v3.7.0.1
Debt, Total (Details) - USD ($)
$ in Millions
Mar. 31, 2017
Dec. 31, 2016
Debt Instrument    
Total debt $ 3,819 $ 4,109
Unamortized issuance costs (a) (53) (55)
Current Maturities (1) (1)
Debt, Net of Current Maturities and Unamortized Issuance Costs $ 3,765 4,053
5.875% Senior Notes Due 2020 [Member]    
Debt Instrument    
Debt Instrument, Unamortized Premium   $ 4