Contingencies - Summary of Insurance Receivable Balances and Activity Related to Cumulative Trauma Product Liability Losses (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Movement in Loss Contingency Receivable, Increase (Decrease) [Roll Forward]
Balance January 1	$ 124.8	$ 130.0	$ 112.1
Additions	98.2	34.0	29.7
Collections and settlements	(2.5)	(39.2)	(11.8)
Balance December 31	$ 220.5	$ 124.8	$ 130.0