XML 164 R149.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Financial Instruments - Disclosure of Net Effect of Expired Contracts Did Not Meet Hedging Criteria for Accounting Purposes (Detail) - MXN ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2015
Derivative financial instruments did not meet hedging criteria [member] | Cross-currency swaps [member] | Market value gain on financial instruments [member] |  |
Disclosure of detailed information about hedges [line items] |  |
Net effects derivative contracts hedging criteria | $ (438) | $ 204

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_DisclosureOfHedgeAccountingLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The gains resulting from change in the fair value of derivatives recognised in profit or loss. [Refer: Derivatives [member]] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 85 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_85&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_GainsOnChangeInFairValueOfDerivatives
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | ifrs-full_ClassesOfFinancialAssetsAxis=fmx_DerivativeContractNotMetHedgingCriteriaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=fmx_UnrealisedGainLossesOnDerivativeFinancialInstrumentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |