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Pensions and Other Post-employment Benefit Obligations - Summary of Amounts Recognized in the Consolidated Statement of Financial Position (Detail) - EUR (€) € in Millions	Dec. 31, 2017	Dec. 31, 2016
Disclosure of variation in financial position [line items]
Present value of funded obligation	€ 691	€ 721
Fair value of plan assets	(387)	(391)
Deficit of funded plans	304	330
Present value of unfunded obligation	360	405
Net liability arising from defined benefit obligation	664	735
Pension benefits [member]
Disclosure of variation in financial position [line items]
Present value of funded obligation	691	721
Fair value of plan assets	(387)	(391)
Deficit of funded plans	304	330
Present value of unfunded obligation	110	132
Net liability arising from defined benefit obligation	414	462
Other benefits [member]
Disclosure of variation in financial position [line items]
Present value of unfunded obligation	250	273
Net liability arising from defined benefit obligation	€ 250	€ 273

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- Definition

Disclosure of variation in financial position [line items]

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Present value of unfunded obligation.

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- Definition

The present value, without deducting any plan assets, of expected future payments required to settle the obligation resulting from employee service in the current and prior periods. [Refer: Plan assets, at fair value]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

The amount of non-current net defined benefit liability. [Refer: Net defined benefit liability]

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- Definition

The fair value of defined benefit plan assets. Plan assets comprise assets held by a long-term employee benefit fund and qualifying insurance policies. [Refer: At fair value [member]]

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The present value of the defined benefit obligation, less the fair value of the plan assets (if any). [Refer: Plan assets [member]]

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