Fair Value (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Detail) (USD $) In Millions, unless otherwise specified	Apr. 26, 2014	Jul. 27, 2013
Assets at Fair Value, Recurring	$ 48,851	$ 48,912
Cash Equivalents [Member] | Money Market Funds [Member]
Assets at Fair Value, Recurring	4,475	6,045
Available-for-sale Securities | US Government Securities[Member]
Assets at Fair Value, Recurring	31,703	27,823
Available-for-sale Securities | US Government Agencies Securities [Member]
Assets at Fair Value, Recurring	1,061	3,089
Available-for-sale Securities | Non-US Government and Agency Securities [Member]
Assets at Fair Value, Recurring	820	1,095
Available-for-sale Securities | Corporate Debt Securities [Member]
Assets at Fair Value, Recurring	8,115	7,881
Available-for-sale Securities | U.S. agency mortgage-backed Securities
Assets at Fair Value, Recurring	570
Available-for-sale Securities | Publicly Traded Equity Securities
Assets at Fair Value, Recurring	1,959	2,797
Derivative Assets [Member]
Assets at Fair Value, Recurring	148	182
Derivative Liabilities [Member]
Liabilities at Fair Value, Recurring	54	171
Fair Value, Inputs, Level 1 [Member]
Assets at Fair Value, Recurring	6,434	8,842
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Assets at Fair Value, Recurring	4,475	6,045
Fair Value, Inputs, Level 1 [Member] | Publicly Traded Equity Securities
Assets at Fair Value, Recurring	1,959	2,797
Fair Value, Inputs, Level 2 [Member]
Assets at Fair Value, Recurring	42,417	40,070
Fair Value, Inputs, Level 2 [Member] | US Government Securities[Member]
Assets at Fair Value, Recurring	31,703	27,823
Fair Value, Inputs, Level 2 [Member] | US Government Agencies Securities [Member]
Assets at Fair Value, Recurring	1,061	3,089
Fair Value, Inputs, Level 2 [Member] | Non-US Government and Agency Securities [Member]
Assets at Fair Value, Recurring	820	1,095
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member]
Assets at Fair Value, Recurring	8,115	7,881
Fair Value, Inputs, Level 2 [Member] | U.S. agency mortgage-backed Securities
Assets at Fair Value, Recurring	570
Fair Value, Inputs, Level 2 [Member] | Derivative Assets [Member]
Assets at Fair Value, Recurring	148	182
Fair Value, Inputs, Level 2 [Member] | Derivative Liabilities [Member]
Liabilities at Fair Value, Recurring	$ 54	$ 171