Related Party Transactions (Details Textual) (USD $)	3 Months Ended		6 Months Ended				3 Months Ended		6 Months Ended			6 Months Ended	12 Months Ended						3 Months Ended	6 Months Ended			3 Months Ended		6 Months Ended		12 Months Ended	1 Months Ended		3 Months Ended		6 Months Ended					3 Months Ended		6 Months Ended			6 Months Ended					3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011		Jun. 30, 2012 HSBC Finance [Member]	Jun. 30, 2011 HSBC Finance [Member]	Jun. 30, 2012 HSBC Finance [Member]	Jun. 30, 2011 HSBC Finance [Member]	Dec. 31, 2011 HSBC Finance [Member]	Jun. 30, 2012 HSBC Finance [Member] Extended uncommitted revolving credit facility [Member]	Dec. 31, 2011 HSBC Finance [Member] Extended uncommitted revolving credit facility [Member]	Jun. 30, 2012 HSBC Finance [Member] Extended committed revolving credit facility [Member]	May 31, 2012 HSBC Finance [Member] Extended committed revolving credit facility [Member]	Dec. 31, 2011 HSBC Finance [Member] Extended committed revolving credit facility [Member]	Jun. 30, 2012 HSBC Finance [Member] Credit Card Customer Relationship [Member]	Mar. 29, 2012 HSBC Finance [Member] Credit Card Customer Relationship [Member]	Jun. 30, 2011 HSBC Finance [Member] Credit Card Receivable [Member]	Jun. 30, 2012 HSBC Finance [Member] Credit Card Receivable [Member]	Jun. 30, 2011 HSBC Finance [Member] Credit Card Receivable [Member]	Dec. 31, 2011 HSBC Finance [Member] Credit Card Receivable [Member]	Jun. 30, 2012 HMUS [Member]	Jun. 30, 2011 HMUS [Member]	Jun. 30, 2012 HMUS [Member]	Jun. 30, 2011 HMUS [Member]	Dec. 31, 2011 HMUS [Member]	Jan. 31, 2011 Halbis Capital Management USA [Member]	Apr. 30, 2011 Halbis Capital Management USA [Member] European Banknotes Business [Member]	Jun. 30, 2012 HNAH [Member]	Jun. 30, 2011 HNAH [Member]	Jun. 30, 2012 HNAH [Member]	Jun. 30, 2011 HNAH [Member]	Dec. 31, 2011 HNAH [Member]	Apr. 30, 2011 HNAH [Member]	Aug. 31, 2009 HNAH [Member]	Jun. 30, 2012 Other Affiliates [Member]	Jun. 30, 2011 Other Affiliates [Member]	Jun. 30, 2012 Other Affiliates [Member]	Jun. 30, 2011 Other Affiliates [Member]	Dec. 31, 2011 Other Affiliates [Member]	Jun. 30, 2012 HSBC France [Member]	Dec. 31, 2011 HSBC France [Member]	Dec. 31, 2011 HSBC North America Inc. [Member]	Jun. 30, 2012 HSBC Finance and other HSBC Affiliates [Member]	Dec. 31, 2011 HSBC Finance and other HSBC Affiliates [Member]	Jun. 30, 2012 HSBC Global Resourcing [Member]	Jun. 30, 2011 HSBC Global Resourcing [Member]	Jun. 30, 2012 HSBC Global Resourcing [Member]	Jun. 30, 2011 HSBC Global Resourcing [Member]	Jun. 30, 2012 Residential Mortgage [Member]	Dec. 31, 2011 Residential Mortgage [Member]
Related Party Transactions (Textual) [Abstract]
Credit card receivables																	$ 970,000,000	$ 108,000,000
Credit card servicing																						1,200,000,000
Fee for servicing credit cards							2,000,000	4,000,000	7,000,000	8,000,000
Residential mortgage loans servicing																																																			1,300,000,000	1,300,000,000
Credit card receivables purchased							2,500,000,000	8,100,000,000	9,900,000,000	15,500,000,000									600,000,000	500,000,000	1,100,000,000
Residential mortgage loans servicing fees							1,000,000	1,000,000	2,000,000	2,000,000
Services fee paid							1,000,000	1,000,000	3,000,000	3,000,000
Services fee received							1,000,000	2,000,000	3,000,000	4,000,000
Service Revenue received against employee work for main bank							14,000,000		28,000,000
Service Revenue received against employee work for main bank last year								15,000,000		32,000,000
Extended secured uncommitted credit facility and loans and lines of credit									1,500,000,000																2,800,000,000		2,800,000,000
Extended secured uncommitted credit facility to certain subsidiary (In days)									364 days
Loans and lines of credit amount outstanding																							317,000,000		317,000,000		229,000,000
Loans and lines of credit amount outstanding							0		0		0	0	0	0		0
Extended line of credit													3,000,000,000		2,000,000,000
Extended unsecured uncommitted credit facility to certain subsidiary maturity													15 years
Amendment for increase extended unsecured uncommitted credit facility to certain subsidiary												4,000,000,000
Line of Credit							1,000,000,000		1,000,000,000
Line of credit amount outstanding							0		0		0																										0		0		0
Purchase of Portfolios with an outstanding principal									12,400,000,000
Fees paid for servicing of components of income from discontinued operation							48,000,000	151,000,000	199,000,000	297,000,000
Extended line of credit							1,000,000,000		1,000,000,000
Extended line of credit amount outstanding							0		0		0
Increase in additional paid-in-capital																												21,000,000
Senior notes																																			3,000,000,000	1,000,000,000
Notes mature installments period one																														1,000,000,000		1,000,000,000
Senior note floating rate period																																5 years
Notes mature installments period two																														1,000,000,000		1,000,000,000
Notes mature installments period three																														1,000,000,000		1,000,000,000
Senior note interest rate description																																notes bear interest at 90 day USD Libor plus a spread
Senior note interest rate period																																90 days
Interest expense on notes																														17,000,000	13,000,000	33,000,000	17,000,000
Marketable securities																														1,300,000,000		1,300,000,000		8,500,000,000
Notional value of credit derivatives transactions	571,000,000,000		571,000,000,000		657,300,000,000																																48,000,000,000		48,000,000,000		45,100,000,000
Derivative Liabilities																																					1,600,000,000		1,600,000,000		1,000,000,000
Loan and lease receivable unused line of credit facility																																										2,500,000,000	2,500,000,000	150,000,000
Loan and Lease Receivable Unused Line of Credit Facility Termination Date																																										Jul. 30, 2012
Extended loans and lines of credit																																					460,000,000		460,000,000		460,000,000
Loans and lines of credit interest income																							1,000,000	2,000,000	2,000,000	4,000,000
Loans and lines of credit interest income																																					0			0
Notional value of interest rate derivative	3,014,300,000,000		3,014,300,000,000		2,782,600,000,000																																								960,300,000,000	887,100,000,000
Fair value of derivative receivables																																													22,600,000,000	22,400,000,000
Expense of stock compensation plans on a pre-tax basis	8,000,000	15,000,000	20,000,000	24,000,000																																	8,000,000	15,000,000	20,000,000	24,000,000
Support services expense																																															6,000,000		13,000,000
Prior year professional and contract services expense																																																7,000,000		13,000,000
Sale of our European Banknotes Business with assets					21,454,000,000	[1]																							123,000,000
Services fee received							1,000,000	2,000,000	3,000,000	4,000,000
Loans and lines of credit interest income																							1,000,000	2,000,000	2,000,000	4,000,000
Increase in additional paid-in-capital																												21,000,000
Marketable securities																														1,300,000,000		1,300,000,000		8,500,000,000
Derivative Liabilities																																					1,600,000,000		1,600,000,000		1,000,000,000
Loan and lease receivable unused line of credit facility																																										2,500,000,000	2,500,000,000	150,000,000
Extended loans and lines of credit																																					460,000,000		460,000,000		460,000,000
Fair value of derivative receivables																																													22,600,000,000	22,400,000,000
Expense of stock compensation plans on a pre-tax basis	8,000,000	15,000,000	20,000,000	24,000,000																																	8,000,000	15,000,000	20,000,000	24,000,000
Support services expense																																															6,000,000		13,000,000
Prior year professional and contract services expense																																																7,000,000		13,000,000
Related Party Transaction (Additional Textual) [Abstract]
Residential mortgage loans purchased			3,700,000,000
Net premium of outstanding principal			$ 113,000,000

[1] The following table summarizes assets and liabilities related to variable interest entities ("VIEs") as of June 30, 2012 and December 31, 2011 which are consolidated on our balance sheet. Assets and liabilities exclude intercompany balances that eliminate in consolidation.