Employees - Summary of Charge to Operating Profit (Detail) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of defined benefit plans [Abstract]
Current service cost	€ (245)	€ (226)	€ (271)
Employee contributions	18	17	17
Special termination benefits	(4)	(6)	(9)
Past service cost including (losses)/gains on curtailments	23	32	129
Settlements	4	(2)	6
Defined contribution plans	(195)	(187)	(197)
Total operating cost	(399)	(372)	(325)
Finance income/(cost)	(96)	(94)	(121)
Net impact on the income statement (before tax)	€ (495)	€ (466)	€ (446)

The increase (decrease) in the net defined benefit liability (asset) resulting from employee service in the current period. [Refer: Net defined benefit liability (asset)]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2016-01-13
-Paragraph 141
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2016-03-30&anchor=para_141_a&doctype=Standard
-URIDate 2016-03-31

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- References

No definition available.

+ Details

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- Definition

The amount of employee contributions to retirement benefit plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 26
-IssueDate 2016-01-13
-Paragraph 35
-Subparagraph b
-Clause ii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=26&date=2016-03-30&anchor=para_35_b_ii&doctype=Standard
-URIDate 2016-03-31

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- Definition

The increase (decrease) in the net defined benefit liability (asset) resulting from past service cost and gains (losses) arising from settlements. [Refer: Gains (losses) arising from settlements, net defined benefit liability (asset); Net defined benefit liability (asset)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2016-01-13
-Paragraph 141
-Subparagraph d
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2016-03-30&anchor=para_141_d&doctype=Standard
-URIDate 2016-03-31

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- Definition

The decrease (increase) in the net defined benefit liability (asset) resulting from payments from the plan in respect of settlements. [Refer: Gains (losses) arising from settlements, net defined benefit liability (asset); Net defined benefit liability (asset); Defined benefit plans [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2016-01-13
-Paragraph 141
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-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2016-03-30&anchor=para_141_g&doctype=Standard
-URIDate 2016-03-31

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- Definition

The amount of post-employment benefit expense relating to defined contribution plans. Defined contribution plans are post-employment benefit plans under which an entity pays fixed contributions into a separate entity (a fund) and will have no legal or constructive obligation to pay further contributions if the fund does not hold sufficient assets to pay all employee benefits relating to employee service in the current and prior periods.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2016-01-13
-Paragraph 53
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2016-03-30&anchor=para_53&doctype=Standard
-URIDate 2016-03-31

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- Definition

The amount of expense in relation to termination benefits. Termination benefits are employee benefits provided in exchange for the termination of an employee's employment as a result of either: (a) an entity's decision to terminate an employee's employment before the normal retirement date; or (b) an employee's decision to accept an offer of benefits in exchange for the termination of employment. [Refer: Employee benefits expense]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2016-01-13
-Paragraph 171
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2016-03-30&anchor=para_171&doctype=Standard
-URIDate 2016-03-31

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- Definition

The item consist of (a) interest cost on Pensions liabilities, which is the increase during a period in the present value of a defined benefit obligation which arises because the benefits are one period closer to settlement and (b) interest income on plan assets.

+ References

No definition available.

+ Details

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- Definition

Net effect of pensions and similar obligations on operating profit before tax.

+ References

No definition available.

+ Details

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- Definition

Post employment benefit costs.

+ References

No definition available.

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