Financial liabilities designated at fair value - Narrative (Details) - Financial liabilities designated at fair value - USD ($)	Dec. 31, 2025	Dec. 31, 2024
Disclosure of financial liabilities [line items]
Difference between carrying amount of financial liability and amount contractually required to pay at maturity to holder of obligation, more (less)	$ (2,691,000,000)	$ (4,365,000,000)
Accumulated decrease in fair value of financial liability, attributable to changes in credit risk of liability	2,252,000,000	1,655,000,000
HSBC Holdings
Disclosure of financial liabilities [line items]
Difference between carrying amount of financial liability and amount contractually required to pay at maturity to holder of obligation, more (less)	1,161,000,000	(17,000,000)
Accumulated decrease in fair value of financial liability, attributable to changes in credit risk of liability	$ 430,000,000	$ 540,000,000

The accumulated increase (decrease) in the fair value of financial liabilities that is attributable to changes in the credit risk of the liabilities. [Refer: Credit risk [member]; Market risk [member]; Increase (decrease) in fair value of financial liability, attributable to changes in credit risk of liability]

- Definition

The amount by which the carrying amount of a financial liability is more (less) than the amount that the entity would be contractually required to pay at maturity to the holder of the obligation. [Refer: Carrying amount [member]]

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