Income Taxes (Tables)
 3 Months Ended
Mar. 31, 2015
Income Tax Disclosure [Abstract]  
Schedule of Effective Income Tax Rate Calculation
The following table presents the calculation of the Company's effective income tax rate (dollars in millions, except effective income tax rate):
 
For the Three Months Ended March 31,
 
2015
 
2014
Income before income tax expense
$
908

 
$
1,022

Income tax expense
$
322

 
$
391

Effective income tax rate
35.5
%
 
38.3
%