Trading Assets and Liabilities and Derivatives(Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	$ 6,202	[1]	$ 5,040	[1]
Trading liabilities	1,227		1,181
US Treasury Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	267		219
Trading liabilities	485		472
US Government Agencies Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	547		426
US States and Political Subdivisions Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	42		65
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	545		323
Trading liabilities	1		0
Corporate Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	509		534
Trading liabilities	279		179
Collateralized Debt Obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	3		57
Asset-backed Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	0		6
Commercial Paper [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	327		29
Equity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	45		109
Trading liabilities	0		5
Derivative Financial Instruments, Assets
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	1,307	[2]	1,384	[2]
Loans
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading assets	2,610	[3]	1,888	[3]
Derivative Financial Instruments, Liabilities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Trading liabilities	$ 462	[2]	$ 525	[2]

[1] Includes loans held for sale, at fair value, of consolidated VIEs of $0 million and $261 million at December 31, 2014 and December 31, 2013, 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.