INTEREST REVENUE AND EXPENSE (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Interest revenue
Loan interest, including fees	$ 9,421	$ 11,993	$ 30,820	$ 35,942
Deposits with banks	116	736	802	2,079
Securities borrowed and purchased under agreements to resell	352	1,745	1,961	5,422
Investments, including dividends	1,870	2,411	6,248	7,464
Trading account assets	1,457	1,893	4,720	5,719
Other interest	98	399	491	1,339
Total interest revenue	13,314	19,177	45,042	57,965
Interest expense
Deposits	1,293	3,369	5,376	9,680
Securities loaned and sold under agreements to repurchase	292	1,630	1,830	4,943
Trading account liabilities	123	345	506	992
Short-term borrowings and other interest-bearing liabilities	88	609	612	1,976
Long-term debt	1,025	1,583	3,653	5,024
Total interest expense	2,821	7,536	11,977	22,615
Net interest revenue	10,493	11,641	33,065	35,350
Provision for credit losses on loans	1,809	2,062	15,949	6,095
Net interest revenue after provision for credit losses on loans	8,684	9,579	17,116	29,255
Insurance fees and charges	$ 375	$ 199	$ 870	$ 581