Fair Value (Assets and Liabilities Measured At Fair Value On Recurring Basis) (Detail) (USD $) In Millions, unless otherwise specified	Jul. 27, 2013	Jul. 28, 2012
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	$ 48,912	$ 41,687
Level 1
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	8,842	4,126
Level 2
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	40,070	37,560
Cash Equivalents | Money market funds
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	6,045	2,506
Cash Equivalents | Money market funds | Level 1
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	6,045	2,506
Available-For-Sale Investments | U.S. Government Securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	27,823	24,241
Available-For-Sale Investments | U.S. Government Securities | Level 2
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	27,823	24,241
Available-For-Sale Investments | U.S. Government Agency Securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	3,089	5,388
Available-For-Sale Investments | U.S. Government Agency Securities | Level 2
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	3,089	5,388
Available-For-Sale Investments | Non-U.S. Government And Agency Securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	1,095	1,638
Available-For-Sale Investments | Non-U.S. Government And Agency Securities | Level 2
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	1,095	1,638
Available-For-Sale Investments | Corporate Debt Securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	7,881	6,030
Available-For-Sale Investments | Corporate Debt Securities | Level 2
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	7,881	6,030
Available-For-Sale Investments | Publicly Traded Equity Securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	2,797	1,620
Available-For-Sale Investments | Publicly Traded Equity Securities | Level 1
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	2,797	1,620
Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	182	264
Derivative assets | Level 2
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	182	263
Derivative assets | Level 3
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value measurements	0	1
Derivative liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities, Fair Value Disclosure, Recurring	171	42
Derivative liabilities | Level 2
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities, Fair Value Disclosure, Recurring	$ 171	$ 42