Quarterly Financial Data (Unaudited) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended											12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Data [Abstract]
Revenues	$ 642.5	$ 677.5	$ 649.7		$ 607.4		$ 615.6	$ 621.6	$ 579.3		$ 552.8	$ 2,577.1	$ 2,369.3	$ 2,238.6
Operating income	213.9	229.4	205.8	[1]	160.0	[2]	196.1	200.3	179.3		162.9	809.1	738.6	715.9
Net income	141.7	138.4	130.2		94.0		114.4	119.0	15.7	[3]	104.2	504.3	353.3	379.4
Net income attributable to Kansas City Southern and subsidiaries	141.0	138.1	129.8		93.7		113.8	118.4	15.4	[3]	103.8	502.6	351.4	377.3
Per share data:
Basic earnings per common share	$ 1.28	$ 1.25	$ 1.18		$ 0.85		$ 1.03	$ 1.08	$ 0.14		$ 0.94	$ 4.56	$ 3.19	$ 3.44
Diluted earnings per common share	$ 1.28	$ 1.25	$ 1.18		$ 0.85		$ 1.03	$ 1.07	$ 0.14		$ 0.94	$ 4.55	$ 3.18	$ 3.43
Lease termination costs included in operating expenses			8.4		29.9							38.3	0	0
Debt retirement costs									$ (111.4)			$ (6.6)	$ (119.2)	$ (20.1)

[1] During the second quarter of 2014, the Company recognized pre-tax lease termination costs of $8.4 million, due to the early termination of certain operating leases and the related purchase of equipment.

[2] During the first quarter of 2014, the Company recognized pre-tax lease termination costs of $29.9 million, due to the early termination of certain operating leases and the related purchase of equipment.

[3] During the second quarter of 2013, the Company recognized pre-tax debt retirement costs of $111.4 million, related to debt restructuring activities that occurred during the period.