Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Financial Information from continuing operations for segments
Revenues	$ 1,661.4	$ 1,562.8	$ 1,485.3	$ 1,460.5	$ 1,256.0	$ 1,110.3	$ 1,066.1	$ 932.9	$ 6,170.0		$ 4,365.3		$ 3,811.9
Operating Profit (Loss)	276.5	281.2	302.0	391.3	224.4	205.6	183.4	159.5	1,251.0		772.9		574.8
Assets	8,733.8				7,313.4				8,733.8		7,313.4		6,642.0
Depreciation & Amortization									244.6		211.5		193.7
Capital Expenditures									464.6		731.0		469.2
Rail Group
Financial Information from continuing operations for segments
Revenues									3,077.6		2,093.5		1,512.1
Operating Profit (Loss)									724.1		489.7		199.0
Assets	1,322.4				1,063.9				1,322.4		1,063.9		916.2
Depreciation & Amortization									32.7		27.2		21.8
Capital Expenditures									98.3		42.4		47.8
Construction Products Group
Financial Information from continuing operations for segments
Revenues									546.1		508.6		461.2
Operating Profit (Loss)									65.4		52.6		44.8
Assets	459.3				459.9				459.3		459.9		415.2
Depreciation & Amortization									22.7		20.9		16.6
Capital Expenditures									37.1		17.1		15.7
Inland Barge Group
Financial Information from continuing operations for segments
Revenues									638.5		576.6		675.2
Operating Profit (Loss)									114.4		96.0		124.7
Assets	177.1				170.3				177.1		170.3		154.4
Depreciation & Amortization									9.3		8.1		7.6
Capital Expenditures									9.7		18.4		15.0
Energy Equipment Group
Financial Information from continuing operations for segments
Revenues									796.0		536.5		506.0
Operating Profit (Loss)									108.1		61.4		18.2
Assets	1,160.0				364.3				1,160.0		364.3		400.1
Depreciation & Amortization									33.0		18.2		19.0
Capital Expenditures									56.0		41.5		25.2
Railcar Leasing and Management Services Group
Financial Information from continuing operations for segments
Revenues									1,106.4		645.4		644.4
Operating Profit (Loss)									516.3		296.8		300.9
Assets	4,972.1				5,026.9				4,972.1		5,026.9		4,538.8
Depreciation & Amortization									130.0	[1]	129.0	[1]	120.5	[1]
Capital Expenditures									245.3		581.1		352.6
All Other
Financial Information from continuing operations for segments
Revenues									5.4		4.7		13.0
Operating Profit (Loss)									(25.6)		(13.7)		(10.2)
Assets	56.3				49.8				56.3		49.8		30.9
Depreciation & Amortization									9.6		3.7		4.4
Capital Expenditures									9.3		4.4		6.6
Segment Totals before Eliminations and Corporate
Financial Information from continuing operations for segments
Revenues									6,170.0		4,365.3		3,811.9
Operating Profit (Loss)									1,502.7		982.8		677.4
Assets	8,147.2				7,135.1				8,147.2		7,135.1		6,455.6
Depreciation & Amortization									237.3		207.1		189.9
Capital Expenditures									455.7		704.9		462.9
Corporate
Financial Information from continuing operations for segments
Revenues									0		0		0
Operating Profit (Loss)									(119.0)		(73.4)		(51.5)
Assets	1,147.1				731.0				1,147.1		731.0		744.9
Depreciation & Amortization									7.4		4.5		3.9
Capital Expenditures									8.9		26.1		6.3
Eliminations – Lease subsidiary
Financial Information from continuing operations for segments
Revenues									0		0		0
Operating Profit (Loss)									(133.1)		(135.4)		(50.8)
Assets	(557.2)				(549.7)				(557.2)		(549.7)		(446.2)
Depreciation & Amortization									0		0		0
Capital Expenditures									0		0		0
Eliminations – Other
Financial Information from continuing operations for segments
Revenues									0		0		0
Operating Profit (Loss)									0.4		(1.1)		(0.3)
Assets	(3.3)				(3.0)				(3.3)		(3.0)		(112.3)
Depreciation & Amortization									(0.1)		(0.1)		(0.1)
Capital Expenditures									0		0		0
Intersegment
Financial Information from continuing operations for segments
Revenues									0		0		0
Intersegment | Rail Group
Financial Information from continuing operations for segments
Revenues									739.2		774.0		500.9
Intersegment | Construction Products Group
Financial Information from continuing operations for segments
Revenues									5.6		16.4		22.5
Intersegment | Inland Barge Group
Financial Information from continuing operations for segments
Revenues									0		0.1		0
Intersegment | Energy Equipment Group
Financial Information from continuing operations for segments
Revenues									196.3		128.9		52.6
Intersegment | Railcar Leasing and Management Services Group
Financial Information from continuing operations for segments
Revenues									11.9		0		2.7
Intersegment | All Other
Financial Information from continuing operations for segments
Revenues									105.0		81.9		68.4
Intersegment | Segment Totals before Eliminations and Corporate
Financial Information from continuing operations for segments
Revenues									1,058.0		1,001.3		647.1
Intersegment | Corporate
Financial Information from continuing operations for segments
Revenues									0		0		0
Intersegment | Eliminations – Lease subsidiary
Financial Information from continuing operations for segments
Revenues									(710.1)		(756.5)		(485.9)
Intersegment | Eliminations – Other
Financial Information from continuing operations for segments
Revenues									(347.9)		(244.8)		(161.2)
Total
Financial Information from continuing operations for segments
Revenues									6,170.0		4,365.3		3,811.9
Total | Rail Group
Financial Information from continuing operations for segments
Revenues									3,816.8		2,867.5		2,013.0
Total | Construction Products Group
Financial Information from continuing operations for segments
Revenues									551.7		525.0		483.7
Total | Inland Barge Group
Financial Information from continuing operations for segments
Revenues									638.5		576.7		675.2
Total | Energy Equipment Group
Financial Information from continuing operations for segments
Revenues									992.3		665.4		558.6
Total | Railcar Leasing and Management Services Group
Financial Information from continuing operations for segments
Revenues									1,118.3		645.4		647.1
Operating Profit (Loss)									516.3		296.8		300.9
Total | All Other
Financial Information from continuing operations for segments
Revenues									110.4		86.6		81.4
Total | Segment Totals before Eliminations and Corporate
Financial Information from continuing operations for segments
Revenues									7,228.0		5,366.6		4,459.0
Total | Corporate
Financial Information from continuing operations for segments
Revenues									0		0		0
Total | Eliminations – Lease subsidiary
Financial Information from continuing operations for segments
Revenues									(710.1)		(756.5)		(485.9)
Total | Eliminations – Other
Financial Information from continuing operations for segments
Revenues									$ (347.9)		$ (244.8)		$ (161.2)

[1] Depreciation, maintenance, and rent expense are components of operating profit. Amortization of deferred profit on railcars sold from the Rail Group to the Leasing Group is included in the operating profit of the Leasing Group resulting in the recognition of depreciation expense based on the Company's original manufacturing cost of the railcars. Interest expense is not a component of operating profit and includes the effect of hedges. Intercompany interest expense is eliminated in consolidation and arises from Trinity’s previous ownership of a portion of TRIP Holdings’ Senior Secured Notes, which notes were retired in full in May 2013. See Note 11 Debt.