Selected Quarterly Financial Data (Unaudited) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues:
Total revenues	$ 1,012.9	$ 907.3	$ 995.5	$ 896.2	$ 914.3	$ 756.6	$ 674.3	$ 593.1	$ 3,811.9	$ 2,938.3	$ 1,930.7
Cost of revenues:
Total cost of revenues	800.9	728.1	792.3	730.2	754.4	604.0	537.5	461.6	3,051.5	2,357.5	1,491.2
Selling, engineering, and administrative expenses	64.6	55.8	53.0	50.7	54.5	50.0	43.7	45.8	224.1	194.0	165.4
Gain on disposition of property, plant, and equipment	11.5	17.3	2.3	7.4	34.1	2.0	2.3	1.6	38.5	40.0	20.1
Operating profit	158.9	140.7	152.5	122.7	139.5	104.6	95.4	87.3	574.8	426.8	294.2
Net income from continuing operations	71.0	62.4	66.1	52.4	57.3	31.1	31.6	26.8	251.9	146.8	69.4
Discontinued operations, net of tax	(0.2)	0.7	1.4	(0.1)	(0.4)	0.5	0	(1.2)	1.8	(1.1)	6.0
Net income	70.8	63.1	67.5	52.3	56.9	31.6	31.6	25.6	253.7	145.7	75.4
Net income attributable to Trinity Industries, Inc.	71.3	63.2	67.8	52.9	56.1	31.9	30.0	24.2	255.2	142.2	67.4
Net income (loss) attributable to Trinity Industries, Inc. per common share:
Basic, Continuing operations (in dollars per share)	$ 0.90	$ 0.79	$ 0.82	$ 0.66	$ 0.71	$ 0.39	$ 0.37	$ 0.32	$ 3.18	$ 1.78	$ 0.77
Basic, Discontinued operations (in dollars per share)	$ 0.00	$ 0.01	$ 0.02	$ 0.00	$ (0.01)	$ 0.01	$ 0.00	$ (0.02)	$ 0.02	$ (0.01)	$ 0.08
Basic (in dollars per share)	$ 0.90	$ 0.80	$ 0.84	$ 0.66	$ 0.70	$ 0.40	$ 0.37	$ 0.30	$ 3.20	$ 1.77	$ 0.85
Diluted, Continuing operations (in dollars per share)	$ 0.90	$ 0.79	$ 0.82	$ 0.66	$ 0.71	$ 0.39	$ 0.37	$ 0.32	$ 3.17	$ 1.78	$ 0.77
Diluted, Discontinued operations (in dollars per share)	$ 0.00	$ 0.01	$ 0.02	$ 0.00	$ (0.01)	$ 0.01	$ 0.00	$ (0.02)	$ 0.02	$ (0.01)	$ 0.08
Diluted (in dollars per share)	$ 0.90	$ 0.80	$ 0.84	$ 0.66	$ 0.70	$ 0.40	$ 0.37	$ 0.30	$ 3.19	$ 1.77	$ 0.85
Manufacturing
Revenues:
Total revenues	862.2	748.0	803.2	754.1	758.3	609.2	546.1	473.3	3,167.5	2,386.9	1,466.2
Cost of revenues:
Total cost of revenues	707.7	630.7	665.8	645.7	661.2	518.3	466.8	393.0	2,649.9	2,039.3	1,236.3
Selling, engineering, and administrative expenses									143.4	127.1	111.4
Leasing
Revenues:
Total revenues	150.7	159.3	192.3	142.1	156.0	147.4	128.2	119.8	644.4	551.4	464.5
Cost of revenues:
Total cost of revenues	80.5	84.3	112.1	73.4	87.9	78.6	63.3	60.5	350.3	290.3	244.0
Selling, engineering, and administrative expenses									29.4	23.4	20.1
Other
Cost of revenues:
Total cost of revenues	12.7	13.1	14.4	11.1	5.3	7.1	7.4	8.1	51.3	27.9	10.9
Selling, engineering, and administrative expenses									$ 51.3	$ 43.5	$ 33.9