Financial Instruments and Hedging Activities (Fair Values of Derivative Instruments Included on Consolidated Balance Sheet) (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	$ 162.3	$ 181.3
Liability Derivatives Fair Value	(40.2)	(5.6)
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	2.8	36.9
Liability Derivatives Fair Value	(31.0)	(3.7)
Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Asset Derivatives Fair Value	159.5	144.4
Liability Derivatives Fair Value	$ (9.2)	$ (1.9)