Financing Receivables - Schedule of Financing Receivables Categorized by Internal Credit Risk Rating (Details) - USD ($) $ in Millions	Oct. 26, 2019	Jul. 27, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	$ 9,852	$ 10,037
1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	5,861	5,984
5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	3,705	3,850
7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	286	203
Lease Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	2,084	2,230
Lease Receivables | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	1,128	1,204
Lease Receivables | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	904	991
Lease Receivables | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	52	35
Loan Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	5,335	5,438
Loan Receivables | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	3,267	3,367
Loan Receivables | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	1,866	1,920
Loan Receivables | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	202	151
Financed Service Contracts
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	2,433	2,369
Financed Service Contracts | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	1,466	1,413
Financed Service Contracts | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	935	939
Financed Service Contracts | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	$ 32	$ 17