Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenues	$ 744.0	$ 659.6	$ 2,199.5	$ 1,939.2
Operating expenses:
Compensation and benefits	133.3	117.4	391.2	354.6
Purchased services	51.4	47.3	161.0	145.2
Fuel	78.0	50.8	227.9	165.2
Equipment costs	19.6	23.9	64.8	63.9
Depreciation and amortization	90.5	89.2	273.7	267.9
Materials and other	82.8	59.0	231.1	184.7
Merger costs	36.5	0.0	776.6	0.0
Restructuring charges	0.0	0.5	0.0	17.0
Total operating expenses	492.1	388.1	2,126.3	1,198.5
Operating income	251.9	271.5	73.2	740.7
Equity in net earnings (losses) of affiliates	3.8	(1.3)	13.2	(0.1)
Interest expense	(39.0)	(39.5)	(117.1)	(111.8)
Foreign exchange gain (loss)	(0.5)	7.7	(1.0)	(44.0)
Other income, net	0.5	0.3	0.7	2.5
Income (loss) before income taxes	216.7	238.7	(31.0)	587.3
Income tax expense	60.2	48.5	37.1	134.5
Net income (loss)	156.5	190.2	(68.1)	452.8
Less: Net income attributable to noncontrolling interest	0.3	0.4	1.2	1.5
Net income (loss) attributable to Kansas City Southern and subsidiaries	156.2	189.8	(69.3)	451.3
Preferred stock dividends	0.1	0.1	0.2	0.2
Net income (loss) available to common stockholders	$ 156.1	$ 189.7	$ (69.5)	$ 451.1
Earnings (loss) per share:
Basic earnings (loss) per share	$ 1.72	$ 2.02	$ (0.76)	$ 4.76
Diluted earnings (loss) per share	$ 1.71	$ 2.01	$ (0.76)	$ 4.74
Average shares outstanding (in thousands):
Basic	90,806	93,876	90,777	94,672
Effect of dilution	566	504	0	477
Diluted	91,372	94,380	90,777	95,149