Note 25 - Post-employment and other employee benefit commitments - Sensitivity Analysis (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Sensitivity Analysis Line Items
Other long term employee benefits	€ 67	€ 69	€ 68
Discount Rate [Member]
Sensitivity Analysis Line Items
Variation Of Reasonably Possible Increase In Actuarial Assumption	50	50
Increase	€ (352)	€ (367)
Decrease	€ 386	€ 401
Rate of salary increase [Member]
Sensitivity Analysis Line Items
Variation Of Reasonably Possible Increase In Actuarial Assumption	50	50
Increase	€ 5	€ 9
Decrease	€ (5)	€ (9)
Rate of pension increase [Member]
Sensitivity Analysis Line Items
Variation Of Reasonably Possible Increase In Actuarial Assumption	50	50
Increase	€ 23	€ 28
Decrease	€ (22)	€ (27)
Medical cost trend rate [Member]
Sensitivity Analysis Line Items
Variation Of Reasonably Possible Increase In Actuarial Assumption	100	100
Increase	€ 290	€ 263
Decrease	€ (225)	€ (204)
Change in obligation from each additional year of longevity [Member]
Sensitivity Analysis Line Items
Variation Of Reasonably Possible Increase In Actuarial Assumption	-	-
Increase	€ 155	€ 121
Decrease	€ 0	€ 0

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- Definition

Variation Of Reasonably Possible Increase In Actuarial Assumption, in Basic Points

+ References

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+ References

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- Definition

The increase (decrease) in a defined benefit obligation that would have been caused by a decrease in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2016-01-13
-Paragraph 145
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2016-03-30&anchor=para_145_a&doctype=Standard
-URIDate 2016-03-31

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- Definition

The increase (decrease) in a defined benefit obligation that would have been caused by an increase in a significant actuarial assumption that was reasonably possible at the end of the reporting period. [Refer: Actuarial assumptions [member]]

+ References

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