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Financial Instruments - Net Effect of Expired Contracts That Did Not Meet Hedging Criteria (Details) - Derivative Contract Not Met Hedging Criteria - Market value gain on financial instruments - MXN ($) $ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Cross-currency swaps |  |
Disclosure of detailed information about hedges [line items] |  |
Net effects of expired contracts | $ 212 | $ 293
Embedded Derivative |  |
Disclosure of detailed information about hedges [line items] |  |
Net effects of expired contracts |  | $ (4)

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- Definition The gain (loss) attributable to expired derivative contracts recognized in profit or loss during the period. + References No definition available. + Details
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Balance Type: | credit
Period Type: | duration

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- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table. + References No definition available. + Details
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Data Type: | xbrli:stringItemType
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Period Type: | duration

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- Details
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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
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- Details
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- Details
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