Related Party Transactions - Summary of Related Party Transactions (Income - Expense) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Related Party Transaction [Line Items]
Interest income									$ 2,979		$ 3,206		$ 3,428
Interest expense									(938)		(1,048)		(994)
Net interest income (loss)	526	492	518	505	526	510	535	587	2,041	[1]	2,158	[1]	2,434
Servicing and other fees with HSBC affiliates:
Total affiliate income									202		202		202
Support services from HSBC affiliates:
Total support services from HSBC affiliates									(1,459)		(1,480)		(1,513)
Parent And Other Subsidiaries Of Common Parent [Member]
Related Party Transaction [Line Items]
Interest income									232		193		128
Interest expense									(78)		(91)		(82)
Net interest income (loss)									154		102		46
Servicing and other fees with HSBC affiliates:
Residential mortgage banking revenue									0		3		17
Support services from HSBC affiliates:
Stock based compensation expense with HSBC									(34)	[2]	(36)	[2]	(56)	[2]
Hsbc Finance And Other Hsbc Affiliates [Member]
Servicing and other fees with HSBC affiliates:
Total affiliate income									202		202		202
Support services from HSBC affiliates:
Total support services from HSBC affiliates									(1,459)		(1,480)		(1,513)
HSBC Finance Corporation [Member]
Servicing and other fees with HSBC affiliates:
Total affiliate income									86		72		65
Support services from HSBC affiliates:
Total support services from HSBC affiliates									(14)		(27)		(36)
HSBC Markets (USA) Inc. (HMUS) and subsidiaries [Member]
Servicing and other fees with HSBC affiliates:
Total affiliate income									17		18		23
Support services from HSBC affiliates:
Total support services from HSBC affiliates									(228)		(326)		(275)
Other HSBC Affiliates [Member]
Servicing and other fees with HSBC affiliates:
Total affiliate income									51		74		79
Support services from HSBC affiliates:
Total support services from HSBC affiliates									(217)		(215)		(235)
Other HSBC Affiliates Income [Member]
Servicing and other fees with HSBC affiliates:
Total affiliate income									48		38		35
HSBC Technology and Services (USA) (HTSU) [Member]
Support services from HSBC affiliates:
Total support services from HSBC affiliates									$ (1,000)		$ (912)		$ (967)

[1] Net interest income of each segment represents the difference between actual interest earned on assets and interest paid on liabilities of the segment adjusted for a funding charge or credit. Segments are charged a cost to fund assets (e.g. customer loans) and receive a funding credit for funds provided (e.g. customer deposits) based on equivalent market rates. The objective of these charges/credits is to transfer interest rate risk from the segments to one centralized unit in Treasury and more appropriately reflect the profitability of segments.

[2] Employees may participate in one or more stock compensation plans sponsored by HSBC. These expenses are included in Salaries and employee benefits in our consolidated statement of income (loss). Employees also may participate in a defined benefit pension plan and other postretirement plans sponsored by HSBC North America which are discussed in Note 21, "Pension and Other Postretirement Benefits."