Retirement Benefits (Details 8) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service (cost) credit	$ (8.8)	$ (9.9)
Net actuarial loss	(1,172.4)	(1,366.6)
Accumulated other comprehensive loss	(1,181.2)	(1,376.5)	$ (1,600.3)
Deferred tax effect	473.1	507.6
Accumulated other comprehensive loss, net of tax	(708.1)	(868.9)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Prior service (cost) credit	2.5	3.4
Net actuarial loss	(58.3)	(124.6)
Accumulated other comprehensive loss	(55.8)	(121.2)	$ (119.1)
Deferred tax effect	27.8	42.4
Accumulated other comprehensive loss, net of tax	$ (28.0)	$ (78.8)