Defined Benefit and Postretirement Benefits (Components Of Net Periodic Cost) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0.5	$ 0.6	$ 1.4	$ 1.7
Interest cost	0.5	0.2	1.6	0.6
Expected return on plan assets	(0.8)	(0.8)	(2.4)	(2.3)
Amortization of prior service cost	(0.1)	(0.1)	(0.5)	(0.5)
Amortization of net (gain) loss	0.0	0.3	0.0	0.7
Net periodic expense (benefit)	0.1	0.2	0.1	0.2
Postretirement
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.0	0.0	0.0	0.1
Interest cost	0.2	0.2	0.6	0.5
Expected return on plan assets	0.0	0.0	0.0	0.0
Amortization of prior service cost	(0.3)	(0.3)	(0.8)	(0.8)
Amortization of net (gain) loss	(0.2)	0.0	(0.5)	0.0
Net periodic expense (benefit)	$ (0.3)	$ (0.1)	$ (0.7)	$ (0.2)