Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Supplementary Information [Line Items]
Stock split additional shares issuable			One additional share of common stock for every two shares of common stock
Stock split conversion ratio			1.5
Common stock, par value	$ 0.01		$ 0.01		$ 0.01
Stock-based compensation costs	$ 7.3	$ 5.5	$ 44.5	$ 24.6
Tax benefits from stock-based compensation, operating activities				16.6
Interest income	1.4	1.4	2.9	3.1
Venezuela devaluation-related charges			$ 29.0
Venezuela Operations
Supplementary Information [Line Items]
Official exchange rate of foreign currency (per U.S. dollar) for remeasuring company's consolidated financial statements	6.30		6.30