Derivatives and Hedging Activities - Fair Values, Volume of Activity and Gain (Loss) Information Related to Derivative Instruments (Detail) - USD ($)	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Derivatives, Fair Value [Line Items]
Notional Amount	$ 75,475,000,000	$ 71,424,000,000	$ 71,252,000,000
Derivative Assets	1,186,000,000	528,000,000	440,000,000
Derivative Liabilities	534,000,000	428,000,000	344,000,000
Derivative Assets, Netting adjustments	(660,000,000)	(866,000,000)	(834,000,000)
Derivative Liabilities, Netting adjustments	(484,000,000)	(494,000,000)	(486,000,000)
Derivative Assets	(48,000,000)	(91,000,000)	(96,000,000)
Derivative Liabilities	(212,000,000)	(204,000,000)	(216,000,000)
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	23,043,000,000	19,229,000,000	17,657,000,000
Derivative assets	580,000,000	277,000,000	284,000,000
Derivative liabilities	26,000,000	15,000,000	26,000,000
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	52,432,000,000	52,195,000,000	53,595,000,000
Derivative assets	1,314,000,000	1,208,000,000	1,086,000,000
Derivative liabilities	1,204,000,000	1,111,000,000	1,020,000,000
Interest Rate [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	22,754,000,000	18,917,000,000	17,324,000,000
Derivative assets	572,000,000	257,000,000	267,000,000
Derivative liabilities	13,000,000	15,000,000	22,000,000
Interest Rate [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	44,498,000,000	43,965,000,000	45,067,000,000
Derivative assets	990,000,000	627,000,000	589,000,000
Derivative liabilities	899,000,000	548,000,000	546,000,000
Foreign Exchange [Member] | Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	289,000,000	312,000,000	333,000,000
Derivative assets	8,000,000	20,000,000	17,000,000
Derivative liabilities	13,000,000		4,000,000
Foreign Exchange [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	6,148,000,000	6,454,000,000	6,486,000,000
Derivative assets	107,000,000	131,000,000	114,000,000
Derivative liabilities	100,000,000	124,000,000	104,000,000
Commodity [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	1,319,000,000	1,144,000,000	1,537,000,000
Derivative assets	213,000,000	444,000,000	379,000,000
Derivative liabilities	201,000,000	433,000,000	365,000,000
Credit [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	467,000,000	632,000,000	505,000,000
Derivative assets	4,000,000	6,000,000	4,000,000
Derivative liabilities	4,000,000	6,000,000	5,000,000
Net Derivatives [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	75,475,000,000	71,424,000,000	71,252,000,000
Derivative Assets	1,234,000,000	619,000,000	536,000,000
Derivative Liabilities	746,000,000	632,000,000	560,000,000
Counterparty and Cash Collateral Netting [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	(48,000,000)	(91,000,000)	(96,000,000)
Derivative Liabilities	$ (212,000,000)	$ (204,000,000)	$ (216,000,000)