Netting Arrangements for Certain Financial Instruments and Securities Financing Activities - Summary of Maturities by Category of Collateral Pledged for Repurchase Agreements and Securities Loaned Transactions (Detail) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	$ 1,902	$ 1,575
Securities loaned	188	169
Gross amount of recognized liabilities	2,090	1,744
Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	1,902	1,575
Securities loaned	188	169
Gross amount of recognized liabilities	2,090	1,744
U.S. Treasury and Agencies [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	321	378
U.S. Treasury and Agencies [Member] | Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	321	378
Residential Mortgage-Backed Securities [Member] | Agency [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	849	551
Residential Mortgage-Backed Securities [Member] | Overnight and Continuous [Member] | Agency [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	849	551
Corporate Debt Securities [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	732	646
Securities loaned	188	169
Corporate Debt Securities [Member] | Overnight and Continuous [Member]
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	732	646
Securities loaned	$ 188	$ 169