Pensions and Postretirement Benefits Other Than Pensions (Schedule of Company's Postretirement Plans Benefit Obligations) (Details) - Postretirement [Member] - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021
Benefit obligation at beginning of year		$ 342.2	$ 389.1
Service cost		1.8	2.1
Interest cost		6.9	5.5
Plan participants' contributions		5.7	5.6
Actuarial (gains) losses		(53.7)	(22.2)
Benefits paid, net of Medicare Part D subsidy	[1]	(39.8)	(37.8)
Other, including expenses paid		0.0	(0.1)
Benefit obligation at end of year		$ 266.4	$ 342.2

[1] Actuarial (gains) losses primarily resulted from changes in discount rates. (2) Amounts are net of Medicare Part D subsidy of $0.4 million and $0.5 million in 2022 and 2021, respectively.