Financing Receivables and Operating Leases (Summary Of Allowances For Credit Loss And Related Financing Receivables) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 28, 2017	Jan. 23, 2016	Jan. 28, 2017	Jan. 23, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	$ 386	$ 378	$ 375	$ 382
Provisions	1	(9)	9	(5)
Recoveries (write-offs), net	(6)	(1)	(6)	(8)
Foreign exchange and other	(3)	(3)	0	(4)
Allowance for credit loss as of end of period	378	365	378	365
Lease Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	227	255	230	259
Provisions	2	(4)	(2)	(4)
Recoveries (write-offs), net	(2)	0	(2)	(4)
Foreign exchange and other	(2)	(3)	(1)	(3)
Allowance for credit loss as of end of period	225	248	225	248
Loan Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	111	90	97	87
Provisions	0	(10)	12	(6)
Recoveries (write-offs), net	(4)	0	(4)	0
Foreign exchange and other	(1)	0	1	(1)
Allowance for credit loss as of end of period	106	80	106	80
Financed Service Contracts and Other
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of beginning of period	48	33	48	36
Provisions	(1)	5	(1)	5
Recoveries (write-offs), net	0	(1)	0	(4)
Foreign exchange and other	0	0	0	0
Allowance for credit loss as of end of period	$ 47	$ 37	$ 47	$ 37