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
-Name IAS
-Number 19
-IssueDate 2024-01-01
-Paragraph 57
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=19&code=ifrs-tx-2024-en-r&anchor=para_57_a&doctype=Standard
-URIDate 2024-03-27

Retirement benefits - Narrative (Details) $ in Millions	12 Months Ended
Retirement benefits - Narrative (Details) $ in Millions	Dec. 31, 2024 USD ($) plan	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	$ (3,251)	$ (1,602)
Defined benefit plan obligation
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	66,054	78,024	$ 73,481
Defined benefit plan assets
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	$ (69,707)	(79,961)	(76,756)
The Netherlands
Disclosure of defined benefit plans [line items]
Local funding threshold	125.00%
Surplus (deficit)	$ 4,753	$ 3,520
Percentage of defined benefit liability related to active members	21.00%	23.00%
The Netherlands \| Defined benefit plan obligation
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	$ 23,577	$ 26,746	24,608
The Netherlands \| Defined benefit plan assets
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	$ (28,330)	$ (30,266)	(27,986)
UK
Disclosure of defined benefit plans [line items]
Defined benefit plans funded by final salary pension arrangements \| plan	4
Number of defined benefit plans that cannot be netted \| plan	3
Defined benefit plans closed to new employees \| plan	3
Defined benefit plans open to new members \| plan	2
Percentage of defined benefit liability related to active members	14.00%	16.00%
Actuarial funding valuation, frequency	3 years
Actuarial funding valuation, funding ratio	108.00%
UK \| Defined benefit plan obligation
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	$ 16,957	$ 19,074	17,791
UK \| Defined benefit plan assets
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	(19,560)	(22,320)	(21,963)
UK \| Funded pension plans
Disclosure of defined benefit plans [line items]
Surplus (deficit)	2,603	3,246
UK \| Unfunded pension plans
Disclosure of defined benefit plans [line items]
Surplus (deficit)	319	340
UK \| BG Pension Scheme
Disclosure of defined benefit plans [line items]
Surplus (deficit)	105
Defined benefit obligation, at present value	1,270
USA
Disclosure of defined benefit plans [line items]
Surplus (deficit)	638	$ 140
Gain on settlement of defined benefit liabilities	$ 101
Percentage of defined benefit liability related to active members	30.00%	23.00%
USA \| Defined benefit plan obligation
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	$ 9,596	$ 15,579	14,793
USA \| Defined benefit plan assets
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	(9,425)	(14,835)	(14,243)
USA \| Unfunded pension plans
Disclosure of defined benefit plans [line items]
Surplus (deficit)	(809)	(884)
Pensions
Disclosure of defined benefit plans [line items]
Estimate of contributions expected to be paid to plan for next annual reporting period	862
Pensions \| Funded pension plans \| Defined benefit plan obligation
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	59,915	71,473
Pensions \| Unfunded pension plans \| Defined benefit plan obligation
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	$ 3,261	3,450
Pensions \| The Netherlands \| Top of range
Disclosure of defined benefit plans [line items]
Percentage of average local funding requirement for additional payments	105.00%
Pensions \| The Netherlands \| Funded pension plans \| Defined benefit plan obligation
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	$ 23,577	26,746
Pensions \| UK \| Funded pension plans \| Defined benefit plan obligation
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	16,638	18,734
Pensions \| UK \| Unfunded pension plans \| Defined benefit plan obligation
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	319	340
Pensions \| USA \| Funded pension plans \| Defined benefit plan obligation
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	8,787	14,695
Pensions \| USA \| Unfunded pension plans \| Defined benefit plan obligation
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	809	884
OPEB \| Defined benefit plan obligation
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	2,878	3,101	$ 2,879
OPEB \| Unfunded pension plans \| Defined benefit plan obligation
Disclosure of defined benefit plans [line items]
Net defined benefit liability (asset)	2,878	3,101
OPEB \| USA
Disclosure of defined benefit plans [line items]
Surplus (deficit)	$ (2,337)	$ (2,267)