INTEREST REVENUE AND EXPENSE (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest revenue
Loan interest, including fees	$ 40,185	$ 47,751	$ 45,682
Deposits with banks	928	2,682	2,203
Securities borrowed and purchased under agreements to resell	2,283	6,872	5,492
Investments, including dividends	7,989	9,860	9,494
Trading account assets	6,125	7,672	6,284
Other interest-bearing assets	579	1,673	1,673
Total interest revenue	58,089	76,510	70,828
Interest expense
Deposits	6,537	12,633	9,616
Securities loaned and sold under agreements to repurchase	2,077	6,263	4,889
Trading account liabilities	628	1,308	1,001
Short-term borrowings and other interest-bearing liabilities	630	2,465	2,209
Long-term debt	4,669	6,494	6,551
Total interest expense	14,541	29,163	24,266
Net interest revenue	43,548	47,347	46,562
Provision for credit losses on loans	15,922	8,218	7,354
Net interest revenue after provision for loan losses	27,626	39,129	39,208
Insurance fees and charges	$ 1,203	$ 781	$ 1,182

The insurance fees and other charges paid for deposits.

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Interest and dividend income on all securities excluding trading securities.

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Represents the total of interest and dividend income, including any amortization and accretion (as applicable) of discounts and premiums, earned from (1) loans and leases whether held-for-sale or held-in-portfolio; (2) investment securities; (3) federal funds sold; (4) securities purchased under agreements to resell; (5) investments in banker's acceptances, commercial paper, or certificates of deposit; (6) dividend income; or (7) other investments not otherwise specified herein.

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The aggregate interest and fee income generated by: (1) loans the Entity has positive intent and ability to hold for the foreseeable future, or until maturity or payoff, including commercial and consumer loans, whether domestic or foreign, which may consist of: (a) industrial and agricultural; (b) real estate; and (c) real estate construction loans; (d) trade financing; (e) lease financing; (f) home equity lines-of-credit; (g) automobile and other vehicle loans; and (h) credit card and other revolving-type loans and (2) loans and leases held-for-sale which may include mortgage loans, direct financing, and sales-type leases.

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Amount of the cost of borrowed funds accounted for as interest expense.

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Aggregate amount of interest expense on all deposits.

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The aggregate expense incurred on federal funds purchased and securities sold under agreements to repurchase. If amounts recognized as payables under repurchase agreements have been offset against amounts recognized as receivables under reverse repurchase agreements and reported as a net amount on the balance sheet, the income and expense from these agreements may be reported on a net basis.

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Aggregate amount of interest paid or due on all long-term debt.

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The aggregate interest expense incurred on short-term borrowings including commercial paper, Federal Home Loan Bank and Federal Reserve Bank advances and other short term borrowings.

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Interest expense incurred on short positions arising from sales of securities and other assets, which the entity does not own, to other parties. Trading liabilities includes the fair value of derivative contracts held for trading that are in loss positions.

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Interest income derived from funds deposited with both domestic and foreign financial institutions including funds in money market and other accounts.

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Amount of interest income or expense, including any amortization and accretion (as applicable) of discounts and premiums, including consideration of the provisions for loan, lease, credit, and other related losses.

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The net amount of operating interest income (expense).

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The aggregate interest income earned from (1) the lending of excess federal funds to another commercial bank requiring such for its legal reserve requirements and (2) securities purchased under agreements to resell.

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Amount, after discount, accretion and premium amortization, of interest income and dividend income classified as other.

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Amount of credit loss expense (reversal of expense) for financing receivable.

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