Litigation and Regulatory Matters - Additional Information (Details)	1 Months Ended			12 Months Ended		36 Months Ended
	Jun. 30, 2020 financial_institution	Mar. 31, 2018 USD ($)	Jan. 31, 2018 transaction	Dec. 31, 2014 USD ($) trust	Dec. 31, 2013 USD ($)	Dec. 31, 2007 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Loss Contingencies [Line Items]
Estimate of reasonably possible loss							$ 150,000,000
FX DPA | HSBC Holdings plc
Loss Contingencies [Line Items]
Litigation settlement agreement, compliance period			3 years
Number of Transactions Investigated | transaction			2
South African Competition Tribunal, Revised Complaint
Loss Contingencies [Line Items]
Number of financial institutions | financial_institution	28
Mortgage Securitization Activity Related Litigation | HSBC Securities
Loss Contingencies [Line Items]
Mortgage securitization loan purchased and sold						$ 24,000,000,000
Mortgage securitization outstanding loan purchase and sold							$ 2,700,000,000	$ 3,100,000,000
Deutsche Bank Alleged Breach of Representation
Loss Contingencies [Line Items]
Damages sought					$ 508,000,000
Mortgage Securitizationn Pool Trust Litigation
Loss Contingencies [Line Items]
Damages sought				$ 38,000,000,000
Number of identified trusts | trust				280
Rigoberto Vasquez and Eva Garcia et al v. Hong Kong and Shanghai Banking Corporation Ltd., HSBC Bank USA, N.A., et al.
Loss Contingencies [Line Items]
Damages sought		$ 37,000,000