Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Net Income Per Common Share (Textual) [Abstract]
Total weighted average restricted shares and antidilutive stock options (in shares)	7.0	7.7	7.3	7.9
Computation of basic and diluted net income attributable to Trinity Industries, Inc
Net income attributable to Trinity Industries, Inc.	$ 212.0	$ 164.2	$ 392.2	$ 390.6
Unvested restricted share participation	(6.5)	(5.5)	(12.2)	(13.3)
Net income attributable to Trinity Industries, Inc. – basic	$ 205.5	$ 158.7	$ 380.0	$ 377.3
Net income from continuing operations attributable to Trinity Industries, Inc. - basic, Average Shares	150.7	151.0	151.0	150.5
Net income attributable to Trinity Industries, Inc. - basic, EPS	$ 1.36	$ 1.05	$ 2.52	$ 2.51
Effect of dilutive securities:
Stock options, Income (Loss)	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Stock options, Average Shares	0.0	0.1	0.0	0.1
Convertible Subordinated Notes, Income (Loss)	$ 0.1	$ 0.2	$ 0.2	$ 0.4
Convertible Subordinated Notes, Average Shares	3.5	6.3	3.3	5.0
Net income attributable to Trinity Industries, Inc. – diluted	$ 205.6	$ 158.9	$ 380.2	$ 377.7
Net income from continuing operations attributable to Trinity Industries, Inc. - diluted, Average Shares	154.2	157.4	154.3	155.6
Net income attributable to Trinity Industries, Inc. - diluted, EPS	$ 1.33	$ 1.01	$ 2.46	$ 2.43