| 
           Location on the Balance Sheet of Derivative Assets and Liabilities (Detail) (Fair Value, Inputs, Level 2, USD $) 
        In Millions, unless otherwise specified  | 
        
           Sep. 30, 2012 
         | 
        
           Dec. 31, 2011 
         | 
        
           Sep. 30, 2012
 
          Designated as Hedging Instrument
 
          Foreign Exchange Contracts
 
          Other current assets 
         | 
        
           Dec. 31, 2011
 
          Designated as Hedging Instrument
 
          Foreign Exchange Contracts
 
          Other current assets 
         | 
        
           Sep. 30, 2012
 
          Designated as Hedging Instrument
 
          Foreign Exchange Contracts
 
          Other noncurrent assets 
         | 
        
           Dec. 31, 2011
 
          Designated as Hedging Instrument
 
          Foreign Exchange Contracts
 
          Other noncurrent assets 
         | 
        
           Sep. 30, 2012
 
          Designated as Hedging Instrument
 
          Foreign Exchange Contracts
 
          Other non-current liabilities 
         | 
        
           Dec. 31, 2011
 
          Designated as Hedging Instrument
 
          Foreign Exchange Contracts
 
          Other non-current liabilities 
         | 
        
           Sep. 30, 2012
 
          Designated as Hedging Instrument
 
          Interest Rate Contracts
 
          Other current assets 
         | 
        
           Sep. 30, 2011
 
          Designated as Hedging Instrument
 
          Interest Rate Contracts
 
          Other current assets 
         | 
        
           Sep. 30, 2012
 
          Designated as Hedging Instrument
 
          Interest Rate Contracts
 
          Other noncurrent assets 
         | 
        
           Dec. 31, 2011
 
          Designated as Hedging Instrument
 
          Interest Rate Contracts
 
          Other noncurrent assets 
         | 
        
           Sep. 30, 2012
 
          Designated as Hedging Instrument
 
          Interest Rate Contracts
 
          Other non-current liabilities 
         | 
        
           Dec. 31, 2011
 
          Designated as Hedging Instrument
 
          Interest Rate Contracts
 
          Other non-current liabilities 
         | 
        
           Sep. 30, 2012
 
          Not Designated as Hedging Instrument
 
          Foreign Exchange Contracts
 
          Other current assets 
         | 
        
           Dec. 31, 2011
 
          Not Designated as Hedging Instrument
 
          Foreign Exchange Contracts
 
          Other current assets 
         | 
        
           Sep. 30, 2012
 
          Not Designated as Hedging Instrument
 
          Foreign Exchange Contracts
 
          Other current liabilities 
         | 
        
           Dec. 31, 2011
 
          Not Designated as Hedging Instrument
 
          Foreign Exchange Contracts
 
          Other current liabilities 
         | 
        
           Sep. 30, 2012
 
          Not Designated as Hedging Instrument
 
          Interest Rate Contracts
 
          Other noncurrent assets 
         | 
        
           Dec. 31, 2011
 
          Not Designated as Hedging Instrument
 
          Interest Rate Contracts
 
          Other noncurrent assets 
         | 
        
           Sep. 30, 2012
 
          Not Designated as Hedging Instrument
 
          Interest Rate Contracts
 
          Other non-current liabilities 
         | 
        
           Dec. 31, 2011
 
          Not Designated as Hedging Instrument
 
          Interest Rate Contracts
 
          Other non-current liabilities 
         | 
      
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Asset Derivatives | ||||||||||||||||||||||
| Asset Derivatives | $ 716 | $ 649 | $ 75 | $ 164 | $ 18 | $ 0 | $ 10 | $ 0 | $ 446 | $ 401 | $ 60 | $ 2 | $ 107 | $ 82 | ||||||||
| Derivative Liabilities [Abstract] | ||||||||||||||||||||||
| Liability Derivatives | $ 293 | $ 208 | $ 170 | $ 185 | $ 14 | $ 13 | $ (62) | $ 0 | $ 47 | $ 10 |