Business combinations and other significant transactions - Business combinations (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2020
Disclosure of detailed information about business combination [line items]
Identifiable assets acquired (liabilities assumed)		$ 617
Non-controlling interest in acquiree recognised at acquisition date		$ 574
Petrohawk Energy Corporation
Disclosure of detailed information about business combination [line items]
Cash consideration for acquisition	$ (3,480)

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- Definition

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

+ References

No definition available.

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- Definition

The amount recognised as of the acquisition date for net identifiable assets acquired or liabilities assumed in a business combination. [Refer: Business combinations [member]]

+ References

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- Definition

The amount of non-controlling interest in the acquiree recognised at the acquisition date for business combinations in which the acquirer holds less than 100 per cent of the equity interests in the acquiree at the acquisition date. [Refer: Business combinations [member]]

+ References

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