Long-Term Debt - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Secured Debt | FHLB and Federal Reserve Bank of New York Secured Borrowing Facilities
Debt Instrument [Line Items]
Current borrowing capacity	$ 24,524
Federal Home Loan Bank of New York | Long-term debt | Secured Debt
Debt Instrument [Line Items]
Amount outstanding under the loan agreement	1,000	$ 1,000
Long-term debt
Debt Instrument [Line Items]
Subordinated long-term debt, Fair Value	749	706
Long-term debt | Structured notes
Debt Instrument [Line Items]
Long-term debt, Fair value	$ 6,790	$ 7,672