Property, Plant, and Equipment (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Components of property, plant, and equipment
Less accumulated depreciation	$ (1,441.8)	[1]	$ (1,343.0)
Property, plant, and equipment, net before adjustment to net deferred profit	5,197.2		4,861.7
Net deferred profit on railcars sold to the Leasing Group	(612.6)		(562.7)
Property, plant, and equipment, net	4,584.6	[1]	4,299.0
Partially-owned subsidiaries
Components of property, plant, and equipment
Less accumulated depreciation	(177.0)	[1]	(153.8)
Manufacturing/Corporate
Components of property, plant, and equipment
Property, plant and equipment	1,362.9		1,260.1
Less accumulated depreciation	(752.5)		(720.8)
Property, plant, and equipment, net before adjustment to net deferred profit	610.4		539.3
Net deferred profit on railcars sold to the Leasing Group	0		0
Property, plant, and equipment, net	610.4		539.3
Leasing Group | Wholly-owned subsidiaries
Components of property, plant, and equipment
Property, plant and equipment	3,573.1		3,241.5
Less accumulated depreciation	(512.3)		(468.4)
Property, plant, and equipment, net before adjustment to net deferred profit	3,060.8		2,773.1
Net deferred profit on railcars sold to the Leasing Group	(376.5)		(381.8)
Property, plant, and equipment, net	2,684.3		2,391.3
Leasing Group | Partially-owned subsidiaries
Components of property, plant, and equipment
Property, plant, and equipment, net before adjustment to net deferred profit	1,526.0		1,549.3
Net deferred profit on railcars sold to the Leasing Group	(236.1)		(180.9)
Property, plant, and equipment, net	1,289.9		1,368.4
Land | Manufacturing/Corporate
Components of property, plant, and equipment
Property, plant and equipment	40.9		37.7
Buildings and improvements | Manufacturing/Corporate
Components of property, plant, and equipment
Property, plant and equipment	442.1		431.0
Machinery and other | Manufacturing/Corporate
Components of property, plant, and equipment
Property, plant and equipment	832.0		745.3
Machinery and other | Leasing Group | Wholly-owned subsidiaries
Components of property, plant, and equipment
Property, plant and equipment	9.8		9.6
Construction in progress | Manufacturing/Corporate
Components of property, plant, and equipment
Property, plant and equipment	47.9		46.1
Equipment on lease | Leasing Group | Wholly-owned subsidiaries
Components of property, plant, and equipment
Property, plant and equipment	3,563.3		3,231.9
Equipment on lease | Leasing Group | Partially-owned subsidiaries
Components of property, plant, and equipment
Property, plant and equipment	1,703.0		1,703.1
Less accumulated depreciation	$ (177.0)		$ (153.8)

[1] (unaudited)