Employee Stock Award and Benefit Plans - Employee Retirement and Investment and Stock Purchase Plans (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 29, 2018	Sep. 30, 2017	Oct. 01, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Postretirement benefit plan, maximum employer contribution rate	4.00%
Employer contributions to retirement and investment plans net of forfeitures	$ 5.6	$ 4.8	$ 4.1

Amount of payment for other postretirement benefits. Excludes pension benefits.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3536-108585

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration