Consolidated Statements Of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 27, 2020	Mar. 29, 2019	Mar. 27, 2020	Mar. 29, 2019
Income Statement [Abstract]
Document Period End Date			Mar. 27, 2020
Net revenue	$ 766.1	$ 810.4	$ 1,662.2	$ 1,782.4
Cost of goods sold	390.5	410.2	842.3	897.0
Gross profit	375.6	400.2	819.9	885.4
Operating expenses:
Research and development	113.2	107.5	220.8	216.7
Selling, general and administrative	58.6	47.9	114.0	95.7
Amortization of intangibles	3.1	5.7	6.3	13.1
Restructuring and other charges	1.2	1.5	2.0	1.4
Total operating expenses	176.1	162.6	343.1	326.9
Operating income	199.5	237.6	476.8	558.5
Other income, net	3.5	3.7	4.9	6.6
Income before income taxes	203.0	241.3	481.7	565.1
Provision for income taxes	21.9	27.3	43.6	66.3
Net income	$ 181.1	$ 214.0	$ 438.1	$ 498.8
Earnings per share:
Basic (in dollars per share)	$ 1.07	$ 1.23	$ 2.58	$ 2.85
Diluted (in dollars per share)	$ 1.06	$ 1.23	$ 2.56	$ 2.83
Weighted average shares:
Basic (in shares)	170.0	173.8	170.1	175.2
Diluted (in shares)	171.1	174.6	171.3	176.1
Common Stock, Dividends, Per Share, Declared	$ 0.44	$ 0.38	$ 0.88	$ 0.76