Reconciliation of income tax computed at US Federal tax rates (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax [Abstract]
Statutory Income Tax	35.00%	35.00%	35.00%
Prior Year Taxes	(0.10%)	(0.90%)	(11.00%)
Foreign Items	(1.90%)	(2.00%)	(0.30%)
Tax Credits	(3.40%)	(2.70%)	(5.90%)
Other Items, Net	(0.80%)	(1.00%)	(3.10%)
Effective Tax	28.80%	28.40%	14.70%