Pension Plans (Other Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Actual return on pension plan assets	17.60%
Maximize return	42.30%
Liquidity	57.70%
Defined contribution, maximum contribution limit	5.00%
Qualified Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	6.50%	7.50%
Managers’ securities holdings percentage maximum limit of total market value	7.50%
Continuing Operations [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer contributions	$ 6.7	$ 7.1	$ 6.8
Discontinued Operations, Disposed of by Sale [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, employer contributions	0.0	$ 4.5	$ 6.3
Pension Costs [Member]
Payment for Pension and Other Postretirement Benefits [Abstract]
Accrual for payments due to customer under agreement	$ 0.3