Operating Assets and Facilities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 15,264.4		$ 15,264.4		$ 14,330.6
Less: allowance for depreciation	(4,184.7)		(4,184.7)		(3,880.9)
Operating assets and facilities, net	11,079.7		11,079.7		10,449.7
Total depreciation expense	114.3	$ 108.0	334.6	$ 311.5
Railcars and locomotives
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	13,413.0		13,413.0		12,702.9
Aircraft spare engines
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,177.5		1,177.5		1,030.4
Tank containers
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	278.2		278.2		241.4
Buildings, leasehold improvements, and other equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	288.0		288.0		265.3
Other
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 107.7		$ 107.7		$ 90.6