PRINCIPAL TRANSACTIONS (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Principal transactions revenue
Principal transactions revenue	[1]	$ 9,168	$ 7,585	$ 6,008
Interest rate risks
Principal transactions revenue
Principal transactions revenue		5,124	4,115	3,798
Foreign exchange risks
Principal transactions revenue
Principal transactions revenue		2,488	1,726	1,532
Equity risks
Principal transactions revenue
Principal transactions revenue		491	189	331
Commodity and other risks
Principal transactions revenue
Principal transactions revenue		294	806	750
Credit products and risks
Principal transactions revenue
Principal transactions revenue		771	749	(403)
Operating Segments | Global Consumer Banking
Principal transactions revenue
Principal transactions revenue		570	629	577
Operating Segments | Institutional Clients Group
Principal transactions revenue
Principal transactions revenue		7,740	7,335	5,824
Operating Segments | Corporate/Other
Principal transactions revenue
Principal transactions revenue		$ 858	$ (379)	$ (393)

[1] Certain prior-period revenue and expense lines and totals were reclassified to conform to the current period’s presentation. See Note 3 to the Consolidated Financial Statements.