Note 7. Property, Plant, and Equipment Property, Plant, and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2020		Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	$ 9,193.0		$ 9,272.5
Less accumulated depreciation, including partially-owned subsidiaries of $525.7 and $527.7	2,189.6		2,161.9
Property, Plant and Equipment, Net	7,003.4		7,110.6
Manufacturing Facility, Non-Operating [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Net	12.4
Intersegment Eliminations [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	(1,064.7)		(1,135.8)
NegativeAccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	244.4		232.0
Property, Plant and Equipment, Net	(820.3)		(903.8)
Railcar Leasing and Management Services Group [Member] | Operating Segments [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Net	7,422.2	[1]	7,605.6
Manufacturing and Corporate [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	979.4		1,040.4
Less accumulated depreciation, including partially-owned subsidiaries of $525.7 and $527.7	577.9		631.6
Property, Plant and Equipment, Net	401.5		408.8
Manufacturing and Corporate [Member] | Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	23.2		28.4
Manufacturing and Corporate [Member] | Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	428.6		402.2
Manufacturing and Corporate [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	485.1		546.7
Manufacturing and Corporate [Member] | Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	42.5		63.1
Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member] | Operating Segments [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	7,030.1		6,957.9
Less accumulated depreciation, including partially-owned subsidiaries of $525.7 and $527.7	1,234.2		1,139.0
Property, Plant and Equipment, Net	5,795.9	[1]	5,818.9
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, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	19.5		13.7
Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member] | Operating Segments [Member] | Railcars on Lease [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	7,010.6		6,944.2
Partially-Owned Subsidiaries [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	1,931.6		2,065.3
Less accumulated depreciation, including partially-owned subsidiaries of $525.7 and $527.7	525.7		527.7
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	1,626.3	[1]	1,786.7
Partially-Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member] | Operating Segments [Member] | Railcars on Lease [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, at cost, including partially-owned subsidiaries of $1,931.6 and $2,065.3	2,248.2		2,410.0
Less accumulated depreciation, including partially-owned subsidiaries of $525.7 and $527.7	$ 621.9		$ 623.3

[1] See Note 11 for further information regarding impairment of long-lived assets recorded in the year ended December 31, 2020