Financial Statements for Guarantors of the Senior Notes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Condensed Income Statements, Captions [Line Items]
Revenues	$ 905.5	$ 1,184.9	$ 1,782.8	$ 2,372.8
Cost of revenues	681.9	897.7	1,341.6	1,787.6
Selling, engineering, and administrative expenses	112.8	106.7	215.1	203.2
Gains/(losses) on dispositions of property	24.4	11.1	25.7	13.0
Cost of revenues and operating costs	770.3	993.3	1,531.0	1,977.8
Total operating profit	135.2	191.6	251.8	395.0
Other (income) expense	43.9	39.4	88.0	83.3
Equity in earnings of subsidiaries, net of taxes	0.0	0.0	0.0	0.0
Income before income taxes	91.3	152.2	163.8	311.7
Provision (benefit) for income taxes	37.3	53.4	58.1	110.8
Net income	54.0	98.8	105.7	200.9
Net income attributable to noncontrolling interest	2.9	4.2	8.6	9.1
Net income attributable to Trinity Industries, Inc.	51.1	94.6	97.1	191.8
Other comprehensive income (loss)	2.2	2.0	4.3	4.9
Comprehensive income	56.2	100.8	110.0	205.8
Comprehensive income attributable to noncontrolling interest	3.6	4.9	10.1	10.3
Comprehensive income attributable to Trinity Industries, Inc.	52.6	95.9	99.9	195.5
Reportable legal entities | Parent
Condensed Income Statements, Captions [Line Items]
Revenues	0.0	0.0	0.0	0.0
Cost of revenues	1.4	(1.3)	3.8	(3.6)
Selling, engineering, and administrative expenses	35.9	33.2	68.7	56.8
Gains/(losses) on dispositions of property	0.1	(0.7)	0.6	(0.9)
Cost of revenues and operating costs	37.2	32.6	71.9	54.1
Total operating profit	(37.2)	(32.6)	(71.9)	(54.1)
Other (income) expense	5.1	(1.2)	11.4	(0.1)
Equity in earnings of subsidiaries, net of taxes	103.1	105.9	162.3	227.8
Income before income taxes	60.8	74.5	79.0	173.8
Provision (benefit) for income taxes	9.7	(20.1)	(18.1)	(18.0)
Net income	51.1	94.6	97.1	191.8
Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Trinity Industries, Inc.	51.1	94.6	97.1	191.8
Other comprehensive income (loss)	1.2	0.9	2.2	3.0
Comprehensive income	52.3	95.5	99.3	194.8
Comprehensive income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	52.3	95.5	99.3	194.8
Reportable legal entities | Combined Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	564.7	838.0	1,116.2	1,714.0
Cost of revenues	455.6	668.9	899.0	1,375.3
Selling, engineering, and administrative expenses	33.9	35.6	64.7	69.9
Gains/(losses) on dispositions of property	20.9	10.5	21.0	10.3
Cost of revenues and operating costs	468.6	694.0	942.7	1,434.9
Total operating profit	96.1	144.0	173.5	279.1
Other (income) expense	8.8	9.3	15.7	18.3
Equity in earnings of subsidiaries, net of taxes	26.1	16.0	43.2	42.6
Income before income taxes	113.4	150.7	201.0	303.4
Provision (benefit) for income taxes	31.5	60.1	70.5	105.0
Net income	81.9	90.6	130.5	198.4
Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Trinity Industries, Inc.	81.9	90.6	130.5	198.4
Other comprehensive income (loss)	0.0	0.0	0.0	0.0
Comprehensive income	81.9	90.6	130.5	198.4
Comprehensive income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	81.9	90.6	130.5	198.4
Reportable legal entities | Combined Non-Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	473.4	539.6	937.2	1,067.4
Cost of revenues	364.4	427.5	721.0	834.1
Selling, engineering, and administrative expenses	43.0	37.9	81.7	76.5
Gains/(losses) on dispositions of property	3.4	1.3	4.1	3.6
Cost of revenues and operating costs	404.0	464.1	798.6	907.0
Total operating profit	69.4	75.5	138.6	160.4
Other (income) expense	30.0	31.3	60.9	65.1
Equity in earnings of subsidiaries, net of taxes	0.0	0.0	0.0	0.0
Income before income taxes	39.4	44.2	77.7	95.3
Provision (benefit) for income taxes	9.8	11.7	19.5	20.4
Net income	29.6	32.5	58.2	74.9
Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Trinity Industries, Inc.	29.6	32.5	58.2	74.9
Other comprehensive income (loss)	1.0	1.1	2.1	1.9
Comprehensive income	30.6	33.6	60.3	76.8
Comprehensive income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	30.6	33.6	60.3	76.8
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenues	(132.6)	(192.7)	(270.6)	(408.6)
Cost of revenues	(139.5)	(197.4)	(282.2)	(418.2)
Selling, engineering, and administrative expenses	0.0	0.0	0.0	0.0
Gains/(losses) on dispositions of property	0.0	0.0	0.0	0.0
Cost of revenues and operating costs	(139.5)	(197.4)	(282.2)	(418.2)
Total operating profit	6.9	4.7	11.6	9.6
Other (income) expense	0.0	0.0	0.0	0.0
Equity in earnings of subsidiaries, net of taxes	(129.2)	(121.9)	(205.5)	(270.4)
Income before income taxes	(122.3)	(117.2)	(193.9)	(260.8)
Provision (benefit) for income taxes	(13.7)	1.7	(13.8)	3.4
Net income	(108.6)	(118.9)	(180.1)	(264.2)
Net income attributable to noncontrolling interest	2.9	4.2	8.6	9.1
Net income attributable to Trinity Industries, Inc.	(111.5)	(123.1)	(188.7)	(273.3)
Other comprehensive income (loss)	0.0	0.0	0.0	0.0
Comprehensive income	(108.6)	(118.9)	(180.1)	(264.2)
Comprehensive income attributable to noncontrolling interest	3.6	4.9	10.1	10.3
Comprehensive income attributable to Trinity Industries, Inc.	$ (112.2)	$ (123.8)	$ (190.2)	$ (274.5)