Earnings Per Common Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Computation of basic and diluted net income attributable to Trinity Industries, Inc
Net income attributable to Trinity Industries, Inc.	$ 63.2	$ 31.9	$ 183.9	$ 86.1
Unvested restricted share participation	(2.1)	(1.0)	(6.1)	(2.9)
Net income attributable to Trinity Industries, Inc. - basic	61.1	30.9	177.8	83.2
Net income attributable to Trinity Industries, Inc. - basic, Average Shares	76.5	77.7	77.3	77.4
Net income attributable to Trinity Industries, Inc. - basic, EPS	$ 0.80	$ 0.40	$ 2.30	$ 1.07
Effect of dilutive securities:
Stock options, Income (Loss)	0	0	0	0
Stock options, Average Shares	0.2	0.2	0.2	0.3
Net income attributable to Trinity Industries, Inc - diluted	$ 61.1	$ 30.9	$ 177.8	$ 83.2
Net income attributable to Trinity Industries, Inc. - diluted, Average Shares	76.7	77.9	77.5	77.7
Net income attributable to Trinity Industries, Inc. - diluted, EPS	$ 0.80	$ 0.40	$ 2.29	$ 1.07
Net Income Per Common Share (Textual) [Abstract]
Total weighted average restricted shares and antidilutive stock options, number of shares	3.3	2.9	3.2	2.9