Pension and Other Postretirement Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pension
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Service Cost	$ 1.7	$ 2.1	$ 4.9	$ 6.9
Interest Cost	10.2	6.9	30.4	20.4
Expected Return on Plan Assets	(10.9)	(10.4)	(32.8)	(31.1)
Amortization of Prior Service Credits	(0.1)	0.0	(0.1)	(0.1)
Amortization of Net Loss	1.4	2.8	4.3	8.6
Net Periodic Benefit Cost (Credit)	2.3	1.4	6.7	4.7
Other Postretirement
Components of Net Periodic Benefit Cost (Credit) [Abstract]
Service Cost	0.6	0.8	1.7	2.3
Interest Cost	1.6	1.1	4.6	3.3
Expected Return on Plan Assets	(2.9)	(2.4)	(8.5)	(7.2)
Amortization of Prior Service Credits	(1.8)	(1.8)	(5.3)	(5.6)
Amortization of Net Loss	(0.6)	0.1	(1.7)	0.3
Net Periodic Benefit Cost (Credit)	$ (3.1)	$ (2.2)	$ (9.2)	$ (6.9)