Fair Value Disclosures - Summary of Non-Pension Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, Assets	$ 17.6	$ 33.3
Derivatives, Liabilities	(57.4)	(36.8)
Fair Value Measurements on Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, Assets	17.6	33.3
Derivatives, Liabilities	(57.4)	(36.8)
Investment securities, including mutual funds	8.0	14.7
Level 1 [Member] | Fair Value Measurements on Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities, including mutual funds	5.0	4.8
Level 2 [Member] | Fair Value Measurements on Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, Assets	17.6	33.3
Derivatives, Liabilities	(57.4)	(36.8)
Investment securities, including mutual funds	$ 3.0	$ 9.9