Fee Income from Contracts with Customers - Disaggregation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Other non-fee revenues	$ 113	$ 444	$ 670
Total other revenues	1,237	1,535	1,854
Total Fee Income
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	1,124	1,091	1,184
Credit card fees, net
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	37	38	67
Trust and investment management fees
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	108	132	132
Account services
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	290	251	264
Credit facilities
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	320	268	302
Other fees
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	42	48	53
Other fees and commissions
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	652	567	619
Servicing and other fees from HSBC affiliates
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	321	347	354
Insurance
Disaggregation of Revenue [Line Items]
Total fee income from contracts with customers	$ 6	$ 7	$ 12