v3.7.0.1
Income Taxes (Schedule of Income Tax Provision and Effective Tax Rate) (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Income Tax Disclosure [Abstract]    
Income tax expense $ 24 $ 51
Effective tax rate (percent) 12.40% 35.80%