Earnings Per Common Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Computation of basic and diluted net income attributable to Trinity Industries, Inc
Net income attributable to Trinity Industries, Inc.	$ 52.9	$ 24.2
Unvested restricted share participation	(1.7)	(0.9)
Net income attributable to Trinity Industries, Inc. - basic	51.2	23.3
Net income attributable to Trinity Industries, Inc. - basic, Average Shares	77.8	77.1
Net income attributable to Trinity Industries, Inc. - basic, EPS	$ 0.66	$ 0.30
Effect of dilutive securities:
Stock options	0.3	0.3
Net income attributable to Trinity Industries, Inc - diluted	$ 51.2	$ 23.3
Net income attributable to Trinity Industries, Inc. - diluted, Average Shares	78.1	77.4
Net income attributable to Trinity Industries, Inc. - diluted, EPS	$ 0.66	$ 0.30
Net Income Per Common Share (Textual) [Abstract]
Total weighted average restricted shares and antidilutive stock options	3.1	2.9