Cover Page - USD ($) $ in Millions	12 Months Ended
Cover Page - USD ($) $ in Millions	Dec. 31, 2021	Jan. 31, 2022	Jun. 30, 2021
Document Information [Line Items]
Amendment Flag	true
Entity Central Index Key	0000054480
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
No Trading Symbol Flag	true
Document Type	10-K/A
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	1-4717
Entity Registrant Name	KANSAS CITY SOUTHERN
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	87-3883291
Entity Address, Address Line One	427 West 12th Street
Entity Address, City or Town	Kansas City
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	64105
City Area Code	816
Local Phone Number	983.1303
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Entity Public Float			$ 25,630
Entity Common Stock, Shares Outstanding		100
Documents Incorporated by Reference	None.
Amendment Description	On December 14, 2021, the New York Stock Exchange LLC (the “NYSE”) filed Form 25s with the Securities and Exchange Commission (the “SEC”) to delist the registrant’s common stock and preferred stock from the NYSE and to deregister the common stock and preferred stock under Section 12(b) of the Act. On December 27, 2021, the registrant filed with the SEC a Form 15 with respect to the common stock and preferred stock, requesting that the duty of the registrant to file reports under Section 13 of the Act with respect to such securities be terminated and the duty of the registrant to file reports under Section 15(d) of the Act with respect to such securities be suspended. This Amendment No. 1 on Form 10-K/A amends the Annual Report on Form 10-K of Kansas City Southern (the “Company”) for the fiscal year ended December 31, 2021 (“2021 Form 10-K”), originally filed with the U.S. Securities and Exchange Commission (the “SEC”) on February 1, 2022.In reliance upon and as permitted by Instruction G(3) to Form 10-K, the Company is filing this Amendment No. 1 on Form 10-K/A to include in the 2021 Form 10-K the Part III information not previously included in the 2021 Form 10-K. This Amendment No. 1 on Form 10-K/A consists solely of the preceding cover page, this explanatory note, the information required by Part III, Items 10, 11, 12, 13, and 14 of Form 10-K, a signature page and certifications required to be filed as exhibits. We are amending Part IV solely to add those certifications. No attempt has been made in this Amendment No. 1 on Form 10-K/A to modify or update the other disclosures presented in the 2021 Form 10-K. This Amendment No. 1 on Form 10-K/A does not reflect events occurring after the filing of the 2021 Form 10-K. Accordingly, this Amendment No. 1 on Form 10-K/A should be read in conjunction with the 2021 Form 10-K and the Company’s other filings with the SEC. In this Amendment No. 1 on Form 10-K/A, we also refer to Kansas City Southern as “KCS” or the “Company.” Unless otherwise indicated herein, all page references contained in this Amendment No. 1 on Form 10-K/A are to the pages of this Amendment No. 1 on Form 10-K/A, and not to the 2021 Form 10-K.
Auditor Name	PricewaterhouseCoopers LLP
Auditor Firm ID	238
Auditor Location	Kansas City, Missouri
$25 Par Preferred Stock [Member]
Document Information [Line Items]
Title of 12(b) Security	Preferred Stock, Par Value $25 Per Share, 4%, Noncumulative
$.01 Par Common Stock [Member]
Document Information [Line Items]
Title of 12(b) Security	Common Stock, $.01 Per Share Par Value

KANSAS CITY SOUTHERN 10-K/A