Short-Term Borrowings - Components of Other Short-Term Borrowings (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Short-Term Debt [Abstract]
FHLB advances	$ 2,500	$ 4,300
Securities sold under repurchase agreements	330	388
Derivative collateral	3	124
Other borrowed money	28	26
Other short-term borrowings	$ 2,861	$ 4,838