ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ 24,254	$ 24,342	$ 23,690
Other comprehensive income (loss) before reclassifications	998	(602)	272
Amounts reclassified from AOCI to earnings	627	765	530
Total other comprehensive income (loss), net of tax	1,625	163	802
Ending balance	26,317	24,254	24,342
Total AOCI
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(3,595)	(3,758)	(4,560)
Total other comprehensive income (loss), net of tax	1,625	163	802
Ending balance	(1,970)	(3,595)	(3,758)
Net Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(925)	(1,087)	(1,416)
Other comprehensive income (loss) before reclassifications	250	(531)	(106)
Amounts reclassified from AOCI to earnings	557	693	435
Total other comprehensive income (loss), net of tax	807	162	329
Ending balance	(118)	(925)	(1,087)
Net Unrealized Gains (Losses) on Investment Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(2,369)	(2,338)	(2,771)
Other comprehensive income (loss) before reclassifications	703	(90)	350
Amounts reclassified from AOCI to earnings	63	59	83
Total other comprehensive income (loss), net of tax	766	(31)	433
Ending balance	(1,603)	(2,369)	(2,338)
Defined Benefit Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(301)	(333)	(373)
Other comprehensive income (loss) before reclassifications	45	19	28
Amounts reclassified from AOCI to earnings	7	13	12
Total other comprehensive income (loss), net of tax	52	32	40
Ending balance	$ (249)	$ (301)	$ (333)