Property, Plant, and Equipment (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Components of property, plant, and equipment
Less accumulated depreciation	$ (1,721.4)	[1]	$ (1,683.1)
Property, plant, and equipment, net before adjustment to net deferred profit	5,733.1		5,460.1
Net deferred profit on railcars sold to the Leasing Group	(584.2)		(557.2)
Property, plant, and equipment, net	5,148.9	[1]	4,902.9
Partially-owned subsidiaries
Components of property, plant, and equipment
Less accumulated depreciation	(277.2)	[1]	(261.3)
Manufacturing/Corporate
Components of property, plant, and equipment
Property, plant, and equipment	1,755.0		1,681.7
Less accumulated depreciation	(838.6)		(820.7)
Property, plant, and equipment, net before adjustment to net deferred profit	916.4		861.0
Leasing Group
Components of property, plant, and equipment
Net deferred profit on railcars sold to the Leasing Group	(584.2)		(557.2)
Leasing Group | Wholly-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	3,438.9		3,200.3
Less accumulated depreciation	(605.6)		(601.1)
Property, plant, and equipment, net before adjustment to net deferred profit	2,833.3		2,599.2
Leasing Group | Partially-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment, net before adjustment to net deferred profit	1,983.4		1,999.9
Land | Manufacturing/Corporate
Components of property, plant, and equipment
Property, plant, and equipment	88.6		81.4
Buildings and improvements | Manufacturing/Corporate
Components of property, plant, and equipment
Property, plant, and equipment	557.2		548.2
Machinery and other | Manufacturing/Corporate
Components of property, plant, and equipment
Property, plant, and equipment	1,020.3		975.7
Machinery and other | Leasing Group | Wholly-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	10.7		10.7
Construction in progress | Manufacturing/Corporate
Components of property, plant, and equipment
Property, plant, and equipment	88.9		76.4
Equipment on lease | Leasing Group | Wholly-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	3,428.2		3,189.6
Equipment on lease | Leasing Group | Partially-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment	2,260.6		2,261.2
Less accumulated depreciation	$ (277.2)		$ (261.3)

[1] (unaudited)