Borrowed Funds - Additional Information (Details)		12 Months Ended
	Nov. 04, 2002 USD ($) Age $ / shares shares	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Debt Instrument [Line Items]
Accrued interest		$ 37,000,000	$ 18,000,000
Interest expense		313,000,000	286,000,000	$ 302,000,000
Federal funds purchased outstanding amount		0	0
Federal funds purchased, average balance		$ 466,000,000	$ 81,000,000
Federal fund purchased Weighted average interest rate		1.65%	0.09%
Federal fund purchased, interest expenses		$ 8,000,000	$ 0	1,000,000
Junior subordinated debentures		$ 608,000,000	361,000,000
Capital security, term (in years)		10 years
Gross proceeds of BONUSES, debt		$ 9,479,000,000	2,072,000,000	6,925,000,000
Subordinated notes outstanding		432,000,000	296,000,000
Outstanding repurchase agreements			800,000,000
Interest expense on subordinated notes		19,000,000	18,000,000	18,000,000
Repurchase Agreements
Debt Instrument [Line Items]
Accrued interest			2,000,000
Interest expense		14,000,000	18,000,000	18,000,000
Short-term debt outstanding amount		0	0
Outstanding repurchase agreements		0	800,000,000
Federal Home Loan Bank Advances
Debt Instrument [Line Items]
Interest expense		251,000,000	233,000,000	246,000,000
BONUSESSM units | New York Community Capital Trust V (BONUSES Units)
Debt Instrument [Line Items]
Public offering of Bifurcated Option Note Unit Securities ("BONUSES units") | shares	5,500,000
Public offering of units, offering price per share | $ / shares	$ 50.00
Warrants and capital securities non-callable period	5 years
Gross proceeds of BONUSES, debt	$ 275,000,000
Difference between the assigned value and the stated liquidation amount of the capital securities is treated as an original issue discount	$ 92,400,000
Original issue discount amortized amount		64,000,000
BONUSESSM units | New York Community Capital Trust V (BONUSES Units) | Capital Units
Debt Instrument [Line Items]
Warrant to purchase, number of shares | Age	2.4953
Warrant to purchase, total number of shares | shares	13,700,000
Warrant to purchase, exercise price per share | $ / shares	$ 20.04
Capital security, term (in years)	49 years
Capital security, coupon or distribution rate	6.00%
Capital security, per share liquidation amount | $ / shares	$ 50.00
Gross proceeds of BONUSES	$ 182,600,000
BONUSESSM units | New York Community Capital Trust V (BONUSES Units) | Warrant
Debt Instrument [Line Items]
Gross proceeds of BONUSES	$ 92,400,000
Junior Subordinated Debt
Debt Instrument [Line Items]
Interest expense		22,000,000	18,000,000	$ 19,000,000
FHLB - NY
Debt Instrument [Line Items]
Unused line of credit		11,300,000,000	8,400,000,000
Overnight FHLB advances		2,800,000	0
Line of credit, average balance		$ 318,000,000	$ 6,000,000
Line of credit, weighted average interest rate		3.48%	0.36%