Income tax incurred and deferred: Temporal differences (Details) - MXN ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2014
Income tax incurred and deferred:
Undistributed utilities	$ 3,200,543	$ 3,424,951
Tax rate	30.00%	30.00%	30.00%	30.00%
Deferred income tax liabilities unrecognized with the previous temporary differences	$ 960,163	$ 1,027,485

The aggregate amount of temporary differences associated with investments in subsidiaries, branches and associates and interests in joint arrangements, for which deferred tax liabilities have not been recognised as a result of satisfying both of the following conditions: (a) the parent, investor, joint venturer or joint operator is able to control the timing of the reversal of the temporary difference; and (b) it is probable that the temporary difference will not reverse in the foreseeable future. [Refer: Associates [member]; Subsidiaries [member]; Temporary differences [member]; Investments in subsidiaries]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 12
-IssueDate 2020-01-01
-Paragraph 81
-Subparagraph f
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=12&code=ifrs-tx-2020-en-r&anchor=para_81_f&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_TemporaryDifferencesAssociatedWithInvestmentsInSubsidiariesBranchesAndAssociatesAndInterestsInJointVentures
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant