Employee Benefits and Deferred Compensation - Amount Contributed under 401(k) Plans (Detail) - USD ($) $ in Millions	12 Months Ended
Apr. 26, 2019	Apr. 27, 2018	Apr. 28, 2017
Compensation And Retirement Disclosure [Abstract]
401(k) matching contributions	$ 29	$ 28	$ 30

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