Marketable Securities and Other Short-term Investments - Additional Information (Detail) - MXN ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of information about marketable securities and other short term investments [line items]
Dividends received	$ 2,385,559	$ 5,740,092	$ 1,645,712
Investments accounted for using equity method Koninklijke KPN [member]
Disclosure of information about marketable securities and other short term investments [line items]
Other short-term investments	12,438,019	13,393,646
Investment pre-tax gain		11,988,038
Changes in fair value of investment	622,424	(6,673,731)
Dividends received	2,370,559	5,740,092	$ 1,645,712
Market securities and other short term investments [member] \| Investments accounted for using equity method Koninklijke KPN [member]
Disclosure of information about marketable securities and other short term investments [line items]
Available for sale investment	46,682,657	41,463,511
Other short-term investments	$ 12,438,019	$ 13,393,646

Line items represents information about marketable securities and other short term investments.

No definition available.

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- Definition

Other short term investments2.

+ References

No definition available.

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- Definition

The amount of financial assets that are measured at fair value and for which gains (losses) are recognised in profit or loss. A financial asset shall be measured at fair value through profit or loss unless it is measured at amortised cost or at fair value through other comprehensive income. A gain (loss) on a financial asset measured at fair value shall be recognised in profit or loss unless it is part of a hedging relationship, it is an investment in an equity instrument for which the entity has elected to present gains and losses in other comprehensive income or it is a financial asset measured at fair value through other comprehensive income. [Refer: At fair value [member]; Financial assets]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2017-01-01
-Paragraph 8
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-01&anchor=para_8_a&doctype=Standard
-URIDate 2017-03-09

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- Definition

The amount of non-derivative financial assets that are designated as available for sale or are not classified as (a) loans and receivables; (b) held-to-maturity investments; or (c) financial assets at fair value through profit or loss. [Refer: Derivative financial assets; Financial assets at fair value through profit or loss; Held-to-maturity investments]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IFRS
-Number 7
-IssueDate 2017-01-01
-Paragraph 8
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_8_d&doctype=Standard&book=B
-URIDate 2017-03-09

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- Definition

The gains (losses) from changes in the fair value of investment property. [Refer: Investment property]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 40
-IssueDate 2017-01-01
-Paragraph 76
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=40&date=2017-03-01&anchor=para_76_d&doctype=Standard
-URIDate 2017-03-09

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- Definition

The amount of dividends recognised as income. Dividends are distributions of profits to holders of equity investments in proportion to their holdings of a particular class of capital.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IAS
-Number 18
-IssueDate 2017-01-01
-Paragraph 35
-Subparagraph b
-Clause v
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=18&date=2017-03-02&anchor=para_35_b_v&doctype=Standard&book=B
-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_112_c&doctype=Standard
-URIDate 2017-03-09

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