Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 212.2	$ 156.9	$ 622.0	$ 563.0
Derivative financial instruments:
Unrealized losses arising during the period, net of tax expense (benefit) of $(0.2), $-, $(0.4), and $(0.5)	(0.5)	0.1	(0.8)	(0.9)
Reclassification adjustments for losses included in net income, net of tax benefit of $0.2, $1.9, $3.3, and $6.6	1.2	4.2	7.6	11.9
Currency translation adjustment	(2.6)	(0.6)	(5.2)	(0.6)
Defined benefit plans:
Amortization of net actuarial losses, net of tax benefit of $0.5, $0.3, $1.5, and $0.5	0.8	0.7	2.4	1.1
Other comprehensive income	(1.1)	4.4	4.0	11.5
Comprehensive income	211.1	161.3	626.0	574.5
Less: comprehensive income attributable to noncontrolling interest	8.4	8.6	27.5	25.4
Comprehensive income attributable to Trinity Industries, Inc.	$ 202.7	$ 152.7	$ 598.5	$ 549.1