Commitments and Contingent Liabilities- Additional Information (Detail) (USD $)	Mar. 31, 2013 LegalMatter	Dec. 31, 2012	Jan. 18, 2008	Dec. 21, 2012 Class Actions and Non Class Actions Lawsuits	Oct. 12, 2012 Ivy Asset Management LLC	Nov. 13, 2012 Ivy Asset Management LLC Civil Lawsuits	Mar. 31, 2013 Securities lending indemnifications	Dec. 31, 2012 Securities lending indemnifications	Mar. 31, 2013 Standby letters of credit	Dec. 31, 2012 Standby letters of credit
Commitments and Contingencies Disclosure [Line Items]
Lending commitment maturing in less than one year	$ 9,200,000,000
Lending commitment maturing in one to five years	21,900,000,000
Lending commitment maturing over five years	400,000,000
Potential exposure of off-balance sheet credit risks	175,000,000						251,977,000,000	245,717,000,000	7,129,000,000	7,167,000,000
SBLCs collateralized with cash and securities									677,000,000	781,000,000
SBLCs expiring within one year									3,900,000,000
SBLCs expiring within one to five years										3,200,000,000
Allowance for lending related commitments	121,000,000	121,000,000
Maximum maturities of prearranged contract for a securities lending transaction (in days)	90 days	90 days
Cash collateralization percentage generally required for a securities lending transaction with indemnification against broker default	102.00%	102.00%
Securities lending indemnifications, secured amount of collateral	259,000,000,000	253,000,000,000
Loss Contingency, Range of Possible Loss, Maximum	0
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
Litigation settlement agreement				$ 114,000,000	$ 2,000,000	$ 210,000,000
Number of court actions that most of the Madoff cases have been consolidated into	2