Derivatives and Hedging Activities - Fair Value of Derivative Assets by Type (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 958	$ 996
Less: Related collateral	155	377
Total derivative assets	803	619
Interest Rate [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	782	628
Foreign Exchange [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	62	66
Commodity [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	110	298
Credit [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	0	4
Other Credit Derivatives [Member]
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 4	$ 0