PRINCIPAL TRANSACTIONS (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Principal transactions revenue
Principal transactions revenue	[1]	$ 9,062	$ 9,475	$ 7,857
Interest rate risks
Principal transactions revenue
Principal transactions revenue		5,186	5,301	4,229
Foreign exchange risks
Principal transactions revenue
Principal transactions revenue		1,423	2,435	1,699
Equity risks
Principal transactions revenue
Principal transactions revenue		1,346	525	330
Commodity and other risks
Principal transactions revenue
Principal transactions revenue		662	425	899
Credit products and risks
Principal transactions revenue
Principal transactions revenue		$ 445	$ 789	$ 700

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