Parent Company Financial Information - Statements of Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Dividend income:
Other income	$ 93	$ 103	$ 75
Interest expense - term borrowings	67	72	72
Personnel and other expense	1,137	1,100	1,101
Income before income taxes	1,005	1,128	1,159
Income tax expense (benefit)	211	212	247
Equity in undistributed net income (loss) of subsidiaries:
Net income attributable to controlling interest	775	897	900
Parent Company
Dividend income:
Bank	1,110	220	435
Non-bank	0	0	16
Total dividend income	1,110	220	451
Other income	1	226	22
Total income	1,111	446	473
Interest expense - term borrowings	15	21	31
Personnel and other expense	111	114	128
Total expense	126	135	159
Income before income taxes	985	311	314
Income tax expense (benefit)	(27)	24	(31)
Income before equity in undistributed net income (loss) of subsidiaries	1,012	287	345
Equity in undistributed net income (loss) of subsidiaries:
Bank	(238)	613	561
Non-bank	1	(3)	(6)
Net income attributable to controlling interest	$ 775	$ 897	$ 900