Fair Value (Assets and Liabilities Measured At Fair Value On Recurring Basis) (Details) - USD ($) $ in Millions	Jul. 25, 2015	Jul. 26, 2014
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value on recurring measurement basis	$ 59,107	$ 50,443
Liabilities, fair value on recurring measurement basis	12	67
Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative Asset	218	160
Derivative liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative Liability	12	67
Cash equivalents: | Money Market Funds [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Money Market Funds	5,336	4,935
Cash equivalents: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	14	0
Available-for-sale investments: | U.S. government securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	29,939	31,734
Available-for-sale investments: | US Government Agencies Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	3,663	1,063
Available-for-sale investments: | Foreign Government Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	1,128	861
Available-for-sale investments: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	15,783	9,159
Available-for-sale investments: | Asset-backed Securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	1,461	579
Available-for-sale investments: | Publicly traded equity securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	1,565	1,952
Level 1
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value on recurring measurement basis	6,901	6,887
Liabilities, fair value on recurring measurement basis	0	0
Level 1 | Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative Asset	0	0
Level 1 | Derivative liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative Liability	0	0
Level 1 | Cash equivalents: | Money Market Funds [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Money Market Funds	5,336	4,935
Level 1 | Cash equivalents: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	0	0
Level 1 | Available-for-sale investments: | U.S. government securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	0	0
Level 1 | Available-for-sale investments: | US Government Agencies Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	0	0
Level 1 | Available-for-sale investments: | Foreign Government Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	0	0
Level 1 | Available-for-sale investments: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	0	0
Level 1 | Available-for-sale investments: | Asset-backed Securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	0	0
Level 1 | Available-for-sale investments: | Publicly traded equity securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	1,565	1,952
Level 2
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value on recurring measurement basis	52,202	43,554
Liabilities, fair value on recurring measurement basis	12	67
Level 2 | Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative Asset	214	158
Level 2 | Derivative liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative Liability	12	67
Level 2 | Cash equivalents: | Money Market Funds [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Money Market Funds	0	0
Level 2 | Cash equivalents: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	14	0
Level 2 | Available-for-sale investments: | U.S. government securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	29,939	31,734
Level 2 | Available-for-sale investments: | US Government Agencies Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	3,663	1,063
Level 2 | Available-for-sale investments: | Foreign Government Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	1,128	861
Level 2 | Available-for-sale investments: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	15,783	9,159
Level 2 | Available-for-sale investments: | Asset-backed Securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	1,461	579
Level 2 | Available-for-sale investments: | Publicly traded equity securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	0	0
Level 3
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value on recurring measurement basis	4	2
Liabilities, fair value on recurring measurement basis	0	0
Level 3 | Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative Asset	4	2
Level 3 | Derivative liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative Liability	0	0
Level 3 | Cash equivalents: | Money Market Funds [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Money Market Funds	0	0
Level 3 | Cash equivalents: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	0	0
Level 3 | Available-for-sale investments: | U.S. government securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	0	0
Level 3 | Available-for-sale investments: | US Government Agencies Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	0	0
Level 3 | Available-for-sale investments: | Foreign Government Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	0	0
Level 3 | Available-for-sale investments: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	0	0
Level 3 | Available-for-sale investments: | Asset-backed Securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	0	0
Level 3 | Available-for-sale investments: | Publicly traded equity securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	$ 0	$ 0