Financial Instruments , Activity Related to the Company's Investment Portfolio, Equity and Other Investments (Details) - USD ($) $ in Millions	12 Months Ended
Apr. 26, 2019	Apr. 27, 2018	Apr. 28, 2017
Investment [Line Items]
Proceeds from sales	$ 4,683	$ 4,227	$ 5,356
Recognized impairment losses	0	(227)	0
Equity Investments
Investment [Line Items]
Proceeds from sales	964	918	1,710
Gross realized gains	134	18	75
Gross realized losses	(30)	(4)	(42)
Recognized impairment losses	$ (45)	$ (231)	$ (30)

The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 8A
-URI http://asc.fasb.org/extlink&oid=118954083&loc=SL6284422-111562

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