Financing Receivables - Schedule of Financing Receivables Categorized by Internal Credit Risk Rating (Details) - USD ($) $ in Millions	Apr. 25, 2020	Jul. 27, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	$ 9,474	$ 10,037
1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	5,440	5,984
5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	3,794	3,850
7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	240	203
Lease Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	2,048	2,230
Lease Receivables | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	1,033	1,204
Lease Receivables | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	969	991
Lease Receivables | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	46	35
Loan Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	5,259	5,438
Loan Receivables | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	3,180	3,367
Loan Receivables | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	1,914	1,920
Loan Receivables | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	165	151
Financed Service Contracts
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	2,167	2,369
Financed Service Contracts | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	1,227	1,413
Financed Service Contracts | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	911	939
Financed Service Contracts | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	$ 29	$ 17