Fair Value Measurements - Carrying Value and Estimated Fair Value of Financial Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Fair Value Of Other Financial Instrument [Line Items]
Derivatives	$ 5,614	$ 7,258
Deposits	6,919	7,346
Derivatives	6,993	8,413
Level 1 [Member]
Fair Value Of Other Financial Instrument [Line Items]
Short-term financial assets	968	891
Federal funds sold and securities purchased under resale agreements	0	0
Non-derivative trading assets	3,088	2,675
Derivatives	5	10
Securities	21,924	22,048
Commercial loans, net of allowance for credit losses	0	0
Consumer loans, net of allowance for credit losses	0	0
Short-term financial liabilities	0	0
Deposits designated under fair value option	0	0
Non-derivative trading liabilities	363	653
Derivatives	9	8
Short-term borrowings designated under fair value option	0
Long-term debt	0	0
Long-term debt designated under fair value option	0	0
Level 1 [Member] \| Commercial Loans [Member]
Fair Value Of Other Financial Instrument [Line Items]
Commercial loans designated under fair value option and held for sale	0	0
Loans held for sale	0	0
Level 1 [Member] \| Consumer Loans [Member] \| Residential Mortgage [Member]
Fair Value Of Other Financial Instrument [Line Items]
Loans held for sale	0	0
Level 1 [Member] \| Consumer Loans [Member] \| Other consumer [Member]
Fair Value Of Other Financial Instrument [Line Items]
Loans held for sale	0	0
Level 1 [Member] \| Deposits Without Fixed Maturities [Member]
Fair Value Of Other Financial Instrument [Line Items]
Deposits	0	0
Level 1 [Member] \| Deposits With Fixed Maturities [Member]
Fair Value Of Other Financial Instrument [Line Items]
Deposits	0	0
Level 2 [Member]
Fair Value Of Other Financial Instrument [Line Items]
Short-term financial assets	7,478	30,807
Federal funds sold and securities purchased under resale agreements	19,847	1,413
Non-derivative trading assets	5,756	9,722
Derivatives	5,579	7,200
Securities	28,014	21,787
Commercial loans, net of allowance for credit losses	0	0
Consumer loans, net of allowance for credit losses	0	0
Short-term financial liabilities	3,076	12,813
Deposits designated under fair value option	5,052	5,378
Non-derivative trading liabilities	686	52
Derivatives	6,957	8,376
Short-term borrowings designated under fair value option	1,976
Long-term debt	24,874	19,524
Long-term debt designated under fair value option	8,425	8,144
Level 2 [Member] \| Commercial Loans [Member]
Fair Value Of Other Financial Instrument [Line Items]
Commercial loans designated under fair value option and held for sale	151	384
Loans held for sale	55	144
Level 2 [Member] \| Consumer Loans [Member] \| Residential Mortgage [Member]
Fair Value Of Other Financial Instrument [Line Items]
Loans held for sale	7	14
Level 2 [Member] \| Consumer Loans [Member] \| Other consumer [Member]
Fair Value Of Other Financial Instrument [Line Items]
Loans held for sale	0	0
Level 2 [Member] \| Deposits Without Fixed Maturities [Member]
Fair Value Of Other Financial Instrument [Line Items]
Deposits	101,146	105,962
Level 2 [Member] \| Deposits With Fixed Maturities [Member]
Fair Value Of Other Financial Instrument [Line Items]
Deposits	10,508	2,813
Level 3 [Member]
Fair Value Of Other Financial Instrument [Line Items]
Short-term financial assets	48	48
Federal funds sold and securities purchased under resale agreements	0	0
Non-derivative trading assets	3,091	3,093
Derivatives	30	48
Securities	0	0
Commercial loans, net of allowance for credit losses	62,417	58,891
Consumer loans, net of allowance for credit losses	19,185	17,896
Short-term financial liabilities	48	48
Deposits designated under fair value option	1,867	1,968
Non-derivative trading liabilities	0	0
Derivatives	27	29
Short-term borrowings designated under fair value option	0
Long-term debt	0	0
Long-term debt designated under fair value option	746	647
Level 3 [Member] \| Commercial Loans [Member]
Fair Value Of Other Financial Instrument [Line Items]
Commercial loans designated under fair value option and held for sale	0	0
Loans held for sale	1,903	0
Level 3 [Member] \| Consumer Loans [Member] \| Residential Mortgage [Member]
Fair Value Of Other Financial Instrument [Line Items]
Loans held for sale	4	5
Level 3 [Member] \| Consumer Loans [Member] \| Other consumer [Member]
Fair Value Of Other Financial Instrument [Line Items]
Loans held for sale	79	66
Level 3 [Member] \| Deposits Without Fixed Maturities [Member]
Fair Value Of Other Financial Instrument [Line Items]
Deposits	0	0
Level 3 [Member] \| Deposits With Fixed Maturities [Member]
Fair Value Of Other Financial Instrument [Line Items]
Deposits	0	0
Carrying Value [Member]
Fair Value Of Other Financial Instrument [Line Items]
Short-term financial assets	8,494	31,746
Federal funds sold and securities purchased under resale agreements	19,847	1,413
Non-derivative trading assets	11,935	15,490
Derivatives	5,614	7,258
Securities	49,797	43,609
Commercial loans, net of allowance for credit losses	61,674	57,595
Consumer loans, net of allowance for credit losses	20,331	19,466
Short-term financial liabilities	3,082	12,861
Deposits designated under fair value option	6,919	7,346
Non-derivative trading liabilities	1,049	705
Derivatives	6,993	8,413
Short-term borrowings designated under fair value option	1,976
Long-term debt	24,338	18,733
Long-term debt designated under fair value option	9,171	8,791
Carrying Value [Member] \| Commercial Loans [Member]
Fair Value Of Other Financial Instrument [Line Items]
Commercial loans designated under fair value option and held for sale	151	384
Loans held for sale	1,944	144
Carrying Value [Member] \| Consumer Loans [Member] \| Residential Mortgage [Member]
Fair Value Of Other Financial Instrument [Line Items]
Loans held for sale	11	18
Carrying Value [Member] \| Consumer Loans [Member] \| Other consumer [Member]
Fair Value Of Other Financial Instrument [Line Items]
Loans held for sale	79	66
Carrying Value [Member] \| Deposits Without Fixed Maturities [Member]
Fair Value Of Other Financial Instrument [Line Items]
Deposits	101,146	105,962
Carrying Value [Member] \| Deposits With Fixed Maturities [Member]
Fair Value Of Other Financial Instrument [Line Items]
Deposits	10,514	2,810
Estimate of fair value [Member]
Fair Value Of Other Financial Instrument [Line Items]
Short-term financial assets	8,494	31,746
Federal funds sold and securities purchased under resale agreements	19,847	1,413
Non-derivative trading assets	11,935	15,490
Derivatives	5,614	7,258
Securities	49,938	43,835
Commercial loans, net of allowance for credit losses	62,417	58,891
Consumer loans, net of allowance for credit losses	19,185	17,896
Short-term financial liabilities	3,124	12,861
Deposits designated under fair value option	6,919	7,346
Non-derivative trading liabilities	1,049	705
Derivatives	6,993	8,413
Short-term borrowings designated under fair value option	1,976
Long-term debt	24,874	19,524
Long-term debt designated under fair value option	9,171	8,791
Estimate of fair value [Member] \| Commercial Loans [Member]
Fair Value Of Other Financial Instrument [Line Items]
Commercial loans designated under fair value option and held for sale	151	384
Loans held for sale	1,958	144
Estimate of fair value [Member] \| Consumer Loans [Member] \| Residential Mortgage [Member]
Fair Value Of Other Financial Instrument [Line Items]
Loans held for sale	11	19
Estimate of fair value [Member] \| Consumer Loans [Member] \| Other consumer [Member]
Fair Value Of Other Financial Instrument [Line Items]
Loans held for sale	79	66
Estimate of fair value [Member] \| Deposits Without Fixed Maturities [Member]
Fair Value Of Other Financial Instrument [Line Items]
Deposits	101,146	105,962
Estimate of fair value [Member] \| Deposits With Fixed Maturities [Member]
Fair Value Of Other Financial Instrument [Line Items]
Deposits	$ 10,508	$ 2,813

Fair Value of Commercial Syndicated Loans Held For Sale

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Interest bearing deposits domestic fair value option disclosure.

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Short-term financial assets fair value disclosure.

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Short-term Financial Liabilities, Fair Value

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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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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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- Definition

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Fair value portion of federal funds sold and securities borrowed or purchased under agreements to resell.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of consumer loans, including, but not limited to, mortgage, home equity, vehicles, credit card, installment, and lease financing. Excludes loans and leases covered under loss sharing agreements.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents the amount of short-term debt existing as of the balance sheet date.

+ References

No definition available.

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