Assets held for sale and liabilities directly associated with assets held for sale (Details Textual) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
DisclosureOfDiscontinuedOperationsExplanatoryLineItems [Line Items]
Liabilities included in disposal groups classified as held for sale	€ 87
Tigaz Zrt [Member]
DisclosureOfDiscontinuedOperationsExplanatoryLineItems [Line Items]
% Ownership	48.55%	48.55%
Percentage of Ownership Interest Divested	98.99%
Tigaz dso [Member]
DisclosureOfDiscontinuedOperationsExplanatoryLineItems [Line Items]
% Ownership	100.00%
Current assets or disposal groups classified as held for sale	€ 31
Current liabilities included in disposal groups classified as held for sale	27
Tigaz dso [Member] \| Gross carrying amount [member]
DisclosureOfDiscontinuedOperationsExplanatoryLineItems [Line Items]
Non-current assets or disposal groups classified as held for sale	241
Liabilities included in disposal groups classified as held for sale	65
Met holding ag [Member]
DisclosureOfDiscontinuedOperationsExplanatoryLineItems [Line Items]
Non-current assets or disposal groups classified as held for sale	323
Liabilities included in disposal groups classified as held for sale	€ 87
Unimar llc [Member]
DisclosureOfDiscontinuedOperationsExplanatoryLineItems [Line Items]
% Ownership	50.00%
Non-current assets or disposal groups classified as held for sale	€ 29
Lasmo sanga sanga [Member]
DisclosureOfDiscontinuedOperationsExplanatoryLineItems [Line Items]
% Ownership	26.25%
Non-current assets or disposal groups classified as held for sale	€ 53
Current assets or disposal groups classified as held for sale	37
Current liabilities included in disposal groups classified as held for sale	10
Liabilities included in disposal groups classified as held for sale	€ 22

The amount of current assets or disposal group classified as held for sale.

No definition available.

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- Definition

The amount of current lliabilities included in disposal groups classified as held for sale.

+ References

No definition available.

+ Details

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- References

No definition available.

+ Details

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- Definition

The percentage of ownership interest divested.

+ References

No definition available.

+ Details

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- Definition

The amount of liabilities included in disposal groups classified as held for sale. [Refer: Liabilities; Disposal groups classified as held for sale [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
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-IssueDate 2017-01-01
-Paragraph 38
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-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-URIDate 2017-03-09

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- Definition

The amount of non-current assets or disposal groups classified as held for sale. [Refer: Disposal groups classified as held for sale [member]]

+ References

+ Details

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- Definition

The proportion of ownership interest in a subsidiary attributable to the entity. [Refer: Subsidiaries [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2017-01-01
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-URIDate 2017-03-09

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-URIDate 2017-03-09

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