Cash dividend percentage on dividend distribution.

No definition available.

Name:	asx_CashDividendPercentageOnDividendDistribution
Namespace Prefix:	asx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of ordinary shares per ADS.

+ References

No definition available.

+ Details

Name:	asx_NumberOfOrdinarySharesPerADS
Namespace Prefix:	asx_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of legal reserve on share capital.

+ References

No definition available.

+ Details

Name:	asx_PercentageOfLegalReserveOnShareCapital
Namespace Prefix:	asx_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

+ References

No definition available.

+ Details

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

- Definition

The number of shares issued by the entity.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 106
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_106_d&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_NumberOfSharesIssued
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of shares that have been authorised and issued, reduced by treasury shares held. [Refer: Treasury shares]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 79
-Subparagraph a
-Clause iv
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_79_a_iv&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_NumberOfSharesOutstanding
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The nominal value per share.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2021-01-01
-Paragraph 79
-Subparagraph a
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2021-en-r&anchor=para_79_a_iii&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_ParValuePerShare
Namespace Prefix:	ifrs-full_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted average share price. [Refer: Weighted average [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2021-01-01
-Paragraph 45
-Subparagraph c
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2021-en-r&anchor=para_45_c&doctype=Standard
-URIDate 2021-03-24

+ Details

Name:	ifrs-full_WeightedAverageSharePrice2019
Namespace Prefix:	ifrs-full_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	ifrs-full_ClassesOfShareCapitalAxis=asx_AmericanDepositorySharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfShareCapitalAxis=ifrs-full_OrdinarySharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_TitleOfIndividualAxis=asx_BoardOfDirectorsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_TopOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_RangeAxis=ifrs-full_BottomOfRangeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Equity - Additional Information (Detail)	12 Months Ended
Equity - Additional Information (Detail)	Dec. 31, 2021 shares $ / shares	Dec. 31, 2021 shares $ / shares $ / shares	Dec. 31, 2021 $ / shares shares	Nov. 08, 2021 $ / shares shares	Nov. 08, 2021 $ / shares shares	Dec. 31, 2020 shares
Disclosure of classes of share capital [line items]
Number of shares represented by each ADS	2	2
Percentage of legal reserve on share capital	25.00%	25.00%
American depository shares (ADs) [member]
Disclosure of classes of share capital [line items]
Number of shares represented by each ADS	2	2
Number of shares outstanding	157,164,000	157,164,000	157,164,000			107,964,000
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Number of shares outstanding	314,328,000	314,328,000	314,328,000			215,927,000
Ordinary shares [member] \| Board of Directors [Member]
Disclosure of classes of share capital [line items]
Number of ordinary shares issued	55,000,000	55,000,000	55,000,000	55,000,000	55,000,000
Top of range [member]
Disclosure of classes of share capital [line items]
Percentage of cash dividend on dividend distribution	30.00%	30.00%
Top of range [member] \| Ordinary shares [member]
Disclosure of classes of share capital [line items]
Number of ordinary shares issued	53,067,000	53,067,000	53,067,000
Weighted average share price \| (per share)	$ 104.2	$ 3.8
Top of range [member] \| Ordinary shares [member] \| Board of Directors [Member]
Disclosure of classes of share capital [line items]
Par value per share \| (per share)				$ 150	$ 5
Bottom of range [member] \| Ordinary shares [member]
Disclosure of classes of share capital [line items]
Number of ordinary shares issued	1,933,000	1,933,000	1,933,000
Weighted average share price \| (per share)	$ 106.4	$ 3.8
Bottom of range [member] \| Ordinary shares [member] \| Board of Directors [Member]
Disclosure of classes of share capital [line items]
Par value per share \| (per share)	$ 90	$ 90	$ 3	$ 90	$ 3