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.