Earnings per share - Basic and diluted earnings per share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	6 Months Ended
Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021
Earnings per share [abstract]
Profit	$ 8,289	$ 5,331	$ 7,276
Basic, number of shares (in shares)	19,954	20,183	20,211
Effect of dilutive potential ordinary shares (in shares)	130	103	97
Diluted, number of shares (in shares)	20,084	20,286	20,308
Basic, amount per share (in dollars per share)	$ 0.42	$ 0.26	$ 0.36
Diluted, amount per share (in dollars per share)	$ 0.41	$ 0.26	$ 0.36

The weighted average number of ordinary shares outstanding plus the weighted average number of ordinary shares that would be issued on the conversion of all the dilutive potential ordinary shares into ordinary shares. [Refer: Ordinary shares [member]; Weighted average [member]]

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The amount of profit (loss) attributable to ordinary equity holders of the parent entity (the numerator) divided by the weighted average number of ordinary shares outstanding during the period (the denominator).

+ References

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The amount of profit (loss) attributable to ordinary equity holders of the parent entity (the numerator), divided by the weighted average number of ordinary shares outstanding during the period (the denominator), both adjusted for the effects of all dilutive potential ordinary shares. [Refer: Ordinary shares [member]; Weighted average [member]]

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The number of dilutive potential ordinary shares that relate to the assumed conversion of the entity's convertible instruments.

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The profit (loss) attributable to ordinary equity holders of the parent entity. [Refer: Profit (loss)]

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The number of ordinary shares outstanding at the beginning of the period, adjusted by the number of ordinary shares bought back or issued during the period multiplied by a time-weighting factor.

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