Financing Receivables and Operating Leases (Summary of Allowances for Credit Loss and Related Financing Receivables) (Details) - USD ($) $ in Millions	12 Months Ended
	Jul. 28, 2018	Jul. 29, 2017	Jul. 30, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss, beginning of period	$ 295	$ 375	$ 382
Provisions (benefits)	(89)	(35)	17
Recoveries (write-offs), net	(6)	(49)	(15)
Foreign exchange and other	5	4	(9)
Allowance for credit loss, end of period	205	295	375
Lease Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss, beginning of period	162	230	259
Provisions (benefits)	(26)	(25)	(13)
Recoveries (write-offs), net	(1)	(37)	(10)
Foreign exchange and other	0	(6)	(6)
Allowance for credit loss, end of period	135	162	230
Loan Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss, beginning of period	103	97	87
Provisions (benefits)	(43)	7	13
Recoveries (write-offs), net	(5)	(11)	0
Foreign exchange and other	5	10	(3)
Allowance for credit loss, end of period	60	103	97
Financed Service Contracts
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss, beginning of period	30	48	36
Provisions (benefits)	(20)	(17)	17
Recoveries (write-offs), net	0	(1)	(5)
Foreign exchange and other	0	0	0
Allowance for credit loss, end of period	$ 10	$ 30	$ 48