Parent Company Financial Information - Statements of Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Dividend income:
Other income	$ 88	$ 93	$ 103
Interest expense - term borrowings	78	67	72
Personnel and other expense	1,159	1,137	1,100
Income before income taxes	1,280	1,005	1,128
Income tax expense (benefit)	282	211	212
Equity in undistributed net income (loss) of subsidiaries:
Net income attributable to controlling interest	982	775	897
Parent Company
Dividend income:
Bank	1,005	1,110	220
Non-bank	5	0	0
Total dividend income	1,010	1,110	220
Other income	0	1	226
Total income	1,010	1,111	446
Interest expense - term borrowings	29	15	21
Personnel and other expense	110	111	114
Total expense	139	126	135
Income before income taxes	871	985	311
Income tax expense (benefit)	(27)	(27)	24
Income before equity in undistributed net income (loss) of subsidiaries	898	1,012	287
Equity in undistributed net income (loss) of subsidiaries:
Bank	88	(238)	613
Non-bank	(4)	1	(3)
Net income attributable to controlling interest	$ 982	$ 775	$ 897