Financing Receivables and Operating Leases (Summary Of Allowances For Credit Loss And Related Financing Receivables) (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 28, 2017	Oct. 29, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	$ 295	$ 375
Provisions	(6)	8
Foreign exchange and other	0	3
Allowance for credit loss as of end of period	289	386
Lease Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	162	230
Provisions	(2)	(4)
Foreign exchange and other	0	1
Allowance for credit loss as of end of period	160	227
Loan Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	103	97
Provisions	2	12
Foreign exchange and other	1	2
Allowance for credit loss as of end of period	106	111
Financed Service Contracts
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	30	48
Provisions	(6)	0
Foreign exchange and other	(1)	0
Allowance for credit loss as of end of period	$ 23	$ 48