Intangible assets - Main amortization rates (Details)	12 Months Ended
Dec. 31, 2019
Exploration rights \| Minimum
Intangible assets
Description of useful life, intangible assets other than goodwill	UOP
Exploration rights \| Maximum
Intangible assets
Amortisation rate, intangible assets other than goodwill	33.00%
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	25.00%
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 2019-01-01
-Paragraph 118
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=38&code=ifrs-tx-2019-en-r&anchor=para_118_a&doctype=Standard
-URIDate 2019-03-27

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