Fair Value Measurement - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Securities available for sale:
Securities available for sale	$ 39,061	$ 39,508
Other assets:
Consumer MSRs	68	53
Derivative Assets, Gross Amount	1,518	1,452
Liabilities:
Derivative Liabilities, Gross Amount	520	339
Derivative Liabilities	377	175
Derivative Asset	986	828
Derivative Credit Risk Valuation Adjustment, Derivative Assets (Liabilities)	4	4
Fair Value, Measurements, Recurring [Member]
Securities available for sale:
Securities available for sale	39,061	39,508
Other assets:
Consumer MSRs	68	53
Derivative Assets, Gross Amount	1,518	1,452
Retained interests in securitizations	211	221
Total assets	40,858	41,234
Liabilities:
Derivative Liabilities, Gross Amount	520	339
Total liabilities	520	339
Fair Value, Measurements, Recurring [Member] \| Level 1
Securities available for sale:
Securities available for sale	5,015	4,228
Other assets:
Consumer MSRs	0	0
Derivative Assets, Gross Amount	2	4
Retained interests in securitizations	0	0
Total assets	5,017	4,232
Liabilities:
Derivative Liabilities, Gross Amount	2	3
Total liabilities	2	3
Fair Value, Measurements, Recurring [Member] \| Level 2
Securities available for sale:
Securities available for sale	33,431	34,075
Other assets:
Consumer MSRs	0	0
Derivative Assets, Gross Amount	1,459	1,382
Retained interests in securitizations	0	0
Total assets	34,890	35,457
Liabilities:
Derivative Liabilities, Gross Amount	491	293
Total liabilities	491	293
Fair Value, Measurements, Recurring [Member] \| Level 3
Securities available for sale:
Securities available for sale	615	1,205
Other assets:
Consumer MSRs	68	53
Derivative Assets, Gross Amount	57	66
Retained interests in securitizations	211	221
Total assets	951	1,545
Liabilities:
Derivative Liabilities, Gross Amount	27	43
Total liabilities	27	43
US Treasury securities \| Fair Value, Measurements, Recurring [Member]
Securities available for sale:
Securities available for sale	4,660	4,118
US Treasury securities \| Fair Value, Measurements, Recurring [Member] \| Level 1
Securities available for sale:
Securities available for sale	4,660	4,117
US Treasury securities \| Fair Value, Measurements, Recurring [Member] \| Level 2
Securities available for sale:
Securities available for sale	0	1
US Treasury securities \| Fair Value, Measurements, Recurring [Member] \| Level 3
Securities available for sale:
Securities available for sale	0	0
Corporate debt securities guaranteed by U.S. government agencies \| Fair Value, Measurements, Recurring [Member]
Securities available for sale:
Securities available for sale		800
Corporate debt securities guaranteed by U.S. government agencies \| Fair Value, Measurements, Recurring [Member] \| Level 1
Securities available for sale:
Securities available for sale		0
Corporate debt securities guaranteed by U.S. government agencies \| Fair Value, Measurements, Recurring [Member] \| Level 2
Securities available for sale:
Securities available for sale		467
Corporate debt securities guaranteed by U.S. government agencies \| Fair Value, Measurements, Recurring [Member] \| Level 3
Securities available for sale:
Securities available for sale		333
RMBS \| Fair Value, Measurements, Recurring [Member]
Securities available for sale:
Securities available for sale	27,311	25,381
RMBS \| Fair Value, Measurements, Recurring [Member] \| Level 1
Securities available for sale:
Securities available for sale	0	0
RMBS \| Fair Value, Measurements, Recurring [Member] \| Level 2
Securities available for sale:
Securities available for sale	26,807	24,820
RMBS \| Fair Value, Measurements, Recurring [Member] \| Level 3
Securities available for sale:
Securities available for sale	504	561
CMBS \| Fair Value, Measurements, Recurring [Member]
Securities available for sale:
Securities available for sale	5,379	5,519
CMBS \| Fair Value, Measurements, Recurring [Member] \| Level 1
Securities available for sale:
Securities available for sale	0	0
CMBS \| Fair Value, Measurements, Recurring [Member] \| Level 2
Securities available for sale:
Securities available for sale	5,282	5,291
CMBS \| Fair Value, Measurements, Recurring [Member] \| Level 3
Securities available for sale:
Securities available for sale	97	228
Other ABS \| Fair Value, Measurements, Recurring [Member]
Securities available for sale:
Securities available for sale	1,340	2,662
Other ABS \| Fair Value, Measurements, Recurring [Member] \| Level 1
Securities available for sale:
Securities available for sale	0	0
Other ABS \| Fair Value, Measurements, Recurring [Member] \| Level 2
Securities available for sale:
Securities available for sale	1,340	2,597
Other ABS \| Fair Value, Measurements, Recurring [Member] \| Level 3
Securities available for sale:
Securities available for sale	0	65
Other securities \| Fair Value, Measurements, Recurring [Member]
Securities available for sale:
Securities available for sale	371	1,028
Other securities \| Fair Value, Measurements, Recurring [Member] \| Level 1
Securities available for sale:
Securities available for sale	355	111
Other securities \| Fair Value, Measurements, Recurring [Member] \| Level 2
Securities available for sale:
Securities available for sale	2	899
Other securities \| Fair Value, Measurements, Recurring [Member] \| Level 3
Securities available for sale:
Securities available for sale	$ 14	$ 18

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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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Fair value, before 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 elected not 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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