Defined Benefit Pension Plans - Components of Net Periodic Defined Benefit Pension Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1.5	$ 2.9	$ 3.1	$ 5.9
Interest cost	5.5	3.0	11.1	6.2
Expected return on plan assets	(5.2)	(3.4)	(10.4)	(6.9)
Recognized net actuarial losses	1.0	3.7	1.9	7.5
Settlements	6.2		6.2
Total	9.0	$ 6.2	$ 11.9	$ 12.7
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Settlements	$ 6.2