CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Jul. 02, 2017	Jul. 03, 2016	Jul. 02, 2017	Jul. 03, 2016
Income Statement [Abstract]
Net sales	$ 458.1	$ 431.4	$ 1,336.5	$ 1,204.9
Cost of sales	165.4	164.5	483.2	549.6
Gross profit	292.7	266.9	853.3	655.3
Operating expenses:
Selling, general and administrative	76.8	82.9	243.1	265.8
Research and development costs	85.1	83.0	254.3	225.7
Amortization of intangible assets	49.6	44.9	141.6	115.6
Restructuring and severance charges	11.2	4.9	19.4	58.3
Total operating expenses	222.7	215.7	658.4	665.4
Operating income	70.0	51.2	194.9	(10.1)
Other income (expense)
Interest expense, net	(23.5)	(46.8)	(75.4)	(93.0)
Other expense, net	(35.2)	(5.3)	(35.5)	(83.7)
Gain (loss) on divestiture	0.0	125.5	(1.2)	125.5
Total other income (expense)	(58.7)	73.4	(112.1)	(51.2)
Income (loss) before income taxes	11.3	124.6	82.8	(61.3)
Provision for (benefit from) income taxes	(2.3)	9.4	8.5	11.8
Net income (loss)	$ 13.6	$ 115.2	$ 74.3	$ (73.1)
Earnings (loss) per share
Basic (USD per share)	$ 0.12	$ 1.03	$ 0.65	$ (0.69)
Diluted (USD per share)	$ 0.12	$ 1.00	$ 0.64	$ (0.69)
Weighted-average common shares outstanding:
Basic (in shares)	115.0	112.1	114.7	105.3
Diluted (in shares)	117.2	114.6	116.8	105.3
Net income (loss)	$ 13.6	$ 115.2	$ 74.3	$ (73.1)
Other comprehensive income, net of taxes
Translation adjustment	1.0	0.2	0.1	2.8
Unrealized actuarial loss on pension benefits	0.0	(0.1)	(0.1)	(0.2)
Other comprehensive income, net of taxes	1.0	0.1	0.0	2.6
Total comprehensive income (loss)	$ 14.6	$ 115.3	$ 74.3	$ (70.5)