LOANS, LEASES, AND ALLOWANCE FOR CREDIT LOSSES (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Financing Receivable, Allowance for Credit Losses [Line Items]
Net unamortized purchase premiums, discounts, and deferred loan fees and cost	$ 35,000,000		$ 35,000,000		$ 37,000,000
Accrued interest receivable	$ 289,000,000		$ 289,000,000		$ 299,000,000
Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Other assets		Other assets		Other assets
Total loans	$ 58,884,000,000		$ 58,884,000,000		$ 57,779,000,000
Loans held for sale	97,000,000		97,000,000		53,000,000
Principal balance of loans sold, serviced loans	582,000,000		582,000,000		431,000,000
Total income from loans sold	2,000,000	$ 8,000,000	5,000,000	$ 15,000,000
Interest income	0	0	0	0
Financing receivable, commitments threshold for evaluating collectively or individually	1,000,000		1,000,000
Real estate acquired through foreclosure	2,000,000		2,000,000		0
Mortgage loans in process of foreclosure	8,000,000		8,000,000		11,000,000
Nonaccrual
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing receivable, commitments threshold for evaluating individually	1,000,000		1,000,000
Doubtful
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	20,000,000		20,000,000		0
Payment deferral
Financing Receivable, Allowance for Credit Losses [Line Items]
Modified, still in default (prior year less than)	5,000,000	1,000,000	5,000,000	1,000,000
Principal forgiveness
Financing Receivable, Allowance for Credit Losses [Line Items]
Modified, principal forgiveness (less than)	1,000,000	$ 1,000,000	1,000,000	$ 1,000,000
Asset Pledged as Collateral without Right
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans held for sale	40,600,000,000		40,600,000,000		36,300,000,000
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	30,785,000,000		30,785,000,000		30,588,000,000
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	13,483,000,000		13,483,000,000		13,371,000,000
Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	14,616,000,000		14,616,000,000		13,820,000,000
Land Acquisition and Development | Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	233,000,000		233,000,000		219,000,000
Commercial and industrial | Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	16,757,000,000		16,757,000,000		16,684,000,000
Commercial and industrial | Commercial | Nonaccrual
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans	$ 173,000,000		$ 173,000,000		$ 82,000,000