DERIVATIVES - Fair Value Hedges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Gain (loss) on fair value hedges
Gain (loss) on derivatives, mark to market approach	$ 284	$ 86
Gain (loss) on derivatives, amortization approach	28	8
Other revenue
Gain (loss) on fair value hedges
Gain (loss) on the hedging derivatives included in assessment of the effectiveness of fair value hedges	1,387	(3,245)	$ (4,610)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	(1,387)	3,242	4,601
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	314	265	84
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	(804)	(8,322)	(5,425)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	795	8,087	5,043
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	0	0	(9)
Interest rate 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	0	0	0
Gain (loss) on the hedged item in designated and qualifying fair value hedges	0	0	0
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	0	0	0
Interest rate 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	(804)	(8,322)	(5,425)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	795	8,087	5,043
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	0	0	(9)
Foreign exchange contracts
Gain (loss) on fair value hedges
Cross-currency basis included in accumulated other comprehensive income	(70)	73
Foreign exchange contracts | Other revenue
Gain (loss) on fair value hedges
Gain (loss) on the hedging derivatives included in assessment of the effectiveness of fair value hedges	1,433	(1,375)	(627)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	(1,433)	1,372	628
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	2	171	79
Foreign exchange contracts | 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
Gain (loss) on the hedged item in designated and qualifying fair value hedges	0	0	0
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	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	(46)	(1,870)	(3,983)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	46	1,870	3,973
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	312	94	5
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
Gain (loss) on the hedged item in designated and qualifying fair value hedges	0	0	0
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	$ 0	$ 0	$ 0