Activity in Number of Shares of Common Stock Issued and Outstanding (Detail)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Equity [Abstract]
At beginning of year	190,641,317		193,723,208		192,836,008
Stock options exercised	303,685	[1]	482,974	[1]	615,674	[1]
Employee stock purchase and thrift plans	16,020		78,389		33,390
Restricted stock awards, net of forfeitures	300,910		224,296		238,136
Treasury shares purchased	(7,855,419)		(3,867,550)		0
At end of year	183,406,513		190,641,317		193,723,208

[1] Shares issued upon exercise of stock options are less than the amount reflected in Note I due to withholdings for statutory income taxes owed upon exercise.