Unsecured Borrowings - Subordinated Borrowings (Detail) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Total subordinated Borrowings, par amount	$ 13,086	$ 13,405
Total subordinated Borrowings	$ 12,797	$ 16,892
Effective weighted average interest rate on subordinated borrowings, after hedging	4.49%	1.71%
Subordinated debt
Debt Instrument [Line Items]
Subordinated debt, par amount	$ 12,118	$ 12,437
Subordinated debt outstanding	$ 11,745	$ 15,571
Effective weighted average interest rate of subordinated debt after hedging	4.54%	1.74%
Junior subordinated debt
Debt Instrument [Line Items]
Subordinated debt, par amount	$ 968	$ 968
Junior subordinated debt	$ 1,052	$ 1,321
Effective weighted average interest rate of junior subordinated debt, after hedging	3.76%	1.31%