Property, Plant, and Equipment (Details) - USD ($) $ in Millions	Sep. 30, 2015		Dec. 31, 2014
Components of property, plant, and equipment
Property, plant, and equipment	$ 7,111.0	[1]	$ 6,586.0
Less accumulated depreciation	(1,802.6)	[1]	(1,683.1)
Property, plant, and equipment, net	5,308.4	[1]	4,902.9
Partially-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	2,261.3	[1]	2,261.2
Less accumulated depreciation	(308.8)	[1]	(261.3)
Manufacturing/ Corporate
Components of property, plant, and equipment
Property, plant, and equipment	1,819.4		1,681.7
Less accumulated depreciation	(885.7)		(820.7)
Property, plant, and equipment, net	933.7		861.0
Manufacturing/ Corporate | Land
Components of property, plant, and equipment
Property, plant, and equipment	85.1		81.4
Manufacturing/ Corporate | Buildings and improvements
Components of property, plant, and equipment
Property, plant, and equipment	572.9		548.2
Manufacturing/ Corporate | Machinery and other
Components of property, plant, and equipment
Property, plant, and equipment	1,066.0		975.7
Manufacturing/ Corporate | Construction in progress
Components of property, plant, and equipment
Property, plant, and equipment	95.4		76.4
Operating segment
Components of property, plant, and equipment
Property, plant, and equipment, net	5,950.5		5,460.1
Net deferred profit on railcars sold to the Leasing Group
Components of property, plant, and equipment
Property, plant, and equipment, net	(642.1)		(557.2)
Leasing Group | Operating segment | Wholly-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	3,672.4		3,200.3
Less accumulated depreciation	(608.1)		(601.1)
Property, plant, and equipment, net	3,064.3		2,599.2
Leasing Group | Operating segment | Partially-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment, net	1,952.5		1,999.9
Leasing Group | Operating segment | Machinery and other | Wholly-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	10.7		10.7
Leasing Group | Operating segment | Equipment on lease | Wholly-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	3,661.7		3,189.6
Leasing Group | Operating segment | Equipment on lease | Partially-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	2,261.3		2,261.2
Less accumulated depreciation	$ (308.8)		$ (261.3)

[1] (unaudited)