Other Short-Term Borrowings - Summary of Other Short-Term Borrowings (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Short-Term Debt [Abstract]
FHLB advances	$ 4,700	$ 4,100
Securities sold under repurchase agreements	309	273
Derivative collateral	0	19
Other borrowed money	68	58
Total other short-term borrowings	$ 5,077	$ 4,450