Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Total weighted average restricted shares and antidilutive stock options									6.6	6.8	7.4
Earnings Per Share Reconciliation [Abstract]
Net income	$ 74.2	$ 89.6	$ 98.8	$ 102.1	$ 204.0	$ 212.2	$ 220.8	$ 189.0	$ 364.7	$ 826.0	$ 709.3
Net income attributable to noncontrolling interest									21.1	29.5	31.1
Net income attributable to Trinity Industries, Inc.	$ 67.6	$ 84.2	$ 94.6	$ 97.2	$ 200.0	$ 204.3	$ 212.0	$ 180.2	343.6	796.5	678.2
Unvested restricted share participation									9.4	24.1	22.1
Net income attributable to Trinity Industries, Inc. – basic									$ 334.2	$ 772.4	$ 656.1
Net income attributable to Trinity Industries, Inc. - basic (shares)									148.4	150.2	151.0
Net income attributable to Trinity Industries, Inc. - basic (EPS)	$ 0.44	$ 0.55	$ 0.62	$ 0.64	$ 1.30	$ 1.32	$ 1.36	$ 1.15	$ 2.25	$ 5.14	$ 4.35
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Stock options									$ 0.0	$ 0.0	$ 0.0
Stock options (shares)									0.0	0.0	0.1
Convertible subordinated notes									$ 0.0	$ 0.3	$ 0.7
Convertible subordinated notes (shares)									0.2	2.0	5.6
Net income attributable to Trinity Industries, Inc. – diluted									$ 334.2	$ 772.7	$ 656.8
Net income attributable to Trinity Industries, Inc - diluted (shares)									148.6	152.2	156.7
Net income attributable to Trinity Industries, Inc. - diluted (EPS)	$ 0.44	$ 0.55	$ 0.62	$ 0.64	$ 1.30	$ 1.31	$ 1.33	$ 1.13	$ 2.25	$ 5.08	$ 4.19