Other Short-Term Borrowings - Summary of Other Short-Term Borrowings (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Short-Term Debt [Abstract]
FHLB advances	$ 4,250	$ 4,300
Securities sold under repurchase agreements	320	388
Derivative collateral	0	124
Other borrowed money	24	26
Other short-term borrowings	$ 4,594	$ 4,838