Pension and other post-employment benefits - Summary of information on plan assets and defined benefit obligation per country (Detail) - EUR (€) € in Millions	Dec. 31, 2023	Dec. 31, 2022
Disclosure of net defined benefit liability (asset) [line items]
Plan assets	€ 2,678	€ 2,637
Defined benefit obligation	2,288	2,159
Funded Status	390	478
- Other assets	554	617
- Other liabilities	(164)	(139)
Netherlands
Disclosure of net defined benefit liability (asset) [line items]
Plan assets	331	310
Defined benefit obligation	426	400
Funded Status	(95)	(90)
USA
Disclosure of net defined benefit liability (asset) [line items]
Plan assets	257	248
Defined benefit obligation	245	230
Funded Status	12	18
United Kingdom
Disclosure of net defined benefit liability (asset) [line items]
Plan assets	1,257	1,277
Defined benefit obligation	790	750
Funded Status	467	527
Belgium
Disclosure of net defined benefit liability (asset) [line items]
Plan assets	516	507
Defined benefit obligation	473	475
Funded Status	43	32
Other countries
Disclosure of net defined benefit liability (asset) [line items]
Plan assets	317	295
Defined benefit obligation	353	305
Funded Status	€ (37)	€ (10)

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]

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

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

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No definition available.

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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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- Definition

The amount of surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [member]]

+ References

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

The amount of deficit in a defined benefit plan. [Refer: Defined benefit plans [member]]

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

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