Selected Quarterly Financial Data (Unaudited) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Revenues:
Manufacturing	$ 785.5	$ 643.7	$ 580.1	$ 514.4	$ 516.8	$ 417.9	$ 423.5	$ 332.8	$ 2,523.7	$ 1,691.0	$ 2,050.7
Leasing	156.0	147.4	128.2	119.8	119.2	115.2	115.2	114.9	551.4	464.5	370.2
Total Revenues	941.5	791.1	708.3	634.2	636.0	533.1	538.7	447.7	3,075.1	2,155.5	2,420.9
Operating costs:
Manufacturing	686.4	548.4	498.2	431.7	451.8	348.1	351.7	283.1	2,164.7	1,434.7	1,712.5
Leasing	87.9	78.6	63.3	60.5	59.0	59.2	61.8	64.0	290.3	244.0	226.7
Other	5.3	7.1	7.4	8.1	2.6	2.1	2.1	4.1	27.9	10.9	25.7
Total cost of revenues	779.6	634.1	568.9	500.3	513.4	409.4	415.6	351.2	2,482.9	1,689.6	1,964.9
Total selling, engineering, and administrative expenses	57.8	53.5	47.5	50.3	43.7	48.7	45.5	48.4	209.1	186.3	186.1
Gain (loss) on disposition of property, plant, and equipment:
Net gains on lease fleet sales	13.1	1.6	0.4	1.1	2.3	2.3	0.3	1.7	16.2	6.6	18.4
Disposition of flood-damaged property, plant, and equipment	17.0	0.6			(0.5)	10.2			17.6	9.7
Other	4.8	(0.3)	3.1	0.8	0.3	4.4	1.0	2.2	8.4	7.9	5.8
Total gain on disposition of property, plant, and equipment	34.9	1.9	3.5	1.9	2.1	16.9	1.3	3.9	42.2	24.2	24.2
Total operating profit	139.0	105.4	95.4	85.5	81.0	91.9	78.9	52.0	425.3	303.8	(30.9)
Net income (loss)	56.9	31.6	31.6	25.6	18.5	31.5	21.1	4.3	145.7	75.4	(137.7)
Net income attributable to Trinity Industries, Inc.	$ 56.1	$ 31.9	$ 30.0	$ 24.2	$ 17.3	$ 29.7	$ 18.4	$ 2.0	$ 142.2	$ 67.4	$ (137.7)
Earnings Per Common Share
Basic	$ 0.7	$ 0.40	$ 0.37	$ 0.30	$ 0.22	$ 0.37	$ 0.23	$ 0.02	$ 1.77	$ 0.85	$ (1.81)
Diluted	$ 0.7	$ 0.40	$ 0.37	$ 0.30	$ 0.22	$ 0.37	$ 0.23	$ 0.02	$ 1.77	$ 0.85	$ (1.81)