Stockholders' Equity - Total Share-based Incentive Compensation Expense (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	[1]	Jun. 30, 2015	[1]	Jun. 30, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Total share-based incentive compensation expense	$ 14.9		$ 33.2		$ 26.4

[1] The amounts included above do not include the expense related to our U.S. profit sharing contributions made in the form of our common stock or the expense or income related to SARs and other cash-based awards. See Stock Appreciation Rights above for further details of SARs. At June 30, 2015, our other cash-based awards were not material to our condensed consolidated financial positions or results of operations.