Other information about investments - Other significant investments - Exploration & Production (Details)	12 Months Ended
	Dec. 31, 2023 EUR (€)	Dec. 31, 2023 AUD ($)	Dec. 31, 2023 EGP (ج.م.)	Dec. 31, 2023 VEF	Dec. 31, 2023 USD ($)	Dec. 31, 2022 EUR (€)
Other significant investments
Share capital	€ 4,005,000,000					€ 4,005,000,000
ENI SpA
Other significant investments
Share capital	€ 4,005,358,876					€ 4,005,358,876
Exploration & Production \| Italy \| Other significant investments One [member]
Other significant investments
Company name	BF SpA (#)
Registered office	Jolanda di Savoia (FE)
Country of operation	Italy
Share capital	€ 261,883,391
Consolidation or valuation method	F.V.
Exploration & Production \| Italy \| Other significant investments One [member] \| Eni Natural Energies SpA [Member]
Other significant investments
% Ownership	5.32%
Exploration & Production \| Italy \| Other significant investments One [member] \| Third parties
Other significant investments
% Ownership	94.68%
Exploration & Production \| Italy \| Other Significant Investments Two [Member]
Other significant investments
Company name	Consorzio Universitario in Ingegneria per la Qualità e l’Innovazione
Registered office	Pisa
Country of operation	Italy
Share capital	€ 142,000
Consolidation or valuation method	F.V.
Exploration & Production \| Italy \| Other Significant Investments Two [Member] \| ENI SpA
Other significant investments
% Ownership	12.50%
Exploration & Production \| Italy \| Other Significant Investments Two [Member] \| Third parties
Other significant investments
% Ownership	87.50%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Three [Member]
Other significant investments
Company name	Administradora del Golfo de Paria Este SA
Registered office	Caracas (Venezuela)
Country of operation	Venezuela
Share capital \| VEF				VEF 0
Consolidation or valuation method	F.V.
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Three [Member] \| Eni Venezuela BV
Other significant investments
% Ownership	19.50%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Three [Member] \| Third parties
Other significant investments
% Ownership	80.50%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Four [Member]
Other significant investments
Company name	Brass LNG Ltd
Registered office	Lagos (Nigeria)
Country of operation	Nigeria
Share capital \| $					$ 1,000,000
Consolidation or valuation method	F.V.
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Four [Member] \| Eni Int. NA NV Sarl
Other significant investments
% Ownership	20.48%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Four [Member] \| Third parties
Other significant investments
% Ownership	79.52%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Five [Member]
Other significant investments
Company name	Darwin LNG Pty Ltd
Registered office	West Perth (Australia)
Country of operation	Australia
Share capital \| $		$ 187,569,921.42
Consolidation or valuation method	F.V.
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Five [Member] \| Eni G&P LNG Aus. BV
Other significant investments
% Ownership	10.99%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Five [Member] \| Third parties
Other significant investments
% Ownership	89.01%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Six [Member]
Other significant investments
Company name	New Liberty Residential Urban Renewal Company Llc (former New Liberty Residential Co Llc)
Registered office	West Trenton (USA)
Country of operation	USA
Share capital \| $					0
Consolidation or valuation method	F.V.
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Six [Member] \| Eni Oil & Gas Inc
Other significant investments
% Ownership	17.50%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Six [Member] \| Third parties
Other significant investments
% Ownership	82.50%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Seven [Member]
Other significant investments
Company name	Nigeria LNG Ltd
Registered office	Port Harcourt (Nigeria)
Country of operation	Nigeria
Share capital \| $					$ 1,138,207,000
Consolidation or valuation method	F.V.
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Seven [Member] \| Eni Int. NA NV Sarl
Other significant investments
% Ownership	10.40%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Seven [Member] \| Third parties
Other significant investments
% Ownership	89.60%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Eight [Member]
Other significant investments
Company name	North Caspian Operating Company NV
Registered office	The Hague (Netherlands)
Country of operation	Kazakhstan
Share capital	€ 128,520
Consolidation or valuation method	F.V.
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Eight [Member] \| Agip Caspian Sea BV
Other significant investments
% Ownership	16.81%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Eight [Member] \| Third parties
Other significant investments
% Ownership	83.19%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Nine [Member]
Other significant investments
Company name	Petrolera Güiria SA
Registered office	Caracas (Venezuela)
Country of operation	Venezuela
Share capital \| VEF				VEF 0
Consolidation or valuation method	F.V.
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Nine [Member] \| Eni Venezuela BV
Other significant investments
% Ownership	19.50%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Nine [Member] \| Third parties
Other significant investments
% Ownership	80.50%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Ten [Member]
Other significant investments
Company name	Torsina Oil Co
Registered office	Cairo (Egypt)
Country of operation	Egypt
Share capital \| ج.م.			ج.م. 20,000
Consolidation or valuation method	F.V.
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Ten [Member] \| Ieoc Production BV
Other significant investments
% Ownership	12.50%
Exploration & Production \| Foreign (outside Italy) \| Other Significant Investments Ten [Member] \| Third parties
Other significant investments
% Ownership	87.50%