PARENT COMPANY FINANCIAL STATEMENTS - Schedule of Statements of Cash Flows of Parent Company Only (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Operating Activities
Net income	$ 565	$ 465	$ 485
Other, net	(171)	42	(222)
Net cash flows provided by (used in) operating activities	482	642	423
Investing Activities
Increase in premises and equipment	(106)	(139)	(88)
Net cash flows provided by (used in) investing activities	(1,487)	(1,703)	(2,261)
Financing Activities
Decrease in long-term debt	(1,751)	(341)	(352)
Increase in long-term debt	638	1,379	1,230
Redemption of preferred stock	0	(111)	0
Other, net	10	12	8
Preferred stock	0	(2)	(8)
Common stock	(174)	(175)	(174)
Net cash flows provided by (used in) financing activities	1,084	1,904	1,740
Net Increase (Decrease) in Cash and Cash Equivalents	79	843	(98)
Cash and cash equivalents at beginning of year	2,419	1,576	1,674
Cash and Cash Equivalents at End of Year	2,498	2,419	1,576
Parent Company
Operating Activities
Net income	565	465	485
Undistributed earnings from subsidiaries	(418)	(200)	(136)
Other, net	28	(6)	(4)
Net cash flows provided by (used in) operating activities	175	259	345
Investing Activities
Net increase in advances to subsidiaries	0	0	(75)
Payment for further investment in subsidiaries	(6)	(3)	(9)
Increase in premises and equipment	(5)	(47)	(8)
Net cash flows provided by (used in) investing activities	(11)	(50)	(92)
Financing Activities
Net decrease in advance from affiliate	9	0	0
Net decrease in short-term borrowings	(1)	0	0
Decrease in long-term debt	(475)	0	(331)
Increase in long-term debt	2	499	2
Redemption of preferred stock	0	(111)	0
Other, net	(40)	8	(29)
Preferred stock	0	(2)	(8)
Common stock	(174)	(175)	(174)
Net cash flows provided by (used in) financing activities	(679)	219	(540)
Net Increase (Decrease) in Cash and Cash Equivalents	(515)	428	(287)
Cash and cash equivalents at beginning of year	803	375	662
Cash and Cash Equivalents at End of Year	288	803	375
Interest	$ 72	$ 54	$ 48