The capitalization ratio used to calculate taxes.

No definition available.

Name:	fmx_CapitalizationRatio
Namespace Prefix:	fmx_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent concepts included in income taxes.

+ References

No definition available.

+ Details

Name:	fmx_DisclosureOfIncomeTaxesLineItems
Namespace Prefix:	fmx_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Dividend Rate

+ References

No definition available.

+ Details

Name:	fmx_DividendRate
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tax rate of dividend distribution.

+ References

No definition available.

+ Details

Name:	fmx_DividendTaxOnDistributions
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of excise tax credit on returnable bottles.

+ References

No definition available.

+ Details

Name:	fmx_ExciseTaxCreditOnReturnableBottles
Namespace Prefix:	fmx_
Data Type:	srt-types:perUnitItemType
Balance Type:	na
Period Type:	duration

- Definition

The Mexican excise tax per litre on the the production, sale and import of beverages with added sugar and HFCS for flavoured beverages.

+ References

No definition available.

+ Details

Name:	fmx_ExciseTaxPerLitre
Namespace Prefix:	fmx_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Excise Tax Rate.

+ References

No definition available.

+ Details

Name:	fmx_ExciseTaxRate
Namespace Prefix:	fmx_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

The Minimum alternative income tax rate.

+ References

No definition available.

+ Details

Name:	fmx_MinimumAlternativeIncomeTax
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum assumed income tax rate.

+ References

No definition available.

+ Details

Name:	fmx_MinimumAssumedIncomeTaxRate
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The portion of the municipality sales tax that is credited against income tax payable.

+ References

No definition available.

+ Details

Name:	fmx_MunicipalitySalesTaxPortionCreditedAgainstIncomeTaxPayable
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Nondeductible interest exceeding limit carry forwards, expiration term.

+ References

No definition available.

+ Details

Name:	fmx_NondeductibleInterestExceedingLimitCarryforwardsExpirationTerm
Namespace Prefix:	fmx_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of Capital Gain Tax Rate

+ References

No definition available.

+ Details

Name:	fmx_PercentageOfCapitalGainTaxRate
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of federal production and sales taxes.

+ References

No definition available.

+ Details

Name:	fmx_PercentageOfFederalProductionAndSalesTaxes
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage of tax rate that exceeds EBITDA

+ References

No definition available.

+ Details

Name:	fmx_PercentageOfTaxRateThatExceedsEBITDA
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of withholding taxes on compensations of employees

+ References

No definition available.

+ Details

Name:	fmx_PercentageOfWithholdingTaxesOnCompensationsOfEmployees
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of withholding taxes on salaries of employees.

+ References

No definition available.

+ Details

Name:	fmx_PercentageOfWithholdingTaxesOnSalariesOfEmployees
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The rate of sales tax.

+ References

No definition available.

+ Details

Name:	fmx_SalesTaxRate
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the percentage of selective consumption tax.

+ References

No definition available.

+ Details

Name:	fmx_SelectiveConsumptionTax
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The applicable tax rate applied to dividends received from foreign operations.

+ References

No definition available.

+ Details

Name:	fmx_TaxRateDividendsFromForeignOperations
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of potential net interest expenses at group level that are deductible regardless of the ratio between net interest expenses and Adjusted Taxable Income, under the Mexican corporate tax regime.

+ References

No definition available.

+ Details

Name:	fmx_ThresholdLimitOnDeductibleInterest
Namespace Prefix:	fmx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Value added tax percentage.

+ References

No definition available.

+ Details

Name:	fmx_ValueAddedTaxPercentage
Namespace Prefix:	fmx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The applicable income tax rate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 12
-IssueDate 2020-01-01
-Paragraph 81
-Subparagraph c
-Clause ii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_81_c_ii&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_ApplicableTaxRate
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash flows from income taxes paid or refunded.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2020-01-01
-Paragraph 35
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_35&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_IncomeTaxesPaidRefund
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Tax rate effect on the reconciliation between the average effective tax rate and the applicable tax rate resulting from adjustments for the current tax of prior periods. [Refer: Average effective tax rate; Applicable tax rate; Adjustments for current tax of prior periods]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 12
-IssueDate 2020-01-01
-Paragraph 81
-Subparagraph c
-Clause ii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_81_c_ii&doctype=Standard
-URIDate 2020-01-01

+ Details

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Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_GeographicalAreasAxis=country_MX
Namespace Prefix:
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- Details

Name:	ifrs-full_GeographicalAreasAxis=country_AR
Namespace Prefix:
Data Type:	na
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- Details

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Name:	ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis=fmx_SalesTaxInCityOfBuenosAiresMember
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Data Type:	na
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- Details

Name:	ifrs-full_GeographicalAreasAxis=country_CO
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	fmx_AssesseeAxis=fmx_ColombianResidentIndividualsMember
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Data Type:	na
Balance Type:
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- Details

Name:	fmx_AssesseeAxis=fmx_ForeignNonresidentsIndividualsAndCompaniesMember
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Name:	ifrs-full_GeographicalAreasAxis=country_PA
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fmx_BeveragesAxis=fmx_NoncarbonatedBeveragesMember
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fmx_BeveragesAxis=fmx_CarbonatedBeveragesMember
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Data Type:	na
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- Details

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Data Type:	na
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Taxes (Detail) $ in Millions															1 Months Ended	2 Months Ended	3 Months Ended		4 Months Ended	5 Months Ended	6 Months Ended		10 Months Ended	12 Months Ended
Taxes (Detail) $ in Millions	Feb. 01, 2021	Jan. 01, 2021	Dec. 29, 2020 $ / l	Jan. 01, 2020 USD ($)	Jan. 01, 2020 MXN ($)	Dec. 27, 2019	Nov. 27, 2019	Nov. 18, 2019	Nov. 17, 2019	Jul. 01, 2019	Mar. 01, 2019	Feb. 28, 2019	Jan. 01, 2019	Aug. 31, 2018	Dec. 31, 2018	Jan. 31, 2021	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018	May 31, 2020	Nov. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020 MXN ($)	Dec. 31, 2019 MXN ($)	Dec. 31, 2018 item	Dec. 31, 2017
Disclosure of income taxes [Line Items]
Income tax rate																										30.00%	30.00%	30.00%
Adjustments for previous tax years																										30.30%
Mexico [member]
Disclosure of income taxes [Line Items]
Tax rate, dividends received, as a percent				30.00%	30.00%
Income tax rate																											30.00%	30.00%	30.00%
Excise tax per litre																											1.17
Argentina [member]
Disclosure of income taxes [Line Items]
Income tax rate																													35.00%
Sales Tax Rate																										1.50%
Argentina [member] \| Sales taxes in the province of Buenos Aires [member]
Disclosure of income taxes [Line Items]
Sales Tax Rate																													1.75%
Argentina [member] \| Sales Tax in City of Buenos Aires [member]
Disclosure of income taxes [Line Items]
Sales Tax Rate																										1.50%			1.00%
Colombia [member]
Disclosure of income taxes [Line Items]
Income tax rate																										32.00%	33.00%
Minimum assumed income tax rate																										1.50%	1.50%	3.50%
Capitalization Ratio \| item																												3
Colombia [member] \| Colombian resident individuals [Member]
Disclosure of income taxes [Line Items]
Tax on dividends																	15.00%						15.00%				15.00%
Colombia [member] \| Foreign Nonresidents Individuals And Companies [Member]
Disclosure of income taxes [Line Items]
Tax on dividends															5.00%		7.50%		5.00%				7.50%				7.50%	5.00%
Colombia [member] \| 0-1 year [member]
Disclosure of income taxes [Line Items]
Income tax rate																										31.00%
Colombia [member] \| Later than one year [member]
Disclosure of income taxes [Line Items]
Income tax rate																										30.00%
Panama [member]
Disclosure of income taxes [Line Items]
Excise tax rate							5.0
Selective consumption tax									10.00%
Panama [member] \| NonCarbonated Beverages [Member]
Disclosure of income taxes [Line Items]
Excise tax rate				5.0	5.0
Panama [member] \| Carbonated Beverages [Member]
Disclosure of income taxes [Line Items]
Excise tax rate								7.0
Brazil [member]
Disclosure of income taxes [Line Items]
Income tax recoveries \| $																										$ 2,523,000,000	$ 4,223,000,000
Excise tax rate	8													20.0	4.0	4.0	10.0	8.0	4.0	4.0	8.0	12.0
Percentage of federal production and sales taxes																										15.90%
Chile [member]
Disclosure of income taxes [Line Items]
Income tax rate																										27.00%
Nicaragua [member]
Disclosure of income taxes [Line Items]
Excise tax rate												9.0
Minimum alternative tax rate												1.00%
Uruguay [member]
Disclosure of income taxes [Line Items]
Excise tax credit \| $ / l			1.15
Changes in tax rates or tax laws enacted or announced [member] \| Mexico [member]
Disclosure of income taxes [Line Items]
Income tax rate				30.00%	30.00%
Threshold limit on deductible interest				$ 1	$ 20,000,000
Expiration term of nondeductible interest exceeding limit				10 years	10 years
Excise tax per litre				1.2616	1.2616
Changes in tax rates or tax laws enacted or announced [member] \| Mexico [member] \| Carbonated Beverages [Member]
Disclosure of income taxes [Line Items]
Excise tax rate				7.0	7.0																						5.0
Changes in tax rates or tax laws enacted or announced [member] \| Mexico [member] \| Caffeinated, Carbonated Beverages [Member]
Disclosure of income taxes [Line Items]
Excise tax rate				25	25
Changes in tax rates or tax laws enacted or announced [member] \| Argentina [member]
Disclosure of income taxes [Line Items]
Income tax rate				30.00%	30.00%																					25.00%	30.00%	30.00%
Tax on dividends				7.00%	7.00%										7.00%		7.00%		7.00%				7.00%			13.00%	7.00%	7.00%
Changes in tax rates or tax laws enacted or announced [member] \| Argentina [member] \| Sales taxes in the province of Buenos Aires [member]
Disclosure of income taxes [Line Items]
Sales Tax Rate																												1.50%
Changes in tax rates or tax laws enacted or announced [member] \| Argentina [member] \| Sales Tax in City of Buenos Aires [member]
Disclosure of income taxes [Line Items]
Sales Tax Rate																								0.00%	0.50%	1.00%	1.50%	2.00%
Changes in tax rates or tax laws enacted or announced [member] \| Colombia [member]
Disclosure of income taxes [Line Items]
Minimum assumed income tax rate																									0.00%	0.50%
Municipality sales tax, portion credited against income tax payable, as a percent																										100.00%	50.00%
Tax rate of dividend distribution													7.50%
Changes in tax rates or tax laws enacted or announced [member] \| Colombia [member] \| Colombian resident individuals [Member]
Disclosure of income taxes [Line Items]
Tax on dividends				10.00%	10.00%
Changes in tax rates or tax laws enacted or announced [member] \| Colombia [member] \| Foreign Nonresidents Individuals And Companies [Member]
Disclosure of income taxes [Line Items]
Municipality sales tax, portion credited against income tax payable, as a percent						100.00%
Tax on dividends				10.00%	10.00%								7.50%
Changes in tax rates or tax laws enacted or announced [member] \| Panama [member]
Disclosure of income taxes [Line Items]
Selective consumption tax								10.00%
Changes in tax rates or tax laws enacted or announced [member] \| Costa Rica [member]
Disclosure of income taxes [Line Items]
Value-added tax										13.00%
Percentage of capital gains										15.00%
Percentage of withholding taxes on salaries of employees										25.00%
Percentage of withholding taxes on compensations of employees										20.00%
Percentage of tax rate that exceeds EBITDA										20.00%
Changes in tax rates or tax laws enacted or announced [member] \| Nicaragua [member]
Disclosure of income taxes [Line Items]
Excise tax rate		15.0																					11.0			13.0
Minimum alternative tax rate											3.00%