HSBC Holdings' subsidiaries, joint ventures and associates - Joint Ventures (Details)	12 Months Ended
Dec. 31, 2019
Global Payments Technology Mexico S.A. De C.V.
Disclosure of joint ventures [line items]
Group interest percent	50.00%
HCM Holdings Limited (In Liquidation)
Disclosure of joint ventures [line items]
Group interest percent	50.99%
House Network Sdn Bhd
Disclosure of joint ventures [line items]
Group interest percent	25.00%
HSBC Jintrust Fund Management Company Limited
Disclosure of joint ventures [line items]
Group interest percent	49.00%
ProServe Bermuda Limited
Disclosure of joint ventures [line items]
Group interest percent	50.00%
Vaultex UK Limited
Disclosure of joint ventures [line items]
Group interest percent	50.00%

The proportion of ownership interest in a joint venture attributable to the entity. [Refer: Joint ventures [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2018-01-01
-Paragraph 17
-Subparagraph b
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=27&date=2018-03-01&anchor=para_17_b_iii&doctype=Standard
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 27
-IssueDate 2018-01-01
-Paragraph 16
-Subparagraph b
-Clause iii
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=27&date=2018-03-01&anchor=para_16_b_iii&doctype=Standard
-URIDate 2018-03-16

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 12
-IssueDate 2018-01-01
-Paragraph 21
-Subparagraph a
-Clause iv
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=12&date=2018-03-01&anchor=para_21_a_iv&doctype=Standard
-URIDate 2018-03-16

Name:	ifrs-full_ProportionOfOwnershipInterestInJointVenture
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration