Related Party Transactions - Summary of Related Party Transactions (Details) - USD ($) $ in Millions		Mar. 31, 2016		Dec. 31, 2015		Mar. 31, 2015		Dec. 31, 2014
Assets:
Cash and due from banks		$ 863		$ 968		$ 972		$ 891
Interest bearing deposits with banks		14,210		7,478
Securities purchased under agreements to resell		25,134		19,847
Trading assets		18,266		17,085
Loans		81,732		82,917		81,458
Other assets		6,853		6,890
Total assets		203,784	[1]	188,278	[1]	201,594
Liabilities:
Deposits		126,303	[2]	118,579		119,094	[2]
Trading liabilities		8,788		7,455
Short-term borrowings		9,897		4,995
Long-term debt		34,525		33,509
Other		3,375		3,215
Total liabilities	[1]	182,888		167,753
Affiliated Entity [Member]
Assets:
Cash and due from banks		149		169
Interest bearing deposits with banks		188		244
Securities purchased under agreements to resell	[3]	4,000		4,000
Trading assets	[4]	19,438		18,632
Loans		5,107		4,815		$ 5,016
Other assets	[5]	205		458
Total assets		29,087		28,318
Liabilities:
Deposits		15,699		13,486
Trading liabilities	[4]	20,754		19,496
Short-term borrowings		2,522		2,004
Long-term debt		1,828		1,827
Other	[5]	295		346
Total liabilities		$ 41,098		$ 37,159

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") as of March 31, 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 $305 million and $320 million. Total assets $305 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] During the second quarter of 2015, we concluded that brokered deposits would be better presented as debt under the Group Reporting Basis. As a result, we reclassified $7.2 billion of brokered deposits in the GB&M segment to debt at March 31, 2015 to conform with the current year presentation.

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

[4] 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.

[5] Other assets and other liabilities primarily consist of derivative balances associated with hedging activities and other miscellaneous account receivables and payables.