Investment Securities - Investment Securities, Narrative (Details)	3 Months Ended			6 Months Ended
	Jun. 30, 2024 USD ($) security	Mar. 31, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) security	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) security
Schedule of Investments [Line Items]
Federal home loan bank stock | $	$ 1,565,000,000			$ 1,565,000,000		$ 1,392,000,000
Federal reserve bank stock | $	218,000,000			218,000,000		$ 203,000,000
Gross realized gains | $	1,000,000			1,000,000
Gross realized losses | $	$ 1,000,000			$ 1,000,000
Available-for-sale securities sold | $			$ 0		$ 0
Collateralized Debt Obligations
Schedule of Investments [Line Items]
Number of securities continuous unrealized loss position more than twelve months	237			237		84
Capital trust notes
Schedule of Investments [Line Items]
Number of securities continuous unrealized loss position more than twelve months	6			6		6
Asset-backed securities
Schedule of Investments [Line Items]
Number of securities continuous unrealized loss position more than twelve months	6			6		8
Corporate bonds
Schedule of Investments [Line Items]
Number of securities continuous unrealized loss position more than twelve months	12			12		12
Provision for credit loss | $	$ 3,000,000	$ 1,000,000
US Government Agencies Debt Securities
Schedule of Investments [Line Items]
Number of securities continuous unrealized loss position more than twelve months	36			36		37
Mortgage-Related Debt Securities:
Schedule of Investments [Line Items]
Number of securities continuous unrealized loss position more than twelve months	334			334		302
Mutual funds and common stock
Schedule of Investments [Line Items]
Number of securities continuous unrealized loss position more than twelve months						1
Municipal bonds
Schedule of Investments [Line Items]
Number of securities continuous unrealized loss position more than twelve months	1			1		1
Foreign notes
Schedule of Investments [Line Items]
Number of securities continuous unrealized loss position more than twelve months	1			1		1
Private Collateralized Mortgage Obligations
Schedule of Investments [Line Items]
Number of securities continuous unrealized loss position more than twelve months	2			2
Federal Home Loan Bank of New York
Schedule of Investments [Line Items]
Federal home loan bank stock | $	$ 1,000,000,000			$ 1,000,000,000		$ 861,000,000
Federal Home Loan Bank of Indianapolis
Schedule of Investments [Line Items]
Federal home loan bank stock | $	$ 329,000,000			$ 329,000,000		$ 329,000,000