SECURITIES (Narrative) (Details)	3 Months Ended
	Sep. 30, 2022 USD ($)	Mar. 31, 2022 USD ($) bankLocation	Dec. 31, 2021 USD ($)
Debt and Equity Securities, FV-NI [Line Items]
Accrued interest receivable	$ 28,500,000		$ 29,400,000
Securities held to maturity with unrealized losses			0
Amortized cost of FHLBs	18,600,000		22,600,000
Debt securities, held-to-maturity, sale		$ 2,200,000
Debt securities, held-to-maturity, sold | bankLocation		2
Debt securities, held-to-maturity securities, gross gain		$ 100,000
Debt securities, trading and equity securities, carrying value	6,739,802,000
Debt securities, held-to-maturity, transferred from available-for-sale, book value	934,500,000
OCI, debt securities, held-to-maturity, transferred from available-for-sale, unrealized gain (loss), after tax	186,300,000
Obligations of states and political subdivisions
Debt and Equity Securities, FV-NI [Line Items]
Held to maturity, allowance for credit losses	0		0
Municipal Bonds
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, held-to-maturity, transferred from available-for-sale, fair value	748,300,000
Asset Pledged as Collateral
Debt and Equity Securities, FV-NI [Line Items]
Debt securities, trading and equity securities, carrying value	$ 1,270,000,000		$ 1,660,000,000