Investments (Summary Of Available-For-Sale Investments) (Details) - USD ($) $ in Millions	Apr. 29, 2017	Jul. 30, 2016
Schedule of Investments [Line Items]
Amortized Cost	$ 59,430	$ 57,479
Gross Unrealized Gains	685	703
Gross Unrealized Losses	(257)	(57)
Fair Value	59,858	58,125
Net unsettled available-for-sale investments, purchases	80	654
Total fixed income securities
Schedule of Investments [Line Items]
Amortized Cost	58,253	56,268
Gross Unrealized Gains	152	370
Gross Unrealized Losses	(253)	(17)
Fair Value	58,152	56,621
Total fixed income securities | U.S. government securities
Schedule of Investments [Line Items]
Amortized Cost	20,951	26,473
Gross Unrealized Gains	4	73
Gross Unrealized Losses	(67)	(2)
Fair Value	20,888	26,544
Total fixed income securities | U.S. government agency securities
Schedule of Investments [Line Items]
Amortized Cost	2,233	2,809
Gross Unrealized Gains	0	8
Gross Unrealized Losses	(6)	0
Fair Value	2,227	2,817
Total fixed income securities | Non-U.S. government and agency securities
Schedule of Investments [Line Items]
Amortized Cost	721	1,096
Gross Unrealized Gains	0	4
Gross Unrealized Losses	(2)	0
Fair Value	719	1,100
Total fixed income securities | Corporate debt securities
Schedule of Investments [Line Items]
Amortized Cost	31,649	24,044
Gross Unrealized Gains	145	263
Gross Unrealized Losses	(160)	(15)
Fair Value	31,634	24,292
Total fixed income securities | U.S. agency mortgage-backed securities
Schedule of Investments [Line Items]
Amortized Cost	2,038	1,846
Gross Unrealized Gains	3	22
Gross Unrealized Losses	(18)	0
Fair Value	2,023	1,868
Total fixed income securities | Commercial paper
Schedule of Investments [Line Items]
Amortized Cost	635
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	635
Total fixed income securities | Certificates of deposit
Schedule of Investments [Line Items]
Amortized Cost	26
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	26
Publicly traded equity securities
Schedule of Investments [Line Items]
Amortized Cost	1,177	1,211
Gross Unrealized Gains	533	333
Gross Unrealized Losses	(4)	(40)
Fair Value	$ 1,706	$ 1,504