PLEDGE OF ASSETS (Details) - CNY (¥) ¥ in Thousands	Dec. 31, 2020	Dec. 31, 2019
PLEDGE OF ASSETS
Property, plant and equipment	¥ 5,191,185	¥ 4,946,338
Right-of-use assets	1,232,491	373,048
Intangible assets	960	757,269
Notes receivable pledged	1,499,260	667,190
Investments in associates	395,610	538,787
Assets pledged as security	8,319,506	7,282,632
Current portion of long-term loans and borrowings secured by contractual right to charge users for electricity generated in the future	912,000	1,209,000
Non-current portion of long-term loans and borrowings secured by contractual right to charge users for electricity generated in the future	¥ 5,976,000	¥ 10,265,000

The amount of assets pledged as security for liabilities.

No definition available.

Name:	ach_AssetsPledgedAsSecurity
Namespace Prefix:	ach_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of contractual right to charge users for electricity generated in the future, pledged as security for current portion of long term loans.

+ References

No definition available.

+ Details

Name:	ach_ContractualRightToChargeUsersForElectricityGeneratedInFuturePledgedAsSecurityForCurrentPortionOfLongTermLoans
Namespace Prefix:	ach_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of contractual right to charge users for electricity generated in the future, pledged as security for non-current portion of long term loans.

+ References

No definition available.

+ Details

Name:	ach_ContractualRightToChargeUsersForElectricityGeneratedInFuturePledgedAsSecurityForNonCurrentPortionOfLongTermLoans
Namespace Prefix:	ach_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	ach_DisclosureOfAssetsPledgedAbstract
Namespace Prefix:	ach_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of investments accounted for using equity method pledged as security for liabilities.

+ References

No definition available.

+ Details

Name:	ach_InvestmentsAccountedForUsingEquityMethodPledgedAsSecurityForLiabilities
Namespace Prefix:	ach_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of notes receivables pledged as security for liabilities.

+ References

No definition available.

+ Details

Name:	ach_NotesReceivablesPledgedAsSecurity
Namespace Prefix:	ach_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of right of use assets pledged as security for liabilities.

+ References

No definition available.

+ Details

Name:	ach_RightOfUseAssetsPledgedAsSecurity
Namespace Prefix:	ach_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of intangible assets pledged as security for liabilities. [Refer: Intangible assets other than goodwill]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 38
-IssueDate 2020-01-01
-Paragraph 122
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_122_d&doctype=Standard
-URIDate 2020-01-01

+ Details

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

- Definition

The amount of property, plant and equipment pledged as security for liabilities. [Refer: Property, plant and equipment]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 16
-IssueDate 2020-01-01
-Paragraph 74
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=16&code=ifrs-tx-2020-en-r&anchor=para_74_a&doctype=Standard
-URIDate 2020-01-01

+ Details

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