Derivatives - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		3 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Fair Value Hedging	Sep. 30, 2012 Fair Value Hedging	Sep. 30, 2013 Fair Value Hedging	Sep. 30, 2012 Fair Value Hedging	Mar. 31, 2012 Senior Notes Eight Point Two Five Percent Due March Fifteen Two Thousand Nineteen	Mar. 13, 2012 Senior Notes Eight Point Two Five Percent Due March Fifteen Two Thousand Nineteen	Mar. 31, 2012 Senior Notes Four Point Nine Five Percent Due April One Two Thousand Fourteen	Apr. 09, 2010 Senior Notes Four Point Nine Five Percent Due April One Two Thousand Fourteen	Sep. 30, 2013 Not Designated as Hedging Instrument Foreign Exchange Contract	Dec. 31, 2012 Not Designated as Hedging Instrument Foreign Exchange Contract	Mar. 31, 2012 Designated as Hedging Instrument Interest Rate Swap	Apr. 09, 2010 Designated as Hedging Instrument Interest Rate Swap
Derivative [Line Items]
Aggregate notional value of foreign exchange forward contracts													$ 524.9	$ 654.2	$ 400.0	$ 600.0
Derivative, inception date									Mar. 13, 2013		Apr. 09, 2010
Debt instrument, face amount									450.0	450.0
Interest rate									8.25%	8.25%	4.95%	4.95%
Maturity date									Mar. 15, 2019		Apr. 01, 2014
Repayment 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	$ 65.6	$ 63.7	$ 193.9	$ 188.0	$ 2.0	$ 1.9	$ 6.5	$ 5.9