Federal, State and Local Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Income tax expense	$ 210,000,000	$ 77,000,000	$ 128,000,000
CARES Act allowance of net operating losses		5 years
Outstanding amount of the investment	76,000,000	$ 85,000,000
Other commitments of additional anticipated equity contributions relating to current investments	34,000,000	54,000,000
Affordable housing tax credits and other tax benefits recognized	9,000,000	8,000,000	6,000,000
Affordable housing tax credits and other tax benefits, related amortization recognized	9,000,000	6,000,000	5,000,000
Impairment losses on other assets	0	0	0
Unrecognized gross tax benefits	39,000,000	38,000,000	36,000,000	$ 33,000,000
Total amount of net unrecognized tax benefits that would affect the effective tax rate, if recognized	30,000,000
Income tax benefit attributed to interest and penalties	4,000,000	3,000,000	$ 3,000,000
Accrued interest and penalties on tax liabilities	22,000,000	18,000,000
Net deferred tax liabilities	384,000,000	420,000,000
Special Federal Tax Provision
Income Taxes [Line Items]
Tax bad debt base-year reserves	62,000,000
Net deferred tax liabilities	13,000,000
Maximum
Income Taxes [Line Items]
Estimated change in balance of unrecognized tax benefit, within next twelve months	21,000,000
CARES Act
Income Taxes [Line Items]
Income tax expense		$ 68,400,000
Domestic Tax Authority
Income Taxes [Line Items]
Net operating loss carryforward	$ 21,000,000
Operating loss carryforward period	20 years