Financial Assets and Liabilities - Summary of Analysis of Gains (Losses) on Derivative Financial Instruments (Detail) - PHP (₱) ₱ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure Of Hedge Accounting [Abstract]
Gains on derivative financial instruments (Note 4)	₱ 724	₱ 1,539	₱ 781
Hedge costs	(191)	(543)	(361)
Net gains on derivative financial instruments (Note 5)	₱ 533	₱ 996	₱ 420

The gain (loss) recognised on designation of a financial instrument, or a proportion of it, as measured at fair value through profit or loss, because a credit derivative is used to manage the credit risk of that financial instrument. [Refer: Credit risk [member]; Derivatives [member]; Financial instruments, class [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Effective 2018-01-01
-Name IFRS
-Number 7
-IssueDate 2017-01-01
-Paragraph 24G
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-01&anchor=para_24G_b&doctype=Standard
-URIDate 2017-03-09

Name:	ifrs-full_GainLossOnDesignationOfFinancialInstrumentAsMeasuredAtFairValueThroughProfitOrLossBecauseCreditDerivativeIsUsedToManageCreditRisk
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration