v2.4.0.8
Stock Based Compensation - Additional Information (Detail) (USD $)
In Billions, except Share data in Millions, unless otherwise specified
6 Months Ended
Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Maximum number of shares available for awards under the Long-Term Incentive Plan 119.6
Restricted Stock Units and Performance Stock Units
 
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Unrecognized compensation expense related to the unvested portion of RSUs and PSUs $ 0.6
Weighted-average period of unrecognized compensation expense related to the unvested portion of RSUs and PSUs (in years) 2 years
Restricted Stock Units
 
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Weighted average grant date fair value per unit $ 47.15