Employees - Financial Information Related to Pension Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	$ 140.8	$ 148.7
Interest cost	3.7	3.5	$ 4.2
Actuarial gain	(33.5)	(5.5)
Benefits paid	(5.7)	(5.6)
Other (effect of curtailment/settlement)	0.0	(0.3)
Projected benefit obligations at end of year	105.3	140.8	148.7
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	137.9	138.5
Actual gain (loss) on plan assets	(30.0)	5.0
Employer contribution	0.0	0.3
Benefits paid	(5.7)	(5.6)
Other (effect of curtailment/settlement)	0.0	(0.3)
Fair value of plan assets at end of year	102.2	137.9	$ 138.5
Under-funded status at end of year	$ (3.1)	$ (2.9)