Other Liabilities, Provisions, Contingencies and Commitments - Schedule of Future Minimum Lease Payments (Detail) - MXN ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of financial liabilities [line items]
Minimum payments	$ 100	$ 132
Present value of minimum lease payments	92	116
Minimum Payments [member]
Disclosure of financial liabilities [line items]
Less amount representing finance charges	8	16
Present value of minimum lease payments	92	116
Less than 1 year [member]
Disclosure of financial liabilities [line items]
Minimum payments	38	41
Present value of minimum lease payments	33	34
1-5 years [Member]
Disclosure of financial liabilities [line items]
Minimum payments	62	91
Present value of minimum lease payments	$ 59	$ 82

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

No definition available.

+ Details

Name:	ifrs-full_DisclosureOfFinancialLiabilitiesLineItems
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount representing the difference between the future minimum finance lease payments and their present value. Minimum lease payments are payments over the lease term that the lessee is or can be required to make, excluding contingent rent, costs for services and taxes to be paid by, and reimbursed to, the lessor, together with: (a) for a lessee, any amounts guaranteed by the lessee or by a party related to the lessee; or (b) for a lessor, any residual value guaranteed to the lessor by: (i) the lessee; (ii) a party related to the lessee; or (iii) a third party unrelated to the lessor that is financially capable of discharging the obligations under the guarantee.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2019-01-01
-Name IAS
-Number 17
-IssueDate 2018-01-01
-Paragraph 31
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=17&date=2018-03-02&anchor=para_31_b&doctype=Standard&book=b
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_FutureFinanceChargeOnFinanceLease
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of payments over the finance lease term that the lessee is or can be required to make, excluding contingent rent, costs for services and taxes to be paid by, and reimbursed to, the lessor, together with any amounts guaranteed by the lessee or by a party related to the lessee.

+ References

+ Details

Name:	ifrs-full_MinimumFinanceLeasePaymentsPayable
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The present value of minimum finance lease payments payable. [Refer: Minimum finance lease payments payable]

+ References

+ Details

Name:	ifrs-full_MinimumFinanceLeasePaymentsPayableAtPresentValue
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	ifrs-full_ArrangementsInvolvingLegalFormOfLeaseAxis=fmx_MinimumPaymentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MaturityAxis=ifrs-full_NotLaterThanOneYearMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_MaturityAxis=ifrs-full_LaterThanOneYearAndNotLaterThanFiveYearsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: