Assumptions Used To Determine Compensation Expense for Management Stock Purchase Program (Detail) (Management Stock Purchase Plan, USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Management Stock Purchase Plan
Share Based Compensation [Line Items]
Dividend yield	0.80%	0.90%	0.80%
Risk-free interest rate	0.10%	0.16%	0.12%
Expected life in years	7 months 6 days	7 months 6 days	7 months 6 days
Expected volatility	15.00%	20.00%	16.00%
Fair value	$ 37.20	$ 38.33	$ 38.25