Fair Value (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Detail) (USD $) In Millions, unless otherwise specified	Jan. 25, 2014	Jul. 27, 2013
Assets at Fair Value, Recurring	$ 45,227	$ 48,912
Cash Equivalents [Member] | Money Market Funds [Member]
Assets at Fair Value, Recurring	3,337	6,045
Available-for-sale Securities | US Government Securities[Member]
Assets at Fair Value, Recurring	29,191	27,823
Available-for-sale Securities | US Government Agencies Securities [Member]
Assets at Fair Value, Recurring	1,309	3,089
Available-for-sale Securities | Non-US Government and Agency Securities [Member]
Assets at Fair Value, Recurring	688	1,095
Available-for-sale Securities | Corporate Debt Securities [Member]
Assets at Fair Value, Recurring	8,090	7,881
Available-for-sale Securities | U.S. agency mortgage-backed Securities
Assets at Fair Value, Recurring	453
Available-for-sale Securities | Equity Securities [Member]
Assets at Fair Value, Recurring	1,995	2,797
Derivative Assets [Member]
Assets at Fair Value, Recurring	164	182
Derivative Liabilities [Member]
Liabilities at Fair Value, Recurring	53	171
Fair Value, Inputs, Level 1 [Member]
Assets at Fair Value, Recurring	5,332	8,842
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Assets at Fair Value, Recurring	3,337	6,045
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Assets at Fair Value, Recurring	1,995	2,797
Fair Value, Inputs, Level 2 [Member]
Assets at Fair Value, Recurring	39,895	40,070
Fair Value, Inputs, Level 2 [Member] | US Government Securities[Member]
Assets at Fair Value, Recurring	29,191	27,823
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Securities [Member]
Assets at Fair Value, Recurring	1,309	3,089
Fair Value, Inputs, Level 2 [Member] | Non-US Government and Agency Securities [Member]
Assets at Fair Value, Recurring	688	1,095
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Assets at Fair Value, Recurring	8,090	7,881
Fair Value, Inputs, Level 2 [Member] | U.S. agency mortgage-backed Securities
Assets at Fair Value, Recurring	453
Fair Value, Inputs, Level 2 [Member] | Derivative Assets [Member]
Assets at Fair Value, Recurring	164	182
Fair Value, Inputs, Level 2 [Member] | Derivative Liabilities [Member]
Liabilities at Fair Value, Recurring	$ 53	$ 171