Derivatives and Hedging Activities - Fair Value of Derivative Assets by Type (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 829	$ 1,187	$ 1,331
Less: Related collateral	368	494	513
Total derivative assets	461	693	818
Interest Rate [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	775	1,114	1,221
Foreign Exchange [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	24	23	22
Energy and Commodity [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	28	47	82
Credit [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 2	$ 3	$ 6