Supplemental Financial Information (Interest Expense) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Supplemental Income Statement Elements [Abstract]
Interest on revolving credit facility	$ 0.0	$ (3.0)	$ (0.5)	$ (6.4)
Line of credit fees	(0.3)	0.0	(0.6)	(0.3)
Debt issuance amortization costs	(0.1)	(0.1)	(0.2)	(0.4)
Interest income	0.2	0.3	0.3	0.8
Total interest expense, net	$ (0.2)	$ (2.8)	$ (1.0)	$ (6.3)