Summary of Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2013
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The foregoing consolidated financial statements are unaudited and have been prepared from the books and records of Trinity Industries, Inc. and its consolidated subsidiaries (“Trinity”, “Company”, “we”, or “our”) including the accounts of its wholly-owned subsidiaries and its partially-owned subsidiary, TRIP Rail Holdings LLC (“TRIP Holdings”), in which the Company has a controlling interest. In our opinion, all normal and recurring adjustments necessary for a fair presentation of the financial position of the Company as of March 31, 2013, and the results of operations and cash flows for the three month periods ended March 31, 2013 and 2012, have been made in conformity with generally accepted accounting principles. All significant intercompany accounts and transactions have been eliminated. Certain amounts previously reported have been adjusted in the accompanying consolidated financial statements to remove the effects of discontinued operations. See Note 2 Acquisitions and Divestitures. Because of seasonal and other factors, the results of operations for the three month period ended March 31, 2013 may not be indicative of expected results of operations for the year ending December 31, 2013. These interim financial statements and notes are condensed as permitted by the instructions to Form 10-Q and should be read in conjunction with the audited consolidated financial statements of the Company included in its Form 10-K for the year ended December 31, 2012.
Stockholders' Equity	Stockholders' Equity In September 2012, the Company’s Board of Directors authorized a new $200 million share repurchase program, effective October 1, 2012, which expires on December 31, 2014. No shares were repurchased under the program during the three months ended March 31, 2013.
Revenue Recognition	Revenue Recognition Revenues for contracts providing for a large number of units and few deliveries are recorded as the individual units are produced, inspected, and accepted by the customer as the risk of loss passes to the customer upon pre-delivery acceptance on these contracts. This occurs primarily in the Rail and Inland Barge Groups. Revenue from rentals and operating leases, including contracts which contain non-level fixed rental payments, is recognized monthly on a straight-line basis. Revenue is recognized from the sales of railcars from the lease fleet on a gross basis in leasing revenues and cost of revenues if the railcar has been owned by the lease fleet for one year or less at the time of sale. Sales of railcars from the lease fleet that have been owned by the lease fleet for more than one year are recognized as a net gain or loss from the disposal of a long-term asset. Fees for shipping and handling are recorded as revenue. For all other products, we recognize revenue when products are shipped or services are provided.
Financial Instruments	Financial Instruments The Company considers all highly liquid debt instruments to be either cash and cash equivalents if purchased with a maturity of three months or less, or short-term marketable securities if purchased with a maturity of more than three months and less than one year. The Company intends to hold its short-term marketable securities until they are redeemed at their maturity date and believes it is not more likely than not that the Company will be required to sell the securities before recovery of their amortized cost bases, which may be maturity. Financial instruments that potentially subject the Company to a concentration of credit risk are primarily cash investments including restricted cash, short-term marketable securities, and receivables. The Company places its cash investments and short-term marketable securities in bank deposits and investment grade, short-term debt instruments and limits the amount of credit exposure to any one commercial issuer. Concentrations of credit risk with respect to receivables are limited due to control procedures that monitor the credit worthiness of customers, the large number of customers in the Company's customer base, and their dispersion across different industries and geographic areas. As receivables are generally unsecured, the Company maintains an allowance for doubtful accounts based upon the expected collectability of all receivables. Receivable balances determined to be uncollectible are charged against the allowance. The carrying values of cash, short-term marketable securities, receivables and accounts payable are considered to be representative of their respective fair values. At March 31, 2013, one customer’s net receivable balance in our Energy Equipment Group, all within terms, accounted for 14% of the consolidated net receivables balance outstanding.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In February 2013, the Financial Accounting Standards Board issued Accounting Standards Update No. 2013-02, "Reporting of Amounts Reclassified out of Accumulated Other Comprehensive Income," ("ASU 2013-02") which amended prior reporting requirements with respect to comprehensive income by requiring additional disclosures about the amounts reclassified out of accumulated other comprehensive loss by component. ASU 2013-02 became effective for public companies during interim and annual reporting periods beginning after December 15, 2012 with early adoption permitted. Accordingly, the Company adopted this new standard on January 1, 2013. The adoption of ASU 2013-02 did not have an impact on the Company's consolidated financial position, results of operations, or cash flows.
Reclassifications	Reclassifications Certain prior year balances have been reclassified in the Consolidated Statements of Operations, Consolidated Balance Sheets, and Consolidated Statements of Cash Flows to conform to the 2013 presentation.

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2013

The foregoing consolidated financial statements are unaudited and have been prepared from the books and records of Trinity Industries, Inc. and its consolidated subsidiaries (“Trinity”, “Company”, “we”, or “our”) including the accounts of its wholly-owned subsidiaries and its partially-owned subsidiary, TRIP Rail Holdings LLC (“TRIP Holdings”), in which the Company has a controlling interest. In our opinion, all normal and recurring adjustments necessary for a fair presentation of the financial position of the Company as of March 31, 2013, and the results of operations and cash flows for the three month periods ended March 31, 2013 and 2012, have been made in conformity with generally accepted accounting principles. All significant intercompany accounts and transactions have been eliminated. Certain amounts previously reported have been adjusted in the accompanying consolidated financial statements to remove the effects of discontinued operations. See Note 2 Acquisitions and Divestitures. Because of seasonal and other factors, the results of operations for the three month period ended March 31, 2013 may not be indicative of expected results of operations for the year ending December 31, 2013. These interim financial statements and notes are condensed as permitted by the instructions to Form 10-Q and should be read in conjunction with the audited consolidated financial statements of the Company included in its Form 10-K for the year ended December 31, 2012.

Stockholders' Equity

In September 2012, the Company’s Board of Directors authorized a new $200 million share repurchase program, effective October 1, 2012, which expires on December 31, 2014. No shares were repurchased under the program during the three months ended March 31, 2013.

Revenue Recognition

Revenues for contracts providing for a large number of units and few deliveries are recorded as the individual units are produced, inspected, and accepted by the customer as the risk of loss passes to the customer upon pre-delivery acceptance on these contracts. This occurs primarily in the Rail and Inland Barge Groups. Revenue from rentals and operating leases, including contracts which contain non-level fixed rental payments, is recognized monthly on a straight-line basis. Revenue is recognized from the sales of railcars from the lease fleet on a gross basis in leasing revenues and cost of revenues if the railcar has been owned by the lease fleet for one year or less at the time of sale. Sales of railcars from the lease fleet that have been owned by the lease fleet for more than one year are recognized as a net gain or loss from the disposal of a long-term asset. Fees for shipping and handling are recorded as revenue. For all other products, we recognize revenue when products are shipped or services are provided.

Financial Instruments

The Company considers all highly liquid debt instruments to be either cash and cash equivalents if purchased with a maturity of three months or less, or short-term marketable securities if purchased with a maturity of more than three months and less than one year. The Company intends to hold its short-term marketable securities until they are redeemed at their maturity date and believes it is not more likely than not that the Company will be required to sell the securities before recovery of their amortized cost bases, which may be maturity.

Financial instruments that potentially subject the Company to a concentration of credit risk are primarily cash investments including restricted cash, short-term marketable securities, and receivables. The Company places its cash investments and short-term marketable securities in bank deposits and investment grade, short-term debt instruments and limits the amount of credit exposure to any one commercial issuer. Concentrations of credit risk with respect to receivables are limited due to control procedures that monitor the credit worthiness of customers, the large number of customers in the Company's customer base, and their dispersion across different industries and geographic areas. As receivables are generally unsecured, the Company maintains an allowance for doubtful accounts based upon the expected collectability of all receivables. Receivable balances determined to be uncollectible are charged against the allowance. The carrying values of cash, short-term marketable securities, receivables and accounts payable are considered to be representative of their respective fair values. At March 31, 2013, one customer’s net receivable balance in our Energy Equipment Group, all within terms, accounted for 14% of the consolidated net receivables balance outstanding.

Recent Accounting Pronouncements

In February 2013, the Financial Accounting Standards Board issued Accounting Standards Update No. 2013-02, "Reporting of Amounts Reclassified out of Accumulated Other Comprehensive Income," ("ASU 2013-02") which amended prior reporting requirements with respect to comprehensive income by requiring additional disclosures about the amounts reclassified out of accumulated other comprehensive loss by component. ASU 2013-02 became effective for public companies during interim and annual reporting periods beginning after December 15, 2012 with early adoption permitted. Accordingly, the Company adopted this new standard on January 1, 2013. The adoption of ASU 2013-02 did not have an impact on the Company's consolidated financial position, results of operations, or cash flows.

Reclassifications

Certain prior year balances have been reclassified in the Consolidated Statements of Operations, Consolidated Balance Sheets, and Consolidated Statements of Cash Flows to conform to the 2013 presentation.

- Definition

Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting. The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary.

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+ Details

- Definition

Disclosure of accounting policy for revenue recognition. If the entity has different policies for different types of revenue transactions, the policy for each material type of transaction is generally disclosed. If a sales transaction has multiple element arrangements (for example, delivery of multiple products, services or the rights to use assets) the disclosure may indicate the accounting policy for each unit of accounting as well as how units of accounting are determined and valued. The disclosure may encompass important judgment as to appropriateness of principles related to recognition of revenue. The disclosure also may indicate the entity's treatment of any unearned or deferred revenue that arises from the transaction.

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- Definition

Disclosure of accounting policy for its capital stock transactions, including dividends and accumulated other comprehensive income.

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