v2.4.0.6
Unrealized Gains and Losses Related To Investments in Marketable Securities Designated as Available-for-Sale (Detail) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2011
Dec. 31, 2010
Schedule of Available-for-sale Securities [Line Items]    
Adjusted Cost $ 34,174 $ 21,166
Gross Unrealized Gains 583 304
Gross Unrealized Losses (114) (125)
Fair Value 34,643 21,345
Time deposits
   
Schedule of Available-for-sale Securities [Line Items]    
Adjusted Cost 495 307
Gross Unrealized Gains 0 0
Gross Unrealized Losses 0 0
Fair Value 495 307
U.S. government agencies
   
Schedule of Available-for-sale Securities [Line Items]    
Adjusted Cost 6,211 1,864
Gross Unrealized Gains 15 1
Gross Unrealized Losses 0 (8)
Fair Value 6,226 1,857
U.S. government notes
   
Schedule of Available-for-sale Securities [Line Items]    
Adjusted Cost 11,475 3,950
Gross Unrealized Gains 104 30
Gross Unrealized Losses 0 (50)
Fair Value 11,579 3,930
Foreign government bonds
   
Schedule of Available-for-sale Securities [Line Items]    
Adjusted Cost 1,608 1,154
Gross Unrealized Gains 32 23
Gross Unrealized Losses (11) (5)
Fair Value 1,629 1,172
Municipal securities
   
Schedule of Available-for-sale Securities [Line Items]    
Adjusted Cost 1,775 2,492
Gross Unrealized Gains 19 16
Gross Unrealized Losses 0 (5)
Fair Value 1,794 2,503
Corporate debt securities
   
Schedule of Available-for-sale Securities [Line Items]    
Adjusted Cost 6,023 5,600
Gross Unrealized Gains 187 167
Gross Unrealized Losses (98) (25)
Fair Value 6,112 5,742
Agency residential mortgage-backed securities
   
Schedule of Available-for-sale Securities [Line Items]    
Adjusted Cost 6,359 5,649
Gross Unrealized Gains 147 56
Gross Unrealized Losses (5) (32)
Fair Value 6,501 5,673
Marketable equity securities
   
Schedule of Available-for-sale Securities [Line Items]    
Adjusted Cost 228 150
Gross Unrealized Gains 79 11
Gross Unrealized Losses 0 0
Fair Value $ 307 $ 161