Federal, State and Local Taxes - Reconciliation of Statutory Federal Income Tax Expense (Benefit) Reported in Net Income to Combined Actual Income Tax Expense (Benefit) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Statutory federal income tax at 21%	$ 174	$ 169	$ 123
State and local income taxes, net of federal income tax effect	31	40	27
Effect of tax law changes			(73)
Non-taxable bargain gain	(33)
Non-deductible FDIC deposit insurance premiums	10	9	8
Effect of tax deductibility of ESOP	(3)	(3)	(3)
Non-taxable income and expense of BOLI	(7)	(6)	(7)
Non-deductible merger expense	3	3
Non-deductible compensation expense	4
Federal tax credits	(1)		(1)
Adjustments relating to prior tax years	(1)	(1)	1
Other, net	(1)	(1)	2
Income tax expense reported in net income	$ 176	$ 210	$ 77