Financial Statements for Guarantors of the Senior Notes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Condensed Income Statements, Captions [Line Items]
Revenues	$ 877.3	$ 1,187.9
Cost of revenues	659.7	889.9
Selling, engineering, and administrative expenses	102.3	96.5
Gains/(losses) on dispositions of property	1.3	1.9
Cost of revenues and operating costs	760.7	984.5
Total operating profit	116.6	203.4
Other (income) expense	44.1	43.9
Equity in earnings of subsidiaries, net of taxes	0.0	0.0
Income before income taxes	72.5	159.5
Provision (benefit) for income taxes	20.8	57.4
Net income	51.7	102.1
Net income attributable to noncontrolling interest	5.7	4.9
Net income attributable to Trinity Industries, Inc.	46.0	97.2
Other comprehensive income (loss)	2.1	2.9
Comprehensive income	53.8	105.0
Comprehensive income attributable to noncontrolling interest	6.5	5.4
Comprehensive income attributable to Trinity Industries, Inc.	47.3	99.6
Reportable legal entities | Parent
Condensed Income Statements, Captions [Line Items]
Revenues	0.0	0.0
Cost of revenues	2.4	(2.2)
Selling, engineering, and administrative expenses	32.7	23.5
Gains/(losses) on dispositions of property	0.5	(0.3)
Cost of revenues and operating costs	34.6	21.6
Total operating profit	(34.6)	(21.6)
Other (income) expense	6.2	1.1
Equity in earnings of subsidiaries, net of taxes	57.6	122.0
Income before income taxes	16.8	99.3
Provision (benefit) for income taxes	(29.2)	2.1
Net income	46.0	97.2
Net income attributable to noncontrolling interest	0.0	0.0
Net income attributable to Trinity Industries, Inc.	46.0	97.2
Other comprehensive income (loss)	1.0	1.9
Comprehensive income	47.0	99.1
Comprehensive income attributable to noncontrolling interest	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	47.0	99.1
Reportable legal entities | Combined Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	550.6	876.0
Cost of revenues	441.9	706.4
Selling, engineering, and administrative expenses	30.8	34.3
Gains/(losses) on dispositions of property	0.1	(0.2)
Cost of revenues and operating costs	472.6	740.9
Total operating profit	78.0	135.1
Other (income) expense	6.9	9.0
Equity in earnings of subsidiaries, net of taxes	17.0	26.6
Income before income taxes	88.1	152.7
Provision (benefit) for income taxes	40.4	44.9
Net income	47.7	107.8
Net income attributable to noncontrolling interest	0.0	0.0
Net income attributable to Trinity Industries, Inc.	47.7	107.8
Other comprehensive income (loss)	0.0	0.0
Comprehensive income	47.7	107.8
Comprehensive income attributable to noncontrolling interest	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	47.7	107.8
Reportable legal entities | Combined Non-Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	464.0	527.9
Cost of revenues	356.7	406.6
Selling, engineering, and administrative expenses	38.8	38.7
Gains/(losses) on dispositions of property	0.7	2.4
Cost of revenues and operating costs	394.8	442.9
Total operating profit	69.2	85.0
Other (income) expense	31.0	33.8
Equity in earnings of subsidiaries, net of taxes	0.0	0.0
Income before income taxes	38.2	51.2
Provision (benefit) for income taxes	9.8	8.6
Net income	28.4	42.6
Net income attributable to noncontrolling interest	0.0	0.0
Net income attributable to Trinity Industries, Inc.	28.4	42.6
Other comprehensive income (loss)	1.1	1.0
Comprehensive income	29.5	43.6
Comprehensive income attributable to noncontrolling interest	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	29.5	43.6
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenues	(137.3)	(216.0)
Cost of revenues	(141.3)	(220.9)
Selling, engineering, and administrative expenses	0.0	0.0
Gains/(losses) on dispositions of property	0.0	0.0
Cost of revenues and operating costs	(141.3)	(220.9)
Total operating profit	4.0	4.9
Other (income) expense	0.0	0.0
Equity in earnings of subsidiaries, net of taxes	(74.6)	(148.6)
Income before income taxes	(70.6)	(143.7)
Provision (benefit) for income taxes	(0.2)	1.8
Net income	(70.4)	(145.5)
Net income attributable to noncontrolling interest	5.7	4.9
Net income attributable to Trinity Industries, Inc.	(76.1)	(150.4)
Other comprehensive income (loss)	0.0	0.0
Comprehensive income	(70.4)	(145.5)
Comprehensive income attributable to noncontrolling interest	6.5	5.4
Comprehensive income attributable to Trinity Industries, Inc.	$ (76.9)	$ (150.9)