Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Sep. 27, 2015
Income Statement [Abstract]
Net sales	$ 1,811.8	$ 1,655.0	$ 1,245.6
Cost of sales	654.3	717.9	561.3
Gross profit	1,157.5	937.1	684.3
Operating expenses:
Selling, general and administrative	330.7	352.4	249.5
Research and development costs	341.6	309.1	200.3
Amortization of intangible assets	191.7	161.2	96.5
Restructuring and severance charges	23.2	60.7	15.4
Total operating expenses	887.2	883.4	561.7
Operating income	270.3	53.7	122.6
Interest Income (Expense), Net	(97.7)	(120.1)	(27.3)
Other income (expenses):
Other, net	(36.5)	41.0	1.6
Total other expense	(134.2)	(79.1)	(25.7)
Income (loss) before income taxes	136.1	(25.4)	96.9
Income Tax Expense (Benefit)	(40.2)	7.2	12.3
Net income (loss)	$ 176.3	$ (32.6)	$ 84.6
Earnings (loss) per share:
Basic	$ 1.54	$ (0.31)	$ 0.90
Diluted	$ 1.51	$ (0.31)	$ 0.88
Weighted-average common shares outstanding:
Basic	114.9	107.0	94.2
Diluted	117.1	107.0	95.9
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Translation adjustment	$ 2.7	$ 4.8	$ (1.6)
Unrealized actuarial loss on pension benefits	(0.1)	(3.9)	(0.3)
Other comprehensive income (loss)	2.6	0.9	(1.9)
Total comprehensive income (loss)	$ 178.9	$ (31.7)	$ 82.7