| 
           Amount Recorded in Income Statements for Foreign Currency Forward Contracts Not Designated as Hedges (Detail) (Not Designated as Hedging Instrument, USD $) 
        In Millions, unless otherwise specified  | 
        3 Months Ended | |
|---|---|---|
| 
           Mar. 31, 2013 
         | 
        
           Mar. 31, 2012 
         | 
      |
| 
           Foreign Exchange Contracts | Other Operating Expense 
         | 
        ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Amount of Gain (Loss) Recognized in Income | $ 87 | $ (8) | 
| 
           Foreign Exchange Contracts | Investment Income [Member] 
         | 
        ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Amount of Gain (Loss) Recognized in Income | (5) | 0 | 
| 
           Interest Rate Contract [Member] | Interest Expense [Member] 
         | 
        ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Amount of Gain (Loss) Recognized in Income | $ 0 | $ (3) | 
| X | ||||||||||
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- Details 
          
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| X | ||||||||||
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- Definition 
          Net gain (loss) from the increase (decrease) in fair value of derivative instrument not designated as hedging instrument. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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