INTEREST REVENUE AND EXPENSE (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Interest revenue
Loan interest, including fees	$ 11,190	$ 10,293	$ 22,082	$ 20,338
Deposits with banks	493	375	925	670
Federal funds sold and securities borrowed or purchased under agreements to resell	1,336	829	2,375	1,490
Investments, including dividends	2,374	2,058	4,608	4,018
Trading account assets	1,763	1,481	3,134	2,747
Other interest	394	258	758	552
Total interest revenue	17,550	15,294	33,882	29,815
Interest expense
Deposits	2,244	1,603	4,241	3,018
Federal funds purchased and securities loaned or sold under agreements to repurchase	1,224	676	2,173	1,169
Trading account liabilities	236	146	451	293
Short-term borrowings	523	202	994	401
Long-term debt	1,658	1,409	3,186	2,721
Total interest expense	5,885	4,036	11,045	7,602
Net interest revenue	11,665	11,258	22,837	22,213
Provision for loan losses	1,795	1,666	3,598	3,341
Net interest revenue after provision for loan losses	9,870	9,592	19,239	18,872
Insurance fees and charges	$ 319	$ 329	$ 695	$ 634