Operating Assets and Facilities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 13,320.1		$ 13,081.9
Less: allowance for depreciation	(3,700.3)		(3,670.7)
Operating assets and facilities, net	9,619.8		9,411.2
Total depreciation expense	100.5	$ 93.5
Railcars and locomotives
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	11,967.7		11,700.8
Aircraft spare engines
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	769.7		769.7
Tank containers
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	237.8		237.7
Buildings, leasehold improvements, and other equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	250.7		253.0
Other
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 94.2		$ 120.7