Properties, Plants, and Equipment (Components) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Gross investment, at cost	$ 2,448.0	$ 2,360.9
Less: accumulated depreciation	(1,160.1)	(1,032.9)
Total properties, plants and equipment, net	1,287.9	1,328.0
Coke and energy plant, machinery and equipment
Property, Plant and Equipment [Line Items]
Gross investment, at cost	2,077.3	2,009.3
Logistics plant, machinery and equipment
Property, Plant and Equipment [Line Items]
Gross investment, at cost	170.7	157.3
Land and land improvements
Property, Plant and Equipment [Line Items]
Gross investment, at cost	105.5	104.5
Construction-in-progress
Property, Plant and Equipment [Line Items]
Gross investment, at cost	50.8	47.4
Other
Property, Plant and Equipment [Line Items]
Gross investment, at cost	$ 43.7	$ 42.4