Fair values of financial instruments carried at fair value - Sensitivity of fair values to reasonably possible alternative assumptions (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Favourable changes reflected in profit or loss	$ 2,233	$ 1,936
Unfavourable changes reflected in profit or loss	(1,729)	(1,475)
Favourable changes reflected in OCI	49	47
Un-favourable changes reflected in OCI	$ (49)	(50)
Confidence level corresponding to results of technique other than confidence level technique used for determining risk adjustment for non-financial risk	95.00%
Derivatives, trading assets and trading liabilities \| Derivatives, trading liabilities
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Favourable changes reflected in profit or loss	$ 483	481
Unfavourable changes reflected in profit or loss	(295)	(313)
Favourable changes reflected in OCI	0	0
Un-favourable changes reflected in OCI	0	0
Financial assets designated and otherwise mandatorily measured at fair value through profit or loss \| Financial liabilities designated at fair value
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Favourable changes reflected in profit or loss	1,750	1,434
Unfavourable changes reflected in profit or loss	(1,434)	(1,141)
Favourable changes reflected in OCI	0	0
Un-favourable changes reflected in OCI	0	0
Financial assets at fair value through other comprehensive income, category
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Line Items]
Favourable changes reflected in profit or loss	0	21
Unfavourable changes reflected in profit or loss	0	(21)
Favourable changes reflected in OCI	49	47
Un-favourable changes reflected in OCI	$ (49)	$ (50)

[Line Items] for Disclosure Of Fair Value Measurement Of Assets And Liabilities [Table]

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- Definition

Gain (Loss) Recognized In Other Comprehensive Income Due to Favourable Changes In Significant Unobservable Inputs

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- Definition

Gain (Loss) Recognized In Other Comprehensive Income Due to Unfavourable Changes In Significant Unobservable Inputs

+ References

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- Definition

Gain (Loss) Recognized In Profit Or Loss Due to Favourable Changes In Significant Unobservable Inputs

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- Definition

Gain (Loss) Recognized In Profit Or Loss Due to Unfavourable Changes In Significant Unobservable Inputs

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- Definition

The confidence level corresponding to the results of a technique other than the confidence level technique used for determining the risk adjustment for non-financial risk. [Refer: Risk adjustment for non-financial risk [member]]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 17
-IssueDate 2025-01-01
-Paragraph 119
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2025-en-r&anchor=para_119&doctype=Standard
-URIDate 2025-03-27

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