Consolidated Statement of Stockholders' Equity (unaudited) - 6 months ended Jun. 30, 2015 - USD ($) $ in Millions	Total		Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Trinity Stockholders' Equity	Noncontrolling Interest
Beginning balance, Shares at Dec. 31, 2014			155,700,000				(100,000)
Beginning balance at Dec. 31, 2014	$ 3,397.4		$ 155.7	$ 463.2	$ 2,489.9	$ (111.9)	$ (1.0)	$ 2,995.9	$ 401.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	409.8				392.2			392.2	17.6
Other comprehensive income	5.1					3.6		3.6	1.5
Cash dividends on common stock	(32.5)				(32.5)			(32.5)
Restricted shares, net, Shares			2,100,000				(900,000)
Restricted shares, net	$ 4.1		$ 0.0	32.8			$ (28.7)	4.1
Shares repurchased, Shares	(2,390,804)						(2,400,000)
Shares repurchased	$ (75.0)						$ (75.0)	(75.0)
Stock options exercised, Shares			0
Stock options exercised	0.2		$ 0.0	0.2				0.2
Excess tax benefits from stock-based compensation	12.1			12.1				12.1
Distributions to noncontrolling interest	(19.9)							0.0	(19.9)
Retirement of treasury stock, Shares			(3,300,000)				3,300,000
Retirement of treasury stock	0.0		$ 0.0	(103.7)			$ 103.7	0.0
Change in par value of common stock	0.0		$ (154.2)	154.2				0.0
Ending balance, Shares at Jun. 30, 2015			154,500,000				(100,000)
Ending balance at Jun. 30, 2015	$ 3,701.3	[1]	$ 1.5	$ 558.8	$ 2,849.6	$ (108.3)	$ (1.0)	$ 3,300.6	$ 400.7

[1] (unaudited)