Stockholders' Equity (Detail) - Summary of Transactions Relating to Common Stock	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Common Stock
Common Stock Outstanding Roll Forward [Roll Forward]
Beginning Balance	156,234,415		156,234,415		156,234,415
Issuances under stock plans	0		0		0
Purchases for treasury	0	[1]	0	[1]	0	[1]
Ending Balance	156,234,415		156,234,415		156,234,415
Treasury Stock
Common Stock Outstanding Roll Forward [Roll Forward]
Beginning Balance	64,268,863		62,873,100		62,891,251
Issuances under stock plans	(1,452,419)		(2,037,091)		(2,756,389)
Purchases for treasury	5,897,446	[1]	3,432,854	[1]	2,738,238	[1]
Ending Balance	68,713,890		64,268,863		62,873,100

[1] The Company used a total of $432.0 million, $181.7 million, and $111.3 million in cash for share repurchases in 2014, 2013, and 2012, respectively.