Condensed Consolidating Statements of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Condensed Statements of Comprehensive Income [Line Items]
Revenues	$ 656.4	$ 568.5	$ 1,265.9	$ 1,131.2
Operating expenses	417.1	348.6	815.9	723.4
Operating income	239.3	219.9	450.0	407.8
Equity in net earnings (losses) of affiliates	2.9	3.0	6.9	6.9
Interest expense	(25.0)	(24.4)	(49.7)	(48.0)
Foreign exchange gain (loss)	14.2	(24.0)	61.0	(27.5)
Other income (expense), net	(0.1)	(0.7)	1.0	(0.5)
Income before income taxes	231.3	173.8	469.2	338.7
Income tax expense (benefit)	96.6	53.3	187.6	110.1
Net income	134.7	120.5	281.6	228.6
Less: Net income attributable to noncontrolling interest	0.3	0.4	0.6	0.7
Net income attributable to Kansas City Southern and subsidiaries	134.4	120.1	281.0	227.9
Other comprehensive income (loss)	(1.8)	(0.6)	(1.0)	(0.7)
Comprehensive income attributable to Kansas City Southern and subsidiaries	132.6	119.5	280.0	227.2
Condensed Consolidating Financial Information KCS [Member] | Consolidating Adjustments [Member]
Condensed Statements of Comprehensive Income [Line Items]
Revenues	(4.4)	(4.5)	(8.7)	(9.0)
Operating expenses	(4.4)	(4.5)	(8.7)	(9.0)
Operating income	0.0	0.0	0.0	0.0
Equity in net earnings (losses) of affiliates	(135.6)	(114.6)	(282.5)	(219.3)
Interest expense	22.5	32.5	46.2	63.9
Foreign exchange gain (loss)	0.0	0.0	0.0	0.0
Other income (expense), net	(22.2)	(32.1)	(46.3)	(63.2)
Income before income taxes	(135.3)	(114.2)	(282.6)	(218.6)
Income tax expense (benefit)	0.0	0.0	0.0	0.0
Net income	(135.3)	(114.2)	(282.6)	(218.6)
Less: Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Kansas City Southern and subsidiaries	(135.3)	(114.2)	(282.6)	(218.6)
Other comprehensive income (loss)	(0.8)	1.2	(2.1)	1.3
Comprehensive income attributable to Kansas City Southern and subsidiaries	(136.1)	(113.0)	(284.7)	(217.3)
Condensed Consolidating Financial Information KCS [Member] | Parent [Member]
Condensed Statements of Comprehensive Income [Line Items]
Revenues	0.0	0.0	0.0	0.0
Operating expenses	3.0	1.7	4.1	2.8
Operating income	(3.0)	(1.7)	(4.1)	(2.8)
Equity in net earnings (losses) of affiliates	134.5	113.5	280.6	217.2
Interest expense	(20.1)	(20.5)	(40.7)	(39.4)
Foreign exchange gain (loss)	0.0	0.0	0.0	0.0
Other income (expense), net	22.4	27.7	45.9	52.8
Income before income taxes	133.8	119.0	281.7	227.8
Income tax expense (benefit)	(0.6)	(1.1)	0.7	(0.1)
Net income	134.4	120.1	281.0	227.9
Less: Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Kansas City Southern and subsidiaries	134.4	120.1	281.0	227.9
Other comprehensive income (loss)	(1.8)	(0.6)	(1.0)	(0.7)
Comprehensive income attributable to Kansas City Southern and subsidiaries	132.6	119.5	280.0	227.2
Condensed Consolidating Financial Information KCS [Member] | Guarantor Subsidiaries [Member]
Condensed Statements of Comprehensive Income [Line Items]
Revenues	313.1	260.8	608.3	527.6
Operating expenses	222.3	170.5	439.8	370.4
Operating income	90.8	90.3	168.5	157.2
Equity in net earnings (losses) of affiliates	1.5	1.5	2.8	3.0
Interest expense	(18.2)	(21.0)	(36.9)	(42.6)
Foreign exchange gain (loss)	0.0	0.0	0.0	0.0
Other income (expense), net	(0.3)	(0.2)	0.8	0.1
Income before income taxes	73.8	70.6	135.2	117.7
Income tax expense (benefit)	28.1	27.5	51.7	46.0
Net income	45.7	43.1	83.5	71.7
Less: Net income attributable to noncontrolling interest	0.3	0.4	0.6	0.7
Net income attributable to Kansas City Southern and subsidiaries	45.4	42.7	82.9	71.0
Other comprehensive income (loss)	0.0	0.0	0.0	0.0
Comprehensive income attributable to Kansas City Southern and subsidiaries	45.4	42.7	82.9	71.0
Condensed Consolidating Financial Information KCS [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Statements of Comprehensive Income [Line Items]
Revenues	347.7	312.2	666.3	612.6
Operating expenses	196.2	180.9	380.7	359.2
Operating income	151.5	131.3	285.6	253.4
Equity in net earnings (losses) of affiliates	2.5	2.6	6.0	6.0
Interest expense	(9.2)	(15.4)	(18.3)	(29.9)
Foreign exchange gain (loss)	14.2	(24.0)	61.0	(27.5)
Other income (expense), net	0.0	3.9	0.6	9.8
Income before income taxes	159.0	98.4	334.9	211.8
Income tax expense (benefit)	69.1	26.9	135.2	64.2
Net income	89.9	71.5	199.7	147.6
Less: Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Kansas City Southern and subsidiaries	89.9	71.5	199.7	147.6
Other comprehensive income (loss)	0.8	(1.2)	2.1	(1.3)
Comprehensive income attributable to Kansas City Southern and subsidiaries	90.7	70.3	201.8	146.3
Condensed Consolidating Financial Information KCSR [Member] | Consolidating Adjustments [Member]
Condensed Statements of Comprehensive Income [Line Items]
Revenues	(9.8)	(9.7)	(19.2)	(18.8)
Operating expenses	(9.8)	(9.7)	(19.2)	(18.8)
Operating income	0.0	0.0	0.0	0.0
Equity in net earnings (losses) of affiliates	(134.8)	(114.4)	(281.2)	(218.7)
Interest expense	22.5	32.5	46.2	63.9
Foreign exchange gain (loss)	0.0	0.0	0.0	0.0
Other income (expense), net	(22.2)	(32.1)	(46.3)	(63.2)
Income before income taxes	(134.5)	(114.0)	(281.3)	(218.0)
Income tax expense (benefit)	0.0	0.0	0.0	0.0
Net income	(134.5)	(114.0)	(281.3)	(218.0)
Less: Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Kansas City Southern and subsidiaries	(134.5)	(114.0)	(281.3)	(218.0)
Other comprehensive income (loss)	(0.8)	1.2	(2.1)	1.3
Comprehensive income attributable to Kansas City Southern and subsidiaries	(135.3)	(112.8)	(283.4)	(216.7)
Condensed Consolidating Financial Information KCSR [Member] | Parent [Member]
Condensed Statements of Comprehensive Income [Line Items]
Revenues	0.0	0.0	0.0	0.0
Operating expenses	3.0	1.7	4.1	2.8
Operating income	(3.0)	(1.7)	(4.1)	(2.8)
Equity in net earnings (losses) of affiliates	134.5	113.5	280.6	217.2
Interest expense	(20.1)	(20.5)	(40.7)	(39.4)
Foreign exchange gain (loss)	0.0	0.0	0.0	0.0
Other income (expense), net	22.4	27.7	45.9	52.8
Income before income taxes	133.8	119.0	281.7	227.8
Income tax expense (benefit)	(0.6)	(1.1)	0.7	(0.1)
Net income	134.4	120.1	281.0	227.9
Less: Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Kansas City Southern and subsidiaries	134.4	120.1	281.0	227.9
Other comprehensive income (loss)	(1.8)	(0.6)	(1.0)	(0.7)
Comprehensive income attributable to Kansas City Southern and subsidiaries	132.6	119.5	280.0	227.2
Condensed Consolidating Financial Information KCSR [Member] | KCSR [Member]
Condensed Statements of Comprehensive Income [Line Items]
Revenues	306.5	254.7	595.7	515.3
Operating expenses	217.6	165.9	430.5	361.5
Operating income	88.9	88.8	165.2	153.8
Equity in net earnings (losses) of affiliates	(0.2)	0.2	(0.3)	0.3
Interest expense	(18.2)	(21.0)	(36.9)	(42.6)
Foreign exchange gain (loss)	0.0	0.0	0.0	0.0
Other income (expense), net	(0.3)	(0.2)	0.8	0.1
Income before income taxes	70.2	67.8	128.8	111.6
Income tax expense (benefit)	27.2	26.5	49.8	43.6
Net income	43.0	41.3	79.0	68.0
Less: Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Kansas City Southern and subsidiaries	43.0	41.3	79.0	68.0
Other comprehensive income (loss)	0.0	0.0	0.0	0.0
Comprehensive income attributable to Kansas City Southern and subsidiaries	43.0	41.3	79.0	68.0
Condensed Consolidating Financial Information KCSR [Member] | Guarantor Subsidiaries [Member]
Condensed Statements of Comprehensive Income [Line Items]
Revenues	12.0	11.3	23.1	22.1
Operating expenses	10.1	9.8	19.8	18.7
Operating income	1.9	1.5	3.3	3.4
Equity in net earnings (losses) of affiliates	0.9	1.1	1.8	2.1
Interest expense	0.0	0.0	0.0	0.0
Foreign exchange gain (loss)	0.0	0.0	0.0	0.0
Other income (expense), net	0.0	0.0	0.0	0.0
Income before income taxes	2.8	2.6	5.1	5.5
Income tax expense (benefit)	0.9	1.0	1.9	2.4
Net income	1.9	1.6	3.2	3.1
Less: Net income attributable to noncontrolling interest	0.3	0.4	0.6	0.7
Net income attributable to Kansas City Southern and subsidiaries	1.6	1.2	2.6	2.4
Other comprehensive income (loss)	0.0	0.0	0.0	0.0
Comprehensive income attributable to Kansas City Southern and subsidiaries	1.6	1.2	2.6	2.4
Condensed Consolidating Financial Information KCSR [Member] | Non-Guarantor Subsidiaries [Member]
Condensed Statements of Comprehensive Income [Line Items]
Revenues	347.7	312.2	666.3	612.6
Operating expenses	196.2	180.9	380.7	359.2
Operating income	151.5	131.3	285.6	253.4
Equity in net earnings (losses) of affiliates	2.5	2.6	6.0	6.0
Interest expense	(9.2)	(15.4)	(18.3)	(29.9)
Foreign exchange gain (loss)	14.2	(24.0)	61.0	(27.5)
Other income (expense), net	0.0	3.9	0.6	9.8
Income before income taxes	159.0	98.4	334.9	211.8
Income tax expense (benefit)	69.1	26.9	135.2	64.2
Net income	89.9	71.5	199.7	147.6
Less: Net income attributable to noncontrolling interest	0.0	0.0	0.0	0.0
Net income attributable to Kansas City Southern and subsidiaries	89.9	71.5	199.7	147.6
Other comprehensive income (loss)	0.8	(1.2)	2.1	(1.3)
Comprehensive income attributable to Kansas City Southern and subsidiaries	$ 90.7	$ 70.3	$ 201.8	$ 146.3