Inventories and Supplies - Summary of Cost of Inventories and Supplies Recognized as Expense (Detail) - PHP (₱) ₱ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Classes Of Inventories [Abstract]
Cost of sales	₱ 7,375	₱ 8,882	₱ 9,528
Repairs and maintenance	850	613	823
Inventories and supplies (Note 18)	847	934	471
Selling and promotions	9	3	138
Inventories and supplies recognized as expense	₱ 9,081	₱ 10,432	₱ 10,960

The amount of expense recognised related to the write-down of inventories to net realisable value. [Refer: Inventories]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 2
-IssueDate 2021-01-01
-Paragraph 36
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=2&code=ifrs-tx-2021-en-r&anchor=para_36_e&doctype=Standard
-URIDate 2021-03-24

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 98
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_98_a&doctype=Standard
-URIDate 2021-03-24

Name:	ifrs-full_InventoryWritedown2011
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration