ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 23,869	$ 23,585	$ 24,342	$ 23,690
Other comprehensive income (loss) before reclassifications	991	(826)	259	(1,070)
Amounts reclassified to the Consolidated Statements of Operations	218	146	573	387
Total other comprehensive income (loss), net of income taxes	1,209	(680)	832	(683)
Ending balance	24,932	22,878	24,932	22,878
Total AOCI
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(4,135)	(4,563)	(3,758)	(4,560)
Total other comprehensive income (loss), net of income taxes	1,209	(680)	832	(683)
Ending balance	(2,926)	(5,243)	(2,926)	(5,243)
Net Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(1,302)	(1,553)	(1,087)	(1,416)
Other comprehensive income (loss) before reclassifications	450	(248)	(84)	(580)
Amounts reclassified to the Consolidated Statements of Operations	203	120	522	315
Total other comprehensive income (loss), net of income taxes	653	(128)	438	(265)
Ending balance	(649)	(1,681)	(649)	(1,681)
Net Unrealized Gains (Losses) on Investment Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(2,511)	(2,643)	(2,338)	(2,771)
Other comprehensive income (loss) before reclassifications	541	(578)	339	(490)
Amounts reclassified to the Consolidated Statements of Operations	13	23	42	63
Total other comprehensive income (loss), net of income taxes	554	(555)	381	(427)
Ending balance	(1,957)	(3,198)	(1,957)	(3,198)
Defined Benefit Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(322)	(367)	(333)	(373)
Other comprehensive income (loss) before reclassifications	0	0	4	0
Amounts reclassified to the Consolidated Statements of Operations	2	3	9	9
Total other comprehensive income (loss), net of income taxes	2	3	13	9
Ending balance	$ (320)	$ (364)	$ (320)	$ (364)