Derivatives and Hedging Activities - Fair Value of Derivative Assets by Type (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 1,245	$ 1,127	$ 697
Less: Related collateral	514	518	270
Total derivative assets	731	609	427
Interest Rate [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	755	607	606
Foreign Exchange [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	58	41	20
Commodity [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	431	478	72
Credit [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 1	$ 1	$ (1)