v2.4.0.6
Investments (Available-For-Sale Investments With Gross Unrealized Losses) (Detail) (USD $)
In Millions, unless otherwise specified
Jul. 28, 2012
Jul. 30, 2011
Schedule of Investments [Line Items]    
Fair value of investment securities with unrealized losses less than 12 months $ 6,127 $ 3,845
Gross unrealized losses, less than 12 months (12) (16)
Fair value of investment securities with unrealized losses12 months or greater 34 161
Gross unrealized losses, 12 months or greater (3) (6)
Fair value of investment securities with unrealized losses 6,161 4,006
Total gross unrealized losses (15) (22)
Publicly Traded Equity Securities
    
Schedule of Investments [Line Items]    
Fair value of investment securities with unrealized losses less than 12 months 167 112
Gross unrealized losses, less than 12 months (8) (12)
Fair value of investment securities with unrealized losses12 months or greater 20  
Gross unrealized losses, 12 months or greater (3)  
Fair value of investment securities with unrealized losses 187 112
Total gross unrealized losses (11) (12)
Total Fixed Income Securities
    
Schedule of Investments [Line Items]    
Fair value of investment securities with unrealized losses less than 12 months 5,960 3,733
Gross unrealized losses, less than 12 months (4) (4)
Fair value of investment securities with unrealized losses12 months or greater 14 161
Gross unrealized losses, 12 months or greater   (6)
Fair value of investment securities with unrealized losses 5,974 3,894
Total gross unrealized losses (4) (10)
Total Fixed Income Securities | U.S. Government Agency Securities
    
Schedule of Investments [Line Items]    
Fair value of investment securities with unrealized losses less than 12 months 5,357 2,310
Gross unrealized losses, less than 12 months (1) (1)
Fair value of investment securities with unrealized losses 5,357 2,310
Total gross unrealized losses (1) (1)
Total Fixed Income Securities | Non-U.S. Government And Agency Securities
    
Schedule of Investments [Line Items]    
Fair value of investment securities with unrealized losses less than 12 months   875
Gross unrealized losses, less than 12 months   (1)
Fair value of investment securities with unrealized losses   875
Total gross unrealized losses   (1)
Total Fixed Income Securities | Corporate Debt Securities
    
Schedule of Investments [Line Items]    
Fair value of investment securities with unrealized losses less than 12 months 603 548
Gross unrealized losses, less than 12 months (3) (2)
Fair value of investment securities with unrealized losses12 months or greater 14 56
Gross unrealized losses, 12 months or greater   (2)
Fair value of investment securities with unrealized losses 617 604
Total gross unrealized losses (3) (4)
Total Fixed Income Securities | Asset-Backed Securities
    
Schedule of Investments [Line Items]    
Fair value of investment securities with unrealized losses12 months or greater   105
Gross unrealized losses, 12 months or greater   (4)
Fair value of investment securities with unrealized losses   105
Total gross unrealized losses   $ (4)