XML 144 R128.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Retirement Benefit Plans - Summary of Movements in Net Defined Benefit Liability (Asset) (Detail) $ in Thousands, $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 TWD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2016 TWD ($) | Dec. 31, 2015 TWD ($)
Disclosure of net defined benefit liability (asset) [line items] |  |  |  |
Beginning balance | $ 3,972,517 | $ 134,026 | $ 3,999,947 | $ 4,171,806
Current service cost | 278,412 | 9,393 | 329,838 | 335,655
Past service cost and gain on settlements | (68,979) | (2,328) |  |
Net interest expense (income) | 53,663 | 1,811 | 58,031 | 75,533
Recognized in profit or loss | 263,096 | 8,876 | 387,869 | 411,188
Return on plan assets (excluding amounts included in net interest) | 52,124 | 1,759 | 54,549 | 12,426
Actuarial loss arising from changes in financial assumptions | 56,860 | 1,918 | 156,193 | 309,695
Actuarial loss (gain) arising from experience adjustments | (315,090) | (10,631) | 200,723 | (243,363)
Actuarial loss (gain) arising from changes in demographic assumptions | 762 | 26 | 5,716 | (15,847)
Recognized in other comprehensive income | (205,344) | (6,928) | 417,181 | 62,911
Contributions from the employer | (484,790) | (16,356) | (807,232) | (611,581)
Benefits paid from the Group | (96,575) | (3,258) | (36,033) | (43,088)
Exchange differences on foreign plans | 120,361 | 4,061 | 10,785 | 8,711
Ending balance | 3,569,265 | 120,421 | 3,972,517 | 3,999,947
Defined benefit obligation [member] |  |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |  |
Beginning balance | 8,389,884 | 283,060 | 7,973,676 | 7,674,293
Current service cost | 278,412 | 9,393 | 329,838 | 335,655
Past service cost and gain on settlements | (68,979) | (2,328) |  |
Net interest expense (income) | 157,404 | 5,311 | 167,111 | 183,889
Recognized in profit or loss | 366,837 | 12,376 | 496,949 | 519,544
Actuarial loss arising from changes in financial assumptions | 56,860 | 1,918 | 156,193 | 309,695
Actuarial loss (gain) arising from experience adjustments | (315,090) | (10,631) | 200,723 | (243,363)
Actuarial loss (gain) arising from changes in demographic assumptions | 762 | 26 | 5,716 | (15,847)
Recognized in other comprehensive income | (257,468) | (8,687) | 362,632 | 50,485
Benefits paid from the pension fund | (690,830) | (23,307) | (308,471) | (192,928)
Benefits paid from the Group | (96,575) | (3,258) | (36,033) | (43,088)
Liabilities assumed in a business combination |  |  | 535 |
Exchange differences on foreign plans | 198,790 | 6,707 | (99,404) | (34,630)
Ending balance | 7,910,638 | 266,891 | 8,389,884 | 7,973,676
Fair value of plan assets [member] |  |  |  |
Disclosure of net defined benefit liability (asset) [line items] |  |  |  |
Beginning balance | (4,417,367) | (149,034) | (3,973,729) | (3,502,487)
Net interest expense (income) | (103,741) | (3,500) | (109,080) | (108,356)
Recognized in profit or loss | (103,741) | (3,500) | (109,080) | (108,356)
Return on plan assets (excluding amounts included in net interest) | 52,124 | 1,759 | 54,549 | 12,426
Recognized in other comprehensive income | 52,124 | 1,759 | 54,549 | 12,426
Contributions from the employer | (484,790) | (16,356) | (807,232) | (611,581)
Benefits paid from the pension fund | 690,830 | 23,307 | 308,471 | 192,928
Liabilities assumed in a business combination |  |  | (535) |
Exchange differences on foreign plans | (78,429) | (2,646) | 110,189 | 43,341
Ending balance | $ (4,341,373) | $ (146,470) | $ (4,417,367) | $ (3,973,729)

X
- Definition Actuarial gains losses arising from experience adjustments. + References No definition available. + Details
Name: | asx_ActuarialGainsLossesArisingFromExperienceAdjustments
Namespace Prefix: | asx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Post-employment benefit expense, defined benefit plans excluding executive managers. + References No definition available. + Details
Name: | asx_PostemploymentBenefitExpenseDefinedBenefitPlansExcludingExecutiveManagers
Namespace Prefix: | asx_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in demographic assumptions that result in remeasurements of the net defined benefit liability (asset). Demographic assumptions deal with matters such as: (a) mortality; (b) rates of employee turnover, disability and early retirement; (c) the proportion of plan members with dependants who will be eligible for benefits; (d) the proportion of plan members who will select each form of payment option available under the plan terms; and (e) claim rates under medical plans. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 141 -Subparagraph c -Clause ii -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_c_ii&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_ActuarialGainsLossesArisingFromChangesInDemographicAssumptionsNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in financial assumptions that result in remeasurements of the net defined benefit liability (asset). Financial assumptions deal with items such as: (a) the discount rate; (b) benefit levels, excluding any cost of the benefits to be met by employees, and future salary; (c) in the case of medical benefits, future medical costs, including claim handling costs (ie the costs that will be incurred in processing and resolving claims, including legal and adjuster's fees); and (d) taxes payable by the plan on contributions relating to service before the reporting date or on benefits resulting from that service. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 141 -Subparagraph c -Clause iii -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_c_iii&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_ActuarialGainsLossesArisingFromChangesInFinancialAssumptionsNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of benefits paid or payable for retirement benefit plans. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 26 -IssueDate 2017-01-01 -Paragraph 35 -Subparagraph b -Clause v -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=26&date=2017-03-01&anchor=para_35_b_v&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_BenefitsPaidOrPayable
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The decrease (increase) in net defined benefit liability (asset) resulting from contributions to a defined benefit plan by the employer. [Refer: Net defined benefit liability (asset); Defined benefit plans [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 141 -Subparagraph f -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_f&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_ContributionsToPlanByEmployerNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from employee service in the current period. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 141 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_a&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_CurrentServiceCostNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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_DisclosureOfNetDefinedBenefitLiabilityAssetLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from business combinations and disposals. [Refer: Business combinations [member]; Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 141 -Subparagraph h -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_h&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_IncreaseDecreaseThroughBusinessCombinationsAndDisposalsNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from changes in foreign exchange rates. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 141 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_e&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_IncreaseDecreaseThroughChangesInForeignExchangeRatesNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from the passage of time. [Refer: Interest expense; Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 141 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_b&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_InterestExpenseIncomeNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of deficit or surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 140 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_140_a&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_LiabilityAssetOfDefinedBenefitPlans
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount of other comprehensive income, before tax, related to gains (losses) on remeasurements of defined benefit plans, which comprise actuarial gains and losses; the return on plan assets, excluding amounts included in net interest on the net defined benefit liability (asset); and any change in the effect of the asset ceiling, excluding amounts included in net interest on the net defined benefit liability (asset). [Refer: Other comprehensive income, before tax; Defined benefit plans [member]; Plan assets [member]; Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 91 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_91_b&doctype=Standard -URIDate 2017-03-09 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 7 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_7&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_OtherComprehensiveIncomeBeforeTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The increase (decrease) in the net defined benefit liability (asset) resulting from past service cost. Past service cost is the change in the present value of the defined benefit obligation for employee service in prior periods, resulting from a plan amendment (the introduction or withdrawal of, or changes to, a defined benefit plan) or a curtailment (a significant reduction by the entity in the number of employees covered by a plan). [Refer: Net defined benefit liability (asset); Defined benefit plans [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 141 -Subparagraph d -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_d&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_PastServiceCostNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The decrease (increase) in the net defined benefit liability (asset) resulting from payments from the plan. [Refer: Net defined benefit liability (asset)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 141 -Subparagraph g -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_g&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_PaymentsFromPlanNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The decrease (increase) in the net defined benefit liability (asset) resulting from the return on plan assets. The return on plans assets is interest, dividends and other revenue derived from the plan assets, together with realised and unrealised gains or losses on the plan assets, less any costs of managing plan assets and less any tax payable by the plan itself, other than tax included in the actuarial assumptions used to measure the present value of the defined benefit obligation. [Refer: Plan assets [member]; Net defined benefit liability (asset); Actuarial assumptions [member]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 19 -IssueDate 2017-01-01 -Paragraph 141 -Subparagraph c -Clause i -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_c_i&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_ReturnOnPlanAssetsNetDefinedBenefitLiabilityAsset
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | ifrs-full_NetDefinedBenefitLiabilityAssetAxis=ifrs-full_PresentValueOfDefinedBenefitObligationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_NetDefinedBenefitLiabilityAssetAxis=ifrs-full_PlanAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |