Financial Statements for Guarantors of the Senior Notes - Statement of Operations and Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Condensed Income Statements, Captions [Line Items]
Revenues	$ 973.6	$ 1,111.7	$ 2,756.4	$ 3,484.5
Cost of revenues	722.2	827.3	2,063.8	2,614.9
Selling, engineering, and administrative expenses	114.5	102.3	329.6	305.5
Gains/(losses) on dispositions of property	16.1	1.5	41.8	14.5
Cost of revenues and operating costs	820.6	928.1	2,351.6	2,905.9
Total operating profit	153.0	183.6	404.8	578.6
Other (income) expense	45.4	44.1	133.4	127.4
Equity in earnings of subsidiaries, net of taxes	0.0	0.0	0.0	0.0
Income before income taxes	107.6	139.5	271.4	451.2
Provision (benefit) for income taxes	39.7	49.9	97.8	160.7
Net income	67.9	89.6	173.6	290.5
Net income attributable to noncontrolling interest	1.0	5.4	9.6	14.5
Net income attributable to Trinity Industries, Inc.	66.9	84.2	164.0	276.0
Other comprehensive income (loss)	2.1	1.6	6.4	6.5
Comprehensive income	70.0	91.2	180.0	297.0
Comprehensive income attributable to noncontrolling interest	1.5	6.2	11.6	16.5
Comprehensive income attributable to Trinity Industries, Inc.	68.5	85.0	168.4	280.5
Reportable legal entities | Parent
Condensed Income Statements, Captions [Line Items]
Revenues	0.0	0.0	0.0	0.0
Cost of revenues	(0.1)	0.3	3.7	(3.3)
Selling, engineering, and administrative expenses	39.5	33.8	108.2	90.7
Gains/(losses) on dispositions of property	(0.1)	0.2	0.5	(0.7)
Cost of revenues and operating costs	39.5	33.9	111.4	88.1
Total operating profit	(39.5)	(33.9)	(111.4)	(88.1)
Other (income) expense	5.7	0.0	17.1	(0.1)
Equity in earnings of subsidiaries, net of taxes	111.7	114.8	274.1	342.7
Income before income taxes	66.5	80.9	145.6	254.7
Provision (benefit) for income taxes	(0.4)	(3.3)	(18.4)	(21.3)
Net income	66.9	84.2	164.0	276.0
Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Trinity Industries, Inc.	66.9	84.2	164.0	276.0
Other comprehensive income (loss)	1.8	0.3	4.1	3.3
Comprehensive income	68.7	84.5	168.1	279.3
Comprehensive income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	68.7	84.5	168.1	279.3
Reportable legal entities | Combined Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	622.5	770.0	1,738.6	2,484.0
Cost of revenues	493.3	615.6	1,392.3	1,990.8
Selling, engineering, and administrative expenses	35.6	29.8	100.3	99.7
Gains/(losses) on dispositions of property	15.9	0.2	36.9	10.6
Cost of revenues and operating costs	513.0	645.2	1,455.7	2,079.9
Total operating profit	109.5	124.8	282.9	404.1
Other (income) expense	6.4	10.4	22.1	28.8
Equity in earnings of subsidiaries, net of taxes	17.5	33.9	60.6	76.5
Income before income taxes	120.6	148.3	321.4	451.8
Provision (benefit) for income taxes	35.5	37.6	105.8	142.7
Net income	85.1	110.7	215.6	309.1
Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Trinity Industries, Inc.	85.1	110.7	215.6	309.1
Other comprehensive income (loss)	0.0	(0.1)	0.0	(0.1)
Comprehensive income	85.1	110.6	215.6	309.0
Comprehensive income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	85.1	110.6	215.6	309.0
Reportable legal entities | Combined Non-Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	501.3	542.3	1,438.5	1,609.7
Cost of revenues	385.5	419.2	1,106.4	1,253.3
Selling, engineering, and administrative expenses	39.4	38.7	121.1	115.1
Gains/(losses) on dispositions of property	0.3	1.1	4.4	4.6
Cost of revenues and operating costs	424.6	456.8	1,223.1	1,363.8
Total operating profit	76.7	85.5	215.4	245.9
Other (income) expense	33.3	33.7	94.2	98.7
Equity in earnings of subsidiaries, net of taxes	0.0	0.0	0.0	0.0
Income before income taxes	43.4	51.8	121.2	147.2
Provision (benefit) for income taxes	6.4	13.0	26.0	33.3
Net income	37.0	38.8	95.2	113.9
Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Trinity Industries, Inc.	37.0	38.8	95.2	113.9
Other comprehensive income (loss)	0.3	1.4	2.3	3.3
Comprehensive income	37.3	40.2	97.5	117.2
Comprehensive income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	37.3	40.2	97.5	117.2
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenues	(150.2)	(200.6)	(420.7)	(609.2)
Cost of revenues	(156.5)	(207.8)	(438.6)	(625.9)
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	(156.5)	(207.8)	(438.6)	(625.9)
Total operating profit	6.3	7.2	17.9	16.7
Other (income) expense	0.0	0.0	0.0	0.0
Equity in earnings of subsidiaries, net of taxes	(129.2)	(148.7)	(334.7)	(419.2)
Income before income taxes	(122.9)	(141.5)	(316.8)	(402.5)
Provision (benefit) for income taxes	(1.8)	2.6	(15.6)	6.0
Net income	(121.1)	(144.1)	(301.2)	(408.5)
Net income attributable to noncontrolling interest	1.0	5.4	9.6	14.5
Net income attributable to Trinity Industries, Inc.	(122.1)	(149.5)	(310.8)	(423.0)
Other comprehensive income (loss)	0.0	0.0	0.0	0.0
Comprehensive income	(121.1)	(144.1)	(301.2)	(408.5)
Comprehensive income attributable to noncontrolling interest	1.5	6.2	11.6	16.5
Comprehensive income attributable to Trinity Industries, Inc.	$ (122.6)	$ (150.3)	$ (312.8)	$ (425.0)