Net Income Attributable to Trinity industries, Inc. Per Common Share (Details) (USD $) In Millions, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Computation of basic and diluted net income attributable to Trinity Industries, Inc
Net income attributable to Trinity Industries, Inc.	$ 31.9	$ 29.7	$ 86.1	$ 50.1
Unvested restricted share participation	(1.0)	(1.0)	(2.9)	(1.7)
Net income attributable to Trinity Industries, Inc. - basic	30.9	28.7	83.2	48.4
Net income attributable to Trinity Industries, Inc. - basic, Average Shares	77.7	77.0	77.4	76.8
Net income attributable to Trinity Industries, Inc. - basic, EPS	$ 0.40	$ 0.37	$ 1.07	$ 0.63
Effect of dilutive securities:
Stock options	0.2	0.1	0.3	0.1
Net income attributable to Trinity Industries, Inc - diluted	$ 30.9	$ 28.7	$ 83.2	$ 48.4
Net income attributable to Trinity Industries, Inc. - diluted, Average Shares	77.9	77.1	77.7	76.9
Net income attributable to Trinity Industries, Inc. - diluted, EPS	$ 0.40	$ 0.37	$ 1.07	$ 0.63
Net Income Per Common Share (Textual) [Abstract]
Total weighted average restricted shares and antidilutive stock options	2.9	2.8	2.9	2.8