ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 25,234	$ 23,869	$ 24,254	$ 24,342
Other comprehensive income (loss) before reclassifications	207	991	836	259
Amounts reclassified from AOCI to earnings	165	218	492	573
Total other comprehensive income (loss), net	372	1,209	1,328	832
Ending balance	25,829	24,932	25,829	24,932
Total AOCI
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(2,639)	(4,135)	(3,595)	(3,758)
Total other comprehensive income (loss), net	372	1,209	1,328	832
Ending balance	(2,267)	(2,926)	(2,267)	(2,926)
Net Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(341)	(1,302)	(925)	(1,087)
Other comprehensive income (loss) before reclassifications	(16)	450	275	(84)
Amounts reclassified from AOCI to earnings	144	203	437	522
Total other comprehensive income (loss), net	128	653	712	438
Ending balance	(213)	(649)	(213)	(649)
Net Unrealized Gains (Losses) on Investment Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(2,001)	(2,511)	(2,369)	(2,338)
Other comprehensive income (loss) before reclassifications	223	541	561	339
Amounts reclassified from AOCI to earnings	18	13	48	42
Total other comprehensive income (loss), net	241	554	609	381
Ending balance	(1,760)	(1,957)	(1,760)	(1,957)
Defined Benefit Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(297)	(322)	(301)	(333)
Other comprehensive income (loss) before reclassifications	0	0	0	4
Amounts reclassified from AOCI to earnings	3	2	7	9
Total other comprehensive income (loss), net	3	2	7	13
Ending balance	$ (294)	$ (320)	$ (294)	$ (320)