Financing Receivables - Schedule of Financing Receivables Categorized by Internal Credit Risk Rating (Details) - USD ($) $ in Millions	Jul. 25, 2020	Jul. 27, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	$ 10,780	$ 10,037
1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	6,445	5,984
5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	4,066	3,850
7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	269	203
Lease receivables
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	2,013	2,230
Lease receivables | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	992	1,204
Lease receivables | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	952	991
Lease receivables | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	69	35
Loan receivables
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	5,937	5,438
Loan receivables | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	3,808	3,367
Loan receivables | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	1,961	1,920
Loan receivables | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	168	151
Financed service contracts
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	2,830	2,369
Financed service contracts | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	1,645	1,413
Financed service contracts | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	1,153	939
Financed service contracts | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	$ 32	$ 17