Computation of Weighted Average Shares Outstanding (Detail) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Earnings Per Share Disclosure [Line Items]
Basic	125.2		111.1
Dilutive share-based awards	1.0	[1]
Convertible debt	2.6
Diluted	128.8		111.1

[1] The three months ended March 31, 2013 excludes 0.8 million potentially dilutive share-based awards as their effect would be anti-dilutive.