Railcar Leasing and Services Group - Lease Portfolio Sales (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Property Subject to or Available for Operating Lease [Line Items]
Lease portfolio sales			$ 253.7	$ 245.8
Operating profit on lease portfolio sales	$ 122.4	$ 100.2	379.5	268.3
Operating Segments [Member]
Property Subject to or Available for Operating Lease [Line Items]
Operating profit on lease portfolio sales	164.1	125.2	486.6	374.3
Operating Segments [Member] | Leasing & Services
Property Subject to or Available for Operating Lease [Line Items]
Operating profit on lease portfolio sales	$ 115.2	$ 95.8	$ 343.5	$ 296.5
Operating Profit Margin	39.80%	36.60%	40.10%	38.90%
Operating Segments [Member] | Sales of Leased Railcars [Domain] | Leasing & Services
Property Subject to or Available for Operating Lease [Line Items]
Lease portfolio sales	$ 67.0	$ 60.1	$ 253.7	$ 245.8
Operating Profit Margin	17.00%	5.20%	14.30%	18.90%
Operating Segments [Member] | Sales of Leased Railcars, Excluding Sales-Type Leases | Leasing & Services
Property Subject to or Available for Operating Lease [Line Items]
Operating profit on lease portfolio sales	$ 11.4	$ 3.1	$ 36.2	$ 46.4