v2.4.0.8
Fair Value Measurements (Details) (USD $)
In Millions, unless otherwise specified
Jun. 30, 2013
Dec. 31, 2012
Jun. 30, 2012
Dec. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]        
Cash $ 628 $ 577 $ 525 $ 385
Short-term investments 368 527    
Net derivative contracts (13) 83    
Long-term debt converted to floating interest rates by interest rate swaps - net (1) 87    
Quoted prices in active markets for identical assets (Level 1) [Member]
        
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]        
Cash 628 577    
Short-term investments 368 527    
Net derivative contracts 0 0    
Long-term debt converted to floating interest rates by interest rate swaps - net 0 0    
Other Observable inputs Level 2) [Member]
        
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]        
Cash 0 0    
Short-term investments 0 0    
Net derivative contracts (13) 83    
Long-term debt converted to floating interest rates by interest rate swaps - net (1) 87    
Unobservable inputs (Level 3) [Member]
        
Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items]        
Cash 0 0    
Short-term investments 0 0    
Net derivative contracts 0 0    
Long-term debt converted to floating interest rates by interest rate swaps - net $ 0 $ 0