Related Party Transactions - Summary of Related Party Transactions (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2013	Dec. 31, 2012
Assets:
Cash and due from banks	$ 1,013		$ 961		$ 1,512	$ 1,359
Interest bearing deposits with banks	26,379		19,614
Trading assets	22,099		28,894
Loans	73,439		67,695		67,710
Other assets	7,349		8,140
Total assets	175,012	[1]	185,487	[1]	187,375
Liabilities:
Deposits	108,677		112,608		112,921
Trading liabilities	9,177		10,875
Short-term borrowings	11,864		19,135
Long-term debt	25,034		22,847
Other	3,377		3,558
Total liabilities	158,129	[1]	169,023	[1]
HSBC Mexico [Member]
Assets:
Interest bearing deposits with banks	800		500
Affiliated Entity [Member]
Assets:
Cash and due from banks	159		102
Interest bearing deposits with banks	960	[2]	631	[2]
Trading assets	17,908	[3]	17,082	[3]
Loans	4,812		5,328
Other assets	1,359	[4]	1,219	[4]
Total assets	25,198		24,362
Liabilities:
Deposits	12,672		16,936
Trading liabilities	18,670	[3]	19,463	[3]
Short-term borrowings	504		1,514
Long-term debt	3,984		3,987
Other	598	[4]	573	[4]
Total liabilities	$ 36,428		$ 42,473

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") as of September 30, 2014 and December 31, 2013 which are consolidated on our balance sheet. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 16, "Variable Interest Entities," for additional information. Assets: Interest bearing deposits with banks, $3 million and $5 million, Securities held-to-maturity, $76 million and $200 million Other assets $436 million and $502 million. Total assets $515 million and $707 million respectively. Liabilities: Long-term debt $92 million and $92 million, Interest, taxes and other liabilities $81 million and $93 million. Total liabilities $173 million and $185 million, respectively.

[2] Includes interest bearing deposits with HSBC Mexico S.A. of $800 million and $500 million at September 30, 2014 and December 31, 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.