Financial Statements for Guarantors of the Senior Notes - Statement of Operations and Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Condensed Income Statements, Captions [Line Items]
Revenues	$ 615.2	$ 604.8
Cost of revenues	482.0	463.4
Selling, engineering, and administrative expenses	64.3	59.6
Gains on dispositions of property	9.6	10.0
Restructuring Charges	5.5	0.0
Cost of revenues and operating costs	542.2	513.0
Total operating profit	73.0	91.8
Other Nonoperating Expense	58.1	51.7
Equity in earnings of subsidiaries, net of taxes	0.0	0.0
Income before income taxes	14.9	40.1
Provision (benefit) for income taxes	(147.6)	8.9
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	162.5	31.2
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(0.2)	(1.1)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	162.3	30.1
Net Income (Loss) Attributable to Noncontrolling Interest	0.6	(0.5)
Net Income (Loss) Attributable to Parent	161.7	30.6
Other Comprehensive Income (Loss), Net of Tax	(23.2)	(3.8)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	139.1	26.3
Comprehensive income attributable to noncontrolling interest	0.9	(0.2)
Comprehensive income attributable to Trinity Industries, Inc.	138.2	26.5
Reportable legal entities | Parent
Condensed Income Statements, Captions [Line Items]
Revenues	0.0	0.0
Cost of revenues	1.5	0.9
Selling, engineering, and administrative expenses	24.1	20.7
Gains on dispositions of property	0.1	0.0
Restructuring Charges	6.4
Cost of revenues and operating costs	31.9	21.6
Total operating profit	(31.9)	(21.6)
Other (income) expense	0.4	4.7
Equity in earnings of subsidiaries, net of taxes	54.9	54.2
Income before income taxes	22.6	27.9
Provision (benefit) for income taxes	(139.3)	(3.6)
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	161.9	31.5
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(0.2)	(0.9)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	161.7	30.6
Net Income (Loss) Attributable to Noncontrolling Interest	0.0	0.0
Net Income (Loss) Attributable to Parent	161.7	30.6
Other Comprehensive Income (Loss), Net of Tax	1.4	0.8
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	163.1	31.4
Comprehensive income attributable to noncontrolling interest	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	163.1	31.4
Reportable legal entities | Combined Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	398.9	409.5
Cost of revenues	330.8	343.5
Selling, engineering, and administrative expenses	24.5	26.2
Gains on dispositions of property	2.3	1.7
Restructuring Charges	2.2
Cost of revenues and operating costs	355.2	368.0
Total operating profit	43.7	41.5
Other (income) expense	11.6	1.5
Equity in earnings of subsidiaries, net of taxes	8.5	15.4
Income before income taxes	40.6	55.4
Provision (benefit) for income taxes	(0.1)	12.7
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	40.7	42.7
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	0.0	0.0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	40.7	42.7
Net Income (Loss) Attributable to Noncontrolling Interest	0.0	0.0
Net Income (Loss) Attributable to Parent	40.7	42.7
Other Comprehensive Income (Loss), Net of Tax	0.0	0.0
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	40.7	42.7
Comprehensive income attributable to noncontrolling interest	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	40.7	42.7
Reportable legal entities | Combined Non-Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	264.2	261.0
Cost of revenues	206.7	194.0
Selling, engineering, and administrative expenses	15.7	12.7
Gains on dispositions of property	7.2	8.3
Restructuring Charges	(3.1)
Cost of revenues and operating costs	212.1	198.4
Total operating profit	52.1	62.6
Other (income) expense	46.3	45.5
Equity in earnings of subsidiaries, net of taxes	4.8	5.0
Income before income taxes	10.6	22.1
Provision (benefit) for income taxes	1.2	1.2
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	9.4	20.9
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	0.0	(0.2)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	9.4	20.7
Net Income (Loss) Attributable to Noncontrolling Interest	0.0	0.0
Net Income (Loss) Attributable to Parent	9.4	20.7
Other Comprehensive Income (Loss), Net of Tax	(24.6)	(4.6)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	(15.2)	16.1
Comprehensive income attributable to noncontrolling interest	0.0	0.0
Comprehensive income attributable to Trinity Industries, Inc.	(15.2)	16.1
Eliminations
Condensed Income Statements, Captions [Line Items]
Revenues	(47.9)	(65.7)
Cost of revenues	(57.0)	(75.0)
Selling, engineering, and administrative expenses	0.0	0.0
Gains on dispositions of property	0.0	0.0
Restructuring Charges	0.0
Cost of revenues and operating costs	(57.0)	(75.0)
Total operating profit	9.1	9.3
Other (income) expense	(0.2)	0.0
Equity in earnings of subsidiaries, net of taxes	(68.2)	(74.6)
Income before income taxes	(58.9)	(65.3)
Provision (benefit) for income taxes	(9.4)	(1.4)
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(49.5)	(63.9)
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	0.0	0.0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(49.5)	(63.9)
Net Income (Loss) Attributable to Noncontrolling Interest	0.6	(0.5)
Net Income (Loss) Attributable to Parent	(50.1)	(63.4)
Other Comprehensive Income (Loss), Net of Tax	0.0	0.0
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	(49.5)	(63.9)
Comprehensive income attributable to noncontrolling interest	0.9	(0.2)
Comprehensive income attributable to Trinity Industries, Inc.	$ (50.4)	$ (63.7)