CONSOLIDATED STATEMENT OF INCOME (LOSS) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income:
Loans		$ 2,202	$ 2,856	$ 2,589
Securities		897	1,188	1,131
Trading securities		288	291	213
Short-term investments		143	573	645
Other		42	82	77
Total interest income		3,572	4,990	4,655
Interest expense:
Deposits		755	1,475	1,072
Short-term borrowings		69	231	172
Long-term debt		558	1,137	1,123
Other		16	35	36
Total interest expense		1,398	2,878	2,403
Net interest income		2,174	2,112	2,252
Provision for credit losses		810	195	(73)
Provision for credit losses		736	195	(73)
Net interest income after provision for credit losses		1,364	1,917	2,325
Other revenues:
Other revenues		1,091	1,184	1,236
Trading revenue		273	591	625
Other securities gains, net		137	88	24
Gain (loss) on instruments designated at fair value and related derivatives		34	(13)	19
Other income		7	16	6
Total other revenues	[1]	1,535	1,854	1,899
Operating expenses:
Salaries and employee benefits		767	822	830
Support services from HSBC affiliates		1,551	1,638	1,603
Occupancy expense, net		281	197	185
Goodwill impairment		784	365	0
Other expenses		498	479	1,020
Total operating expenses		3,881	3,501	3,638
Income (loss) before income tax		(982)	270	586
Income tax expense (benefit)		(42)	157	266
Net income (loss)		(940)	113	320
Credit card fees, net [Member]
Other revenues:
Other revenues		38	67	50
Trust and investment management fees [Member]
Other revenues:
Other revenues		132	132	135
Other fees and commissions [Member]
Other revenues:
Other revenues		567	619	684
Servicing and other fees from HSBC affiliates [Member]
Other revenues:
Other revenues		$ 347	$ 354	$ 356

[1] See Note 24, "Business Segments," for a reconciliation of total other revenues on a U.S. GAAP basis to other operating income for each business segment under the Group Reporting Basis.