Investment in TRIP Holdings (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Trinity Industries Leasing Company (TILC) [Member]
Sales of railcars to TRIP Leasing and related gains
Sales of railcars to TRIP Leasing	$ 0	$ 0	$ 183.8
Railcars owned one year or less at the time of sale	0	0	39.4
Railcars owned for more than one year at the time of sale	0	0	144.4
Recognition of previously deferred gain on sales	0	0	30.3
Deferral of gain on sales of railcars	0	0	7.6
Rail Group [Member]
Sales of railcars to TRIP Leasing and related gains
Sales of railcars to TRIP Leasing	0	0	113.0
Gain on sales of railcars	0	0	11.2
Deferral of gain on sales of railcars	$ 0	$ 0	$ 2.8