Employee Benefit Plans Employee Savings and Retirement Plan (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2018	Sep. 24, 2017	Sep. 25, 2016
Employee Savings and Retirement Plan [Abstract]
Percentage of eligible employee compensation that can be contributed to 401(k) plan subject to annual limits	85.00%
Company's contribution expense to 401(k) plan	$ 78	$ 76	$ 74

Amount of cost for defined contribution plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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