Financial Statements of HSBC USA Inc. (Parent) Statement of Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income:
Other interest income	$ 43	$ 44	$ 48
Other income	58	68	195
Expenses:
Other Interest Expense	33	99	5
Provision for credit losses	293	258	34
Income (loss) from continuing operations before income tax expense (benefit)	(910)	682	1,445
Income tax benefit	(338)	(227)	(439)
Net income (loss)	(1,045)	1,018	1,564
Parent [Member]
Income:
Dividendsfrom banking subsidiaries	0	1	5
Dividends from other subsidiaries	57	2	2
Interest from subsidiaries	67	67	74
Interest from other HSBC affiliates	27	17	20
Other interest income	19	19	22
Other securities gains, net	21	0	1
Other income from subsidiaries	(290)	(131)	(89)
Other income from other HSBC Affiliates	472	(18)	217
Other income	(155)	312	(30)
Total income	218	269	222
Expenses:
Interest to subsidiaries	69	70	70
Interest to other HSBC Affiliates	65	48	19
Other Interest Expense	198	224	216
Provision for credit losses	0	(1)	0
Other expenses with Other HSBC Affiliates	19	12	4
Other expenses	8	2	3
Total expenses	359	355	312
Income (loss) from continuing operations before income tax expense (benefit)	(141)	(86)	(90)
Income tax benefit	47	62	47
Loss before equity in undistributed income of subsidiaries	(94)	(24)	(43)
Equity in undistributed income (loss) of subsidiaries	(951)	1,042	1,607
Net income (loss)	$ (1,045)	$ 1,018	$ 1,564