Derivatives and Currency Exchange Risk Management - Gains (Losses) Recognized in AOCI, Cash Flow Hedges (Details) - Currency exchange rate contracts - Cash flow hedging - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Oct. 25, 2019	Oct. 26, 2018	Oct. 25, 2019	Oct. 26, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Recognized in AOCI, Cash flow hedges	$ 76		$ 103
Recognized in AOCI, Cash flow hedges		$ 174		$ 444

Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 20
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109974929&loc=SL110061190-113977

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580

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