Consolidated Balance Sheets - USD ($) $ in Millions	6 Months Ended
	Mar. 27, 2020	Sep. 27, 2019
Statement of Financial Position [Abstract]
Document Period End Date	Mar. 27, 2020
Current assets:
Cash and cash equivalents	$ 912.4	$ 851.3
Marketable Securities, Current	161.5	203.3
Receivables, net of allowance of $0.8 and $0.8, respectively	367.6	465.3
Inventory	648.9	609.7
Other current assets	130.4	105.0
Total current assets	2,220.8	2,234.6
Property, plant and equipment, net	1,207.9	1,205.6
Operating Lease, Right-of-Use Asset	171.3	0.0
Goodwill	1,189.8	1,189.8
Intangible assets, net	85.4	107.9
Deferred Income Tax Assets, Net	39.6	40.8
Marketable Securities, Noncurrent	34.1	27.6
Other long-term assets	33.0	33.3
Total assets	4,981.9	4,839.6
Current liabilities:
Accounts payable	169.5	190.5
Accrued compensation and benefits	78.4	76.0
Other current liabilities	114.3	107.5
Total current liabilities	362.2	374.0
Long-term tax liabilities	293.0	312.4
Operating Lease, Liability, Noncurrent	151.9	0.0
Other long-term liabilities	32.0	30.9
Total liabilities	839.1	717.3
Stockholders’ equity:
Preferred stock, no par value: 25.0 shares authorized, no shares issued	0.0	0.0
Common stock, $0.25 par value: 525.0 shares authorized; 231.9 shares issued and 167.5 shares outstanding at March 27, 2020, and 230.2 shares issued and 170.1 shares outstanding at September 27, 2019	41.9	42.5
Additional paid-in capital	3,307.2	3,188.0
Treasury stock, at cost	(3,799.6)	(3,412.9)
Retained earnings	4,600.8	4,312.6
Accumulated other comprehensive loss	(7.5)	(7.9)
Total stockholders’ equity	4,142.8	4,122.3
Total liabilities and stockholders’ equity	$ 4,981.9	$ 4,839.6