Note 11. Employee Retirement Plans Employee Retirement Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 10.1
Defined Benefit Plan, Plan Assets, Administration Expense		$ 0.2	$ 2.5
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Settlement			6.4
Assets for Plan Benefits, Defined Benefit Plan			16.6
Defined Benefit Plan, Plan Assets, Period Increase (Decrease)	(0.4)		(16.0)
Defined Benefit Plan, Excise Tax from Reversion of Surplus Plan Assets	0.1		3.2
Trinity Industries, Inc. Consolidated Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Employer Discretionary Contribution Amount			10.9
Defined Benefit Plan, Plan Assets, Amount	$ 0.0	$ 0.4	$ 0.6