Retirement Plans, Postretirement and Postemployment Benefits - Change in Projected Benefit Obligation (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension
Defined Benefit Plan Disclosure [Line Items]
Net projected benefit obligation at beginning of year	$ 1,135.5	$ 1,111.9
Service cost	48.1	46.2	$ 39.2
Interest cost	41.2	35.7	37.1
Actuarial (gain) loss	(363.3)	(16.2)
Gross benefits paid	(52.0)	(42.1)
Plan amendments	48.1
Net projected benefit obligation at end of year	857.6	1,135.5	1,111.9
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net projected benefit obligation at beginning of year	11.4	12.6
Interest cost	0.4	0.3	0.4
Participants' contributions	0.6	0.6
Actuarial (gain) loss	(1.9)	(0.6)
Gross benefits paid	(1.6)	(1.5)
Net projected benefit obligation at end of year	$ 8.9	$ 11.4	$ 12.6