Parent Company Financial Statements - Schedule of Condensed Statements of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
OPERATING ACTIVITIES
Net income	$ 1,098	$ 547	$ 492
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Deferred tax expense	206	(8)	(26)
Fair value adjustment on marketable equity securities, net	3	(34)	(29)
Stock based compensation expense	19	0	0
Net change in other assets	484	(733)	(135)
Net change in other liabilities	260	5	(15)
Net cash provided by (used in) operating activities	2,791	(284)	376
CASH FLOWS FROM INVESTING ACTIVITIES
Purchase of marketable equity securities	0	(2)	(333)
Proceeds from sales of investments in marketable equity securities	0	30	353
Acquisition, net of cash acquired	134	0	(60)
Net cash provided by (used in) investing activities	75	(7,568)	(9,908)
CASH FLOWS FROM FINANCING ACTIVITIES
Repayment of long-term borrowings	(5,099)	(54)	(87)
Net proceeds from issuance of preferred stock	0	0	340
Repurchase of Class A common stock	(1,240)	0	(334)
Cash dividends paid	(83)	(42)	(30)
Other financing activities	(24)	0	0
Net cash (used in) provided by financing activities	(2,686)	7,828	9,517
Change in cash and due from banks	180	(24)	(15)
Cash and due from banks at beginning of year	338	362	377
Cash and due from banks at end of year	518	338	362
CASH PAYMENTS (REFUNDS) FOR:
(Refunds) payments for income taxes	(551)	870	117
Parent
OPERATING ACTIVITIES
Net income	1,098	547	492
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Distributed (undistributed) net income of subsidiaries	221	(368)	(259)
Deferred tax expense	48	0	0
Net amortization of premiums and discounts	1	1	1
Fair value adjustment on marketable equity securities, net	6	(34)	(29)
Stock based compensation expense	19	0	0
Net change in due to/from subsidiaries	0	4	(3)
Net change in other assets	(3)	7	(3)
Net change in other liabilities	(2)	3	(1)
Net cash provided by (used in) operating activities	1,388	160	198
CASH FLOWS FROM INVESTING ACTIVITIES
Net decrease (increase) in interest-earning deposits at banks	3	(4)	1
Purchase of marketable equity securities	0	(2)	(333)
Proceeds from sales of investments in marketable equity securities	0	30	353
Proceeds from sales, calls, and maturities of investment securities	0	2	1
Investment in subsidiaries	0	0	(423)
Acquisition, net of cash acquired	(51)	0	0
Net cash provided by (used in) investing activities	(48)	26	(401)
CASH FLOWS FROM FINANCING ACTIVITIES
Repayment of short-term borrowings	0	0	(40)
Repayment of long-term borrowings	(68)	(20)	(33)
Net proceeds from issuance of subordinated debt	0	0	346
Proceeds from borrowings due to banking subsidiary	20	0	0
Net proceeds from issuance of preferred stock	0	0	340
Repurchase of Class A common stock	(1,240)	0	(334)
Cash dividends paid	(83)	(42)	(31)
Other financing activities	(24)	0	0
Net cash (used in) provided by financing activities	(1,395)	(62)	248
Change in cash and due from banks	(55)	124	45
Cash and due from banks at beginning of year	174	50	5
Cash and due from banks at end of year	119	174	50
CASH PAYMENTS (REFUNDS) FOR:
Interest	18	17	13
(Refunds) payments for income taxes	$ (536)	$ 810	$ 107