Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 8.5	$ 4.8	$ 10.4	$ 6.1
Derivative financial instruments:
Unrealized gains (losses) arising during the period, net of tax benefit (expense) of $(1.0), $0.3, $(5.4), and $(1.7)	2.1	(0.4)	16.8	5.8
Reclassification adjustments for losses included in net income, net of tax benefit (expense) of $0.4, $(0.6),$1.3, and $0.3	1.9	2.0	4.4	1.1
Defined benefit plans:
Amortization of net actuarial losses, net of tax benefit of $—, $0.1, $—, and $0.1	0.0	0.0	0.1	0.1
Foreign Currency Translation [Abstract]
Reclassification adjustments for losses included in discontinued operations, net of tax benefit of $—, $—, $—, and $—	1.3	0.0	1.3	0.0
Other Comprehensive Income (Loss), Net of Tax, Total	5.3	1.6	22.6	7.0
Comprehensive income	13.8	6.4	33.0	13.1
Less: comprehensive income (loss) attributable to noncontrolling interest	3.8	(7.5)	6.6	(9.2)
Comprehensive income attributable to Trinity Industries, Inc.	$ 10.0	$ 13.9	$ 26.4	$ 22.3