Pension and Postretirement Benefit Plans (Net Pension And Postretirement Cost) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pension benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2.1	$ 2.4
Interest cost	7.0	7.2
Expected return on plan assets	(7.7)	(7.2)
Amortization of net actuarial losses	2.2	2.0
Amortization of prior service cost	0.3	0.3
Net periodic cost	3.9	4.7
Postretirement benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.1	0.0
Interest cost	0.4	0.3
Amortization of prior service cost	0.1	0.1
Net periodic cost	$ 0.6	$ 0.4