Fair Value Measurement - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Securities available for sale:
Securities available for sale	$ 40,737	$ 39,061
Other assets:
Derivative Assets, Gross Amount	1,494	1,518
Consumer MSRs	80	68
Liabilities:
Derivative Liabilities, Gross Amount	1,438	520
Derivative Asset	955	986
Derivative Liabilities	1,102	377
Derivative Credit Risk Valuation Adjustment, Derivative Assets (Liabilities)	5	4
Fair Value, Measurements, Recurring [Member]
Securities available for sale:
Securities available for sale	40,737	39,061
Other assets:
Derivative Assets, Gross Amount	1,494	1,518
Other Assets Fair Value, Amount	500	462
Total assets	42,731	41,041
Liabilities:
Derivative Liabilities, Gross Amount	1,438	520
Total liabilities	1,438	520
Fair Value, Measurements, Recurring [Member] \| Level 1
Securities available for sale:
Securities available for sale	5,360	5,015
Other assets:
Derivative Assets, Gross Amount	7	2
Other Assets Fair Value, Amount	219	183
Deferred Compensation Plan Assets	219	183
Total assets	5,586	5,200
Liabilities:
Derivative Liabilities, Gross Amount	12	2
Total liabilities	12	2
Fair Value, Measurements, Recurring [Member] \| Level 2
Securities available for sale:
Securities available for sale	34,799	33,431
Other assets:
Derivative Assets, Gross Amount	1,440	1,459
Other Assets Fair Value, Amount	0	0
Total assets	36,239	34,890
Liabilities:
Derivative Liabilities, Gross Amount	1,397	491
Total liabilities	1,397	491
Fair Value, Measurements, Recurring [Member] \| Level 3
Securities available for sale:
Securities available for sale	578	615
Other assets:
Derivative Assets, Gross Amount	47	57
Other Assets Fair Value, Amount	281	279
Consumer MSRs	80	68
Retained interests in securitizations	201	211
Total assets	906	951
Liabilities:
Derivative Liabilities, Gross Amount	29	27
Total liabilities	29	27
US Treasury securities \| Fair Value, Measurements, Recurring [Member]
Securities available for sale:
Securities available for sale	5,065	4,660
US Treasury securities \| Fair Value, Measurements, Recurring [Member] \| Level 1
Securities available for sale:
Securities available for sale	5,065	4,660
US Treasury securities \| Fair Value, Measurements, Recurring [Member] \| Level 2
Securities available for sale:
Securities available for sale	0	0
US Treasury securities \| Fair Value, Measurements, Recurring [Member] \| Level 3
Securities available for sale:
Securities available for sale	0	0
RMBS \| Fair Value, Measurements, Recurring [Member]
Securities available for sale:
Securities available for sale	29,249	27,311
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	28,731	26,807
RMBS \| Fair Value, Measurements, Recurring [Member] \| Level 3
Securities available for sale:
Securities available for sale	518	504
CMBS \| Fair Value, Measurements, Recurring [Member]
Securities available for sale:
Securities available for sale	4,988	5,379
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	4,937	5,282
CMBS \| Fair Value, Measurements, Recurring [Member] \| Level 3
Securities available for sale:
Securities available for sale	51	97
Other ABS \| Fair Value, Measurements, Recurring [Member]
Securities available for sale:
Securities available for sale	714	1,340
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	714	1,340
Other ABS \| Fair Value, Measurements, Recurring [Member] \| Level 3
Securities available for sale:
Securities available for sale	0	0
Other securities \| Fair Value, Measurements, Recurring [Member]
Securities available for sale:
Securities available for sale	721	371
Other securities \| Fair Value, Measurements, Recurring [Member] \| Level 1
Securities available for sale:
Securities available for sale	295	355
Other securities \| Fair Value, Measurements, Recurring [Member] \| Level 2
Securities available for sale:
Securities available for sale	417	2
Other securities \| Fair Value, Measurements, Recurring [Member] \| Level 3
Securities available for sale:
Securities available for sale	$ 9	$ 14

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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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Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

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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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