Fee Income from Contracts with Customers - Disaggregation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Other non-fee revenue	$ 512	$ 448	$ 113
Total other revenues	1,652	1,595	1,237
Total Fee Income
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	1,140	1,147	1,124
Credit card fees, net
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	49	45	37
Trust and investment management fees
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	134	136	108
Account services
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	283	275	290
Credit facilities
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	310	296	320
Other fees
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	33	48	42
Other fees and commissions
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	626	619	652
Servicing and other fees from HSBC affiliates
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	327	343	321
Insurance
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	$ 4	$ 4	$ 6