Debt securities in issue - Summary of debt securities in issue (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	$ 2,623,757	$ 2,655,014
Trading liabilities
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	84,904	75,266
Financial liabilities designated at fair value
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	145,502	157,439
Bonds and medium-term notes
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	166,537	176,570
Other debt securities in issue
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	26,573	41,538
Debt securities
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	193,110	218,108
Debt securities \| Trading liabilities
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	1,792	1,582
Debt securities \| Financial liabilities designated at fair value
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	112,761	121,034
Debt securities \| At cost
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	78,557	95,492
Issued by HSBC Holdings
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	122,531	115,864
Issued by HSBC Holdings \| Financial liabilities designated at fair value
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	32,418	25,664
Issued by HSBC Holdings \| Debt securities
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	94,301	83,653
Issued by HSBC Holdings \| Debt securities \| Financial liabilities designated at fair value
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	26,818	19,624
Issued by HSBC Holdings \| Debt securities \| At cost
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	$ 67,483	$ 64,029

- Definition

The amount of liabilities that are: (a) a contractual obligation: (i) to deliver cash or another financial asset to another entity; or (ii) to exchange financial assets or financial liabilities with another entity under conditions that are potentially unfavourable to the entity; or (b) a contract that will, or may be, settled in the entity’s own equity instruments and is: (i) a non-derivative for which the entity is, or may be, obliged to deliver a variable number of the entity’s own equity instruments; or (ii) a derivative that will, or may be, settled other than by the exchange of a fixed amount of cash or another financial asset for a fixed number of the entity’s own equity instruments. For this purpose, rights, options or warrants to acquire a fixed number of the entity’s own equity instruments for a fixed amount of any currency are equity instruments if the entity offers the rights, options or warrants pro rata to all of its existing owners of the same class of its own non-derivative equity instruments. Also, for those purposes the entity’s own equity instruments do not include puttable financial instruments that are classified as equity instruments in accordance with paragraphs 16A-16B of IAS 32, instruments that impose on the entity an obligation to deliver to another party a pro rata share of the net assets of the entity only on liquidation and are classified as equity instruments in accordance with paragraphs 16C-16D of IAS 32, or instruments that are contracts for the future receipt or delivery of the entity’s own equity instruments. As an exception, an instrument that meets the definition of a financial liability is classified as an equity instrument if it has all the features and meets the conditions in paragraphs 16A-16B or paragraphs 16C-16D of IAS 32. [Refer: Financial instruments, class [member]; Financial assets; Derivatives [member]]

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