Investments in Affiliated Companies (Share of Affiliate Earnings) (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pre tax share of affiliates earnings by segment
Share of affiliates' earnings (pre-tax)	$ 98.1	$ 45.9	$ 56.5
Provision for Income Taxes, Equity Method Investment	(25.7)	(12.3)	(55.3)
Share of Affiliates' Earnings	72.4	33.6	1.2
Foreign Tax Authority | United Kingdom tax authority
Pre tax share of affiliates earnings by segment
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	39.7		39.7
Rail North America [Member]
Pre tax share of affiliates earnings by segment
Share of affiliates' earnings (pre-tax)	(0.6)	0.5	0.0
Rail International [Member]
Pre tax share of affiliates earnings by segment
Share of affiliates' earnings (pre-tax)	0.0	0.0	0.0
Portfolio Management [Member]
Pre tax share of affiliates earnings by segment
Share of affiliates' earnings (pre-tax)	$ 98.7	$ 45.4	$ 56.5