Provisions, income tax liabilities and other liabilities - Remeasurement of Net Defined-benefit (Asset)/Liability (Actuarial Gains and Losses) (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disclosure of defined benefit plans [line items]
Gains/(losses) on financial assumptions	€ 171	€ (654)	€ (686)
France
Disclosure of defined benefit plans [line items]
Actuarial gains/(losses) arising during the period	(3)	156	106
Gains/(losses) on experience adjustments	16	(120)	60
Gains/(losses) on demographic assumptions	0	0	0
Gains/(losses) on financial assumptions	(19)	276	46
Germany
Disclosure of defined benefit plans [line items]
Actuarial gains/(losses) arising during the period	(98)	205	113
Gains/(losses) on experience adjustments	(54)	(620)	182
Gains/(losses) on demographic assumptions	0	0	0
Gains/(losses) on financial assumptions	(44)	825	(69)
US
Disclosure of defined benefit plans [line items]
Actuarial gains/(losses) arising during the period	(25)	382	156
Gains/(losses) on experience adjustments	(7)	(287)	23
Gains/(losses) on demographic assumptions	18	129	51
Gains/(losses) on financial assumptions	(36)	540	82
UK
Disclosure of defined benefit plans [line items]
Actuarial gains/(losses) arising during the period	(44)	(131)	237
Gains/(losses) on experience adjustments	(12)	(1,328)	35
Gains/(losses) on demographic assumptions	11	54	125
Gains/(losses) on financial assumptions	€ (43)	€ 1,143	€ 77

The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in demographic assumptions that result in remeasurements of the net defined benefit liability (asset). Demographic assumptions deal with matters such as: (a) mortality; (b) rates of employee turnover, disability and early retirement; (c) the proportion of plan members with dependants who will be eligible for benefits; (d) the proportion of plan members who will select each form of payment option available under the plan terms; and (e) claim rates under medical plans. [Refer: Net defined benefit liability (asset)]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2023-01-01
-Paragraph 141
-Subparagraph c
-Clause ii
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2023-en-r&anchor=para_141_c_ii&doctype=Standard
-URIDate 2023-03-23

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- Definition

The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in financial assumptions that result in remeasurements of the net defined benefit liability (asset). Financial assumptions deal with items such as: (a) the discount rate; (b) benefit levels, excluding any cost of the benefits to be met by employees, and future salary; (c) in the case of medical benefits, future medical costs, including claim handling costs (ie the costs that will be incurred in processing and resolving claims, including legal and adjuster's fees); and (d) taxes payable by the plan on contributions relating to service before the reporting date or on benefits resulting from that service. [Refer: Net defined benefit liability (asset)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2023-01-01
-Paragraph 141
-Subparagraph c
-Clause iii
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2023-en-r&anchor=para_141_c_iii&doctype=Standard
-URIDate 2023-03-23

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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.

+ References

No definition available.

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- Definition

The decrease (increase) in a net defined benefit liability (asset) resulting from the remeasurement of that net defined benefit liability (asset). [Refer: Net defined benefit liability (asset)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2023-01-01
-Paragraph 141
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2023-en-r&anchor=para_141_c&doctype=Standard
-URIDate 2023-03-23

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- Definition

Actuarial gains/(losses) on experience adjustments.

+ References

No definition available.

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