DERIVATIVES - Fair Value Hedges (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Gain (loss) on fair value hedges
Gain (loss) under mark-to-market approach			$ 93	$ 2
Gain (loss) under amortization approach			7	5
Other revenue
Gain (loss) on fair value hedges
Gain (loss) on the hedging derivatives included in assessment of the effectiveness of fair value hedges	$ (288)	$ (1,941)	673	(2,985)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	288	1,941	(673)	2,983
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	109	86	234	213
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	19	(1,855)	(473)	(8,238)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	(21)	1,793	460	8,036
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	0	0	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	19	(1,855)	(473)	(8,238)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	(21)	1,793	460	8,036
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	0	0	0	(11)
Foreign exchange contracts (gross)
Gain (loss) on fair value hedges
Gain (loss) of cross currency basis included in AOCI		40		116
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	(577)	(964)	709	(2,623)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	577	964	(709)	2,621
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	9	79	33	183
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	289	(977)	(36)	(362)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	(289)	977	36	362
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	100	7	201	30
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