Stockholders' Equity - Summary of Changes in Stockholders' Equity (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Equity [Abstract]
Stockholders' equity, December 31, 2012			$ 3,833.8
Common stock issued in connection with Actavis Group acquisition			471.7
Common stock issued under employee plans			5.8
Increase in additional paid-in capital for share-based compensation plans			26.0
Net (loss)	(564.8)	(62.2)	(667.6)	(7.4)
Other comprehensive (loss)	7.4	(59.1)	(121.1)	(21.6)
Excess tax benefit from employee stock plans			14.2
Repurchase of common stock			(22.5)
Acquisition of noncontrolling interests			(4.2)
Stockholders' equity, June 30, 2013	$ 3,536.1		$ 3,536.1