Weighted Average Assumptions used in Determining Benefit Obligations (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	4.98%	4.27%
Rate of compensation increase	3.00%	3.00%
Initial healthcare trend rate
Ultimate healthcare trend rate
Other Benefit
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	4.70%	3.83%
Rate of compensation increase
Initial healthcare trend rate	7.00%	8.15%
Ultimate healthcare trend rate	5.00%	5.00%	5.00%