Fee Income from Contracts with Customers - Disaggregation (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Other non-fee revenue	$ 169	$ 49	$ 357	$ 214
Total other revenues	448	343	901	829
Total Fee Income
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	279	294	544	615
Credit card fees, net
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	12	12	23	27
Trust and investment management fees
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	32	34	63	60
Account services
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	73	70	139	137
Credit facilities
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	76	71	149	171
Other fees
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	8	19	17	30
Other fees and commissions
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	157	160	305	338
Servicing and other fees from HSBC affiliates
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	77	87	151	188
Insurance
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	$ 1	$ 1	$ 2	$ 2