Consolidated Statements of Operations (unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues [Abstract]
Revenues	$ 509.2	$ 736.0	$ 1,124.4	$ 1,340.8
Cost of revenues:
Cost of Goods and Services Sold	396.6	578.5	878.6	1,041.9
Selling, engineering, and administrative expenses:
Selling, General and Administrative Expense	56.8	69.8	121.1	129.4
Gains on dispositions of property:
Net gains on railcar lease fleet sales owned more than one year at the time of sale	5.7	18.7	14.4	26.6
Other	0.9	0.6	1.8	2.7
Gain (Loss) on Disposition of Property Plant Equipment	6.6	19.3	16.2	29.3
Asset Impairment Charges	369.4	0.0	369.4	0.0
Restructuring Charges	0.3	0.0	5.8	0.0
Total operating profit (loss)	(307.3)	107.0	(234.3)	198.8
Other (income) expense:
Interest income	0.0	(1.6)	(2.4)	(2.9)
Interest expense	53.0	57.0	114.3	109.7
Other Nonoperating Income (Expense)	(0.7)	(0.1)	(1.5)	0.2
Other Nonoperating Expense	52.3	55.3	110.4	107.0
Income (loss) from continuing operations before income taxes	(359.6)	51.7	(344.7)	91.8
Current Income Tax Expense (Benefit)	(79.7)	1.0	(452.5)	0.2
Provision for deferred income taxes	7.9	13.1	233.1	22.8
Income Tax Expense (Benefit)	(71.8)	14.1	(219.4)	23.0
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(287.8)	37.6	(125.3)	68.8
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	0.0	(0.8)	(0.2)	(1.9)
Discontinued Operation, Tax Effect of Discontinued Operation	0.0	(0.3)	(0.1)	(0.5)
Net income (loss)	(287.8)	36.8	(125.5)	66.9
Net income (loss) attributable to noncontrolling interest	(80.9)	0.4	(80.3)	(0.1)
Net income (loss) attributable to Trinity Industries, Inc.	$ (206.9)	$ 36.4	$ (45.2)	$ 67.0
Basic earnings per common share:
Income (Loss) from Continuing Operations, Per Basic Share	$ (1.76)	$ 0.29	$ (0.38)	$ 0.53
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0	(0.01)	0	(0.02)
Earnings Per Share, Basic	(1.76)	0.28	(0.38)	0.51
Income (Loss) from Continuing Operations, Per Diluted Share	(1.76)	0.29	(0.38)	0.52
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	0	(0.01)	0	(0.01)
Earnings Per Share, Diluted	$ (1.76)	$ 0.28	$ (0.38)	$ 0.51
Weighted average number of shares outstanding:
Weighted Average Number of Shares Outstanding, Basic	117.3	127.6	117.6	129.0
Weighted Average Number of Shares Outstanding, Diluted	117.3	129.2	117.6	130.7
Manufacturing
Revenues [Abstract]
Revenues	$ 316.6	$ 459.1	$ 695.7	$ 863.7
Cost of revenues:
Cost of Goods and Services Sold	293.7	399.6	637.1	751.2
Selling, engineering, and administrative expenses:
Selling, General and Administrative Expense	19.6	26.5	41.5	49.7
Leasing
Revenues [Abstract]
Revenues	192.6	276.9	428.7	477.1
Cost of revenues:
Cost of Goods and Services Sold	102.9	178.9	241.5	290.7
Selling, engineering, and administrative expenses:
Selling, General and Administrative Expense	13.0	12.7	27.3	25.5
Other
Selling, engineering, and administrative expenses:
Selling, General and Administrative Expense	$ 24.2	$ 30.6	$ 52.3	$ 54.2