Financing Receivables - Schedule of Financing Receivables Categorized by Internal Credit Risk Rating (Details) - USD ($) $ in Millions	Jan. 25, 2020	Jul. 27, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	$ 9,596	$ 10,037
1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	5,651	5,984
5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	3,691	3,850
7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	254	203
Lease Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	2,117	2,230
Lease Receivables | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	1,133	1,204
Lease Receivables | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	936	991
Lease Receivables | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	48	35
Loan Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	5,297	5,438
Loan Receivables | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	3,262	3,367
Loan Receivables | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	1,855	1,920
Loan Receivables | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	180	151
Financed Service Contracts
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	2,182	2,369
Financed Service Contracts | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	1,256	1,413
Financed Service Contracts | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	900	939
Financed Service Contracts | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables less unearned income	$ 26	$ 17