Investments (Summary Of Available-For-Sale Investments) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 26, 2014	Jul. 27, 2013
Available-for-sale investments: [Line Items]
Amortized Cost	$ 44,619	$ 41,930
Gross Unrealized Gains	759	825
Gross Unrealized Losses	(30)	(70)
Fair Value	45,348	42,685
Publicly traded equity securities
Available-for-sale investments: [Line Items]
Amortized Cost	1,314	2,063
Gross Unrealized Gains	648	738
Gross Unrealized Losses	(10)	(4)
Fair Value	1,952	2,797
Total fixed income securities
Available-for-sale investments: [Line Items]
Amortized Cost	43,305	39,867
Gross Unrealized Gains	111	87
Gross Unrealized Losses	(20)	(66)
Fair Value	43,396	39,888
Total fixed income securities | U.S. government securities
Available-for-sale investments: [Line Items]
Amortized Cost	31,717	27,814
Gross Unrealized Gains	29	22
Gross Unrealized Losses	(12)	(13)
Fair Value	31,734	27,823
Total fixed income securities | U.S. government agency securities
Available-for-sale investments: [Line Items]
Amortized Cost	1,062	3,083
Gross Unrealized Gains	1	7
Gross Unrealized Losses	0	(1)
Fair Value	1,063	3,089
Total fixed income securities | Non-U.S. government and agency securities
Available-for-sale investments: [Line Items]
Amortized Cost	860	1,094
Gross Unrealized Gains	2	3
Gross Unrealized Losses	(1)	(2)
Fair Value	861	1,095
Total fixed income securities | Corporate debt securities
Available-for-sale investments: [Line Items]
Amortized Cost	9,092	7,876
Gross Unrealized Gains	74	55
Gross Unrealized Losses	(7)	(50)
Fair Value	9,159	7,881
Total fixed income securities | U.S. agency mortgage-backed securities
Available-for-sale investments: [Line Items]
Amortized Cost	574
Gross Unrealized Gains	5
Gross Unrealized Losses	0
Fair Value	$ 579