Fair Value Measurement - Summary of Changes in Fair Value of all Financial Assets and Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Detail) (Contingent consideration obligations [Member], USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Contingent consideration obligations [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 363.1	$ 181.6
Net transfers in to (out of) Level 3	(335.8)
Purchases and settlements, net	179.0	(115.3)
Net accretion and fair value adjustments	1.4	(15.5)
Foreign currency translation	(1.8)	(0.8)
Ending Balance	$ 205.9	$ 50.0