Details Of Intangible Assets Included In Other Long-Term Assets (Detail) (USD $)
In Millions, unless otherwise specified
 6 Months Ended
Jun. 30, 2012
Year
Dec. 31, 2011
Acquired Finite-Lived Intangible Assets [Line Items]    
Weighted Average Life, years 11.6  
Cost $ 687 $ 648
Accumulated Amortization 247 213
Net 440 435
Customer contracts/relationships
    
Acquired Finite-Lived Intangible Assets [Line Items]    
Weighted Average Life, years 10.5  
Cost 459 429
Accumulated Amortization 204 182
Net 255 247
Trade names and technology
    
Acquired Finite-Lived Intangible Assets [Line Items]    
Weighted Average Life, years 15.0  
Cost 136 135
Accumulated Amortization 12 6
Net 124 129
Provider contracts
    
Acquired Finite-Lived Intangible Assets [Line Items]    
Weighted Average Life, years 15.1  
Cost 51 44
Accumulated Amortization 17 15
Net 34 29
Noncompetes and Other
    
Acquired Finite-Lived Intangible Assets [Line Items]    
Weighted Average Life, years 7.1  
Cost 41 40
Accumulated Amortization 14 10
Net $ 27 $ 30