Derivatives and Hedging Activities - Fair Values, Volume of Activity and Gain (Loss) Information Related to Derivative Instruments (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Notional Amount	$ 88,288,000,000	$ 71,424,000,000
Derivative assets, Netting adjustments	(431,000,000)	(866,000,000)
Derivative assets, Fair Value	782,000,000	528,000,000
Derivative liabilities, Netting adjustments	(384,000,000)	(494,000,000)
Derivative liabilities, Fair Value	539,000,000	428,000,000
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	24,519,000,000	19,229,000,000
Derivative assets, Fair Value	195,000,000	277,000,000
Derivative liabilities, Fair Value	98,000,000	15,000,000
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	63,769,000,000	52,195,000,000
Derivative assets, Fair Value	1,039,000,000	1,208,000,000
Derivative liabilities, Fair Value	922,000,000	1,111,000,000
Interest Rate [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	24,237,000,000	18,917,000,000
Derivative assets, Fair Value	189,000,000	257,000,000
Derivative liabilities, Fair Value	94,000,000	15,000,000
Interest Rate [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	55,315,000,000	43,965,000,000
Derivative assets, Fair Value	741,000,000	627,000,000
Derivative liabilities, Fair Value	643,000,000	548,000,000
Foreign Exchange [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	282,000,000	312,000,000
Derivative assets, Fair Value	6,000,000	20,000,000
Derivative liabilities, Fair Value	4,000,000	0
Foreign Exchange [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	6,230,000,000	6,454,000,000
Derivative assets, Fair Value	117,000,000	131,000,000
Derivative liabilities, Fair Value	109,000,000	124,000,000
Commodity [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	1,474,000,000	1,144,000,000
Derivative assets, Fair Value	176,000,000	444,000,000
Derivative liabilities, Fair Value	165,000,000	433,000,000
Credit [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	360,000,000	632,000,000
Derivative assets, Fair Value	1,000,000	6,000,000
Derivative liabilities, Fair Value	4,000,000	6,000,000
Other Credit Derivatives [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	390,000,000	0
Derivative assets, Fair Value	4,000,000	0
Derivative liabilities, Fair Value	1,000,000	0
Net Derivatives [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	88,288,000,000	71,424,000,000
Derivative assets, Fair Value	803,000,000	619,000,000
Derivative liabilities, Fair Value	636,000,000	632,000,000
Counterparty And Cash Collateral Netting [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	0	0
Derivative assets, Fair Value	(21,000,000)	(91,000,000)
Derivative liabilities, Fair Value	$ (97,000,000)	$ (204,000,000)