Note 6. Railcar Leasing and Management Services Group Selected Leasing Income Statement Information (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Sep. 30, 2020	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues:			$ 1,999.4		$ 3,005.1		$ 2,509.1
Total operating profit (loss)			(124.5)		416.3		315.1
Depreciation and amortization			266.0		283.6		251.9
Operating lease expense			15.8		18.0
Selling, engineering, and administrative expenses:			228.4		262.8		296.6
Interest expense			219.2		221.8		179.3
Reduced Depreciation [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Depreciation and amortization		$ 3.5	7.0
Railcar Leasing and Management Services Group [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues:			802.3		1,117.2		842.8
Total operating profit (loss)			353.7		406.6		351.1
Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total operating profit (loss)			418.2		704.1		558.9
Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues:			$ 802.3		$ 1,117.2		842.8
Revenues, Percent Change			(28.20%)		32.60%
Total operating profit (loss)	[1]		$ 353.7		$ 406.6		$ 351.1
Operating Income (Loss), Percent Change			(13.00%)		15.80%
Operating Profit Margin			44.10%		36.40%		41.70%
Depreciation and amortization			$ 214.7	[2],[3]	$ 232.2		$ 196.6
Depreciation, Depletion, and Amortization, Percent Change			(7.50%)	[2],[3]	18.10%
Cost, Maintenance			$ 88.1		$ 102.1		99.3
Maintenance Costs, Percent Change			(13.70%)		2.80%
Operating lease expense			$ 9.7		$ 16.9		42.4
Operating Leases, Rent Expense, Percent Change			(42.60%)		(60.10%)
Selling, engineering, and administrative expenses:			$ 51.3		$ 49.5		51.1
Selling, Engineering, and Administrative Expense, Percent Change			3.60%		(3.10%)
Interest expense			$ 196.2		$ 197.2		142.3
Interest Expense, Percent Change			(0.50%)		38.60%
Leasing and management [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues:			$ 747.9		$ 756.5		728.9
Total operating profit (loss)			$ 336.0		$ 314.7		$ 291.8
Leasing and management [Member] | Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues, Percent Change			(1.10%)		3.80%
Operating Income (Loss), Percent Change			6.80%		7.80%
Operating Profit Margin			44.90%		41.60%		40.00%
Railcar Owned One Year or Less [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues:			$ 54.4	[4]	$ 360.7	[5]	$ 113.9
Total operating profit (loss)			$ 0.4		$ 41.4		$ 21.5
Operating Profit Margin			0.70%		11.50%		18.90%
Railcar Owned One Year or Less [Member] | Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues, Percent Change			(84.90%)		216.70%
Operating Income (Loss), Percent Change			(65.70%)		0.20%
Railcar Owned Greater than One Year [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Revenues:			$ 138.7		$ 205.7		$ 230.5
Total operating profit (loss)			$ 17.3		$ 50.5		$ 50.4
Operating Profit Margin			12.50%		24.60%		21.90%
Railcar Owned Greater than One Year [Member] | Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Operating Income (Loss), Percent Change			(99.00%)		92.60%
Property Disposition Gain (Loss) [Member] | Railcar Leasing and Management Services Group [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total operating profit (loss)			$ 0.0		$ 0.0		$ (12.6)	[6]

[1] Operating profit includes: depreciation; maintenance and compliance; rent; 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.

[2] As a result of the impairment of long-lived assets related to our small cube covered hopper railcars recorded in the second quarter of 2020, our quarterly depreciation expense beginning in the third quarter of 2020 has decreased by approximately $3.5 million, for a total reduction of $7.0 million for the year ended December 31, 2020

[3] Effective January 1, 2020, we revised the estimated useful lives and salvage values of certain railcar types in our lease fleet. This change in estimate resulted in a decrease in depreciation expense in the year ended December 31, 2020 of approximately $30.8 million. This decrease was partially offset by higher depreciation associated with growth in the lease fleet. See Note 1 for further information.

[4] Beginning in the fourth quarter of 2020, we made a prospective change in the presentation of sales of railcars from the lease fleet. See Note 1 for more information.

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

[6] Property disposition losses for the year ended December 31, 2018 included a non-cash charge of $12.6 million associated with our election to forego the early purchase options contained in certain lease agreements.