ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME - Schedule of Changes in Components of AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, shareholders' equity	$ 22,228	$ 21,255
AOCI activity before reclassifications	249
Amounts reclassified from AOCI to earnings	(3)
Other comprehensive income (loss), net of tax	246	(91)
Ending balance, shareholders' equity	22,295	21,848
Total accumulated other comprehensive loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, shareholders' equity	(445)	(491)
Other comprehensive income (loss), net of tax	246	(91)
Ending balance, shareholders' equity	(199)	(582)
Unrealized loss on securities available for sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, shareholders' equity	(584)	(577)
AOCI activity before reclassifications	239
Amounts reclassified from AOCI to earnings	0
Other comprehensive income (loss), net of tax	239	(91)
Ending balance, shareholders' equity	(345)	(668)
Unrealized loss on securities available for sale transferred to held to maturity
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, shareholders' equity	(4)	(5)
AOCI activity before reclassifications	0
Amounts reclassified from AOCI to earnings	0
Other comprehensive income (loss), net of tax	0	0
Ending balance, shareholders' equity	(4)	(5)
Defined benefit pension items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, shareholders' equity	135	91
AOCI activity before reclassifications	0
Amounts reclassified from AOCI to earnings	0
Other comprehensive income (loss), net of tax	0	0
Ending balance, shareholders' equity	135	91
Unrealized gain on cash flow hedge derivatives
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance, shareholders' equity	8	0
AOCI activity before reclassifications	10	0
Amounts reclassified from AOCI to earnings	(3)	0
Other comprehensive income (loss), net of tax	7	0
Ending balance, shareholders' equity	$ 15	$ 0