v2.4.0.8
Employee Benefits - Additional Information (Detail) (USD $)
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2014
Jun. 30, 2013
Jun. 30, 2014
Jun. 30, 2013
Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]          
Pension remeasurement credit (charges)   $ 237,000,000   $ 237,000,000  
Discount rate   5.00%   5.00%  
Expected return on plan assets         7.50%
Amount paid in severance benefits over the period 100,000,000   300,000,000    
Post employment benefits liability 500,000,000   500,000,000    
Pension
          
Defined Benefit Plan Disclosure [Line Items]          
Pension remeasurement credit (charges)   237,000,000   237,000,000  
Pension Remeasurement Credit
          
Defined Benefit Plan Disclosure [Line Items]          
Discount rate basis point increase (decrease)       75  
Discount rate         4.20%
Actual return on assets       7.20%  
Pension Remeasurement Gain Primarily Driven By Increase In Discount Rate Assumption
          
Defined Benefit Plan Disclosure [Line Items]          
Pension remeasurement credit (charges)       300,000,000  
Pension Charges Driven By Difference Between Expected Return on Assets and Annualized Actual Return On Assets And Other
          
Defined Benefit Plan Disclosure [Line Items]          
Pension remeasurement credit (charges)       (100,000,000)  
Other Postretirement Benefit Plans
          
Defined Benefit Plan Disclosure [Line Items]          
Defined benefit plan contributions by employer 400,000,000   900,000,000    
Qualified Pension Plans
          
Defined Benefit Plan Disclosure [Line Items]          
Defined benefit plan contributions by employer $ 600,000,000   $ 800,000,000