Related Party Transactions - Summary of Related Party Transactions (Details) - USD ($) $ in Millions		Jun. 30, 2016		Dec. 31, 2015		Jun. 30, 2015	Dec. 31, 2014
Assets:
Cash and due from banks		$ 915		$ 968		$ 1,077	$ 891
Interest bearing deposits with banks		13,799		7,478
Securities purchased under agreements to resell		34,666		19,847
Trading assets		18,812		17,085
Loans		79,810		82,917		83,617
Other assets		9,066		6,890
Total assets		210,873	[1]	188,278	[1]	196,618
Liabilities:
Deposits		132,819		118,579		122,547
Trading liabilities		10,692		7,455
Short-term borrowings		7,376		4,995
Long-term debt		34,778		33,509
Other		4,148		3,215
Total liabilities	[1]	189,813		167,753
Affiliated Entity [Member]
Assets:
Cash and due from banks		172		169
Interest bearing deposits with banks		280		244
Securities purchased under agreements to resell	[2]	4,000		4,000
Trading assets	[3]	19,795		18,632
Loans		5,072		4,815		$ 4,607
Other assets	[4]	229		458
Total assets		29,548		28,318
Liabilities:
Deposits		22,589		13,486
Trading liabilities	[3]	21,632		19,496
Short-term borrowings		2,449		2,004
Long-term debt		1,830		1,827
Other	[4]	274		346
Total liabilities		$ 48,774		$ 37,159

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at June 30, 2016 and December 31, 2015 which are consolidated on our balance sheet. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 17, "Variable Interest Entities," for additional information. Assets: Other assets $280 million and $320 million. Total assets $280 million and $320 million respectively. Liabilities: Long-term debt $92 million and $92 million, Interest, taxes and other liabilities $68 million and $68 million. Total liabilities $160 million and $160 million, respectively.

[2] Reflects overnight purchases of U.S. Treasury securities which HSBC Securities (USA) Inc. ("HSI") has agreed to repurchase.

[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 balances associated with hedging activities and other miscellaneous account receivables and payables.