Financing Receivables and Operating Leases - Schedule of Financing Receivables Categorized by Internal Credit Risk Rating (Details) - USD ($) $ in Millions	Jul. 27, 2019	Jul. 28, 2018
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	$ 10,037	$ 9,872
1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	5,984	5,946
5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	3,850	3,786
7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	203	140
Lease receivables
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	2,230	2,547
Lease receivables | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	1,204	1,294
Lease receivables | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	991	1,199
Lease receivables | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	35	54
Loan receivables
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	5,438	4,999
Loan receivables | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	3,367	3,184
Loan receivables | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	1,920	1,752
Loan receivables | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	151	63
Financed service contracts
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	2,369	2,326
Financed service contracts | 1 to 4
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	1,413	1,468
Financed service contracts | 5 to 6
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	939	835
Financed service contracts | 7 and Higher
Financing Receivable, Credit Quality Indicator [Line Items]
Gross receivables	$ 17	$ 23