Special Charges and Certain Litigation Charges (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Oct. 30, 2015	Oct. 24, 2014	Oct. 30, 2015	Oct. 24, 2014
Loss Contingencies [Line Items]
Special gains (charges)	$ 0	$ 100	$ 0	$ 100
Certain litigation charges	26	$ 0	26	$ 0
INFUSE [Member] \| Product liability litigation [Member]
Loss Contingencies [Line Items]
Certain litigation charges	$ 26		$ 26

Amount charged against operating income increasing loss contingency liability, after adjustments to reduce previously estimated charges.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

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