Fair Value (Assets and Liabilities Measured At Fair Value On Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Jan. 24, 2015	Jul. 26, 2014
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	$ 51,557	$ 50,443
Cash equivalents: | Money market funds
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	2,977	4,935
Cash equivalents: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	67	0
Available-for-sale investments: | U.S. government securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	30,354	31,734
Available-for-sale investments: | U.S. government agency securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	2,326	1,063
Available-for-sale investments: | Non-U.S. government and agency securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	1,109	861
Available-for-sale investments: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	11,213	9,159
Available-for-sale investments: | U.S. agency mortgage-backed securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	1,375	579
Available-for-sale investments: | Publicly traded equity securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	1,848	1,952
Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	288	160
Derivative liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities:	162	67
Level 1
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	4,825	6,887
Level 1 | Cash equivalents: | Money market funds
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	2,977	4,935
Level 1 | Cash equivalents: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 1 | Available-for-sale investments: | U.S. government securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 1 | Available-for-sale investments: | U.S. government agency securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 1 | Available-for-sale investments: | Non-U.S. government and agency securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 1 | Available-for-sale investments: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 1 | Available-for-sale investments: | U.S. agency mortgage-backed securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 1 | Available-for-sale investments: | Publicly traded equity securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	1,848	1,952
Level 1 | Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 1 | Derivative liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities:	0	0
Level 2
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	46,732	43,554
Level 2 | Cash equivalents: | Money market funds
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 2 | Cash equivalents: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	67	0
Level 2 | Available-for-sale investments: | U.S. government securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	30,354	31,734
Level 2 | Available-for-sale investments: | U.S. government agency securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	2,326	1,063
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:	1,109	861
Level 2 | Available-for-sale investments: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	11,213	9,159
Level 2 | Available-for-sale investments: | U.S. agency mortgage-backed securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	1,375	579
Level 2 | Available-for-sale investments: | Publicly traded equity securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 2 | Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	288	158
Level 2 | Derivative liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities:	162	67
Level 3
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	2
Level 3 | Cash equivalents: | Money market funds
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 3 | Cash equivalents: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 3 | Available-for-sale investments: | U.S. government securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 3 | Available-for-sale investments: | U.S. government agency securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 3 | Available-for-sale investments: | Non-U.S. government and agency securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 3 | Available-for-sale investments: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 3 | Available-for-sale investments: | U.S. agency mortgage-backed securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 3 | Available-for-sale investments: | Publicly traded equity securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	0
Level 3 | Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets:	0	2
Level 3 | Derivative liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Liabilities:	$ 0	$ 0