v3.3.1.900
Fair Value Measurements (Details) - USD ($)
$ in Millions
Dec. 31, 2015
Dec. 31, 2014
Summary of financial instruments recognized at fair value and fair value measurement used    
Cash $ 268 $ 781
Short-term investments 177 245
Net derivative contracts 86 70
Long-term debt converted to floating interest rates by interest rate swaps - net (94) (74)
Quoted prices in active markets for identical assets (Level 1) [Member]    
Summary of financial instruments recognized at fair value and fair value measurement used    
Cash 268 781
Short-term investments 177 245
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]    
Summary of financial instruments recognized at fair value and fair value measurement used    
Cash 0 0
Short-term investments 0 0
Net derivative contracts 86 70
Long-term debt converted to floating interest rates by interest rate swaps - net (94) (74)
Unobservable inputs (Level 3) [Member]    
Summary of financial instruments recognized at fair value and fair value measurement used    
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