	31.1	124.5	124.5	57.1
Cost of Sales
Schedule of Intangible Asset Amortization by Acquiree [Line Items]
Amortization Of Inventory Step-Up To Cost Of Sales	$ 3.6	$ 10.1	$ 24.3	$ 44.1

Restructuring and Related Cha72

Restructuring and Related Charges (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 25, 2015	Jul. 01, 2016	Sep. 27, 2013
Employee terminations
Restructuring Cost and Reserve [Line Items]
Accelerated share based compensation expense	$ 9.8
2013 Mallinckrodt program | Minimum
Restructuring Cost and Reserve [Line Items]
Mallinckrodt program expected cost range			$ 100
2013 Mallinckrodt program | Maximum
Restructuring Cost and Reserve [Line Items]
Mallinckrodt program expected cost range			$ 125
2016 Mallinckrodt Program | Minimum
Restructuring Cost and Reserve [Line Items]
Mallinckrodt program expected cost range		$ 100
2016 Mallinckrodt Program | Maximum
Restructuring Cost and Reserve [Line Items]
Mallinckrodt program expected cost range		$ 125

Restructuring and Related Cha73

Restructuring and Related Charges (Schedule of Restructuring and Related Charges by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 30, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Restructuring Cost and Reserve [Line Items]
Total restructuring and related charges	$ 5.3		$ 36.4	$ 38.2	$ 45.3
Less: accelerated depreciation	(1.5)		(5.2)	(4.9)	(0.3)
Restructuring charges, net	3.8	$ 4.1	31.2	33.3	45
Specialty Brands [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring and related charges	2.6		25.4	23.3	36.5
Specialty Generics [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring and related charges	0.8		7.7	3.4	4.5
Corporate
Restructuring Cost and Reserve [Line Items]
Total restructuring and related charges	$ 1.9		$ 3.3	$ 11.5	$ 4.3

Restructuring and Related Cha74

Restructuring and Related Charges (Schedule of Net Restructuring and Related Charges) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Restructuring Cost and Reserve [Line Items]
Total restructuring and related charges	$ 5.3	$ 36.4	$ 38.2	$ 45.3
Less: non-cash charges, including impairments and accelerated share based compensation expense	(1.5)	(5.2)	(4.9)	(10.1)
Total charges expected to be settled in cash	3.8	31.2	33.3	35.2
2016 Mallinckrodt Program
Restructuring Cost and Reserve [Line Items]
Total restructuring and related charges	5.2	36.2	8.3	0
2013 Mallinckrodt program
Restructuring Cost and Reserve [Line Items]
Total restructuring and related charges	0	0.7	26.2	12
Acquisition programs
Restructuring Cost and Reserve [Line Items]
Total restructuring and related charges	0.1	0.9	3.7	33.6
Other programs
Restructuring Cost and Reserve [Line Items]
Total restructuring and related charges	$ 0	$ 0	$ 0	$ 0.3

Restructuring and Related Cha75

Restructuring and Related Charges (Schedule of Restructuring Reserves by Type of Cost) (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Continuing Operations
Restructuring Reserve [Roll Forward]
Beginning Balance		$ 18.5	$ 14.8	$ 18	$ 34.9
Charges		3.8	36.7	36	37
Changes in estimate from continuing operations			(5.5)	(2.7)	(1.8)
Cash payments		(7.5)	(30.8)	(33.7)	(44.3)
Reclassifications	[1]		(0.3)	(1.3)	(3)
Currency translation					(0.6)
Ending Balance		14.8	15.5	18.5	18
Discontinued Operations, Held-for-sale
Restructuring Reserve [Roll Forward]
Charges, discontinued operations				2.5	4.7
Changes in estimate, discontinued operations				(0.3)	(8.9)
Acquisition programs | Continuing Operations
Restructuring Reserve [Roll Forward]
Beginning Balance		0.5	0.2	10	7.9
Charges		0.1	0.9	5	25.3
Changes in estimate from continuing operations			0	(1.3)	(1.5)
Cash payments		(0.4)	(0.3)	(13.2)	(21.7)
Reclassifications	[1]		0	0	0
Currency translation					0
Ending Balance		0.2	0.8	0.5	10
Acquisition programs | Discontinued Operations, Held-for-sale
Restructuring Reserve [Roll Forward]
Charges, discontinued operations				0	0
Changes in estimate, discontinued operations				0	0
Other programs | Continuing Operations
Restructuring Reserve [Roll Forward]
Beginning Balance		0	0	0	0.4
Charges		0	0	0	0
Changes in estimate from continuing operations			0	0	(0.3)
Cash payments		0	0	0	(0.1)
Reclassifications	[1]		0	0	0
Currency translation					0
Ending Balance		0	0	0	0
Other programs | Discontinued Operations, Held-for-sale
Restructuring Reserve [Roll Forward]
Charges, discontinued operations				0	0
Changes in estimate, discontinued operations				0	0
2016 Mallinckrodt Program | Continuing Operations
Restructuring Reserve [Roll Forward]
Beginning Balance		6.2	9.5	0	0
Charges		3.7	35.8	6.4	0
Changes in estimate from continuing operations			(4.8)	0	0
Cash payments		(0.4)	(26.1)	(0.2)	0
Reclassifications	[1]		(0.3)	0	0
Currency translation					0
Ending Balance		9.5	14.7	6.2	0
2016 Mallinckrodt Program | Discontinued Operations, Held-for-sale
Restructuring Reserve [Roll Forward]
Charges, discontinued operations				0	0
Changes in estimate, discontinued operations				0	0
2013 Mallinckrodt program | Continuing Operations
Restructuring Reserve [Roll Forward]
Beginning Balance		11.8	5.1	8	26.6
Charges		0	0	24.6	11.7
Changes in estimate from continuing operations			(0.7)	(1.4)	0
Cash payments		(6.7)	(4.4)	(20.3)	(22.5)
Reclassifications	[1]		0	(1.3)	(3)
Currency translation					(0.6)
Ending Balance		$ 5.1	$ 0	11.8	8
2013 Mallinckrodt program | Discontinued Operations, Held-for-sale
Restructuring Reserve [Roll Forward]
Charges, discontinued operations				2.5	4.7
Changes in estimate, discontinued operations				$ (0.3)	$ (8.9)
[1]	Represents the reclassification of pension and other postretirement benefits from restructuring reserves to pension and postretirement obligations.

Restructuring and Related Cha76

Restructuring and Related Charges (Schedule of Restructuring Charges Incurred Cumulative to Date) (Details) $ in Millions	Dec. 29, 2017USD ($)
2013 Mallinckrodt program
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred cumulative to date	$ 124.7
2013 Mallinckrodt program | Specialty Brands [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred cumulative to date	18.8
2013 Mallinckrodt program | Specialty Generics [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred cumulative to date	18.3
2013 Mallinckrodt program | Nuclear Imaging
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred cumulative to date	69.9
2013 Mallinckrodt program | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred cumulative to date	17.7
2016 Mallinckrodt Program
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred cumulative to date	50.6
2016 Mallinckrodt Program | Specialty Brands [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred cumulative to date	32.5
2016 Mallinckrodt Program | Specialty Generics [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred cumulative to date	9.1
2016 Mallinckrodt Program | Nuclear Imaging
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred cumulative to date	0
2016 Mallinckrodt Program | Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred cumulative to date	$ 9

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	Sep. 25, 2017	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015	Dec. 11, 2017	Aug. 31, 2016	Feb. 01, 2016	Apr. 16, 2015
Income Tax Contingency [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		20.00%	19.00%	20.00%	20.00%
Increase (Decrease) Tax Expense (Benefit), Change in Operating Income			$ 23.4	$ 146.3
Increase (Decrease) Foreign Tax Expense (Benefit) Due To Acquisitions				32
Increase (Decrease) Tax Expense (Benefit) Due to Amortization of Intangible Assets				56.8
Increase (Decrease) Tax Benefit, Jurisdiction Rate Difference			29.4	(96.4)
Increase (Decrease) Tax Expense (Benefit), Other				25.1
Deferred income taxes		$ 2,398.1	689
Tax Credit Carryforward Utilization					$ 14.3
Income Taxes Paid, Net		95.6	73.4	165.4	123.8
Increase (Decrease) Deferred Tax Liability Resulting from Divestiture			38.9
Operating Loss Carryforwards					7
Income Tax Holiday, Aggregate Dollar Amount		0	1.8	1	5.1
Decrease in Unrecognized Tax Benefits is Reasonably Possible			38.4
Income Tax Benefit, TCJA, discrete			456.9
Increase (Decrease) Deferred Tax Liability Resulting From Tax Reform, TCJA			444.8
Significant Change in Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued That Would Impact Effective Tax Rate, Estimated Range of Change, Upper Bound			4.9
Unrecognized Tax Benefits, Interest on Income Taxes Accrued		7.1	7.1	7.2	41.7
Unrecognized Tax Benefits that Would Impact Effective Tax Rate		116.9	180.8	113.1	87.4
Unrecognized Tax Benefits, Interest on Income Taxes Expense		0	2.6	4.1	5.7
Tax Credit Carryforward, Amount			24.1
Increase (Decrease) Deferred Tax Liability Resulting From Legal Reorganization			1,122.3
Increase (Decrease) Deferred Tax Liability Resulting From Tax Reform			444.8
Increase (Decrease) Deferred Tax Liability Resulting from Installment Note Payments			(270.6)
Increase (Decrease), Deferred Tax Liability Due to Amortization of Intangible Assets			63.6
Increase (Decrease), Deferred Tax Assets Due to Rebate Reserves			47
Increase (Decrease) Deferred Tax Assets Resulting from Legal Settlements			37.5
Increase (Decrease) Deferred Tax Liability Resulting from Acquisitions			29.7
Increase (Decrease) Deferred Tax Liability Resulting from Pension Activity			29.6
Increase (Decrease) Deferred Tax Liability Resulting from Continuing Operations			9.5
Tax Credit Carryforwards, Not Subject to Expiration			2.4
Increase (Decrease) Tax Expense (Benefit) Due to Divestiture			37.6
Increase (Decrease) Tax Expense (Benefit) Due to U.S. Tax Reform			15.2
Hemostasis Products
Income Tax Contingency [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent								$ 2.1
InfaCare [Member]
Income Tax Contingency [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent	$ 8.7
Deferred Tax Assets, Operating Loss Carryforwards, Foreign	4.7
Increase (Decrease), Deferred Tax Liability, Net	8.7
Increase (Decrease) in Deferred Tax Liability, Intangible Assets	$ 13.8
Ikaria
Income Tax Contingency [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent									$ 620.5
Operating Loss Carryforwards					4.8
Tax Credit Carryforward, Amount					7.2
Stratatech [Member]
Income Tax Contingency [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent			22.1				$ 22.1
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liability, Non-Current, Preliminary							$ 24.3
Ocera [Member]
Income Tax Contingency [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent						$ 23.2
Increase (Decrease) in Deferred Tax Liability, Intangible Assets			23.2
Intrathecal Therapy [Member]
Income Tax Contingency [Line Items]
Increase (Decrease), Deferred Tax Assets, Other			0.5
Increase (Decrease) Deferred Tax Liability Resulting from Divestiture			38.9
Increase (Decrease) Deferred Tax Liability Resulting from Future Consideration			56.4
Deferred Tax Assets, Operating Loss Carryforwards			2.3
Increase (Decrease) in Deferred Tax Liability, Intangible Assets			16.6
Increase (Decrease) Deferred Tax Assets Resulting from Committed Product Developments			$ 2.7
U.S. Federal and State Jursidictions [Member] | Latest Tax Year [Member]
Income Tax Contingency [Line Items]
Tax years that remain subject to examination			2,010
U.S. Federal and State Jursidictions [Member] | Earliest Tax Year [Member]
Income Tax Contingency [Line Items]
Tax years that remain subject to examination			2,009
IRELAND
Income Tax Contingency [Line Items]
Tax years that remain subject to examination			2,013
Non-U.K.
Income Tax Contingency [Line Items]
Tax Credit Carryforward Utilization		2	$ 5.6	9.5
Operating Loss Carry back			27.2
Operating Loss Carryforwards		$ 0.3	57.2	29.2
Deferred Tax Assets, Operating Loss Carryforwards			1,604
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration			1,489.9
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration			114.1
Non-U.K. | Hemostasis Products
Income Tax Contingency [Line Items]
Operating Loss Carryforwards				17.9
Internal Revenue Service (IRS) [Member]
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits, Cash Advance Paid in Connection with Proposed Settlement, Interest Payment					1.5
Unrecognized Tax Benefits, Cash Advance Paid in Connection with Proposed Settlement, Tax Payment					7.4
Unrecognized Tax Benefits, Cash Advance Paid in Connection with Proposed Settlement					$ 8.9
U.K.
Income Tax Contingency [Line Items]
Operating Loss Carryforwards			14.3	$ 1
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration			106.4
Tax Cut and Jobs Act [Member]
Income Tax Contingency [Line Items]
Increase (Decrease) Net Operating Loss			6.2
Retained Earnings [Member] | Accounting Standards Update 2016-16 [Member]
Income Tax Contingency [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets			$ 75
Retained Earnings [Member] | Accounting Standards Update 2016-09 [Member]
Income Tax Contingency [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Description of Prior-period Information Retrospectively Adjusted			2.9
Other Assets [Member] | Accounting Standards Update 2016-16 [Member]
Income Tax Contingency [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets			$ (67.2)
Prepaid Expenses and Other Current Assets [Member] | Accounting Standards Update 2016-16 [Member]
Income Tax Contingency [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets			$ (7.8)

Income Taxes (Schedule of Compo

Income Taxes (Schedule of Components of Income from Continuing Operations Before Income Taxes) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 30, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Operating Loss Carryforwards [Line Items]
U.K.	$ (97.4)		$ (165.9)	$ (275.3)	$ (107.5)
Non-U.K.	(201.1)		227.5	508.7	214.8
Income (loss) from continuing operations before income taxes	$ (298.5)	$ 66.5	$ 61.6	$ 233.4	$ 107.3

Income Taxes (Schedule of Signi

Income Taxes (Schedule of Significant Components of Income Taxes Related to Continuing Operations) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 30, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Current:
U.K.	$ 0		$ 0.4	$ 0.3	$ 0.2
Non-U.K.	82		37.7	120.5	67.3
Current income tax provision	82		38.1	120.8	67.5
Deferred:
U.K.	(0.5)		0.6	0.7	(0.8)
Non-U.K.	(203.2)		(1,748.3)	(377.1)	(196)
Deferred income tax benefit	(203.7)		(1,747.7)	(376.4)	(196.8)
Provision for (benefit from) income taxes	$ (121.7)	$ (37.3)	$ (1,709.6)	$ (255.6)	$ (129.3)

Income Taxes (Schedule of Recon

Income Taxes (Schedule of Reconciliation of Income Taxes at Statutory Rate and Tax Provision) (Details) - USD ($) $ in Millions		3 Months Ended			9 Months Ended	12 Months Ended
		Dec. 30, 2016		Dec. 25, 2015	Sep. 26, 2014	Dec. 29, 2017		Sep. 30, 2016		Sep. 25, 2015
Income Taxes [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		20.00%				19.00%		20.00%		20.00%
Provision (benefit) for income taxes at U.K. statutory income tax rate (1)	[1]	$ (59.7)				$ 11.7		$ 46.6		$ 21.4
Adjustments to reconcile to income tax provision:
Rate difference between non-U.S. and U.S. jurisdictions	[2]	(123)				(219.9)	[3]	(249.3)	[3]	(152.9)	[3]
Litigation Settlement, Expense		102
Valuation allowances, nonrecurring		0				(3.7)		2.1		(2.1)
Adjustments to accrued income tax liabilities and uncertain tax positions		0.9				5.1		(14.9)		(7)
Interest and penalties on accrued income tax liabilities and uncertain tax positions		(0.1)				(0.2)		16.4		(0.3)
Investment in partnership		(12.7)				0		0		0
Credits, principally research		(0.7)	[3],[4]		$ (3.6)	(13.8)	[3],[4]	(33.7)	[3],[4]	(8.1)	[3],[4]
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Amount		75.3				0		0		0
Permanently nondeductible and nontaxable items		1.6				6.4		7.9		14.7
Effective income tax rate reconciliation, pension plan settlement		0				(2.4)		0		0
Effective Income Tax Rate Reconciliation, Disposition of Business, Amount		0				18.2		0		0
Income tax benefit, tax cut and jobs act		0				(456.9)		0		0
Other		(3.3)				0.3		2.1		4.4
Income tax benefit, Legal Reorganization		0				(1,054.8)		0		0
Tax Adjustments, Settlements, and Unusual Provisions								27.4
Tax Benefit Resulting from Legal Settlement	[2]	16.1
Increase (Decrease) Deferred Tax Assets Resulting from Legal Settlements						37.5
Provision for (benefit from) income taxes		(121.7)		$ (37.3)		$ (1,709.6)		$ (255.6)		$ (129.3)
IRELAND
Income Taxes [Line Items]
Tax years that remain subject to examination						2,013
Specialty Generics [Member]
Adjustments to reconcile to income tax provision:
Rate difference between non-U.S. and U.S. jurisdictions	[2]	34.5
Goodwill, Impairment Loss		$ 207
[1]	The statutory tax rate reflects the U.K. statutory tax rate of 19% for fiscal 2017 and 20% for fiscal 2016, 2015 and the three months ended December 30, 2016.
[2]	Includes the impact of certain recurring valuation allowances for U.K. and non-U.K. jurisdictions.
[3]	During fiscal 2015, the Research Credit tax law was extended, with a retroactive effective date of January 1, 2014. As such, fiscal 2015 includes approximately $3.6 million of credit related to the period January 1, 2014 through September 26, 2014.
[4]	During fiscal 2016, the Company realized a tax benefit of $27.4 million resulting from a U.K. tax credit on a dividend between affiliates.

Income Taxes (Schedule of Unrec

Income Taxes (Schedule of Unrecognized Tax Benefit Activity) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Balance at beginning of period	$ 114.8	$ 118.7	$ 89.2	$ 82
Additions related to current year tax positions	5	79.9	63.8	4.5
Additions related to prior period tax positions	0	0.3	10.8	19.9
Reductions related to prior period tax positions	(1.1)	(13.6)	(37.8)	(7.7)
Unrecognized Tax Benefits, Decrease Resulting from disposal of business	0	0	(6.6)	0
Settlements	0	0	(2.6)	(7.8)
Lapse of statute of limitations	0	(2.8)	(2)	(1.7)
Balance at end of period	$ 118.7	$ 182.5	$ 114.8	$ 89.2

Income Taxes (Schedule of Unr82

Income Taxes (Schedule of Unrecognized Tax Benefits Balance Sheet Location) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 29, 2017	Dec. 30, 2016	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits, Interest on Income Taxes Release	$ 2.7
Unrecognized Tax Benefits	182.5	$ 118.7	$ 114.8	$ 89.2	$ 82
Accrued and other current liabilities
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits	1.5	0
Other Income Tax Liabilities
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits	82.6	58.3
Deferred income tax liability (non-current)
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits	98.4	60.4
Liabilities, Total [Member]
Income Tax Contingency [Line Items]
Unrecognized Tax Benefits	$ 182.5	$ 118.7

Income Taxes (Schedule of Incom

Income Taxes (Schedule of Income Taxes Payable) (Details) - USD ($) $ in Millions	Dec. 29, 2017	Dec. 30, 2016
Operating Loss Carryforwards [Line Items]
Other income tax liabilities	$ 94.1	$ 70.4
Total income taxes payable	109.9	172.1
Accrued and Other Current Liabilities
Operating Loss Carryforwards [Line Items]
Income taxes payable	15.8	101.7
Other Income Tax Liabilities
Operating Loss Carryforwards [Line Items]
Other income tax liabilities	$ 94.1	$ 70.4

Income Taxes (Schedule of Inc84

Income Taxes (Schedule of Income Tax Receivables and Other Assets) (Details) - USD ($)	12 Months Ended
	Dec. 29, 2017	Dec. 30, 2016
Income Tax Disclosure [Abstract]
Tax Items within Prepaids and Other Current Assets	$ 6,100,000	$ 50,300,000
Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority	4,200,000	40,200,000
Deferred Tax Asset, Intercompany Transaction, Current	1,900,000	10,100,000
Other assets	0	67,200,000
Prepaid expenses and other current assets	6,100,000	50,300,000
Increase (Decrease) in Prepaid Expense and Other Assets	44,200,000
Foreign Tax Credit Receivable Receipt	25,400,000
Total	6,100,000	117,500,000
Tax items within other assets, non-current	$ 0	$ 67,200,000

Income Taxes (Schedule of Defer

Income Taxes (Schedule of Deferred Taxes Activity) (Details) - USD ($) $ in Millions	Dec. 29, 2017	Dec. 30, 2016
Deferred tax assets:
Accrued liabilities and reserves	$ 62.7	$ 103.3
Inventories	22.3	36.5
Tax loss and credit carryforwards	1,734.5	1,173.7
Environmental liabilities	17	28.5
Rebate reserves	1.6	48
Expired product	7.5	9.7
Postretirement benefits	14	47.5
Federal and state benefit of uncertain tax positions and interest	11.3	17.2
Share-based compensation	23.6	26.1
Other	16	0
Total deferred tax assets, gross	2,485.6	1,873.7
Deferred Tax Assets, Goodwill and Intangible Assets	575.1	383.2
Deferred tax liabilities:
Property, plant and equipment	(47)	(110.9)
Intangible assets	(181)	(759.2)
Interest-bearing deferred tax obligations	(553.5)	(1,801.4)
Investment in partnership	(108.8)	(173.6)
Deferred Tax Liabilities, Other	0	(2)
Total deferred tax liabilities, gross	(890.3)	(2,847.1)
Net deferred tax asset (liability) before valuation allowances	1,595.3	(973.4)
Valuation allowances	(2,267.9)	(1,398.3)
Deferred Tax Liabilities, Net	$ (672.6)	$ (2,371.7)

Income Taxes (Schedule of Def86

Income Taxes (Schedule of Deferred Taxes Balance Sheet Location) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 29, 2017	Dec. 30, 2016
Income Tax Contingency [Line Items]
Other assets	$ 16.4	$ 26.4
Deferred income taxes (non-current liability)	(689)	(2,398.1)
Deferred Tax Liabilities, Net	(672.6)	$ (2,371.7)
Increase (Decrease) Deferred Tax Liability Resulting From Legal Reorganization	(1,122.3)
Increase (Decrease) Deferred Tax Liability Resulting From Tax Reform	(444.8)
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability	270.6
Increase (Decrease), Deferred Tax Liability Due to Amortization of Intangible Assets	(63.6)
Increase (Decrease), Deferred Tax Assets Due to Rebate Reserves	47
Increase (Decrease) Deferred Tax Liability Resulting from Divestiture	38.9
Increase (Decrease) Deferred Tax Assets Resulting from Legal Settlements	37.5
Increase (Decrease) Deferred Tax Liability Resulting from Acquisitions	29.7
Increase (Decrease) Deferred Tax Liability Resulting from Pension Activity	29.6
Increase (Decrease) Deferred Tax Liability Resulting from Continuing Operations	$ 9.5

Income Taxes Tax Year Examinati

Income Taxes Tax Year Examination (Details) - U.S. Federal and State Jursidictions [Member]	12 Months Ended
	Dec. 29, 2017
Latest Tax Year [Member]
Income Tax Examination [Line Items]
Tax years that remain subject to examination	2,010
Earliest Tax Year [Member]
Income Tax Examination [Line Items]
Tax years that remain subject to examination	2,009

Earnings (Loss) per Share (Deta

Earnings (Loss) per Share (Details) - shares shares in Millions	3 Months Ended		12 Months Ended
	Dec. 30, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Earnings (Loss) per Share [Abstract]
Weighted-average shares for basic earnings (loss) per share (in shares)	105.7	115.4	97.7	110.6	115.8
Weighted Average Number of Shares Outstanding, Diluted	0		0.2	0.9	1.4
Weighted-average shares for diluted earnings (loss) per share (in shares)	105.7	116.3	97.9	111.5	117.2
Antidilutive securities excluded from weighted-average shares (in shares)	2.4		4.2	1.7	0.1

Earnings (Loss) per Share Sched

Earnings (Loss) per Share Schedule of Earnings per Share Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																	12 Months Ended
	Dec. 29, 2017		Sep. 29, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 30, 2016	Sep. 30, 2016		Jun. 24, 2016		Mar. 25, 2016		Dec. 25, 2015		Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Earnings Per Share [Abstract]
Income (loss) from continuing operations	$ 1,607.4		$ 64.3		$ 70.6		$ 28.9		$ (176.8)	$ 110		$ 176.7		$ 98.5		$ 103.8		$ 1,771.2	$ 489	$ 236.6
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic									0									0	0	2
Income (Loss) From Continuing Operations Attributable To Common Stockholders									(176.8)									1,771.2	489	234.6
Income (loss) from discontinued operations, net of income taxes	$ 1.3		$ (0.6)		$ (7.8)		$ 370.3		23.6	$ 5		$ 22.6		$ 19.8		$ 107.3		363.2	154.7	88.1
Income (Loss) From Discontinued Operations Attributable To Common Stockholders									0									0	0	0.7
Net Income (Loss) Available to Common Stockholders, Basic									23.6									363.2	154.7	87.4
Net Income (Loss) Available to Common Stockholders, Basic									$ (153.2)									$ 2,134.4	$ 643.7	$ 322
Weighted Average Number of Shares Outstanding, Basic									105.7							115.4		97.7	110.6	115.8
Weighted Average Number of Shares Outstanding, Diluted									0									0.2	0.9	1.4
Weighted Average Number of Shares Outstanding, Diluted									105.7							116.3		97.9	111.5	117.2
Income (Loss) from Continuing Operations, Per Basic Share	$ 17.43	[1]	$ 0.66	[1]	$ 0.72	[1]	$ 0.28	[1]	$ (1.67)	$ 1.02	[1]	$ 1.63	[1]	$ 0.89	[1]	$ 0.90	[1]	$ 18.13	$ 4.42	$ 2.03
Income (Loss) from Discontinued Operations, Per Basic Share									0.22							0.93		3.72	1.40	0.75
Earnings Per Share, Basic									(1.45)							1.83		21.85	5.82	2.78
Income (Loss) from Continuing Operations, Per Diluted Share	$ 17.40	[1]	$ 0.66	[1]	$ 0.72	[1]	$ 0.28	[1]	(1.67)	$ 1.01	[1]	$ 1.62	[1]	$ 0.88	[1]	0.89	[1]	18.09	4.39	2
Income (Loss) from Discontinued Operations, Per Diluted Share									0.22							0.92		3.71	1.39	0.75
Earnings Per Share, Diluted									$ (1.45)							$ 1.82		$ 21.80	$ 5.77	$ 2.75
[1]	Quarterly and annual computations are prepared independently. Therefore, the sum of each quarter may not necessarily total the fiscal period amounts noted elsewhere within this Annual Report on Form 10-K.

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	Dec. 29, 2017	Dec. 30, 2016
Inventory, Net [Abstract]
Raw materials and supplies	$ 70	$ 72.6
Work in process	167.1	178.4
Finished goods	103.3	99.7
Inventories	$ 340.4	$ 350.7

Property, Plant and Equipment91

Property, Plant and Equipment (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,679.4	$ 1,842
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	797.9	875.2
Depreciation	$ 27.5	$ 113.8	$ 113.3	$ 90.8

Property, Plant and Equipment92

Property, Plant and Equipment (Schedule of Property, Plant and Equipment) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Property, Plant and Equipment [Line Items]
Depreciation	$ 27.5	$ 113.8	$ 113.3	$ 90.8
Property, plant and equipment, gross	1,679.4	1,842
Less: accumulated depreciation	(797.9)	(875.2)
Property, plant and equipment, net	881.5	966.8
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	46.9	44
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	291.1	355.5
Capitalized Software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	87.2	109
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,052	1,123.8
Construction in Progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 202.2	$ 209.7

Goodwill and Intangible Asset93

Goodwill and Intangible Assets Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 30, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible asset amortization	$ 175.7		$ 694.5	$ 700.1	$ 550.3
Finite-Lived Intangible Assets [Line Items]
Goodwill, Period Increase (Decrease)			(15.4)
Other Asset Impairment Charges	214.3	$ 0	63.7	$ 16.9	$ 0
Goodwill, Impaired, Accumulated Impairment Loss	207		207
Goodwill	$ 3,498.1		3,482.7
Intrathecal Therapy [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill, Written off Related to Sale of Business Unit			$ 49.8
Brands
Finite-Lived Intangible Assets [Line Items]
Weighted Average Cost of Capital, Rate			12.50%
Specialty Generics [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Cost of Capital, Rate	9.50%
Goodwill, Impaired, Accumulated Impairment Loss	$ (207)		$ (207)
Goodwill, Impairment Loss	$ 207
Raplixa [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived			$ 63.7

Goodwill and Intangible Asset94

Goodwill and Intangible Assets (Schedule Of Goodwill) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 29, 2017	Dec. 30, 2016	Aug. 31, 2016	Sep. 25, 2015	Apr. 16, 2015
Goodwill [Line Items]
Goodwill, Period Increase (Decrease)	$ (15.4)
Goodwill	3,482.7	$ 3,498.1
Goodwill, Gross	3,689.7	3,705.1
Goodwill, Impaired, Accumulated Impairment Loss	(207)	(207)
Specialty Brands [Member]
Goodwill [Line Items]
Goodwill	3,482.7
Goodwill, Gross		3,498.1
Goodwill, Impaired, Accumulated Impairment Loss	0	0
Specialty Generics [Member]
Goodwill [Line Items]
Goodwill, Gross	207	207
Goodwill, Impaired, Accumulated Impairment Loss	$ 207	$ 207
Stratatech [Member]
Goodwill [Line Items]
Goodwill			$ 55.1
Ikaria
Goodwill [Line Items]
Goodwill					$ 795
Therakos
Goodwill [Line Items]
Goodwill				$ 429.9

Goodwill and Intangible Asset95

Goodwill and Intangible Assets (Schedule Of Intangible Assets) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Schedule of Intangible Asset by Major Class [Line Items]
Intangible asset amortization	$ 175.7	$ 694.5	$ 700.1	$ 550.3
Amortizable:
Finite-lived intangible assets, gross	10,322.2	10,180.1
Accumulated amortization	1,755.8	2,417.2
Non-Amortizable:
Indefinite-lived intangible assets, gross	434.1	612.1
Trademarks
Non-Amortizable:
Indefinite-lived intangible assets, gross	35	35
In-process research and development
Non-Amortizable:
Indefinite-lived intangible assets, gross	399.1	577.1
Completed Technology
Amortizable:
Finite-lived intangible assets, gross	10,028.7	9,882.8
Accumulated amortization	1,617.1	2,260.8
Licensing Agreements
Amortizable:
Finite-lived intangible assets, gross	177.1	177.1
Accumulated amortization	112.7	121.1
Customer relationships
Amortizable:
Finite-lived intangible assets, gross	27.6	29.5
Accumulated amortization	8.4	12.2
Trademarks
Amortizable:
Finite-lived intangible assets, gross	82.1	82.1
Accumulated amortization	10.9	14.5
Other
Amortizable:
Finite-lived intangible assets, gross	6.7	8.6
Accumulated amortization	$ 6.7	$ 8.6

Goodwill and Intangible Asset96

Goodwill and Intangible Assets (Schedule of Future Amortization Expense, Intangible Assets) (Details) $ in Millions	Dec. 29, 2017USD ($)
Finite-Lived Intangible Assets [Line Items]
Fiscal 2,018	$ 681.8
Fiscal 2,019	681.4
Fiscal 2,020	681.1
Fiscal 2,021	680.9
Fiscal 2,022	$ 553.9

Debt (Narrative) (Details)

Debt (Narrative) (Details) - USD ($)	Feb. 21, 2018	Jul. 28, 2017	Feb. 28, 2017	Sep. 24, 2015	Apr. 15, 2015	Dec. 29, 2017	Sep. 25, 2015	Dec. 30, 2016	Aug. 31, 2014	Apr. 30, 2013
Debt Instrument [Line Items]
Long-term Debt, Gross						$ 6,492,600,000		$ 5,965,800,000
Term loan due March 2021
Debt Instrument [Line Items]
Loans Payable						$ 0		1,948,500,000
2017 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Repayments of Debt	$ 275,000,000
Long-term Debt, Gross	$ 625,000,000
Term Loan due Sept 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage						4.00%
Long-term Debt, Gross						$ 1,851,200,000
2023 Notes
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage				100.00%
Prior To April 15, 2018 | 2025 Notes
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage					40.00%
Debentures | 5.625% notes due October 2023
Debt Instrument [Line Items]
Long-term Debt, Gross						$ 738,000,000		738,000,000
Debentures | 2017 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 900,000,000
Line of Credit Facility, Interest Rate at Period End						3.94%
Variable interest rate			2.25%
Long-term Debt, Gross						$ 900,000,000
Debentures | 2015 Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 500,000,000
Long-term Debt, Gross						900,000,000		100,000,000
Debentures | 2020 Notes
Debt Instrument [Line Items]
Debt instrument, face amount					$ 700,000,000
Stated interest rate					4.875%
Debentures | 2023 Notes
Debt Instrument [Line Items]
Debt instrument, face amount				$ 750,000,000
Stated interest rate				5.625%
Debentures | 2025 Notes
Debt Instrument [Line Items]
Debt instrument, face amount					$ 700,000,000
Stated interest rate					5.50%
Prior To April 15, 2017 | 2023 Notes
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage				40.00%
Line of Credit
Debt Instrument [Line Items]
Borrowings, outstanding							$ 0
Senior Notes | 3.50% notes due April 2018
Debt Instrument [Line Items]
Debt instrument, face amount										$ 300,000,000
Stated interest rate										3.50%
Long-term Debt, Gross						0		300,000,000
Senior Notes | 4.75% notes due April 2023
Debt Instrument [Line Items]
Debt instrument, face amount										$ 600,000,000
Stated interest rate										4.75%
Long-term Debt, Gross						526,500,000		600,000,000
Senior Notes | 5.75% notes due August 2022
Debt Instrument [Line Items]
Debt instrument, face amount									$ 900,000,000
Stated interest rate									5.75%
Long-term Debt, Gross						884,000,000		884,000,000
Secured Debt | Term loan due March 2021
Debt Instrument [Line Items]
Long-term Debt, Gross						$ 0		1,928,500,000
Secured Debt | Variable Rate Receivable Securitization 2020 [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate at Period End						2.46%
Variable rate receivable securitization						$ 200,000,000
Secured Debt | Term Loan due Sept 2024 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross						1,837,200,000		0
Secured Debt | New Term Loan
Debt Instrument [Line Items]
Loans Payable						1,851,200,000		0
Secured Debt | Term Loan and New Term Loan
Debt Instrument [Line Items]
Repayments of Debt						83,500,000
Write off of Deferred Debt Issuance Cost						10,000,000
Variable interest rate			2.75%
Quarterly amortization payments			0.25%
Long-term Debt, Gross			$ 1,865,000,000
Secured Debt | Receivable securitization, Maturity Date of July 2020 [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 250,000,000
Line Of Credit Facility, Future Contingent Maximum Borrowing Capacity		$ 300,000,000
Facility fees for letters of credit		0.40%
Variable interest rate		0.90%
Variable rate receivable securitization								0
Long-term Debt, Gross						$ 200,000,000		0
2017 Revolving Credit Facility [Member] | Term loan due March 2021
Debt Instrument [Line Items]
Facility fees for letters of credit						0.275%
Prior to August 1, 2017 | 5.75% notes due August 2022
Debt Instrument [Line Items]
Debt Instrument, Redemption Price, Percentage							40.00%
Option A | 5.75% notes due August 2022
Debt Instrument [Line Items]
Repurchase percentage							101.00%
Option A | 2023 Notes
Debt Instrument [Line Items]
Repurchase percentage				101.00%
Option A | 2025 Notes
Debt Instrument [Line Items]
Repurchase percentage					101.00%
Option B | 5.75% notes due August 2022
Debt Instrument [Line Items]
Repurchase percentage							100.00%
Option B | 2023 Notes
Debt Instrument [Line Items]
Repurchase percentage				100.00%
Option B | 2025 Notes
Debt Instrument [Line Items]
Repurchase percentage					100.00%
Letter of Credit | 2017 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity			$ 50,000,000
Letter of Credit | 2015 Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity								$ 150,000,000

Debt (Schedule of Long term deb

Debt (Schedule of Long term debt and Capital lease obligation) (Details) - USD ($) $ in Millions	Feb. 21, 2018	Dec. 29, 2017	Dec. 30, 2016
Current maturities of long-term debt:
Long-term Debt, Current Maturities		$ 314.2	$ 271.8
Debt Issuance Costs, Current, Net		0.5	0.6
Capital lease obligation and vendor financing agreements		0.2	0.8
Long-term debt:
Long-term Debt, Gross		6,492.6	5,965.8
Debt, Long-term and Short-term, Combined Amount		6,806.8	6,237.6
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net		72.2	85.6
Variable rate receivable securitization
Current maturities of long-term debt:
Long-term Debt, Current Maturities		0	250
Debt Issuance Costs, Current, Net		0	0.3
Capital Lease Obligations [Member]
Current maturities of long-term debt:
Debt Issuance Costs, Current, Net		0	0
2017 Revolving Credit Facility [Member]
Long-term debt:
Long-term Debt, Gross	$ 625
Term Loan due Sept 2024 [Member]
Long-term debt:
Long-term Debt, Gross		1,851.2
Long-term Debt [Member]
Long-term debt:
Debt Issuance Costs, Net		71.7	85
Senior Notes | 3.50% notes due April 2018
Current maturities of long-term debt:
Long-term Debt, Current Maturities		300	0
Debt Issuance Costs, Current, Net		0.2	0
Long-term debt:
Long-term Debt, Gross		0	300
Debt Issuance Costs, Net		0	0.9
Senior Notes | 4.75% notes due April 2023
Long-term debt:
Long-term Debt, Gross		526.5	600
Debt Issuance Costs, Net		4.5	6.1
Senior Notes | 5.75% notes due August 2022
Long-term debt:
Long-term Debt, Gross		884	884
Debt Issuance Costs, Net		9.5	11.6
Debentures | Four Point Eight Eight Percent Notes [Member]
Long-term debt:
Long-term Debt, Gross		700	700
Debt Issuance Costs, Net		5.7	8.2
Debentures | 5.625% notes due October 2023
Long-term debt:
Long-term Debt, Gross		738	738
Debt Issuance Costs, Net		9.7	11.4
Debentures | Five Point Five Percent Notes [Member]
Long-term debt:
Long-term Debt, Gross		692.1	695
Debt Issuance Costs, Net		9	10.2
Debentures | 2015 Revolving Credit Facility
Long-term debt:
Long-term Debt, Gross		900	100
Debt Issuance Costs, Net			3.2
Debentures | 2017 Revolving Credit Facility [Member]
Long-term debt:
Long-term Debt, Gross		900
Debt Issuance Costs, Net		5.9
Secured Debt | Term loan due March 2021
Current maturities of long-term debt:
Long-term Debt, Current Maturities		0	20
Debt Issuance Costs, Current, Net		0	0.3
Long-term debt:
Long-term Debt, Gross		0	1,928.5
Debt Issuance Costs, Net		0	33.4
Secured Debt | Receivable securitization, Maturity Date of July 2020 [Member]
Current maturities of long-term debt:
Variable rate receivable securitization			0
Long-term debt:
Long-term Debt, Gross		200	0
Debt Issuance Costs, Net		0.7	0
Secured Debt | 4.00% term loan due February 2022
Current maturities of long-term debt:
Long-term Debt, Current Maturities		0	1
Debt Issuance Costs, Current, Net		0	0
Long-term debt:
Long-term Debt, Gross		0	5.5
Debt Issuance Costs, Net		0	0
Secured Debt | Variable rate receivable securitization
Current maturities of long-term debt:
Variable rate receivable securitization		0
Secured Debt | Term Loan due Sept 2024 [Member]
Current maturities of long-term debt:
Long-term Debt, Current Maturities		14	0
Debt Issuance Costs, Current, Net		0.3	0
Long-term debt:
Long-term Debt, Gross		1,837.2	0
Debt Issuance Costs, Noncurrent, Net		26.7	0
Debentures | 8.00% debentures due March 2023
Long-term debt:
Long-term Debt, Gross		4.4	4.4
Debt Issuance Costs, Net		0	0
Debentures | 9.50% debentures due May 2022
Long-term debt:
Long-term Debt, Gross		10.4	10.4
Debt Issuance Costs, Net		$ 0	$ 0

Debt (Schedule of Maturities of

Debt (Schedule of Maturities of Long-term Debt including Capital Lease Obligation) (Details) $ in Millions	Dec. 29, 2017USD ($)
Debt Disclosure [Abstract]
Fiscal 2,018	$ 314.2
Fiscal 2,019	18.7
Fiscal 2,020	918.7
Fiscal 2,021	23.3
Fiscal 2,022	$ 1,813

Retirement Plans Narrative (Det

Retirement Plans Narrative (Details) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016USD ($)	Dec. 29, 2017USD ($)contract	Sep. 30, 2016USD ($)	Sep. 25, 2015USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of Life Insurance Contract Held in Rabbi Trust | contract		124
Deferred Compensation Plan Assets	$ 59.9	$ 58.1
Deferred Compensation Plan Assets, Death Benefit on Insurance Contracts	150.7	145.8
Deferred Compensation Plan Assets, Loans Outstanding Against Insurance Contracts	44	44.5
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Assets Transferred to (from) Plan		212.9
Defined Benefit Plan, Plan Assets, Payment for Settlement		62.3
Employer contributions	0.8	68	$ 16.7
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement		70.5
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	(45)	(71.1)	$ (8.1)	$ (5.9)
Moody's, Aa1 Rating [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Lower Threshold for Discount Rate Basis, Corporate Bonds		$ 250
United States
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Percentage of Projected Benefit Obligation		38.60%
OUS
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred Compensation Plan Assets, Collateral For Plan Benefits	$ 7.7	$ 8.8

Retirement Plans (Schedule of N

Retirement Plans (Schedule of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment	$ 0		$ 0	$ 0
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.8	$ 1.4	1.8	2.4
Interest cost	2	2.3	13.2	14.5
Expected return on plan assets	(2.3)	(1.3)	(16.7)	(18.9)
Amortization of net actuarial loss	3.5	2.7	11.3	9.2
Amortization of prior service cost	0.1	0.2	0	0
Loss on plan settlements	45	71.1	8.1	5.9
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment		(1)
Net period benefit cost (credit)	49.1	75.4	17.7	13.1
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.1	0	0.1	0.1
Interest cost	0.4	1.7	2	1.9
Amortization of prior service cost	(0.5)	(2)	(2.1)	(4)
Loss on plan settlements	0	(0.9)	0	0
Net period benefit cost (credit)	$ 0	$ (1.2)	$ 0	$ (2)

Retirement Plans (Schedule of B

Retirement Plans (Schedule of Benefit Obligation, Plan Assets and Funded Status of Plans) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Dec. 30, 2016	Sep. 30, 2016	Sep. 25, 2015
Pension Benefits
Change in benefit obligations:
Projected benefit obligations at beginning of year	$ 409.1	$ 257.4		$ 375.5
Service cost	0.8	1.4		1.8	$ 2.4
Interest cost	2	2.3		13.2	14.5
Actuarial (gain) loss	(23.2)	(9)		65.5
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(5.3)	(9.4)		(20.1)
Plan settlements	(125.9)	(217)		(26.5)
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	0		(0.4)
Net transfer in	1.1	0		0
Currency translation	(1.2)	2.1		0.1
Projected benefit obligations at end of year	257.4	27.8	$ 257.4	409.1	375.5
Change in plan assets:
Fair value of plan assets at beginning of year	309.5	161		309.9
Actual return on plan assets	(18.1)	0.3		29.5
Employer contributions	0.8	68		16.7
Defined Benefit Plan, Plan Assets, Benefits Paid	(5.3)	(9.4)		(20.1)
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Assets Transferred to (from) Plan	0	(2.9)		0
Plan settlements	(125.9)	(217)		(26.5)
Fair value of plan assets at end of year	161	0	161	309.5	309.9
Funded status at end of year	(96.4)	(27.8)	(96.4)	(99.6)
Postretirement Benefits
Change in benefit obligations:
Projected benefit obligations at beginning of year	50.8	47.5		52.2
Service cost	0.1	0		0.1	0.1
Interest cost	0.4	1.7		2	1.9
Actuarial (gain) loss	(2.8)	0.2		0.5
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(1)	(2.9)		(4)
Plan settlements	0	(0.9)		0
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment	0	0		0
Net transfer in	0	0		0
Currency translation	0	0		0
Projected benefit obligations at end of year	47.5	45.6	47.5	50.8	52.2
Change in plan assets:
Fair value of plan assets at beginning of year	0	0	0	0
Actual return on plan assets		0	0	0
Employer contributions		2.9	1	4
Defined Benefit Plan, Plan Assets, Benefits Paid		(2.9)	(1)	(4)
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Assets Transferred to (from) Plan				0
Plan settlements		0	0	0
Fair value of plan assets at end of year	0	0	0	0	$ 0
Funded status at end of year	$ (47.5)	$ (45.6)	$ (47.5)	$ (50.8)

Retirement Plans (Schedule of A

Retirement Plans (Schedule of Amounts Recognized in Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 29, 2017	Dec. 30, 2016
Amounts recognized on the consolidated balance sheet:
Non-current liabilities	$ (67.1)	$ (136.4)
Pension Benefits
Amounts recognized on the consolidated balance sheet:
Non-current assets	0	1.4
Current liabilities	(2.4)	(5.5)
Non-current liabilities	(25.4)	(92.3)
Net amount recognized on the consolidated balance sheet	(27.8)	(96.4)
Amounts recognized in accumulated other comprehensive income consist of:
Net actuarial loss	(8.6)	(89.7)
Prior service (cost) credit	(0.5)	0.4
Net amount recognized in accumulated other comprehensive income	(9.1)	(89.3)
Postretirement Benefits
Amounts recognized on the consolidated balance sheet:
Non-current assets	0	0
Current liabilities	(3.9)	(4.2)
Non-current liabilities	(41.7)	(43.3)
Net amount recognized on the consolidated balance sheet	(45.6)	(47.5)
Amounts recognized in accumulated other comprehensive income consist of:
Net actuarial loss	(3)	(2.8)
Prior service (cost) credit	10.2	12.3
Net amount recognized in accumulated other comprehensive income	$ 7.2	$ 9.5

Retirement Plans (Schedule o104

Retirement Plans (Schedule of Amounts to be Amortized From Accumulated Other Comprehensive Income) (Details) $ in Millions	Dec. 29, 2017USD ($)
Pension Benefits
Defined Benefit Plan, Expected Amortization, Next Fiscal Year [Abstract]
Amortization of net actuarial loss	$ (0.5)
Amortization of prior service (cost) credit	(0.1)
Postretirement Benefits
Defined Benefit Plan, Expected Amortization, Next Fiscal Year [Abstract]
Amortization of net actuarial loss	(0.1)
Amortization of prior service (cost) credit	$ 2.1

Retirement Plans (Schedule of P

Retirement Plans (Schedule of Plans with Accumulated Benefit Obligations in Excess of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 29, 2017	Dec. 30, 2016
Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Accumulated benefit obligation	$ 27.3	$ 251.2
Fair value of plan assets	$ 0	$ 153.8

Retirement Plans (Schedule o106

Retirement Plans (Schedule of Actuarial Assumptions) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
U.S.
Weighted Average-Assumptions Used in Calculating Net Periodic Benefit Cost
Discount rate	2.20%	3.00%	3.90%	3.80%
Expected return on plan assets	3.50%	3.50%	5.80%	6.00%
Rate of compensation increase	0.00%	0.00%	0.00%	0.00%
Weighted-Average Assumptions Used in Calculating Benefit Obligations
Discount rate	3.00%	3.30%	2.30%	3.90%
Rate of compensation increase	0.00%	0.00%	0.00%	0.00%
OUS
Weighted Average-Assumptions Used in Calculating Net Periodic Benefit Cost
Discount rate	1.30%	1.80%	2.00%	2.40%
Expected return on plan assets	0.00%	0.00%	2.00%	2.00%
Rate of compensation increase	0.00%	2.50%	0.00%	0.00%
Weighted-Average Assumptions Used in Calculating Benefit Obligations
Discount rate	1.80%	1.90%	1.30%	2.40%
Rate of compensation increase	0.30%	2.50%	0.00%	0.00%
Postretirement Benefits
Weighted Average-Assumptions Used in Calculating Net Periodic Benefit Cost
Discount rate	3.20%	3.70%	4.00%	3.60%
Weighted-Average Assumptions Used in Calculating Benefit Obligations
Discount rate	3.80%	3.40%	3.20%	3.90%
Healthcare Cost Trend Assumptions
Healthcare cost trend rate assumed for next fiscal year	6.90%	6.90%
Rate to which the cost trend rate is assumed to decline	4.50%	4.50%
Fiscal year the ultimate trend rate is achieved	2,038	2,038
Effect of One-Percentage Point Change in Assumed Healthcare Cost Trend Rates
One-Percentage-Point Increase, effect on total of service and interest cost		$ 0
One-Percentage-Point Decrease, effect on total of service and interest cost		0
One-Percentage-Point Increase, effect on postretirement benefit obligation		0.2
One-Percentage-Point Decrease, effect on postretirement obligation		$ (0.4)

Retirement Plans (Schedule of F

Retirement Plans (Schedule of Fair Value of Plan Assets) (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Dec. 30, 2016	Dec. 29, 2017	Dec. 30, 2016	Sep. 30, 2016	Sep. 25, 2015
Recurring
Defined Benefit Plan Disclosure [Line Items]
Pension plans, weighted-average plan asset allocation		100.00%		100.00%
Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year			$ 161
Fair value of plan assets at end of year		$ 161		$ 161
Recurring | U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Pension plans, weighted-average plan asset allocation		1.00%		1.00%
Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year			1.7
Fair value of plan assets at end of year		$ 1.7		$ 1.7
Recurring | Diversified Fixed Income Funds
Defined Benefit Plan Disclosure [Line Items]
Pension plans, weighted-average plan asset allocation		92.00%		92.00%
Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	[1]		148.3
Fair value of plan assets at end of year	[1]	$ 148.3		$ 148.3
Recurring | Other Assets
Defined Benefit Plan Disclosure [Line Items]
Pension plans, weighted-average plan asset allocation		7.00%		7.00%
Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year			11
Fair value of plan assets at end of year		$ 11		$ 11
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation		257.4	27.8	257.4	$ 409.1	$ 375.5
Defined Benefit Plan, Plan Assets, Benefits Paid		(5.3)	(9.4)		(20.1)
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(5.3)	(9.4)		(20.1)
Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year		309.5	161		309.9
Fair value of plan assets at end of year		161	0	161	309.5	309.9
Defined Benefit Plan, Service Cost		0.8	1.4		1.8	2.4
Interest cost		2	2.3		13.2	14.5
Actuarial (gain) loss		(23.2)	(9)		65.5
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement		125.9	217		26.5
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment		0	0		0.4
Net transfer in		1.1	0		0
Currency translation		(1.2)	2.1		0.1
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation		47.5	45.6	47.5	50.8	52.2
Defined Benefit Plan, Plan Assets, Benefits Paid			(2.9)	(1)	(4)
Defined Benefit Plan, Benefit Obligation, Benefits Paid		(1)	(2.9)		(4)
Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year		0	0	0	0
Fair value of plan assets at end of year		0	0	$ 0	0	0
Defined Benefit Plan, Service Cost		0.1	0		0.1	0.1
Interest cost		0.4	1.7		2	$ 1.9
Actuarial (gain) loss		(2.8)	0.2		0.5
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement		0	0.9		0
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment		0	0		0
Net transfer in		0	0		0
Currency translation		$ 0	$ 0		$ 0
[1]	Diversified fixed income funds consist of U.S. Treasury bonds, mortgage-backed securities, corporate bonds, asset-backed securities and U.S. agency bonds.

Retirement Plans (Schedule of E

Retirement Plans (Schedule of Expected Benefit Payments) (Details) $ in Millions	Dec. 29, 2017USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fiscal 2,018	$ 2.4
Fiscal 2,019	1.8
Fiscal 2,020	1.8
Fiscal 2,021	1.7
Fiscal 2,022	1.6
Fiscal 2023-2027	7.5
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fiscal 2,018	3.9
Fiscal 2,019	3.7
Fiscal 2,020	3.5
Fiscal 2,021	3.3
Fiscal 2,022	3.2
Fiscal 2023-2027	$ 14.2

Retirement Plans (Defined Contr

Retirement Plans (Defined Contribution Plan) (Details) - Defined Contribution Plan, 401 K [Member] - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution, percent of match		50.00%
Defined Contribution Plan, Cost	$ 4.2	$ 25.2	$ 25.3	$ 22.1

Equity (Details)

Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015	Mar. 01, 2017	Mar. 16, 2016	Nov. 19, 2015	Jan. 23, 2015
Class of Stock [Line Items]
Preferred shares, shares authorized (in shares)	500,000,000	500,000,000	500,000,000
Preferred shares, par value (in usd per share)	$ 0.20	$ 0.20	$ 0.20
Preferred shares, shares issued (in shares)	0	0	0
Employee Service Share-based Compensation, Cash Flow Effect, Cash Used to Settle Awards	$ 0.4	$ 5.1	$ 2.3	$ 17.2
Treasury Stock, Shares, Canceled		26,500,000
Treasury Stock, Canceled, Value		$ 5.3
November 2015 Share Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount							$ 500
January 2015 Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount								$ 300
March 2016 Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount						$ 350
March 2017 Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount					$ 1,000

Equity Stock Repurchase Program

Equity Stock Repurchase Program (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015	Mar. 01, 2017	Mar. 16, 2016	Nov. 19, 2015	Jan. 23, 2015
Class of Stock [Line Items]
Employee Service Share-based Compensation, Cash Flow Effect, Cash Used to Settle Awards	$ 0.4	$ 5.1	$ 2.3	$ 17.2
March 2016 Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount						$ 350
Repurchase of ordinary shares, shares	1,501,676	5,366,741	0	0
Repurchase of ordinary shares, value	$ 84	$ 266	$ 0	$ 0
Stock Repurchase Program, Remaining Authorized Repurchase Amount			$ 0
November 2015 Share Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount							$ 500
Repurchase of ordinary shares, shares	1,063,337	0	6,510,824	0
Repurchase of ordinary shares, value	$ 74.4	$ 0	$ 425.6	$ 0
Stock Repurchase Program, Remaining Authorized Repurchase Amount			$ 0
January 2015 Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount								$ 300
Repurchase of ordinary shares, shares	0	0	3,199,279	823,592
Repurchase of ordinary shares, value	$ 0	$ 0	$ 225	$ 75
Stock Repurchase Program, Remaining Authorized Repurchase Amount			$ 0
March 2017 Repurchase Program [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount					$ 1,000
Repurchase of ordinary shares, shares	0	13,490,448	0	0
Repurchase of ordinary shares, value	$ 0	$ 380.6	$ 0	$ 0
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 619.4

Share Plans (Narrative) (Detail

Share Plans (Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation cost	$ 10,600,000	$ 58,500,000	$ 41,400,000	$ 115,000,000
Tax benefit from share-based compensation cost	3,600,000	11,000,000	13,100,000	41,300,000
Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options		16,000,000
Employee Service Share-based Compensation, Tax Benefit from U.S. Tax Reform Measurement		5,000,000
Intrinsic value of options vested	300,000	1,400,000	15,300,000	89,500,000
Tax benefit from stock options exercised	$ 100,000	$ 500,000	$ 5,700,000	$ 33,100,000
Performance period		3 years
Share Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years
Expiration period		10 years
Unrecognized compensation cost, share options		$ 37,700,000
Weighted-average period to recognize unrecognized compensation cost, share options		2 years 6 months
Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value, granted restricted share units	$ 69.08	$ 50.74	$ 70.10	$ 105.68
Vesting period		4 years
Weighted-average period to recognize unrecognized compensation cost, share options		2 years 5 months
Fair value of restricted share units granted in period		$ 50,700,000
Fair value of restricted share units vested in period		69,100,000
Unrecognized compensation cost, restricted share units		$ 42,000,000
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer matching contribution, percent of match				25.00%	15.00%
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date		15.00%
ESPP employer match - maximum employee contribution				$ 25,000
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value, granted restricted share units		$ 51.73	$ 83	$ 125.84
Unrecognized compensation cost		$ 18,500,000
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value, granted restricted share units		$ 70.88
Fair value of restricted share units vested in period		$ 400,000
2013 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized under 2013 Plan		5,700,000
2015 Mallinckrodt Pharmaceuticals Stock and Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized under 2013 Plan		17,800,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized		12,100,000
Questcor Pharmaceuticals, Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Post combination expense				$ 90,400,000
Selling, general and administrative | Questcor Pharmaceuticals, Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Post combination expense				80,600,000
Restructuring | Questcor Pharmaceuticals, Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Post combination expense				$ 9,800,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of ordinary shares to be awarded		0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of ordinary shares to be awarded		200.00%
New ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount		$ 25,000

Share Plans (Schedule of Incent

Share Plans (Schedule of Incentive Equity Awards Issued Upon Completion of Conversion) (Details) - $ / shares	Dec. 29, 2017	Dec. 30, 2016	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share options outstanding	4,643,984	3,386,694	3,421,856	2,786,443	3,526,789
Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value, restricted share units	$ 60.08	$ 71.03	$ 70.40	$ 73.45	$ 47.88

Share Plans (Schedule of Share

Share Plans (Schedule of Share Option Award Status Upon Completion of the Conversion) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 29, 2017	Dec. 30, 2016	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share options outstanding	4,643,984	3,386,694	3,421,856	2,786,443	3,526,789
Weighted-average exercise price, outstanding share options	$ 57.78	$ 61.24	$ 61.17	$ 52.76	$ 36.84
Weighted-average remaining contractual term, outstanding share options	6 years 11 months
Aggregate intrinsic value, outstanding share options	$ 0.2
Share options exerciseable	1,944,709
Weighted-average exercise price, exercisable share options	$ 52.19
Weighted-average remaining contractual term, exercisable share options	4 years 8 months
Aggregate intrinsic value, exercisable share options	$ 0.2

Share Plans (Schedule of the Va

Share Plans (Schedule of the Valuation Assumptions Used in the Conversion) (Details) - $ / shares	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014
Weighted Average Assumptions
Expected share price volatility	35.00%	36.00%	31.00%	29.00%
Risk-free interest rate	1.23%	2.00%	1.74%	1.72%
Expected annual dividend per share	0.00%	0.00%	0.00%	0.00%
Expected life of options (in years)	5 years 3 months	5 years 3 months	5 years 4 months	5 years 4 months
Fair value per option	$ 20.04	$ 18.36	$ 22.82	$ 30.08
Share options outstanding	3,386,694	4,643,984	3,421,856	2,786,443	3,526,789

Share Plans (Schedule of Sha116

Share Plans (Schedule of Share Option Activity) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Intrinsic value of options vested	$ 0.3	$ 1.4	$ 15.3	$ 89.5
Share Option Activity [Roll Forward]
Beginning balance	3,421,856	3,386,694	2,786,443	3,526,789
Granted	3,742	1,719,532	1,248,828	635,567
Exercised	(16,382)	(113,605)	(413,830)	(1,132,778)
Expired/Forfeited	(22,522)	(348,637)	(199,585)	(243,135)
Ending balance	3,386,694	4,643,984	3,421,856	2,786,443
Share options vested and unvested expected to vest		3,882,733
Share options exerciseable		1,944,709
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted-average exercise price, outstanding share options	$ 61.24	$ 57.78	$ 61.17	$ 52.76	$ 36.84
Weighted-average exercise price, granted share options	60.01	51.57	72.44	102.20
Weighted-average exercise price, exercised share options	36.42	47.74	32.76	29.79
Weighted-average exercise price, expired and forfeited share options	$ 70.82	68.08	$ 72.65	$ 58
Weighted-average exercise price, vested and unvested expected to vest share options		60.62
Weighted-average exercise price, exercisable share options		$ 52.19
Weighted-average remaining contractual term, outstanding share options		6 years 11 months
Weighted-average remaining contractual term, vested and unvested expected to vest share options		7 years 6 months
Weighted-average remaining contractual term, exercisable share options		4 years 8 months
Aggregate intrinsic value, outstanding share options		$ 0.2
Aggregate intrinsic value, vested and unvested expected to vest share options		(0.6)
Aggregate intrinsic value, exercisable share options		0.2
Tax benefit from stock options exercised	$ 0.1	$ 0.5	$ 5.7	$ 33.1

Share Plans (Schedule of Restri

Share Plans (Schedule of Restricted Share Unit Activity) (Details) - $ / shares	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014
Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average period to recognize unrecognized compensation cost, share options		2 years 5 months
Restricted Share Unit Activity [Roll Forward]
Beginning balance	894,459	883,462	572,494	589,222
Granted	36,731	655,282	615,074	273,733
Exercised	(30,919)	(263,189)	(193,849)	(219,189)
Expired/Forfeited	(16,809)	(169,789)	(99,260)	(71,272)
Ending balance	883,462	1,105,766	894,459	572,494
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted-average grant date fair value, restricted share units	$ 71.03	$ 60.08	$ 70.40	$ 73.45	$ 47.88
Weighted-average grant date fair value, granted restricted share units	69.08	50.74	70.10	105.68
Weighted-average grant date fair value, vested restricted share units	47.54	69.14	69.27	49.84
Weighted-average grant date fair value, forfeited restricted share units	$ 49.62	$ 68.57	$ 79.95	$ 68.15
Restricted Stock
Restricted Share Unit Activity [Roll Forward]
Beginning balance	16,866	14,868	34,562	1,432,031
Exercised	(1,087)	(7,970)	(9,760)	(1,362,823)
Expired/Forfeited	(911)	(2,223)	(7,936)	(34,646)
Ending balance	14,868	4,675	16,866	34,562
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted-average grant date fair value, granted restricted share units		$ 70.88

Share Plans (Schedule of Perfor

Share Plans (Schedule of Performance Share Unit Activity) (Details) - $ / shares		3 Months Ended		12 Months Ended
		Dec. 30, 2016		Dec. 29, 2017		Sep. 30, 2016		Sep. 25, 2015	Sep. 26, 2014
Performance Shares
Performance Share Unit Activity [Roll Forward]
Beginning balance		266,645	[1]	265,648	[1]	130,974	[1]	72,740
Granted				348,963		145,192	[1]	77,306
Exercised	[1]			(61,554)
Expired/Forfeited		(997)	[1]	(48,606)	[1]	(9,521)	[1]	(19,072)
Ending balance	[1]	265,648		504,451		266,645		130,974
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted-average grant date fair value, restricted share units		$ 88.51		$ 64.44		$ 88.59		$ 96.05	$ 63.46
Weighted-average grant date fair value, granted restricted share units				51.73		83		125.84
Weighted-average grant date fair value, vested restricted share units				62.65
Weighted-average grant date fair value, forfeited restricted share units		$ 154.42		$ 107		$ 96.30		$ 92.05
Restricted Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms				1 year 10 months
Weighted-average period to recognize unrecognized compensation cost, share options				2 years 5 months
Performance Share Unit Activity [Roll Forward]
Beginning balance		894,459		883,462		572,494		589,222
Granted		36,731		655,282		615,074		273,733
Exercised		(30,919)		(263,189)		(193,849)		(219,189)
Expired/Forfeited		(16,809)		(169,789)		(99,260)		(71,272)
Ending balance		883,462		1,105,766		894,459		572,494
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted-average grant date fair value, restricted share units		$ 71.03		$ 60.08		$ 70.40		$ 73.45	$ 47.88
Weighted-average grant date fair value, granted restricted share units		69.08		50.74		70.10		105.68
Weighted-average grant date fair value, vested restricted share units		47.54		69.14		69.27		49.84
Weighted-average grant date fair value, forfeited restricted share units		$ 49.62		$ 68.57		$ 79.95		$ 68.15
[1]	The number of shares disclosed within this table are at the target number of 100%.

Share Plans (Schedule of Fair V

Share Plans (Schedule of Fair Value Assumptions for Performance Share Unit) (Details) - Performance Shares	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected stock price volatility	48.00%	48.00%	41.00%	27.00%
Peer group stock price volatility	40.00%	40.00%	36.00%	32.00%
Correlation of returns	17.00%	17.00%	24.00%	14.00%

Share Plans (Schedule of Res120

Share Plans (Schedule of Restricted Stock Award Activity) (Details) - Restricted Stock - $ / shares	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Restricted Stock Activity [Roll Forward]
Beginning balance	16,866	14,868	34,562	1,432,031
Exercised	(1,087)	(7,970)	(9,760)	(1,362,823)
Expired/Forfeited	(911)	(2,223)	(7,936)	(34,646)
Ending balance	14,868	4,675	16,866	34,562
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted-average grant date fair value, granted restricted share units		$ 70.88

Accumulated Other Comprehens121

Accumulated Other Comprehensive Income (Schedule of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ (85.6)	$ (72.5)	$ 0.9
Other comprehensive loss before reclassifications	(15.8)	22.7	(38.7)
Amounts reclassified from accumulated other comprehensive income	28.9	36.9	(47.8)
Ending balance	(72.5)	(12.9)	(85.6)
Currency Translation
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	1.6	(19.5)	60.2
Other comprehensive loss before reclassifications	(21.1)	16	0.8
Amounts reclassified from accumulated other comprehensive income	0	(4.7)	(59.4)
Ending balance	(19.5)	(8.2)	1.6
Unrecognized Loss on Derivatives
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(5.9)	(5.7)	(6.4)
Other comprehensive loss before reclassifications	0	0	0
Amounts reclassified from accumulated other comprehensive income	0.2	1	0.5
Ending balance	(5.7)	(4.7)	(5.9)
Unrecognized Gain (Loss) on Benefit Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(81.3)	(47.3)	(52.9)
Other comprehensive loss before reclassifications	5.3	5.2	(39.5)
Amounts reclassified from accumulated other comprehensive income	28.7	40.6	11.1
Ending balance	(47.3)	(1.5)	(81.3)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	0	0	0
Other comprehensive loss before reclassifications	0	0	0
Amounts reclassified from accumulated other comprehensive income	0		0
Ending balance	$ 0	$ 1.5	$ 0

Accumulated Other Comprehens122

Accumulated Other Comprehensive Income (Schedule of Reclassifications out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017		Sep. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of unrealized loss on derivatives	$ 0.2	$ 1.3		$ 0.7
Income tax provision	0	(0.3)		(0.2)
Net of income taxes	0.2	1		0.5
Amortization of pension and post-retirement benefit plans:
Net actuarial loss	1	2.7	[1]	11.4
Prior service credit	(0.6)	(1.9)	[1]	(2.7)
Plan settlements	45	70.2	[1]	8.1
Total before tax	45.4	67.9		17.6
Income tax provision	(16.7)	(27.3)		(6.5)
Net of income taxes	28.7	40.6		11.1
Total reclassifications for the period	28.9	36.9		(47.8)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent	0	(3.1)		0.8
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax	$ 0	$ (4.7)		$ (59.4)
[1]	These accumulated other comprehensive income components are included in the computation of net periodic benefit cost. See Note 14 for additional details.

Guarantees (Narrative) (Details

Guarantees (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 29, 2017	Dec. 30, 2016	Sep. 25, 2015
Guarantor Obligations [Line Items]
Restricted Cash and Cash Equivalents, Current	$ 0
Others
Guarantor Obligations [Line Items]
Maximum future payments	$ 28.7
Mallinckrodt Baker | Indemnification Agreement
Guarantor Obligations [Line Items]
Guarantor obligations, obligation term	17 years
Maximum future payments	$ 70.2
Escrow	30
Mallinckrodt Baker | Indemnification Agreement | Other Liabilities
Guarantor Obligations [Line Items]
Guarantors obligation	14.9	$ 15.1	$ 15.7
Mallinckrodt Baker | Indemnification Agreement | Other Assets
Guarantor Obligations [Line Items]
Escrow	18.3	19	$ 19
Mallinckrodt Baker | Enviornmental, Health and Safety Matters | Indemnification Agreement | Other Liabilities
Guarantor Obligations [Line Items]
Guarantors obligation	$ 12.1	$ 12.4

Guarantees Non-Printing (Detail

Guarantees Non-Printing (Details) - Mallinckrodt Baker - Indemnification Agreement - USD ($) $ in Millions	Dec. 29, 2017	Dec. 30, 2016	Sep. 25, 2015
Escrow	$ 30
Other Liabilities
Guarantors obligation	14.9	$ 15.1	$ 15.7
Other Assets
Escrow	$ 18.3	$ 19	$ 19

Commitments and Contingencie125

Commitments and Contingencies (Narrative) (Details)	Sep. 26, 2012action	Aug. 31, 2013lawsuitCase	Aug. 31, 2012principal	Dec. 30, 2016USD ($)	Jun. 26, 2015USD ($)	Dec. 29, 2017USD ($)lawsuitCase	Sep. 30, 2016USD ($)Defendent	Sep. 25, 2015USD ($)Defendentorder	Apr. 11, 2014USD ($)	Mar. 28, 2014USD ($)
Loss Contingencies [Line Items]
Payments for Legal Settlements						$ 35,000,000
Litigation Settlement, Expense				$ 102,000,000
Environmental liabilities						75,400,000
Plant Assets Exchanged for Industrial Revenue Bonds						16,000,000
Deferred Tax Liabilities Installment Sales				1,801,400,000		553,600,000
Increase (Decrease) Deferred Tax Liability Resulting From Legal Reorganization						679,300,000
Increase (Decrease) Deferred Tax Liability Resulting From Tax Reform						351,800,000
Increase (Decrease) Deferred Tax Liability Resulting from Installment Note Payments						(270,600,000)
Interest Expense, Installment Sales				15,900,000		69,300,000	$ 73,800,000	$ 36,500,000
Installment note deferred asset write off, net						8,400,000
Interest Payable, Installment Sales				30,300,000		46,000,000
Rent expense				7,200,000		30,400,000	$ 23,900,000	22,200,000
Tax Matters Agreement | Covidien
Loss Contingencies [Line Items]
Tax agreement, tax threshold						$ 200,000,000
Lower Passaic River, New Jersey
Loss Contingencies [Line Items]
Number of defendants | Defendent							98
Environmental liabilities										$ 13,300,000
Remedial cost, estimate							$ 1,380,000,000
Asbestos Matters
Loss Contingencies [Line Items]
Pending claims | Case						11,600
Estimation of liability, historical term						5 years
Estimation of liability, expected future term of claims						7 years
Other current liabilities
Loss Contingencies [Line Items]
Environmental liabilities, current						$ 2,200,000
opioid crisis [Member]
Loss Contingencies [Line Items]
Loss Contingency, Number of Plaintiffs | lawsuit						262
Loss contingency, number of plaintiffs, state court						18
Retrophin Litigation [Member]
Loss Contingencies [Line Items]
Litigation Settlement, Expense								$ 15,500,000
Glenridge Litigation
Loss Contingencies [Line Items]
Number of defendants | principal			3
Loss Contingency, Lawsuits, Number | lawsuit		2
Pending claims | Case		1
Questcor Securities Litigation [Member]
Loss Contingencies [Line Items]
Filed-actions consolidated into the lawsuit | action	4
Litigation Settlement, Amount (Deprecated 2017-01-31)					$ 38,000,000
Loss Contingency, Accrual, Current					$ 38,000,000
Mallinckrodt Veterinary, Inc., Millsboro, Delaware
Loss Contingencies [Line Items]
Number of Administrative Orders of Consent Entered Into | order								2
Lower Passaic River, New Jersey
Loss Contingencies [Line Items]
Number of defendants | Defendent								70
Environmental liabilities									$ 23,100,000
Remedial cost, estimate									1,700,000,000
Intrathecal Therapy [Member]
Loss Contingencies [Line Items]
Increase (Decrease) Deferred Tax Liability Resulting From Installment Sale Transaction						$ 53,900,000
Minimum
Loss Contingencies [Line Items]
Remedial cost, estimate						37,600,000
Minimum | Lower Passaic River, New Jersey
Loss Contingencies [Line Items]
Remedial cost, estimate								$ 483,400,000	365,000,000
Maximum
Loss Contingencies [Line Items]
Remedial cost, estimate						$ 115,500,000
Maximum | Lower Passaic River, New Jersey
Loss Contingencies [Line Items]
Remedial cost, estimate								$ 2,700,000,000	$ 3,200,000,000
Recurring | Level 3 | Stratatech [Member]
Loss Contingencies [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Contingent Liability				$ 55,700,000			$ 53,500,000

Commitments and Contingencie126

Commitments and Contingencies (Schedule of Purchase Oligations) (Details) $ in Millions	Dec. 29, 2017USD ($)
Unrecorded Unconditional Purchase Obligation [Line Items]
Fiscal 2,018	$ 122.6
Fiscal 2,019	72.3
Fiscal 2,020	60.9
Fiscal 2,021	16.1
Fiscal 2,022	$ 15.4

Commitments and Contingencie127

Commitments and Contingencies (Schedule of Minimum Lease Payments for Non-cancelable Leases) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$ 7.2	$ 30.4	$ 23.9	$ 22.2
Operating Leases
Operating leases, fiscal 2018		23.1
Operating leases, fiscal 2019		19.2
Operating leases, fiscal 2020		17.4
Operating leases, fiscal 2021		15.8
Operating leases, fiscal 2022		13.8
Operating leases, thereafter		61.6
Operating Leases, Future Minimum Payments Due		150.9
Capital Leases
Capital leases, fiscal 2018		0.2
Capital leases, fiscal 2019		0
Capital leases, fiscal 2020		0
Capital leases, fiscal 2021		0
Capital leases, fiscal 2022		0
Capital leases, thereafter		0
Capital leases, total minimum lease payments		$ 0.2

Financial Instruments and Fa128

Financial Instruments and Fair Value Measurements (Narrative) (Details) CAD in Millions, $ in Millions	12 Months Ended
	Dec. 29, 2017USD ($)	Sep. 30, 2016CAD	Sep. 25, 2015CAD	Dec. 11, 2017USD ($)	Sep. 25, 2017USD ($)	Dec. 30, 2016USD ($)	Sep. 30, 2016USD ($)	Aug. 31, 2016USD ($)	Feb. 01, 2016USD ($)	Aug. 31, 2014USD ($)	Apr. 30, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Liability, Current	$ 64
Business Combination, Contingent Consideration, Liability, Noncurrent	182.4
Notes, Loans and Financing Receivable, Net, Current	154					$ 0
Novartis 2015 and 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Annual Payments	25
Novartis, Subsequent to 2016 till FDA Approval
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Annual Payments	25
Novartis, Subsequent to FDA Approval
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Contingent Consideration, Potential Payment	25
Questcor Pharmaceuticals, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Maximum contingent payments for acquisition	$ 140
Discount rate	4.70%
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Contingent Liability	$ 111.8					124.7				$ 195.4
Hemostasis Products
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition									$ 52
Maximum contingent payments for acquisition									$ 395
Stratatech [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition								$ 54.9
Maximum contingent payments for acquisition								$ 121
InfaCare [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition					$ 35
Maximum contingent payments for acquisition					$ 345
Ocera [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition				$ 22
Maximum contingent payments for acquisition				75
4.00% term loan due February 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	4.00%
Debentures | 8.00% debentures due March 2023 | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	8.00%
Debentures | 9.50% debentures due May 2022 | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	9.50%
Senior Notes | 3.50% notes due April 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate											3.50%
Senior Notes | 3.50% notes due April 2018 | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	3.50%
Senior Notes | 4.75% notes due April 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate											4.75%
Senior Notes | 4.75% notes due April 2023 | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	4.75%
Senior Notes | 5.75% notes due August 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount rate	5.75%
Stated interest rate										5.75%
Debentures | Four Point Eight Eight Percent Notes [Member] | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	4.875%
Debentures | Five Point Five Percent Notes [Member] | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	5.50%
Debentures | 5.625% notes due October 2023 | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	5.625%
Carrying Value | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash	$ 18.3					19.1
Carrying Value | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash surrender value of life insurance	67					67.6
BioVectra Inc [Member] | Questcor Pharmaceuticals, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition | CAD			CAD 50
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements | CAD		CAD 40	CAD 5
Raplixa [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Fair Value Adjustment	54.6
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition	246.4					250.5
Debt and equity securities held in rabbi trusts	35.4					33.6
Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition	0					0
Debt and equity securities held in rabbi trusts	24					22.8
Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition	0					0
Debt and equity securities held in rabbi trusts	11.4					10.8
Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition	246.4					250.5
Debt and equity securities held in rabbi trusts	0					0
Recurring | Level 3 | Stratatech [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Contingent Liability						55.7	$ 53.5
Recurring | PreveLeak [Member] | Level 3 | Hemostasis Products
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Contingent Liability	17.1					11.2
Recurring | Raplixa [Member] | Level 3 | Hemostasis Products
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition	7					58.9
Recurring | Stannsoporfin [Member] | Level 3 | InfaCare [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition	35
Recurring | MNK-6105 [Member] | Level 3 | Ocera [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition				$ 22
Contingent Consideration | Recurring | Questcor Pharmaceuticals, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value						250.5
Contingent Consideration | Recurring | Total Acquisitions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	246.4
Other Assets | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt and equity securities held in rabbi trusts	$ 0					$ 11.1

(Schedule of Fair Value of Asse

(Schedule of Fair Value of Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - Recurring - USD ($) $ in Millions	Dec. 29, 2017	Dec. 30, 2016
Assets:
Debt and equity securities held in rabbi trusts	$ 35.4	$ 33.6
Other Assets, Fair Value Disclosure	22.7	0.7
Foreign Currency Contract, Asset, Fair Value Disclosure	0.1
Total assets at fair value	58.2	34.3
Liabilities:
Deferred compensation liabilities	42.7	32.5
Contingent consideration	246.4	250.5
Foreign exchange forward and option contracts	0.1	3.4
Total liabilities at fair value	289.2	286.4
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Debt and equity securities held in rabbi trusts	24	22.8
Other Assets, Fair Value Disclosure	22.7	0.7
Foreign Currency Contract, Asset, Fair Value Disclosure	0.1
Total assets at fair value	46.8	23.5
Liabilities:
Deferred compensation liabilities	0	0
Contingent consideration	0	0
Foreign exchange forward and option contracts	0.1	3.4
Total liabilities at fair value	0.1	3.4
Significant Other Observable Inputs (Level 2)
Assets:
Debt and equity securities held in rabbi trusts	11.4	10.8
Other Assets, Fair Value Disclosure	0	0
Foreign Currency Contract, Asset, Fair Value Disclosure	0
Total assets at fair value	11.4	10.8
Liabilities:
Deferred compensation liabilities	42.7	32.5
Contingent consideration	0	0
Foreign exchange forward and option contracts	0	0
Total liabilities at fair value	42.7	32.5
Significant Unobservable Inputs (Level 3)
Assets:
Debt and equity securities held in rabbi trusts	0	0
Other Assets, Fair Value Disclosure	0	0
Foreign Currency Contract, Asset, Fair Value Disclosure	0
Total assets at fair value	0	0
Liabilities:
Deferred compensation liabilities	0	0
Contingent consideration	246.4	250.5
Foreign exchange forward and option contracts	0	0
Total liabilities at fair value	$ 246.4	$ 250.5

(Schedule of Reconciliation of

(Schedule of Reconciliation of Changes in Fair Value of Contingent Consideration) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 29, 2017	Dec. 30, 2016	Sep. 30, 2016	Aug. 31, 2016	Feb. 01, 2016	Aug. 31, 2014
Questcor Pharmaceuticals, Inc.
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Contingent Liability	$ 111.8	$ 124.7				$ 195.4
Hemostasis Products
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration					$ 52
Stratatech [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration				$ 54.9
Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration	246.4	250.5
Recurring | Contingent Consideration | Questcor Pharmaceuticals, Inc.
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	250.5
Payments	(25)
Business Combination, Contingent Consideration, Accretion	5.3
Fair value adjustment	(41.4)
Recurring | Contingent Consideration | Total Acquisitions
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Ending balance	246.4
Level 3 | Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration	246.4	250.5
Level 3 | Recurring | Stratatech [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Contingent Liability		55.7	$ 53.5
Level 3 | Recurring | Contingent Liabilities [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances	57
Raplixa [Member] | Level 3 | Recurring | Hemostasis Products
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration	7	58.9
PreveLeak [Member] | Level 3 | Recurring | Hemostasis Products
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Contingent Liability	$ 17.1	$ 11.2

(Schedule of Carrying Amount an

(Schedule of Carrying Amount and Fair Value of Long-term Debt) (Details) - USD ($) $ in Millions	Dec. 29, 2017	Dec. 30, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Gross	$ 6,492.6	$ 5,965.8
Term loan due March 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan payable	0	1,953.2
Loans Payable	0	1,948.5
4.00% term loan due February 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan payable	0	6.5
Loans Payable	0	6.5
Secured Debt | Variable rate receivable securitization
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Variable rate receivable securitization	0
Secured Debt | Receivable securitization, Maturity Date of July 2020 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Variable rate receivable securitization		0
Long-term Debt, Gross	200	0
Secured Debt | Term loan due March 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Gross	0	1,928.5
Secured Debt | 4.00% term loan due February 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Gross	0	5.5
Secured Debt | New Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loan payable	1,848.7	0
Loans Payable	1,851.2	0
Debentures | 9.50% debentures due May 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	10.9	12
Long-term Debt, Gross	10.4	10.4
Debentures | 8.00% debentures due March 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	4.4	4.9
Long-term Debt, Gross	4.4	4.4
Senior Notes | 3.50% notes due April 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	299.1	298.7
Long-term Debt, Gross	0	300
Senior Notes | 5.75% notes due August 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	804.8	850.3
Long-term Debt, Gross	884	884
Senior Notes | 4.75% notes due April 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	412.4	520.9
Long-term Debt, Gross	526.5	600
Debentures | Four Point Eight Eight Percent Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	675.2	699.5
Long-term Debt, Gross	700	700
Debentures | Five Point Five Percent Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	564.5	615.7
Long-term Debt, Gross	692.1	695
Debentures | 2015 Revolving Credit Facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	900	100
Long-term Debt, Gross	900	100
Debentures | 5.625% notes due October 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term debt	628.8	682.4
Long-term Debt, Gross	738	738
Carrying Value | Variable rate receivable securitization
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Variable rate receivable securitization		250
Fair Value | Variable rate receivable securitization
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Variable rate receivable securitization	0	250
Fair Value | Receivable securitization, Maturity Date of July 2020 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Variable rate receivable securitization	$ 200	$ 0

(Schedules of Concentration of

(Schedules of Concentration of Risk) (Details)	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Distributor Concentration Risk | Net Sales Attributable to Distributors | CuraScript, Inc [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	43.00%	40.00%	38.00%	35.00%
Distributor Concentration Risk | Net Sales Attributable to Distributors | McKesson Corporation [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	10.00%		12.00%	20.00%
Distributor Concentration Risk | Net Sales Attributable to Distributors | Cardinal Health, Inc. [Member]
Concentration Risk [Line Items]
Concentration risk, percentage				11.00%
Distributor Concentration Risk | Net Sales Attributable to Distributors | Amerisource Bergen Corporation [Member]
Concentration Risk [Line Items]
Concentration risk, percentage				10.00%
Distributor Concentration Risk | Accounts Receivable Attributable to Distributors | CuraScript, Inc [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	15.00%	14.00%
Distributor Concentration Risk | Accounts Receivable Attributable to Distributors | McKesson Corporation [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	28.00%	26.00%
Distributor Concentration Risk | Accounts Receivable Attributable to Distributors | Cardinal Health, Inc. [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	10.00%	11.00%
Distributor Concentration Risk | Accounts Receivable Attributable to Distributors | Amerisource Bergen Corporation [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	15.00%	15.00%
Product Concentration Risk | Net Sales Attributable to Products | H.P. Acthar Gel
Concentration Risk [Line Items]
Concentration risk, percentage	39.00%	37.00%	34.00%	35.00%
Product Concentration Risk | Net Sales Attributable to Products | Inomax
Concentration Risk [Line Items]
Concentration risk, percentage	14.00%	16.00%	14.00%	6.00%

Segment and Geographical Dat133

Segment and Geographical Data (Schedule of Segment Reporting Information by Business Segment) (Details) - USD ($) $ in Millions		3 Months Ended										12 Months Ended
		Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016		Sep. 30, 2016	Jun. 24, 2016	Mar. 25, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016		Sep. 25, 2015		Sep. 26, 2014	Sep. 27, 2013
Segment Reporting Information [Line Items]
Net sales		$ 792.3	$ 793.9	$ 824.5	$ 810.9	$ 829.9		$ 887.2	$ 866.6	$ 815.8	$ 811.2	$ 3,221.6	$ 3,380.8		$ 2,923.1
Operating income (loss)						(206.8)					(162.1)	420.1	617.3		353.8
Intangible asset amortization						(175.7)						(694.5)	(700.1)		(550.3)
Restructuring and related charges, net						(5.3)						(36.4)	(38.2)		(45.3)
Non-restructuring impairment						214.3						63.7	16.9		0
Separation costs						0						0	0		0
Assets		$ 15,280.9				15,206.3						15,280.9
Depreciation and amortization						203.2					$ 206	808.3	834.5		672.5
Restructuring and related costs, accelerated depreciation						1.5						5.2	4.9		0.3
Specialty Brands [Member]
Segment Reporting Information [Line Items]
Restructuring and related charges, net						(2.6)						(25.4)	(23.3)		(36.5)
Specialty Generics [Member]
Segment Reporting Information [Line Items]
Restructuring and related charges, net						(0.8)						(7.7)	(3.4)		(4.5)
Operating Segments
Segment Reporting Information [Line Items]
Net sales	[1]					816						3,164.8	3,325.8		2,874.4
Operating income (loss)						369.9						1,386.7	1,542.3		1,232
Depreciation and amortization	[2]					203.2						808.3	813.4		641.1
Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales						603.1						2,325.3	2,300.6		1,622.8
Operating income (loss)						317.2						1,155.2	1,166.2		637.6
Depreciation and amortization	[2]					178.4						708.2	716.6		559.5
Operating Segments | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales						212.9						839.5	1,025.2		1,251.6
Operating income (loss)						52.7						231.5	376.1		594.4
Depreciation and amortization	[2]					24.8						100.1	96.8		81.6
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Net sales	[3]					13.9	[4]					56.8	55	[4]	48.7	[4]
Corporate and allocated expenses	[5]					(181.4)						(172)	(169.8)		(282.6)
Intangible asset amortization						(175.7)						(694.5)	(700.1)		(550.3)
Restructuring and related charges, net	[6]					(5.3)						(36.4)	(38.2)		(45.3)
Non-restructuring impairment						$ (214.3)						(63.7)	$ (16.9)		$ 0
Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales												$ 0					$ 0	$ 0
[1]	Amounts represent sales to external customers. There were no intersegment sales.
[2]	Depreciation for certain shared facilities is allocated based on occupancy percentage.
[3]	Represents net sales from an ongoing, post-divestiture supply agreement with the acquirer of the CMDS business. Amounts for periods prior to the divestiture represent the reclassification of intercompany sales to third-party sales to conform with the expected presentation of the ongoing supply agreement.
[4]	Represents net sales from an ongoing, post-divestiture supply agreement with the acquirer of the CMDS business. Amounts for periods prior to the divestiture represent the reclassification of intercompany sales to third-party sales to conform with the expected presentation of the ongoing supply agreement.
[5]	Includes administration expenses and certain compensation, environmental and other costs not charged to the Company's operating segments.
[6]	Includes restructuring-related accelerated depreciation.

Segment and Geographical Dat134

Segment and Geographical Data (Schedule of Net Sales from External Costumers by Product) (Details) - USD ($) $ in Millions		3 Months Ended										12 Months Ended
		Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016		Sep. 30, 2016	Jun. 24, 2016	Mar. 25, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016		Sep. 25, 2015
Segment Reporting Information [Line Items]
Net sales		$ 792.3	$ 793.9	$ 824.5	$ 810.9	$ 829.9		$ 887.2	$ 866.6	$ 815.8	$ 811.2	$ 3,221.6	$ 3,380.8		$ 2,923.1
Operating Segments
Segment Reporting Information [Line Items]
Net sales	[1]					816						3,164.8	3,325.8		2,874.4
Operating Segments | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales						212.9						839.5	1,025.2		1,251.6
Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales						603.1						2,325.3	2,300.6		1,622.8
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Net sales	[2]					13.9	[3]					56.8	55	[3]	48.7	[3]
Hydrocodone (API) and hydrocodone-containing tablets | Operating Segments | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales						22						71.7	103.5		136.5
Oxycodone (API) and oxycodone-containing tablets | Operating Segments | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales						24.3						78.8	126.2		154.6
Methylphenidate ER | Operating Segments | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales						23.2						85.3	146.5		167.2
Other controlled substances | Operating Segments | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales						104.9						409.6	468.1		572.2
Other | Operating Segments | Specialty Generics [Member]
Segment Reporting Information [Line Items]
Net sales						38.5						194.1	180.9		221.1
Hemostasis Products | Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales						13.4						55.1	42.5		0
Ofirmev | Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales						72.5						302.5	284.3		263
H.P. Acthar Gel | Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales						325.4						1,195.1	1,160.4		1,037.3
Therakos | Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales						47.4						214.9	207.6		0
Other | Operating Segments | Specialty Brands [Member]
Segment Reporting Information [Line Items]
Net sales						26.1						52.5	131.5		137.3
Product Concentration Risk | Net Sales Attributable to Products | Inomax
Segment Reporting Information [Line Items]
Net sales						$ 118.3						$ 505.2	$ 474.3		$ 185.2
[1]	Amounts represent sales to external customers. There were no intersegment sales.
[2]	Represents net sales from an ongoing, post-divestiture supply agreement with the acquirer of the CMDS business. Amounts for periods prior to the divestiture represent the reclassification of intercompany sales to third-party sales to conform with the expected presentation of the ongoing supply agreement.
[3]	Represents net sales from an ongoing, post-divestiture supply agreement with the acquirer of the CMDS business. Amounts for periods prior to the divestiture represent the reclassification of intercompany sales to third-party sales to conform with the expected presentation of the ongoing supply agreement.

Segment and Geographical Dat135

Segment and Geographical Data (Schedule of Net Sales and Long-Lived Assets by Geographic Area) (Details) - USD ($) $ in Millions		3 Months Ended									12 Months Ended
		Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jun. 24, 2016	Mar. 25, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Net sales		$ 792.3	$ 793.9	$ 824.5	$ 810.9	$ 829.9	$ 887.2	$ 866.6	$ 815.8	$ 811.2	$ 3,221.6	$ 3,380.8	$ 2,923.1
Long-Lived Assets		979				893.5					979
United States
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Net sales	[1]					763.7					2,899	3,095.4	2,647
Long-Lived Assets	[2]	788.5				759.1					788.5
EMEA
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Net sales	[1]					52.8					242.3	211.8	159
Long-Lived Assets	[2],[3]	127				82.9					127
EMEA | IRELAND
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Long-Lived Assets		126				80.9					126
Other Countries
Schedule of Net Sales and Long-Lived Assets by Geographic Area [Line Items]
Net sales	[1]					13.4					80.3	$ 73.6	$ 117.1
Long-Lived Assets	[2]	$ 63.5				$ 51.5					$ 63.5
[1]	Net sales are attributed to regions based on the location of the entity that records the transaction, none of which relate to the country of Ireland.
[2]	Long-lived assets are primarily composed of property, plant and equipment, net.
[3]	Includes long-lived assets located in Ireland of $126.0 million and $80.9 million

Selected Quarterly Financial136

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended																	12 Months Ended
	Dec. 29, 2017		Sep. 29, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 30, 2016	Sep. 30, 2016		Jun. 24, 2016		Mar. 25, 2016		Dec. 25, 2015		Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 792.3		$ 793.9		$ 824.5		$ 810.9		$ 829.9	$ 887.2		$ 866.6		$ 815.8		$ 811.2		$ 3,221.6	$ 3,380.8	$ 2,923.1
Gross profit	421		400.6		416.1		418.6		445.8	490.2		488.8		425.1		450.9		1,656.3	1,855	1,622.9
Income (loss) from continuing operations	1,607.4		64.3		70.6		28.9		(176.8)	110		176.7		98.5		103.8		1,771.2	489	236.6
Income (loss) from discontinued operations, net of income taxes	1.3		(0.6)		(7.8)		370.3		23.6	5		22.6		19.8		107.3		363.2	154.7	88.1
Net income (loss)	$ 1,608.7		$ 63.7		$ 62.8		$ 399.2		$ (153.2)	$ 115		$ 199.3		$ 118.3		$ 211.1		$ 2,134.4	$ 643.7	$ 324.7
Basic earnings (loss) per share from continuing operations (in usd per share)	$ 17.43	[1]	$ 0.66	[1]	$ 0.72	[1]	$ 0.28	[1]	$ (1.67)	$ 1.02	[1]	$ 1.63	[1]	$ 0.89	[1]	$ 0.90	[1]	$ 18.13	$ 4.42	$ 2.03
Diluted earnings (loss) per share from continuing operations (in usd per share)	$ 17.40	[1]	$ 0.66	[1]	$ 0.72	[1]	$ 0.28	[1]	$ (1.67)	$ 1.01	[1]	$ 1.62	[1]	$ 0.88	[1]	$ 0.89	[1]	$ 18.09	$ 4.39	$ 2
[1]	Quarterly and annual computations are prepared independently. Therefore, the sum of each quarter may not necessarily total the fiscal period amounts noted elsewhere within this Annual Report on Form 10-K.

Condensed Consolidating and 137

Condensed Consolidating and Combining Financial Statements (Schedule of Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 29, 2017	Dec. 30, 2016	Sep. 30, 2016	Dec. 25, 2015	Sep. 25, 2015	Sep. 26, 2014
Current Assets:
Cash and cash equivalents	$ 1,260.9	$ 342	$ 280.5	$ 521.9	$ 365.9
Accounts receivable, net	445.8	431
Inventories	340.4	350.7
Deferred income taxes	0	0
Prepaid expenses and other current assets	84.1	131.9
Notes, Loans and Financing Receivable, Net, Current	154	0
Current assets held for sale	0	310.9
Intercompany receivable	0	0
Total current assets	2,285.2	1,566.5
Property, plant and equipment, net	966.8	881.5
Goodwill	3,482.7	3,498.1
Intangible assets, net	8,375	9,000.5
Long-term assets held for sale	0	0
Investment in subsidiaries	0	0
Intercompany loan receivable	0	0
Other assets	171.2	259.7
Total Assets	15,280.9	15,206.3
Current Liabilities:
Current maturities of long-term debt	313.7	271.2
Accounts payable	113.3	112.1
Accrued payroll and payroll-related costs	98.5	76.1
Interest Payable, Current	57	68.7
Taxes Payable, Current	15.8	101.7
Accrued and other current liabilities	452.1	557.1
Current liabilities held for sale	0	120.3
Intercompany payable	0	0
Total current liabilities	1,050.4	1,307.2
Long-term debt	6,420.9	5,880.8
Pension and postretirement benefits	67.1	136.4
Environmental liabilities	73.2	73
Deferred income taxes	689	2,398.1
Other income tax liabilities	94.1	70.4
Long-term liabilities held for sale	0	0
Intercompany loans payable	0	0
Other liabilities	364.2	356.1
Total Liabilities	8,758.9	10,222
Shareholders' equity	6,522	4,984.3	5,270.7		5,311.2	$ 4,958
Total Liabilities and Shareholders' Equity	15,280.9	15,206.3
Mallinckrodt plc
Current Assets:
Cash and cash equivalents	0.7	0.5	0.3		0.1
Accounts receivable, net	0	0
Inventories	0	0
Deferred income taxes	0	0
Prepaid expenses and other current assets	1	1
Notes, Loans and Financing Receivable, Net, Current	0	0
Current assets held for sale	0	0
Intercompany receivable	70	59.7
Total current assets	71.7	61.2
Property, plant and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Long-term assets held for sale	0	0
Investment in subsidiaries	6,551.6	5,534.1
Intercompany loan receivable	593.1	3.5
Other assets	0	0
Total Assets	7,216.4	5,598.8
Current Liabilities:
Current maturities of long-term debt	0	0
Accounts payable	0.1	0.1
Accrued payroll and payroll-related costs	0	0
Interest Payable, Current	0	0
Taxes Payable, Current	0	0
Accrued and other current liabilities	0.8	1.9
Current liabilities held for sale	0	0
Intercompany payable	693.5	612.5
Total current liabilities	694.4	614.5
Long-term debt	0	0
Pension and postretirement benefits	0	0
Environmental liabilities	0	0
Deferred income taxes	0	0
Other income tax liabilities	0	0
Long-term liabilities held for sale	0	0
Intercompany loans payable	0	0
Other liabilities	0	0
Total Liabilities	694.4	614.5
Shareholders' equity	6,522	4,984.3
Total Liabilities and Shareholders' Equity	7,216.4	5,598.8
Mallinckrodt International Finance S.A.
Current Assets:
Cash and cash equivalents	908.8	44.5	25		152.1
Accounts receivable, net	0	0
Inventories	0	0
Deferred income taxes	0	0
Prepaid expenses and other current assets	0.2	0
Notes, Loans and Financing Receivable, Net, Current	0	0
Current assets held for sale	0	0
Intercompany receivable	173.4	65.1
Total current assets	1,082.4	109.6
Property, plant and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Long-term assets held for sale	0	0
Investment in subsidiaries	23,217.8	20,624.1
Intercompany loan receivable	0	0
Other assets	0	0
Total Assets	24,300.2	20,733.7
Current Liabilities:
Current maturities of long-term debt	313.5	19.7
Accounts payable	0	0.1
Accrued payroll and payroll-related costs	0	0
Interest Payable, Current	53	53.9
Taxes Payable, Current	0	0
Accrued and other current liabilities	0.4	7.5
Current liabilities held for sale	0	0
Intercompany payable	104.6	467.1
Total current liabilities	471.5	548.3
Long-term debt	6,206.8	5,860.6
Pension and postretirement benefits	0	0
Environmental liabilities	0	0
Deferred income taxes	0	0
Other income tax liabilities	0	0
Long-term liabilities held for sale	0	0
Intercompany loans payable	5,257.9	3,329.4
Other liabilities	7.8	7
Total Liabilities	11,944	9,745.3
Shareholders' equity	12,356.2	10,988.4
Total Liabilities and Shareholders' Equity	24,300.2	20,733.7
Other Subsidiaries
Current Assets:
Cash and cash equivalents	351.4	297	255.2		213.7
Accounts receivable, net	445.8	431
Inventories	340.4	350.7
Deferred income taxes	0	0
Prepaid expenses and other current assets	82.9	130.9
Notes, Loans and Financing Receivable, Net, Current	154	0
Current assets held for sale		310.9
Intercompany receivable	831.4	1,081.3
Total current assets	2,205.9	2,601.8
Property, plant and equipment, net	966.8	881.5
Goodwill	3,482.7	3,498.1
Intangible assets, net	8,375	9,000.5
Long-term assets held for sale	0	0
Investment in subsidiaries	12,356.2	10,988.5
Intercompany loan receivable	4,664.8	3,325.9
Other assets	171.2	259.7
Total Assets	32,222.6	30,556
Current Liabilities:
Current maturities of long-term debt	0.2	251.5
Accounts payable	113.2	111.9
Accrued payroll and payroll-related costs	98.5	76.1
Interest Payable, Current	4	14.8
Taxes Payable, Current	15.8	101.7
Accrued and other current liabilities	450.9	547.7
Current liabilities held for sale	0	120.3
Intercompany payable	276.7	126.5
Total current liabilities	959.3	1,350.5
Long-term debt	214.1	20.2
Pension and postretirement benefits	67.1	136.4
Environmental liabilities	73.2	73
Deferred income taxes	689	2,398.1
Other income tax liabilities	94.1	70.4
Long-term liabilities held for sale	0	0
Intercompany loans payable	0	0
Other liabilities	356.4	349.1
Total Liabilities	2,453.2	4,397.7
Shareholders' equity	29,769.4	26,158.3
Total Liabilities and Shareholders' Equity	32,222.6	30,556
Eliminations
Current Assets:
Cash and cash equivalents	0	0	$ 0		$ 0
Accounts receivable, net	0	0
Inventories	0	0
Deferred income taxes	0	0
Prepaid expenses and other current assets	0	0
Notes, Loans and Financing Receivable, Net, Current	0	0
Current assets held for sale	0	0
Intercompany receivable	(1,074.8)	(1,206.1)
Total current assets	(1,074.8)	(1,206.1)
Property, plant and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Long-term assets held for sale	0	0
Investment in subsidiaries	(42,125.6)	(37,146.7)
Intercompany loan receivable	(5,257.9)	(3,329.4)
Other assets	0	0
Total Assets	(48,458.3)	(41,682.2)
Current Liabilities:
Current maturities of long-term debt	0	0
Accounts payable	0	0
Accrued payroll and payroll-related costs	0	0
Interest Payable, Current	0	0
Taxes Payable, Current	0	0
Accrued and other current liabilities	0	0
Current liabilities held for sale	0	0
Intercompany payable	(1,074.8)	(1,206.1)
Total current liabilities	(1,074.8)	(1,206.1)
Long-term debt	0	0
Pension and postretirement benefits	0	0
Environmental liabilities	0	0
Deferred income taxes	0	0
Other income tax liabilities	0	0
Long-term liabilities held for sale	0	0
Intercompany loans payable	(5,257.9)	(3,329.4)
Other liabilities	0	0
Total Liabilities	(6,332.7)	(4,535.5)
Shareholders' equity	(42,125.6)	(37,146.7)
Total Liabilities and Shareholders' Equity	$ (48,458.3)	$ (41,682.2)

Condensed Consolidating and 138

Condensed Consolidating and Combining Financial Statements (Schedule of Condensed Consolidating and Combining Statements of Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended									12 Months Ended
	Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 30, 2016	Sep. 30, 2016	Jun. 24, 2016	Mar. 25, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Condensed Consolidating Financial Statements
Net sales	$ 792.3	$ 793.9	$ 824.5	$ 810.9	$ 829.9	$ 887.2	$ 866.6	$ 815.8	$ 811.2	$ 3,221.6	$ 3,380.8	$ 2,923.1
Cost of sales					384.1				360.3	1,565.3	1,525.8	1,300.2
Gross profit	421	400.6	416.1	418.6	445.8	490.2	488.8	425.1	450.9	1,656.3	1,855	1,622.9
Selling, general and administrative expenses					368.3				223.3	920.9	925.3	1,023.8
Research and development expenses					66.2				61.4	277.3	262.2	203.3
Separation costs					0					0	0	0
Restructuring charges, net					3.8				4.1	31.2	33.3	45
Non-restructuring impairment charges					214.3					63.7	16.9	0
Gain on divestiture and license					0					(56.9)	0	(3)
Operating income (loss)					(206.8)				(162.1)	420.1	617.3	353.8
Interest expense					(91.3)				(97.8)	(369.1)	(384.6)	(255.6)
Interest income					0.5				0.2	4.6	1.3	1
Other income (expense), net					(0.9)				2	6	(0.6)	8.1
Intercompany interest and fees					0					0	0	0
Equity in net income of subsidiaries					0					0	0	0
Income (loss) from continuing operations before income taxes					(298.5)				66.5	61.6	233.4	107.3
Income Tax Expense (Benefit)					(121.7)				(37.3)	(1,709.6)	(255.6)	(129.3)
Income (loss) from continuing operations	1,607.4	64.3	70.6	28.9	(176.8)	110	176.7	98.5	103.8	1,771.2	489	236.6
Income (loss) from discontinued operations, net of income taxes	1.3	(0.6)	(7.8)	370.3	23.6	5	22.6	19.8	107.3	363.2	154.7	88.1
Net income (loss)	$ 1,608.7	$ 63.7	$ 62.8	$ 399.2	(153.2)	$ 115	$ 199.3	$ 118.3	$ 211.1	2,134.4	643.7	324.7
Other comprehensive loss, net of tax					13.1					59.6	(86.5)	(64.8)
Comprehensive income (loss)					(140.1)					2,194	557.2	259.9
Mallinckrodt plc
Condensed Consolidating Financial Statements
Net sales					0					0	0	0
Cost of sales					0					2.6	0	0
Gross profit					0					(2.6)	0	0
Selling, general and administrative expenses					13.4					59.5	51.3	116.3
Research and development expenses					0					5.1	0	0
Separation costs					0					0	0	0
Restructuring charges, net					0					0	0	9.8
Non-restructuring impairment charges					0					0	0	0
Gain on divestiture and license					0					0	0	0
Operating income (loss)					(13.4)					(67.2)	(51.3)	(126.1)
Interest expense					(2.9)					(13.8)	(230.3)	96.4
Interest income					0					7.3	0	0
Other income (expense), net					1.8					20.3	90	216.3
Intercompany interest and fees					4.4					18.3	16.1	14.7
Equity in net income of subsidiaries					(136.5)					2,200	820.8	330.6
Income (loss) from continuing operations before income taxes					(155.4)					2,128.3	613.1	309.7
Income Tax Expense (Benefit)					(2.2)					(6.1)	(30.6)	(15.9)
Income (loss) from continuing operations					(153.2)					2,134.4	643.7	325.6
Income (loss) from discontinued operations, net of income taxes					0					0	0	(0.9)
Net income (loss)					(153.2)					2,134.4	643.7	324.7
Other comprehensive loss, net of tax					13.1					59.6	(86.5)	(64.8)
Comprehensive income (loss)					(140.1)					2,194	557.2	259.9
Mallinckrodt International Finance S.A.
Condensed Consolidating Financial Statements
Net sales					0					0	0	0
Cost of sales					0					0	0	0
Gross profit					0					0	0	0
Selling, general and administrative expenses					0.2					0.7	0.8	15.7
Research and development expenses					0					0	0	0
Separation costs					0					0	0	0
Restructuring charges, net					0					0	0	0
Non-restructuring impairment charges					0					0	0	0
Gain on divestiture and license					0					0	0	0
Operating income (loss)					(0.2)					(0.7)	(0.8)	(15.7)
Interest expense					(81.1)					(353.9)	(327)	(230.2)
Interest income					0.1					1.2	0.5	0.1
Other income (expense), net					0.7					(1.7)	1.7	0
Intercompany interest and fees					0					0	0	0
Equity in net income of subsidiaries					35.2					2,901.8	1,327.2	496.3
Income (loss) from continuing operations before income taxes					(45.3)					2,546.7	1,001.6	250.5
Income Tax Expense (Benefit)					(0.3)					(5.3)	(18.1)	0
Income (loss) from continuing operations					(45)					2,552	1,019.7	250.5
Income (loss) from discontinued operations, net of income taxes					0.4					(2.1)	38.2	0
Net income (loss)					(44.6)					2,549.9	1,057.9	250.5
Other comprehensive loss, net of tax					13.1					59.6	(86.5)	(64.8)
Comprehensive income (loss)					(31.5)					2,609.5	971.4	185.7
Other Subsidiaries
Condensed Consolidating Financial Statements
Net sales					829.9					3,221.6	3,380.8	2,923.1
Cost of sales					384.1					1,562.7	1,525.8	1,300.2
Gross profit					445.8					1,658.9	1,855	1,622.9
Selling, general and administrative expenses					354.7					860.7	873.2	891.8
Research and development expenses					66.2					272.2	262.2	203.3
Separation costs					0					0	0	0
Restructuring charges, net					3.8					31.2	33.3	35.2
Non-restructuring impairment charges					214.3					63.7	16.9	0
Gain on divestiture and license					0					(56.9)	0	(3)
Operating income (loss)					(193.2)					488	669.4	495.6
Interest expense					(17.9)					(74.2)	(82.4)	(25.2)
Interest income					11					68.9	255.9	97.1
Other income (expense), net					(3.4)					(12.6)	(92.3)	(208.2)
Intercompany interest and fees					(4.4)					(18.3)	(16.1)	(14.7)
Equity in net income of subsidiaries					(44.5)					2,549.9	1,057.9	250.5
Income (loss) from continuing operations before income taxes					(243.6)					3,038.3	1,824.6	624.5
Income Tax Expense (Benefit)					(119.2)					(1,698.2)	(206.9)	(113.4)
Income (loss) from continuing operations					(124.4)					4,736.5	2,031.5	737.9
Income (loss) from discontinued operations, net of income taxes					23.2					365.3	116.5	89
Net income (loss)					(101.2)					5,101.8	2,148	826.9
Other comprehensive loss, net of tax					26					118.2	(173.5)	(69.9)
Comprehensive income (loss)					(75.2)					5,220	1,974.5	757
Eliminations
Condensed Consolidating Financial Statements
Net sales					0					0	0	0
Cost of sales					0					0	0	0
Gross profit					0					0	0	0
Selling, general and administrative expenses					0					0	0	0
Research and development expenses					0					0	0	0
Separation costs					0					0	0	0
Restructuring charges, net					0					0	0	0
Non-restructuring impairment charges					0					0	0	0
Gain on divestiture and license					0					0	0	0
Operating income (loss)					0					0	0	0
Interest expense					10.6					72.8	255.1	96.2
Interest income					(10.6)					(72.8)	(255.1)	(96.2)
Other income (expense), net					0					0	0	0
Intercompany interest and fees					0					0	0	0
Equity in net income of subsidiaries					145.8					(7,651.7)	(3,205.9)	(1,077.4)
Income (loss) from continuing operations before income taxes					145.8					(7,651.7)	(3,205.9)	(1,077.4)
Income Tax Expense (Benefit)					0					0	0	0
Income (loss) from continuing operations					145.8					(7,651.7)	(3,205.9)	(1,077.4)
Income (loss) from discontinued operations, net of income taxes					0					0	0	0
Net income (loss)					145.8					(7,651.7)	(3,205.9)	(1,077.4)
Other comprehensive loss, net of tax					(39.1)					(177.8)	260	134.7
Comprehensive income (loss)					$ 106.7					$ (7,829.5)	$ (2,945.9)	$ (942.7)

Condensed Consolidating and 139

Condensed Consolidating and Combining Financial Statements (Schedule of Condensed Consolidating and Combining Statements of Cash Flows) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 30, 2016	Dec. 25, 2015	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014
Condensed Consolidating Financial Statements
Restricted Cash and Investments, Current	$ 0.1	$ 47.5	$ 0	$ 0.1	$ 47.7
Cash Flows From Operating Activities:
Net cash (used in) provided by operating activities	195.6	311.4	727.3	1,184.6	930.5
Cash Flows From Investing Activities:
Capital expenditures	(65.2)	(49)	(186.1)	(182.9)	(148)
Acquisitions and intangibles, net of cash acquired	(1.8)	0	(76.3)	(245.4)	(2,154.7)
Proceeds from Divestiture of Businesses, Net of Cash Divested	0	263.7	576.9	266.7	0
Intercompany Loan Investment	0		0	0	0
Subsidiary dividend proceeds	0		0		0
Investment in subsidiary	0		0	0	0
Proceeds from Divestiture of Subsidiary			0	0
Payments to Acquire Subsidiary			0	0
Restricted cash			0
Other	(10.2)	(0.7)	3.9	6	3
Net cash from investing activities	(77.2)	215.4	318.4	(155.6)	(2,299.7)
Cash Flows From Financing Activities:
Issuance of external debt	190	62	1,465	98.3	3,010
Repayment of capital leases	(86.7)	(129.6)	(917.2)	(568.6)	(1,848.4)
Debt financing costs	0	(0.1)	(12.7)	(0.1)	(39.9)
Proceeds from exercise of share options	0.4	3.6	4.1	14	34.4
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	0				0
Intercompany loan borrowings	0		0	0	0
Capital contribution	0		0	0	0
Repurchase of shares	(158.8)	(275.4)	(651.7)	(652.9)	(92.2)
Other	1.2	(30)	(17.7)	(53)	(28.1)
Net cash provided by financing activities	(53.9)	(369.5)	(130.2)	(1,162.3)	1,035.8
Effect of currency rate changes on cash	(3)	(1.5)	2.5	0.3	(11.6)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	61.5	155.8	918	(133)	(345)
Cash and cash equivalents	342	521.9	1,260.9	280.5	365.9
Restricted Cash and Investments, Noncurrent	19	19	18.2	19	19
Cash and Cash Equivalents, Including Restricted Cash	361.1	$ 588.4	1,279.1	299.6	432.6	$ 777.6
Mallinckrodt plc
Condensed Consolidating Financial Statements
Net Cash Provided by (Used in) Operating Activities	17.4
Restricted Cash and Investments, Current	0		0	0	0
Cash Flows From Operating Activities:
Net cash (used in) provided by operating activities			1,233.2	17.9	207
Cash Flows From Investing Activities:
Capital expenditures	0		0	0	0
Acquisitions and intangibles, net of cash acquired	0		0	0	0
Proceeds from Divestiture of Businesses, Net of Cash Divested			0	0
Intercompany Loan Investment	0		(589.5)	0	(149.4)
Subsidiary dividend proceeds	0		0		0
Investment in subsidiary	0		0	0	0
Proceeds from Divestiture of Subsidiary			0	3.4
Payments to Acquire Subsidiary			0	0
Restricted cash			0
Other	0		0	0	0
Net cash from investing activities	0		(589.5)	3.4	(149.4)
Cash Flows From Financing Activities:
Issuance of external debt	0		0	0	0
Repayment of capital leases	0		0	0	0
Debt financing costs	0		0	0	0
Proceeds from exercise of share options	0.4		4.1	14	34.4
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	0				0
Intercompany loan borrowings	(140)		0	(617.8)	0
Capital contribution	0		0	0	0
Repurchase of shares	158.8		651.7	652.9	(92.2)
Other	1.2		4.1	0	0
Net cash provided by financing activities	(17.2)		(643.5)	(21.1)	(57.8)
Effect of currency rate changes on cash	0		0	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	0.2		0.2	0.2	(0.2)
Cash and cash equivalents	0.5		0.7	0.3	0.1
Restricted Cash and Investments, Noncurrent	0		0	0	0
Cash and Cash Equivalents, Including Restricted Cash	0.5		0.7	0.3	0.1	0.3
Mallinckrodt International Finance S.A.
Condensed Consolidating Financial Statements
Restricted Cash and Investments, Current	0		0	0	0
Cash Flows From Operating Activities:
Net cash (used in) provided by operating activities	(94)		1,139.4	(47.4)	(148.2)
Cash Flows From Investing Activities:
Capital expenditures	0		0	0	0
Acquisitions and intangibles, net of cash acquired	0		0	0	0
Proceeds from Divestiture of Businesses, Net of Cash Divested			0	234
Intercompany Loan Investment	0		0	(175.2)	0
Subsidiary dividend proceeds	0		(1,170)		0
Investment in subsidiary	260		(1,475.3)	(861.2)	(3,014.4)
Proceeds from Divestiture of Subsidiary			0	0
Payments to Acquire Subsidiary			0	0
Restricted cash			0
Other	0		0	0	0
Net cash from investing activities	(260)		(1,475.3)	(802.4)	(3,014.4)
Cash Flows From Financing Activities:
Issuance of external debt	175		1,400	0	2,890
Repayment of capital leases	86.2		(764.5)	(549.2)	(258.3)
Debt financing costs	0		(12.7)	0	(39.1)
Proceeds from exercise of share options	0		0	0	0
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	0				0
Intercompany loan borrowings	(284.7)		(1,747.4)	(1,271.9)	(703.6)
Capital contribution	0		0	0	0
Repurchase of shares	0		0	0	0
Other	0		0	0	0
Net cash provided by financing activities	373.5		1,200.2	722.7	3,296.2
Effect of currency rate changes on cash	0		0	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	19.5		864.3	(127.1)	133.6
Cash and cash equivalents	44.5		908.8	25	152.1
Restricted Cash and Investments, Noncurrent	0		0	0	0
Cash and Cash Equivalents, Including Restricted Cash	44.5		908.8	25	152.1	18.5
Other Subsidiaries
Condensed Consolidating Financial Statements
Restricted Cash and Investments, Current	0.1		0	0.1	47.7
Cash Flows From Operating Activities:
Net cash (used in) provided by operating activities	272.2		2,274.9	1,214.1	871.7
Cash Flows From Investing Activities:
Capital expenditures	65.2		(186.1)	(182.9)	(148)
Acquisitions and intangibles, net of cash acquired	(1.8)		(76.3)	(245.4)	(2,154.7)
Proceeds from Divestiture of Businesses, Net of Cash Divested			576.9	32.7
Intercompany Loan Investment	(424.7)		(1,157.9)	(1,714.5)	(554.2)
Subsidiary dividend proceeds	0		(2,750.2)		0
Investment in subsidiary	0		0	0	0
Proceeds from Divestiture of Subsidiary			0	0
Payments to Acquire Subsidiary			0	(3.4)
Restricted cash			0
Other	10.2		3.9	6	3
Net cash from investing activities	(501.9)		(839.5)	(2,107.5)	(2,853.9)
Cash Flows From Financing Activities:
Issuance of external debt	15		65	98.3	120
Repayment of capital leases	0.5		(152.7)	(19.4)	(1,590.1)
Debt financing costs	0		0	(0.1)	(0.8)
Proceeds from exercise of share options	0		0	0	0
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	0				0
Intercompany loan borrowings	0		0	0	0
Capital contribution	260		1,475.3	861.2	3,014.4
Repurchase of shares	0		0	0	0
Other	0		(21.8)	(53)	(28.1)
Net cash provided by financing activities	274.5		(1,384.4)	887	1,515.4
Effect of currency rate changes on cash	(3)		2.5	0.3	(11.6)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	41.8		53.5	(6.1)	(478.4)
Cash and cash equivalents	297		351.4	255.2	213.7
Restricted Cash and Investments, Noncurrent	19		18.2	19	19
Cash and Cash Equivalents, Including Restricted Cash	316.1		369.6	274.3	280.4	758.8
Eliminations
Condensed Consolidating Financial Statements
Restricted Cash and Investments, Current	0		0	0	0
Cash Flows From Operating Activities:
Net cash (used in) provided by operating activities	0		(3,920.2)	0	0
Cash Flows From Investing Activities:
Capital expenditures	0		0	0	0
Acquisitions and intangibles, net of cash acquired	0		0	0	0
Proceeds from Divestiture of Businesses, Net of Cash Divested			0	0
Intercompany Loan Investment	(424.7)		(1,747.4)	(1,889.7)	(703.6)
Subsidiary dividend proceeds	0		(3,920.2)		0
Investment in subsidiary	(260)		1,475.3	861.2	3,014.4
Proceeds from Divestiture of Subsidiary			0	(3.4)
Payments to Acquire Subsidiary			0	3.4
Restricted cash			0
Other	0		0	0	0
Net cash from investing activities	684.7		3,222.7	2,750.9	3,718
Cash Flows From Financing Activities:
Issuance of external debt	0		0	0	0
Repayment of capital leases	0		0	0	0
Debt financing costs	0		0	0	0
Proceeds from exercise of share options	0		0	0	0
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	0				0
Intercompany loan borrowings	424.7		1,747.4	1,889.7	703.6
Capital contribution	(260)		(1,475.3)	(861.2)	(3,014.4)
Repurchase of shares	0		0	0	0
Other	0		0	0	0
Net cash provided by financing activities	(684.7)		697.5	(2,750.9)	(3,718)
Effect of currency rate changes on cash	0		0	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	0		0	0	0
Cash and cash equivalents	0		0	0	0
Restricted Cash and Investments, Noncurrent	0		0	0	0
Cash and Cash Equivalents, Including Restricted Cash	$ 0		$ 0	$ 0	$ 0	$ 0

Subsequent Events (Details)

Subsequent Events (Details) - USD ($)	Feb. 27, 2018	Feb. 21, 2018	Feb. 13, 2018	Jan. 16, 2018	Jul. 28, 2017	Feb. 28, 2017	Jan. 08, 2018	Dec. 29, 2017	Dec. 30, 2016
Subsequent Event [Line Items]
Long-term Debt, Gross								$ 6,492,600,000	$ 5,965,800,000
Debt Conversion, Converted Instrument, Amount			$ 1,221
Hemostasis Products | Subsequent Event [Member]
Subsequent Event [Line Items]
Consideration							$ 185,000,000
Disposal Group, Including Discontinued Operation, Upfront Consideration							$ 153,000,000
Sucampo [Member]
Subsequent Event [Line Items]
Business Acquisition, Transaction Costs								4,200,000
Sucampo [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Total consideration			1,200,000,000
Term Loan due 2025 [Member] | Secured Debt | Sucampo [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Long term debt			$ 600,000,000
Variable interest rate			30000.00%
Debt instrument, discount percentage			2500.00%
2015 Revolving Credit Facility | Debentures
Subsequent Event [Line Items]
Long-term Debt, Gross								900,000,000	100,000,000
Sucampo 2021 Notes [Member] | Convertible Debt Securities [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Long-term Debt, Gross			$ 300,000,000
Stated interest rate			3.25%
Debt Conversion, Converted Instrument, Amount	$ 73,500,000
Debt instrument, face amount			$ 1,000
Term Loan due Sept 2024 [Member]
Subsequent Event [Line Items]
Long-term Debt, Gross								1,851,200,000
Term Loan due Sept 2024 [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Repayments of Long-term Debt				$ 225,000,000
Term Loan due Sept 2024 [Member] | Secured Debt
Subsequent Event [Line Items]
Long-term Debt, Gross								1,837,200,000	0
Receivable securitization, Maturity Date of July 2020 [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Long-term Debt, Gross		$ 225,000,000
Proceeds from Lines of Credit		25,000,000
Receivable securitization, Maturity Date of July 2020 [Member] | Secured Debt
Subsequent Event [Line Items]
Variable interest rate					0.90%
Long-term Debt, Gross								200,000,000	$ 0
2017 Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Long-term Debt, Gross		625,000,000
Repayments of Debt		$ 275,000,000
2017 Revolving Credit Facility [Member] | Debentures
Subsequent Event [Line Items]
Variable interest rate						2.25%
Long-term Debt, Gross								$ 900,000,000

Schedule II - Valuation and 141

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 30, 2016	Dec. 29, 2017	Sep. 30, 2016	Sep. 25, 2015
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 4	$ 4	$ 3.6	$ 2.2
Charged to Income	0.1	0.6	0.3	1.2
Additions and Other	0	0	0	0
Deductions	(0.1)	(0.7)	(0.1)	0.2
Balance at End of Period	4	3.9	4	3.6
Sales reserve accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	378	391.3	396.4	402.2
Charged to Income	515.3	2,008.5	2,030.8	2,177.4
Additions and Other	0	0	0	1.3
Deductions	(502)	(2,023.2)	(2,049.2)	(2,184.5)
Balance at End of Period	391.3	376.6	378	396.4
Tax valuation allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	564.9	1,398.3	233	76.9
Charged to Income	833.4	804.6	315.7	155.4
Additions and Other	0	4	15.8	0.2
Deductions	0	(61)	0.4	0.5
Balance at End of Period	$ 1,398.3	$ 2,267.9	$ 564.9	$ 233