Note 6. Railcar Leasing and Management Services Group Proceeds from Sale of Railcars (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021		Dec. 31, 2020	Dec. 31, 2019
Property Subject to or Available for Operating Lease [Line Items]
Revenues		$ 472.2	$ 419.8	$ 293.3	$ 330.7	$ 359.7	$ 396.8	$ 439.9	$ 553.3	$ 1,516.0		$ 1,749.7	$ 2,752.4
Operating Income (Loss)		$ 69.2	$ 78.3	$ 57.8	$ 51.5	$ 30.4	$ 64.0	$ (316.3)	$ 67.3	256.8		(154.6)	396.8
Railcar Leasing and Management Services Group [Member]
Property Subject to or Available for Operating Lease [Line Items]
Revenues										735.3		802.3	1,117.2
Operating Income (Loss)										350.9		353.7	406.6
Sales of Leased Railcars [Domain] | Railcar Leasing and Management Services Group [Member]
Property Subject to or Available for Operating Lease [Line Items]
Revenues										460.7		193.1	566.4	[1]
Operating Income (Loss)										$ 54.1	[2]	$ 17.7	$ 91.9	[1]
Operating Profit Margin										11.70%		9.20%	16.20%
Railcar Owned One Year or Less [Member] | Railcar Leasing and Management Services Group [Member]
Property Subject to or Available for Operating Lease [Line Items]
Revenues										$ 0.0	[2]	$ 54.4	$ 360.7	[1]
Operating Segments [Member]
Property Subject to or Available for Operating Lease [Line Items]
Operating Income (Loss)										355.6		390.0	684.2
Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Property Subject to or Available for Operating Lease [Line Items]
Revenues										735.3		802.3	1,117.2
Operating Income (Loss)	[3]									$ 350.9		$ 353.7	$ 406.6
Operating Profit Margin										47.70%		44.10%	36.40%

[1] Includes revenues associated with sales-type leases of $160.5 million for the year ended December 31, 2019.

[2] Beginning in the fourth quarter of 2020, we made a prospective change in the presentation of sales of railcars from the lease fleet. Therefore, all railcar sales for the year ended December 31, 2021 are presented as a net gain or loss from the disposal of a long-term asset regardless of the age of railcar that is sold. See Note 1 for more information.

[3] Operating profit includes: depreciation; fleet operating costs, which include maintenance, compliance, freight, and storage; rent and ad valorem taxes; and selling, engineering, and administrative expenses. Amortization of deferred profit on railcars sold from the Rail Products Group to the Leasing Group is included in the operating profits of the Leasing Group, resulting in the recognition of depreciation expense based on our original manufacturing cost of the railcars. Interest expense is not a component of operating profit and includes the effect of hedges.