Borrowed Funds - Narrative (Details) - USD ($)		12 Months Ended
	Nov. 04, 2002	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument
Interest payable		$ 51,000,000	$ 50,000,000
FHLB lock out term		5 years
FHLB interest expense		$ 1,000,000,000	564,000,000	$ 251,000,000
Offering price (in dollars per share)		$ 7.50
Warrant or right, coupon rate	6.00%
Warrant term	49 years
Noncallable term	5 years
Issuance of warrants to purchase common shares		$ 302,000,000
Settlement terms, fair value of shares amount		182,600,000
Unamortized discount		$ 63,000,000
Settlement terms, period		49 years
Outstanding principal amount		$ 212,000,000
Deferrable term		5 years
Junior subordinated debenture, interest expense		$ 49,000,000	48,000,000	$ 22,000,000
Subordinated notes		444,000,000	438,000,000
New York Community Capital Trust V (BONUSES Units)
Debt Instrument
Junior subordinated debentures		148,000,000
Unamortized discount		92,400,000
Additional Paid-in Capital
Debt Instrument
Issuance of warrants to purchase common shares		302,000,000
BONUSES Units
Debt Instrument
Offering price (in dollars per share)	$ 50.00
Warrant outstanding (in shares)	5,500,000
Warrants proceeds amount	$ 275,000,000
As Initially Reported
Debt Instrument
Junior subordinated debentures		$ 610,000,000	$ 609,000,000