Components of Change in Projected Benefit Obligation and Change in Plan Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Change in projected benefit obligation:
Benefit obligation, beginning balance	$ 2,567.0	$ 3,709.6
Service cost	94.0	148.5	$ 148.4
Interest cost	$ 127.5	$ 84.9	65.3
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]	Costs and Expenses	Costs and Expenses
Benefits paid	$ (110.1)	$ (107.7)
Actuarial loss (gain)	186.5	(1,190.4)
Currency translation and other	37.8	(78.3)
Participant contributions	0.6	0.4
Projected benefit obligation, ending balance	2,903.3	2,567.0	3,709.6
Change in plan assets:
Fair value of plan assets, beginning balance	3,115.2	4,094.5
Employer contributions	27.3	39.1
Actual gain (loss) on plan assets	412.5	(809.6)
Benefits paid	(110.1)	(107.7)
Currency translation and other	48.6	(101.5)
Participant contributions	0.6	0.4
Fair value of plan assets, ending balance	3,494.1	3,115.2	$ 4,094.5
Funded status, ending balance	590.8	548.2
Amounts recorded on Balance Sheets:
Other noncurrent assets	734.8	671.2
Accounts payable, accrued expenses and other	23.8	18.0
Other liabilities	120.2	105.0
Accumulated other comprehensive loss:
Actuarial loss	98.0	97.9
Prior service cost	$ 12.3	$ 13.0