v2.4.0.6
Fair Value (Assets and Liabilities Measured At Fair Value On Recurring Basis) (Detail) (USD $)
In Millions, unless otherwise specified
Jul. 28, 2012
Jul. 30, 2011
Level 1
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements $ 4,126 $ 7,213
Level 2
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 37,560 35,662
Liabilities, Fair Value Disclosure 42 24
Level 2 | Derivative Assets
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 263 220
Level 2 | Derivative Liabilities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Liabilities, Fair Value Disclosure 42 24
Level 3
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 1 123
Level 3 | Derivative Assets
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 1 2
Total
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 41,687 42,998
Liabilities, Fair Value Disclosure 42 24
Total | Derivative Assets
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 264 222
Total | Derivative Liabilities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Liabilities, Fair Value Disclosure 42 24
Cash Equivalents | Level 1 | Money market funds
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 2,506 5,852
Cash Equivalents | Level 2 | U.S. Government Agency Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements   1
Cash Equivalents | Total | Money market funds
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 2,506 5,852
Cash Equivalents | Total | U.S. Government Agency Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements   1
Available-For-Sale Investments | Level 1 | Publicly Traded Equity Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 1,620 1,361
Available-For-Sale Investments | Level 2 | U.S. Government Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 24,241 19,139
Available-For-Sale Investments | Level 2 | U.S. Government Agency Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 5,388 8,776
Available-For-Sale Investments | Level 2 | Non-U.S. Government And Agency Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 1,638 3,132
Available-For-Sale Investments | Level 2 | Corporate Debt Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 6,030 4,394
Available-For-Sale Investments | Level 3 | Asset-Backed Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements   121
Available-For-Sale Investments | Total | U.S. Government Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 24,241 19,139
Available-For-Sale Investments | Total | U.S. Government Agency Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 5,388 8,776
Available-For-Sale Investments | Total | Non-U.S. Government And Agency Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 1,638 3,132
Available-For-Sale Investments | Total | Corporate Debt Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements 6,030 4,394
Available-For-Sale Investments | Total | Asset-Backed Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements   121
Available-For-Sale Investments | Total | Publicly Traded Equity Securities
   
Fair Value, Assets And Liabilities Measured On Recurring Basis [Line Items]    
Assets, fair value measurements $ 1,620 $ 1,361