Other comprehensive income - Items not reclassified to profit or loss (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Items not reclassified to profit or loss
Increase (decrease) in accumulated actuarial losses/profits	€ 157
Spain
Items not reclassified to profit or loss
Increase (decrease) in accumulated actuarial losses/profits	€ 41
Discount rates	1.40%	1.50%
United Kingdom
Items not reclassified to profit or loss
Increase (decrease) in accumulated actuarial losses/profits	€ 121
Discount rates	2.49%	2.79%
Inflation rates	3.15%	3.12%
Brazil
Items not reclassified to profit or loss
Increase (decrease) in accumulated actuarial losses/profits	€ 276
Discount rate actuarial assumptions \| Other Regions [Member]
Items not reclassified to profit or loss
Increase (decrease) in accumulated actuarial losses/profits	€ (281)
Pension benefits \| Brazil
Items not reclassified to profit or loss
Discount rates	9.53%	10.92%
Medical benefits \| Brazil
Items not reclassified to profit or loss
Discount rates	9.65%	10.84%

The discount rate used as the significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [member]]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2017-01-01
-Paragraph 144
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_144&doctype=Standard
-URIDate 2017-03-09

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- Definition

The expected rate of inflation that is used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [member]; Defined benefit obligation, at present value; Actuarial assumptions [member]]

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The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in financial assumptions that result in remeasurements of the net defined benefit liability (asset). Financial assumptions deal with items such as: (a) the discount rate; (b) benefit levels, excluding any cost of the benefits to be met by employees, and future salary; (c) in the case of medical benefits, future medical costs, including claim handling costs (ie the costs that will be incurred in processing and resolving claims, including legal and adjuster's fees); and (d) taxes payable by the plan on contributions relating to service before the reporting date or on benefits resulting from that service. [Refer: Net defined benefit liability (asset)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2017-01-01
-Paragraph 141
-Subparagraph c
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2017-03-01&anchor=para_141_c_iii&doctype=Standard
-URIDate 2017-03-09

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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.

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