Financing Receivables and Operating Leases (Summary of Allowances for Credit Loss and Related Financing Receivables) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 29, 2017	Jul. 30, 2016	Jul. 25, 2015
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss, beginning of period	$ 375	$ 382	$ 349
Provisions	(35)	17	57
Write-offs, net	(49)	(15)	(7)
Foreign exchange and other	4	(9)	(17)
Allowance for credit loss, end of period	295	375	382
Lease Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss, beginning of period	230	259	233
Provisions	(25)	(13)	45
Write-offs, net	(37)	(10)	(7)
Foreign exchange and other	(6)	(6)	(12)
Allowance for credit loss, end of period	162	230	259
Loan Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss, beginning of period	97	87	98
Provisions	7	13	(8)
Write-offs, net	(11)	0
Recoveries			1
Foreign exchange and other	10	(3)	(4)
Allowance for credit loss, end of period	103	97	87
Financed Service Contracts
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss, beginning of period	48	36	18
Provisions	(17)	17	20
Write-offs, net	(1)	(5)	(1)
Foreign exchange and other	0	0	(1)
Allowance for credit loss, end of period	$ 30	$ 48	$ 36