Related Party Transactions - Summary of Related Party Transactions (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013		Jun. 30, 2013	Dec. 31, 2012
Assets:
Cash and due from banks	$ 2,325		$ 961		$ 1,311	$ 1,359
Interest bearing deposits with banks	23,946		19,614
Trading assets	25,156		28,894
Loans	72,198		67,695		66,705
Other assets	8,321		8,140
Total assets	182,218	[1]	185,487	[1]	189,524
Liabilities:
Deposits	115,521		112,608		111,735
Trading liabilities	8,815		10,875
Short-term borrowings	12,906		19,135
Long-term debt	24,604		22,847
Other	3,388		3,558
Total liabilities	165,234	[1]	169,023	[1]
Parent And Other Subsidiaries Of Common Parent [Member]
Assets:
Cash and due from banks	1,347		102
Interest bearing deposits with banks	1,226	[2]	631	[2]
Trading assets	15,993	[3]	17,082	[3]
Loans	5,080		5,328
Other assets	1,168	[4]	1,219	[4]
Total assets	24,814		24,362
Liabilities:
Deposits	18,676		16,936
Trading liabilities	17,543	[3]	19,463	[3]
Short-term borrowings	1,748		1,514
Long-term debt	3,983		3,987
Other	511	[4]	573	[4]
Total liabilities	$ 42,461		$ 42,473

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") as of June 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, $157 million and $200 million Other assets $458 million and $502 million. Total assets $618 million and $707 million respectively. Liabilities: Long-term debt $92 million and $92 million, Interest, taxes and other liabilities $71 million and $93 million. Total liabilities $163 million and $185 million, respectively.

[2] Includes interest bearing deposits with HSBC Mexico S.A. of $1,100 million and $500 million at June 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.