Financial Instruments - Available-For-Sale Securities in Continuous Unrealized Loss Position (Details) - USD ($) $ in Millions	Jul. 31, 2020	Apr. 24, 2020
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair Value	$ 168	$ 1,453
Less than 12 months, Unrealized Losses	(5)	(6)
More than 12 months, Fair Value	1,274	4,019
More than 12 months, Unrealized Losses	(67)	(135)
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair Value	128	1,368
Less than 12 months, Unrealized Losses	(1)	(2)
More than 12 months, Fair Value	821	2,893
More than 12 months, Unrealized Losses	(38)	(88)
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair Value	26	35
Less than 12 months, Unrealized Losses	(3)	(1)
More than 12 months, Fair Value	113	663
More than 12 months, Unrealized Losses	(19)	(27)
Other asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair Value	3	17
Less than 12 months, Unrealized Losses	0	0
More than 12 months, Fair Value	340	463
More than 12 months, Unrealized Losses	(10)	(20)
Auction rate securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Fair Value	11	33
Less than 12 months, Unrealized Losses	(1)	(3)
More than 12 months, Fair Value	0	0
More than 12 months, Unrealized Losses	$ 0	$ 0

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121582814&loc=SL82922890-210455

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27337-111563

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456

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- Definition

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121582814&loc=SL82922890-210455

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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