Earnings/(loss) per ordinary share - Summary of Earnings Per Ordinary Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Basic earnings/(loss) per ordinary share
Profit/(loss) available for equity holders	$ 266	$ (260)	$ 385
Basic weighted average number of ordinary shares (millions)	183	182	183
Basic earnings/(loss) per ordinary share	$ 1.454	$ (1.429)	$ 2.104
Diluted earnings/(loss) per ordinary share
Profit/(loss) available for equity holders	$ 266	$ (260)	$ 385
Diluted weighted average number of ordinary shares (millions)	184	182	184
Diluted earnings/(loss) per ordinary share	$ 1.446	$ (1.429)	$ 2.092
Diluted weighted average number of ordinary shares is calculated as:
Basic weighted average number of ordinary shares	183	182	183
Dilutive potential ordinary shares	1		1
Adjusted weighted average shares	184	182	184

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).

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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 exercise of the entity's share options.

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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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