Financing Receivables - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
Jul. 25, 2020	Jul. 27, 2019
Financing Receivables And Guarantees [Line Items]
Average lease term	4 years
Loan receivables term	3 years
Threshold for past due receivables	31 days
Financing receivables 91 days past due and still accruing	$ 67	$ 215
Minimum
Financing Receivables And Guarantees [Line Items]
Financed service contracts term	1 year
Maximum
Financing Receivables And Guarantees [Line Items]
Loan receivables term	3 years
Financed service contracts term	3 years

Amount of financing receivable 90 days or more past due and still accruing.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919258-210447

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5111-111524

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=121647567&loc=SL82922355-210448

Name:	us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant