Employees - Summary of Movements in Assets (Details) - EUR (€) € in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	€ 2,993	€ 287
Employee contributions	12	13
Settlements	1	1
Actual return on plan assets (excluding amounts in net finance income/charge)	(6,483)	1,958
Change in asset ceiling excluding amounts included in interest expenses	(184)	(17)
Employer contributions	303	394
Benefit payments	0	0
Other	13	1
Currency retranslation	(63)	127
Net defined benefit liability (asset)	2,569	2,993
Plan assets
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	26,643	24,006
Employee contributions	12	13
Settlements	0	0
Actual return on plan assets (excluding amounts in net finance income/charge)	(6,483)	1,958
Change in asset ceiling excluding amounts included in interest expenses	(184)	(17)
Interest income	496	344
Employer contributions	303	394
Benefit payments	(1,184)	(1,135)
Other	(2)	(47)
Currency retranslation	(468)	1,127
Net defined benefit liability (asset)	19,133	26,643
UK
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	2,879	1,351
Employee contributions	1	0
Settlements	0	0
Actual return on plan assets (excluding amounts in net finance income/charge)	(4,870)	1,092
Change in asset ceiling excluding amounts included in interest expenses	0	0
Employer contributions	66	100
Benefit payments	0	0
Other	0	0
Currency retranslation	(99)	126
Net defined benefit liability (asset)	1,866	2,879
UK \| Plan assets
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	14,332	12,499
Employee contributions	1	0
Settlements	0	0
Actual return on plan assets (excluding amounts in net finance income/charge)	(4,870)	1,092
Change in asset ceiling excluding amounts included in interest expenses	0	0
Interest income	264	181
Employer contributions	66	100
Benefit payments	(511)	(501)
Other	0	0
Currency retranslation	(578)	961
Net defined benefit liability (asset)	8,704	14,332
The Netherlands
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	1,162	527
Employee contributions	0	0
Settlements	0	0
Actual return on plan assets (excluding amounts in net finance income/charge)	(668)	560
Change in asset ceiling excluding amounts included in interest expenses	0	0
Employer contributions	8	72
Benefit payments	0	0
Other	(1)	0
Currency retranslation	0	0
Net defined benefit liability (asset)	1,609	1,162
The Netherlands \| Plan assets
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	6,099	5,587
Employee contributions	0	0
Settlements	0	0
Actual return on plan assets (excluding amounts in net finance income/charge)	(668)	560
Change in asset ceiling excluding amounts included in interest expenses	0	0
Interest income	66	39
Employer contributions	8	72
Benefit payments	(161)	(159)
Other	(1)	0
Currency retranslation	0	0
Net defined benefit liability (asset)	5,343	6,099
Rest of world
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	(1,048)	(1,591)
Employee contributions	11	13
Settlements	1	1
Actual return on plan assets (excluding amounts in net finance income/charge)	(945)	306
Change in asset ceiling excluding amounts included in interest expenses	(184)	(17)
Employer contributions	229	222
Benefit payments	0	0
Other	14	1
Currency retranslation	36	1
Net defined benefit liability (asset)	(906)	(1,048)
Rest of world \| Plan assets
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	6,212	5,920
Employee contributions	11	13
Settlements	0	0
Actual return on plan assets (excluding amounts in net finance income/charge)	(945)	306
Change in asset ceiling excluding amounts included in interest expenses	(184)	(17)
Interest income	166	124
Employer contributions	229	222
Benefit payments	(512)	(475)
Other	(1)	(47)
Currency retranslation	110	166
Net defined benefit liability (asset)	€ 5,086	€ 6,212

The decrease (increase) in net defined benefit liability (asset) resulting from contributions to a defined benefit plan by the employer. [Refer: Net defined benefit liability (asset); Defined benefit plans [member]]

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-URIDate 2021-03-24

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- Definition

The decrease (increase) in the net defined benefit liability (asset) resulting from contributions to a defined benefit plan by plan participants. [Refer: Net defined benefit liability (asset); Defined benefit plans [member]]

+ References

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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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The decrease (increase) in the net defined benefit liability (asset) resulting from the gain (loss) on changes in the effect of limiting a net defined benefit asset to the asset ceiling, excluding amounts included in interest income or expense. [Refer: Interest income (expense); Net defined benefit liability (asset); Increase (decrease) in net defined benefit liability (asset) resulting from interest expense (income)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

The increase (decrease) in the net defined benefit liability (asset) resulting from changes in foreign exchange rates. [Refer: Net defined benefit liability (asset)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

The increase (decrease) in the net defined benefit liability (asset) resulting from changes that the entity does not separately disclose in the same statement or note. [Refer: Net defined benefit liability (asset)]

+ References

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

The increase (decrease) in the net defined benefit liability (asset) resulting from the passage of time. [Refer: Interest expense; Net defined benefit liability (asset)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
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- Definition

The amount of deficit or 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/2003/role/disclosureRef
-Name IAS
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- Definition

The decrease (increase) in the net defined benefit liability (asset) resulting from payments from the plan. [Refer: Net defined benefit liability (asset)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 19
-IssueDate 2021-01-01
-Paragraph 141
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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: Decrease (increase) in net defined benefit liability (asset) resulting from gains (losses) arising from settlements; Net defined benefit liability (asset); Defined benefit plans [member]]

+ References

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- Definition

The decrease (increase) in the net defined benefit liability (asset) resulting from the return on plan assets, excluding amounts included in interest income or expense. The return on plan assets is interest, dividends and other revenue derived from the plan assets, together with realised and unrealised gains or losses on the plan assets, less any costs of managing plan assets and less any tax payable by the plan itself, other than tax included in the actuarial assumptions used to measure the present value of the defined benefit obligation. [Refer: Plan assets [member]; Net defined benefit liability (asset); Actuarial assumptions [member]; Increase (decrease) in net defined benefit liability (asset) resulting from interest expense (income)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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