Consolidated Statements of Operations (unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues [Abstract]
Revenues	$ 813.6	$ 606.9	$ 2,154.4	$ 1,774.1
Cost of revenues:
Total cost of revenues	649.1	466.5	1,691.0	1,348.3
Selling, engineering, and administrative expenses:
Selling, engineering, and administrative expenses	62.1	75.6	191.5	224.6
Gains (losses) on dispositions of property:
Net gains on railcar lease fleet sales owned more than one year at the time of sale	18.1	9.4	44.7	21.0
Other	(0.2)	1.0	2.5	3.1
Total gains (losses) on disposition of property	17.9	10.4	47.2	24.1
Total operating profit	120.3	75.2	319.1	225.3
Other (income) expense:
Interest income	(1.8)	(2.4)	(4.7)	(10.0)
Interest expense	55.8	42.8	165.5	132.9
Other Nonoperating Income (Expense)	0.0	(0.4)	0.2	(3.5)
Other Nonoperating Expense	54.0	40.0	161.0	119.4
Income from continuing operations before income taxes	66.3	35.2	158.1	105.9
Provision for income taxes	18.2	6.7	41.2	24.9
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	48.1	28.5	116.9	81.0
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(0.4)	(0.2)	(2.3)	54.4
Net income	47.7	28.3	114.6	135.4
Net income (loss) attributable to noncontrolling interest	(1.3)	0.6	(1.4)	3.4
Net income attributable to Trinity Industries, Inc.	$ 49.0	$ 27.7	$ 116.0	$ 132.0
Basic earnings per common share:
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.39	$ 0.19	$ 0.91	$ 0.52
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0	0	(0.02)	0.37
Basic (in dollars per share)	0.39	0.19	0.89	0.89
Income (Loss) from Continuing Operations, Per Diluted Share	0.39	0.19	0.90	0.51
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	0	0	(0.02)	0.36
Diluted (in dollars per share)	$ 0.39	$ 0.19	$ 0.88	$ 0.87
Weighted average number of shares outstanding:
Basic (in shares)	124.7	145.0	127.6	146.1
Diluted (in shares)	126.0	145.8	129.2	148.8
Manufacturing
Revenues [Abstract]
Revenues	$ 487.4	$ 379.7	$ 1,351.1	$ 1,159.4
Cost of revenues:
Total cost of revenues	430.7	333.5	1,181.9	1,003.4
Selling, engineering, and administrative expenses:
Selling, engineering, and administrative expenses	27.5	26.3	77.2	72.9
Leasing
Revenues [Abstract]
Revenues	326.2	227.2	803.3	614.7
Cost of revenues:
Total cost of revenues	218.4	133.0	509.1	344.9
Selling, engineering, and administrative expenses:
Selling, engineering, and administrative expenses	10.7	11.9	36.2	36.7
Other
Selling, engineering, and administrative expenses:
Selling, engineering, and administrative expenses	$ 23.9	$ 37.4	$ 78.1	$ 115.0