DERIVATIVES - Fair Value Hedges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Gain (loss) on fair value hedges
Gain (loss) on derivatives, mark to market approach	$ 321	$ 284
Gain (loss) on derivatives, amortization approach	75	28
Other revenue
Gain (loss) on fair value hedges
Gain (loss) on the hedging derivatives included in assessment of the effectiveness of fair value hedges	545	1,387	$ (3,245)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	(545)	(1,387)	3,242
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	432	314	265
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	(1,073)	(804)	(8,322)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	1,071	795	8,087
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	0	0	0
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	(1,073)	(804)	(8,322)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	1,071	795	8,087
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	0	0	0
Foreign exchange contracts
Gain (loss) on fair value hedges
Cross-currency basis included in accumulated other comprehensive income	(19)	(70)
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	(112)	1,433	(1,375)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	112	(1,433)	1,372
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	36	2	171
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	657	(46)	(1,870)
Gain (loss) on the hedged item in designated and qualifying fair value hedges	(657)	46	1,870
Net gain (loss) on the hedging derivatives excluded from assessment of the effectiveness of fair value hedges	396	312	94
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