Accumulated Other Comprehensive Loss (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Comprehensive net income (loss)
Net income (loss) attributable to Trinity Industries, Inc.	$ 56.1	$ 31.9	$ 30.0	$ 24.2	$ 17.3	$ 29.7	$ 18.4	$ 2.0	$ 142.2	$ 67.4	$ (137.7)
Other comprehensive income (loss):
Change in funded status of pension liability, net of tax expense (benefit) of $(16.9), $5.2, and $20.9									(28.6)	8.7	35.6
Change in unrealized (loss) gain on derivative financial instruments, net of tax (benefit) expense of $0.4, $(2.6) and $14.2									0.2	(16.4)	27.8
Trinity Stockholders' Equity [Member]
Comprehensive net income (loss)
Net income (loss) attributable to Trinity Industries, Inc.									142.2	67.4	(137.7)
Other comprehensive income (loss):
Change in funded status of pension liability, net of tax expense (benefit) of $(16.9), $5.2, and $20.9									(28.6)	8.7	35.6
Change in unrealized (loss) gain on derivative financial instruments, net of tax (benefit) expense of $0.4, $(2.6) and $14.2									0.1	(7.3)	27.8
Other changes, net of tax benefit of $0, $0.7, and $(0.0)										1.1	(0.1)
Comprehensive net income									$ 113.7	$ 69.9	$ (74.4)