Employee Benefit Plans (Summary Of Share-Based Compensation Expense) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 26, 2013	Jan. 28, 2012	Jan. 26, 2013	Jan. 28, 2012
Option Indexed to Issuer's Equity [Line Items]
Allocated Share-based Compensation Expense	$ 302	$ 354	$ 608	$ 695
Cost Of Sales Product [Member]
Option Indexed to Issuer's Equity [Line Items]
Allocated Share-based Compensation Expense	11	14	21	27
Cost Of Sales-Service [Member]
Option Indexed to Issuer's Equity [Line Items]
Allocated Share-based Compensation Expense	36	40	71	77
Share-Based Compensation Expense In Cost Of Sales [Member]
Option Indexed to Issuer's Equity [Line Items]
Allocated Share-based Compensation Expense	47	54	92	104
Research And Development [Member]
Option Indexed to Issuer's Equity [Line Items]
Allocated Share-based Compensation Expense	72	99	156	200
Sales And Marketing [Member]
Option Indexed to Issuer's Equity [Line Items]
Allocated Share-based Compensation Expense	135	149	265	291
General And Administrative [Member]
Option Indexed to Issuer's Equity [Line Items]
Allocated Share-based Compensation Expense	48	54	98	102
Restructuring And Other Charges [Member]
Option Indexed to Issuer's Equity [Line Items]
Allocated Share-based Compensation Expense	0	(2)	(3)	(2)
Share-Based Compensation Expense In Operating Expenses [Member]
Option Indexed to Issuer's Equity [Line Items]
Allocated Share-based Compensation Expense	$ 255	$ 300	$ 516	$ 591