Other Operating Expenses - Summary of Other Operating Expenses (Parenthetical) (Detail) - CNY (¥) ¥ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of other operating expenses [line items]
Auditor's remuneration for audit service	¥ 109	¥ 111	¥ 108
United States [member] \| Attestation under s404 of Sarbanes-Oxley Act 2002 [member]
Disclosure of other operating expenses [line items]
Auditor's remuneration for audit service	¥ 22	¥ 22	¥ 22

The amount of fees paid or payable to the entity's auditors for auditing services.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 112
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_AuditorsRemunerationForAuditServices
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration