Retirement Plans, Postretirement and Postemployment Benefits - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation for defined benefit pension plans	$ 881.9	$ 789.6
Combined pension plan and SERP contributions	31.8	90.2
Estimated contribution of pension plans	32.7
Corporation's matching obligations	$ 22.3	$ 23.1	$ 20.5
Defined contribution plan name	401(a)
Defined benefit plans remeasurement increased	$ 47.6
Postretirement Health Care Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated contribution of pension plans	$ 1.0