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	421.0		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
Restructuring Charges									3.8							4.1		31.2	33.3	45.0
Other Asset Impairment Charges									214.3							0.0		63.7	16.9	0.0
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
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)	110.0		176.7		98.5		103.8		1,771.2	489.0	236.6
Income (loss) from discontinued operations, net of income taxes	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
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	$ 2.00
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.