Interest in associates and joint ventures - Associates and joint ventures commentary (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Interests In Other Entities [Abstract]
Tax on profit	$ 306	$ 440

Share Of Profit (Loss) From Continuing Operations Of Associates And Joint Ventures Accounted For Using Equity Method, Tax Expense (Income)

No definition available.

Name:	hsbc_ShareOfProfitLossFromContinuingOperationsOfAssociatesAndJointVenturesAccountedForUsingEquityMethodTaxExpenseIncome
Namespace Prefix:	hsbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration