Derivatives - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended								12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Fair Value Hedging	Dec. 31, 2011 Fair Value Hedging	Dec. 31, 2010 Fair Value Hedging	Dec. 31, 2012 Senior Notes Eight Point Twenty Five Percent Due March Fifteen Two Thousand Nineteen	Mar. 13, 2012 Senior Notes Eight Point Twenty Five Percent Due March Fifteen Two Thousand Nineteen	Dec. 31, 2012 Senior Notes Four Point Nine Five Percent Due April One Two Thousand Fourteen
Derivative [Line Items]
Aggregate notional value of foreign exchange forward contracts	$ 654.2	$ 78.3
Derivative, inception date							Mar. 13, 2012		Apr. 09, 2010
Notional amount of interest rate fair value hedge derivatives							400.0		600.0
Debt instrument, face amount							450.0	450.0
Interest rate							8.25%	8.25%	4.95%
Maturity date							Mar. 15, 2019		Apr. 01, 2014
Repurchase of debt									341.8
Terminated portion of interest rate swap agreement, notional amount									342.0
Proceeds from termination of interest rate swaps	11.0
Reduction to interest expense	$ 251.8	$ 243.3	$ 222.6	$ (8.0)	$ (9.9)	$ (6.8)