PARENT COMPANY FINANCIALS - Condensed Cash Flow Statements (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
OPERATING ACTIVITIES
Net income		$ 1,831	$ 1,509	$ 1,608
Adjustments to reconcile net income to net change due to operating activities:
Deferred income tax expense (benefit)		(82)	(177)	(242)
Net increase (decrease) in Other liabilities		(395)	(310)	(339)
Net (increase) decrease in Other assets		89	(261)	612
Net change due to operating activities		2,211	2,001	2,961
INVESTING ACTIVITIES
Other investing, net		(347)	(93)	(61)
Net change due to investing activities		(5,967)	2,987	5,248
FINANCING ACTIVITIES
Proceeds from issuance of long-term borrowed funds		8,534	13,185	25,983
Repayments of long-term borrowed funds		(9,744)	(14,286)	(28,418)
Treasury stock purchased		(600)	(1,050)	(906)
Net proceeds from issuance of preferred stock		393	392	0
Redemption of preferred stock		(400)	(300)	0
Dividends paid to preferred stockholders		(133)	(134)	(120)
Other financing, net		(8)	18	21
Net change due to financing activities		5,882	(6,015)	(7,128)
Net change in cash and cash equivalents	[1]	2,126	(1,027)	1,081
Cash and cash equivalents at beginning of period	[1]	10,601	11,628	10,547
Cash and cash equivalents at end of period	[1]	12,727	10,601	11,628
Parent company
OPERATING ACTIVITIES
Net income		1,831	1,509	1,608
Adjustments to reconcile net income to net change due to operating activities:
Deferred income tax expense (benefit)		(12)	(10)	(4)
Equity in undistributed (income) losses of subsidiaries		(853)	(975)	1,202
Other, net		132	108	96
Net increase (decrease) in Other liabilities		18	92	(17)
Net (increase) decrease in Other assets		(182)	(84)	17
Net change due to operating activities		934	640	2,902
INVESTING ACTIVITIES
Investments in and advances to subsidiaries		(129)	(2,249)	(76)
Repayment of investments in and advances to subsidiaries		80	120	30
Other investing, net		2	2	0
Net change due to investing activities		(47)	(2,127)	(46)
FINANCING ACTIVITIES
Proceeds from issuance of long-term borrowed funds		746	3,231	0
Repayments of long-term borrowed funds		(470)	(107)	0
Treasury stock purchased		(600)	(1,050)	(906)
Net proceeds from issuance of preferred stock		393	392	0
Redemption of preferred stock		(400)	(300)	0
Dividends paid to common stockholders		(755)	(769)	(808)
Dividends paid to preferred stockholders		(133)	(134)	(120)
Other financing, net		(8)	18	21
Net change due to financing activities		(1,227)	1,281	(1,813)
Net change in cash and cash equivalents		(340)	(206)	1,043
Cash and cash equivalents at beginning of period		2,658	2,864	1,821
Cash and cash equivalents at end of period		$ 2,318	$ 2,658	$ 2,864

[1] Cash and cash equivalents include Cash and due from banks and Interest-bearing cash and due from banks as reflected on the Consolidated Balance Sheets