Earnings Per Common Share (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
Net Income Per Common Share (Textual) [Abstract]
Total weighted average restricted shares and antidilutive stock options, number of shares									3.1	3.0	2.8
Computation of basic and diluted net income attributable to Trinity Industries, Inc
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
Less: net income (loss) from continuing operations attributable to noncontrolling interest									(1.5)	3.5	8.0
Net income from continuing operations attributable to Trinity Industries, Inc.									253.4	143.3	61.4
Unvested restricted share participation									(7.7)	(5.0)	(2.1)
Net income attributable to Trinity Industries, Inc. - basic									245.7	138.3	59.3
Net income attributable to Trinity Industries, Inc. - basic, Average Shares									77.3	77.5	76.8
Net income from continuing operations attributable to Trinity Industries, Inc. - basic, EPS	$ 0.90	$ 0.79	$ 0.82	$ 0.66	$ 0.71	$ 0.39	$ 0.37	$ 0.32	$ 3.18	$ 1.78	$ 0.77
Effect of dilutive securities:
Stock options, Income (Loss)									0	0	0
Stock options, Average Shares									0.2	0.3	0.2
Net income from continuing operations attributable to Trinity Industries, Inc. - diluted									245.7	138.3	59.3
Net income from continuing operations attributable to Trinity Industries, Inc. - diluted, Average Shares									77.5	77.8	77.0
Net income from continuing operations attributable to Trinity Industries, Inc. - diluted, EPS	$ 0.90	$ 0.79	$ 0.82	$ 0.66	$ 0.71	$ 0.39	$ 0.37	$ 0.32	$ 3.17	$ 1.78	$ 0.77
Net income (loss) from discontinued operations, net of taxes	(0.2)	0.7	1.4	(0.1)	(0.4)	0.5	0	(1.2)	1.8	(1.1)	6.0
Unvested restricted share participation									(0.1)	0	(0.2)
Net income from discontinued operations, net of taxes - basic, Income (Loss)									1.7	(1.1)	5.8
Net income (loss) from discontinued operations, net of taxes - basic, EPS	$ 0.00	$ 0.01	$ 0.02	$ 0.00	$ (0.01)	$ 0.01	$ 0.00	$ (0.02)	$ 0.02	$ (0.01)	$ 0.08
Net income from discontinued operations, net of taxes - diluted, Income (Loss)									$ 1.7	$ (1.1)	$ 5.8
Net income (loss) from discontinued operations, net of taxes - diluted, EPS	$ 0.00	$ 0.01	$ 0.02	$ 0.00	$ (0.01)	$ 0.01	$ 0.00	$ (0.02)	$ 0.02	$ (0.01)	$ 0.08