DERIVATIVES - Fair Value Hedges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Gain (loss) on fair value hedges
Gain (loss) under mark-to-market approach			$ 41	$ (28)
Gain (loss) under amortization approach			11	2
Other revenue
Gain (loss) on fair value hedges
Gain (loss) on the hedging derivatives included in assessment of the effectiveness of fair value hedges	$ 921	$ (1,491)	961	(1,044)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	(921)	1,490	(961)	1,042
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	54	47	125	127
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	(491)	(1,717)	(492)	(6,383)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	488	1,646	481	6,243
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	0	(5)	0	(11)
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	(491)	(1,717)	(492)	(6,383)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	488	1,646	481	6,243
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	0	(5)	0	(11)
Foreign exchange contracts (gross)
Gain (loss) on fair value hedges
Gain (loss) of cross currency basis included in AOCI		12		76
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	738	(1,234)	1,286	(1,659)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	(738)	1,233	(1,286)	1,657
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	2	73	24	104
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	183	(257)	(325)	615
Gain (loss) on the hedged item in designated and qualifying fair value hedges	(183)	257	325	(615)
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	52	(26)	101	23
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