Commitments and Contingent Liabilities- Additional Information (Detail)	0 Months Ended	3 Months Ended														0 Months Ended
	Mar. 19, 2015 USD ($)	Mar. 31, 2015 USD ($) LegalMatter	Mar. 02, 2015 LegalMatter	Dec. 31, 2014 USD ($)	Nov. 03, 2014 panel	Jan. 18, 2008 USD ($)	Mar. 19, 2015 Foreign Exchange Matters LegalMatter	Mar. 31, 2015 Standby letters of credit USD ($)		Dec. 31, 2014 Standby letters of credit USD ($)		Mar. 31, 2015 Commercial letters of credit USD ($)	Dec. 31, 2014 Commercial letters of credit USD ($)	Mar. 31, 2015 Operations USD ($)	Dec. 31, 2014 Operations USD ($)	Mar. 19, 2015 DOJ and NYAG settlements USD ($)	Mar. 19, 2015 Class Action Settlement USD ($)	Mar. 19, 2015 DOL Settlement USD ($)	Mar. 19, 2015 SEC Penalty USD ($)	Apr. 15, 2015 Subsequent Event UK Financial Conduct Authority Matter GBP (£)
Commitments and Contingencies Disclosure [Line Items]
Lending commitment maturing in less than one year		$ 11,300,000,000
Lending commitment maturing in one to five years		22,600,000,000
Lending commitment maturing over five years		252,000,000
SBLCs collateralized with cash and securities								412,000,000		421,000,000
SBLCs expiring within one year								3,400,000,000
SBLCs expiring within one to five years								2,200,000,000
Allowance for lending related commitments														93,000,000	89,000,000
Off balance sheet credit risk								5,600,000,000	[1]	5,767,000,000	[1]	264,000,000	255,000,000
Maximum maturities of prearranged contract for a securities lending transaction (in days)		90 days
Cash collateralization percentage generally required for a securities lending transaction with indemnification against broker default (percent)		102.00%
Securities lending indemnifications, secured amount of collateral		323,000,000,000		316,000,000,000
Securities lending indemnifications joint venture		68,000,000,000		64,000,000,000
Securities Lending Indemnifications Collateral Joint Venture		72,000,000,000		67,000,000,000
Loss contingency, aggregate range of reasonable loss		280,000,000
Bank filed a proof of claim on Jan. 18, 2008 in the Chapter 11 bankruptcy of Sentinel Management Group, Inc. (Sentinel), seeking to recover approximate amount loaned to Sentinel						312,000,000
FX-related settlements	714,000,000															167,500,000	335,000,000	14,000,000	30,000,000
Number of pending lawsuits							2
Number of lawsuits pending related to Stanford Matter (legal matters)		11
Number of FINRA arbitration panels					2
Number of arbitration claims related to Stanford matter settled			38
Arbitration claims related to Stanford matter pending			6
Litigation settlement amount																				£ 126,000,000

[1] Net of participations totaling $961 million at March 31, 2015 and $894 million at Dec. 31, 2014.