Railcar Leasing and Management Services Group - Schedule of proceeds from leased railcars (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Property Subject to or Available for Operating Lease [Line Items]
Lease portfolio sales				$ 245.8	$ 514.8
Operating profit on lease portfolio sales (1)		$ 100.2	$ 92.7	268.3	220.5
Operating Segments [Member]
Property Subject to or Available for Operating Lease [Line Items]
Operating profit on lease portfolio sales (1)		127.8	133.9	380.8	333.7
Operating Segments [Member] | Railcar Leasing and Management Services Group [Member]
Property Subject to or Available for Operating Lease [Line Items]
Operating profit on lease portfolio sales (1)	[1]	$ 88.6	$ 107.9	$ 292.6	$ 293.2
Operating Profit Margin		39.80%	55.40%	45.10%	51.20%
Operating Segments [Member] | Sales of Leased Railcars [Domain] | Railcar Leasing and Management Services Group [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease portfolio sales		$ 60.1	$ 299.6	$ 245.8	$ 514.8
Operating profit on lease portfolio sales (1)	[1]	$ 3.1	$ 34.3	$ 46.4	$ 73.0	[2]
Operating Profit Margin		5.20%	11.40%	18.90%	13.90%
Profit recognized at sales-type lease commencement (1)	[3]	$ 0.0	$ 0.0	$ 0.0	$ 1.3
Operating Segments [Member] | Sales of Leased Railcars, Excluding Sales-Type Leases | Railcar Leasing and Management Services Group [Member]
Property Subject to or Available for Operating Lease [Line Items]
Operating profit on lease portfolio sales (1)		$ 3.1	$ 34.3	$ 46.4	$ 71.7	[4]

[1] Operating profit includes: depreciation and amortization; 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 profit 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] Includes $1.3 million selling profit associated with sales-type leases for the nine months ended September 30, 2022.

[3] Included in gains on dispositions of property – lease portfolio sales on our Consolidated Statements of Operations.

[4] Excludes $1.3 million selling profit associated with sales-type leases for the nine months ended September 30, 2022.