Financial Statements for Guarantors of the Senior Notes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Condensed Income Statements, Captions [Line Items]
Revenues	$ 1,542.2	$ 1,562.8	$ 4,845.7	$ 4,508.6
Cost of revenues	1,109.4	1,172.2	3,540.1	3,344.5
Selling, engineering, and administrative expenses	126.6	113.0	339.3	293.0
Gains on dispositions of property	58.7	3.6	114.6	103.4
Cost of revenues and operating costs	1,177.3	1,281.6	3,764.8	3,534.1
Total operating profit	364.9	281.2	1,080.9	974.5
Other (income) expense	45.1	46.2	143.2	137.0
Equity in earnings of subsidiaries, net of taxes	0.0	0.0	0.0	0.0
Income before income taxes	319.8	235.0	937.7	837.5
Provision (benefit) for income taxes	107.6	78.1	315.7	274.5
Net income	212.2	156.9	622.0	563.0
Net income attributable to noncontrolling interest	7.9	7.5	25.5	23.0
Net income attributable to Trinity Industries, Inc.	204.3	149.4	596.5	540.0
Other comprehensive income (loss)	(1.1)	4.4	4.0	11.5
Comprehensive income	211.1	161.3	626.0	574.5
Comprehensive income attributable to noncontrolling interest	8.4	8.6	27.5	25.4
Comprehensive income attributable to Trinity Industries, Inc.	202.7	152.7	598.5	549.1
Reportable legal entities | Parent
Condensed Income Statements, Captions [Line Items]
Revenues	0.0	0.0	0.0	0.0
Cost of revenues	0.1	0.4	(1.8)	0.4
Selling, engineering, and administrative expenses	38.5	37.4	94.5	87.5
Gains on dispositions of property	0.2	0.1	1.7	(0.1)
Cost of revenues and operating costs	38.4	37.7	91.0	88.0
Total operating profit	(38.4)	(37.7)	(91.0)	(88.0)
Other (income) expense	4.8	5.5	11.9	13.7
Equity in earnings of subsidiaries, net of taxes	283.3	211.1	726.4	616.5
Income before income taxes	240.1	167.9	623.5	514.8
Provision (benefit) for income taxes	35.8	18.5	27.0	(25.2)
Net income	204.3	149.4	596.5	540.0
Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Trinity Industries, Inc.	204.3	149.4	596.5	540.0
Other comprehensive income (loss)	(1.0)	0.8	(0.1)	2.1
Comprehensive income	203.3	150.2	596.4	542.1
Comprehensive income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	203.3	150.2	596.4	542.1
Reportable legal entities | Combined Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	1,084.3	1,048.2	3,484.2	3,055.9
Cost of revenues	818.6	823.9	2,708.0	2,346.1
Selling, engineering, and administrative expenses	41.2	33.5	112.4	84.2
Gains on dispositions of property	31.0	0.1	38.9	41.3
Cost of revenues and operating costs	828.8	857.3	2,781.5	2,389.0
Total operating profit	255.5	190.9	702.7	666.9
Other (income) expense	7.8	2.7	23.8	10.3
Equity in earnings of subsidiaries, net of taxes	56.9	28.1	181.5	104.5
Income before income taxes	304.6	216.3	860.4	761.1
Provision (benefit) for income taxes	96.5	43.0	276.5	255.3
Net income	208.1	173.3	583.9	505.8
Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Trinity Industries, Inc.	208.1	173.3	583.9	505.8
Other comprehensive income (loss)	0.0	0.0	(0.5)	0.0
Comprehensive income	208.1	173.3	583.4	505.8
Comprehensive income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	208.1	173.3	583.4	505.8
Reportable legal entities | Combined Non-Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	678.3	716.3	2,049.6	2,019.5
Cost of revenues	513.2	549.8	1,534.4	1,565.3
Selling, engineering, and administrative expenses	46.9	42.1	132.4	121.3
Gains on dispositions of property	27.5	3.4	74.0	62.2
Cost of revenues and operating costs	532.6	588.5	1,592.8	1,624.4
Total operating profit	145.7	127.8	456.8	395.1
Other (income) expense	32.5	38.0	107.5	113.0
Equity in earnings of subsidiaries, net of taxes	0.0	0.0	0.0	0.0
Income before income taxes	113.2	89.8	349.3	282.1
Provision (benefit) for income taxes	21.1	21.3	54.3	57.4
Net income	92.1	68.5	295.0	224.7
Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Trinity Industries, Inc.	92.1	68.5	295.0	224.7
Other comprehensive income (loss)	(0.1)	3.6	4.6	9.4
Comprehensive income	92.0	72.1	299.6	234.1
Comprehensive income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	92.0	72.1	299.6	234.1
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenues	(220.4)	(201.7)	(688.1)	(566.8)
Cost of revenues	(222.5)	(201.9)	(700.5)	(567.3)
Selling, engineering, and administrative expenses	0.0	0.0	0.0	0.0
Gains on dispositions of property	0.0	0.0	0.0	0.0
Cost of revenues and operating costs	(222.5)	(201.9)	(700.5)	(567.3)
Total operating profit	2.1	0.2	12.4	0.5
Other (income) expense	0.0	0.0	0.0	0.0
Equity in earnings of subsidiaries, net of taxes	(340.2)	(239.2)	(907.9)	(721.0)
Income before income taxes	(338.1)	(239.0)	(895.5)	(720.5)
Provision (benefit) for income taxes	(45.8)	(4.7)	(42.1)	(13.0)
Net income	(292.3)	(234.3)	(853.4)	(707.5)
Net income attributable to noncontrolling interest	7.9	7.5	25.5	23.0
Net income attributable to Trinity Industries, Inc.	(300.2)	(241.8)	(878.9)	(730.5)
Other comprehensive income (loss)	0.0	0.0	0.0	0.0
Comprehensive income	(292.3)	(234.3)	(853.4)	(707.5)
Comprehensive income attributable to noncontrolling interest	8.4	8.6	27.5	25.4
Comprehensive income attributable to Trinity Industries, Inc.	$ (300.7)	$ (242.9)	$ (880.9)	$ (732.9)