OTHER GAINS, NET - Additional information (Details) ¥ in Millions	12 Months Ended
Dec. 31, 2020 CNY (¥)
Shandong Huayu
Gain on disposal of aluminum capacity quota	¥ 539
Fushun Aluminum Co., Ltd
Gain (Loss) on disposal of property, plant and equipment and land use rights	¥ (66)

The gains (losses) on disposals of property, plant and equipment. [Refer: Property, plant and equipment]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 98
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_98_c&doctype=Standard
-URIDate 2020-01-01

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration