Employee Retirement Plans (Reconciliation of Projected Benefit Obligation, Fair Value of Plan Assets, and Funded Status) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Changes in benefit obligation
Projected benefit obligation, beginning of year	$ (525.6)	$ (515.7)
Interest cost	(8.8)	(13.6)
Actuarial gain (loss)	23.1	(40.5)
Benefits paid	47.5	43.6
Liability benefit from settlement	1.1	0.6
Projected benefit obligation, end of year	(462.7)	(525.6)
Changes in plan assets
Fair value of plan assets, beginning of year	469.0	436.8
Actual return on plan assets	20.4	68.0
Employer contributions	1.6	7.8
Benefits paid	(47.5)	(43.6)
Fair value of plan assets, end of year	443.5	469.0
Funded status
Funded status	(19.2)	$ (56.6)
Net underfunded benefit plan obligations decrease	$ (37.4)
Defined benefit plan, actual return on plan assets	5.11%