Investment Securities - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Schedule of Investments [Line Items]
Amortized cost of investment securities	$ 3,000,000		$ 3,000,000
Federal home loan bank stock	1,061,000,000		1,146,000,000
Federal reserve bank stock	219,000,000		219,000,000
Gross realized gains	0	$ 0
Gross realized losses	0	0
Available-for-sale securities sold	0	$ 0
Federal Home Loan Bank of New York
Schedule of Investments [Line Items]
Federal home loan bank stock	587,000,000		598,000,000
Federal Home Loan Bank of Indianapolis
Schedule of Investments [Line Items]
Federal home loan bank stock	$ 255,000,000		$ 329,000,000