XML 197 R178.htm IDEA: XBRL DOCUMENT v3.21.1

Share-based Payment Arrangements - Summary of ASE Inc. Option Plans Outstanding Share Options (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
ASE Inc. option plans [member] | Fourth share options exercise price [member]
Disclosure of terms and conditions of share-based payment arrangement [Line Items]
Range of Exercise Price Per Share	$ 45.2
Weighted Average Remaining Contractual Life (Years)	3 months 18 days	6 months
ASE Inc. option plans [member] | Fifth share options exercise price [member]
Disclosure of terms and conditions of share-based payment arrangement [Line Items]
Range of Exercise Price Per Share	$ 73.0	$ 73.0
Weighted Average Remaining Contractual Life (Years)	4 years 8 months 12 days	5 years 8 months 12 days
ASE Inc. option plans [member] | Bottom of range [member] | Fourth share options exercise price [member]
Disclosure of terms and conditions of share-based payment arrangement [Line Items]
Range of Exercise Price Per Share		$ 40.8
ASE Inc. option plans [member] | Top of range [member] | Fourth share options exercise price [member]
Disclosure of terms and conditions of share-based payment arrangement [Line Items]
Range of Exercise Price Per Share		45.2
The Company Option Plans [member] | First share options exercise price [member]
Disclosure of terms and conditions of share-based payment arrangement [Line Items]
Range of Exercise Price Per Share	$ 52.9	$ 54.4
Weighted Average Remaining Contractual Life (Years)	7 years 10 months 24 days	8 years 10 months 24 days

X

- Definition

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

+ References

No definition available.

+ Details

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

X

- Definition

The exercise price of outstanding share options.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2020-01-01
-Paragraph 45
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_45_d&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_ExercisePriceOfOutstandingShareOptions2019
Namespace Prefix:	ifrs-full_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The weighted average remaining contractual life of outstanding share options. [Refer: Weighted average [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2020-01-01
-Paragraph 45
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2020-en-r&anchor=para_45_d&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_WeightedAverageRemainingContractualLifeOfOutstandingShareOptions2019
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=asx_ASEIncOptionPlansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_RangesOfExercisePricesForOutstandingShareOptionsAxis=asx_FourthShareOptionsExercisePriceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_RangesOfExercisePricesForOutstandingShareOptionsAxis=asx_FifthShareOptionsExercisePriceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

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

X

- Details

Name:	ifrs-full_TypesOfSharebasedPaymentArrangementsAxis=asx_TheCompanyOptionPlansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	ifrs-full_RangesOfExercisePricesForOutstandingShareOptionsAxis=asx_FirstShareOptionsExercisePriceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: