Refundable Mexican Value Added Tax (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
KCSM [Member] \| Long-Term Asset [Member]
Refundable Mexican Value Added Tax [Line Items]
Refundable Mexican value added tax	$ 142.6	$ 103.1

Carrying amount as of the balance sheet date of value added taxes due either from customers arising from sales on credit terms, or as previously overpaid to tax authorities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Name:	us-gaap_ValueAddedTaxReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant