Benefit Plans, Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Change in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income [Abstract]
Amortization of prior service credit (gain) loss	$ (3.7)	$ (8.4)	$ (10.0)
Total recognized in other comprehensive income	(35.3)	(45.2)	$ 18.7
Pension Benefits [Member]
Change in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income [Abstract]
Current year actuarial gain (loss)	31.2	36.7
Amortization of actuarial (gain) loss	4.0	9.0
Total recognized in other comprehensive income	35.2	45.7
Post-Retirement Benefits [Member]
Change in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income [Abstract]
Current year actuarial gain (loss)	0.4	0.1
Amortization of actuarial (gain) loss	(0.3)	(0.6)
Total recognized in other comprehensive income	$ 0.1	$ (0.5)