XML 121 R62.htm IDEA: XBRL DOCUMENT
v3.20.4

Description of business (Details) $ in Millions | Dec. 31, 2020 USD ($) segment | Apr. 09, 2019
--- | --- | ---
Corporate Information And Statement Of IFRS Compliance [Abstract] |  |
Number of reporting segments | segment | 2 |
Shares received in spin-off |  | 0.2
Total asset and net sales threshold | $ | $ 5 |

X
- Definition Corporate Information And Statement Of IFRS Compliance [Abstract] + References No definition available. + Details
Name: | alc_CorporateInformationAndStatementOfIFRSComplianceAbstract
Namespace Prefix: | alc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number Of Reportable Segments + References No definition available. + Details
Name: | alc_NumberOfReportableSegments
Namespace Prefix: | alc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Stockholders' Equity, Spin-Off Conversion Ratio, Shares Received + References No definition available. + Details
Name: | alc_StockholdersEquitySpinOffConversionRatioSharesReceived
Namespace Prefix: | alc_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total Asset and Net Sales Threshold To Be Included Consolidated Statements + References No definition available. + Details
Name: | alc_TotalAssetandNetSalesThresholdToBeIncludedConsolidatedStatements
Namespace Prefix: | alc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant