Business Combination - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended				0 Months Ended
	Jul. 27, 2013	Jul. 28, 2012	Jul. 30, 2011	Jul. 27, 2013 Excluding NDS [Member] acquisition	Jul. 27, 2013 Sourcefire Inc [Member]
Business Acquisition [Line Items]
Repayments of debt	$ 993
Number of business combinations (in numbers)				12
Acquired Cash and Cash Equivalents	156
Business Acquisition, Transaction Costs	40	15	10
Purchase Consideration	$ 1,977	$ 398	$ 288		$ 2,700