Derivatives and Hedging Activities - Fair Value of Derivative Assets by Type (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 1,049	$ 1,187	$ 1,280
Less: Related collateral	440	494	450
Total derivative assets	609	693	830
Interest Rate [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	984	1,114	1,117
Foreign exchange [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	18	23	34
Energy and Commodity [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	45	47	121
Credit [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	2	3	6
Equity [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral			$ 2