Investment Securities - Narrative (Details) shares in Thousands, $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2022 USD ($) security shares	Dec. 31, 2021 USD ($)	Dec. 31, 2022 USD ($) security shares	Dec. 31, 2021 USD ($)
Schedule of Investments [Line Items]
Debt securities, available-for-sale, accrued Interest	$ 33.0	$ 22.0	$ 33.0	$ 22.0
Debt Securities, held-to-maturity, accrued interest	19.0	7.0	19.0	7.0
Write off of accrued interest receivable	$ 0.0	0.0	$ 0.0	0.0
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, number of positions | security	151		151
Debt securities, held-to-maturity, threshold period past due	30 days		30 days
Securities past due	$ 10,279.0	3,809.0	$ 10,279.0	3,809.0
Held-to-maturity securities, nonaccrual	0.0	0.0	0.0	0.0
Federal Home Loan Bank stock	197.0	40.0	197.0	40.0
Nonmarketable equity securities	58.0	1.0	58.0	1.0
Amortization method qualified affordable housing project investments	598.0	157.0	598.0	157.0
Total Past Due
Schedule of Investments [Line Items]
Securities past due	0.0	0.0	0.0	0.0
Asset Pledged as Collateral
Schedule of Investments [Line Items]
Investment securities, aggregate carrying value, pledged as collateral	$ 4,200.0	$ 5,700.0	$ 4,200.0	$ 5,700.0
Visa, Inc | Class B Common Stock
Schedule of Investments [Line Items]
Investment owned (in shares) | shares	354		354
U.S. government and government agency securities
Schedule of Investments [Line Items]
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, number of positions | security	144		144
Corporate bonds
Schedule of Investments [Line Items]
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, number of positions | security	7		7