Securities - Narrative (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Securities available-for-sale, allowance for credit losses	$ 0		$ 0
Securities held-to-maturity, allowance for credit losses	0		0
Securities held-to-maturity, past due	13,428,000,000		7,317,000,000
Securities held-to-maturity, nonaccrual	0		0
Equity securities without readily determinable fair values, impairment loss adjustment	4,000,000	$ 3,000,000
Past Due
Debt Securities, Available-for-sale [Line Items]
Securities held-to-maturity, past due	0		0
Other assets
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank stock	95,000,000		95,000,000
Federal Reserve Bank stock	$ 438,000,000		$ 498,000,000