Restructuring (Restructuring Liability) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Restructuring Reserve [Roll Forward]
Beginning balance	$ 6.0	$ 0.1
Expense	0.5	6.2	$ (3.7)
Utilization	(5.9)	(0.3)
Ending balance	0.6	6.0	0.1
2022 Restructuring
Restructuring Reserve [Roll Forward]
Beginning balance	6.0	0.0
Expense	0.5	6.2	0.0
Utilization	(5.9)	(0.2)
Ending balance	0.6	6.0	0.0
2020 Restructuring
Restructuring Reserve [Roll Forward]
Beginning balance	0.0	0.0
Expense	0.0	0.0	(3.6)
Utilization	0.0	0.0
Ending balance	0.0	0.0	0.0
2017 Restructuring
Restructuring Reserve [Roll Forward]
Beginning balance	0.0	0.1
Expense	0.0	0.0	(0.2)
Utilization	0.0	(0.1)
Ending balance	$ 0.0	$ 0.0	$ 0.1