DERIVATIVES - Gains (Losses) Included in Other Revenue (Details) - Other revenue - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative gain (losses)
Gains (losses) recognized in Other revenue related to derivatives not designated in a qualifying hedging relationship	$ (17)	$ 16	$ (126)	$ 153
Interest rate contracts
Derivative gain (losses)
Gains (losses) recognized in Other revenue related to derivatives not designated in a qualifying hedging relationship	9	(3)	(66)	171
Foreign exchange contracts
Derivative gain (losses)
Gains (losses) recognized in Other revenue related to derivatives not designated in a qualifying hedging relationship	$ (26)	$ 19	$ (60)	$ (18)