Other - Net, (Income) Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Nonoperating Income (Expense) [Abstract]
Interest expense	$ 485.9	$ 331.6	$ 339.8
Interest income	(173.6)	(62.8)	(25.4)
Net investment (gains) losses on equity securities (Note 7)	20.2	410.7	(176.9)
Debt extinguishment loss (Note 11)	0.0	0.0	405.2
Retirement benefit plans	(461.9)	(372.9)	(289.7)
Other (income) expense	32.7	14.3	(51.4)
Other–net, (income) expense	$ (96.7)	$ 320.9	$ 201.6