Weighted Average Asset Allocation for Pension Plans and Target Allocation (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	100.00%
Actual Allocation	100.00%	100.00%
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	58.00%
Equity Securities | United States
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	49.00%
Actual Allocation	48.00%	48.00%
Equity Securities | International
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	9.00%
Actual Allocation	10.00%	9.00%
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	42.00%
Actual Allocation	41.00%	42.00%
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	0.00%
Actual Allocation	1.00%	1.00%