Discontinued Operations - Summary of Operating Results of the Discontinued Insurance Agency Business (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Interest on other earning assets	$ 24	$ 1
Total interest income	24	1
Insurance income	892	815
Other income	5	3
Total noninterest income	897	818
Personnel expense	634	513
Professional fees and outside processing	48	27
Software expense	17	14
Net occupancy expense	15	14
Amortization of intangibles	21	36
Equipment expense	9	8
Marketing and customer development	10	10
Restructuring charges	19	7
Other expense	58	52
Total noninterest expense	831	681
Income before income taxes from discontinued operations	90	138
Provision for income taxes	23	33
Net income from discontinued operations	67	105
Net Income (Loss) Attributable to Noncontrolling Interest	3	2
Net income from discontinued operations attributable to controlling interest	$ 64	$ 103