DERIVATIVES ACTIVITIES - Fair Value Hedges (Details) - Other revenue - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Gain (loss) on fair value hedges
Gain (loss) on the derivatives in designated and qualifying fair value hedges	$ (371)	$ (1,109)	$ (1,393)	$ 768
Gain (loss) on the hedged item in designated and qualifying fair value hedges	345	1,165	1,464	(650)
Hedge ineffectiveness recognized in earnings on designated and qualifying fair value hedges	(22)	(14)	1	(5)
Net gain (loss) excluded from assessment of the effectiveness of fair value hedges	(4)	70	70	123
Interest rate contracts
Gain (loss) on fair value hedges
Gain (loss) on the derivatives in designated and qualifying fair value hedges	(194)	(450)	(570)	2,747
Gain (loss) on the hedged item in designated and qualifying fair value hedges	189	442	532	(2,701)
Hedge ineffectiveness recognized in earnings on designated and qualifying fair value hedges	(5)	(11)	(31)	48
Net gain (loss) excluded from assessment of the effectiveness of fair value hedges	0	3	(7)	(2)
Foreign exchange contracts
Gain (loss) on fair value hedges
Gain (loss) on the derivatives in designated and qualifying fair value hedges	(166)	(602)	(803)	(2,360)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	144	664	910	2,425
Hedge ineffectiveness recognized in earnings on designated and qualifying fair value hedges	(17)	(3)	32	(53)
Net gain (loss) excluded from assessment of the effectiveness of fair value hedges	(5)	65	75	118
Commodity and other contracts
Gain (loss) on fair value hedges
Gain (loss) on the derivatives in designated and qualifying fair value hedges	(11)	(57)	(20)	381
Gain (loss) on the hedged item in designated and qualifying fair value hedges	12	59	22	(374)
Net gain (loss) excluded from assessment of the effectiveness of fair value hedges	$ 1	$ 2	$ 2	$ 7