Components of Net Periodic Pension Cost (Detail) - Pension Plans, Defined Benefit - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost, net of employee contributions	$ 7.3	$ 7.5
Interest cost	4.7	5.0
Expected return on plan assets	(8.1)	(7.8)
Amortization	2.6	2.9
Net periodic pension cost	$ 6.5	$ 7.6