Fee Income from Contracts with Customers - Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Other non-fee revenues	$ 165	$ 96
Total other revenues	486	384
Total Fee Income
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	321	288
Credit card fees, net
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	15	10
Trust and investment management fees
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	26	29
Account services
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	67	70
Credit facilities
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	100	83
Other fees
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	11	12
Other fees and commissions
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	178	165
Servicing and other fees from HSBC affiliates
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	101	83
Insurance
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	$ 1	$ 1