Investment Securities - Narrative (Details) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($) security shares	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) security shares	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Schedule of Investments [Line Items]
Debt securities, available-for-sale, accrued Interest	$ 67,000,000		$ 67,000,000		$ 33,000,000
Debt Securities, held-to-maturity, accrued interest	17,000,000		17,000,000		19,000,000
Write off of accrued interest receivable	$ 0	$ 0	$ 0	$ 0
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, number of positions | security	482		482
Debt securities, held-to-maturity, threshold period past due	30 days		30 days
Securities past due	$ 10,082,000,000		$ 10,082,000,000		10,279,000,000
Held-to-maturity securities, nonaccrual	0		0		0
Federal Home Loan Bank stock	19,000,000		19,000,000		197,000,000
Nonmarketable equity securities	95,000,000		95,000,000		58,000,000
Amortization method qualified affordable housing project investments	1,810,000,000		1,810,000,000		598,000,000
Total Past Due
Schedule of Investments [Line Items]
Securities past due	0		0		0
Asset Pledged as Collateral
Schedule of Investments [Line Items]
Investment securities, aggregate carrying value, pledged as collateral	$ 3,660,000,000		$ 3,660,000,000		$ 4,200,000,000
Visa, Inc | Class B Common Stock
Schedule of Investments [Line Items]
Investment owned (in shares) | shares	354		354
Residential Mortgage Backed Securities or Government Agency Securities
Schedule of Investments [Line Items]
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, number of positions | security	415		415
Corporate Bonds
Schedule of Investments [Line Items]
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, number of positions | security	67		67
Number of debt securities | security	1		1