Earnings Per Common Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Net Income Per Common Share (Textual) [Abstract]
Total weighted average restricted shares and antidilutive stock options (in shares)	6.9	7.5
Computation of basic and diluted net income attributable to Trinity Industries, Inc
Net income attributable to Trinity Industries, Inc.	$ 180.2	$ 226.4
Unvested restricted share participation	(5.7)	(7.8)
Net income attributable to Trinity Industries, Inc. – basic	174.5	218.6
Net income from continuing operations attributable to Trinity Industries, Inc. - basic, Average Shares	151.2	150.2
Net income attributable to Trinity Industries, Inc. - basic, EPS	$ 1.15us-gaap_EarningsPerShareBasic	$ 1.46us-gaap_EarningsPerShareBasic
Effect of dilutive securities:
Stock options, Income (Loss)	0	0
Stock options, Average Shares	0	0.1
Convertible Subordinated Notes, Income (Loss)	0.1	0.2
Convertible Subordinated Notes, Average Shares	3.1	3.7
Net income attributable to Trinity Industries, Inc. – diluted	$ 174.6	$ 218.8
Net income from continuing operations attributable to Trinity Industries, Inc. - diluted, Average Shares	154.3	154.0
Net income attributable to Trinity Industries, Inc. - diluted, EPS	$ 1.13us-gaap_EarningsPerShareDiluted	$ 1.42us-gaap_EarningsPerShareDiluted

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Amount of increase (decrease) to net income used for calculating diluted earnings per share (EPS), resulting from the assumed exercise of stock options or restrictive stock units (RSUs).

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Amount of increase (decrease) to net income used for calculating diluted earnings per share (EPS), resulting from the assumed exercise of dilutive convertible securities excluding adjustments related to ESOP convertible preferred stock, stock options, and restrictive stock units.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Amount of income (loss) from continuing operations attributable to the parent. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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Net Income or Loss Available to Common Stockholders plus adjustments resulting from the assumption that dilutive convertible securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.

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Amount of earnings (loss) distributed and earnings (loss) allocated to participating securities for the basic earnings (loss) per share or per unit calculation under the two-class method.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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