Summary of Significant Accounting Policies - Additional Information (Detail)		12 Months Ended
	Jan. 01, 2020 USD ($)	Dec. 31, 2021 USD ($) Segment shares	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Significant Accounting Policies [Line Items]
Cash and cash equivalents, interest-bearing deposits in other financial institutions		$ 2,211,000,000	$ 1,948,000,000	$ 742,000,000	$ 1,475,000,000
Cash and cash equivalents, interest-bearing deposits in other financial institutions, Federal Reserve Bank of New York		1,700,000,000	1,600,000,000
Cash and cash equivalents, federal funds sold		0	0
Cash and cash equivalents, outstanding reverse repurchase agreements		406,000,000	193,000,000
Allowance for loan and lease losses		199,000,000	194,000,000	148,000,000
Retained earnings		741,000,000	494,000,000
Increase in allowance for credit losses on loans and leases	$ 2,000,000	15,000,000	3,000,000
Off-balance sheet credit exposures before adoption of CECL	13,000,000
Goodwill		$ 2,426,000,000	2,426,000,000
Number of operating segments | Segment		1
Number of reportable segments | Segment		1
Goodwill impairment		$ 0
Depreciation		21,000,000	24,000,000	27,000,000
Bank-owned life insurance		1,184,000,000	1,164,000,000
Bank-owned life insurance income		29,000,000	32,000,000	28,000,000
Other real estate owned		$ 3,000,000	2,000,000
Shares available for grant | shares		8,548,783
Taxi Medallion Loans
Significant Accounting Policies [Line Items]
Other real estate owned		$ 5,000,000	7,000,000
Premises
Significant Accounting Policies [Line Items]
Premises, furniture, fixtures, and equipment, estimated useful lives (in years)		20 years
Furniture, Fixtures and Equipment | Minimum
Significant Accounting Policies [Line Items]
Premises, furniture, fixtures, and equipment, estimated useful lives (in years)		3 years
Furniture, Fixtures and Equipment | Maximum
Significant Accounting Policies [Line Items]
Premises, furniture, fixtures, and equipment, estimated useful lives (in years)		10 years
Unfunded Commitments
Significant Accounting Policies [Line Items]
Allowance for credit losses		$ 12,000,000	$ 12,000,000	$ 1,000,000
Accounting Standards Update 2016-13
Significant Accounting Policies [Line Items]
Retained earnings	$ 2,000,000
Accounting Standards Update 2020-04
Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted [true false]		true
Change in accounting principle, accounting standards update, adoption date		Mar. 31, 2020
Change in accounting principle, accounting standards update, immaterial effect [true false]		true