Financial Instruments - Net Investment Hedge Derivative Instruments on OCI (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)	$ 1.3	$ (0.7)	$ 1.3	$ 0.7
Amount of Gain (Loss) Reclassified from Accumulated OCI (Effective Portion)	0	0	0	0
Euro-denominated [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)	0.2	(0.2)	0.3	(0.1)
Amount of Gain (Loss) Reclassified from Accumulated OCI (Effective Portion)	0	0	0	0
Canadian dollar-denominated [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives (Effective Portion)	1.1	(0.5)	1.0	0.8
Amount of Gain (Loss) Reclassified from Accumulated OCI (Effective Portion)	$ 0	$ 0	$ 0	$ 0