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Description of Business (Details) $ in Millions	3 Months Ended				6 Months Ended		12 Months Ended
Description of Business (Details) $ in Millions	Jun. 30, 2023 USD ($) AircraftEngines	Mar. 31, 2023 USD ($) AircraftEngines	Sep. 30, 2022 AircraftEngines	Jun. 30, 2022 USD ($) AircraftEngines	Jun. 30, 2023 USD ($) AircraftEngines Segment	Jun. 30, 2022 USD ($) AircraftEngines	Dec. 31, 2022 USD ($)
Schedule of Equity Method Investments [Line Items]
Number of business segments \| Segment					3
Net gain on asset dispositions	$ 41.1			$ (24.2)	$ 88.2	$ 49.5
Number of Specialized Gas Vessels Sold \| AircraftEngines	1	1
Asset Impairment Charges	$ 0.0			31.5	1.2	31.5
Portfolio Investments and Capital Additions	$ 486.6			$ 314.1	$ 873.6	$ 684.5
Number of Aircraft Engines Acquired \| AircraftEngines	9
Number of Specialized Gas Vessels \| AircraftEngines	1	2		5	1	5
Portfolio Management
Schedule of Equity Method Investments [Line Items]
Number of Specialized Gas Vessels Sold \| AircraftEngines		1	2
Asset Impairment Charges	$ 0.0	$ 1.2		$ 31.5	$ 1.2	$ 31.5	$ 34.3
Portfolio Investments and Capital Additions	$ 239.0			0.0	239.0	0.0
Number of Aircraft Engines Acquired \| AircraftEngines	9
Rail International
Schedule of Equity Method Investments [Line Items]
Asset Impairment Charges					0.0		$ 14.6
Portfolio Investments and Capital Additions	$ 77.3			$ 48.8	$ 158.4	$ 127.7