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		0.0
Separation costs						0.0						0.0	0.0		0.0
Assets		$ 15,280.9				15,206.3						15,280.9
Depreciation and amortization						203.2					$ 206.0	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]					816.0						3,164.8	3,325.8		2,874.4
Operating income (loss)						369.9						1,386.7	1,542.3		1,232.0
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	55.0	[4]	48.7	[4]
Corporate and allocated expenses	[5]					(181.4)						(172.0)	(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)		$ 0.0
Intersegment Eliminations
Segment Reporting Information [Line Items]
Net sales												$ 0.0					$ 0.0	$ 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.