v3.4.0.3
Employee Benefits - Additional Information (Detail)
$ in Millions
 3 Months Ended
Mar. 31, 2016
USD ($)
plan
Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]    
Number of defined benefit pension plans | plan 7  
Basis point decrease in discount rate assumption 0.43%  
Amount paid in severance benefits over the period $ 300  
Post employment benefits liability $ 500  
Weighted Average    
Defined Benefit Plan Disclosure [Line Items]    
Discount rate assumption 4.21% 4.60%
Pension    
Defined Benefit Plan Disclosure [Line Items]    
Pension remeasurement credit (charge) $ (165)  
Other Postretirement Benefit Plan    
Defined Benefit Plan Disclosure [Line Items]    
Defined benefit plan contributions by employer 300  
Qualified pension plans    
Defined Benefit Plan Disclosure [Line Items]    
Defined benefit plan contributions by employer 100  
Change method used to estimate interest component of net periodic benefit cost for pension and other Postretirement benefits    
Defined Benefit Plan Disclosure [Line Items]    
Interest cost (100)  
Increase to Net income $ 100