Loans - Components of Loans (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 73,439		$ 67,695		$ 67,710
Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	54,062		48,494
Total loans	54,062		48,494
Commercial Loans [Member] | Construction and Other Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	9,661		9,034
Total loans	9,661		9,034		8,919
Commercial Loans [Member] | Business and Corporate Banking [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	17,355		14,446
Total loans	17,355		14,446		13,668
Commercial Loans [Member] | Global Banking [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	24,001	[1]	21,625	[1]
Total loans	24,001		21,625		23,370
Commercial Loans [Member] | Other Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial	3,045		3,389
Total loans	3,045		3,389		2,552
Consumer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer	19,377		19,201
Total loans	19,377		19,201
Consumer Loans [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer	16,402		15,826
Total loans	16,402		15,826		15,720
Consumer Loans [Member] | Home Equity Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer	1,824		2,011
Total loans	1,824		2,011		2,087
Consumer Loans [Member] | Credit Cards [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer	686		854
Total loans	686		854		856
Consumer Loans [Member] | Other consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer	465		510
Total loans	$ 465		$ 510		$ 538

[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 $4,812 million and $5,328 million at September 30, 2014 and December 31, 2013, respectively. See Note 13, "Related Party Transactions" for additional information regarding loans to HSBC affiliates.