Other Gains - Summary of Other Gains (Detail) - CNY (¥) ¥ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Analysis of income and expense [abstract]
Compensation income	¥ 758	¥ 915	¥ 1,184
Additional deduction of input value-added tax	2,813	667
Others	2,031	2,447	1,722
Other gains	¥ 5,602	¥ 4,029	¥ 2,906

The gains (losses) that the entity does not separately disclose in the same statement or note.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 102
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_102&doctype=Standard
-URIDate 2020-01-01

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 103
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_103&doctype=Standard
-URIDate 2020-01-01

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