Pension Plans Asset Allocations (Detail)	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	100.00%	100.00%
U.S. Equity
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	9.40%	10.60%
Global ex U.S. Equity
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	9.60%	8.00%
Global ex Emerging Markets Equity
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	4.70%	3.80%
Emerging Markets Equity
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	3.90%	3.70%
Absolute Return Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	16.60%	13.90%
Equity Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	13.60%	11.40%
Private Equity
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	4.50%	4.70%
Private Real Assets
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	2.90%	2.20%
Public Real Assets
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	2.00%	2.30%
Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	29.50%	37.30%
Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	3.30%	2.10%