Commitments and Contingent Liabilities- Additional Information (Detail) (USD $)	9 Months Ended										0 Months Ended
	Sep. 30, 2014 LegalMatter	Dec. 31, 2013	Jan. 18, 2008	Aug. 31, 2007	Sep. 30, 2014 Standby letters of credit		Dec. 31, 2013 Standby letters of credit		Sep. 30, 2014 Commercial letters of credit	Dec. 31, 2013 Commercial letters of credit	Jun. 25, 2014 Corporate HQ	Sep. 30, 2014 Corporate HQ	Jun. 25, 2014 Corporate HQ sqft	Sep. 30, 2014 Operations	Dec. 31, 2013 Operations
Commitments and Contingencies Disclosure [Line Items]
Lending commitment maturing in less than one year	$ 9,500,000,000
Lending commitment maturing in one to five years	23,300,000,000
Lending commitment maturing over five years	151,000,000
Off Balance Sheet Credit Risk					5,862,000,000	[1]	6,721,000,000	[1]	339,000,000	310,000,000
SBLCs collateralized with cash and securities					642,000,000		418,000,000
SBLCs expiring within one year					3,300,000,000
SBLCs expiring within one to five years					2,600,000,000
Allowance for lending related commitments														97,000,000	134,000,000
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	310,000,000,000	252,000,000,000
Securities Lending Indemnifications Joint Venture	65,000,000,000	60,000,000,000
Securities Lending Indemnifications Collateral Joint Venture	67,000,000,000	64,000,000,000
Area of real estate property (sqft)													350,000
Term of operating lease											20 years
Operating Leases
2015												3,000,000
2016												19,000,000
2017												19,000,000
2018												19,000,000
2019												19,000,000
2020 and Thereafter												313,000,000
Loss contingency, aggregate range of reasonable loss	940,000,000
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	$ 312,000,000
Number of lawsuits pending related to Stanford Matter (legal matters)	4
Number of arbitration claims related to Stanford matter (legal matters)	40

[1] Net of participations totaling $773 million at Sept. 30, 2014 and $720 million at Dec. 31, 2013.