XML 188 R128.htm IDEA: XBRL DOCUMENT
v3.20.1

Employee Benefits - Summary of Trust Assets (Detail) - Level 1 [member] | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Variable return: |  |
Trust assets fixed and variable return percentage | 100.00% | 100.00%
Traded Securities [member] |  |
Fixed return: |  |
Trust assets fixed return percentage | 9.00% | 19.00%
Bank instruments [member] |  |
Fixed return: |  |
Trust assets fixed return percentage | 23.00% | 6.00%
Federal government instruments of the respective countries [member] |  |
Fixed return: |  |
Trust assets fixed return percentage | 33.00% | 60.00%
Publicly traded shares [member] |  |
Variable return: |  |
Trust assets variable return percentage | 35.00% | 15.00%

X
- Definition Fixed return. + References No definition available. + Details
Name: | fmx_FixedReturnAbstract
Namespace Prefix: | fmx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Trust assets fixed and variable return percentage. + References No definition available. + Details
Name: | fmx_TrustAssetsFixedAndVariableReturnPercentage
Namespace Prefix: | fmx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Trust assets fixed return percentage. + References No definition available. + Details
Name: | fmx_TrustAssetsFixedReturnPercentage
Namespace Prefix: | fmx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Trust assets variable return percentage. + References No definition available. + Details
Name: | fmx_TrustAssetsVariableReturnPercentage
Namespace Prefix: | fmx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Variable return. + References No definition available. + Details
Name: | fmx_VariableReturnAbstract
Namespace Prefix: | fmx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_LevelsOfFairValueHierarchyAxis=ifrs-full_Level1OfFairValueHierarchyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialInstrumentsAxis=fmx_TradedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialInstrumentsAxis=fmx_BankInstrumentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialInstrumentsAxis=fmx_FederalGovernmentInstrumentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfFinancialInstrumentsAxis=fmx_PubliclyTradedSharesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |