Basis of Presentation (Details) $ in Millions	Jan. 01, 2019 USD ($)
Accounting Policies [Abstract]
Additional right-of-use lease assets recognized as a result of adoption of ASU 2016-02	$ 175.2
Additional lease liabilities recognized as a result of adoption of ASU 2016-02	$ 175.2

Additional amount recognized of present value of lessee’s discounted obligation for lease payments from operating and finance leases.

No definition available.

Name:	ksu_OperatingandFinanceLeaseAdditionalLiability
Namespace Prefix:	ksu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant