Loans - Components of Loans (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013		Mar. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 68,897		$ 67,695		$ 62,932
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	49,893		48,494
Total loans	49,893		48,494
Commercial Loan [Member] | Construction and Other Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	9,165		9,034
Total loans	9,165		9,034		8,319
Commercial Loan [Member] | Business and Corporate Banking [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	15,698		14,446
Total loans	15,698		14,446		12,725
Commercial Loan [Member] | Global Banking [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	21,979	[1]	21,625	[1]
Total loans	21,979		21,625		19,718
Commercial Loan [Member] | Other Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	3,051		3,389
Total loans	3,051		3,389		2,877
Consumer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer	19,004		19,201
Total loans	19,004		19,201
Consumer Loans [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer	15,900		15,826
Total loans	15,900		15,826		15,730
Consumer Loans [Member] | Home Equity Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer	1,938		2,011
Total loans	1,938		2,011		2,236
Consumer Loans [Member] | Credit Cards [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer	683		854
Total loans	683		854		749
Consumer Loans [Member] | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer	483		510
Total loans	$ 483		$ 510		$ 578

[1] Represents large multinational firms including globally focused U.S. corporate and financial institutions and U.S. Dollar lending to multinational banking customers managed by HSBC on a global basis. Also includes loans to HSBC affiliates which totaled $5,277 million and $5,328 million at March 31, 2014 and December 31, 2013, respectively. See Note 13, "Related Party Transactions" for additional information regarding loans to HSBC affiliates.