Intangible assets - Main amortization rates (Details)	12 Months Ended
Dec. 31, 2020
Exploration rights
Intangible assets
Description of useful life, intangible assets other than goodwill	UOP
Transport rights of natural gas
Intangible assets
Amortisation rate, intangible assets other than goodwill	3.00%
Other concessions, licenses, trademarks and similar items \| Minimum
Intangible assets
Amortisation rate, intangible assets other than goodwill	3.00%
Other concessions, licenses, trademarks and similar items \| Maximum
Intangible assets
Amortisation rate, intangible assets other than goodwill	33.00%
Service concession arrangements \| Minimum
Intangible assets
Amortisation rate, intangible assets other than goodwill	20.00%
Service concession arrangements \| Maximum
Intangible assets
Amortisation rate, intangible assets other than goodwill	33.00%
Capitalized costs for customer acquisition \| Minimum
Intangible assets
Amortisation rate, intangible assets other than goodwill	17.00%
Capitalized costs for customer acquisition \| Maximum
Intangible assets
Amortisation rate, intangible assets other than goodwill	33.00%
Other intangible assets \| Minimum
Intangible assets
Amortisation rate, intangible assets other than goodwill	4.00%
Other intangible assets \| Maximum
Intangible assets
Amortisation rate, intangible assets other than goodwill	20.00%

The amortisation rate used for intangible assets other than goodwill. [Refer: Intangible assets other than goodwill]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 38
-IssueDate 2020-01-01
-Paragraph 118
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2020-en-r&anchor=para_118_a&doctype=Standard
-URIDate 2020-01-01

+ Details

Name:	ifrs-full_AmortisationRateIntangibleAssetsOtherThanGoodwill
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of useful life used for intangible assets other than goodwill. [Refer: Intangible assets other than goodwill]

+ References

+ Details

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

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

- Details

Name:	ifrs-full_ClassesOfIntangibleAssetsAndGoodwillAxis=ifrs-full_IntangibleExplorationAndEvaluationAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfIntangibleAssetsAndGoodwillAxis=e_TransportRightsOfNaturalGasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfIntangibleAssetsAndGoodwillAxis=e_ConcessionsLicensesTrademarksAndSimilarItemsOtherThanTransportOfNaturalGasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	ifrs-full_ClassesOfIntangibleAssetsAndGoodwillAxis=ifrs-full_ServiceConcessionArrangementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfIntangibleAssetsAndGoodwillAxis=ifrs-full_CustomerrelatedIntangibleAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ifrs-full_ClassesOfIntangibleAssetsAndGoodwillAxis=ifrs-full_OtherIntangibleAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: