Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 1.9	$ 1.3
Derivative financial instruments:
Unrealized gains arising during the period, net of tax expense of $4.4 and $2.0	14.7	6.2
Reclassification adjustments for (gains) losses included in net income, net of tax benefit of $0.9 and $0.9	2.5	(0.9)
Defined benefit plans:
Amortization of net actuarial losses, net of tax benefit of $— and $—	0.1	0.1
Other Comprehensive Income (Loss), Net of Tax, Total	17.3	5.4
Comprehensive income	19.2	6.7
Less: comprehensive income (loss) attributable to noncontrolling interest	2.8	(1.7)
Comprehensive income attributable to Trinity Industries, Inc.	$ 16.4	$ 8.4