INTEREST REVENUE AND EXPENSE (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Interest revenue
Loan interest, including fees	$ 10,149	$ 11,981	$ 21,399	$ 23,949
Deposits with banks	159	736	686	1,343
Securities borrowed and purchased under agreements to resell	401	1,893	1,609	3,677
Investments, including dividends	2,097	2,505	4,378	5,053
Trading account assets	1,673	2,140	3,263	3,826
Other interest	110	457	393	940
Total interest revenue	14,589	19,712	31,728	38,788
Interest expense
Deposits	1,469	3,284	4,083	6,311
Securities loaned and sold under agreements to repurchase	453	1,724	1,538	3,313
Trading account liabilities	144	320	383	647
Short-term borrowings and other interest-bearing liabilities	140	715	524	1,367
Long-term debt	1,303	1,719	2,628	3,441
Total interest expense	3,509	7,762	9,156	15,079
Net interest revenue	11,080	11,950	22,572	23,709
Provision for credit losses on loans	7,696	2,089	14,140	4,033
Net interest revenue after provision for credit losses on loans	3,384	9,861	8,432	19,676
Insurance fees and charges	$ 270	$ 189	$ 495	$ 382