Stockholders' Equity - Summary of Activities Related to Dividends on Common Stock (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Jul. 28, 2017	Jul. 29, 2016
Dividends, Common Stock [Abstract]
Dividends per share declared	$ 0.20	$ 0.19
Dividend payments	$ 54	$ 53
Additional Paid-in Capital
Dividends, Common Stock [Abstract]
Dividend payments		50
Retained Earnings
Dividends, Common Stock [Abstract]
Dividend payments	$ 54	$ 3

Cash outflow in the form of capital distributions and dividends to common shareholders, preferred shareholders and noncontrolling interests.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

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