Property, Plant, and Equipment - Components of property, plant, and equipment (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,909.9 and $1,927.7	$ 9,278.2	$ 9,105.6
Less: accumulated depreciation	(2,334.1)	(2,258.7)
Property, Plant and Equipment, Net	6,944.1	6,846.9
Intersegment Eliminations [Member]
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,909.9 and $1,927.7	(1,062.0)	(1,047.3)
NegativeAccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	280.4	268.2
Property, Plant and Equipment, Net	(781.6)	(779.1)
Railcar Leasing and Management Services Group [Member] | Operating Segments [Member]
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment, Net	7,379.2	7,276.7
Manufacturing and Corporate [Member]
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,909.9 and $1,927.7	832.6	828.0
Less: accumulated depreciation	(486.1)	(478.7)
Property, Plant and Equipment, Net	346.5	349.3
Manufacturing and Corporate [Member] | Land
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,909.9 and $1,927.7	16.3	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 $1,909.9 and $1,927.7	385.2	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 $1,909.9 and $1,927.7	410.9	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 $1,909.9 and $1,927.7	20.2	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 $1,909.9 and $1,927.7	7,284.4	7,082.0
Less: accumulated depreciation	(1,440.0)	(1,375.9)
Property, Plant and Equipment, Net	5,844.4	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 $1,909.9 and $1,927.7	22.0	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 $1,909.9 and $1,927.7	7,262.4	7,061.3
Partially-owned subsidiaries
Property, Plant and Equipment, Net [Abstract]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,909.9 and $1,927.7	1,909.9	1,927.7
Less: accumulated depreciation	(581.3)	(568.4)
Partially-owned subsidiaries | Railcar Leasing and Management Services Group [Member] | Operating Segments [Member]
Property, Plant and Equipment, Net [Abstract]
Less: accumulated depreciation	(688.4)	(672.3)
Property, Plant and Equipment, Net	1,534.8	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 $1,909.9 and $1,927.7	$ 2,223.2	$ 2,242.9