Net Income Attributable to Trinity industries, Inc. Per Common Share (Details) (USD $) In Millions, except Per Share data	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Net Income Attributable to Trinity industries, Inc. Per Common Share [Abstract]
Net income attributable to Trinity Industries, Inc.	$ 30.0	$ 18.4	$ 54.2	$ 20.4
Unvested restricted share participation	(1.0)	(0.6)	(1.9)	(0.7)
Net income attributable to Trinity Industries, Inc. - basic	29.0	17.8	52.3	19.7
Net income attributable to Trinity Industries, Inc. - basic, Average Shares	77.4	76.7	77.2	76.6
Net income attributable to Trinity Industries, Inc. - basic, EPS	$ 0.37	$ 0.23	$ 0.68	$ 0.26
Stock options	0.3	0.2	0.3	0.1
Net income attributable to Trinity Industries, Inc - diluted	$ 29.0	$ 17.8	$ 52.3	$ 19.7
Net income attributable to Trinity Industries, Inc. - diluted, Average Shares	77.7	76.9	77.5	76.7
Net income attributable to Trinity Industries, Inc. - diluted, EPS	$ 0.37	$ 0.23	$ 0.67	$ 0.26
Net Income Per Common Share (Textuals) [Abstract]
Total weighted average restricted shares and antidilutive stock options	3.0	2.8	3.0	2.7

Income Loss From Continuing Operations Attributable To Parent Company Basic.

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Income Loss From Continuing Operations Attributable To Parent Company Diluted.

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Net Income Per Common Share.

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Assumption that stock options or restrictive stock units were exercised for computing the dilutive effect of convertible securities.

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-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) in the future that were not included in the computation of diluted EPS because to do so would increase EPS amounts or decrease loss per share amounts for the period presented.

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The amount of net income or loss for the period per each share of common stock and dilutive common stock equivalents outstanding during the reporting period.

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This element represents the income or loss from continuing operations attributable to the reporting entity which may also be defined as revenue less expenses and taxes from ongoing operations before extraordinary items and cumulative effects of changes in accounting principles, but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests, if any.

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The amount of income (loss) from continuing operations per each share of common stock outstanding during the reporting period.

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Aggregate awards of share options and nonvested shares to be issued to an employee under a share-based compensation arrangement are considered options for purposes of computing diluted earnings per share. Such share-based awards shall be considered to be outstanding as of the grant date for purposes of computing diluted earnings per share even though their exercise may be contingent upon vesting. Those share-based awards are included in the diluted Earnings Per Share (EPS) computation even if the employee may not receive (or be able to sell) the stock until some future date. Accordingly, all shares to be issued shall be included in computing diluted EPS if the effect is dilutive. The dilutive effect of share-based compensation arrangements shall be computed using the treasury stock method. If the equity share options or other equity instruments are outstanding for only part of a period, the shares issuable shall be weighted to reflect the portion of the period during which the equity instruments were outstanding.

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The average number of shares issued and outstanding that are used in calculating diluted EPS, determined based on the timing of issuance of shares in the period.

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

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