Investment Securities - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, transfer to held-to-maturity	$ 1,990,000,000	$ 500,800,000
Debt securities, held-to-maturity transfer, unrealized gain	147,000,000
Debt securities, held-to-maturity transfer, unrealized loss	690,000
Available-for-sale, transfer to held-to-maturity, gain (loss)	0
Held to maturity mortgage backed securities	3,761,094,000	1,530,500,000
Available for sale mortgage backed securities	4,331,413,000	7,130,861,000
Held-to-maturity, interest receivable	20,700,000
Available-for-sale, interest receivable	16,700,000
Available-for-sale securities	3,852,854,000	7,113,545,000
Securities valued at less than historical cost, amount	$ 3,796,281,000
Securities valued at less than historical cost (as percent)	98.50%
Securities - AFS	$ 0	(312,000)	$ (61,000)
Provision for credit losses		312,000
Securities pledged as collateral	3,960,000,000	3,880,000,000
Realized gains	46,000	15,900,000	54,800,000
Realized losses	$ 324,000	$ 422,000	$ 15,000
Income tax benefit related to security gains (losses) (as percent)	26.135%	26.135%	26.135%
Commercial Mortgage Backed Securities
Debt Securities, Available-for-sale [Line Items]
Held to maturity mortgage backed securities	$ 149,200,000	$ 4,900,000
Available for sale mortgage backed securities	1,070,000,000.00	1,530,000,000
Residential Mortgage Backed Securities
Debt Securities, Available-for-sale [Line Items]
Held to maturity mortgage backed securities	1,040,000,000.00	65,500,000
Available for sale mortgage backed securities	1,470,000,000	2,920,000,000
Bonds
Debt Securities, Available-for-sale [Line Items]
Investments sold, amount	$ 0	$ 342,600,000	$ 1,700,000,000