Earnings Per Common Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Computation of basic and diluted net income attributable to Trinity Industries, Inc
Net income attributable to Trinity Industries, Inc.	$ 67.8	$ 30.0	$ 120.7	$ 54.2
Unvested restricted share participation	(2.3)	(1.0)	(4.0)	(1.9)
Net income attributable to Trinity Industries, Inc. - basic	65.5	29.0	116.7	52.3
Net income attributable to Trinity Industries, Inc. - basic, Average Shares	77.7	77.4	77.7	77.2
Net income attributable to Trinity Industries, Inc. - basic, EPS	$ 0.84	$ 0.37	$ 1.50	$ 0.68
Effect of dilutive securities:
Stock option ( in shares)	0.2	0.3	0.2	0.3
Net income attributable to Trinity Industries, Inc - diluted	$ 65.5	$ 29.0	$ 116.7	$ 52.3
Net income attributable to Trinity Industries, Inc. - diluted, Average Shares	77.9	77.7	77.9	77.5
Net income attributable to Trinity Industries, Inc. - diluted, EPS	$ 0.84	$ 0.37	$ 1.50	$ 0.67
Net Income Per Common Share (Textual) [Abstract]
Total weighted average restricted shares and antidilutive stock options (in shares)	3.3	3.0	3.2	3.0