Fair Value (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Detail) (USD $) In Millions, unless otherwise specified	Oct. 26, 2013	Jul. 27, 2013
Assets at Fair Value, Recurring	$ 46,316	$ 48,912
Cash Equivalents [Member] | Money Market Funds [Member]
Assets at Fair Value, Recurring	3,145	6,045
Available-for-sale Securities [Member] | US Government Securities[Member]
Assets at Fair Value, Recurring	28,638	27,823
Available-for-sale Securities [Member] | US Government Agencies Securities [Member]
Assets at Fair Value, Recurring	2,399	3,089
Available-for-sale Securities [Member] | Non-US Government and Agency Securities [Member]
Assets at Fair Value, Recurring	909	1,095
Available-for-sale Securities [Member] | Corporate Debt Securities [Member]
Assets at Fair Value, Recurring	8,026	7,881
Available-for-sale Securities [Member] | U.S. agency mortgage-backed Securities
Assets at Fair Value, Recurring	461
Available-for-sale Securities [Member] | Equity Securities [Member]
Assets at Fair Value, Recurring	2,514	2,797
Derivative Assets [Member]
Assets at Fair Value, Recurring	224	182
Derivative Liabilities [Member]
Liabilities at Fair Value, Recurring	145	171
Fair Value, Inputs, Level 1 [Member]
Assets at Fair Value, Recurring	5,659	8,842
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Assets at Fair Value, Recurring	3,145	6,045
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Assets at Fair Value, Recurring	2,514	2,797
Fair Value, Inputs, Level 2 [Member]
Assets at Fair Value, Recurring	40,657	40,070
Fair Value, Inputs, Level 2 [Member] | US Government Securities[Member]
Assets at Fair Value, Recurring	28,638	27,823
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Securities [Member]
Assets at Fair Value, Recurring	2,399	3,089
Fair Value, Inputs, Level 2 [Member] | Non-US Government and Agency Securities [Member]
Assets at Fair Value, Recurring	909	1,095
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Assets at Fair Value, Recurring	8,026	7,881
Fair Value, Inputs, Level 2 [Member] | U.S. agency mortgage-backed Securities
Assets at Fair Value, Recurring	461
Fair Value, Inputs, Level 2 [Member] | Derivative Assets [Member]
Assets at Fair Value, Recurring	224	182
Fair Value, Inputs, Level 2 [Member] | Derivative Liabilities [Member]
Liabilities at Fair Value, Recurring	$ 145	$ 171