Fair Value (Assets and Liabilities Measured At Fair Value On Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Jul. 26, 2014	Jul. 27, 2013
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	$ 50,443	$ 48,912
Cash equivalents: | Money market funds
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	4,935	6,045
Available-for-sale investments: | U.S. government securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	31,734	27,823
Available-for-sale investments: | U.S. government agency securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	1,063	3,089
Available-for-sale investments: | Non-U.S. government and agency securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	861	1,095
Available-for-sale investments: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	9,159	7,881
Available-for-sale investments: | U.S. agency mortgage-backed securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	579
Available-for-sale investments: | Publicly traded equity securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	1,952	2,797
Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	160	182
Derivative liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities:	67	171
Level 1
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	6,887	8,842
Level 1 | Cash equivalents: | Money market funds
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	4,935	6,045
Level 1 | Available-for-sale investments: | Publicly traded equity securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	1,952	2,797
Level 2
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	43,554	40,070
Level 2 | Available-for-sale investments: | U.S. government securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	31,734	27,823
Level 2 | Available-for-sale investments: | U.S. government agency securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	1,063	3,089
Level 2 | Available-for-sale investments: | Non-U.S. government and agency securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	861	1,095
Level 2 | Available-for-sale investments: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	9,159	7,881
Level 2 | Available-for-sale investments: | U.S. agency mortgage-backed securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	579
Level 2 | Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	158	182
Level 2 | Derivative liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities:	67	171
Level 3
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	2
Level 3 | Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	$ 2