Revenues and other income - Additional information (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues and other income
Recovery of cost share of right-of-use assets pertaining to partners of unincorporated joint operations	€ 281	€ 357	€ 368

Recovery of cost share of right-of-use assets pertaining to partners of non-incorporated joint operations

No definition available.

Name:	e_RecoveryOfCostShareOfRightOfUseAssetsPertainingToPartnersOfNonIncorporatedJointOperations
Namespace Prefix:	e_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration