Railcar Leasing and Management Services Group (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Consolidating Financial Information
Cash and cash equivalents	$ 312.2		$ 351.1
Property, plant, and equipment, net	4,819.0		4,711.0
Net deferred profit on railcars sold to the Leasing Group	(535.3)		(531.5)
Property, plant and equipment, net	4,283.7	[1]	4,179.5
Restricted cash	234.8	[1]	240.3
Debt:
Less: unamortized discount	(90.7)	[1]	(99.8)
Total debt	2,978.1	[1]	2,974.9
Net deferred tax liabilities	543.0	[1]	434.7
Recourse
Debt:
Recourse	553.0		557.5
Less: unamortized discount	(90.7)		(99.8)
Total debt	462.3		457.7
Non-Recourse
Debt:
Non-recourse	2,624.6		2,626.0
Less: non-recourse debt owned by Trinity	(108.8)		(108.8)
TRIP Holdings
Consolidating Financial Information
Restricted cash	59.0	[1]	74.6
Leasing Group | Wholly-owned subsidiaries
Consolidating Financial Information
Cash and cash equivalents	5.0		3.2
Property, plant, and equipment, net	3,175.3		3,066.0
Net deferred profit on railcars sold to the Leasing Group	(352.8)		(344.5)
Property, plant and equipment, net	2,822.5		2,721.5
Restricted cash	175.8		165.7
Debt:
Total debt	1,744.8		1,719.3
Net deferred tax liabilities	622.4		582.4
Leasing Group | Wholly-owned subsidiaries | Recourse
Debt:
Recourse	97.9		103.3
Less: unamortized discount	0		0
Total debt	97.9		103.3
Leasing Group | Wholly-owned subsidiaries | Non-Recourse
Debt:
Non-recourse	1,646.9		1,616.0
Less: non-recourse debt owned by Trinity	0		0
Leasing Group | TRIP Holdings
Consolidating Financial Information
Cash and cash equivalents	0		0
Property, plant, and equipment, net	1,127.1		1,135.0
Net deferred profit on railcars sold to the Leasing Group	(182.5)		(187.0)
Property, plant and equipment, net	944.6		948.0
Restricted cash	59.0		74.6
Debt:
Total debt	868.9		901.2
Net deferred tax liabilities	5.1		4.7
Leasing Group | TRIP Holdings | Recourse
Debt:
Recourse	0		0
Less: unamortized discount	0		0
Total debt	0		0
Leasing Group | TRIP Holdings | Non-Recourse
Debt:
Non-recourse	977.7		1,010.0
Less: non-recourse debt owned by Trinity	(108.8)		(108.8)
Manufacturing/Corporate
Consolidating Financial Information
Cash and cash equivalents	307.2		347.9
Property, plant, and equipment, net	516.6		510.0
Net deferred profit on railcars sold to the Leasing Group	0		0
Property, plant and equipment, net	516.6		510.0
Restricted cash	0		0
Debt:
Total debt	364.4		354.4
Net deferred tax liabilities	(84.5)		(152.4)
Manufacturing/Corporate | Recourse
Debt:
Recourse	455.1		454.2
Less: unamortized discount			(99.8)
Total debt	364.4		354.4
Manufacturing/Corporate | Non-Recourse
Debt:
Non-recourse	0		0
Less: non-recourse debt owned by Trinity	0		0
Carrying Value
Debt:
Total debt	2,978.1		2,974.9
Carrying Value | Recourse
Debt:
Total debt	462.3		457.7
Carrying Value | Leasing Group | Non-Recourse
Debt:
Total debt	2,515.8		2,517.2
Carrying Value | Leasing Group | Wholly-owned subsidiaries | Recourse
Debt:
Total debt	97.9		103.3
Carrying Value | Manufacturing/Corporate | Recourse
Debt:
Less: unamortized discount	(90.7)		(99.8)
Total debt	$ 364.4		$ 354.4

[1] (unaudited)