Restructuring and Impairment Charges - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Dec. 29, 2018	Dec. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Oct. 01, 2016
Restructuring and Related Activities [Abstract]
Restructuring and impairment charges	$ 0	$ 15	$ 33	$ 98	$ 156

Amount of restructuring charges, remediation cost, and asset impairment loss.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.3)
-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

Name:	us-gaap_RestructuringSettlementAndImpairmentProvisions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration