Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ 54.1	$ 103.4	$ 161.5
Revenues [Abstract]
Total revenues	2,509.1	2,397.4	3,089.8
Cost of revenues:
Total cost of revenues	1,938.8	1,775.2	2,312.0
Selling, engineering, and administrative expenses:
Total selling, engineering, and administrative expenses	296.6	339.3	313.9
Gains (losses) on disposition of property:
Net gains on railcar lease fleet sales owned more than one year at the time of sale	50.4	83.5	13.5
Other	(9.0)	1.9	1.5
Total gains on disposition of property	41.4	85.4	15.0
Total operating profit	315.1	368.3	478.9
Other (income) expense:
Interest income	(11.9)	(10.4)	(5.3)
Interest expense	179.3	184.0	181.9
Other, net	(3.9)	(0.7)	(7.7)
Total other (income) expense	163.5	172.9	168.9
Income (loss) before income taxes	151.6	195.4	310.0
Provision (benefit) for income taxes:
Current	(15.3)	(57.7)	(194.7)
Deferred	57.9	(357.1)	301.5
Total provision for income taxes	42.6	(414.8)	106.8
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	109.0	610.2	203.2
Discontinued operations:
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	54.1	103.4	161.5
Net income	163.1	713.6	364.7
Net income attributable to noncontrolling interest	3.8	11.1	21.1
Net income attributable to Trinity Industries, Inc.	$ 159.3	$ 702.5	$ 343.6
Basic earnings per common share:
Continuing operations (in dollars per share)	$ 0.72	$ 3.94	$ 1.19
Discontinued operations (in dollars per share)	0.37	0.68	1.06
Basic (in dollars per share)	1.09	4.62	2.25
Diluted earnings per common share:
Continuing operations (in dollars per share)	0.70	3.85	1.19
Discontinued operations (in dollars per share)	0.37	0.67	1.06
Diluted (in dollars per share)	$ 1.07	$ 4.52	$ 2.25
Weighted average number of shares outstanding:
Basic (in shares)	144.0	148.6	148.4
Diluted (in shares)	146.4	152.0	148.6
Dividends declared per common share (in dollars per share)	$ 0.52	$ 0.5	$ 0.44
Manufacturing
Revenues [Abstract]
Total revenues	$ 1,667.1	$ 1,555.2	$ 2,264.9
Cost of revenues:
Total cost of revenues	1,459.8	1,342.8	1,875.5
Selling, engineering, and administrative expenses:
Total selling, engineering, and administrative expenses	96.4	113.6	115.4
Leasing
Revenues [Abstract]
Total revenues	842.0	842.2	824.9
Cost of revenues:
Total cost of revenues	479.0	432.4	436.5
Selling, engineering, and administrative expenses:
Total selling, engineering, and administrative expenses	51.1	50.7	45.4
Other
Selling, engineering, and administrative expenses:
Total selling, engineering, and administrative expenses	$ 149.1	$ 175.0	$ 153.1