Condensed Consolidating Balance Sheets (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Assets:
Current assets	$ 711.4	$ 648.0
Investments	36.2	32.9
Investments in consolidated subsidiaries	0.0	0.0
Property and equipment (including concession assets), net	8,247.3	8,069.7
Other assets	72.7	66.9
Total assets	9,067.6	8,817.5
Liabilities and equity:
Current liabilities	821.3	744.4
Long-term debt	2,243.6	2,271.5
Deferred income taxes	1,385.4	1,289.3
Other liabilities	109.5	107.8
Stockholders' equity	4,192.6	4,089.9
Noncontrolling interest	315.2	314.6
Total liabilities and equity	9,067.6	8,817.5
Condensed Consolidating Financial Information KCS [Member] | Consolidating Adjustments [Member]
Assets:
Current assets	(6.9)	(9.5)
Investments	0.0	0.0
Investments in consolidated subsidiaries	(4,272.8)	(3,991.4)
Property and equipment (including concession assets), net	(2.7)	(2.7)
Other assets	(2,244.2)	(2,244.2)
Total assets	(6,526.6)	(6,247.8)
Liabilities and equity:
Current liabilities	(8.3)	(10.9)
Long-term debt	(2,244.2)	(2,244.2)
Deferred income taxes	(0.9)	(0.9)
Other liabilities	0.0	0.0
Stockholders' equity	(4,273.2)	(3,991.8)
Noncontrolling interest	0.0	0.0
Total liabilities and equity	(6,526.6)	(6,247.8)
Condensed Consolidating Financial Information KCS [Member] | Parent [Member]
Assets:
Current assets	2.6	0.9
Investments	0.0	0.0
Investments in consolidated subsidiaries	3,776.9	3,497.7
Property and equipment (including concession assets), net	0.0	0.0
Other assets	2,015.3	2,015.5
Total assets	5,794.8	5,514.1
Liabilities and equity:
Current liabilities	(204.2)	(501.3)
Long-term debt	1,762.9	1,883.1
Deferred income taxes	24.0	26.9
Other liabilities	8.0	4.0
Stockholders' equity	4,204.1	4,101.4
Noncontrolling interest	0.0	0.0
Total liabilities and equity	5,794.8	5,514.1
Condensed Consolidating Financial Information KCS [Member] | Guarantor Subsidiaries [Member]
Assets:
Current assets	197.4	275.4
Investments	3.9	3.9
Investments in consolidated subsidiaries	495.9	493.7
Property and equipment (including concession assets), net	4,343.4	4,203.6
Other assets	47.8	43.0
Total assets	5,088.4	5,019.6
Liabilities and equity:
Current liabilities	822.2	1,004.0
Long-term debt	1,477.3	1,357.7
Deferred income taxes	1,123.5	1,075.3
Other liabilities	84.3	86.3
Stockholders' equity	1,265.9	1,181.7
Noncontrolling interest	315.2	314.6
Total liabilities and equity	5,088.4	5,019.6
Condensed Consolidating Financial Information KCS [Member] | Non-Guarantor Subsidiaries [Member]
Assets:
Current assets	518.3	381.2
Investments	32.3	29.0
Investments in consolidated subsidiaries	0.0	0.0
Property and equipment (including concession assets), net	3,906.6	3,868.8
Other assets	253.8	252.6
Total assets	4,711.0	4,531.6
Liabilities and equity:
Current liabilities	211.6	252.6
Long-term debt	1,247.6	1,274.9
Deferred income taxes	238.8	188.0
Other liabilities	17.2	17.5
Stockholders' equity	2,995.8	2,798.6
Noncontrolling interest	0.0	0.0
Total liabilities and equity	4,711.0	4,531.6
Condensed Consolidating Financial Information KCSR [Member] | Consolidating Adjustments [Member]
Assets:
Current assets	(6.9)	(10.5)
Investments	0.0	0.0
Investments in consolidated subsidiaries	(4,259.9)	(3,979.6)
Property and equipment (including concession assets), net	(2.7)	(2.7)
Other assets	(2,244.2)	(2,244.2)
Total assets	(6,513.7)	(6,237.0)
Liabilities and equity:
Current liabilities	(8.3)	(11.8)
Long-term debt	(2,244.2)	(2,244.3)
Deferred income taxes	(0.9)	(0.9)
Other liabilities	0.0	0.0
Stockholders' equity	(4,260.3)	(3,980.0)
Noncontrolling interest	0.0	0.0
Total liabilities and equity	(6,513.7)	(6,237.0)
Condensed Consolidating Financial Information KCSR [Member] | Parent [Member]
Assets:
Current assets	2.6	0.9
Investments	0.0	0.0
Investments in consolidated subsidiaries	3,776.9	3,497.7
Property and equipment (including concession assets), net	0.0	0.0
Other assets	2,015.3	2,015.5
Total assets	5,794.8	5,514.1
Liabilities and equity:
Current liabilities	(204.2)	(501.3)
Long-term debt	1,762.9	1,883.1
Deferred income taxes	24.0	26.9
Other liabilities	8.0	4.0
Stockholders' equity	4,204.1	4,101.4
Noncontrolling interest	0.0	0.0
Total liabilities and equity	5,794.8	5,514.1
Condensed Consolidating Financial Information KCSR [Member] | KCSR [Member]
Assets:
Current assets	188.5	271.8
Investments	3.9	3.9
Investments in consolidated subsidiaries	(10.9)	(9.8)
Property and equipment (including concession assets), net	4,168.1	4,024.5
Other assets	47.8	43.0
Total assets	4,397.4	4,333.4
Liabilities and equity:
Current liabilities	733.0	913.2
Long-term debt	1,477.3	1,357.7
Deferred income taxes	984.0	937.7
Other liabilities	84.2	86.2
Stockholders' equity	1,118.9	1,038.6
Noncontrolling interest	0.0	0.0
Total liabilities and equity	4,397.4	4,333.4
Condensed Consolidating Financial Information KCSR [Member] | Guarantor Subsidiaries [Member]
Assets:
Current assets	8.9	4.6
Investments	0.0	0.0
Investments in consolidated subsidiaries	493.9	491.7
Property and equipment (including concession assets), net	175.3	179.1
Other assets	0.0	0.0
Total assets	678.1	675.4
Liabilities and equity:
Current liabilities	89.2	91.7
Long-term debt	0.0	0.1
Deferred income taxes	139.5	137.6
Other liabilities	0.1	0.1
Stockholders' equity	134.1	131.3
Noncontrolling interest	315.2	314.6
Total liabilities and equity	678.1	675.4
Condensed Consolidating Financial Information KCSR [Member] | Non-Guarantor Subsidiaries [Member]
Assets:
Current assets	518.3	381.2
Investments	32.3	29.0
Investments in consolidated subsidiaries	0.0	0.0
Property and equipment (including concession assets), net	3,906.6	3,868.8
Other assets	253.8	252.6
Total assets	4,711.0	4,531.6
Liabilities and equity:
Current liabilities	211.6	252.6
Long-term debt	1,247.6	1,274.9
Deferred income taxes	238.8	188.0
Other liabilities	17.2	17.5
Stockholders' equity	2,995.8	2,798.6
Noncontrolling interest	0.0	0.0
Total liabilities and equity	$ 4,711.0	$ 4,531.6