Other Assets and Other Financial Assets - Fair value (Detail) - MXN ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Other Assets And Other Financial Assets [line items]
Non-current accounts receivables	$ 983	$ 938
Fair value [member]
Disclosure Of Other Assets And Other Financial Assets [line items]
Non-current accounts receivables	$ 699	$ 724

The amount of non-current trade receivables and non-current other receivables. [Refer: Non-current trade receivables; Other non-current receivables]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 54
-Subparagraph h
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_54_h&doctype=Standard
-URIDate 2020-01-01

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 78
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_78_b&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_NoncurrentReceivables
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant