Quarterly Financial Data (Unaudited) (Details) - USD ($)	3 Months Ended																12 Months Ended
	Dec. 31, 2022		Sep. 30, 2022		Jun. 30, 2022		Mar. 31, 2022		Dec. 31, 2021		Sep. 30, 2021		Jun. 30, 2021		Mar. 31, 2021		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Quarterly Financial Data Disclosure [Line Items]
Revenues	$ 864,500,000		$ 882,200,000		$ 845,500,000		$ 778,200,000		$ 747,800,000		$ 744,000,000.0		$ 749,500,000		$ 706,000,000.0		$ 3,370,400,000	$ 2,947,300,000	$ 2,632,600,000
Operating income (loss)	298,200,000	[1]	325,000,000.0	[1]	312,800,000	[1]	291,100,000	[1]	810,600,000	[2]	251,900,000	[2]	(431,700,000)	[2]	253,000,000.0	[2]	1,227,100,000	883,800,000	1,003,000,000
Net income (loss)	400,000,000.0	[3]	201,700,000		194,100,000		188,000,000.0		595,100,000		156,500,000		(378,000,000.0)		153,400,000		983,800,000	527,000,000.0	619,100,000
Net income (loss) attributable to Kansas City Southern and subsidiaries	399,400,000		201,300,000		194,100,000		187,400,000		594,500,000		156,200,000		(378,500,000)		153,000,000.0		982,200,000	525,200,000	617,000,000.0
Net merger costs (income)	9,800,000		$ 11,500,000		$ 12,500,000		$ 12,800,000		$ (512,600,000)		$ 36,500,000		$ 720,800,000		$ 19,300,000		46,600,000	264,000,000	0
Gain on settlement of treasury lock agreements	$ 259,300,000																259,300,000	0	0
Cash payments for merger costs																	34,100,000	2,287,200,000	0
Reimbursement of merger termination fees																	$ 0	2,100,000,000	$ 0
Merger Termination Fee [Member] | Merger Costs, Net [Member]
Quarterly Financial Data Disclosure [Line Items]
Cash payments for merger costs																		1,400,000,000
Reimbursement of merger termination fees																		$ 1,400,000,000

[1] During the first, second, third and fourth quarters of 2022, the Company recognized pre-tax net merger costs of $12.8 million, $12.5 million, $11.5 million, and $9.8 million, respectively, related to the Company’s merger with CP.

[2] During the first, second, third and fourth quarters of 2021, the Company recognized pre-tax net merger costs (income) of $19.3 million, $720.8 million, $36.5 million, and $(512.6) million, respectively, related to the Company’s various merger activities. The large fluctuations between the quarters are driven by the recognition and reversal of merger termination fees. For the year ended December 31, 2021, KCS incurred $1,400.0 million of merger termination fees, completely offset by the recovery of $1,400.0 million of merger termination fees recognized in merger costs, net within the consolidated statements of income. See more details in Note 3, Merger Agreement.

[3] During the fourth quarter of 2022, the Company recognized the gain on settlement of the interest rate derivative instruments of $259.3 million. Refer to Note 10, Derivative Instruments for more information.