Property, Plant, and Equipment - Components of property, plant, and equipment (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,920.5 and $1,927.7	$ 9,244.8	$ 9,105.6
Less: accumulated depreciation	(2,351.0)	(2,258.7)
Property, Plant and Equipment, Net	6,893.8	6,846.9
Intersegment Eliminations [Member]
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,920.5 and $1,927.7	(1,057.5)	(1,047.3)
NegativeAccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	283.1	268.2
Property, Plant and Equipment, Net	(774.4)	(779.1)
Railcar Leasing and Management Services Group [Member] | Operating Segments [Member]
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment, Net	7,326.6	7,276.7
Manufacturing and Corporate [Member]
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,920.5 and $1,927.7	822.7	828.0
Less: accumulated depreciation	(481.1)	(478.7)
Property, Plant and Equipment, Net	341.6	349.3
Manufacturing and Corporate [Member] | Land
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,920.5 and $1,927.7	15.8	17.4
Manufacturing and Corporate [Member] | Buildings and improvements
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,920.5 and $1,927.7	385.0	377.4
Manufacturing and Corporate [Member] | Machinery and other
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,920.5 and $1,927.7	406.0	415.1
Manufacturing and Corporate [Member] | Construction in progress
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,920.5 and $1,927.7	15.9	18.1
Wholly-owned subsidiaries | Railcar Leasing and Management Services Group [Member] | Operating Segments [Member]
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,920.5 and $1,927.7	7,245.1	7,082.0
Less: accumulated depreciation	(1,452.0)	(1,375.9)
Property, Plant and Equipment, Net	5,793.1	5,706.1
Wholly-owned subsidiaries | Railcar Leasing and Management Services Group [Member] | Machinery and other | Operating Segments [Member]
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,920.5 and $1,927.7	21.6	20.7
Wholly-owned subsidiaries | Railcar Leasing and Management Services Group [Member] | Equipment on lease | Operating Segments [Member]
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,920.5 and $1,927.7	7,223.5	7,061.3
Partially-owned subsidiaries
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,920.5 and $1,927.7	1,920.5	1,927.7
Less: accumulated depreciation	(591.8)	(568.4)
Partially-owned subsidiaries | Railcar Leasing and Management Services Group [Member] | Operating Segments [Member]
Property, Plant and Equipment, Net [Abstract]
Less: accumulated depreciation	(701.0)	(672.3)
Property, Plant and Equipment, Net	1,533.5	1,570.6
Partially-owned subsidiaries | Railcar Leasing and Management Services Group [Member] | Equipment on lease | Operating Segments [Member]
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,920.5 and $1,927.7	$ 2,234.5	$ 2,242.9