Note 16. Selected Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2024		Sep. 30, 2024		Jun. 30, 2024		Mar. 31, 2024		Dec. 31, 2023		Sep. 30, 2023		Jun. 30, 2023		Mar. 31, 2023		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues	$ 629.4		$ 798.8		$ 841.4		$ 809.6		$ 797.9		$ 821.3		$ 722.4		$ 641.7		$ 3,079.2	$ 2,983.3	$ 1,977.3
Cost of revenues:	474.4		629.3		662.4		644.9		637.0		679.5		601.2		538.5		2,411.0	2,456.2	1,609.6
Selling, engineering, and administrative expenses:	61.6		60.5		61.3		52.3		48.6		49.1		54.3		49.9		235.7	201.9	185.4
Gains on dispositions of property:	22.9		13.4		24.2		2.8		36.4		7.5		30.4		15.3		63.3	89.6	152.7
Restructuring activities, net	4.3		0.0		0.0		0.0		0.0		0.0		(1.8)		(0.4)		4.3	(2.2)	1.0
Total operating profit	112.0		122.4		141.9		115.2		148.7		100.2		99.1		69.0		491.5	417.0	334.0
Other (income) expense	64.5		66.0		66.7		72.5		68.2		67.9		68.2		63.7		269.7	268.0	207.5
Income from continuing operations before income taxes	47.5		56.4		75.2		42.7		80.5		32.3		30.9		5.3		221.8	149.0	126.5
Provision (benefit) for income taxes:	6.7		15.6		17.1		11.0		7.1		6.0		7.4		(11.5)		50.4	9.0	27.6
Income from continuing operations	40.8		40.8		58.1		31.7		73.4		26.3		23.5		16.8		171.4	140.0	98.9
Loss from discontinued operations, net of benefit for income taxes of $4.1, $3.6, and $1.1	(3.0)		(5.3)		(1.7)		(4.3)		(5.3)		(2.7)		(2.3)		(3.1)		(14.3)	(13.4)	(20.3)
Net income	37.8		35.5		56.4		27.4		68.1		23.6		21.2		13.7		157.1	126.6	72.9
Net income attributable to noncontrolling interest	8.9		4.1		2.0		3.7		5.3		1.8		4.2		9.3		18.7	20.6	12.8
Net income attributable to Trinity Industries, Inc.	$ 28.9		$ 31.4		$ 54.4		$ 23.7		$ 62.8		$ 21.8		$ 17.0		$ 4.4		$ 138.4	$ 106.0	$ 60.1
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.39	[1]	$ 0.45	[1]	$ 0.68	[1]	$ 0.34	[1]	$ 0.83	[1]	$ 0.30	[1]	$ 0.24	[1]	$ 0.09	[1]	$ 1.86	$ 1.47	$ 1.05
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	(0.04)	[1]	(0.07)	[1]	(0.02)	[1]	(0.05)	[1]	(0.06)	[1]	(0.03)	[1]	(0.03)	[1]	(0.04)	[1]	(0.17)	(0.16)	(0.32)
Earnings Per Share, Basic	0.35	[1]	0.38	[1]	0.66	[1]	0.29	[1]	0.77	[1]	0.27	[1]	0.21	[1]	0.05	[1]	1.69	1.31	0.73
Income (Loss) from Continuing Operations, Per Diluted Share	0.38	[1]	0.44	[1]	0.67	[1]	0.33	[1]	0.81	[1]	0.29	[1]	0.23	[1]	0.09	[1]	1.81	1.43	1.02
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	(0.04)	[1]	(0.07)	[1]	(0.02)	[1]	(0.05)	[1]	(0.06)	[1]	(0.03)	[1]	(0.03)	[1]	(0.04)	[1]	(0.17)	(0.16)	(0.31)
Earnings Per Share, Diluted	$ 0.34	[1]	$ 0.37	[1]	$ 0.65	[1]	$ 0.28	[1]	$ 0.75	[1]	$ 0.26	[1]	$ 0.20	[1]	$ 0.05	[1]	$ 1.64	$ 1.27	$ 0.71
Manufacturing [Member]
Revenues	$ 342.6		$ 509.6		$ 560.9		$ 525.3		$ 520.3		$ 560.0		$ 454.6		$ 409.0		$ 1,938.4	$ 1,943.9	$ 1,127.3
Cost of revenues:	305.4		460.7		505.8		476.3		478.5		523.0		434.1		391.9		1,748.2	1,827.5	1,083.3
Selling, engineering, and administrative expenses:																	32.8	30.5	29.1
Railcar Leasing and Services Group [Member]
Revenues	286.8		289.2		280.5		284.3		277.6		261.3		267.8		232.7		1,140.8	1,039.4	850.0
Cost of revenues:	$ 169.0		$ 168.6		$ 156.6		$ 168.6		$ 158.5		$ 156.5		$ 167.1		$ 146.6		662.8	628.7	526.3
Selling, engineering, and administrative expenses:																	$ 77.0	$ 62.0	$ 59.1

[1] The sum of the quarters may not necessarily be equal to the full year net income per common share amount.