Retirement Plans, Postretirement and Postemployment Benefits - Net Periodic Benefit Cost Recognized in Comprehensive Earnings (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss	$ (67.5)	$ 34.7	$ 11.7
Net prior service cost (credit)			6.4
Prior service (cost) credit	(0.8)	(0.7)
Actuarial gain (loss)	(12.2)	(14.5)	(16.0)
Settlement (charge) credit		(3.7)
Total	(80.5)	15.8	2.1
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Actuarial (gain) loss	(0.6)	0.5	1.0
Prior service (cost) credit	0.8	0.8	0.8
Actuarial gain (loss)	0.1	0.2	0.5
Total	$ 0.3	$ 1.5	$ 2.3