Note 7. Property, Plant, and Equipment Property, Plant, and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 9,272.5	$ 8,253.4
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	2,161.9	1,919.0
Property, Plant and Equipment, Net	7,110.6	6,334.4
Manufacturing Facility, Non-Operating [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Net	13.8
Intersegment Eliminations [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	(1,135.8)	(1,030.0)
NegativeAccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	(232.0)	(202.3)
Property, Plant and Equipment, Net	(903.8)	(827.7)
Railcar Leasing and Management Services Group [Member] | Operating Segments [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Net	7,605.6	6,791.2
Manufacturing and Corporate [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,040.4	963.2
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	631.6	592.3
Property, Plant and Equipment, Net	408.8	370.9
Manufacturing and Corporate [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	28.4	24.2
Manufacturing and Corporate [Member] | Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	402.2	385.5
Manufacturing and Corporate [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	546.7	537.2
Manufacturing and Corporate [Member] | Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	63.1	16.3
Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member] | Operating Segments [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	6,957.9	5,948.3
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	1,139.0	971.8
Property, Plant and Equipment, Net	5,818.9	4,976.5
Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member] | Operating Segments [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	13.7	13.5
Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member] | Operating Segments [Member] | Equipment Leased to Other Party [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	6,944.2	5,934.8
Partially-Owned Subsidiaries [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	2,065.3	2,032.0
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	527.7	472.0
Partially-Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member] | Operating Segments [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Net	1,786.7	1,814.7
Partially-Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member] | Operating Segments [Member] | Equipment Leased to Other Party [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	2,410.0	2,371.9
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ 623.3	$ 557.2