Note 9. Debt Components and Fair Value of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	$ 5,754.2	$ 5,607.6
Long-term Debt, Fair Value	5,542.3	5,244.3
Recourse
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	794.6	624.1
Nonrecourse
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	4,959.6	4,983.5
Corporate Segment [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	799.9	624.9
Unamortized Debt Issuance Expense	5.3	0.8
Long-term Debt, Fair Value	812.1	612.5
Corporate Segment [Member] | Recourse
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	794.6	624.1
Wholly Owned Subsidiaries [Member] | Nonrecourse
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	3,819.2	3,800.7
Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	3,836.5	3,821.8
Unamortized Debt Issuance Expense	17.3	21.1
Long-term Debt, Fair Value	3,686.2	3,607.5
Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member] | Nonrecourse
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	3,819.2	3,800.7
Partially-Owned Subsidiaries [Member] | Nonrecourse
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	1,140.4	1,182.8
Partially-Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	1,147.8	1,192.6
Unamortized Debt Issuance Expense	7.4	9.8
Long-term Debt, Fair Value	1,044.0	1,024.3
Partially-Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member] | Nonrecourse
Debt Instrument [Line Items]
Debt, Long-Term and Short-Term, Combined Amount	1,140.4	1,182.8
2009 Secured Railcar Equipment Notes [Member] | Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Non-Recourse Debt, Gross	99.7	115.8
Long-term Debt, Fair Value	100.3	116.6
2010 Secured Railcar Equipment Notes [Member] | Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Non-Recourse Debt, Gross	181.2	204.1
Long-term Debt, Fair Value	176.5	197.1
2018 Secured Railcar Equipment Notes [Domain] | Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	378.0	398.9
Debt Instrument, Unamortized Discount	(0.1)	(0.1)
Long-term Debt, Fair Value	355.2	360.9
2019 Secured Railcar Equipment Notes [Domain] | Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	748.5	786.0
Debt Instrument, Unamortized Discount	(0.1)	(0.2)
Long-term Debt, Fair Value	709.4	716.9
2020 Secured Railcar Equipment Notes [Domain] | Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	311.3	330.4
Debt Instrument, Unamortized Discount	0.0	0.0
Long-term Debt, Fair Value	277.9	284.6
2021 Secured Railcar Equipment Notes [Domain] | Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	295.3	307.7
Debt Instrument, Unamortized Discount	0.0	0.0
Long-term Debt, Fair Value	256.9	253.9
2022 Secured Railcar Equipment Notes [Domain] | Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	232.7	241.1
Debt Instrument, Unamortized Discount	0.0	0.0
Long-term Debt, Fair Value	220.2	239.7
Other Equipment Financing | Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value	52.3	0.0
Secured Debt, Other	52.3	0.0
TRP 2021 Secured Railcar Equipment Notes - RIV 2013 [Member] | Partially-Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	335.1	347.0
Debt Instrument, Unamortized Discount	0.0	0.0
Long-term Debt, Fair Value	296.3	291.8
Triumph Secured Railcar Equipment Notes [Member] | Partially-Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	501.7	523.0
Debt Instrument, Unamortized Discount	(0.1)	(0.2)
Long-term Debt, Fair Value	447.6	451.4
Tribute Secured Railcar Equipment Notes | Partially-Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	311.0	322.6
Debt Instrument, Unamortized Discount	0.0	(0.1)
Long-term Debt, Fair Value	300.1	281.1
Line of Credit [Member] | TRL-2023 Term Loan | Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	334.5	0.0
Long-term Debt, Fair Value	334.5	0.0
4.55% Senior Notes Due October 2024 [Member] | Corporate Segment [Member]
Debt Instrument [Line Items]
Senior Notes	399.9	399.9
Debt Instrument, Unamortized Discount	(0.1)	(0.1)
Long-term Debt, Fair Value	394.5	387.5
7.55% Senior Notes due 2028 | Corporate Segment [Member]
Debt Instrument [Line Items]
Senior Notes	400.0	0.0
Long-term Debt, Fair Value	417.6	0.0
Promissory Notes [Member] | 2017 Secured Railcar Equipment Notes [Domain] | Wholly Owned Subsidiaries [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Debt, Net of Unamortized Discount, Gross of Unamortized Debt Issuance Costs	673.7	716.0
Debt Instrument, Unamortized Discount	(3.5)	(5.6)
Non-Recourse Debt, Gross	677.2
Long-term Debt, Fair Value	673.7	716.0
Revolving Credit Facility [Member] | Line of Credit [Member] | Corporate Segment [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	0.0	225.0
Long-term Debt, Fair Value	0.0	225.0
Revolving Credit Facility [Member] | Line of Credit [Member] | TILC Warehouse Facility [Member] | TILC [Member] | Railcar Leasing and Management Services Group [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	529.3	721.8
Long-term Debt, Fair Value	$ 529.3	$ 721.8