Fair Value of Financial Instruments - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Securities available for sale:
Securities available for sale	$ 39,665	$ 41,800
Other assets:
Consumer MSRs	58	73
Derivative assets	836	959
Liabilities
Derivative liabilities	369	710
Cumulative credit risk valuation adjustment related to derivative positions	3	1
U.S. Treasury debt obligations
Securities available for sale:
Securities available for sale	4,261	833
U.S. agency debt obligations
Securities available for sale:
Securities available for sale	1	1
Corporate debt securities guaranteed by U.S. government agencies
Securities available for sale:
Securities available for sale	979	1,234
RMBS
Securities available for sale:
Securities available for sale	24,483	25,079
CMBS
Securities available for sale:
Securities available for sale	5,786	6,006
Other ABS
Securities available for sale:
Securities available for sale	3,083	7,136
Other securities
Securities available for sale:
Securities available for sale	1,072	1,511
Level 1
Securities available for sale:
Securities available for sale	4,373	960
Other assets:
Derivative assets	0	3
Retained interests in securitizations	0	0
Liabilities
Derivative liabilities	1	4
Level 2
Securities available for sale:
Securities available for sale	33,826	37,510
Other assets:
Derivative assets	785	906
Retained interests in securitizations	0	0
Liabilities
Derivative liabilities	329	668
Level 3
Securities available for sale:
Securities available for sale	1,466	3,330
Other assets:
Derivative assets	51	50
Retained interests in securitizations	203	199
Liabilities
Derivative liabilities	39	38
Recurring
Securities available for sale:
Securities available for sale	39,665	41,800
Other assets:
Consumer MSRs	58	73
Derivative assets	836	959
Retained interests in securitizations	203	199
Total assets	40,762	43,031
Liabilities
Derivative liabilities	369	710
Total liabilities	369	710
Recurring \| U.S. Treasury debt obligations
Securities available for sale:
Securities available for sale	4,261	833
Recurring \| U.S. agency debt obligations
Securities available for sale:
Securities available for sale	1	1
Recurring \| Corporate debt securities guaranteed by U.S. government agencies
Securities available for sale:
Securities available for sale	979	1,234
Recurring \| RMBS
Securities available for sale:
Securities available for sale	24,483	25,079
Recurring \| CMBS
Securities available for sale:
Securities available for sale	5,786	6,006
Recurring \| Other ABS
Securities available for sale:
Securities available for sale	3,083	7,136
Recurring \| Other securities
Securities available for sale:
Securities available for sale	1,072	1,511
Recurring \| Level 1
Securities available for sale:
Securities available for sale	4,373	960
Other assets:
Consumer MSRs	0	0
Derivative assets	0	3
Retained interests in securitizations	0	0
Total assets	4,373	963
Liabilities
Derivative liabilities	1	4
Total liabilities	1	4
Recurring \| Level 1 \| U.S. Treasury debt obligations
Securities available for sale:
Securities available for sale	4,261	833
Recurring \| Level 1 \| U.S. agency debt obligations
Securities available for sale:
Securities available for sale	0	0
Recurring \| Level 1 \| Corporate debt securities guaranteed by U.S. government agencies
Securities available for sale:
Securities available for sale	0	0
Recurring \| Level 1 \| RMBS
Securities available for sale:
Securities available for sale	0	0
Recurring \| Level 1 \| CMBS
Securities available for sale:
Securities available for sale	0	0
Recurring \| Level 1 \| Other ABS
Securities available for sale:
Securities available for sale	0	0
Recurring \| Level 1 \| Other securities
Securities available for sale:
Securities available for sale	112	127
Recurring \| Level 2
Securities available for sale:
Securities available for sale	33,826	37,510
Other assets:
Consumer MSRs	0	4
Derivative assets	785	906
Retained interests in securitizations	0	0
Total assets	34,611	38,420
Liabilities
Derivative liabilities	329	668
Total liabilities	329	668
Recurring \| Level 2 \| U.S. Treasury debt obligations
Securities available for sale:
Securities available for sale	0	0
Recurring \| Level 2 \| U.S. agency debt obligations
Securities available for sale:
Securities available for sale	1	1
Recurring \| Level 2 \| Corporate debt securities guaranteed by U.S. government agencies
Securities available for sale:
Securities available for sale	595	307
Recurring \| Level 2 \| RMBS
Securities available for sale:
Securities available for sale	23,826	23,775
Recurring \| Level 2 \| CMBS
Securities available for sale:
Securities available for sale	5,483	5,267
Recurring \| Level 2 \| Other ABS
Securities available for sale:
Securities available for sale	2,973	6,793
Recurring \| Level 2 \| Other securities
Securities available for sale:
Securities available for sale	948	1,367
Recurring \| Level 3
Securities available for sale:
Securities available for sale	1,466	3,330
Other assets:
Consumer MSRs	58	69
Derivative assets	51	50
Retained interests in securitizations	203	199
Total assets	1,778	3,648
Liabilities
Derivative liabilities	39	38
Total liabilities	39	38
Recurring \| Level 3 \| U.S. Treasury debt obligations
Securities available for sale:
Securities available for sale	0	0
Recurring \| Level 3 \| U.S. agency debt obligations
Securities available for sale:
Securities available for sale	0	0
Recurring \| Level 3 \| Corporate debt securities guaranteed by U.S. government agencies
Securities available for sale:
Securities available for sale	384	927
Recurring \| Level 3 \| RMBS
Securities available for sale:
Securities available for sale	657	1,304
Recurring \| Level 3 \| CMBS
Securities available for sale:
Securities available for sale	303	739
Recurring \| Level 3 \| Other ABS
Securities available for sale:
Securities available for sale	110	343
Recurring \| Level 3 \| Other securities
Securities available for sale:
Securities available for sale	$ 12	$ 17

Derivative Credit Risk Valuation Adjustment, Derivative Assets (Liabilities)

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

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Fair value portion of interest continued to be held by a transferor after transferring financial assets to a third party.

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Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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