Property, Plant, and Equipment (Details) - USD ($) $ in Millions	Mar. 31, 2016		Dec. 31, 2015
Components of property, plant, and equipment
Property, plant, and equipment	$ 7,372.2	[1]	$ 7,145.4
Less accumulated depreciation	(1,848.7)	[1]	(1,797.4)
Property, plant, and equipment, net	5,523.5	[1]	5,348.0
Partially-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	1,981.6	[1]	1,980.1
Less accumulated depreciation	(327.6)	[1]	(313.7)
Manufacturing/ Corporate
Components of property, plant, and equipment
Property, plant, and equipment	1,870.8		1,861.5
Less accumulated depreciation	(920.3)		(905.4)
Property, plant, and equipment, net	950.5		956.1
Manufacturing/ Corporate | Land
Components of property, plant, and equipment
Property, plant, and equipment	88.8		86.5
Manufacturing/ Corporate | Buildings and improvements
Components of property, plant, and equipment
Property, plant, and equipment	617.4		610.4
Manufacturing/ Corporate | Machinery and other
Components of property, plant, and equipment
Property, plant, and equipment	1,102.4		1,095.9
Manufacturing/ Corporate | Construction in progress
Components of property, plant, and equipment
Property, plant, and equipment	62.2		68.7
Operating Segments
Components of property, plant, and equipment
Property, plant, and equipment, net	6,254.3		6,021.0
Operating Segments | Leasing Group | Wholly-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	4,053.4		3,774.2
Less accumulated depreciation	(673.3)		(647.9)
Property, plant, and equipment, net	3,380.1		3,126.3
Operating Segments | Leasing Group | Partially-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment, net	1,923.7		1,938.6
Operating Segments | Machinery and other | Leasing Group | Wholly-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	10.7		10.7
Operating Segments | Equipment on lease | Leasing Group | Wholly-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	4,042.7		3,763.5
Operating Segments | Equipment on lease | Leasing Group | Partially-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	2,309.1		2,307.7
Less accumulated depreciation	(385.4)		(369.1)
Net deferred profit on railcars sold to the Leasing Group
Components of property, plant, and equipment
Property, plant, and equipment, net	$ (730.8)		$ (673.0)

[1] (unaudited)