OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 6,302	$ 6,050
Other comprehensive income (loss) before reclassifications	42
Amounts reclassified from AOCI	6
Other Comprehensive Income (Loss)	48	(15)
Balance at end of period	6,418	6,006
Unrealized Net Gains (Losses) on Debt Securities Available for Sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(119)
Other comprehensive income (loss) before reclassifications	33
Amounts reclassified from AOCI	0
Other Comprehensive Income (Loss)	33
Balance at end of period	(86)
Unrealized Net Gains (Losses) on Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(15)
Other comprehensive income (loss) before reclassifications	8
Amounts reclassified from AOCI	6
Other Comprehensive Income (Loss)	14
Balance at end of period	(1)
Unrecognized Pension and Postretirement Obligations
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(35)
Other comprehensive income (loss) before reclassifications	1
Amounts reclassified from AOCI	0
Other Comprehensive Income (Loss)	1
Balance at end of period	(34)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(169)	(235)
Balance at end of period	$ (121)	$ (250)