XML 143 R127.htm IDEA: XBRL DOCUMENT
v3.19.1

Employee Benefits - Additional Information (Detail) | 12 Months Ended
--- | ---
Dec. 31, 2018
Mexican subsidiaries [member] |
Disclosure of defined benefit plans [line items] |
Plan asset investment for related parties, percentage | 10.00%
Discount rates [member] |
Disclosure of defined benefit plans [line items] |
Impact on absolute terms of variation in the assumptions on net defined benefit liability | 1.00%
Bottom of range [member] | Mexican Federal Government instruments [member] |
Disclosure of defined benefit plans [line items] |
Fund assets, percentage | 30.00%

X
- Definition Percentage of fund assets. + References No definition available. + Details
Name: | fmx_PercentageOfFundAssets
Namespace Prefix: | fmx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of plan asset investment for related parties. + References No definition available. + Details
Name: | fmx_PercentageOfPlanAssetInvestmentForRelatedParties
Namespace Prefix: | fmx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition 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. + References No definition available. + Details
Name: | ifrs-full_DisclosureOfDefinedBenefitPlansLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The reasonably possible percentage of the increase in the actuarial assumption used to determine the present value of defined benefit obligation. [Refer: Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2018-01-01 -Paragraph 145 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_145_a&doctype=Standard -URIDate 2018-03-16 + Details
Name: | ifrs-full_PercentageOfReasonablyPossibleIncreaseInActuarialAssumption
Namespace Prefix: | ifrs-full_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | ifrs-full_CategoriesOfRelatedPartiesAxis=ifrs-full_SubsidiariesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ActuarialAssumptionsAxis=ifrs-full_ActuarialAssumptionOfDiscountRatesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ContinuingInvolvementInDerecognisedFinancialAssetsByTypeOfInstrumentAxis=fmx_MexicanFederalGovernmentInstrumentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |