Railcar Leasing and Management Services Group (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Consolidating Financial Information
Cash, cash equivalents, and short-term marketable securities	$ 498.6		$ 573.0
Property, plant, and equipment, net	5,349.9		4,861.7
Net deferred profit on railcars sold to the Leasing Group	(648.6)		(562.7)
Property, plant, and equipment, net	4,701.3	[1]	4,299.0
Restricted cash	249.3	[1]	223.2
Debt:
Less: unamortized discount	(77.6)	[1]	(87.5)
Total debt	3,021.1	[1]	3,055.0
Net deferred tax liabilities	568.3		555.8
Recourse
Debt:
Recourse	493.8		545.6
Less: unamortized discount	(77.6)		(87.5)
Total debt	416.2		458.1
Non-recourse
Debt:
Non-recourse	2,604.9		2,705.7
Less: non-recourse debt owned by Trinity			(108.8)
Partially-owned subsidiaries
Consolidating Financial Information
Restricted cash	78.8	[1]	57.8
Leasing Group
Consolidating Financial Information
Net deferred profit on railcars sold to the Leasing Group	(648.6)		(562.7)
Leasing Group | Wholly-owned subsidiaries
Consolidating Financial Information
Cash, cash equivalents, and short-term marketable securities	2.5		5.7
Property, plant, and equipment, net	2,964.6		2,773.1
Restricted cash	170.5		165.4
Debt:
Total debt	1,375.1		1,498.6
Net deferred tax liabilities	693.2		671.1
Leasing Group | Wholly-owned subsidiaries | Recourse
Debt:
Recourse	42.9		94.4
Less: unamortized discount	0		0
Total debt	42.9		94.4
Leasing Group | Wholly-owned subsidiaries | Non-recourse
Debt:
Non-recourse	1,332.2		1,404.2
Less: non-recourse debt owned by Trinity			0
Leasing Group | Partially-owned subsidiaries
Consolidating Financial Information
Cash, cash equivalents, and short-term marketable securities	0		0
Property, plant, and equipment, net	1,756.3		1,549.3
Restricted cash	78.8		57.8
Debt:
Total debt	1,272.7		1,192.7
Net deferred tax liabilities	0		5.4
Leasing Group | Partially-owned subsidiaries | Recourse
Debt:
Recourse	0		0
Less: unamortized discount	0		0
Total debt	0		0
Leasing Group | Partially-owned subsidiaries | Non-recourse
Debt:
Non-recourse	1,272.7		1,301.5
Less: non-recourse debt owned by Trinity			(108.8)
Manufacturing/Corporate
Consolidating Financial Information
Cash, cash equivalents, and short-term marketable securities	496.1		567.3
Property, plant, and equipment, net	629.0		539.3
Restricted cash	0		0
Debt:
Total debt	373.3		363.7
Net deferred tax liabilities	(124.9)		(120.7)
Manufacturing/Corporate | Recourse
Debt:
Recourse	450.9		451.2
Less: unamortized discount	(77.6)		(87.5)
Total debt	373.3		363.7
Manufacturing/Corporate | Non-recourse
Debt:
Non-recourse	0		0
Less: non-recourse debt owned by Trinity			$ 0

[1] (unaudited)