Components of Net Periodic Pension Cost (Detail) - Pension Plans, Defined Benefit - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost, net of employee contributions	$ 7.5	$ 6.8	$ 15.0	$ 13.5
Interest cost	4.9	5.2	9.9	10.5
Expected return on plan assets	(7.8)	(6.8)	(15.6)	(13.6)
Amortization	2.9	2.5	5.8	4.9
Net periodic pension cost	$ 7.5	$ 7.7	$ 15.1	$ 15.3