Derivative Instruments - Summary of Notional Amounts of AFS's Trading Derivative Products (Detail) - AFS [Member] - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Interest Rate Swaps [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative, Notional Amount	$ 337	$ 185
Interest Rate Swaps-Pay-Fixed/Receive-Variable [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative, Notional Amount	989	1,275
US Treasury Securities
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative, Notional Amount	$ 0	$ 470