Components of Net Periodic Pension and Postretirement Benefit Expense (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Benefits, Domestic
Defined Benefit Plan Disclosure [Line Items]
Service cost			$ 0.2
Interest cost	14.6	13.3	14.5
Expected return on plan assets	(17.5)	(16.9)	(16.3)
Net actuarial gain	4.9	7.4	7.1
Net periodic cost	2.0	3.8	5.5
Curtailments and settlements	5.7
Total expense	7.7	3.8	5.5
Discount rate	4.80%	3.95%	4.50%
Expected return on plan assets	7.50%	7.75%	8.00%
Pension Benefits, Foreign
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.1	2.2	1.9
Interest cost	2.4	2.3	2.6
Expected return on plan assets	(1.4)	(1.2)	(1.4)
Prior service credit	(0.9)
Net actuarial gain	0.3	0.4	0.2
Net periodic cost	2.5	3.7	3.3
Curtailments and settlements	0.2	(0.1)
Total expense	2.7	3.6	3.3
Discount rate	3.58%	3.34%	4.30%
Expected return on plan assets	4.20%	3.98%	4.53%
Rate of compensation increase	2.50%	2.56%	2.51%
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.1	2.2	2.1
Interest cost	17.0	15.6	17.1
Expected return on plan assets	(18.9)	(18.1)	(17.7)
Prior service credit	(0.9)
Net actuarial gain	5.2	7.8	7.3
Net periodic cost	4.5	7.5	8.8
Curtailments and settlements	5.9	(0.1)
Total expense	10.4	7.4	8.8
Discount rate	4.58%	3.85%	4.47%
Expected return on plan assets	7.11%	7.32%	7.60%
Rate of compensation increase	2.50%	2.56%	2.51%
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost			0.1
Interest cost	0.3	0.3	0.3
Prior service credit	(0.3)	(0.3)	(0.4)
Net actuarial gain	(0.2)	(0.1)	(0.1)
Net periodic cost	$ (0.2)	$ (0.1)	$ (0.1)
Discount rate	4.70%	3.90%	4.40%