Borrowings - Amounts and Interest Rates of Short-term Borrowings (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Borrowings [Line Items]
Weighted-average interest rate	5.23%	4.24%
Repurchase agreements and short term borrowings	$ 5,316	$ 3,555
Repurchase Agreements [Member]
Schedule Of Borrowings [Line Items]
Weighted-average interest rate	3.26%	1.01%
Repurchase Agreements	$ 316	$ 355
FHLB Advances [Member]
Schedule Of Borrowings [Line Items]
Weighted-average interest rate	5.35%	4.59%
Other Short-Term Borrowings	$ 5,000	$ 3,200