Related Party Transactions - Additional Information (Detail) - USD ($)		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Long-term debt		$ 3,071,000,000		$ 3,071,000,000		$ 4,340,000,000
Due to affiliates		799,000,000		799,000,000		3,300,000,000
Notional values of derivative contracts		419,000,000		419,000,000		1,765,000,000
Interest bearing deposits with banks		0		0		1,500,000,000
Derivative related liabilities		0		0		12,000,000
Derivative related expense (less than $1 million for the 3 months ended June 30, 2017)		1,000,000	$ 3,000,000	3,000,000	$ (112,000,000)
HSBC USA, Inc. [Member]
Related Party Transaction [Line Items]
Due to affiliates		0		0		2,500,000,000
HSBC USA, Inc. [Member] | Revolving Credit Facility [Member]
Related Party Transaction [Line Items]
Borrowing capacity of credit facility		5,000,000,000		$ 5,000,000,000
Debt instrument, term				364 days
Maximum maturity period for borrowings				5 years
Repayments of Lines of Credit				$ 2,500,000,000
Loss on extinguishment of debt				28,000,000
HSBC Holdings plc [Member]
Related Party Transaction [Line Items]
Due to affiliates		799,000,000		799,000,000		800,000,000
HSBC North America [Member] | Revolving Credit Facility [Member]
Related Party Transaction [Line Items]
Borrowing capacity of credit facility		1,000,000,000		$ 1,000,000,000		1,000,000,000
Debt instrument, term				364 days
Amount of credit facility outstanding		0		$ 0		0
HSBC Bank USA [Member]
Related Party Transaction [Line Items]
Notional values of derivative contracts		419,000,000		419,000,000		1,800,000,000
Fair value of our agreements with affiliate counterparties required the affiliate to provide collateral		50,000,000		50,000,000		317,000,000
Receivables services to affiliates		70,000,000		70,000,000		559,000,000
HSBC affiliates [Member]
Related Party Transaction [Line Items]
Due to affiliates	[1]	799,000,000		799,000,000		3,300,000,000
Interest bearing deposits with banks		0		0		1,500,000,000
HSBC Securities (USA) Inc. [Member]
Related Party Transaction [Line Items]
Receivable transaction assistance fees (less than $1 million for the 3 months ended June 30, 2017)		1,000,000	2,000,000	5,000,000	2,000,000
Discontinued Operations [Member]
Related Party Transaction [Line Items]
Derivative related expense (less than $1 million for the 3 months ended June 30, 2017)		1,000,000		$ 1,000,000
Series C Preferred Stock [Member]
Related Party Transaction [Line Items]
Number of shares of stock issued (shares)				1,000
Dividend paid on preferred stock		21,000,000	$ 21,000,000	$ 43,000,000	$ 43,000,000
Subordinated Debt [Member] | Public Subordinated Debt Issue Maturing 2021 [Member]
Related Party Transaction [Line Items]
Long-term debt		3,000,000,000		3,000,000,000
Discontinued Operations [Member] | Visa Class B Shares [Member] | HSBC USA, Inc. [Member]
Related Party Transaction [Line Items]
Notional values of derivative contracts		61,000,000		61,000,000		50,000,000
Derivative related liabilities		$ 6,000,000		$ 6,000,000		$ 5,000,000

[1] Due to affiliates includes amounts owed to HSBC and its subsidiaries as a result of direct debt issuances and excludes preferred stock.