Related Party Transactions - Additional Information (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Related Party Transaction [Line Items]
Long-term debt	$ 24,604,000,000		$ 24,604,000,000		$ 22,847,000,000
Due from Affiliates	5,080,000,000		5,080,000,000		5,328,000,000
Derivative, notional amount	5,437,400,000,000		5,437,400,000,000		5,457,095,000,000
Rent from related party	13,000,000	13,000,000	27,000,000	25,000,000
HSBC Mexico [Member]
Related Party Transaction [Line Items]
Extended loans and lines of credit	1,100,000,000		1,100,000,000		500,000,000
HNAH [Member]
Related Party Transaction [Line Items]
Long-term debt	4,000,000,000		4,000,000,000
Senior note interest rate period			90 days
Amount outstanding under the loan agreement	0		0		0
HSBC Investment Bahamas [Member]
Related Party Transaction [Line Items]
Amount outstanding under the loan agreement	0		0		0
Maximum borrowing capacity	1,000,000,000		1,000,000,000		1,000,000,000
HSBC [Member]
Related Party Transaction [Line Items]
Amount outstanding under the loan agreement	0		0		0
Maximum borrowing capacity	500,000,000		500,000,000		500,000,000
HNAI [Member]
Related Party Transaction [Line Items]
Maximum borrowing capacity	150,000,000		150,000,000		150,000,000
HSBC Finance Corporation [Member]
Related Party Transaction [Line Items]
Extended loans and lines of credit	5,000,000,000		5,000,000,000
Debt term			364 days
Due from Affiliates	3,014,000,000		3,014,000,000		3,015,000,000
HSBC Finance Corporation [Member] | Extended Uncommitted Revolving Credit Facility [Member]
Related Party Transaction [Line Items]
Loan And Lease Receivable Revolving Line Of Credit Outstanding	3,000,000,000		3,000,000,000
Extended unsecured uncommitted credit facility to certain subsidiary maturity			15 years
HSBC Finance Corporation [Member] | Extended Uncommitted Revolving Credit Facility [Member] | Maturity Date, September 2017 [Member]
Related Party Transaction [Line Items]
Maturing amount of credit agreement	512,000,000		512,000,000
HSBC Finance Corporation [Member] | Extended Uncommitted Revolving Credit Facility [Member] | Maturity Date, January 2018 [Member]
Related Party Transaction [Line Items]
Maturing amount of credit agreement	1,500,000,000		1,500,000,000
HSBC Finance Corporation [Member] | Extended Uncommitted Revolving Credit Facility [Member] | Maturity Date, September 2018 [Member]
Related Party Transaction [Line Items]
Maturing amount of credit agreement	1,000,000,000		1,000,000,000
HSBC Finance Corporation [Member] | Extended committed revolving credit facility [Member]
Related Party Transaction [Line Items]
Loan And Lease Receivable Revolving Line Of Credit Outstanding	0		0		0
Loan And Lease Receivable Unused Line Of Credit Facility	1,000,000,000		1,000,000,000		1,000,000,000
HSBC Finance Corporation [Member] | Residential Mortgage [Member]
Related Party Transaction [Line Items]
Residential mortgage loans servicing	907,000,000		907,000,000		983,000,000
HMUS [Member]
Related Party Transaction [Line Items]
Extended loans and lines of credit	6,700,000,000		6,700,000,000		3,800,000,000
Loan And Lease Receivable Revolving Line Of Credit Outstanding	720,000,000		720,000,000		199,000,000
Due from Affiliates	720,000,000		720,000,000		199,000,000
HSBC Bank Brasil [Member]
Related Party Transaction [Line Items]
Extended loans and lines of credit	1,100,000,000		1,100,000,000		1,500,000,000
Loan And Lease Receivable Revolving Line Of Credit Outstanding	1,100,000,000		1,100,000,000		1,000,000,000
Other Affiliates [Member]
Related Party Transaction [Line Items]
Loan And Lease Receivable Revolving Line Of Credit Outstanding	246,000,000		246,000,000		1,114,000,000
Other Affiliates [Member] | Extended committed revolving credit facility [Member]
Related Party Transaction [Line Items]
Loan And Lease Receivable Revolving Line Of Credit Outstanding	0		0		0
Loan And Lease Receivable Unused Line Of Credit Facility	2,300,000,000		2,300,000,000		2,300,000,000
Regency [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Liquidity Facility, Notional Amount	2,400,000,000		2,400,000,000
Hsbc Finance And Other Hsbc Affiliates [Member]
Related Party Transaction [Line Items]
Derivative, notional amount	1,138,700,000,000		1,138,700,000,000		1,210,600,000,000
Fair value of derivative receivables	953,000,000		953,000,000		845,000,000
Five Year Floating Rate Note Maturing August 2014 [Member] | HNAH [Member]
Related Party Transaction [Line Items]
Senior notes	1,000,000,000		1,000,000,000
Five Year Floating Rate Note Maturing August 2014 [Member] | HNAH [Member] | Senior Notes [Member]
Related Party Transaction [Line Items]
Debt term			5 years
Loan Maturing in Three Equal Installments on April 2015, 2016, 2017 [Member] | HNAH [Member]
Related Party Transaction [Line Items]
Senior notes	3,000,000,000		3,000,000,000
Notes mature installments period one	$ 1,000,000,000		$ 1,000,000,000
Loan Maturing in Three Equal Installments on April 2015, 2016, 2017 [Member] | HNAH [Member] | Senior Notes [Member]
Related Party Transaction [Line Items]
Number of equal installments			3