Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Total weighted average restricted shares and antidilutive stock options (in shares)	6.3	6.3	6.7	6.9
Computation of basic and diluted net income attributable to Trinity Industries, Inc
Net income attributable to Trinity Industries, Inc.	$ 84.2	$ 204.3	$ 276.0	$ 596.5
Unvested restricted share participation	(2.2)	(6.0)	(7.7)	(18.2)
Net income attributable to Trinity Industries, Inc. – basic	$ 82.0	$ 198.3	$ 268.3	$ 578.3
Net income attributable to Trinity Industries, Inc. - basic, Average Shares (in shares)	148.7	150.0	148.3	150.6
Net income attributable to Trinity Industries, Inc. - basic, EPS (in dollars per share)	$ 0.55	$ 1.32	$ 1.81	$ 3.84
Effect of dilutive securities:
Convertible subordinated notes, Income (Loss)	$ 0.0	$ 0.0	$ 0.0	$ 0.3
Convertible subordinated notes, Average Shares	0.0	0.9	0.0	2.5
Net income attributable to Trinity Industries, Inc. – diluted	$ 82.0	$ 198.3	$ 268.3	$ 578.6
Net income attributable to Trinity Industries, Inc. - diluted, Average Shares	148.7	150.9	148.3	153.1
Net income attributable to Trinity Industries, Inc. - diluted, EPS (in dollars per share)	$ 0.55	$ 1.31	$ 1.81	$ 3.78