Investments (Realized Net Gains (Losses) Related To Available-For-Sale Investments) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 26, 2014	Jul. 27, 2013	Jul. 28, 2012
Schedule of Available-for-sale Securities [Line Items]
Total	$ 300	$ 48	$ 101
Net gains on investments in publicly traded equity securities
Schedule of Available-for-sale Securities [Line Items]
Total	253	17	43
Net gains on investments in fixed income securities
Schedule of Available-for-sale Securities [Line Items]
Total	$ 47	$ 31	$ 58