Income Taxes - Summary of the Balances of the Deferred tax Assets and Liabilities in Statement of Financial Position (Detail) - MXN ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disclosure of Deferred Tax Assets And Liabilities [line items]
Asset	$ 11,567	$ 14,817
Liability	(14,900)	(15,801)
Net	(3,333)	(984)
Country of domicile [member]
Disclosure of Deferred Tax Assets And Liabilities [line items]
Asset	3,079	3,212
Liability	(7,493)	(7,190)
Net	(4,414)	(3,978)
Foreign countries [member]
Disclosure of Deferred Tax Assets And Liabilities [line items]
Asset	8,488	11,605
Liability	(7,407)	(8,611)
Net	$ 1,081	$ 2,994

Disclosure of Deferred Tax Assets And Liabilities [line items]

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- Definition

The amount of deferred tax liabilities or assets. [Refer: Deferred tax liabilities; Deferred tax assets]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 12
-IssueDate 2018-01-01
-Paragraph 81
-Subparagraph g
-Clause i
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=12&date=2018-03-01&anchor=para_81_g_i&doctype=Standard
-URIDate 2018-03-16

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- Definition

The amount of deferred tax assets net of deferred tax liabilities, when the absolute amount of deferred tax assets is greater than the absolute amount of deferred tax liabilities. [Refer: Deferred tax assets; Deferred tax liabilities]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 12
-IssueDate 2018-01-01
-Paragraph 81
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-Clause i
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=12&date=2018-03-01&anchor=para_81_g_i&doctype=Standard
-URIDate 2018-03-16

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- Definition

The amount of deferred tax liabilities net of deferred tax assets, when the absolute amount of deferred tax liabilities is greater than the absolute amount of deferred tax assets. [Refer: Deferred tax assets; Deferred tax liabilities]

+ References

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