Railcar Leasing and Management Services Group - Schedule of proceeds from leased railcars (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022		Jun. 30, 2021
Property Subject to or Available for Operating Lease [Line Items]
Lease portfolio sales				$ 215.2		$ 88.8
Operating profit on lease portfolio sales (1)		$ 73.0	$ 57.8	127.8		109.3
Operating Segments [Member]
Property Subject to or Available for Operating Lease [Line Items]
Operating profit on lease portfolio sales (1)		119.2	84.3	199.8		153.8
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)		$ 105.5	$ 81.1	$ 185.3		$ 159.4
Operating Profit Margin		54.00%	43.80%	49.00%		43.20%
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		$ 144.1	$ 71.5	$ 215.2		$ 88.8
Operating profit on lease portfolio sales (1)		$ 26.9	$ 11.1	$ 38.7	[1]	$ 12.8
Operating Profit Margin		18.70%	15.50%	17.40%		14.40%
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)	[2]			$ 37.4

[1] Includes $1.3 million selling profit associated with sales-type leases for the six months ended June 30, 2022.

[2] Excludes $1.3 million selling profit associated with sales-type leases for the six months ended June 30, 2022.