Other non-current assets - Additional Information (Detail) - CNY (¥) ¥ in Millions	Dec. 31, 2020	Dec. 31, 2019
Miscellaneous non-current assets [abstract]
Long-term prepaid expenses	¥ 4,445	¥ 4,662
Certificates of deposit	¥ 15,000	¥ 5,130

The amount of non-current prepayments. [Refer: Prepayments]

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 78
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_78_b&doctype=Standard
-URIDate 2020-01-01

Name:	ifrs-full_NoncurrentPrepayments
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant