XML 124 R65.htm IDEA: XBRL DOCUMENT
v3.20.4

Selected accounting policies - Additional information (Details) - USD ($) $ in Millions |  | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jul. 01, 2019 | Dec. 31, 2019 | Jun. 30, 2019 | Dec. 31, 2020
Disclosure of expected impact of initial application of new standards or interpretations [line items] |  |  |  |
Cash flow projection period |  |  |  | 5 years
Technology-based intangible asset, SAP ERP [member] |  |  |  |
Disclosure of expected impact of initial application of new standards or interpretations [line items] |  |  |  |
Finite-lived intangible asset, useful life | 10 years |  | 7 years |
Amortisation decrease due to change in useful life |  | $ 5 |  | $ 10
Amortisation decrease due to change in useful life, annual amount |  |  |  | $ 10
Bottom of range [member] | Other intangible assets (including software) [member] |  |  |  |
Disclosure of expected impact of initial application of new standards or interpretations [line items] |  |  |  |
Finite-lived intangible asset, useful life |  | 3 years | 3 years | 3 years
Top of range [member] | Other intangible assets (including software) [member] |  |  |  |
Disclosure of expected impact of initial application of new standards or interpretations [line items] |  |  |  |
Finite-lived intangible asset, useful life |  | 10 years | 7 years | 10 years

X
- Definition Amortisation, Intangible Assets Other Than Goodwill, Increase (Decrease) Due To Change In Useful Life + References No definition available. + Details
Name: | alc_AmortisationIntangibleAssetsOtherThanGoodwillIncreaseDecreaseDueToChangeInUsefulLife
Namespace Prefix: | alc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amortisation, Intangible Assets Other Than Goodwill, Increase (Decrease) Due To Change In Useful Life, Annual Amount Through End Of Useful Life + References No definition available. + Details
Name: | alc_AmortisationIntangibleAssetsOtherThanGoodwillIncreaseDecreaseDueToChangeInUsefulLifeAnnualAmountThroughEndOfUsefulLife
Namespace Prefix: | alc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Period Over Which Management Has Projected Cash Flows + References No definition available. + Details
Name: | alc_PeriodOverWhichManagementHasProjectedCashFlows
Namespace Prefix: | alc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Useful Lives Or Amortisation Rates, Intangible Assets Other Than Goodwill, Period + References No definition available. + Details
Name: | alc_UsefulLivesOrAmortisationRatesIntangibleAssetsOtherThanGoodwillPeriod
Namespace Prefix: | alc_
Data Type: | xbrli:durationItemType
Balance Type: | na
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_DescriptionOfExpectedImpactOfInitialApplicationOfNewStandardsOrInterpretationsLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis=alc_TechnologybasedIntangibleAssetSAPERPMember
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_ClassesOfIntangibleAssetsOtherThanGoodwillAxis=ifrs-full_OtherIntangibleAssetsMember
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: |