Weighted-Average Assumptions to Determine Postretirement Benefit Obligations (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
U.S. postretirement plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.60%	4.20%
Health care cost trend rate assumed for next year	6.50%	6.50%
Ultimate trend rate	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2020	2018
Foreign Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.77%	4.52%
Health care cost trend rate assumed for next year	5.37%	5.18%
Ultimate trend rate	5.55%	5.53%
Year that the rate reaches the ultimate trend rate	2018	2018