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	421.0		400.6		416.1		418.6		445.8	490.2		488.8		425.1		450.9		1,656.3	1,855.0	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	0.0	0.0
Other Asset Impairment Charges									214.3							0.0		63.7	16.9	0.0
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal									0.0									(56.9)	0.0	(3.0)
Restructuring charges, net									3.8							4.1		31.2	33.3	45.0
Non-restructuring impairment charges									214.3									63.7	16.9	0.0
Gain on divestiture and license									0.0									(56.9)	0.0	(3.0)
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	1.0
Other income (expense), net									(0.9)							2.0		6.0	(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)	110.0		176.7		98.5		103.8		1,771.2	489.0	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	5.0		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)	$ 115.0		$ 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	$ 2.00
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.