Income Taxes - Schedule of Effective Income Tax Reconciliation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Federal income tax rate	21.00%	21.00%	21.00%
Tax computed at statutory rate	$ 270	$ 196	$ 123
Increase (decrease) resulting from:
State income taxes, net of federal income tax benefit	32	9	15
Bank-owned life insurance	(7)	(6)	(5)
401(k) – employee stock ownership plan	(1)	(1)	(1)
Tax-exempt interest	(10)	(8)	(6)
Non-deductible expenses	8	13	11
LIHTC credits and benefits, net of amortization	(14)	(9)	(4)
Other tax credits	(4)	(5)	0
Other changes in unrecognized tax benefits	4	(9)	4
Purchase accounting gain	0	(112)	0
Other	(4)	8	(3)
Total	$ 274	$ 76	$ 134