DERIVATIVES - Fair Value Hedges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Other revenue
Gain (loss) on fair value hedges
Gain (loss) on the hedging derivatives included in assessment of the effectiveness of fair value hedges	$ (1,491)	$ (57)	$ (1,044)	$ (556)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	1,490	57	1,042	556
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	47	(40)	127	(58)
Net interest income
Gain (loss) on fair value hedges
Gain (loss) on the hedging derivatives included in assessment of the effectiveness of fair value hedges	(1,717)	454	(6,383)	(3,481)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	1,646	(559)	6,243	3,267
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	(5)	1	(11)	(3)
Interest rate contracts (gross) | Other revenue
Gain (loss) on fair value hedges
Gain (loss) on the hedging derivatives included in assessment of the effectiveness of fair value hedges	0	0	0	0
Gain (loss) on the hedged item in designated and qualifying fair value hedges	0	0	0	0
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	0	0	0	0
Interest rate contracts (gross) | Net interest income
Gain (loss) on fair value hedges
Gain (loss) on the hedging derivatives included in assessment of the effectiveness of fair value hedges	(1,717)	454	(6,383)	(3,481)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	1,646	(559)	6,243	3,267
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	(5)	1	(11)	(3)
Foreign exchange contracts (gross)
Gain (loss) on fair value hedges
Amount of cross currency basis included in AOCI	12	(13)	76	(26)
Foreign exchange contracts (gross) | Other revenue
Gain (loss) on fair value hedges
Gain (loss) on the hedging derivatives included in assessment of the effectiveness of fair value hedges	(1,234)	220	(1,659)	10
Gain (loss) on the hedged item in designated and qualifying fair value hedges	1,233	(220)	1,657	(10)
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	73	13	104	17
Foreign exchange contracts (gross) | Net interest income
Gain (loss) on fair value hedges
Gain (loss) on the hedging derivatives included in assessment of the effectiveness of fair value hedges	0	0	0	0
Gain (loss) on the hedged item in designated and qualifying fair value hedges	0	0	0	0
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	0	0	0	0
Commodity hedges | Other revenue
Gain (loss) on fair value hedges
Gain (loss) on the hedging derivatives included in assessment of the effectiveness of fair value hedges	(257)	(277)	615	(566)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	257	277	(615)	566
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	(26)	(53)	23	(75)
Commodity hedges | Net interest income
Gain (loss) on fair value hedges
Gain (loss) on the hedging derivatives included in assessment of the effectiveness of fair value hedges	0	0	0	0
Gain (loss) on the hedged item in designated and qualifying fair value hedges	0	0	0	0
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	$ 0	$ 0	$ 0	$ 0