Related Party Transactions - Summary of Related Party Transactions (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Assets:
Cash and due from banks	$ 891		$ 961		$ 1,359	$ 1,616
Interest bearing deposits with banks	30,807		19,614
Trading assets	21,092		28,894
Loans	77,741		67,695		63,258
Other assets	7,989		8,140
Total assets	185,539	[1]	185,487	[1]	191,446
Liabilities:
Deposits	116,118		112,608		117,671
Trading liabilities	8,164		10,875
Short-term borrowings	12,795		19,135
Long-term debt	27,524		22,847
Other	3,971		3,558
Total liabilities	168,572	[1]	169,023	[1]
HSBC Mexico [Member]
Assets:
Interest bearing deposits with banks	800		500
Affiliated Entity [Member]
Assets:
Cash and due from banks	140		102
Interest bearing deposits with banks	928	[2]	631	[2]
Trading assets	20,194	[3]	17,082	[3]
Loans	4,821		5,328
Other assets	983	[4]	1,219	[4]
Total assets	27,066		24,362
Liabilities:
Deposits	16,596		16,936
Trading liabilities	21,130	[3]	19,463	[3]
Short-term borrowings	847		1,514
Long-term debt	3,981		3,987
Other	459	[4]	573	[4]
Total liabilities	$ 43,013		$ 42,473

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") as of December 31, 2014 and December 31, 2013 which are consolidated on our balance sheet. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 25, "Variable Interest Entities," for additional information. Assets: Interest bearing deposits with banks, $0 million and $5 million, Securities held-to-maturity, $0 million and $200 million Other assets $380 million and $502 million. Total assets $380 million and $707 million respectively. Liabilities: Long-term debt $92 million and $92 million, Interest, taxes and other liabilities $75 million and $93 million. Total liabilities $167 million and $185 million, respectively.

[2] Includes interest bearing deposits with HSBC Mexico S.A. of $800 million and $500 million at December 31, 2014 and 2013, respectively.

[3] Trading assets and trading liabilities do not reflect the impact of netting which allows the offsetting of amounts relating to certain contracts if certain conditions are met. Trading assets and liabilities primarily consist of derivatives contracts.

[4] Other assets and other liabilities primarily consist of derivative contracts.