Income Taxes - Schedule of Effective Income Tax Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Federal income tax rate	21.00%	21.00%	21.00%
Tax computed at statutory rate	$ 237	$ 243	$ 270
Increase (decrease) resulting from:
State income taxes, net of federal income tax benefit	34	31	32
Bank-owned life insurance	(6)	(4)	(7)
Tax-exempt interest	(12)	(10)	(10)
Deposit insurance expense	11	7	5
Non-deductible expenses	9	4	3
LIHTC credits and benefits, net of amortization	(15)	(16)	(14)
Other tax credits	(5)	(4)	(4)
Other changes in unrecognized tax benefits	(50)	(2)	4
Termination of BOLI policies	21	0	0
Other	(12)	(2)	(5)
Total	$ 212	$ 247	$ 274