Trading Assets and Liabilities and Derivatives(Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	$ 6,595	[1]	$ 6,202	[1]
Trading liabilities	1,459		1,227
US Treasury Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	451		267
Trading liabilities	614		485
US Government Agencies Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	327		547
Trading liabilities	2		0
US States and Political Subdivisions Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	100		42
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	575		545
Trading liabilities	3		1
Collateralized Loan Obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	3		3
Corporate Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	646		509
Trading liabilities	288		279
Commercial Paper [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	239		327
Equity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	46		45
Derivative Financial Instruments, Assets
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	1,475	[2]	1,307	[2]
Loans
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	2,733	[3]	2,610	[3]
Derivative Financial Instruments, Liabilities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities	$ 552	[2]	$ 462	[2]

[1] Includes trading securities pledged as collateral where counterparties have the right to sell or repledge the collateral of $1,207 million and $1,316 million at March 31, 2015 and December 31, 2014, respectively

[2] 1 Amounts include the impact of offsetting cash collateral received from and paid to the same derivative counterparties and the impact of netting derivative assets and derivative liabilities when a legally enforceable master netting agreement or similar agreement exists.

[3] 2 Includes loans related to TRS.