Financing Receivables and Operating Leases (Schedule of Financing Receivables Categorized by Internal Credit Risk Rating) (Details) - USD ($) $ in Millions	Jan. 26, 2019	Jul. 28, 2018
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 9,669	$ 9,872
1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	5,623	5,946
5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,936	3,786
7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	110	140
Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	9,669	9,872
Lease Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,233	1,294
Lease Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,066	1,199
Lease Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	46	54
Lease Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	2,345	2,547
Loan Receivables | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	3,000	3,184
Loan Receivables | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,875	1,752
Loan Receivables | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	51	63
Loan Receivables | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	4,926	4,999
Financed Service Contracts | 1 to 4
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	1,390	1,468
Financed Service Contracts | 5 to 6
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	995	835
Financed Service Contracts | 7 and Higher
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	13	23
Financed Service Contracts | Total
Financing Receivable, Recorded Investment [Line Items]
Gross receivables less unearned income	$ 2,398	$ 2,326