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

The number of other equity instruments (ie other than share options) granted in a share-based payment arrangement.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2021-01-01
-Paragraph 47
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2021-en-r&anchor=para_47_b&doctype=Standard
-URIDate 2021-03-24

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 2
-IssueDate 2021-01-01
-Paragraph 45
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2021-en-r&anchor=para_45&doctype=Standard
-URIDate 2021-03-24

Name:	ifrs-full_NumberOfInstrumentsOtherEquityInstrumentsGranted
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

The number of other equity instruments (ie other than share options) forfeited in a share-based payment arrangement.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 2
-IssueDate 2021-01-01
-Paragraph 45
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=2&code=ifrs-tx-2021-en-r&anchor=para_45&doctype=Standard
-URIDate 2021-03-24

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

The number of other equity instruments (ie other than share options) outstanding in a share-based payment arrangement.

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

The weighted average exercise price of other equity instruments (ie other than share options) exercised or vested in a share-based payment arrangement. [Refer: Weighted average [member]]

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

The weighted average exercise price of other equity instruments (ie other than share options) forfeited in a share-based payment arrangement. [Refer: Weighted average [member]]

Name:	ifrs-full_WeightedAverageExercisePriceOfOtherEquityInstrumentsForfeitedInSharebasedPaymentArrangement2019
Namespace Prefix:	ifrs-full_
Data Type:	num:perShareItemType
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Period Type:	duration

The weighted average exercise price of other equity instruments (ie other than share options) granted in a share-based payment arrangement. [Refer: Weighted average [member]]

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Namespace Prefix:	ifrs-full_
Data Type:	num:perShareItemType
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The weighted average exercise price of other equity instruments (ie other than share options) outstanding in a share-based payment arrangement. [Refer: Weighted average [member]]

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

Number of warrants exercised.

No definition available.

Name:	otly_NumberOfWarrantsExercised
Namespace Prefix:	otly_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Number of warrants redeemed.

No definition available.

Name:	otly_NumberOfWarrantsRedeemed
Namespace Prefix:	otly_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Weighted average exercise price of warrants redeemed.

No definition available.