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           Summary of Intangible Assets (Detail) (USD $) 
        In Millions, unless otherwise specified  | 
        
           Sep. 30, 2012 
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           Dec. 31, 2011 
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|---|---|---|
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross Carrying Amount | $ 2,587 | $ 2,389 | 
| Accumulated Amortization | (1,973) | (1,804) | 
| Net Carrying Value | 614 | 585 | 
| 
           Trademarks, licenses, patents, and other 
         | 
        ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross Carrying Amount | 186 | 146 | 
| Accumulated Amortization | (89) | (54) | 
| Net Carrying Value | 97 | 92 | 
| 
           Customer lists 
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        ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross Carrying Amount | 130 | 120 | 
| Accumulated Amortization | (75) | (66) | 
| Net Carrying Value | 55 | 54 | 
| 
           Franchise rights 
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        ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross Carrying Amount | 111 | 109 | 
| Accumulated Amortization | (62) | (58) | 
| Net Carrying Value | 49 | 51 | 
| 
           Capitalized software 
         | 
        ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross Carrying Amount | 2,160 | 2,014 | 
| Accumulated Amortization | (1,747) | (1,626) | 
| Net Carrying Value | $ 413 | $ 388 | 
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- Definition 
          Intangible Assets, Gross No definition available. 
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- Definition 
          The accumulated amount of amortization of a major finite-lived intangible asset class. A major class is composed of intangible assets that can be grouped together because they are similar, either by their nature or by their use in the operations of a company. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
          
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- Definition 
          Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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