Segment Information - Narrative (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of subsidiaries [line items]
Revenues	€ 52,008	€ 52,036	€ 54,916
Inter-segment eliminations
Disclosure of subsidiaries [line items]
Revenues	(551)	(658)	€ (545)
Other companies and eliminations \| Telxius Telecom, S.A.
Disclosure of subsidiaries [line items]
Revenues	730	645
OIBDA	346	266
Capital expenditures (CapEx)	203	119
Other companies and eliminations \| Inter-segment eliminations \| Telxius Telecom, S.A.
Disclosure of subsidiaries [line items]
Revenues	€ 449	€ 451

The income arising in the course of an entity's ordinary activities. Income is increases in economic benefits during the accounting period in the form of inflows or enhancements of assets or decreases of liabilities that result in an increase in equity, other than those relating to contributions from equity participants.

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+ Details