Fair Value (Assets and Liabilities Measured At Fair Value On Recurring Basis) (Details) - USD ($) $ in Millions	Jul. 30, 2016	Jul. 25, 2015
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value on recurring measurement basis	$ 64,602	$ 59,107
Liabilities, fair value on recurring measurement basis	54	12
Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative Asset	385	218
Derivative liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative Liability	54	12
Cash equivalents: | Money Market Funds [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Money Market Funds	6,049	5,336
Cash equivalents: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	43	14
Available-for-sale investments: | U.S. government securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	26,544	29,939
Available-for-sale investments: | US Government Agencies Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	2,817	3,663
Available-for-sale investments: | Foreign Government Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	1,100	1,128
Available-for-sale investments: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	24,292	15,783
Available-for-sale investments: | Mortgage-backed Securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	1,868	1,461
Available-for-sale investments: | Publicly traded equity securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	1,504	1,565
Level 1
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value on recurring measurement basis	7,553	6,901
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	6,049	5,336
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: | Mortgage-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	1,504	1,565
Level 2
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, fair value on recurring measurement basis	57,048	52,202
Liabilities, fair value on recurring measurement basis	54	12
Level 2 | Derivative assets
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative Asset	384	214
Level 2 | Derivative liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative Liability	54	12
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	43	14
Level 2 | Available-for-sale investments: | U.S. government securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	26,544	29,939
Level 2 | Available-for-sale investments: | US Government Agencies Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	2,817	3,663
Level 2 | Available-for-sale investments: | Foreign Government Debt Securities [Member]
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	1,100	1,128
Level 2 | Available-for-sale investments: | Corporate debt securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	24,292	15,783
Level 2 | Available-for-sale investments: | Mortgage-backed Securities
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]
Investments	1,868	1,461
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	1	4
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	1	4
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: | Mortgage-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