Significant accounting policies, judgements, estimates and assumptions - Judgements and estimates made in assessing impact of COVID-19 (Details) $ in Millions	12 Months Ended
Dec. 31, 2021 USD ($)
Disclosure of changes in accounting estimates [line items]
Change in discount rate	$ 1,332
Increase (decrease) through other changes, property, plant and equipment	1,000
Decommissioning
Disclosure of changes in accounting estimates [line items]
Change in discount rate	$ 1,252

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.

No definition available.

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- Definition

The increase (decrease) in other provisions resulting from a change in discount rate. [Refer: Other provisions]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 37
-IssueDate 2021-01-01
-Paragraph 84
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=37&code=ifrs-tx-2021-en-r&anchor=para_84_e&doctype=Standard
-URIDate 2021-03-24

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- Definition

The increase (decrease) in property, plant and equipment resulting from changes that the entity does not separately disclose in the same statement or note. [Refer: Property, plant and equipment]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 16
-IssueDate 2021-01-01
-Paragraph 73
-Subparagraph e
-Clause ix
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=16&code=ifrs-tx-2021-en-r&anchor=para_73_e_ix&doctype=Standard
-URIDate 2021-03-24

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