INTEREST BEARING LOANS AND BORROWINGS - Short-term loans and borrowings (Details) ¥ in Thousands, $ in Thousands	Dec. 31, 2020 USD ($)	Dec. 31, 2020 CNY (¥)	Dec. 31, 2019 CNY (¥)
Loans and borrowings
Short-term bonds		¥ 2,411,256	¥ 9,331,488
Bank and other loans, current		20,738,030	21,238,166
Gold leasing arrangements			7,018,609
Current portion of lease liabilities		828,272	1,358,654
Current portion of medium-term notes		7,100,711
Current portion of long-term bank and other loans		3,629,014	3,339,687
Current portion of long term borrowings Including bonds		13,969,253	21,048,438
Interest-bearing loans and borrowings	$ 5,319,124	34,707,283	42,286,604
JPY
Loans and borrowings
Interest-bearing loans and borrowings		15,000	17,000
USD
Loans and borrowings
Interest-bearing loans and borrowings		1,312,000	4,006,000
Secured
Loans and borrowings
Bank and other loans, current		863,738	465,000
Guaranteed
Loans and borrowings
Bank and other loans, current		50,000
Unsecured
Loans and borrowings
Bank and other loans, current		¥ 19,824,292	¥ 20,773,166

The current portion of bank and other loans.

No definition available.

Name:	ach_BankAndOtherLoansCurrent
Namespace Prefix:	ach_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of gold lease arrangements that (a) the entity expects to settle in its normal operating cycle; (b) the entity holds primarily for the purpose of trading; (c) are due to be settled within twelve months after the reporting period; or (d) the entity does not have an unconditional right to defer settlement for at least twelve months after the reporting period.

+ References

No definition available.

+ Details

Name:	ach_CurrentGoldLeaseArrangements
Namespace Prefix:	ach_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The current portion of long-term bank loans and other loans received.

+ References

No definition available.

+ Details

Name:	ach_CurrentPortionOfLongTermBankLoansAndOtherLoansReceived
Namespace Prefix:	ach_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The current portion of non-current borrowings including bonds.

+ References

No definition available.

+ Details

Name:	ach_CurrentPortionOfLongTermBorrowingsIncludingBonds
Namespace Prefix:	ach_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The current portion of medium-term bonds and long-term bonds issued.

+ References

No definition available.

+ Details

Name:	ach_CurrentPortionOfMediumTermBondsAndLongTermBondsIssued
Namespace Prefix:	ach_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The current unsecured notes and bonds issued.

+ References

No definition available.

+ Details

Name:	ach_CurrentUnsecuredNotesAndBondsIssued
Namespace Prefix:	ach_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This concept does not have any references.

+ References

No definition available.

+ Details

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

- Definition

The amount of current borrowings and current portion of non-current borrowings. [Refer: Borrowings]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 55
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_55&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_CurrentBorrowingsAndCurrentPortionOfNoncurrentBorrowings
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of current lease liabilities. [Refer: Lease liabilities]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 16
-IssueDate 2020-01-01
-Paragraph 47
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2020-en-r&anchor=para_47_b&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_CurrentLeaseLiabilities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	srt_CurrencyAxis=currency_JPY
Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

Name:	srt_CurrencyAxis=currency_USD
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BorrowingsByNameAxis=ach_SecuredBankAndOtherLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BorrowingsByNameAxis=ach_GuaranteedBankAndOtherLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_BorrowingsByNameAxis=ach_UnsecuredBankAndOtherLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: