Employees - Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Retirement Benefits [Abstract]
Interest cost	$ 5.3	$ 3.7	$ 3.5
Expected return on plan assets	(5.4)	(5.2)	(6.0)
Amortization of net gain	(0.1)	0.0	0.0
Net periodic benefit	$ (0.2)	$ (1.5)	$ (2.5)