Retirement and Employee Benefit Plans (Amounts Recognized in Other Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Total change in value of pension and postretirement liabilities	$ 13.0	$ (5.0)	$ 3.0
Pension benefit, tax effects	2.7
Other postretirement benefit, tax effects	0.4
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (loss) gain arising during the year	5.0	(12.0)
Amortization of prior service cost	0.0	0.0
Amortization of net loss	1.0	1.0
Settlements	5.0	0.0
Curtailments	0.0	3.0
Less: Tax effect (1)	0.0	3.0
Total change in value of pension and postretirement liabilities	11.0	(5.0)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (loss) gain arising during the year	2.0	2.0
Amortization of prior service cost	0.0	0.0
Amortization of net loss	0.0	0.0
Settlements	0.0	0.0
Curtailments	0.0	0.0
Less: Tax effect (1)	0.0	(1.0)
Total change in value of pension and postretirement liabilities	$ 2.0	$ 1.0