LEASE - Amount recognized in profit and loss in relation to leases (Details) - CNY (¥) ¥ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
LEASE
Interest on lease liabilities	¥ 466,796
Depreciation charge of right-of-use assets	767,553	¥ 1,075,825	¥ (108,152)
Expense relating to short-term leases	214,204
Expense relating to leases of low-value assets	39,130
Total amount recognized in profit or loss	¥ 1,487,683

Represents the total amount of lease expenses recognised in profit and loss accounts.

No definition available.

Name:	ach_TotalLeaseExpensesRecognisedInProfitAndLoss
Namespace Prefix:	ach_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of depreciation of right-of-use assets. [Refer: Depreciation and amortisation expense; Right-of-use assets]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2020-01-01
-Paragraph 53
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2020-en-r&anchor=para_53_a&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_DepreciationRightofuseAssets
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of the expense relating to leases of low-value assets accounted for applying paragraph 6 of IFRS 16. This expense shall not include the expense relating to short-term leases of low-value assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2020-01-01
-Paragraph 53
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2020-en-r&anchor=para_53_d&doctype=Standard
-URIDate 2020-01-01

+ Details

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

- Definition

The amount of the expense relating to short-term leases accounted for applying paragraph 6 of IFRS 16. This expense need not include the expense relating to leases with a lease term of one month or less. Short-term lease is a lease that, at the commencement date, has a lease term of 12 months or less. A lease that contains a purchase option is not a short-term lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2020-01-01
-Paragraph 53
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2020-en-r&anchor=para_53_c&doctype=Standard
-URIDate 2020-01-01

+ Details

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

- Definition

The amount of interest expense on lease liabilities. [Refer: Lease liabilities]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2020-01-01
-Paragraph 53
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2020-en-r&anchor=para_53_b&doctype=Standard
-URIDate 2020-01-01

+ Details

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

- References

No definition available.

+ Details

Name:	ifrs-full_PresentationOfLeasesForLesseeAbstract
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration