Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 826.0	$ 709.3	$ 392.4
Derivative financial instruments:
Unrealized gains/(losses) arising during the period, net of tax expense/ (benefit) of $(0.2), $(0.6), and $0.8	(0.7)	(1.2)	0.8
Reclassification adjustments for losses included in net income, net of tax benefit of $3.4, $8.4, and $8.7	9.0	16.0	18.1
Currency translation adjustment	(6.0)	(2.0)	0.0
Defined benefit plans:
Unrealized gains/(losses) arising during the period, net of tax expense/ (benefit) of $(3.4), $(26.7), and $31.0	(6.0)	(45.1)	52.7
Amortization of net actuarial losses, net of tax benefit of $1.8, $0.8, and $1.9	3.2	1.3	3.1
Total other comprehensive income (loss)	(0.5)	(31.0)	74.7
Comprehensive income	825.5	678.3	467.1
Less: comprehensive income attributable to noncontrolling interest	32.5	34.1	21.1
Comprehensive income attributable to Trinity Industries, Inc.	$ 793.0	$ 644.2	$ 446.0