Investments in Affiliated Companies (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Alpha Partners Leasing Limited [Domain]
Equity Method Investment, Summarized Financial Information. Revenue.	$ 112.5	$ 94.0	$ 318.5	$ 283.5
Equity Method Investment, Summarized Financial Information, Other Expenses	(95.9)	(75.1)	(271.0)	(227.7)
Equity Method Investment, Summarized Financial Information, Gains (Losses)	10.0	6.8	48.2	33.1
RRPF Joint Ventures [Member]
Equity Method Investment, Summarized Financial Information, Net Income (Loss)	$ 21.7	$ 20.8	$ 77.6	$ 72.0