Employee Stock Award and Benefit Plans - Employee Retirement and Investment and Stock Purchase Plans (Details) - USD ($) $ in Millions	12 Months Ended
Oct. 03, 2020	Sep. 28, 2019	Sep. 29, 2018
Share-based Payment Arrangement [Abstract]
Postretirement benefit plan, maximum employer contribution rate	4.00%
Employer contributions to retirement and investment plans net of forfeitures	$ 6.1	$ 5.7	$ 5.6

Amount of cash outflow for other postretirement benefit. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree. Excludes pension benefit.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3536-108585

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration