Railcar Leasing and Management Services Group (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Consolidating Financial Information
Cash, cash equivalents, and short-term marketable securities	$ 447.9		$ 573.0
Property, plant, and equipment, net	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
Restricted cash	227.0	[1]	223.2
Debt:
Less: unamortized discount	(81.0)	[1]	(87.5)
Total debt	2,884.2	[1]	3,055.0
Net deferred tax liabilities	607.7		555.8
Recourse
Debt:
Recourse	494.7		545.6
Less: unamortized discount	(81.0)		(87.5)
Total debt	413.7		458.1
Non-recourse
Debt:
Non-recourse	2,470.5		2,705.7
Less: non-recourse debt owned by Trinity			(108.8)
Partially-owned subsidiaries
Consolidating Financial Information
Restricted cash	69.1	[1]	57.8
Leasing Group | Wholly-owned subsidiaries
Consolidating Financial Information
Cash, cash equivalents, and short-term marketable securities	2.1		5.7
Property, plant, and equipment, net	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
Restricted cash	157.9		165.4
Debt:
Total debt	1,409.8		1,498.6
Net deferred tax liabilities	688.8		671.1
Leasing Group | Wholly-owned subsidiaries | Recourse
Debt:
Recourse	43.7		94.4
Less: unamortized discount	0		0
Total debt	43.7		94.4
Leasing Group | Wholly-owned subsidiaries | Non-recourse
Debt:
Non-recourse	1,366.1		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	1,526.0		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
Restricted cash	69.1		57.8
Debt:
Total debt	1,104.4		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	1,104.4		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	445.8		567.3
Property, plant, and equipment, net	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
Restricted cash	0		0
Debt:
Total debt	370.0		363.7
Net deferred tax liabilities	(81.1)		(120.7)
Manufacturing/Corporate | Recourse
Debt:
Recourse	451.0		451.2
Less: unamortized discount	(81.0)		(87.5)
Total debt	370.0		363.7
Manufacturing/Corporate | Non-recourse
Debt:
Non-recourse	0		0
Less: non-recourse debt owned by Trinity			0
Carrying Value
Debt:
Total debt	2,884.2		3,055.0
Carrying Value | Recourse
Debt:
Total debt	413.7		458.1
Carrying Value | Leasing Group | Recourse
Debt:
Total debt	43.7		94.4
Carrying Value | Leasing Group | Non-recourse
Debt:
Total debt	2,470.5		2,596.9
Carrying Value | Leasing Group | Wholly-owned subsidiaries | Non-recourse
Debt:
Total debt	1,366.1		1,404.2
Carrying Value | Leasing Group | Partially-owned subsidiaries | Non-recourse
Debt:
Total debt	1,104.4		1,192.7
Carrying Value | Manufacturing/Corporate | Recourse
Debt:
Less: unamortized discount	(81.0)		(87.5)
Total debt	$ 370.0		$ 363.7

[1] (unaudited)