Derivatives and Hedging Activities - Fair Values, Volume of Activity and Gain (Loss) Information Related to Derivative Instruments (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Derivatives, Fair Value [Line Items]
Notional Amount	$ 66,737invest_DerivativeNotionalAmount	$ 65,317invest_DerivativeNotionalAmount	$ 66,102invest_DerivativeNotionalAmount
Derivative Assets	585	454	366
Derivative Liabilities	581	543	83
Derivative Asset, Netting adjustments	(1,071)	(1,034)	(713)
Derivative Liability, Netting adjustments	(588)	(542)	(448)
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	17,141	15,466	14,791
Derivative assets	335	280	282
Derivative liabilities	14	26	41
Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	49,596	49,851	51,311
Derivative assets	1,467	1,363	858
Derivative liabilities	1,399	1,300	815
Interest Rate [Member] \| Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	16,802	15,095	14,479
Derivative assets	315	272	277
Derivative liabilities	14	26	40
Interest Rate [Member] \| Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	41,913	43,771	44,156
Derivative assets	728	665	688
Derivative liabilities	678	618	647
Foreign Exchange [Member] \| Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	339	371	312
Derivative assets	20	8	5
Derivative liabilities			1
Foreign Exchange [Member] \| Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	5,544	4,024	4,653
Derivative assets	152	85	55
Derivative liabilities	147	81	51
Commodity [Member] \| Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	1,553	1,544	1,597
Derivative assets	582	608	110
Derivative liabilities	567	594	105
Credit [Member] \| Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	586	512	905
Derivative assets	5	5	5
Derivative liabilities	7	7	12
Net Derivatives [Member]
Derivatives, Fair Value [Line Items]
Notional Amount	66,737	65,317	66,102
Derivative Assets	731	609	427
Derivative Liabilities	825	784	408
Other Collateral [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	(146)	(155)	(61)
Derivative Liabilities	$ (244)	$ (241)	$ (325)

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

Reference 2: http://www.xbrl.org/2003/role/presentationRef

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Topic 210

-SubTopic 20

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Amount of right to receive cash collateral under master netting arrangements offset against derivative liabilities.

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