Consolidated Statements Of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Dec. 27, 2019	Dec. 28, 2018
Income Statement [Abstract]
Document Period End Date	Dec. 27, 2019
Net revenue	$ 896.1	$ 972.0
Cost of goods sold	451.8	486.9
Gross profit	444.3	485.1
Operating expenses:
Research and development	107.7	109.2
Selling, general and administrative	55.4	47.8
Amortization of intangibles	3.1	7.4
Restructuring and other charges (benefit)	0.8	(0.2)
Total operating expenses	167.0	164.2
Operating income	277.3	320.9
Other income, net	1.4	2.9
Income before income taxes	278.7	323.8
Provision for income taxes	21.6	38.9
Net income	$ 257.1	$ 284.9
Earnings per share:
Basic (in dollars per share)	$ 1.51	$ 1.61
Diluted (in dollars per share)	$ 1.50	$ 1.60
Weighted average shares:
Basic (in shares)	170.2	176.6
Diluted (in shares)	171.6	177.7
Common Stock, Dividends, Per Share, Declared	$ 0.44	$ 0.38