Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net income (loss)	$ 181.8	$ (226.2)	$ 136.1
Unrealized gains (losses) arising during the period, net of tax benefit (expense) of $(2.8), $5.9, and $3.8	9.2	(19.4)	(12.8)
Reclassification adjustments for losses included in net income (loss), net of tax benefit of $1.2, $3.5, and $0.8	5.4	12.9	4.5
Settlement of pension plan, net of tax benefit of $—, $34.9, and $—	0.0	116.6	0.0
Unrealized gains (losses) arising during the period, net of tax (benefit) expense of $0.1, $2.7, and $(9.0)	0.3	7.7	(30.2)
Amortization of prior service cost, net of tax benefit of $—, $0.3, and $—	0.0	0.9	0.0
Amortization of net actuarial losses, net of tax benefit of $0.1, $1.3, and $1.1	0.2	4.7	3.5
Other comprehensive income (loss):	15.1	123.4	(35.0)
Comprehensive income (loss)	196.9	(102.8)	101.1
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	1.0	(77.7)	(0.2)
Comprehensive income (loss) attributable to Trinity Industries, Inc.	$ 195.9	$ (25.1)	$ 101.3