Postretirement Benefits (Obligations and Funded Status) (Details) - Pension Plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Change in plan assets:
Fair value of plan assets as of January 1	$ 26.7	$ 26.3
Actual return on plan assets	0.4	1.9
Settlements	0.0	(0.3)
Employer contributions	0.0	0.3
Benefit payments	(1.7)	(1.5)
Fair value of plan assets as of December 31	25.4	26.7	$ 26.3
Change in plan benefit obligations:
Fair value of plan benefit obligations as of January 1	21.4	21.3
Interest cost	1.0	1.1	0.7
Actuarial (gain) loss	(1.7)	0.8
Settlements	0.0	(0.3)
Benefit payments	(1.7)	(1.5)
Fair value of plan benefit obligations as of December 31	19.0	21.4	$ 21.3
Amount overfunded	$ 6.4	$ 5.3