Financial Statements for Guarantors of the Senior Notes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Condensed Income Statements, Captions [Line Items]
Revenues	$ 1,111.7	$ 1,542.2	$ 3,484.5	$ 4,845.7
Cost of revenues	827.3	1,109.4	2,614.9	3,540.1
Selling, engineering, and administrative expenses	102.3	126.6	305.5	339.3
Gains/(losses) on dispositions of property	1.5	58.7	14.5	114.6
Cost of revenues and operating costs	928.1	1,177.3	2,905.9	3,764.8
Total operating profit	183.6	364.9	578.6	1,080.9
Other (income) expense	44.1	45.1	127.4	143.2
Equity in earnings of subsidiaries, net of taxes	0.0	0.0	0.0	0.0
Income before income taxes	139.5	319.8	451.2	937.7
Provision (benefit) for income taxes	49.9	107.6	160.7	315.7
Net income	89.6	212.2	290.5	622.0
Net income attributable to noncontrolling interest	5.4	7.9	14.5	25.5
Net income attributable to Trinity Industries, Inc.	84.2	204.3	276.0	596.5
Other comprehensive income (loss)	1.6	(1.1)	6.5	4.0
Comprehensive income	91.2	211.1	297.0	626.0
Comprehensive income attributable to noncontrolling interest	6.2	8.4	16.5	27.5
Comprehensive income attributable to Trinity Industries, Inc.	85.0	202.7	280.5	598.5
Reportable legal entities | Parent
Condensed Income Statements, Captions [Line Items]
Revenues	0.0	0.0	0.0	0.0
Cost of revenues	0.3	0.1	(3.3)	(1.8)
Selling, engineering, and administrative expenses	33.8	38.5	90.7	94.5
Gains/(losses) on dispositions of property	0.2	0.2	(0.7)	1.7
Cost of revenues and operating costs	33.9	38.4	88.1	91.0
Total operating profit	(33.9)	(38.4)	(88.1)	(91.0)
Other (income) expense	0.0	4.8	(0.1)	11.9
Equity in earnings of subsidiaries, net of taxes	114.8	283.3	343.2	726.4
Income before income taxes	80.9	240.1	255.2	623.5
Provision (benefit) for income taxes	(3.3)	35.8	(20.8)	27.0
Net income	84.2	204.3	276.0	596.5
Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Trinity Industries, Inc.	84.2	204.3	276.0	596.5
Other comprehensive income (loss)	0.3	(1.0)	3.3	(0.1)
Comprehensive income	84.5	203.3	279.3	596.4
Comprehensive income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	84.5	203.3	279.3	596.4
Reportable legal entities | Combined Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	686.7	1,084.3	2,186.8	3,484.2
Cost of revenues	555.2	818.6	1,772.3	2,708.0
Selling, engineering, and administrative expenses	27.2	41.2	92.3	112.4
Gains/(losses) on dispositions of property	0.2	31.0	10.6	38.9
Cost of revenues and operating costs	582.2	828.8	1,854.0	2,781.5
Total operating profit	104.5	255.5	332.8	702.7
Other (income) expense	9.9	7.8	27.2	23.8
Equity in earnings of subsidiaries, net of taxes	33.9	56.9	76.5	181.5
Income before income taxes	128.5	304.6	382.1	860.4
Provision (benefit) for income taxes	30.9	96.5	116.6	276.5
Net income	97.6	208.1	265.5	583.9
Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Trinity Industries, Inc.	97.6	208.1	265.5	583.9
Other comprehensive income (loss)	(0.1)	0.0	(0.1)	(0.5)
Comprehensive income	97.5	208.1	265.4	583.4
Comprehensive income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	97.5	208.1	265.4	583.4
Reportable legal entities | Combined Non-Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	620.0	678.3	1,881.4	2,049.6
Cost of revenues	474.0	513.2	1,446.2	1,534.4
Selling, engineering, and administrative expenses	41.3	46.9	122.5	132.4
Gains/(losses) on dispositions of property	1.1	27.5	4.6	74.0
Cost of revenues and operating costs	514.2	532.6	1,564.1	1,592.8
Total operating profit	105.8	145.7	317.3	456.8
Other (income) expense	34.2	32.5	100.3	107.5
Equity in earnings of subsidiaries, net of taxes	0.0	0.0	0.0	0.0
Income before income taxes	71.6	113.2	217.0	349.3
Provision (benefit) for income taxes	19.7	21.1	58.9	54.3
Net income	51.9	92.1	158.1	295.0
Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Trinity Industries, Inc.	51.9	92.1	158.1	295.0
Other comprehensive income (loss)	1.4	(0.1)	3.3	4.6
Comprehensive income	53.3	92.0	161.4	299.6
Comprehensive income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	53.3	92.0	161.4	299.6
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenues	(195.0)	(220.4)	(583.7)	(688.1)
Cost of revenues	(202.2)	(222.5)	(600.3)	(700.5)
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	(202.2)	(222.5)	(600.3)	(700.5)
Total operating profit	7.2	2.1	16.6	12.4
Other (income) expense	0.0	0.0	0.0	0.0
Equity in earnings of subsidiaries, net of taxes	(148.7)	(340.2)	(419.7)	(907.9)
Income before income taxes	(141.5)	(338.1)	(403.1)	(895.5)
Provision (benefit) for income taxes	2.6	(45.8)	6.0	(42.1)
Net income	(144.1)	(292.3)	(409.1)	(853.4)
Net income attributable to noncontrolling interest	5.4	7.9	14.5	25.5
Net income attributable to Trinity Industries, Inc.	(149.5)	(300.2)	(423.6)	(878.9)
Other comprehensive income (loss)	0.0	0.0	0.0	0.0
Comprehensive income	(144.1)	(292.3)	(409.1)	(853.4)
Comprehensive income attributable to noncontrolling interest	6.2	8.4	16.5	27.5
Comprehensive income attributable to Trinity Industries, Inc.	$ (150.3)	$ (300.7)	$ (425.6)	$ (880.9)