Financing Receivables and Operating Leases (Summary Of Allowances For Credit Loss And Related Financing Receivables) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jan. 24, 2015		Jan. 25, 2014		Jan. 24, 2015		Jan. 25, 2014		Jul. 26, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of	$ 368		$ 350		$ 349		$ 344
Provisions	14		29		42		32
Recoveries (write off), net			1				1
Recoveries (write-offs), net	(1)				(4)
Foreign exchange and other	(6)		(6)		(12)		(3)
Allowance for credit loss as of	375		374		375		374
Total financing receivables before allowance for credit loss	8,134	[1]	8,018	[1]	8,134	[1]	8,018	[1]	8,420
Lease Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of	248		237		233		238
Provisions	7		18		29		15
Recoveries (write off), net			1				1
Recoveries (write-offs), net	(1)				(5)
Foreign exchange and other	(4)		(2)		(7)		0
Allowance for credit loss as of	250		254		250		254
Total financing receivables before allowance for credit loss	3,391	[1]	3,551	[1]	3,391	[1]	3,551	[1]
Loan Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of	84		93		98		86
Provisions	3		9		(10)		15
Recoveries (write off), net			0		1		0
Recoveries (write-offs), net	0
Foreign exchange and other	(2)		(4)		(4)		(3)
Allowance for credit loss as of	85		98		85		98
Total financing receivables before allowance for credit loss	1,674	[1]	1,660	[1]	1,674	[1]	1,660	[1]
Financed Service Contracts and Other
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for credit loss as of	36		20		18		20
Provisions	4		2		23		2
Recoveries (write off), net			0				0
Recoveries (write-offs), net	0				0
Foreign exchange and other	0		0		(1)		0
Allowance for credit loss as of	40		22		40		22
Total financing receivables before allowance for credit loss	$ 3,069	[1]	$ 2,807	[1]	$ 3,069	[1]	$ 2,807	[1]

[1] Total financing receivables before allowance for credit loss.